Deer presence rather than abundance determines the population density of the sheep tick, Ixodes ricinus, in Dutch forests.

PubMed

Hofmeester, Tim R; Sprong, Hein; Jansen, Patrick A; Prins, Herbert H T; van Wieren, Sipke E

2017-09-19

Understanding which factors drive population densities of disease vectors is an important step in assessing disease risk. We tested the hypothesis that the density of ticks from the Ixodes ricinus complex, which are important vectors for tick-borne diseases, is determined by the density of deer, as adults of these ticks mainly feed on deer. We performed a cross-sectional study to investigate I. ricinus density across 20 forest plots in the Netherlands that ranged widely in deer availability to ticks, and performed a deer-exclosure experiment in four pairs of 1 ha forest plots in a separate site. Ixodes ricinus from all stages were more abundant in plots with deer (n = 17) than in plots without deer (n = 3). Where deer were present, the density of ticks did not increase with the abundance of deer. Experimental exclosure of deer reduced nymph density by 66% and adult density by 32% within a timeframe of two years. In this study, deer presence rather than abundance explained the density of I. ricinus. This is in contrast to previous studies and might be related to the relatively high host-species richness in Dutch forests. This means that reduction of the risk of acquiring a tick bite would require the complete elimination of deer in species rich forests. The fact that small exclosures (< 1 ha) substantially reduced I. ricinus densities suggests that fencing can be used to reduce tick-borne disease risk in areas with high recreational pressure.

Urban Breeding Corvids as Disseminators of Ticks and Emerging Tick-Borne Pathogens.

PubMed

Sándor, Attila D; Kalmár, Zsuzsa; Matei, Ioana; Ionică, Angela Monica; Mărcuţan, Ioan-Daniel

2017-02-01

Crows (Corvidae) are common city dwellers worldwide and are increasingly important subjects of epidemiology studies. Although their importance as hosts and transmitters of a number of zoonotic parasites and pathogens is well known, there are no studies on their importance as tick hosts. After mosquitoes, ticks are the most important vectors of zoonotic pathogens, especially for those causing emerging zoonotic diseases. Pathogenic bacteria, especially Borrelia spp., Rickettsia spp., and Anaplasma spp., vectored by ticks, are the cause for most vector-borne diseases in Europe. Here we report on ticks and tick-borne pathogens harbored by urban breeding crows. A total of 36 birds (33.33%, n = 108) hosted ticks, with 91 individual ticks belonging to 6 species (Haemaphysalis concinna, Haemaphysalis parva, Haemaphysalis punctata, Hyalomma marginatum, Ixodes arboricola, and Ixodes ricinus). Rickettsia spp. DNA was found in 6.6% of ticks and 1.9% of bird tissues, whereas Anaplasma phagocytophilum was found in 5.9% of ticks and 0.9% of birds. Two rickettsial genospecies were located, Rickettsia helvetica and Rickettsia monacensis. This is the first study to determine such a diverse tick spectrum feeding on urban corvids, while highlighting their importance as tick hosts and raising concerns about their potential risk to human health.

A Roadmap for Tick-Borne Flavivirus Research in the "Omics" Era.

PubMed

Grabowski, Jeffrey M; Hill, Catherine A

2017-01-01

Tick-borne flaviviruses (TBFs) affect human health globally. Human vaccines provide protection against some TBFs, and antivirals are available, yet TBF-specific control strategies are limited. Advances in genomics offer hope to understand the viral complement transmitted by ticks, and to develop disruptive, data-driven technologies for virus detection, treatment, and control. The genome assemblies of Ixodes scapularis , the North American tick vector of the TBF, Powassan virus, and other tick vectors, are providing insights into tick biology and pathogen transmission and serve as nucleation points for expanded genomic research. Systems biology has yielded insights to the response of tick cells to viral infection at the transcript and protein level, and new protein targets for vaccines to limit virus transmission. Reverse vaccinology approaches have moved candidate tick antigenic epitopes into vaccine development pipelines. Traditional drug and in silico screening have identified candidate antivirals, and target-based approaches have been developed to identify novel acaricides. Yet, additional genomic resources are required to expand TBF research. Priorities include genome assemblies for tick vectors, "omic" studies involving high consequence pathogens and vectors, and emphasizing viral metagenomics, tick-virus metabolomics, and structural genomics of TBF and tick proteins. Also required are resources for forward genetics, including the development of tick strains with quantifiable traits, genetic markers and linkage maps. Here we review the current state of genomic research on ticks and tick-borne viruses with an emphasis on TBFs. We outline an ambitious 10-year roadmap for research in the "omics era," and explore key milestones needed to accomplish the goal of delivering three new vaccines, antivirals and acaricides for TBF control by 2030.

A Roadmap for Tick-Borne Flavivirus Research in the “Omics” Era

PubMed Central

Grabowski, Jeffrey M.; Hill, Catherine A.

2017-01-01

Tick-borne flaviviruses (TBFs) affect human health globally. Human vaccines provide protection against some TBFs, and antivirals are available, yet TBF-specific control strategies are limited. Advances in genomics offer hope to understand the viral complement transmitted by ticks, and to develop disruptive, data-driven technologies for virus detection, treatment, and control. The genome assemblies of Ixodes scapularis, the North American tick vector of the TBF, Powassan virus, and other tick vectors, are providing insights into tick biology and pathogen transmission and serve as nucleation points for expanded genomic research. Systems biology has yielded insights to the response of tick cells to viral infection at the transcript and protein level, and new protein targets for vaccines to limit virus transmission. Reverse vaccinology approaches have moved candidate tick antigenic epitopes into vaccine development pipelines. Traditional drug and in silico screening have identified candidate antivirals, and target-based approaches have been developed to identify novel acaricides. Yet, additional genomic resources are required to expand TBF research. Priorities include genome assemblies for tick vectors, “omic” studies involving high consequence pathogens and vectors, and emphasizing viral metagenomics, tick-virus metabolomics, and structural genomics of TBF and tick proteins. Also required are resources for forward genetics, including the development of tick strains with quantifiable traits, genetic markers and linkage maps. Here we review the current state of genomic research on ticks and tick-borne viruses with an emphasis on TBFs. We outline an ambitious 10-year roadmap for research in the “omics era,” and explore key milestones needed to accomplish the goal of delivering three new vaccines, antivirals and acaricides for TBF control by 2030. PMID:29312896

Methods for control of tick vectors of Lyme Borreliosis

USGS Publications Warehouse

Jaenson, T.G.T.; Fish, D.; Ginsberg, H.S.; Gray, J.S.; Mather, T.N.; Piesman, J.

1991-01-01

During the IVth International Conference on Lyme Borreliosis in Stockholm, 1990, a workshop on control of Lyme disease vectors briefly reviewed: basic ecological principles for tick control; biocontrol of ticks; chemical control, including the use of repellents and use of permethrin-treated rodent nest material; tick control by habitat modification; and reduction of tick host availability. It was concluded that, although much research work remains, Lyme borreliosis is to a large extent a preventable infection. Avoidance of heavily tick-infested areas, personal protection using proper clothing, and prompt removal of attached ticks remain the most effective protective measures. Many other prophylactic measures are available and could be efficiently integrated into schemes to reduce the abundance of vectors. However, since the ecology of the infection varies greatly between different localities it may be necessary to apply different combinations of control methods in different endemic regions.

Tick salivary compounds: their role in modulation of host defences and pathogen transmission

PubMed Central

Kazimírová, Mária; Štibrániová, Iveta

2013-01-01

Ticks require blood meal to complete development and reproduction. Multifunctional tick salivary glands play a pivotal role in tick feeding and transmission of pathogens. Tick salivary molecules injected into the host modulate host defence responses to the benefit of the feeding ticks. To colonize tick organs, tick-borne microorganisms must overcome several barriers, i.e., tick gut membrane, tick immunity, and moulting. Tick-borne pathogens co-evolved with their vectors and hosts and developed molecular adaptations to avoid adverse effects of tick and host defences. Large gaps exist in the knowledge of survival strategies of tick-borne microorganisms and on the molecular mechanisms of tick-host-pathogen interactions. Prior to transmission to a host, the microorganisms penetrate and multiply in tick salivary glands. As soon as the tick is attached to a host, gene expression and production of salivary molecules is upregulated, primarily to facilitate feeding and avoid tick rejection by the host. Pathogens exploit tick salivary molecules for their survival and multiplication in the vector and transmission to and establishment in the hosts. Promotion of pathogen transmission by bioactive molecules in tick saliva was described as saliva-assisted transmission (SAT). SAT candidates comprise compounds with anti-haemostatic, anti-inflammatory and immunomodulatory functions, but the molecular mechanisms by which they mediate pathogen transmission are largely unknown. To date only a few tick salivary molecules associated with specific pathogen transmission have been identified and their functions partially elucidated. Advanced molecular techniques are applied in studying tick-host-pathogen interactions and provide information on expression of vector and pathogen genes during pathogen acquisition, establishment and transmission. Understanding the molecular events on the tick-host-pathogen interface may lead to development of new strategies to control tick-borne diseases. PMID:23971008

Vectors as Epidemiological Sentinels: Patterns of Within-Tick Borrelia burgdorferi Diversity

PubMed Central

Walter, Katharine S.; Carpi, Giovanna; Evans, Benjamin R.; Caccone, Adalgisa; Diuk-Wasser, Maria A.

2016-01-01

Hosts including humans, other vertebrates, and arthropods, are frequently infected with heterogeneous populations of pathogens. Within-host pathogen diversity has major implications for human health, epidemiology, and pathogen evolution. However, pathogen diversity within-hosts is difficult to characterize and little is known about the levels and sources of within-host diversity maintained in natural populations of disease vectors. Here, we examine genomic variation of the Lyme disease bacteria, Borrelia burgdorferi (Bb), in 98 individual field-collected tick vectors as a model for study of within-host processes. Deep population sequencing reveals extensive and previously undocumented levels of Bb variation: the majority (~70%) of ticks harbor mixed strain infections, which we define as levels Bb diversity pre-existing in a diverse inoculum. Within-tick diversity is thus a sample of the variation present within vertebrate hosts. Within individual ticks, we detect signatures of positive selection. Genes most commonly under positive selection across ticks include those involved in dissemination in vertebrate hosts and evasion of the vertebrate immune complement. By focusing on tick-borne Bb, we show that vectors can serve as epidemiological and evolutionary sentinels: within-vector pathogen diversity can be a useful and unbiased way to survey circulating pathogen diversity and identify evolutionary processes occurring in natural transmission cycles. PMID:27414806

Visualization of Microbiota in Tick Guts by Whole-mount In Situ Hybridization.

PubMed

Moss, Caitlin E; Robson, Andrew; Fikrig, Erol; Narasimhan, Sukanya

2018-06-01

Infectious diseases transmitted by arthropod vectors continue to pose a significant threat to human health worldwide. The pathogens causing these diseases, do not exist in isolation when they colonize the vector; rather, they likely engage in interactions with resident microorganisms in the gut lumen. The vector microbiota has been demonstrated to play an important role in pathogen transmission for several vector-borne diseases. Whether resident bacteria in the gut of the Ixodes scapularis tick, the vector of several human pathogens including Borrelia burgdorferi, influence tick transmission of pathogens is not determined. We require methods for characterizing the composition of the bacteria associated with the tick gut to facilitate a better understanding of potential interspecies interactions in the tick gut. Using whole-mount in situ hybridization to visualize RNA transcripts associated with particular bacterial species allows for the collection of qualitative data regarding the abundance and distribution of the microbiota in intact tissue. This technique can be used to examine changes in the gut microbiota milieu over the course of tick feeding and can also be applied to analyze expression of tick genes. Staining of whole tick guts yield information about the gross spatial distribution of target RNA in the tissue without the need for three-dimensional reconstruction and is less affected by environmental contamination, which often confounds the sequencing-based methods frequently used to study complex microbial communities. Overall, this technique is a valuable tool that can be used to better understand vector-pathogen-microbiota interactions and their role in disease transmission.

Comparison of the lifetime host-to-tick transmission between two strains of the Lyme disease pathogen Borrelia afzelii.

PubMed

Jacquet, Maxime; Margos, Gabriele; Fingerle, Volker; Voordouw, Maarten J

2016-12-16

Transmission from the vertebrate host to the arthropod vector is a critical step in the life-cycle of any vector-borne pathogen. How the probability of host-to-vector transmission changes over the duration of the infection is an important predictor of pathogen fitness. The Lyme disease pathogen Borrelia afzelii is transmitted by Ixodes ricinus ticks and establishes a chronic infection inside rodent reservoir hosts. The present study compares the temporal pattern of host-to-tick transmission between two strains of B. afzelii. Laboratory mice were experimentally infected via tick bite with one of two strains of B. afzelii: A3 and A10. Mice were repeatedly infested with pathogen-free larval Ixodes ricinus ticks over a period of 4 months. Engorged larval ticks moulted into nymphal ticks that were tested for infection with B. afzelii using qPCR. The proportion of infected nymphs was used to characterize the pattern of host-to-tick transmission over time. Both strains of B. afzelii followed a similar pattern of host-to-tick transmission. Transmission decreased from the acute to the chronic phase of the infection by 16.1 and 29.3% for strains A3 and A10, respectively. Comparison between strains found no evidence of a trade-off in transmission between the acute and chronic phase of infection. Strain A10 had higher lifetime fitness and established a consistently higher spirochete load in nymphal ticks than strain A3. Quantifying the relationship between host-to-vector transmission and the age of infection in the host is critical for estimating the lifetime fitness of vector-borne pathogens.

Cotransmission of Divergent Relapsing Fever Spirochetes by Artificially Infected Ornithodoros hermsi▿†

PubMed Central

Policastro, Paul F.; Raffel, Sandra J.; Schwan, Tom G.

2011-01-01

The soft tick Ornithodoros hermsi, which ranges in specific arboreal zones of western North America, acts as a vector for the relapsing fever spirochete Borrelia hermsii. Two genomic groups (genomic group I [GGI] and GGII) of B. hermsii are differentiated by multilocus sequence typing yet are codistributed in much of the vector's range. To test whether the tick vector can be infected via immersion, noninfected, colony-derived O. hermsi larvae were exposed to reduced-humidity conditions before immersion in culture suspensions of several GGI and GGII isolates. We tested for spirochetes in ticks by immunofluorescence microscopy and in mouse blood by quantitative PCR of the vtp locus to differentiate spirochete genotypes. The immersed larval ticks were capable of spirochete transmission to mice at the first nymphal feeding. Tick infection with mixed cultures of isolates DAH (vtp-6) (GGI) and MTW-2 (vtp-5) (GGII) resulted in ticks that caused spirochetemias in mice consisting of MTW-2 or both DAH and MTW-2. These findings show that this soft tick species can acquire B. hermsii by immersion in spirochete suspensions, that GGI and GGII isolates can coinfect the tick vector by this method, and that these spirochetes can be cotransmitted to a rodent host. PMID:21965393

Spatial disaggregation of tick occurrence and ecology at a local scale as a preliminary step for spatial surveillance of tick-borne diseases: general framework and health implications in Belgium.

PubMed

Obsomer, Valerie; Wirtgen, Marc; Linden, Annick; Claerebout, Edwin; Heyman, Paul; Heylen, Dieter; Madder, Maxime; Maris, Jo; Lebrun, Maude; Tack, Wesley; Lempereur, Laetitia; Hance, Thierry; Van Impe, Georges

2013-06-22

The incidence of tick-borne diseases is increasing in Europe. Sub national information on tick distribution, ecology and vector status is often lacking. However, precise location of infection risk can lead to better targeted prevention measures, surveillance and control. In this context, the current paper compiled geolocated tick occurrences in Belgium, a country where tick-borne disease has received little attention, in order to highlight the potential value of spatial approaches and draw some recommendations for future research priorities. Mapping of 89,289 ticks over 654 sites revealed that ticks such as Ixodes ricinus and Ixodes hexagonus are largely present while Dermacentor reticulatus has a patchy distribution. Suspected hot spots of tick diversity might favor pathogen exchanges and suspected hot spots of I. ricinus abundance might increase human-vector contact locally. This underlines the necessity to map pathogens and ticks in detail. While I. ricinus is the main vector, I. hexagonus is a vector and reservoir of Borrelia burgdorferi s.l., which is active the whole year and is also found in urban settings. This and other nidiculous species bite humans less frequently, but seem to harbour pathogens. Their role in maintaining a pathogenic cycle within the wildlife merits investigation as they might facilitate transmission to humans if co-occurring with I. ricinus. Many micro-organisms are found abroad in tick species present in Belgium. Most have not been recorded locally but have not been searched for. Some are transmitted directly at the time of the bite, suggesting promotion of tick avoidance additionally to tick removal. This countrywide approach to tick-borne diseases has helped delineate recommendations for future research priorities necessary to design public health policies aimed at spatially integrating the major components of the ecological cycle of tick-borne diseases. A systematic survey of tick species and associated pathogens is called for in Europe, as well as better characterisation of species interaction in the ecology of tick-borne diseases, those being all tick species, pathogens, hosts and other species which might play a role in tick-borne diseases complex ecosystems.

Vector biodiversity did not associate with tick-borne pathogen prevalence in small mammal communities in northern and central California.

PubMed

Foley, Janet; Piovia-Scott, Jonah

2014-04-01

Vector and host abundance affect infection transmission rates, prevalence, and persistence in communities. Biological diversity in hosts and vectors may provide "rescue" hosts which buffer against pathogen extinction and "dilution" hosts which reduce the force of infection in communities. Anaplasma phagocytophilum is a tick-transmitted zoonotic pathogen that circulates in small mammal and tick communities characterized by varying levels of biological diversity. We examined the prevalence of A. phagocytophilum in Ixodes spp. ticks in 11 communities in northern and central California. A total of 1020 ticks of 8 species was evaluated. Five percent of ticks (5 species) were PCR-positive, with the highest prevalence (6-7%) in I. pacificus and I. ochotonae. In most species, adults had a higher prevalence than nymphs or larvae. PCR prevalence varied between 0% and 40% across sites; the infection probability in ticks increased with infestation load and prevalence in small mammals, but not tick species richness, diversity, evenness, or small mammal species richness. No particular tick species was likely to "rescue" infection in the community; rather the risk of A. phagocytophilum infection is related to exposure to particular tick species and life stages, and overall tick abundance. Copyright © 2014 Elsevier GmbH. All rights reserved.

Cross-reactive acquired immunity influences transmission success of the Lyme disease pathogen, Borrelia afzelii.

PubMed

Jacquet, Maxime; Durand, Jonas; Rais, Olivier; Voordouw, Maarten J

2015-12-01

Cross-reactive acquired immunity in the vertebrate host induces indirect competition between strains of a given pathogen species and is critical for understanding the ecology of mixed infections. In vector-borne diseases, cross-reactive antibodies can reduce pathogen transmission at the vector-to-host and the host-to-vector lifecycle transition. The highly polymorphic, immunodominant, outer surface protein C (OspC) of the tick-borne spirochete bacterium Borrelia afzelii induces a strong antibody response in the vertebrate host. To test how cross-immunity in the vertebrate host influences tick-to-host and host-to-tick transmission, mice were immunized with one of two strain-specific recombinant OspC proteins (A3, A10), challenged via tick bite with one of the two B. afzelii ospC strains (A3, A10), and infested with xenodiagnostic ticks. Immunization with a given rOspC antigen protected mice against homologous strains carrying the same major ospC group allele but provided little or no cross-protection against heterologous strains carrying a different major ospC group allele. There were cross-immunity effects on the tick spirochete load but not on the probability of host-to-tick transmission. The spirochete load in ticks that had fed on mice with cross-immune experience was reduced by a factor of two compared to ticks that had fed on naive control mice. In addition, strain-specific differences in mouse spirochete load, host-to-tick transmission, tick spirochete load, and the OspC-specific IgG response revealed the mechanisms that determine variation in transmission success between strains of B. afzelii. This study shows that cross-immunity in infected vertebrate hosts can reduce pathogen load in the arthropod vector with potential consequences for vector-to-host pathogen transmission. Copyright © 2015 Elsevier B.V. All rights reserved.

Tissue Distribution of the Ehrlichia muris-Like Agent in a Tick Vector

PubMed Central

Lynn, Geoffrey E.; Oliver, Jonathan D.; Nelson, Curtis M.; Felsheim, Roderick F.; Kurtti, Timothy J.; Munderloh, Ulrike G.

2015-01-01

Human pathogens transmitted by ticks undergo complex life cycles alternating between the arthropod vector and a mammalian host. While the latter has been investigated to a greater extent, examination of the biological interactions between microbes and the ticks that carry them presents an equally important opportunity for disruption of the disease cycle. In this study, we used in situ hybridization to demonstrate infection by the Ehrlichia muris-like organism, a newly recognized human pathogen, of Ixodes scapularis ticks, a primary vector for several important human disease agents. This allowed us to assess whole sectioned ticks for the patterns of tissue invasion, and demonstrate generalized dissemination of ehrlichiae in a variety of cell types and organs within ticks infected naturally via blood feeding. Electron microscopy was used to confirm these results. Here we describe a strong ehrlichial affinity for epithelial cells, neuronal cells of the synganglion, salivary glands, and male accessory glands. PMID:25781930

Vector prevalence and detection of Crimean-Congo haemorrhagic fever virus in Golestan Province, Iran.

PubMed

Sedaghat, Mohammad Mehdi; Sarani, Moslem; Chinikar, Sadegh; Telmadarraiy, Zakiye; Moghaddam, Abdolreza Salahi; Azam, Kamal; Nowotny, Norbert; Fooks, Anthony R; Shahhosseini, Nariman

2017-01-01

Crimean-Congo haemorrhagic fever virus (CCHFV) causes severe disease with fatality rate of 30%. The virus is transmitted to humans through the bite of an infected tick, direct contact with the products of infected livestock as well as nosocomially. The disease occurs sporadically throughout many of African, Asian and European countries. Different species of ticks serve either as vector or reservoir for CCHFV. This study was aimed to determine the prevalence of CCHFV in hard ticks (Ixodidae) in the Golestan Province of Iran. A molecular survey was conducted on hard ticks (Ixodidae) isolated from six counties in Golestan Province, north of Iran during 2014-15. The ticks were identified using morphological characteristics and presence of CCHFV RNA was detected using RT-PCR. Data revealed the presence of CCHFV in 5.3% of the ticks selected for screening. The infected ticks belonged to Hyalomma dromedarii, Hy. anatolicum, Hy. marginatum and Rhipicephalus sanguineus species. The study demonstrated that Hyalomma ticks are the main vectors of CCHFV in Golestan Province. Thus, preventive strategies such as using acaricides and repellents in order to avoid contact with Hyalomma ticks are proposed.

Acquisition and transmission of Theileria parva by vector tick, Rhipicephalus appendiculatus.

PubMed

Konnai, Satoru; Imamura, Saiki; Nakajima, Chie; Witola, William Harold; Yamada, Shinji; Simuunza, Martin; Nambota, Andrew; Yasuda, Jun; Ohashi, Kazuhiko; Onuma, Misao

2006-08-01

In order to investigate the transmission dynamics of Theileria parva (T. parva) by the brown ear tick, Rhipicephalus appendiculatus (R. appendiculatus), under experimental conditions, detection of T. parva in ticks and cattle was performed by a quantitative real-time PCR assay. A calf inoculated with a T. parva mixture became PCR-positive for T. parva infection on day 8 post-inoculation, and subsequently, nymphal ticks were introduced and maintained to feed on the infected calf for 6 days. Engorged nymphs were collected daily and allowed to molt into adults, and overall, 70.8% (121/171) of the adult ticks acquired the T. parva infection. Furthermore, the T. parva infection rate in ticks under field conditions was monitored by real-time PCR in R. appendiculatus ticks collected from a traditionally managed pastoral land of Zambia, on which Sanga breed cattle are traditionally reared and the area has endemic East Coast fever (ECF). A total of 70 cattle were randomly selected in the same area and 67 (95.7%) were found to be serologically positive for R. appendiculatus tick antigen (RIM36). Twenty-nine (43.3%) of the 67 serologically positive cattle were real-time PCR-positive for T. parva, although no piroplasms could be detected in the blood smears. Unexpectedly, out of 614 R. appendiculatus nymphal and adult ticks collected by flagging vegetation, 4.1% were positive for T. parva DNA. However, since the rate of transmission of T. parva from infected cattle to ticks and vice versa and the serological evidence of exposure to R. appendiculatus ticks in naturally exposed cattle were relatively high, it would be wise in such a case to consider vector control as well as vaccination against ECF as control measures.

Establishment of a novel tick-Babesia experimental infection model.

PubMed

Maeda, Hiroki; Hatta, Takeshi; Alim, M Abdul; Tsubokawa, Daigo; Mikami, Fusako; Matsubayashi, Makoto; Miyoshi, Takeharu; Umemiya-Shirafuji, Rika; Kawazu, Shin-Ichiro; Igarashi, Ikuo; Mochizuki, Masami; Tsuji, Naotoshi; Tanaka, Tetsuya

2016-11-14

Ticks are potent vectors of many deadly human and animal pathogens. Tick-borne babesiosis is a well-recognized malaria-like disease that occurs worldwide and recently has attracted increased attention as an emerging zoonosis. Although the proliferation of Babesia organisms is essential in the vectors, their detailed lifecycle with time information for migration in ticks remains unknown. A novel study model for the elucidation of the migration speed of Babesia parasites in their vector tick, Haemaphysalis longicornis, has been developed using an artificial feeding system with quantitative PCR method. The detectable DNA of Babesia parasites gradually disappeared in the tick midgut at 1 day post engorgement (DPE), and in contrary increased in other organs. The results indicated that the Babesia parasite passed the H. longicornis midgut within 24 hours post engorgement, migrated to the hemolymph, and then proliferated in the organs except the midgut. This time point may be an important curfew for Babesia parasites to migrate in the tick lumen. We also visualized the Babesia parasites in the experimentally infected ticks and in their eggs using IFAT for detecting their cytoskeletal structure, which suggested the successful tick infection and transovarial transmission of the parasite. This model will shed light on the further understanding of tick-Babesia interactions.

Establishment of a novel tick-Babesia experimental infection model

PubMed Central

Maeda, Hiroki; Hatta, Takeshi; Alim, M Abdul; Tsubokawa, Daigo; Mikami, Fusako; Matsubayashi, Makoto; Miyoshi, Takeharu; Umemiya-Shirafuji, Rika; Kawazu, Shin-ichiro; Igarashi, Ikuo; Mochizuki, Masami; Tsuji, Naotoshi; Tanaka, Tetsuya

2016-01-01

Ticks are potent vectors of many deadly human and animal pathogens. Tick-borne babesiosis is a well-recognized malaria-like disease that occurs worldwide and recently has attracted increased attention as an emerging zoonosis. Although the proliferation of Babesia organisms is essential in the vectors, their detailed lifecycle with time information for migration in ticks remains unknown. A novel study model for the elucidation of the migration speed of Babesia parasites in their vector tick, Haemaphysalis longicornis, has been developed using an artificial feeding system with quantitative PCR method. The detectable DNA of Babesia parasites gradually disappeared in the tick midgut at 1 day post engorgement (DPE), and in contrary increased in other organs. The results indicated that the Babesia parasite passed the H. longicornis midgut within 24 hours post engorgement, migrated to the hemolymph, and then proliferated in the organs except the midgut. This time point may be an important curfew for Babesia parasites to migrate in the tick lumen. We also visualized the Babesia parasites in the experimentally infected ticks and in their eggs using IFAT for detecting their cytoskeletal structure, which suggested the successful tick infection and transovarial transmission of the parasite. This model will shed light on the further understanding of tick-Babesia interactions. PMID:27841321

Changes in Black-legged Tick Population in New England with Future Climate Change

NASA Astrophysics Data System (ADS)

Krishnan, S.; Huber, M.

2015-12-01

Lyme disease is one of the most frequently reported vector-borne diseases in the United States. In the Northeastern United States, vector transmission is maintained in a horizontal transmission cycle between the vector, the black-legged ticks, and the vertebrate reservoir hosts, which include white-tailed deer, rodents and other medium to large sized mammals. Predicting how vector populations change with future climate change is critical to understanding disease spread in the future, and for developing suitable regional adaptation strategies. For the United States, these predictions have mostly been made using regressions based on field and lab studies, or using spatial suitability studies. However, the relation between tick populations at various life-cycle stages and climate variables are complex, necessitating a mechanistic approach. In this study, we present a framework for driving a mechanistic tick population model with high-resolution regional climate modeling projections. The goal is to estimate changes in black-legged tick populations in New England for the 21st century. The tick population model used is based on the mechanistic approach of Ogden et al., (2005) developed for Canada. Dynamically downscaled climate projections at a 3-kms resolution using the Weather and Research Forecasting Model (WRF) are used to drive the tick population model.

Transmission of tick-borne pathogens between co-feeding ticks: Milan Labuda's enduring paradigm.

PubMed

Randolph, Sarah E

2011-12-01

During the 1990s, Milan Labuda's experimental results established a new paradigm for the study of tick-borne viruses that has since been strengthened by its demonstrated effectiveness in explaining the epidemiology of tick-borne encephalitis (TBE). This brief review summarizes the essential features of the transmission of tick-borne pathogens such as TBE virus. Leukocytes migrate between tick feeding sites, bearing infective virions and providing a transport route for the virus between co-feeding ticks independent of a systemic viraemia. Such tick-borne pathogens are thus transmitted from tick to tick via vertebrates; the ticks are the reservoirs as well as the vectors, while the vertebrate is the transient bridge. The aim is to bring the related but non-synonymous terms (co-feeding and non-systemic) to the attention of workers who use simple PCR screening to identify additional vertebrate reservoir hosts of vector-borne pathogens that are not in fact maintained in nature through systemic transmission. Copyright © 2011 Elsevier GmbH. All rights reserved.

Spatial disaggregation of tick occurrence and ecology at a local scale as a preliminary step for spatial surveillance of tick-borne diseases: general framework and health implications in Belgium

PubMed Central

2013-01-01

Background The incidence of tick-borne diseases is increasing in Europe. Sub national information on tick distribution, ecology and vector status is often lacking. However, precise location of infection risk can lead to better targeted prevention measures, surveillance and control. Methods In this context, the current paper compiled geolocated tick occurrences in Belgium, a country where tick-borne disease has received little attention, in order to highlight the potential value of spatial approaches and draw some recommendations for future research priorities. Results Mapping of 89,289 ticks over 654 sites revealed that ticks such as Ixodes ricinus and Ixodes hexagonus are largely present while Dermacentor reticulatus has a patchy distribution. Suspected hot spots of tick diversity might favor pathogen exchanges and suspected hot spots of I. ricinus abundance might increase human-vector contact locally. This underlines the necessity to map pathogens and ticks in detail. While I. ricinus is the main vector, I. hexagonus is a vector and reservoir of Borrelia burgdorferi s.l., which is active the whole year and is also found in urban settings. This and other nidiculous species bite humans less frequently, but seem to harbour pathogens. Their role in maintaining a pathogenic cycle within the wildlife merits investigation as they might facilitate transmission to humans if co-occurring with I. ricinus. Many micro-organisms are found abroad in tick species present in Belgium. Most have not been recorded locally but have not been searched for. Some are transmitted directly at the time of the bite, suggesting promotion of tick avoidance additionally to tick removal. Conclusion This countrywide approach to tick-borne diseases has helped delineate recommendations for future research priorities necessary to design public health policies aimed at spatially integrating the major components of the ecological cycle of tick-borne diseases. A systematic survey of tick species and associated pathogens is called for in Europe, as well as better characterisation of species interaction in the ecology of tick-borne diseases, those being all tick species, pathogens, hosts and other species which might play a role in tick-borne diseases complex ecosystems. PMID:23800283

Correlation between Tick Density and Pathogen Endemicity, New Hampshire

PubMed Central

Walk, Seth T.; Xu, Guang; Stull, Jason W.

2009-01-01

To assess the endemicity of tick-borne pathogens in New Hampshire, we surveyed adult tick vectors. Pathogens were more prevalent in areas of high tick density, suggesting a correlation between tick establishment and pathogen endemicity. Infection rates in ticks correlated with disease frequency in humans. PMID:19331738

Avoiding Ticks

MedlinePlus

... ticks that bite humans How ticks spread disease Diseases transmitted by ticks Trends in tickborne diseases Tickborne diseases ... Emerging and Zoonotic Infectious Diseases (NCEZID) Division of Vector-Borne Diseases (DVBD) Email Recommend Tweet YouTube Instagram Listen Watch ...

Images in Health Surveillance: Tickborne Disease Vectors and Lyme Disease Clinical Diagnosis

DTIC Science & Technology

2012-05-01

Powassan virus encephalitis, babesiosis, and Colorado tick fever. Tick bites are also a mode of transmission for tularemia and Q fever. 15. SUBJECT...anaplasmosis, Powassan virus encephalitis, babesiosis, and Colorado tick fever. Tick bites are also a mode of trans- mission for tularemia and Q...east- ern and central U.S. and in limited areas on the Pacifi c Coast (Figure 5).4 It is the major vector of RMSF and can also trans- mit tularemia

A virulent babesia bovis strain failed to infect white-tailed deer (Odocoileus virginianus)

USDA-ARS?s Scientific Manuscript database

Wildlife are an important component in the vector-host-pathogen triangle of livestock diseases, as they maintain biological vectors that transmit pathogens and can serve as reservoirs for such infectious pathogens. Babesia bovis is a tick-borne pathogen, vectored by cattle fever ticks, Rhipicephalus...

The Epidemiology and Geographic Distribution of Relapsing Fever Borreliosis in West and North Africa, with a Review of the Ornithodoros erraticus Complex (Acari: Ixodida)

PubMed Central

Trape, Jean-François; Diatta, Georges; Arnathau, Céline; Bitam, Idir; Sarih, M’hammed; Belghyti, Driss; Bouattour, Ali; Elguero, Eric; Vial, Laurence; Mané, Youssouph; Baldé, Cellou; Pugnolle, Franck; Chauvancy, Gilles; Mahé, Gil; Granjon, Laurent; Duplantier, Jean-Marc

2013-01-01

Background Relapsing fever is the most frequent bacterial disease in Africa. Four main vector / pathogen complexes are classically recognized, with the louse Pediculus humanus acting as vector for B. recurrentis and the soft ticks Ornithodoros sonrai, O. erraticus and O. moubata acting as vectors for Borrelia crocidurae, B. hispanica and B. duttonii, respectively. Our aim was to investigate the epidemiology of the disease in West, North and Central Africa. Methods And Findings From 2002 to 2012, we conducted field surveys in 17 African countries and in Spain. We investigated the occurrence of Ornithodoros ticks in rodent burrows in 282 study sites. We collected 1,629 small mammals that may act as reservoir for Borrelia infections. Using molecular methods we studied genetic diversity among Ornithodoros ticks and Borrelia infections in ticks and small mammals. Of 9,870 burrows investigated, 1,196 (12.1%) were inhabited by Ornithodoros ticks. In West Africa, the southern and eastern limits of the vectors and Borrelia infections in ticks and small mammals were 13°N and 01°E, respectively. Molecular studies revealed the occurrence of nine different Ornithodoros species, including five species new for science, with six of them harboring Borrelia infections. Only B. crocidurae was found in West Africa and three Borrelia species were identified in North Africa: B. crocidurae, B. hispanica, and B. merionesi. Conclusions Borrelia Spirochetes responsible for relapsing fever in humans are highly prevalent both in Ornithodoros ticks and small mammals in North and West Africa but Ornithodoros ticks seem absent south of 13°N and small mammals are not infected in these regions. The number of Ornithodoros species acting as vector of relapsing fever is much higher than previously known. PMID:24223812

Vectors of Crimean Congo Hemorrhagic Fever Virus in Iran

PubMed Central

Telmadarraiy, Zakkyeh; Chinikar, Sadegh; Vatandoost, Hassan; Faghihi, Faezeh; Hosseini-Chegeni, Asadollah

2015-01-01

Background: Ticks are important vectors and reservoirs of Crimean Congo Hemorrhagic Fever (CCHF) virus. Human beings may be infected whenever the normal life cycle of the infected ticks on non-human vertebrate hosts is interrupted by the undesirable presence of humans in the cycle. A total of 26 species of Argasid and Ixodid ticks have been recorded in Iran; including nine Hyalomma, two Rhipicephalus, two Dermacentor, five Haemaphysalis, two Boophilus, one Ixodes and two Argas as well as three Ornithodoros species as blood sucking ectoparasites of livestock and poultries. The present paper reviews tick vectors of CCHF virus in Iran, focusing on the role of ticks in different provinces of Iran using reverse transcription polymerase chain reaction (RT-PCR) assay. Methods: During ten years study, 1054 tick specimens; including two species of Argasidae and 17 species of Ixodidae were examined for their infection to CCHF virus genome. The output of all studies as well as related publications were discussed in the current paper. Results: The results show that Rhipicephalus sanguineus, Hyalomma marginatum, H. anatolicum, H. asiaticum and H. dromedarii were known as the most frequent species which were positive for CCHF virus. Conclusion: The status of ticks which were positive for CCHF virus revealed that unlike the most common idea that Hyalomma species are the most important vectors of CCHF virus, other ticks including Rhipicephalus, Haemaphysalis and Dermacentor can be reservoir of this virus; thus, considering geographical distribution, type of host and environmental conditions, different tick control measurements should be carried out in areas with high incidence of CCHF disease. PMID:26623426

Bacterial and protozoal pathogens found in ticks collected from humans in Corum province of Turkey

PubMed Central

Karasartova, Djursun; Gureser, Ayse Semra; Gokce, Tuncay; Celebi, Bekir; Yapar, Derya; Keskin, Adem; Celik, Selim; Ece, Yasemin; Erenler, Ali Kemal; Usluca, Selma; Mumcuoglu, Kosta Y.

2018-01-01

Background Tick-borne diseases are increasing all over the word, including Turkey. The aim of this study was to determine the bacterial and protozoan vector-borne pathogens in ticks infesting humans in the Corum province of Turkey. Methodology/Principal findings From March to November 2014 a total of 322 ticks were collected from patients who attended the local hospitals with tick bites. Ticks were screened by real time-PCR and PCR, and obtained amplicons were sequenced. The dedected tick was belonging to the genus Hyalomma, Haemaphysalis, Rhipicephalus, Dermacentor and Ixodes. A total of 17 microorganism species were identified in ticks. The most prevalent Rickettsia spp. were: R. aeschlimannii (19.5%), R. slovaca (4.5%), R. raoultii (2.2%), R. hoogstraalii (1.9%), R. sibirica subsp. mongolitimonae (1.2%), R. monacensis (0.31%), and Rickettsia spp. (1.2%). In addition, the following pathogens were identified: Borrelia afzelii (0.31%), Anaplasma spp. (0.31%), Ehrlichia spp. (0.93%), Babesia microti (0.93%), Babesia ovis (0.31%), Babesia occultans (3.4%), Theileria spp. (1.6%), Hepatozoon felis (0.31%), Hepatozoon canis (0.31%), and Hemolivia mauritanica (2.1%). All samples were negative for Francisella tularensis, Coxiella burnetii, Bartonella spp., Toxoplasma gondii and Leishmania spp. Conclusions/Significance Ticks in Corum carry a large variety of human and zoonotic pathogens that were detected not only in known vectors, but showed a wider vector diversity. There is an increase in the prevalence of ticks infected with the spotted fever group and lymphangitis-associated rickettsiosis, while Ehrlichia spp. and Anaplasma spp. were reported for the first time from this region. B. microti was detected for the first time in Hyalomma marginatum infesting humans. The detection of B. occultans, B. ovis, Hepatozoon spp., Theileria spp. and Hemolivia mauritanica indicate the importance of these ticks as vectors of pathogens of veterinary importance, therefore patients with a tick infestation should be followed for a variety of pathogens with medical importance. PMID:29649265

Bacterial and protozoal pathogens found in ticks collected from humans in Corum province of Turkey.

PubMed

Karasartova, Djursun; Gureser, Ayse Semra; Gokce, Tuncay; Celebi, Bekir; Yapar, Derya; Keskin, Adem; Celik, Selim; Ece, Yasemin; Erenler, Ali Kemal; Usluca, Selma; Mumcuoglu, Kosta Y; Taylan-Ozkan, Aysegul

2018-04-01

Tick-borne diseases are increasing all over the word, including Turkey. The aim of this study was to determine the bacterial and protozoan vector-borne pathogens in ticks infesting humans in the Corum province of Turkey. From March to November 2014 a total of 322 ticks were collected from patients who attended the local hospitals with tick bites. Ticks were screened by real time-PCR and PCR, and obtained amplicons were sequenced. The dedected tick was belonging to the genus Hyalomma, Haemaphysalis, Rhipicephalus, Dermacentor and Ixodes. A total of 17 microorganism species were identified in ticks. The most prevalent Rickettsia spp. were: R. aeschlimannii (19.5%), R. slovaca (4.5%), R. raoultii (2.2%), R. hoogstraalii (1.9%), R. sibirica subsp. mongolitimonae (1.2%), R. monacensis (0.31%), and Rickettsia spp. (1.2%). In addition, the following pathogens were identified: Borrelia afzelii (0.31%), Anaplasma spp. (0.31%), Ehrlichia spp. (0.93%), Babesia microti (0.93%), Babesia ovis (0.31%), Babesia occultans (3.4%), Theileria spp. (1.6%), Hepatozoon felis (0.31%), Hepatozoon canis (0.31%), and Hemolivia mauritanica (2.1%). All samples were negative for Francisella tularensis, Coxiella burnetii, Bartonella spp., Toxoplasma gondii and Leishmania spp. Ticks in Corum carry a large variety of human and zoonotic pathogens that were detected not only in known vectors, but showed a wider vector diversity. There is an increase in the prevalence of ticks infected with the spotted fever group and lymphangitis-associated rickettsiosis, while Ehrlichia spp. and Anaplasma spp. were reported for the first time from this region. B. microti was detected for the first time in Hyalomma marginatum infesting humans. The detection of B. occultans, B. ovis, Hepatozoon spp., Theileria spp. and Hemolivia mauritanica indicate the importance of these ticks as vectors of pathogens of veterinary importance, therefore patients with a tick infestation should be followed for a variety of pathogens with medical importance.

Emerging arthropod-borne diseases of companion animals in Europe.

PubMed

Beugnet, Frederic; Marié, Jean-Lou

2009-08-26

Vector-borne diseases are caused by parasites, bacteria or viruses transmitted by the bite of hematophagous arthropods (mainly ticks and mosquitoes). The past few years have seen the emergence of new diseases, or re-emergence of existing ones, usually with changes in their epidemiology (i.e. geographical distribution, prevalence, and pathogenicity). The frequency of some vector-borne diseases of pets is increasing in Europe, i.e. canine babesiosis, granulocytic anaplasmosis, canine monocytic ehrlichiosis, thrombocytic anaplasmosis, and leishmaniosis. Except for the last, these diseases are transmitted by ticks. Both the distribution and abundance of the three main tick species, Rhipicephalus sanguineus, Dermacentor reticulatus and Ixodes ricinus are changing. The conditions for such changes involve primarily human factors, such as travel with pets, changes in human habitats, social and leisure activities, but climate changes also have a direct impact on arthropod vectors (abundance, geographical distribution, and vectorial capacity). Besides the most known diseases, attention should be kept on tick-borne encephalitis, which seems to be increasing in western Europe, as well as flea-borne diseases like the flea-transmitted rickettsiosis. Here, after consideration of the main reasons for changes in tick vector ecology, an overview of each "emerging" vector-borne diseases of pets is presented.

Review of methods to prevent and reduce the risk of Lyme disease.

PubMed

Lindsay, L R; Ogden, N H; Schofield, S W

2015-06-04

Cases of Lyme disease and areas with self-sustaining populations of vector ticks are increasing in Canada. This trend is expected to continue. Preventing Lyme disease will therefore become relevant to an increasing number of Canadians. To summarize methods for reducing the risk of tick bites and preventing transmission once a tick is feeding. A literature search was conducted to identify methods to reduce the risk of tick bites and the abundance of vector ticks, as well as the risk of becoming infected with the Lyme disease pathogen, Borrelia burgdorferi (BB), if bitten by a vector tick. Current approaches to reducing the risk of tick bites or preventing infection with BB once bitten are largely reliant on the individual. They include use of topical repellents, use of protective clothing, avoidance of risk areas and removing ticks soon (ideally within a day) after they attach. These methods are efficacious, but constrained by user adherence. Other approaches such as landscape modification or the use of acaricides to control ticks, have shown promise in other countries, but have not been widely adopted in Canada. Lyme disease will continue to present a threat in Canada. In additional to the existing interventions for prevention of tick bites and Lyme disease, there is a need for new tools to help reduce the risk of Lyme disease to Canadians.

A chitin deacetylase-like protein is a predominant constituent of tick peritrophic membrane that influences the persistence of Lyme disease pathogens within the vector.

PubMed

Kariu, Toru; Smith, Alexis; Yang, Xiuli; Pal, Utpal

2013-01-01

Ixodes scapularis is the specific arthropod vector for a number of globally prevalent infections, including Lyme disease caused by the bacterium Borrelia burgdorferi. A feeding-induced and acellular epithelial barrier, known as the peritrophic membrane (PM) is detectable in I. scapularis. However, whether or how the PM influences the persistence of major tick-borne pathogens, such as B. burgdorferi, remains largely unknown. Mass spectrometry-based proteome analyses of isolated PM from fed ticks revealed that the membrane contains a few detectable proteins, including a predominant and immunogenic 60 kDa protein with homology to arthropod chitin deacetylase (CDA), herein termed I. scapularis CDA-like protein or IsCDA. Although IsCDA is primarily expressed in the gut and induced early during tick feeding, its silencing via RNA interference failed to influence either the occurrence of the PM or spirochete persistence, suggesting a redundant role of IsCDA in tick biology and host-pathogen interaction. However, treatment of ticks with antibodies against IsCDA, one of the most predominant protein components of PM, affected B. burgdorferi survival, significantly augmenting pathogen levels within ticks but without influencing the levels of total gut bacteria. These studies suggested a preferential role of tick PM in limiting persistence of B. burgdorferi within the vector. Further understanding of the mechanisms by which vector components contribute to pathogen survival may help the development of new strategies to interfere with the infection.

Parasites of domestic and wild animals in South Africa. L. Ixodid ticks infesting horses and donkeys.

PubMed

Horak, Ivan G; Heyne, Heloise; Halajian, Ali; Booysen, Shalaine; Smit, Willem J

2017-02-28

The aim of the study was to determine the species spectrum of ixodid ticks that infest horses and donkeys in South Africa and to identify those species that act as vectors of disease to domestic livestock. Ticks were collected opportunistically from 391 horses countrywide by their owners or grooms, or by veterinary students and staff at the Faculty of Veterinary Science, University of Pretoria. Ticks were also collected from 76 donkeys in Limpopo Province, 2 in Gauteng Province and 1 in North West province. All the ticks were identified by means of a stereoscopic microscope. Horses were infested with 17 tick species, 72.1% with Rhipicephalus evertsi evertsi, 19.4% with Amblyomma hebraeum and 15.6% with Rhipicephalus decoloratus. Rhipicephalus evertsi evertsi was recovered from horses in all nine provinces of South Africa and R. decoloratus in eight provinces. Donkeys were infested with eight tick species, and 81.6% were infested with R. evertsi evertsi, 23.7% with A. hebraeum and 10.5% with R. decoloratus. Several tick species collected from the horses and donkeys are the vectors of economically important diseases of livestock. Rhipicephalus evertsi evertsi is the vector of Theileria equi, the causative organism of equine piroplasmosis. It also transmits Anaplasma marginale, the causative organism of anaplasmosis in cattle. Amblyomma hebraeum is the vector of Ehrlichia ruminantium, the causative organism of heartwater in cattle, sheep and goats, whereas R. decoloratus transmits Babesia bigemina, the causative organism of babesiosis in cattle.

Identification and molecular characterization of spotted fever group rickettsiae in ticks collected from farm ruminants in Lebanon.

PubMed

Fernández de Mera, Isabel G; Blanda, Valeria; Torina, Alessandra; Dabaja, Mayssaa Fawaz; El Romeh, Ali; Cabezas-Cruz, Alejandro; de la Fuente, José

2018-01-01

Tick-borne diseases have become a world health concern, emerging with increasing incidence in recent decades. Spotted fever group (SFG) rickettsiae are tick-borne pathogens recognized as important agents of human tick-borne diseases worldwide. In this study, 88 adult ticks from the species Hyalomma anatolicum, Rhipicephalus annulatus, Rh. bursa, Rh. sanguineus sensu lato, and Rh. turanicus, were collected from farm ruminants in Lebanon, and SFG rickettsiae were molecularly identified and characterized in these ticks. The screening showed a prevalence of 68% for Rickettsia spp., including the species R. aeschlimannii, R. africae, R. massiliae and Candidatus R. barbariae, the latter considered an emerging member of the SFG rickettsiae. These findings contribute to a better knowledge of the distribution of these pathogens and demonstrate that SFG rickettsiae with public health relevance are found in ticks collected in Lebanon, where the widespread distribution of tick vectors and possible livestock animal hosts in contact with humans may favor transmission to humans. Few reports exist for some of the tick species identified here as being infected with SFG Rickettsia. Some of these tick species are proven vectors of the hosted rickettsiae, although this information is unknown for other of these species. Therefore, these results suggested further investigation on the vector competence of the tick species with unknown role in transmission of some of the pathogens identified in this study. Copyright © 2017 Elsevier GmbH. All rights reserved.

Toxicity and repellency of plant essential oils against the arthropod disease vectors Phlebotomus papatasi and Ixodes scapularis

USDA-ARS?s Scientific Manuscript database

The sand fly Phlebotomus papatasi is an important blood feeder and the main vector of the trypanosomatid protozoa Leishmania major, which causes leishmaniasis in parts of the Afro-Eurasian region. The black- legged tick Ixodes scapularis is the primary tick vector of the bacterium Borrelia burgdorfe...

Invasive potential of cattle fever ticks in the southern United States

PubMed Central

2014-01-01

Abstract' Background For >100 years cattle production in the southern United States has been threatened by cattle fever. It is caused by an invasive parasite-vector complex that includes the protozoan hemoparasites Babesia bovis and B. bigemina, which are transmitted among domestic cattle via Rhipicephalus tick vectors of the subgenus Boophilus. In 1906 an eradication effort was started and by 1943 Boophilus ticks had been confined to a narrow tick eradication quarantine area (TEQA) along the Texas-Mexico border. However, a dramatic increase in tick infestations in areas outside the TEQA over the last decade suggests these tick vectors may be poised to re-invade the southern United States. We investigated historical and potential future distributions of climatic habitats of cattle fever ticks to assess the potential for a range expansion. Methods We built robust spatial predictions of habitat suitability for the vector species Rhipicephalus (Boophilus) microplus and R. (B.) annulatus across the southern United States for three time periods: 1906, present day (2012), and 2050. We used analysis of molecular variance (AMOVA) to identify persistent tick occurrences and analysis of bias in the climate proximate to these occurrences to identify key environmental parameters associated with the ecology of both species. We then used ecological niche modeling algorithms GARP and Maxent to construct models that related known occurrences of ticks in the TEQA during 2001–2011 with geospatial data layers that summarized important climate parameters at all three time periods. Results We identified persistent tick infestations and specific climate parameters that appear to be drivers of ecological niches of the two tick species. Spatial models projected onto climate data representative of climate in 1906 reproduced historical pre-eradication tick distributions. Present-day predictions, although constrained to areas near the TEQA, extrapolated well onto climate projections for 2050. Conclusions Our models indicate the potential for range expansion of climate suitable for survival of R. microplus and R. annulatus in the southern United States by mid-century, which increases the risk of reintroduction of these ticks and cattle tick fever into major cattle producing areas. PMID:24742062

Potential role of ticks as vectors of bluetongue virus.

PubMed

Bouwknegt, Chantal; van Rijn, Piet A; Schipper, Jacqueline J M; Hölzel, Dennis; Boonstra, Jan; Nijhof, Ard M; van Rooij, Eugène M A; Jongejan, Frans

2010-10-01

When the first outbreak of bluetongue virus serotype 8 (BTV8) was recorded in North-West Europe in August 2006 and renewed outbreaks occurred in the summer of 2007 and again in 2008, the question was raised how the virus survived the winter. Since most adult Culicoides vector midges are assumed not to survive the northern European winter, and transovarial transmission in Culicoides is not recorded, we examined the potential vector role of ixodid and argasid ticks for bluetongue virus. Four species of ixodid ticks (Ixodes ricinus, Ixodes hexagonus, Dermacentor reticulatus and Rhipicephalus bursa) and one soft tick species, Ornithodoros savignyi, ingested BTV8-containing blood either through capillary feeding or by feeding on artificial membranes. The virus was taken up by the ticks and was found to pass through the gut barrier and spread via the haemolymph into the salivary glands, ovaries and testes, as demonstrated by real-time reverse transcriptase PCR (PCR-test). BTV8 was detected in various tissues of ixodid ticks for up to 21 days post feeding and in Ornithodoros ticks for up to 26 days. It was found after moulting in adult Ixodes hexagonus and was also able to pass through the ovaries into the eggs of an Ornithodoros savignyi tick. This study demonstrates that ticks can become infected with bluetongue virus serotype 8. The transstadial passage in hard ticks and transovarial passage in soft ticks suggest that ticks have potential vectorial capacity for bluetongue virus. Further studies are required to investigate transmission from infected ticks to domestic livestock. This route of transmission could provide an additional clue in the unresolved mystery of the epidemiology of Bluetongue in Europe by considering ticks as a potential overwintering mechanism for bluetongue virus.

Potential role of ticks as vectors of bluetongue virus

PubMed Central

Bouwknegt, Chantal; van Rijn, Piet A.; Schipper, Jacqueline J. M.; Hölzel, Dennis; Boonstra, Jan; Nijhof, Ard M.; van Rooij, Eugène M. A.

2010-01-01

When the first outbreak of bluetongue virus serotype 8 (BTV8) was recorded in North-West Europe in August 2006 and renewed outbreaks occurred in the summer of 2007 and again in 2008, the question was raised how the virus survived the winter. Since most adult Culicoides vector midges are assumed not to survive the northern European winter, and transovarial transmission in Culicoides is not recorded, we examined the potential vector role of ixodid and argasid ticks for bluetongue virus. Four species of ixodid ticks (Ixodes ricinus, Ixodes hexagonus, Dermacentor reticulatus and Rhipicephalus bursa) and one soft tick species, Ornithodoros savignyi, ingested BTV8-containing blood either through capillary feeding or by feeding on artificial membranes. The virus was taken up by the ticks and was found to pass through the gut barrier and spread via the haemolymph into the salivary glands, ovaries and testes, as demonstrated by real-time reverse transcriptase PCR (PCR-test). BTV8 was detected in various tissues of ixodid ticks for up to 21 days post feeding and in Ornithodoros ticks for up to 26 days. It was found after moulting in adult Ixodes hexagonus and was also able to pass through the ovaries into the eggs of an Ornithodoros savignyi tick. This study demonstrates that ticks can become infected with bluetongue virus serotype 8. The transstadial passage in hard ticks and transovarial passage in soft ticks suggest that ticks have potential vectorial capacity for bluetongue virus. Further studies are required to investigate transmission from infected ticks to domestic livestock. This route of transmission could provide an additional clue in the unresolved mystery of the epidemiology of Bluetongue in Europe by considering ticks as a potential overwintering mechanism for bluetongue virus. PMID:20358393

Strategies for new and improved vaccines against ticks and tick-borne diseases.

PubMed

de la Fuente, J; Kopáček, P; Lew-Tabor, A; Maritz-Olivier, C

2016-12-01

Ticks infest a variety of animal species and transmit pathogens causing disease in both humans and animals worldwide. Tick-host-pathogen interactions have evolved through dynamic processes that accommodated the genetic traits of the hosts, pathogens transmitted and the vector tick species that mediate their development and survival. New approaches for tick control are dependent on defining molecular interactions between hosts, ticks and pathogens to allow for discovery of key molecules that could be tested in vaccines or new generation therapeutics for intervention of tick-pathogen cycles. Currently, tick vaccines constitute an effective and environmentally sound approach for the control of ticks and the transmission of the associated tick-borne diseases. New candidate protective antigens will most likely be identified by focusing on proteins with relevant biological function in the feeding, reproduction, development, immune response, subversion of host immunity of the tick vector and/or molecules vital for pathogen infection and transmission. This review addresses different approaches and strategies used for the discovery of protective antigens, including focusing on relevant tick biological functions and proteins, reverse genetics, vaccinomics and tick protein evolution and interactomics. New and improved tick vaccines will most likely contain multiple antigens to control tick infestations and pathogen infection and transmission. © 2016 John Wiley & Sons Ltd.

Experimental Infection of Ornithodoros erraticus sensu stricto with Two Portuguese African Swine Fever Virus Strains. Study of Factors Involved in the Dynamics of Infection in Ticks

PubMed Central

Madeira, Sara; Hutchings, Geoff H.; Boinas, Fernando

2015-01-01

African swine fever (ASF) is a frequently devastating hemorrhagic disease of domestic pigs and wild boar and Ornithodoros erraticus sensu stricto argasid ticks are the only biological vectors of African swine fever virus (ASFV) known to occur in Europe. Recently this disease emerged in Eastern Europe and Russian Federation, showing a huge potential for a rapid spread between countries. There is some risk of re-emergence of ASF in the countries where these ticks exist, that can contribute for the persistence of infection and compromise control measures. In this study we aimed to identify factors that determine the probability of infection and its dynamics in the tick vector Ornithodoros erraticus sensu stricto, with two Portuguese strains of ASFV. Our results suggest that these ticks have a high likelihood of excreting the two haemadsorbing ASF viruses of different host origins and that, in field surveys, the analysis of adults and 5th nymphal stage can provide the best chance of detecting virus infection. The results also indicate that infection of pigs with highly virulent ASF viruses will promote higher rates of infection and a higher likelihood for virus excretion by ticks. Nevertheless, there is also a risk, although lower, that ticks can become infected on pigs that have overcome the acute phase of infection, which was simulated in our study by membrane feeding ticks with low titres of virus. We believe these results can be valuable in designing and interpreting the results of ASF control programmes, and future work can also be undertaken as our dataset is released under open access, to perform studies in risk assessment for ASFV persistence in a region where O. erraticus sensu stricto ticks are present. PMID:26366570

Anaplasma phagocytophilum Infection Subverts Carbohydrate Metabolic Pathways in the Tick Vector, Ixodes scapularis.

PubMed

Cabezas-Cruz, Alejandro; Alberdi, Pilar; Valdés, James J; Villar, Margarita; de la Fuente, José

2017-01-01

The obligate intracellular pathogen, Anaplasma phagocytophilum , is the causative agent of human, equine, and canine granulocytic anaplasmosis and tick-borne fever (TBF) in ruminants. A. phagocytophilum has become an emerging tick-borne pathogen in the United States, Europe, Africa, and Asia, with increasing numbers of infected people and animals every year. It has been recognized that intracellular pathogens manipulate host cell metabolic pathways to increase infection and transmission in both vertebrate and invertebrate hosts. However, our current knowledge on how A. phagocytophilum affect these processes in the tick vector, Ixodes scapularis is limited. In this study, a genome-wide search for components of major carbohydrate metabolic pathways was performed in I. scapularis ticks for which the genome was recently published. The enzymes involved in the seven major carbohydrate metabolic pathways glycolysis, gluconeogenesis, pentose phosphate, tricarboxylic acid cycle (TCA), glyceroneogenesis, and mitochondrial oxidative phosphorylation and β-oxidation were identified. Then, the available transcriptomics and proteomics data was used to characterize the mRNA and protein levels of I. scapularis major carbohydrate metabolic pathway components in response to A. phagocytophilum infection of tick tissues and cultured cells. The results showed that major carbohydrate metabolic pathways are conserved in ticks. A. phagocytophilum infection inhibits gluconeogenesis and mitochondrial metabolism, but increases the expression of glycolytic genes. A model was proposed to explain how A. phagocytophilum could simultaneously control tick cell glucose metabolism and cytoskeleton organization, which may be achieved in part by up-regulating and stabilizing hypoxia inducible factor 1 alpha in a hypoxia-independent manner. The present work provides a more comprehensive view of the major carbohydrate metabolic pathways involved in the response to A. phagocytophilum infection in ticks, and provides the basis for further studies to develop novel strategies for the control of granulocytic anaplasmosis.

Experimental Infection of Ornithodoros erraticus sensu stricto with Two Portuguese African Swine Fever Virus Strains. Study of Factors Involved in the Dynamics of Infection in Ticks.

PubMed

Ribeiro, Rita; Otte, Joachim; Madeira, Sara; Hutchings, Geoff H; Boinas, Fernando

2015-01-01

African swine fever (ASF) is a frequently devastating hemorrhagic disease of domestic pigs and wild boar and Ornithodoros erraticus sensu stricto argasid ticks are the only biological vectors of African swine fever virus (ASFV) known to occur in Europe. Recently this disease emerged in Eastern Europe and Russian Federation, showing a huge potential for a rapid spread between countries. There is some risk of re-emergence of ASF in the countries where these ticks exist, that can contribute for the persistence of infection and compromise control measures. In this study we aimed to identify factors that determine the probability of infection and its dynamics in the tick vector Ornithodoros erraticus sensu stricto, with two Portuguese strains of ASFV. Our results suggest that these ticks have a high likelihood of excreting the two haemadsorbing ASF viruses of different host origins and that, in field surveys, the analysis of adults and 5th nymphal stage can provide the best chance of detecting virus infection. The results also indicate that infection of pigs with highly virulent ASF viruses will promote higher rates of infection and a higher likelihood for virus excretion by ticks. Nevertheless, there is also a risk, although lower, that ticks can become infected on pigs that have overcome the acute phase of infection, which was simulated in our study by membrane feeding ticks with low titres of virus. We believe these results can be valuable in designing and interpreting the results of ASF control programmes, and future work can also be undertaken as our dataset is released under open access, to perform studies in risk assessment for ASFV persistence in a region where O. erraticus sensu stricto ticks are present.

Europe-Wide Meta-Analysis of Borrelia burgdorferi Sensu Lato Prevalence in Questing Ixodes ricinus Ticks.

PubMed

Strnad, Martin; Hönig, Václav; Růžek, Daniel; Grubhoffer, Libor; Rego, Ryan O M

2017-08-01

Lyme borreliosis is the most common zoonotic disease transmitted by ticks in Europe and North America. Despite having multiple tick vectors, the causative agent, Borrelia burgdorferi sensu lato , is vectored mainly by Ixodes ricinus in Europe. In the present study, we aimed to review and summarize the existing data published from 2010 to 2016 concerning the prevalence of B. burgdorferi sensu lato spirochetes in questing I. ricinus ticks. The primary focus was to evaluate the infection rate of these bacteria in ticks, accounting for tick stage, adult tick gender, region, and detection method, as well as to investigate any changes in prevalence over time. The data obtained were compared to the findings of a previous metastudy. The literature search identified data from 23 countries, with 115,028 ticks, in total, inspected for infection with B. burgdorferi sensu lato We showed that the infection rate was significantly higher in adults than in nymphs and in females than in males. We found significant differences between European regions, with the highest infection rates in Central Europe. The most common genospecies were B. afzelii and B. garinii , despite a negative correlation of their prevalence rates. No statistically significant differences were found among the prevalence rates determined by conventional PCR, nested PCR, and real-time PCR. IMPORTANCE Borrelia burgdorferi sensu lato is a pathogenic bacterium whose clinical manifestations are associated with Lyme borreliosis. This vector-borne disease is a major public health concern in Europe and North America and may lead to severe arthritic, cardiovascular, and neurological complications if left untreated. Although pathogen prevalence is considered an important predictor of infection risk, solitary isolated data have only limited value. Here we provide summarized information about the prevalence of B. burgdorferi sensu lato spirochetes among host-seeking Ixodes ricinus ticks, the principal tick vector of borreliae in Europe. We compare the new results with previously published data in order to evaluate any changing trends in tick infection. Copyright © 2017 American Society for Microbiology.

Tick-Borne Zoonoses in the United States: Persistent and Emerging Threats to Human Health

PubMed Central

Eisen, Rebecca J.; Kugeler, Kiersten J.; Eisen, Lars; Beard, Charles B.; Paddock, Christopher D.

2017-01-01

In the United States, ticks transmit the greatest diversity of arthropod-borne pathogens and are responsible for the most cases of all vector-borne diseases. In recent decades, the number of reported cases of notifiable tick-borne diseases has steadily increased, geographic distributions of many ticks and tick-borne diseases have expanded, and new tick-borne disease agents have been recognized. In this review, we (1) describe the known disease agents associated with the most commonly human-biting ixodid ticks, (2) review the natural histories of these ticks and their associated pathogens, (3) highlight spatial and temporal changes in vector tick distributions and tick-borne disease occurrence in recent decades, and (4) identify knowledge gaps and barriers to more effective prevention of tick-borne diseases. We describe 12 major tick-borne diseases caused by 15 distinct disease agents that are transmitted by the 8 most commonly human-biting ixodid ticks in the United States. Notably, 40% of these pathogens were described within the last two decades. Our assessment highlights the importance of animal studies to elucidate how tick-borne pathogens are maintained in nature, as well as advances in molecular detection of pathogens which has led to the discovery of several new tick-borne disease agents. PMID:28369515

A Tick Vector Transmission Model of Monocytotropic Ehrlichiosis

PubMed Central

Saito, Tais Berelli; Walker, David H.

2015-01-01

Background. Ehrlichioses are emerging, tick-borne diseases distributed worldwide. Previously established animal models use needle inoculation as a mode of infection; however, there is limited representation of natural transmission in artificially inoculated models compared with transmission by the tick vector. The objective of this study was to develop a tick vector transmission animal model of ehrlichial infection using a human pathogen, Ehrlichia muris–like agent (EMLA). Methods. Ixodes scapularis larvae were fed on EMLA-infected mice, and after molting, infected nymphs were used to infest naive animals. Results. Ehrlichiae were acquired by 90%–100% of feeding larvae. The majority of animals fed upon by infected nymphs developed sublethal infection with 27% lethality. Bacteria disseminated to all tissues tested with greatest bacterial loads in lungs, but also spleen, lymph nodes, liver, kidneys, brain, and bone marrow. Numerous foci of cellular infiltration, mitoses, and hepatocellular death were observed in liver. Mice infected by tick transmission developed higher antiehrlichial antibody levels than needle-inoculated animals. Tick-feeding-site reactions were observed, but there was no observed difference between animals infested with infected or uninfected ticks. Conclusions. For the first time we were able to develop a tick transmission model with an Ehrlichia that is pathogenic for humans. PMID:25737562

Tick-borne protozoa

USDA-ARS?s Scientific Manuscript database

Tick-borne protozoa impose a significant health burden on humans and animals throughout the world. The virulence of tick-borne protozoa, and the geographic distribution of their tick vectors and vertebrate hosts remain in flux as they adapt to changing environmental and climatic conditions. Babesios...

Regional Disease Vector Ecology Profile: The Middle East

DTIC Science & Technology

1999-10-01

meningoencephalitis, or diphasic milk disease. Human disease of the Far Eastern subtype is usually clinically more severe in the acute phase and...bites of infected ticks or by crushing infected ticks on abraded skin. Infection can also be acquired from the consumption of raw milk or...unpasteurized milk products, usually from goats. Natural infections have been recorded in 16 species of ixodid ticks. Ixodes ricinus is the primary vector

Ixodes ricinus and Its Endosymbiont Midichloria mitochondrii: A Comparative Proteomic Analysis of Salivary Glands and Ovaries.

PubMed

Di Venere, Monica; Fumagalli, Marco; Cafiso, Alessandra; De Marco, Leone; Epis, Sara; Plantard, Olivier; Bardoni, Anna; Salvini, Roberta; Viglio, Simona; Bazzocchi, Chiara; Iadarola, Paolo; Sassera, Davide

2015-01-01

Hard ticks are hematophagous arthropods that act as vectors of numerous pathogenic microorganisms of high relevance in human and veterinary medicine. Ixodes ricinus is one of the most important tick species in Europe, due to its role of vector of pathogenic bacteria such as Borrelia burgdorferi and Anaplasma phagocytophilum, of viruses such as tick borne encephalitis virus and of protozoans as Babesia spp. In addition to these pathogens, I. ricinus harbors a symbiotic bacterium, Midichloria mitochondrii. This is the dominant bacteria associated to I. ricinus, but its biological role is not yet understood. Most M. mitochondrii symbionts are localized in the tick ovaries, and they are transmitted to the progeny. M. mitochondrii bacteria have however also been detected in the salivary glands and saliva of I. ricinus, as well as in the blood of vertebrate hosts of the tick, prompting the hypothesis of an infectious role of this bacterium. To investigate, from a proteomic point of view, the tick I. ricinus and its symbiont, we generated the protein profile of the ovary tissue (OT) and of salivary glands (SG) of adult females of this tick species. To compare the OT and SG profiles, 2-DE profiling followed by LC-MS/MS protein identification were performed. We detected 21 spots showing significant differences in the relative abundance between the OT and SG, ten of which showed 4- to 18-fold increase/decrease in density. This work allowed to establish a method to characterize the proteome of I. ricinus, and to detect multiple proteins that exhibit a differential expression profile in OT and SG. Additionally, we were able to use an immunoproteomic approach to detect a protein from the symbiont. Finally, the method here developed will pave the way for future studies on the proteomics of I. ricinus, with the goals of better understanding the biology of this vector and of its symbiont M. mitochondrii.

Infection and exposure to vector-borne pathogens in rural dogs and their ticks, Uganda.

PubMed

Proboste, Tatiana; Kalema-Zikusoka, Gladys; Altet, Laura; Solano-Gallego, Laia; Fernández de Mera, Isabel G; Chirife, Andrea D; Muro, Jesús; Bach, Ester; Piazza, Antonio; Cevidanes, Aitor; Blanda, Valeria; Mugisha, Lawrence; de la Fuente, José; Caracappa, Santo; Millán, Javier

2015-06-05

In rural parts of Africa, dogs live in close association with humans and livestock, roam freely, and usually do not receive prophylactic measures. Thus, they are a source of infectious disease for humans and for wildlife such as protected carnivores. In 2011, an epidemiological study was carried out around three conservation areas in Uganda to detect the presence and determine the prevalence of vector-borne pathogens in rural dogs and associated ticks to evaluate the risk that these pathogens pose to humans and wildlife. Serum samples (n = 105), blood smears (n = 43) and blood preserved on FTA cards (n = 38) and ticks (58 monospecific pools of Haemaphysalis leachi and Rhipicephalus praetextatus including 312 ticks from 52 dogs) were collected from dogs. Dog sera were tested by indirect immunofluorescence to detect the presence of antibodies against Rickettsia conorii and Ehrlichia canis. Antibodies against R. conorii were also examined by indirect enzyme immunoassay. Real time PCR for the detection of Rickettsia spp., Anaplasmataceae, Bartonella spp. and Babesia spp. was performed in DNA extracted from FTA cards and ticks. 99% of the dogs were seropositive to Rickettsia spp. and 29.5% to Ehrlichia spp. Molecular analyses revealed that 7.8% of the blood samples were infected with Babesia rossi, and all were negative for Rickettsia spp. and Ehrlichia spp. Ticks were infected with Rickettsia sp. (18.9%), including R. conorii and R. massiliae; Ehrlichia sp. (18.9%), including E. chaffeensis and Anaplasma platys; and B. rossi (1.7%). Bartonella spp. was not detected in any of the blood or tick samples. This study confirms the presence of previously undetected vector-borne pathogens of humans and animals in East Africa. We recommend that dog owners in rural Uganda be advised to protect their animals against ectoparasites to prevent the transmission of pathogens to humans and wildlife.

Presence of an emerging subclone of Francisella tularensis holarctica in Ixodes ricinus ticks from south-western Germany.

PubMed

Gehringer, Heike; Schacht, Erik; Maylaender, Nicole; Zeman, Ella; Kaysser, Philipp; Oehme, Rainer; Pluta, Silvia; Splettstoesser, Wolf D

2013-02-01

The zoonotic disease tularaemia is caused by the bacterial pathogen Francisella tularensis. Although the causative agent is known for 100 years, knowledge of its enzootic cycles is still rudimentary. Apart from tabanids and mosquitoes, hard ticks have been described as important vectors and potential reservoirs for F. tularensis. Available data on the incidence of human tularaemia indicate an increase in cases in the federal state of Baden-Wuerttemberg. To determine whether ticks are involved in the reported increase in F. tularensis infections in humans and wildlife in this south-western part of Germany, 916 Ixodes ricinus and 211 adult Dermacentor marginatus and D. reticulatus ticks were collected in two different locations. Screening for the presence of F. tularensis was performed by real-time PCR of the 16S rRNA gene. Of the 95 pools of I. ricinus ticks (representing 916 individual ticks), 8 tick pools (8.4%) were positive in this PCR. 30-bp deletion PCR confirmed that the F. tularensis subspecies holarctica was present. FtM24 VNTR analysis revealed that they belong to the emerging Franco-Iberian subclone group of F. tularensis holarctica. Of the 211 ticks of the genus Dermacentor, 35 randomly chosen DNAs were subjected to 16S rRNA gene screening PCR; 20 of these (57%) gave positive signals. For cluster analysis, the lpnA gene region of all Francisella-positive I. ricinus pools and 6 Dermacentor ticks with a positive reaction in the screening PCR was amplified and sequenced. In the resulting neighbour-joining tree, all Francisella-positive I. ricinus samples clustered with sequences of F. tularensis, whilst all Dermacentor tick samples clustered with FLE (Francisella-like endosymbiont) sequences. This study shows that I. ricinus ticks may serve as vectors and/or reservoirs of F. tularensis in Germany and supports the hypothesis that the state of Baden-Wuerttemberg represents an emerging endemic focus of tularaemia. Copyright © 2012 Elsevier GmbH. All rights reserved.

Impact of the experimental removal of lizards on Lyme disease risk.

PubMed

Swei, Andrea; Ostfeld, Richard S; Lane, Robert S; Briggs, Cheryl J

2011-10-07

The distribution of vector meals in the host community is an important element of understanding and predicting vector-borne disease risk. Lizards (such as the western fence lizard; Sceloporus occidentalis) play a unique role in Lyme disease ecology in the far-western United States. Lizards rather than mammals serve as the blood meal hosts for a large fraction of larval and nymphal western black-legged ticks (Ixodes pacificus--the vector for Lyme disease in that region) but are not competent reservoirs for the pathogen, Borrelia burgdorferi. Prior studies have suggested that the net effect of lizards is to reduce risk of human exposure to Lyme disease, a hypothesis that we tested experimentally. Following experimental removal of lizards, we documented incomplete host switching by larval ticks (5.19%) from lizards to other hosts. Larval tick burdens increased on woodrats, a competent reservoir, but not on deer mice, a less competent pathogen reservoir. However, most larvae failed to find an alternate host. This resulted in significantly lower densities of nymphal ticks the following year. Unexpectedly, the removal of reservoir-incompetent lizards did not cause an increase in nymphal tick infection prevalence. The net result of lizard removal was a decrease in the density of infected nymphal ticks, and therefore a decreased risk to humans of Lyme disease. Our results indicate that an incompetent reservoir for a pathogen may, in fact, increase disease risk through the maintenance of higher vector density and therefore, higher density of infected vectors.

Tick-borne infections in human and animal population worldwide

PubMed Central

Brites-Neto, José; Duarte, Keila Maria Roncato; Martins, Thiago Fernandes

2015-01-01

The abundance and activity of ectoparasites and its hosts are affected by various abiotic factors, such as climate and other organisms (predators, pathogens and competitors) presenting thus multiples forms of association (obligate to facultative, permanent to intermittent and superficial to subcutaneous) developed during long co-evolving processes. Ticks are ectoparasites widespread globally and its eco epidemiology are closely related to the environmental conditions. They are obligatory hematophagous ectoparasites and responsible as vectors or reservoirs at the transmission of pathogenic fungi, protozoa, viruses, rickettsia and others bacteria during their feeding process on the hosts. Ticks constitute the second vector group that transmit the major number of pathogens to humans and play a role primary for animals in the process of diseases transmission. Many studies on bioecology of ticks, considering the information related to their population dynamics, to the host and the environment, comes possible the application and efficiency of tick control measures in the prevention programs of vector-borne diseases. In this review were considered some taxonomic, morphological, epidemiological and clinical fundamental aspects related to the tick-borne infections that affect human and animal populations. PMID:27047089

Detection of Rickettsia and Anaplasma from hard ticks in Thailand.

PubMed

Malaisri, Premnika; Hirunkanokpun, Supanee; Baimai, Visut; Trinachartvanit, Wachareeporn; Ahantarig, Arunee

2015-12-01

We collected a total of 169 adult hard ticks and 120 nymphs from under the leaves of plants located along tourist nature trails in ten localities. The results present data examining the vector competence of ticks of different genera and the presence of Rickettsia and Anaplasma species. The ticks belonged to three genera, Amblyomma, Dermacentor, and Haemaphysalis, comprising 11 species. Rickettsia bacteria were detected at three collection sites, while Anaplasma bacteria were detected at only one site. Phylogenetic analysis revealed new rickettsia genotypes from Thailand that were closely related to Rickettsia tamurae, Rickettsia monacensis, and Rickettsia montana. This study was also the first to show that Anaplasma bacteria are found in Haemaphysalis shimoga ticks and are closely related evolutionarily to Anaplasma bovis. These results provide additional information for the geographical distribution of tick species and tick-borne bacteria in Thailand and can therefore be applied for ecotourism management. © 2015 The Society for Vector Ecology.

Genetic variation in transmission success of the Lyme borreliosis pathogen Borrelia afzelii.

PubMed

Tonetti, Nicolas; Voordouw, Maarten J; Durand, Jonas; Monnier, Séverine; Gern, Lise

2015-04-01

The vector-to-host and host-to-vector transmission steps are the two critical events that define the life cycle of any vector-borne pathogen. We expect negative genetic correlations between these two transmission phenotypes, if parasite genotypes specialized at invading the vector are less effective at infecting the vertebrate host and vice versa. We used the tick-borne bacterium Borrelia afzelii, a causative agent of Lyme borreliosis in Europe, to test whether genetic trade-offs exist between tick-to-host, systemic (host-to-tick), and a third mode of co-feeding (tick-to-tick) transmission. We worked with six strains of B. afzelii that were differentiated according to their ospC gene. We compared the three components of transmission among the B. afzelii strains using laboratory rodents as the vertebrate host and a laboratory colony of Ixodes ricinus as the tick vector. We used next generation matrix models to combine these transmission components into a single estimate of the reproductive number (R0) for each B. afzelii strain. We also tested whether these strain-specific estimates of R0 were correlated with the strain-specific frequencies in the field. We found significant genetic variation in the three transmission components among the B. afzelii strains. This is the first study to document genetic variation in co-feeding transmission for any tick-borne pathogen. We found no evidence of trade-offs as the three pairwise correlations of the transmission rates were all positive. The R0 values from our laboratory study explained 45% of the variation in the frequencies of the B. afzelii ospC strains in the field. Our study suggests that laboratory estimates of pathogen fitness can predict the distribution of pathogen strains in nature. Copyright © 2015 Elsevier GmbH. All rights reserved.

Deciphering Babesia-Vector Interactions.

PubMed

Antunes, Sandra; Rosa, Catarina; Couto, Joana; Ferrolho, Joana; Domingos, Ana

2017-01-01

Understanding host-pathogen-tick interactions remains a vitally important issue that might be better understood by basic research focused on each of the dyad interplays. Pathogens gain access to either the vector or host during tick feeding when ticks are confronted with strong hemostatic, inflammatory and immune responses. A prominent example of this is the Babesia spp.-tick-vertebrate host relationship. Babesia spp. are intraerythrocytic apicomplexan organisms spread worldwide, with a complex life cycle. The presence of transovarial transmission in almost all the Babesia species is the main difference between their life cycle and that of other piroplasmida. With more than 100 species described so far, Babesia are the second most commonly found blood parasite of mammals after trypanosomes. The prevalence of Babesia spp. infection is increasing worldwide and is currently classified as an emerging zoonosis. Babesia microti and Babesia divergens are the most frequent etiological agents associated with human babesiosis in North America and Europe, respectively. Although the Babesia -tick system has been extensively researched, the currently available prophylactic and control methods are not efficient, and chemotherapeutic treatment is limited. Studying the molecular changes induced by the presence of Babesia in the vector will not only elucidate the strategies used by the protozoa to overcome mechanical and immune barriers, but will also contribute toward the discovery of important tick molecules that have a role in vector capacity. This review provides an overview of the identified molecules involved in Babesia -tick interactions, with an emphasis on the fundamentally important ones for pathogen acquisition and transmission.

Extraction of Total Nucleic Acids From Ticks for the Detection of Bacterial and Viral Pathogens

PubMed Central

Crowder, Chris D.; Rounds, Megan A.; Phillipson, Curtis A.; Picuri, John M.; Matthews, Heather E.; Halverson, Justina; Schutzer, Steven E.; Ecker, David J.; Eshoo, Mark W.

2010-01-01

Ticks harbor numerous bacterial, protozoal, and viral pathogens that can cause serious infections in humans and domestic animals. Active surveillance of the tick vector can provide insight into the frequency and distribution of important pathogens in the environment. Nucleic-acid based detection of tick-borne bacterial, protozoan, and viral pathogens requires the extraction of both DNA and RNA (total nucleic acids) from ticks. Traditional methods for nucleic acid extraction are limited to extraction of either DNA or the RNA from a sample. Here we present a simple bead-beating based protocol for extraction of DNA and RNA from a single tick and show detection of Borrelia burgdorferi and Powassan virus from individual, infected Ixodes scapularis ticks. We determined expected yields for total nucleic acids by this protocol for a variety of adult tick species. The method is applicable to a variety of arthropod vectors, including fleas and mosquitoes, and was partially automated on a liquid handling robot. PMID:20180313

First Report of Rickettsia Identical to R. slovaca in Colony-Originated D. variabilis in the United States: Detection, Laboratory Animal Model, and Vector Competence of Ticks.

PubMed

Zemtsova, Galina E; Killmaster, Lindsay F; Montgomery, Merrill; Schumacher, Lauren; Burrows, Matt; Levin, Michael L

2016-02-01

Ticks of the genus Dermacentor are known vectors of rickettsial pathogens in both the Old World and New World. In North America, Dermacentor variabilis and D. andersoni are vectors of Rickettsia rickettsii, while in Europe, D. marginatus and D. reticulatus transmit R. slovaca and R. raoultii, respectively. Neither the presence of R. slovaca in the Americas nor the ability of American tick species to maintain this pathogen have been reported. Here we describe detection of Rickettsia genetically identical to R. slovaca in D. variabilis, its molecular characterization, assessment of pathogenicity to guinea pigs, and vector competence of D. variabilis ticks. Ticks from a laboratory colony of D. variabilis, established from wild ticks and maintained on naïve NZW rabbits, tested positive for spotted fever group (SFG) Rickettsia by PCR. Analysis of 17 kDa gltA, rpoB, ompA, ompB, and sca4 genes revealed 100% identity to R. slovaca sequences available in the GenBank. New Zealand white rabbits fed upon by infected ticks seroconverted to SFG Rickettsia. Guinea pigs inoculated with the Rickettsia culture or infested by the infected ticks developed antibodies to SFG Rickettsia. The intensity of clinical signs and immune response were dependent on dose and route of infection. The identified Rickettsia was detected in all life stages of D. variabilis ticks, confirming transstadial and transovarial transmission. Thirty-six percent of uninfected larvae co-fed with infected nymphs on guinea pigs were PCR-positive and able to pass rickettsia to at least 11.7% of molted nymphs. To our knowledge, this is a first report of identification of a European pathogen R. slovaca or a highly similar agent in the American dog tick, D. variabilis. Considering pathogenicity of R. slovaca in humans, further laboratory and field studies are warranted to assess the relevance of the above findings to the public health and epidemiology of SFG rickettsioses in the United States.

Adverse moisture events predict seasonal abundance of Lyme disease vector ticks (Ixodes scapularis)

USGS Publications Warehouse

Berger, Kathryn A.; Ginsberg, Howard S.; Dugas, Katherine D.; Hamel, Lutz H.; Mather, Thomas N.

2014-01-01

Background: Lyme borreliosis (LB) is the most commonly reported vector-borne disease in north temperate regions worldwide, affecting an estimated 300,000 people annually in the United States alone. The incidence of LB is correlated with human exposure to its vector, the blacklegged tick (Ixodes scapularis). To date, attempts to model tick encounter risk based on environmental parameters have been equivocal. Previous studies have not considered (1) the differences between relative humidity (RH) in leaf litter and at weather stations, (2) the RH threshold that affects nymphal blacklegged tick survival, and (3) the time required below the threshold to induce mortality. We clarify the association between environmental moisture and tick survival by presenting a significant relationship between the total number of tick adverse moisture events (TAMEs - calculated as microclimatic periods below a RH threshold) and tick abundance each year.Methods: We used a 14-year continuous statewide tick surveillance database and corresponding weather data from Rhode Island (RI), USA, to assess the effects of TAMEs on nymphal populations of I. scapularis. These TAMEs were defined as extended periods of time (>8 h below 82% RH in leaf litter). We fit a sigmoid curve comparing weather station data to those collected by loggers placed in tick habitats to estimate RH experienced by nymphal ticks, and compiled the number of historical TAMEs during the 14-year record.Results: The total number of TAMEs in June of each year was negatively related to total seasonal nymphal tick densities, suggesting that sub-threshold humidity episodes >8 h in duration naturally lowered nymphal blacklegged tick abundance. Furthermore, TAMEs were positively related to the ratio of tick abundance early in the season when compared to late season, suggesting that lower than average tick abundance for a given year resulted from tick mortality and not from other factors.Conclusions: Our results clarify the mechanism by which environmental moisture affects blacklegged tick populations, and offers the possibility to more accurately predict tick abundance and human LB incidence. We describe a method to forecast LB risk in endemic regions and identify the predictive role of microclimatic moisture conditions on tick encounter risk.

Transfected babesia bovis expressing a tick GST as a live vector vaccine

USDA-ARS?s Scientific Manuscript database

The Rhipicephalus microplus tick is a notorious blood-feeding ectoparasite of livestock, especially cattle, responsible for massive losses in animal production. It is the main vector for transmission of pathogenic bacteria and parasites, including Babesia bovis, an intraerythrocytic apicomplexan pro...

Tick-Borne Viruses.

PubMed

Shi, Junming; Hu, Zhihong; Deng, Fei; Shen, Shu

2018-02-01

Ticks are important vectors for the transmission of pathogens including viruses. The viruses carried by ticks also known as tick-borne viruses (TBVs), contain a large group of viruses with diverse genetic properties and are concluded in two orders, nine families, and at least 12 genera. Some members of the TBVs are notorious agents causing severe diseases with high mortality rates in humans and livestock, while some others may pose risks to public health that are still unclear to us. Herein, we review the current knowledge of TBVs with emphases on the history of virus isolation and identification, tick vectors, and potential pathogenicity to humans and animals, including assigned species as well as the recently discovered and unassigned species. All these will promote our understanding of the diversity of TBVs, and will facilitate the further investigation of TBVs in association with both ticks and vertebrate hosts.

A dityrosine network mediated by dual oxidase and peroxidase influences the persistence of Lyme disease pathogens within the vector.

PubMed

Yang, Xiuli; Smith, Alexis A; Williams, Mark S; Pal, Utpal

2014-05-02

Ixodes scapularis ticks transmit a wide array of human and animal pathogens including Borrelia burgdorferi; however, how tick immune components influence the persistence of invading pathogens remains unknown. As originally demonstrated in Caenorhabditis elegans and later in Anopheles gambiae, we show here that an acellular gut barrier, resulting from the tyrosine cross-linking of the extracellular matrix, also exists in I. scapularis ticks. This dityrosine network (DTN) is dependent upon a dual oxidase (Duox), which is a member of the NADPH oxidase family. The Ixodes genome encodes for a single Duox and at least 16 potential peroxidase proteins, one of which, annotated as ISCW017368, together with Duox has been found to be indispensible for DTN formation. This barrier influences pathogen survival in the gut, as an impaired DTN in Doux knockdown or in specific peroxidase knockdown ticks, results in reduced levels of B. burgdorferi persistence within ticks. Absence of a complete DTN formation in knockdown ticks leads to the activation of specific tick innate immune pathway genes that potentially resulted in the reduction of spirochete levels. Together, these results highlighted the evolution of the DTN in a diverse set of arthropod vectors, including ticks, and its role in protecting invading pathogens like B. burgdorferi. Further understanding of the molecular basis of tick innate immune responses, vector-pathogen interaction, and their contributions in microbial persistence may help the development of new targets for disrupting the pathogen life cycle.

Molecular biology of tick Acetylcholinesterases – a minireview

USDA-ARS?s Scientific Manuscript database

Ticks are important hematophagous arthropod ectoparasites and like mosquitoes, are vectors for a wide variety of human and animal pathogens. Ticks have significant world-wide health and economic impacts. In the U.S., major impacts include the ability of the blacklegged tick, Ixodes scapularis, to tr...

Influence of laboratory animal hosts on the life cycle of Hyalomma marginatum and implications for an in vivo transmission model for Crimean-Congo hemorrhagic fever virus

PubMed Central

Gargili, Aysen; Thangamani, Saravanan; Bente, Dennis

2013-01-01

Crimean-Congo hemorrhagic fever virus (CCHFV) is one of the most geographically widespread arboviruses and causes a severe hemorrhagic syndrome in humans. The virus circulates in nature in a vertebrate-tick cycle and ticks of the genus Hyalomma are the main vectors and reservoirs. Although the tick vector plays a central role in the maintenance and transmission of CCHFV in nature, comparatively little is known of CCHFV-tick interactions. This is mostly due to the fact that establishing tick colonies is laborious, and working with CCHFV requires a biosafety level 4 laboratory (BSL4) in many countries. Nonetheless, an in vivo transmission model is essential to understand the epidemiology of the transmission cycle of CCHFV. In addition, important parameters such as vectorial capacity of tick species, levels of infection in the host necessary to infect the tick, and aspects of virus transmission by tick bite including the influence of tick saliva, cannot be investigated any other way. Here, we evaluate the influence of different laboratory animal species as hosts supporting the life cycle of Hyalomma marginatum, a two-host tick. Rabbits were considered the host of choice for the maintenance of the uninfected colonies due to high larval attachment rates, shorter larval-nymphal feeding times, higher nymphal molting rates, high egg hatching rates, and higher conversion efficiency index (CEI). Furthermore, we describe the successful establishment of an in vivo transmission model for CCHFV in a BSL4 biocontainment setting using interferon knockout mice. This will give us a new tool to study the transmission and interaction of CCHFV with its tick vector. PMID:23971007

Stage-structured infection transmission and a spatial epidemic: a model for Lyme disease.

PubMed

Caraco, Thomas; Glavanakov, Stephan; Chen, Gang; Flaherty, Joseph E; Ohsumi, Toshiro K; Szymanski, Boleslaw K

2002-09-01

A greater understanding of the rate at which emerging disease advances spatially has both ecological and applied significance. Analyzing the spread of vector-borne disease can be relatively complex when the vector's acquisition of a pathogen and subsequent transmission to a host occur in different life stages. A contemporary example is Lyme disease. A long-lived tick vector acquires infection during the larval blood meal and transmits it as a nymph. We present a reaction-diffusion model for the ecological dynamics governing the velocity of the current epidemic's spread. We find that the equilibrium density of infectious tick nymphs (hence the risk of human disease) can depend on density-independent survival interacting with biotic effects on the tick's stage structure. The local risk of infection reaches a maximum at an intermediate level of adult tick mortality and at an intermediate rate of juvenile tick attacks on mammalian hosts. If the juvenile tick attack rate is low, an increase generates both a greater density of infectious nymphs and an increased spatial velocity. However, if the juvenile attack rate is relatively high, nymph density may decline while the epidemic's velocity still increases. Velocities of simulated two-dimensional epidemics correlate with the model pathogen's basic reproductive number (R0), but calculating R0 involves parameters of both host infection dynamics and the vector's stage-structured dynamics.

Arthropods: Vectors of Disease Agents

DTIC Science & Technology

1994-07-01

vector or glands in the tick legs. Filarid in some tick species, individuals of be passively regurgitated during worms (eg, dog heartworm) devel- which...Australia and an arthropod serves as the vector passively regurgitated during blood- Antarctica. An estimated 50 million transferring the etiologic agent...opossums, Biological ɝ More common in racoons, armadillos dogs than people Garbage, sewage, etc Mechanical NA I akwoator% %ledionc %.j. 2i, \\.I

Tick-borne rickettsial pathogens in questing ticks, removed from humans and animals in Mexico.

PubMed

Sosa-Gutierrez, Carolina G; Vargas-Sandoval, Margarita; Torres, Javier; Gordillo-Pérez, Guadalupe

2016-09-30

Tick-borne rickettsial diseases (TBRD) are commonly encountered in medical and veterinary clinical settings. The control of these diseases is difficult, requiring disruption of a complex transmission chain involving a vertebrate host and ticks. The geographical distribution of the diseases is related to distribution of the vector, which is an indicator of risk for the population. A total of 1107 were collected by tick drag from forests, ecotourism parks and hosts at 101 sites in 22 of the 32 states of Mexico. Collected ticks were placed in 1.5 mL cryovials containing 70% ethanol and were identified to species. Ticks were pooled according to location/host of collection, date of collection, sex, and stage of development. A total of 51 ticks were assayed by polymerase chain reaction (PCR) to confirm species identification using morphological methods. A total of 477 pools of ticks were assayed using PCR techniques for selected tick-borne pathogens. Anaplasma phagocytophilum was the most commonly detected pathogen (45 pools), followed by, Ehrlichia (E.) canis (42), Rickettsia (R.) rickettsii (11), E. chaffeensis (8), and R. amblyommii (1). Rhipicephalus sanguineus was the tick most frequently positive for selected pathogens. Overall, our results indicate that potential tick vectors positive for rickettsial pathogens are distributed throughout the area surveyed in Mexico.

The bacterial microbiome of dermacentor andersoni ticks influences pathogen susceptibility

USDA-ARS?s Scientific Manuscript database

Ticks are of medical and veterinary importance due to their ability to transmit pathogens to humans and animals. The Rocky Mountain wood tick, Dermacentor andersoni, is a vector of a number of pathogens, including Anaplasma marginale, which is the most widespread tick-borne pathogen of livestock. Al...

Vector and Serologic Survey for Crimean-Congo Hemorrhagic Fever Virus in Poland.

PubMed

Bażanów, Barbara A; Pacoń, Jarosław; Gadzała, Łukasz; Frącka, Agnieszka; Welz, Mirosław; Paweska, Janusz

2017-07-01

In contrast to animals, Crimean-Congo hemorrhagic fever (CCHF) causes a severe disease in humans with a high mortality rate. The etiological agent, CCHF virus (CCHFV), can be transmitted by argasid and ixodid ticks, but arachnids of the genus Hyalomma, followed by Rhipicephalus and Dermacentor serve as the major vectors of this virus. The goal of the study was to assess the epidemiological situation of CCHFV infection in cattle in south-east Poland, and survey for potential tick vector species. A total of 592 bovine blood samples from animals located in the southernmost region in Poland were tested by IgG sandwich enzyme-linked immunosorbent assay. Ticks (n = 993) from south-east Poland were collected from dogs, cats, cattle, and horses and tested by RT-PCR. All 592 serum samples were negative for IgG antibodies to CCHFV. Of the ticks collected, 125 were Dermacentor reticulatus and 868 represented Ixodes ricinus, both species are regarded as potential vectors of CCHFV. All tick samples were negative for the presence of CCHFV. Considering the zoonotic nature, public health importance, and the virus increasing spread, it was prudent to assess the seroprevalence of CCHFV in the south-east area of Poland, bordering with CCHFV endemic areas. It seems unlikely that CCHFV infection will suddenly spread in Poland, but considering the multiple possibilities of the virus introduction, serosurveys and vector biosurveillance should be conducted at regular intervals.

Bacterial community in Haemaphysalis ticks of domesticated animals from the Orang Asli communities in Malaysia.

PubMed

Khoo, Jing-Jing; Chen, Fezshin; Kho, Kai Ling; Ahmad Shanizza, Azzy Iyzati; Lim, Fang-Shiang; Tan, Kim-Kee; Chang, Li-Yen; AbuBakar, Sazaly

2016-07-01

Ticks are vectors in the transmission of many important infectious diseases in human and animals. Ticks can be readily found in the semi-forested areas such as the settlements of the indigenous people in Malaysia, the Orang Asli. There is still minimal information available on the bacterial agents associated with ticks found in Malaysia. We performed a survey of the bacterial communities associated with ticks collected from domestic animals found in two Orang Asli villages in Malaysia. We collected 62 ticks, microscopically and molecularly identified as related to Haemaphysalis wellingtoni, Haemaphysalis hystricis and Haemaphysalis bispinosa. Bacterial 16s rRNA hypervariable region (V6) amplicon libraries prepared from the tick samples were sequenced on the Ion Torrent PGM platform. We detected a total of 392 possible bacterial genera after pooling and sequencing 20 samples, indicating a diverse bacterial community profile. Dominant taxa include the potential tick endosymbiont, Coxiella. Other dominant taxa include the tick-associated pathogen, Rickettsia, and environmental bacteria such as Bacillus, Mycobacterium, Sphingomonas and Pseudomonas. Other known tick-associated bacteria were also detected, including Anaplasma, Ehrlichia, Rickettsiella and Wolbachia, albeit at very low abundance. Specific PCR was performed on selected samples to identify Rickettsia and Coxiella. Sequence of Rickettsia felis, which causes spotted fever in human and cats, was identified in one sample. Coxiella endosymbionts were detected in three samples. This study provides the baseline knowledge of the microbiome of ticks in Malaysia, focusing on tick-associated bacteria affecting the Orang Asli communities. The role of the herein found Coxiella and Rickettsia in tick physiology or disease transmission merits further investigation. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

Establishment of an Artificial Tick Feeding System to Study Theileria lestoquardi Infection

PubMed Central

Tajeri, Shahin; Razmi, Gholamreza; Haghparast, Alireza

2016-01-01

The establishment of good experimental models for Theileria sp. infection is important for theileriosis research. Routinely, infection of ticks is accomplished by feeding on parasite-infected animals (sheep, cows and horses), which raises practical and ethical problems, driving the search for alternative methods of tick infection. Artificial tick feeding systems are based mainly on rearing ticks on host-derived or hand-made artificial membranes. We developed a modified feeding assay for infecting nymphal stages of Hyalomma anatolicum ticks with Theileria lestoquardi, a highly pathogenic parasite of sheep. We compared two different membranes: an artificial silicone membrane and a natural alternative using mouse skin. We observed high attachment rates with mouse skin, whereas in vitro feeding of H. anatolicum nymphs on silicone membranes was unsuccessful. We could infect H. anatolicum nymphs with T. lestoquardi and the emerging adult ticks transmitted infective parasites to sheep. In contrast, similar infections with Rhipicephalus bursa, a representative tick with short mouth-parts that was proposed as a vector for T. lestoquardi, appeared not to be a competent vector tick species. This is the first report of an experimentally controlled infection of H. anatolicum with T. lestoquardi and opens avenues to explore tick-parasite dynamics in detail. PMID:28036364

Ticks and Tick-Borne Infections: Complex Ecology, Agents, and Host Interactions.

PubMed

Wikel, Stephen K

2018-06-20

Ticks transmit the most diverse array of infectious agents of any arthropod vector. Both ticks and the microbes they transmit are recognized as significant threats to human and veterinary public health. This article examines the potential impacts of climate change on the distribution of ticks and the infections they transmit; the emergence of novel tick-borne pathogens, increasing geographic range and incidence of tick-borne infections; and advances in the characterization of tick saliva mediated modulation of host defenses and the implications of those interactions for transmission, establishment, and control of tick infestation and tick-borne infectious agents.

Ticks

USGS Publications Warehouse

Ginsberg, H.S.; Faulde, M.K.

2008-01-01

The most common vector-borne diseases in both Europe and North America are transmitted by ticks. Lyme borreliosis (LB), a tick-borne bacterial zoonosis, is the most highly prevalent. Other important tick-borne diseases include TBE (tick-borne encephalitis) and Crimean-Congo haemorrhagic fever in Europe, Rocky Mountain spotted fever (RMSF) in North America, and numerous less common tick-borne bacterial, viral, and protozoan diseases on both continents. The major etiological agent of LB is Borrelia burgdorferi in North America, while in Europe several related species of Borrelia can also cause human illness. These Borrelia genospecies differ in clinical manifestations, ecology (for example, some have primarily avian and others primarily mammalian reservoirs), and transmission cycles, so the epizootiology of LB is more complex in Europe than in North America. Ticks dwell predominantly in woodlands and meadows, and in association with animal hosts, with only limited colonization of human dwellings by a few species. Therefore, suburbanization has contributed substantially to the increase in tick-borne disease transmission in North America by fostering increased exposure of humans to tick habitat. The current trend toward suburbanization in Europe could potentially result in similar increases in transmission of tick-borne diseases. Incidence of tick-borne diseases can be lowered by active public education campaigns, targeted at the times and places of greatest potential for encounter between humans and infected ticks. Similarly, vaccines (e.g., against TBE) are most effective when made available to people at greatest risk, and for high-prevalence diseases such as LB. Consultation with vector-borne disease experts during the planning stages of new human developments can minimize the potential for residents to encounter infected ticks (e.g., by appropriate dwelling and landscape design). Furthermore, research on tick vectors, pathogens, transmission ecology, and on geographic distribution, spread, and management of tick-borne diseases can lead to innovative and improved methods to lower the incidence of these diseases. Surveillance programs to monitor the distribution and spread of ticks, associated pathogens, and their reservoirs, can allow better-targeted management efforts, and provide data to assess effectiveness and to improve management programs.

Tick repellents and acaricides of botanical origin: a green roadmap to control tick-borne diseases?

PubMed

Benelli, Giovanni; Pavela, Roman; Canale, Angelo; Mehlhorn, Heinz

2016-07-01

Arthropods are dangerous vectors of agents of deadly diseases, which may hit as epidemics or pandemics in the increasing world population of humans and animals. Among them, ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide. Thus, the effective and eco-friendly control of tick vectors in a constantly changing environment is a crucial challenge. A number of novel routes have been attempted to prevent and control tick-borne diseases, including the development of (i) vaccines against viruses vectored by ticks; (ii) pheromone-based control tools, with special reference to the "lure and kill" techniques; (iii) biological control programmes relying on ticks' natural enemies and pathogens; and (iv) the integrated pest management practices aimed at reducing tick interactions with livestock. However, the extensive employment of acaricides and tick repellents still remains the two most effective and ready-to-use strategies. Unfortunately, the first one is limited by the rapid development of resistance in ticks, as well as by serious environmental concerns. On the other hand, the exploitation of plants as sources of effective tick repellents is often promising. Here, we reviewed current knowledge concerning the effectiveness of plant extracts as acaricides or repellents against tick vectors of public health importance, with special reference to Ixodes ricinus, Ixodes persulcatus, Amblyomma cajennense, Haemaphysalis bispinosa, Haemaphysalis longicornis, Hyalomma anatolicum, Hyalomma marginatum rufipes, Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) microplus, Rhipicephalus pulchellus, Rhipicephalus sanguineus and Rhipicephalus turanicus. Eighty-three plant species from 35 botanical families were selected. The most frequent botanical families exploited as sources of acaricides and repellents against ticks were Asteraceae (15 % of the selected studies), Fabaceae (9 %), Lamiaceae (10 %), Meliaceae (5 %), Solanaceae (6 %) and Verbenaceae (5 %). Regression equation analyses showed that the literature grew by approximately 20 % per year (period: 2005-2015). Lastly, in the final section, insights for future research are discussed. We focused on some caveats for future data collection and analysis. Current critical points mainly deal with (a) not uniform methods used, which prevent proper comparison of the results; (b) inaccurate tested concentrations, frequently 100 % concentration corresponded to the gross extract, where the exact amounts of extracted substances are unknown; and (c) not homogeneous size of tested tick instars and species. Overall, the knowledge summarized in this review may be helpful for comparative screening among extensive numbers of plant-borne preparations, in order to develop newer and safer tick control tools.

Tick receptor for outer surface protein A from Ixodes ricinus — the first intrinsically disordered protein involved in vector-microbe recognition

NASA Astrophysics Data System (ADS)

Urbanowicz, Anna; Lewandowski, Dominik; Szpotkowski, Kamil; Figlerowicz, Marek

2016-04-01

The tick receptor for outer surface protein A (TROSPA) is the only identified factor involved in tick gut colonization by various Borrelia species. TROSPA is localized in the gut epithelium and can recognize and bind the outer surface bacterial protein OspA via an unknown mechanism. Based on earlier reports and our latest observations, we considered that TROSPA would be the first identified intrinsically disordered protein (IDP) involved in the interaction between a vector and a pathogenic microbe. To verify this hypothesis, we performed structural studies of a TROSPA mutant from Ixodes ricinus using both computational and experimental approaches. Irrespective of the method used, we observed that the secondary structure content of the TROSPA polypeptide chain is low. In addition, the collected SAXS data indicated that this protein is highly extended and exists in solution as a set of numerous conformers. These features are all commonly considered hallmarks of IDPs. Taking advantage of our SAXS data, we created structural models of TROSPA and proposed a putative mechanism for the TROSPA-OspA interaction. The disordered nature of TROSPA may explain the ability of a wide spectrum of Borrelia species to colonize the tick gut.

Anaplasma marginale actively modulates vacuolar maturation during intracellular infection of its tick vector dermacentor andersoni

USDA-ARS?s Scientific Manuscript database

Tick-borne transmission of bacterial pathogens in the Order Rickettsiales is responsible for a diversity of infectious diseases, many of them severe, in both humans and animals. Transmission dynamics differ among these pathogens and are reflected in the pathogen-vector interaction. Anaplasma margina...

Invasive Potential of Cattle Fever Ticks in the Southern United States

USDA-ARS?s Scientific Manuscript database

For >100 years cattle production in the southern United States has been threatened by cattle fever. It is caused by an invasive parasite-vector complex that includes the protozoan hemoparasites Babesia bovis and B. bigemina, which are transmitted among domestic cattle via Rhipicephalus tick vectors ...

Rickettsia species in human-parasitizing ticks in Greece.

PubMed

Papa, Anna; Xanthopoulou, Kyriaki; Kotriotsiou, Tzimoula; Papaioakim, Miltiadis; Sotiraki, Smaragda; Chaligiannis, Ilias; Maltezos, Efstratios

2016-05-01

Ticks serve as vectors and reservoirs for a variety of bacterial, viral and protozoan pathogens affecting humans and animals. Unusual increased tick aggressiveness was observed in 2008-2009 in northeastern Greece. The aim of the study was to check ticks removed from persons during 2009 for infection with Rickettsia species. A total of 159 ticks were removed from 147 persons who sought medical advice in a hospital. Tick identification was performed morphologically using taxonomic keys. DNA was extracted from each individual tick and a PCR assay targeting the rickettsial outer membrane protein A gene of Rickettsia spp. was applied. Most of the adult ticks (132/153, 86.3%) were Rhipicephalus sanguineus. Rickettsiae were detected in 23 of the 153 (15.0%) adult ticks. Five Rickettsiae species were identified: R. aeschlimannii, R. africae (n=6), R. massilae (4), R. monacensis (1), and Candidatus R. barbariae (1). To our knowledge, this is the first report of R. africae, R. monacensis, and Candidatus R. barbariae in Greece. Several Rickettsia species were identified in ticks removed from humans in Greece, including those that are prevalent in northern and southern latitudes. © The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Lyme disease bacterium does not affect attraction to rodent odour in the tick vector.

PubMed

Berret, Jérémy; Voordouw, Maarten Jeroen

2015-04-28

Vector-borne pathogens experience a conflict of interest when the arthropod vector chooses a vertebrate host that is incompetent for pathogen transmission. The qualitative manipulation hypothesis suggests that vector-borne pathogens can resolve this conflict in their favour by manipulating the host choice behaviour of the arthropod vector. European Lyme disease is a model system for studying this conflict because Ixodes ricinus is a generalist tick species that vectors Borrelia pathogens that are specialized on different classes of vertebrate hosts. Avian specialists like B. garinii cannot survive in rodent reservoir hosts and vice versa for rodent specialists like B. afzelii. The present study tested whether Borrelia genospecies influenced the attraction of field-collected I. ricinus nymphs to rodent odours. Nymphs were significantly attracted to questing perches that had been scented with mouse odours. However, there was no difference in questing behaviour between nymphs infected with rodent- versus bird-specialized Borrelia genospecies. Our study suggests that the tick, and not the pathogen, controls the early stages of host choice behaviour.

Multiple pruritic papules from lone star tick larvae bites.

PubMed

Fisher, Emily J; Mo, Jun; Lucky, Anne W

2006-04-01

Ticks are the second most common vectors of human infectious diseases in the world. In addition to their role as vectors, ticks and their larvae can also produce primary skin manifestations. Infestation by the larvae of ticks is not commonly recognized, with only 3 cases reported in the literature. The presence of multiple lesions and partially burrowed 6-legged tick larvae can present a diagnostic challenge for clinicians. We describe a 51-year-old healthy woman who presented to our clinic with multiple erythematous papules and partially burrowed organisms 5 days after exposure to a wooded area in southern Kentucky. She was treated with permethrin cream and the lesions resolved over the following 3 weeks without sequelae. The organism was later identified as the larva of Amblyomma species, the lone star tick. Multiple pruritic papules can pose a diagnostic challenge. The patient described herein had an unusually large number of pruritic papules as well as tick larvae present on her skin. Recognition of lone star tick larvae as a cause of multiple bites may be helpful in similar cases.

Brave New Worlds: The Expanding Universe of Lyme Disease.

PubMed

Stone, Brandee L; Tourand, Yvonne; Brissette, Catherine A

2017-09-01

Projections around the globe suggest an increase in tick-vectored disease incidence and distribution, and the potential for emergence of novel tick-borne pathogens. Lyme disease is the most common reported tick-borne illness in the Unites States and is prevalent throughout much of central Europe. In recent years, the worldwide burden of Lyme disease has increased and extended into regions and countries where the disease was not previously reported. In this review, we discuss the trends for increasing Lyme disease, and examine the factors driving Lyme disease expansion, including the effect of climate change on the spread of vector Ixodid ticks and reservoir hosts; and the impacts of increased awareness on disease reporting and diagnosis. To understand the growing threat of Lyme disease, we need to study the interplay between vector, reservoir, and pathogen. In addition, we need to understand the contributions of climate conditions to changes in disease risk.

Public-private partnership experience enabling translational research for anti-tick vaccine used in integrated Rhipicephalus (Boophilus) microplus and R. annulatus tick eradication in the United States of America

USDA-ARS?s Scientific Manuscript database

Rhipicephalus (Boophilus) microplus and R. annulatus are invasive tick species and vectors of microbes causing bovine babesiosis and anaplasmosis that were declared eradicated from the United States of America in 1943 through efforts of the Cattle Fever Tick Eradication Program. These tick disease v...

Ecology, biology and distribution of spotted-fever tick vectors in Brazil.

PubMed

Szabó, Matias P J; Pinter, Adriano; Labruna, Marcelo B

2013-01-01

Spotted-fever-caused Rickettsia rickettsii infection is in Brazil the major tick-borne zoonotic disease. Recently, a second and milder human rickettsiosis caused by an agent genetically related to R. parkeri was discovered in the country (Atlantic rainforest strain). Both diseases clearly have an ecological background linked to a few tick species and their environment. Capybaras (Hydrochoerus hydrochaeris) and Amblyomma cajennense ticks in urban and rural areas close to water sources are the main and long-known epidemiological feature behind R. rickettsii-caused spotted-fever. Unfortunately, this ecological background seems to be increasing in the country and disease spreading may be foreseen. Metropolitan area of São Paulo, the most populous of the country, is embedded in Atlantic rainforest that harbors another important R. rickettsii vector, the tick Amblyomma aureolatum. Thus, at the city-forest interface, dogs carry infected ticks to human dwellings and human infection occurs. A role for R. rickettsii vectoring to humans of a third tick species, Rhipicephalus sanguineus in Brazil, has not been proven; however, there is circumstantial evidence for that. A R. parkeri-like strain was found in A. ovale ticks from Atlantic rainforest and was shown to be responsible for a milder febrile human disease. Rickettsia-infected A. ovale ticks are known to be spread over large areas along the Atlantic coast of the country, and diagnosis of human infection is increasing with awareness and proper diagnostic tools. In this review, ecological features of the tick species mentioned, and that are important for Rickettsia transmission to humans, are updated and discussed. Specific knowledge gaps in the epidemiology of such diseases are highlighted to guide forthcoming research.

Ecology, biology and distribution of spotted-fever tick vectors in Brazil

PubMed Central

Szabó, Matias P. J.; Pinter, Adriano; Labruna, Marcelo B.

2013-01-01

Spotted-fever-caused Rickettsia rickettsii infection is in Brazil the major tick-borne zoonotic disease. Recently, a second and milder human rickettsiosis caused by an agent genetically related to R. parkeri was discovered in the country (Atlantic rainforest strain). Both diseases clearly have an ecological background linked to a few tick species and their environment. Capybaras (Hydrochoerus hydrochaeris) and Amblyomma cajennense ticks in urban and rural areas close to water sources are the main and long-known epidemiological feature behind R. rickettsii-caused spotted-fever. Unfortunately, this ecological background seems to be increasing in the country and disease spreading may be foreseen. Metropolitan area of São Paulo, the most populous of the country, is embedded in Atlantic rainforest that harbors another important R. rickettsii vector, the tick Amblyomma aureolatum. Thus, at the city–forest interface, dogs carry infected ticks to human dwellings and human infection occurs. A role for R. rickettsii vectoring to humans of a third tick species, Rhipicephalus sanguineus in Brazil, has not been proven; however, there is circumstantial evidence for that. A R. parkeri-like strain was found in A. ovale ticks from Atlantic rainforest and was shown to be responsible for a milder febrile human disease. Rickettsia-infected A. ovale ticks are known to be spread over large areas along the Atlantic coast of the country, and diagnosis of human infection is increasing with awareness and proper diagnostic tools. In this review, ecological features of the tick species mentioned, and that are important for Rickettsia transmission to humans, are updated and discussed. Specific knowledge gaps in the epidemiology of such diseases are highlighted to guide forthcoming research. PMID:23875178

Ectoparasites of Microtus californicus and Possible Emergence of an Exotic Ixodes Species Tick in California.

PubMed

Poulsen, Amanda; Conroy, Chris; Foley, Patrick; Ott-Conn, Caitlin; Roy, Austin; Brown, Richard; Foley, Janet

2015-09-01

California voles (Microtus californicus Peale) harbor fleas and ticks, may be infected with vector-borne pathogens, and could themselves suffer from disease and serve as a source of infection for people and other animals. Here we summarize publications, museum archives, and recent records of ticks and fleas from California voles. There have been 18 flea species reported on California voles with geographic locations reported for 13. During recent statewide surveys, we found six flea species, with the highest species richness in Humboldt County. We found three of five previously reported tick species as well as a tick resembling the eastern North American tick Ixodes minor Neumann (which we here designate Ixodes "Mojave morphotype") on isolated Amargosa voles and Owens Valley voles (Microtus californicus vallicola Bailey) in Inyo County in 2012 and 2014. Additional incidental observations of this Mojave morphotype tick were on a western harvest mouse (Reithrodontomys megalotis Baird) at the Mojave site and a montane vole (Microtus montanus Peale) in the Owens Valley, both in March, 2014. We cannot rule out that this tick species has been present in remote areas of California but gone unrecognized, but these data are consistent with recent introduction of this tick, possibly from migrating birds. Changes in the ectoparasite fauna suggest changing ecologies of vectors and vector-borne pathogens that could influence animals and people as well. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Investigation of tick vectors of Hepatozoon canis in Brazil.

PubMed

Demoner, Larissa de Castro; Rubini, Adriano Stefani; Paduan, Karina dos Santos; Metzger, Betina; de Paula Antunes, João Marcelo Azevedo; Martins, Thiago Fenandes; Mathias, Maria Izabel Camargo; O'Dwyer, Lucia Helena

2013-12-01

Hepatozoon canis is a common apicomplexan parasite of dogs. In Brazil, in addition to Rhipicephalus sanguineus, Amblyomma ovale, Amblyomma cajennense, and Rhipicephalus (Boophilus) microplus have been suggested to act as vectors. The present study aimed to evaluate, under controlled conditions, the acquisition of H. canis by A. ovale, R. sanguineus, and A. cajennense after feeding on naturally infected dogs. Cytological and histophatological examinations were performed to recover oocysts and other sporogonic stages of the protozoan from the experimentally infected nymphs and adults. None of the R. sanguineus (n=30) or A. cajennense nymphs (n=15) that were dissected after feeding on H. canis naturally infected dogs became infected by the hemoparasite. Likewise, none of the R. sanguineus (n=165) and A. cajennense (n=114) adult ticks that were fed as nymphs on dogs demonstrated infection. Additionally, A. cajennense adult ticks were incapable of acquiring the infection, since no parasite was found in 62 adults that fed on H. canis-infected dogs. With regard to A. ovale ticks, 2 different infestations were carried out. Firstly, a dog with naturally occurring hepatozoonosis was infested with A. ovale adults originating from Rondônia, Brazil. Ticks fed to full engorgement. A total of 31 adults was collected from the dog and dissected on the third day after natural detachment. Oocysts were detected in 13 (42%) of the ticks. The second experimental infestation was carried out using adult ticks originating from São Paulo, Brazil. Surprisingly, of the 103 dissected ticks, only one (1%) contained oocysts in the hemocoel. No other sporogonic stage was found. Results indicate that different strains of A. ovale ticks may exist in Brazil with different susceptibilities to pathogens. Furthermore, it is possible that R. sanguineus and A. cajennense have little or no importance in the transmission of H. canis in rural areas of Brazil. Copyright © 2013 Elsevier GmbH. All rights reserved.

Influence of altitude on tick-borne encephalitis infection risk in the natural foci of the Altai Republic, Southern Siberia.

PubMed

Shchuchinova, L D; Kozlova, I V; Zlobin, V I

2015-04-01

The Altai Republic is a highly endemic area as far as tick-borne encephalitis (TBE) is concerned. The aim of the research was to study the effect of altitude on the risk of tick-borne encephalitis infection in the Altai Republic. The paper analyzes the following data: the study of ixodid ticks collected from the vegetation in 116 sites at the 200-2383m elevation above sea level in 2012-2014, TBE virus prevalence of these vectors, tick-bite incidence rate, and TBE incidence rate of the population. Species identification of 4503 specimens has shown that the most common species are Dermacentor nuttalli (45.3%), Ixodes persulcatus (33.1%), Dermacentor silvarum (9.4%), Dermacentor reticulatus (8.9%), and Haemaphysalis concinna (5.0%). A total of 2997 adult ixodid ticks were studied for the presence of the TBE virus; 2163 samples were examined by ELISA, while 834 specimens were tested by PCR. The TBE virus prevalence of Dermacentor spp. ticks in both reactions was significantly higher than of Ixodes persulcatus ticks (p<0.001). The work shows that the altitude is an important factor in the development of the epidemiological situation of tick-borne encephalitis: the higher the elevation of the area above sea level, the smaller the range of vectors. There is also a change of a leading species: in middle altitude (800-1700m above sea level) the virus is transmitted by ticks of D. nuttalli along with I. persulcatus, and in high mountains (above 1700m above sea level) D. nuttalli becomes an absolute dominant species. However, these species of ticks are less effective vectors than I. persulcatus. With the increase of altitude the tick-bite incidence rate decreases (r=-0.78, p<0.05), and TBE incidence also reduces (r=-0.67, p<0.05). Copyright © 2015 Elsevier GmbH. All rights reserved.

Concurrent micro-RNA mediated silencing of tick-borne flavivirus replication in tick vector and in the brain of vertebrate host.

PubMed

Tsetsarkin, Konstantin A; Liu, Guangping; Kenney, Heather; Hermance, Meghan; Thangamani, Saravanan; Pletnev, Alexander G

2016-09-13

Tick-borne viruses include medically important zoonotic pathogens that can cause life-threatening diseases. Unlike mosquito-borne viruses, whose impact can be restrained via mosquito population control programs, for tick-borne viruses only vaccination remains the reliable means of disease prevention. For live vaccine viruses a concern exists, that spillovers from viremic vaccinees could result in introduction of genetically modified viruses into sustainable tick-vertebrate host transmission cycle in nature. To restrict tick-borne flavivirus (Langat virus, LGTV) vector tropism, we inserted target sequences for tick-specific microRNAs (mir-1, mir-275 and mir-279) individually or in combination into several distant regions of LGTV genome. This caused selective attenuation of viral replication in tick-derived cells. LGTV expressing combinations of target sequences for tick- and vertebrate CNS-specific miRNAs were developed. The resulting viruses replicated efficiently and remained stable in simian Vero cells, which do not express these miRNAs, however were severely restricted to replicate in tick-derived cells. In addition, simultaneous dual miRNA targeting led to silencing of virus replication in live Ixodes ricinus ticks and abolished virus neurotropism in highly permissive newborn mice. The concurrent restriction of adverse replication events in vertebrate and invertebrate hosts will, therefore, ensure the environmental safety of live tick-borne virus vaccine candidates.

Deciphering Babesia-Vector Interactions

PubMed Central

Antunes, Sandra; Rosa, Catarina; Couto, Joana; Ferrolho, Joana; Domingos, Ana

2017-01-01

Understanding host-pathogen-tick interactions remains a vitally important issue that might be better understood by basic research focused on each of the dyad interplays. Pathogens gain access to either the vector or host during tick feeding when ticks are confronted with strong hemostatic, inflammatory and immune responses. A prominent example of this is the Babesia spp.—tick—vertebrate host relationship. Babesia spp. are intraerythrocytic apicomplexan organisms spread worldwide, with a complex life cycle. The presence of transovarial transmission in almost all the Babesia species is the main difference between their life cycle and that of other piroplasmida. With more than 100 species described so far, Babesia are the second most commonly found blood parasite of mammals after trypanosomes. The prevalence of Babesia spp. infection is increasing worldwide and is currently classified as an emerging zoonosis. Babesia microti and Babesia divergens are the most frequent etiological agents associated with human babesiosis in North America and Europe, respectively. Although the Babesia-tick system has been extensively researched, the currently available prophylactic and control methods are not efficient, and chemotherapeutic treatment is limited. Studying the molecular changes induced by the presence of Babesia in the vector will not only elucidate the strategies used by the protozoa to overcome mechanical and immune barriers, but will also contribute toward the discovery of important tick molecules that have a role in vector capacity. This review provides an overview of the identified molecules involved in Babesia-tick interactions, with an emphasis on the fundamentally important ones for pathogen acquisition and transmission. PMID:29034218

Comparative genetic diversity of Lyme disease bacteria in Northern Californian ticks and their vertebrate hosts.

PubMed

Swei, Andrea; Bowie, Verna C; Bowie, Rauri C K

2015-04-01

Vector-borne pathogens are transmitted between vertebrate hosts and arthropod vectors, two immensely different environments for the pathogen. There is further differentiation among vertebrate hosts that often have complex, species-specific immunological responses to the pathogen. All this presents a heterogeneous environmental and immunological landscape with possible consequences on the population genetic structure of the pathogen. We evaluated the differential genetic diversity of the Lyme disease pathogen, Borrelia burgdorferi, in its vector, the western black-legged tick (Ixodes pacificus), and in its mammal host community using the 5S-23S rRNA intergenic spacer region. We found differences in haplotype distribution of B. burgdorferi in tick populations from two counties in California as well as between a sympatric tick and vertebrate host community. In addition, we found that three closely related haplotypes consistently occurred in high frequency in all sample types. Lastly, our study found lower species diversity of the B. burgdorferi species complex, known as B. burgdorferi sensu lato, in small mammal hosts versus the tick populations in a sympatric study area. Copyright © 2015 Elsevier GmbH. All rights reserved.

Amblyomma imitator Ticks as Vectors of Rickettsia rickettsii, Mexico

PubMed Central

Oliveira, Karla A.; Pinter, Adriano; Medina-Sanchez, Aaron; Boppana, Venkata D.; Wikel, Stephen K.; Saito, Tais B.; Shelite, Thomas; Blanton, Lucas; Popov, Vsevolod; Teel, Pete D.; Walker, David H.; Galvao, Marcio A.M.; Mafra, Claudio

2010-01-01

Real-time PCR of Amblyomma imitator tick egg masses obtained in Nuevo Leon State, Mexico, identified a Rickettsia species. Sequence analyses of 17-kD common antigen and outer membrane protein A and B gene fragments showed to it to be R. rickettsii, which suggested a potential new vector for this bacterium. PMID:20678325

Chemical ecology of tick-host interactions

USDA-ARS?s Scientific Manuscript database

Ticks impact the health of livestock and humans world-wide through their roles as pests and vectors of diseases such as heartwater, theileriosis, anaplasmosis, babesiosis, Lyme disease, erhlichiosis, tick-borne encephalitis and Crimean Congo Haemorrhagic fever. Intrinsic to their capacity to serve ...

Tick microbiome: the force within

PubMed Central

Narasimhan, Sukanya; Fikrig, Erol

2015-01-01

Ticks are obligate blood-feeders and serve as vectors of human and livestock pathogens worldwide. Defining the tick microbiome and deciphering the interactions between the tick and its symbiotic bacteria in the context of tick development and pathogen transmission, will likely reveal new insights and spawn new paradigms to control tick-borne diseases. Descriptive observations on the tick microbiome that began almost a century ago serve as forerunners to the gathering momentum to define the tick microbiome in greater detail. This review will focus on the current efforts to address the microbiomes of diverse ticks, and the evolving understanding of tick microbiomes. There is hope that these efforts will bring a holistic understanding of pathogen transmission by ticks. PMID:25936226

Correlation of TBE Incidence with Red Deer and Roe Deer Abundance in Slovenia

PubMed Central

Knap, Nataša; Avšič-Županc, Tatjana

2013-01-01

Tick-borne encephalitis (TBE) is a virus infection which sometimes causes human disease. The TBE virus is found in ticks and certain vertebrate tick hosts in restricted endemic localities termed TBE foci. The formation of natural foci is a combination of several factors: the vectors, a suitable and numerous enough number of hosts and in a habitat with suitable vegetation and climate. The present study investigated the influence of deer on the incidence of tick-borne encephalitis. We were able to obtain data from deer culls. Using this data, the abundance of deer was estimated and temporal and spatial analysis was performed. The abundance of deer has increased in the past decades, as well as the incidence of tick-borne encephalitis. Temporal analysis confirmed a correlation between red deer abundance and tick-borne encephalitis occurrence. Additionally, spatial analysis established, that in areas with high incidence of tick-borne encephalitis red deer density is higher, compared to areas with no or few human cases of tick-borne encephalitis. However, such correlation could not be confirmed between roe deer density and the incidence of tick-borne encephalitis. This is presumably due to roe deer density being above a certain threshold so that availability of tick reproduction hosts has no apparent effect on ticks' host finding and consequently may not be possible to correlate with incidence of human TBE. PMID:23776668

Exploring the use of anti-tick vaccine as tool for integrated eradication of the cattle fever tick, Rhipicephalus (Boophilus) annulatus

USDA-ARS?s Scientific Manuscript database

Bovine babesiosis, also known as cattle fever, is a tick-borne protozoal disease foreign to the United States. It was eradicated by eliminating the vector species, Rhipicephalus (Boophilus) annulatus and R. (B.) microplus, through the efforts of the Cattle Fever Tick Eradication Program (CFTEP), wit...

Repellency and toxicity of five ant defensive compounds against the lone star tick, Amblyomma americanum (Acari: Ixodidae)

USDA-ARS?s Scientific Manuscript database

+ The lone star tick, Amblyomma americanum, is a vector of several important human and animal diseases. This tick species has rapidly expanded in its geographic distribution, and its aggressive behavior has increased the risk of tick-borne diseases in these new areas. Repellents are recommended by t...

Dermacentor andersoni transmission of Francisella tularensis subsp. novicida reflects bacterial colonization, dissemination and replication coordinated with tick feeding.

USDA-ARS?s Scientific Manuscript database

Ticks serve as biological vectors for a wide variety of bacterial pathogens which must be able to efficiently colonize specific tick tissues prior to transmission. The bacterial determinants of tick colonization are largely unknown, a knowledge gap attributed in large part to the paucity of tools t...

Research on the ecology of ticks and tick-borne pathogens—methodological principles and caveats

PubMed Central

Estrada-Peña, Agustín; Gray, Jeremy S.; Kahl, Olaf; Lane, Robert S.; Nijhof, Ard M.

2013-01-01

Interest in tick-transmitted pathogens has experienced an upsurge in the past few decades. Routine application of tools for the detection of fragments of foreign DNA in ticks, together with a high degree of interest in the quantification of disease risk for humans, has led to a marked increase in the number of reports on the eco-epidemiology of tick-borne diseases. However, procedural errors continue to accumulate in the scientific literature, resulting in misleading information. For example, unreliable identification of ticks and pathogens, erroneous interpretations of short-term field studies, and the hasty acceptance of some tick species as vectors have led to ambiguities regarding the vector role of these arthropods. In this review, we focus on the ecological features driving the life cycle of ticks and the resulting effects on the eco-epidemiology of tick-transmitted pathogens. We review the factors affecting field collections of ticks, and we describe the biologically and ecologically appropriate procedures for describing tick host-seeking activity and its correlation with environmental traits. We detail the climatic variables that have biological importance on ticks and explain how they should be properly measured and analyzed. We also provide evidence to critically reject the use of some environmental traits that are being increasingly reported as the drivers of the behavior of ticks. With the aim of standardization, we propose unambiguous definitions of the status of hosts and ticks regarding their ability to maintain and spread a given pathogen. We also describe laboratory procedures and standards for evaluating the vectorial capacity of a tick or the reservoir role of a host. This approach should provide a coherent framework for the reporting of research findings concerning ticks and tick-borne diseases. PMID:23964348

Research on the ecology of ticks and tick-borne pathogens--methodological principles and caveats.

PubMed

Estrada-Peña, Agustín; Gray, Jeremy S; Kahl, Olaf; Lane, Robert S; Nijhof, Ard M

2013-01-01

Interest in tick-transmitted pathogens has experienced an upsurge in the past few decades. Routine application of tools for the detection of fragments of foreign DNA in ticks, together with a high degree of interest in the quantification of disease risk for humans, has led to a marked increase in the number of reports on the eco-epidemiology of tick-borne diseases. However, procedural errors continue to accumulate in the scientific literature, resulting in misleading information. For example, unreliable identification of ticks and pathogens, erroneous interpretations of short-term field studies, and the hasty acceptance of some tick species as vectors have led to ambiguities regarding the vector role of these arthropods. In this review, we focus on the ecological features driving the life cycle of ticks and the resulting effects on the eco-epidemiology of tick-transmitted pathogens. We review the factors affecting field collections of ticks, and we describe the biologically and ecologically appropriate procedures for describing tick host-seeking activity and its correlation with environmental traits. We detail the climatic variables that have biological importance on ticks and explain how they should be properly measured and analyzed. We also provide evidence to critically reject the use of some environmental traits that are being increasingly reported as the drivers of the behavior of ticks. With the aim of standardization, we propose unambiguous definitions of the status of hosts and ticks regarding their ability to maintain and spread a given pathogen. We also describe laboratory procedures and standards for evaluating the vectorial capacity of a tick or the reservoir role of a host. This approach should provide a coherent framework for the reporting of research findings concerning ticks and tick-borne diseases.

Interaction of the Lyme disease spirochete with its tick vector.

PubMed

Caimano, Melissa J; Drecktrah, Dan; Kung, Faith; Samuels, D Scott

2016-07-01

Borrelia burgdorferi, the causative agent of Lyme disease (along with closely related genospecies), is in the deeply branching spirochete phylum. The bacterium is maintained in nature in an enzootic cycle that involves transmission from a tick vector to a vertebrate host and acquisition from a vertebrate host to a tick vector. During its arthropod sojourn, B. burgdorferi faces a variety of stresses, including nutrient deprivation. Here, we review some of the spirochetal factors that promote persistence, maintenance and dissemination of B. burgdorferi in the tick, and then focus on the utilization of available carbohydrates as well as the exquisite regulatory systems invoked to adapt to the austere environment between blood meals and to signal species transitions as the bacteria traverse their enzootic cycle. The spirochetes shift their source of carbon and energy from glucose in the vertebrate to glycerol in the tick. Regulation of survival under limiting nutrients requires the classic stringent response in which RelBbu controls the levels of the alarmones guanosine tetraphosphate and guanosine pentaphosphate (collectively termed (p)ppGpp), while regulation at the tick-vertebrate interface as well as regulation of protective responses to the blood meal require the two-component system Hk1/Rrp1 to activate production of the second messenger cyclic-dimeric-GMP (c-di-GMP). © 2016 John Wiley & Sons Ltd.

Citizen Science and Community Engagement in Tick Surveillance-A Canadian Case Study.

PubMed

Lewis, Julie; Boudreau, Corinne R; Patterson, James W; Bradet-Legris, Jonathan; Lloyd, Vett K

2018-03-02

Lyme disease is the most common tick-borne disease in North America and Europe, and on-going surveillance is required to monitor the spread of the tick vectors as their populations expand under the influence of climate change. Active surveillance involves teams of researchers collecting ticks from field locations with the potential to be sites of establishing tick populations. This process is labor- and time-intensive, limiting the number of sites monitored and the frequency of monitoring. Citizen science initiatives are ideally suited to address this logistical problem and generate high-density and complex data from sites of community importance. In 2014, the same region was monitored by academic researchers, public health workers, and citizen scientists, allowing a comparison of the strengths and weaknesses of each type of surveillance effort. Four community members persisted with tick collections over several years, collectively recovering several hundred ticks. Although deviations from standard surveillance protocols and the choice of tick surveillance sites makes the incorporation of community-generated data into conventional surveillance analyses more complex, this citizen science data remains useful in providing high-density longitudinal tick surveillance of a small area in which detailed ecological observations can be made. Most importantly, partnership between community members and researchers has proven a powerful tool in educating communities about of the risk of tick-vectored diseases and in encouraging tick bite prevention.

Association of Borrelia and Rickettsia spp. and bacterial loads in Ixodes ricinus ticks.

PubMed

Raulf, Marie-Kristin; Jordan, Daniela; Fingerle, Volker; Strube, Christina

2018-01-01

In recent years, awareness of coinfections has increased as synergistic or antagonistic effects on interacting bacteria have been observed. To date, several reports on coinfections of ticks with Rickettsia and Borrelia spp. are available. However, associations are rarely described and studies are based on rather low sample sizes. In the present study, coinfections of Ixodes ricinus with these pathogens were investigated by determining their association in a meta-analysis. A total of 5079 tick samples examined for Rickettsia and Borrelia spp. via probe-based quantitative real-time PCR in previous prevalence studies or as submitted diagnostic material were included. In Borrelia-positive ticks, genospecies were determined by Reverse Line Blot. Determination of bacterial loads resulted in an increase between developmental tick stages with highest mean bacterial loads in female ticks (7.96×10 4 in Borrelia single-infected, 4.87×10 5 in Rickettsia single-infected and 3.22×10 5 in Borrelia-Rickettsia coinfected females). The determined Borrelia-Rickettsia tick coinfection rate was 12.3% (626/5079) with a significant difference to the expected coinfection rate of 9.0% (457/5079). A significant slight association as well as correlation between Borrelia and Rickettsia were determined. In addition, a significant interrelation of the bacterial load in coinfected ticks was shown. At the level of Borrelia genospecies, significant weak associations with Rickettsia spp. were detected for B. afzelii, B. garinii/bavariensis, B. valaisiana and B. lusitaniae. The positive association provides evidence for interactions between Borrelia and Rickettsia spp. in the tick vector, presumably resulting in higher bacterial replication rates in the tick vector and possibly the reservoir host. However, coinfection may impact the vector negatively as indicated by an absent increase in coinfection rates from nymphs to adults. Future studies are needed to investigate the underlying mechanisms of the positive association in ticks and possible associations in the vertebrate host as well as the potential influence of environmental factors. Copyright © 2017 Elsevier GmbH. All rights reserved.

Molecular Detection and Characterization of Tick-borne Pathogens in Dogs and Ticks from Nigeria

PubMed Central

Kamani, Joshua; Baneth, Gad; Mumcuoglu, Kosta Y.; Waziri, Ndadilnasiya E.; Eyal, Osnat; Guthmann, Yifat; Harrus, Shimon

2013-01-01

Background Only limited information is currently available on the prevalence of vector borne and zoonotic pathogens in dogs and ticks in Nigeria. The aim of this study was to use molecular techniques to detect and characterize vector borne pathogens in dogs and ticks from Nigeria. Methodology/Principal Findings Blood samples and ticks (Rhipicephalus sanguineus, Rhipicephalus turanicus and Heamaphysalis leachi) collected from 181 dogs from Nigeria were molecularly screened for human and animal vector-borne pathogens by PCR and sequencing. DNA of Hepatozoon canis (41.4%), Ehrlichia canis (12.7%), Rickettsia spp. (8.8%), Babesia rossi (6.6%), Anaplasma platys (6.6%), Babesia vogeli (0.6%) and Theileria sp. (0.6%) was detected in the blood samples. DNA of E. canis (23.7%), H. canis (21.1%), Rickettsia spp. (10.5%), Candidatus Neoehrlichia mikurensis (5.3%) and A. platys (1.9%) was detected in 258 ticks collected from 42 of the 181 dogs. Co- infections with two pathogens were present in 37% of the dogs examined and one dog was co-infected with 3 pathogens. DNA of Rickettsia conorii israelensis was detected in one dog and Rhipicephalus sanguineus tick. DNA of another human pathogen, Candidatus N. mikurensis was detected in Rhipicephalus sanguineus and Heamaphysalis leachi ticks, and is the first description of Candidatus N. mikurensis in Africa. The Theileria sp. DNA detected in a local dog in this study had 98% sequence identity to Theileria ovis from sheep. Conclusions/Significance The results of this study indicate that human and animal pathogens are abundant in dogs and their ticks in Nigeria and portray the potential high risk of human exposure to infection with these agents. PMID:23505591

Cascading effect of economic globalization on human risks of scrub typhus and tick-borne rickettsial diseases.

PubMed

Kuo, Chi-Chien; Huang, Jing-Lun; Shu, Pei-Yun; Lee, Pei-Lung; Kelt, Douglas A; Wang, Hsi-Chieh

2012-09-01

The increase in global travel and trade has facilitated the dissemination of disease vectors. Globalization can also indirectly affect vector-borne diseases through the liberalization of cross-border trade, which has far-reaching, worldwide effects on agricultural practices and may in turn influence vectors through the modification of the ecological landscape. While the cascading effect of economic globalization on vector-borne diseases, sometimes acting synergistically with regional agricultural policy, could be substantial and have significant economic, agricultural, and public health implications, research into this remains very limited. We evaluated how abandonment of rice paddies in Taiwan after joining the World Trade Organization, along with periodic plowing, an agricultural policy to reduce farm pests in abandoned fields can unexpectedly influence risks to diseases transmitted by ticks and chiggers (larval trombiculid mites), which we collected from their small-mammal hosts. Sampling was limited to abandoned (fallow) and plowed fields due to the challenge of trapping small mammals in flooded rice paddies. Striped field mice (Apodemus agrarius) are the main hosts for both vectors. They harbored six times more ticks and three times more chiggers in fallow than in plowed plots. The proportion of ticks infected with Rickettsia spp. (etiologic agent of spotted fever) was three times higher in fallow plots, while that of Orientia tsutsugamushi (scrub typhus) in chiggers was similar in both treatments. Fallow plots had more ground cover and higher vegetation than plowed ones. Moreover, ticks and chiggers in both field types were dominated by species known to infest humans. Because ticks and chiggers should exhibit very low survival in flooded rice paddies, we propose that farm abandonment in Taiwan, driven by globalization, may have inadvertently led to increased risks of spotted fever and scrub typhus. However, periodic plowing can unintentionally mitigate vector burdens. Economic globalization can have unexpected consequences on disease risk through modification of the agricultural landscape, but the outcome may also be influenced by agricultural policies, calling for further research on vector-borne diseases and their control from broader perspectives.

Tick-Borne Viruses and Biological Processes at the Tick-Host-Virus Interface

PubMed Central

Kazimírová, Mária; Thangamani, Saravanan; Bartíková, Pavlína; Hermance, Meghan; Holíková, Viera; Štibrániová, Iveta; Nuttall, Patricia A.

2017-01-01

Ticks are efficient vectors of arboviruses, although less than 10% of tick species are known to be virus vectors. Most tick-borne viruses (TBV) are RNA viruses some of which cause serious diseases in humans and animals world-wide. Several TBV impacting human or domesticated animal health have been found to emerge or re-emerge recently. In order to survive in nature, TBV must infect and replicate in both vertebrate and tick cells, representing very different physiological environments. Information on molecular mechanisms that allow TBV to switch between infecting and replicating in tick and vertebrate cells is scarce. In general, ticks succeed in completing their blood meal thanks to a plethora of biologically active molecules in their saliva that counteract and modulate different arms of the host defense responses (haemostasis, inflammation, innate and acquired immunity, and wound healing). The transmission of TBV occurs primarily during tick feeding and is a complex process, known to be promoted by tick saliva constituents. However, the underlying molecular mechanisms of TBV transmission are poorly understood. Immunomodulatory properties of tick saliva helping overcome the first line of defense to injury and early interactions at the tick-host skin interface appear to be essential in successful TBV transmission and infection of susceptible vertebrate hosts. The local host skin site of tick attachment, modulated by tick saliva, is an important focus of virus replication. Immunomodulation of the tick attachment site also promotes co-feeding transmission of viruses from infected to non-infected ticks in the absence of host viraemia (non-viraemic transmission). Future research should be aimed at identification of the key tick salivary molecules promoting virus transmission, and a molecular description of tick-host-virus interactions and of tick-mediated skin immunomodulation. Such insights will enable the rationale design of anti-tick vaccines that protect against disease caused by tick-borne viruses. PMID:28798904

Tick-Borne Viruses and Biological Processes at the Tick-Host-Virus Interface.

PubMed

Kazimírová, Mária; Thangamani, Saravanan; Bartíková, Pavlína; Hermance, Meghan; Holíková, Viera; Štibrániová, Iveta; Nuttall, Patricia A

2017-01-01

Ticks are efficient vectors of arboviruses, although less than 10% of tick species are known to be virus vectors. Most tick-borne viruses (TBV) are RNA viruses some of which cause serious diseases in humans and animals world-wide. Several TBV impacting human or domesticated animal health have been found to emerge or re-emerge recently. In order to survive in nature, TBV must infect and replicate in both vertebrate and tick cells, representing very different physiological environments. Information on molecular mechanisms that allow TBV to switch between infecting and replicating in tick and vertebrate cells is scarce. In general, ticks succeed in completing their blood meal thanks to a plethora of biologically active molecules in their saliva that counteract and modulate different arms of the host defense responses (haemostasis, inflammation, innate and acquired immunity, and wound healing). The transmission of TBV occurs primarily during tick feeding and is a complex process, known to be promoted by tick saliva constituents. However, the underlying molecular mechanisms of TBV transmission are poorly understood. Immunomodulatory properties of tick saliva helping overcome the first line of defense to injury and early interactions at the tick-host skin interface appear to be essential in successful TBV transmission and infection of susceptible vertebrate hosts. The local host skin site of tick attachment, modulated by tick saliva, is an important focus of virus replication. Immunomodulation of the tick attachment site also promotes co-feeding transmission of viruses from infected to non-infected ticks in the absence of host viraemia (non-viraemic transmission). Future research should be aimed at identification of the key tick salivary molecules promoting virus transmission, and a molecular description of tick-host-virus interactions and of tick-mediated skin immunomodulation. Such insights will enable the rationale design of anti-tick vaccines that protect against disease caused by tick-borne viruses.

Efficient method for extracting DNA of parasites causing bovine babesiosis from tick vectors

USDA-ARS?s Scientific Manuscript database

The southern cattle tick, Rhipicephalus (Boophilus) microplus, is an economically important pest costing animal agriculture billions of dollars worldwide. This research focuses on a comparison of three different tick DNA extraction methods: phenol-chloroform extraction (method 1), a modified version...

Modern advances in sustainable tick control

USDA-ARS?s Scientific Manuscript database

Ticks are the vector of the many different organisms responsible for both animal and human diseases. Understanding the progress we have made and new directions in tick control is critical to the sustainability of human and animal health. The integration of vaccines, acaricides, and new acaricide ap...

Molecular Evidence of Bartonella Species in Ixodid Ticks and Domestic Animals in Palestine.

PubMed

Ereqat, Suheir; Nasereddin, Abdelmajeed; Vayssier-Taussat, Muriel; Abdelkader, Ahmad; Al-Jawabreh, Amer; Zaid, Taher; Azmi, Kifaya; Abdeen, Ziad

2016-01-01

Ticks play an important role in disease transmission as vectors for human and animal pathogens, including the Gram-negative pathogen Bartonella. Here, we evaluated the presence of Bartonella in ixodid ticks and domestic animals from Palestine. We tested 633 partly engorged ticks and 139 blood samples from domestic animals (dogs, sheep and camels) for Bartonella using ITS-PCR. Bartonella DNA was detected in 3.9% of the tested ticks. None of the ticks collected from sheep and goats were positive for Bartonella. Seventeen R. sanguineus ticks (17/391; 4.3%) collected from dogs were infected with B. rochalimae (n = 10), B. chomelii (n = 6), and B. koehlerae (n = 1). Four H. dromedarri ticks (4/63; 6.3%) obtained from camels were infected with B. bovis (n = 2) and B. rochalimae (n = 2). Among canine blood samples (n = 110), we found one asymptomatic female dog to be infected with B. rochalimae (0.9%). The detection of zoonotic Bartonella species in this study should raise awareness of these vector-borne diseases among physicians, veterinarians and public health workers and highlight the importance of surveillance and preventive measures in the region.

Comparison of Vector Efficiency of Ixodes scapularis (Acari: Ixodidae) From the Northeast and Upper Midwest of the United States for the Lyme Disease Spirochete Borrelia mayonii.

PubMed

Eisen, Lars; Breuner, Nicole E; Hojgaard, Andrias; Hoxmeier, J Charles; Pilgard, Mark A; Replogle, Adam J; Biggerstaff, Brad J; Dolan, Marc C

2017-01-01

Borrelia mayonii, a recently recognized species within the Borrelia burgdorferi sensu lato complex, has been detected in host-seeking Ixodes scapularis Say ticks and found to be associated with Lyme disease in the Upper Midwest. This spirochete has, to date, not been documented from the Northeast, but we previously demonstrated that I. scapularis ticks originating from Connecticut are capable of serving as a vector of B. mayonii In this follow-up study, we compared the vector efficiency for B. mayonii (strain MN14-1420) of I. scapularis ticks originating from Minnesota in the Upper Midwest and Connecticut in the Northeast. CD-1 outbred white mice previously infected with B. mayonii via tick bite were exposed to simultaneous feeding by Minnesota and Connecticut larvae contained within separate feeding capsules. We found no difference in the ability of Minnesota and Connecticut larvae to acquire B. mayonii from infected mice and pass spirochetes to the nymphal stage (overall nymphal infection rates of 11.6 and 13.3%, respectively). Moreover, the efficiency of transmission of B. mayonii by single infected nymphs was similar for the Minnesota and Connecticut ticks (33 and 44%, respectively). We conclude that the examined I. scapularis ticks from the Upper Midwest and Northeast did not differ in their efficiency as vectors for B. mayonii. Published by Oxford University Press on behalf of Entomological Society of America 2016 This work is written by US Government employees and is in the public domain in the US.

[The pigeon tick, Argas reflexus, and hazard for human health].

PubMed

Khoury, Cristina; Maroli, Michele

2004-01-01

The massive presence of the pigeon (Columba livia f. domestica) in urban areas not only is cause of serious aesthetic damages as decline of squares, of churches, of statues and buildings, but often creates many hygienic and medical problems. The pigeon, in fact, can transmit a great number of pathogenic agents and also be infested by several ectoparasites. Among these, Argas reflexus (Acari: Argasidae), the well known pigeon tick, is the most important ectoparasite that can involve also human health. Buildings infested by A. reflexus and attacks by this tick species to man are frequently reported, with an increasing interest for human health. In fact the pigeon tick bites can induce anaphylactic reactions for the presence of allergens, and as vector, the tick can also transmit some pathogens. This review deals with actual knowledge on the distribution, eco-biology, vector competence, prevention and control of A. reflexus in Italy.

Rickettsia parkeri Rickettsiosis in Different Ecological Regions of Argentina and Its Association with Amblyomma tigrinum as a Potential Vector

PubMed Central

Romer, Yamila; Nava, Santiago; Govedic, Francisco; Cicuttin, Gabriel; Denison, Amy M.; Singleton, Joseph; Kelly, Aubree J.; Kato, Cecilia Y.; Paddock, Christopher D.

2014-01-01

Rickettsia parkeri, a newly recognized tick-borne pathogen of humans in the Americas, is a confirmed cause of spotted fever group rickettsiosis in Argentina. Until recently, almost all cases of R. parkeri rickettsiosis in Argentina have originated from the Paraná River Delta, where entomological surveys have identified populations of R. parkeri-infected Amblyomma triste ticks. In this report, we describe confirmed cases of R. parkeri rickettsiosis from Córdoba and La Rioja provinces, which are located several hundred kilometers inland, and in a more arid ecological region, where A. triste ticks do not occur. Additionally, we identified questing A. tigrinum ticks naturally infected with R. parkeri in Córdoba province. These data provide evidence that another human-biting tick species serves as a potential vector of R. parkeri in Argentina and possibly, other countries of South America. PMID:25349376

Effects of Climate and Climate Change on Vectors and Vector-Borne Diseases: Ticks Are Different.

PubMed

Ogden, Nick H; Lindsay, L Robbin

2016-08-01

There has been considerable debate as to whether global risk from vector-borne diseases will be impacted by climate change. This has focussed on important mosquito-borne diseases that are transmitted by the vectors from infected to uninfected humans. However, this debate has mostly ignored the biological diversity of vectors and vector-borne diseases. Here, we review how climate and climate change may impact those most divergent of arthropod disease vector groups: multivoltine insects and hard-bodied (ixodid) ticks. We contrast features of the life cycles and behaviour of these arthropods, and how weather, climate, and climate change may have very different impacts on the spatiotemporal occurrence and abundance of vectors, and the pathogens they transmit. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Molecular and MALDI-TOF identification of ticks and tick-associated bacteria in Mali

PubMed Central

Diarra, Adama Zan; Almeras, Lionel; Berenger, Jean-Michel; Koné, Abdoulaye K.; Bocoum, Zakaria; Dabo, Abdoulaye; Doumbo, Ogobara; Raoult, Didier; Parola, Philippe

2017-01-01

Ticks are considered the second vector of human and animal diseases after mosquitoes. Therefore, identification of ticks and associated pathogens is an important step in the management of these vectors. In recent years, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising method for the identification of arthropods including ticks. The objective of this study was to improve the conditions for the preparation of tick samples for their identification by MALDI-TOF MS from field-collected ethanol-stored Malian samples and to evaluate the capacity of this technology to distinguish infected and uninfected ticks. A total of 1,333 ticks were collected from mammals in three distinct sites from Mali. Morphological identification allowed classification of ticks into 6 species including Amblyomma variegatum, Hyalomma truncatum, Hyalomma marginatum rufipes, Rhipicephalus (Boophilus) microplus, Rhipicephalus evertsi evertsi and Rhipicephalus sanguineus sl. Among those, 471 ticks were randomly selected for molecular and proteomic analyses. Tick legs submitted to MALDI-TOF MS revealed a concordant morpho/molecular identification of 99.6%. The inclusion in our MALDI-TOF MS arthropod database of MS reference spectra from ethanol-preserved tick leg specimens was required to obtain reliable identification. When tested by molecular tools, 76.6%, 37.6%, 20.8% and 1.1% of the specimens tested were positive for Rickettsia spp., Coxiella burnetii, Anaplasmataceae and Borrelia spp., respectively. These results support the fact that MALDI-TOF is a reliable tool for the identification of ticks conserved in alcohol and enhances knowledge about the diversity of tick species and pathogens transmitted by ticks circulating in Mali. PMID:28742123

Molecular and MALDI-TOF identification of ticks and tick-associated bacteria in Mali.

PubMed

Diarra, Adama Zan; Almeras, Lionel; Laroche, Maureen; Berenger, Jean-Michel; Koné, Abdoulaye K; Bocoum, Zakaria; Dabo, Abdoulaye; Doumbo, Ogobara; Raoult, Didier; Parola, Philippe

2017-07-01

Ticks are considered the second vector of human and animal diseases after mosquitoes. Therefore, identification of ticks and associated pathogens is an important step in the management of these vectors. In recent years, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising method for the identification of arthropods including ticks. The objective of this study was to improve the conditions for the preparation of tick samples for their identification by MALDI-TOF MS from field-collected ethanol-stored Malian samples and to evaluate the capacity of this technology to distinguish infected and uninfected ticks. A total of 1,333 ticks were collected from mammals in three distinct sites from Mali. Morphological identification allowed classification of ticks into 6 species including Amblyomma variegatum, Hyalomma truncatum, Hyalomma marginatum rufipes, Rhipicephalus (Boophilus) microplus, Rhipicephalus evertsi evertsi and Rhipicephalus sanguineus sl. Among those, 471 ticks were randomly selected for molecular and proteomic analyses. Tick legs submitted to MALDI-TOF MS revealed a concordant morpho/molecular identification of 99.6%. The inclusion in our MALDI-TOF MS arthropod database of MS reference spectra from ethanol-preserved tick leg specimens was required to obtain reliable identification. When tested by molecular tools, 76.6%, 37.6%, 20.8% and 1.1% of the specimens tested were positive for Rickettsia spp., Coxiella burnetii, Anaplasmataceae and Borrelia spp., respectively. These results support the fact that MALDI-TOF is a reliable tool for the identification of ticks conserved in alcohol and enhances knowledge about the diversity of tick species and pathogens transmitted by ticks circulating in Mali.

Scalp eschar and neck lymphadenopathy after tick bite: an emerging syndrome with multiple causes.

PubMed

Dubourg, G; Socolovschi, C; Del Giudice, P; Fournier, P E; Raoult, D

2014-08-01

The clinical and epidemiological features of 56 patients with scalp eschar associated with neck lymphadenopathy after a tick bite (SENLAT) syndrome were evaluated at the National French Rickettsial Center. Eschar swabs, crusts, and biopsies as well as ticks and blood samples were acquired for molecular and serological assays. SENLAT predominantly affects children (p < 0.05), followed by 40- to 70-year-olds, and it is found mostly in women (p < 0.05). The seasonal distribution has two peaks: one in the spring (55%) and one in the autumn (30%). The etiological agent was identified in 18 cases, which include Rickettsia slovaca in 13 cases with incidences of two co-infections with Rickettsia raoultii and one case caused by Rickettsia sibirica mongolitimonae. Other possible agents that were found in attached ticks were Candidatus R. rioja, Coxiella burnetii, and Borrelia burgdorferi. The tick vector was Dermacentor marginatus in almost all cases, with the exception of one case, in which Ixodes ricinus was identified as the vector. Our findings show that SENLAT is a clinical entity characterized as a local infection controlled by the immune system and is neither pathogen- nor vector-specific.

Ticks (Acari: Ixodidae) associated with wildlife and vegetation of Haller park along the Kenyan coastline.

PubMed

Wanzala, W; Okanga, S

2006-09-01

This artcile describes the results obtained from a tick survey conducted in Haller park along the Kenyan coastline. The survey aimed at evaluating tick-host associations, assessing tick population density, and providing baseline information for planning future tick control and management in the park. Ticks (2,968) were collected by handpicking from eight species of wildlife and by dragging in 14 selected sites within the park. A considerable proportion of ticks were also collected from leaves, stems, and bark of most dominant trees, namely, Casuarina equisetifolia L. (Forst. and Forst.), Cocos nucifera L., Adansonia digitata L., Musa paradisiaca L., and Azadiracta indica Adr. Juss. Dragging was conducted in sites predominantly occupied by Cynodon dactylon L. (Pers.), Cenchrus ciliaris L., Stenotaphrum dimidiatum L. (Kuntze.) Brongn., and Brachiaria xantholeuca Hack. Ex Schinz Stapf. and Loudetia kagerensis K. Schum. Hutch. Eight tick species were identified, and the collection included Rhipicephalus pravus Dönitz 1910, Rhipicephalus pulchellus Gerstäcker 1873, Hyalomma marginatum rufipes Koch 1844, Amblyomma gemma Dönitz 1910, Amblyomma hebraeum Koch 1844, Amblyomma sparsum Neumann 1899, Amblyomma nuttalli Dönitz 1909, and Boophilus decoloratus Koch 1844. Given that the identified tick species are known to parasitize humans as well as livestock, there exist risks of emergence of zoonotic infections mediated by tick vectors. In the recreational environment of Haller park, where tick vectors share habitats with hosts, there is a need to develop sustainable and effective tick control and management strategies to minimize economic losses that tick infestation may cause.

Partial pathogen protection by tick-bite sensitization and epitope recognition in peptide-immunized HLA DR3 transgenic mice.

PubMed

Shattuck, Wendy M C; Dyer, Megan C; Desrosiers, Joe; Fast, Loren D; Terry, Frances E; Martin, William D; Moise, Leonard; De Groot, Anne S; Mather, Thomas N

2014-01-01

Ticks are notorious vectors of disease for humans, and many species of ticks transmit multiple pathogens, sometimes in the same tick bite. Accordingly, a broad-spectrum vaccine that targets vector ticks and pathogen transmission at the tick/host interface, rather than multiple vaccines against every possible tickborne pathogen, could become an important tool for resolving an emerging public health crisis. The concept for such a tick protective vaccine comes from observations of an acquired tick resistance (ATR) that can develop in non-natural hosts of ticks following sensitization to tick salivary components. Mice are commonly used as models to study immune responses to human pathogens but normal mice are natural hosts for many species of ticks and fail to develop ATR. We evaluated HLA DR3 transgenic (tg) "humanized" mice as a potential model of ATR and assessed the possibility of using this animal model for tick protective vaccine discovery studies. Serial tick infestations with pathogen-free Ixodes scapularis ticks were used to tick-bite sensitize HLA DR3 tg mice. Sensitization resulted in a cytokine skew favoring a Th2 bias as well as partial (57%) protection to infection with Lyme disease spirochetes (Borrelia burgdorferi) following infected tick challenge when compared to tick naïve counterparts. I. scapularis salivary gland homogenate (SGH) and a group of immunoinformatic-predicted T cell epitopes identified from the I. scapularis salivary transcriptome were used separately to vaccinate HLA DR3 tg mice, and these mice also were assessed for both pathogen protection and epitope recognition. Reduced pathogen transmission along with a Th2 skew resulted from SGH vaccination, while no significant protection and a possible T regulatory bias was seen in epitope-vaccinated mice. This study provides the first proof-of-concept for using HLA DR tg "humanized" mice for studying the potential tick protective effects of immunoinformatic- or otherwise-derived tick salivary components as tickborne disease vaccines.

Lyme disease spirochaete Borrelia burgdorferi does not require thiamin.

PubMed

Zhang, Kai; Bian, Jiang; Deng, Yijie; Smith, Alexis; Nunez, Roy E; Li, Michael B; Pal, Utpal; Yu, Ai-Ming; Qiu, Weigang; Ealick, Steven E; Li, Chunhao

2016-11-21

Thiamin pyrophosphate (ThDP), the active form of thiamin (vitamin B 1 ), is believed to be an essential cofactor for all living organisms 1,2 . Here, we report the unprecedented result that thiamin is dispensable for the growth of the Lyme disease pathogen Borrelia burgdorferi (Bb) 3 . Bb lacks genes for thiamin biosynthesis and transport as well as known ThDP-dependent enzymes 4 , and we were unable to detect thiamin or its derivatives in Bb cells. We showed that eliminating thiamin in vitro and in vivo using BcmE, an enzyme that degrades thiamin, has no impact on Bb growth and survival during its enzootic infectious cycle. Finally, high-performance liquid chromatography analysis reveals that the level of thiamin and its derivatives in Ixodes scapularis ticks, the enzootic vector of Bb, is extremely low. These results suggest that by dispensing with use of thiamin, Borrelia, and perhaps other tick-transmitted bacterial pathogens, are uniquely adapted to survive in tick vectors before transmitting to mammalian hosts. To our knowledge, such a mechanism has not been reported previously in any living organisms.

The characterization and manipulation of the bacterial microbiome of the Rocky Mountain wood tick, Dermacentor andersoni

USDA-ARS?s Scientific Manuscript database

Background: In North America, ticks are the most economically impactful vectors of human and animal pathogens. The Rocky Mountain wood tick, Dermacentor andersoni (Acari: Ixodidae), transmits Rickettsia rickettsii and Anaplasma marginale to humans and cattle, respectively. In recent years, studies h...

Ticks collected from humans, domestic animals, and wildlife in Yucatan, Mexico

USDA-ARS?s Scientific Manuscript database

Domestic animals and wildlife play important roles as reservoirs of zoonotic pathogens that are transmitted to humans by ticks. Besides their role as vectors of several classes of microorganisms of veterinary and public health relevance, ticks also burden human and animal populations through their o...

Reducing tick burdens on chicks by treating breeding female grouse with permethrin

USDA-ARS?s Scientific Manuscript database

Ticks are important arthropod vectors of diseases of human, livestock, and wildlife hosts. In the United Kingdom, the sheep tick (Ixodes ricinus) is increasingly recognized as a main limiting factor of red grouse (Lagopus lagopus) populations, a game bird of high economic value. We evaluated the e...

Identification, characterization and use of two tick promoters for construction of a dual luciferase reporter vector

USDA-ARS?s Scientific Manuscript database

Dual luciferase reporter systems are valuable tools for functional genomic studies, but have not previously been developed for use in tick cell culture. We evaluated expression of available luciferase constructs in tick cell cultures derived from Rhipicephalus (Boophilus) microplus, an important vec...

Effects of Vegetation Microclimate on Larval Cattle Fever Tick Survival

USDA-ARS?s Scientific Manuscript database

Cattle Fever Ticks (CFT), Rhipicephalus annulatus and R. microplus, have been a threat to the livestock industry for many years. These ticks are vectors of cattle fever, a disease produced by the hemoparasite Babesia bovis and B. bigemina. Laboratory research on CFT larval survival has shown that co...

Lyme disease risk in southern California: abiotic and environmental drivers of Ixodes pacificus (Acari: Ixodidae) density and infection prevalence with Borrelia burgdorferi.

PubMed

MacDonald, Andrew J; Hyon, David W; Brewington, John B; O'Connor, Kerry E; Swei, Andrea; Briggs, Cheryl J

2017-01-05

Tick-borne diseases, particularly Lyme disease, are emerging across the northern hemisphere. In order to manage emerging diseases and predict where emergence will likely occur, it is necessary to understand the factors influencing the distribution, abundance and infection prevalence of vector species. In North America, Lyme disease is the most common vector-borne disease and is transmitted by blacklegged ticks. This study aimed to explore the abiotic and environmental drivers of density and infection prevalence of western blacklegged ticks (Ixodes pacificus) in southern California, an understudied and densely populated region of North America. Over the course of this two-year study, densities of I. pacificus adults were consistently positively associated with host availability for juvenile ticks and dense oak woodland habitat. Densities of nymphal and larval I. pacificus, on the other hand were primarily predicted by host availability for juvenile ticks in the first year of the study, and by habitat characteristics such as dense leaf litter in the second year. Infection with the causative agent of Lyme disease, Borrelia burgdorferi (sensu stricto), and related spirochetes was not predicted by the abiotic conditions promoting I. pacificus populations, but rather by diversity of the tick community, and in particular by the presence of two Ixodes tick species that do not generally feed on humans (Ixodes spinipalpis and Ixodes peromysci). Borrelia spp. infection was not detected in the I. pacificus populations sampled, but was detected in other vector species that may maintain enzootic transmission of the pathogen on the landscape. This study identified dense oak woodlands as high-risk habitats for I. pacificus tick encounter in southern California. The shift in relative importance of host availability to habitat characteristics in predicting juvenile tick abundance occurred as California's historic drought intensified, suggesting that habitat providing suitable microclimates for tick survivorship became centrally important to patterns of abundance in the face of deleterious abiotic conditions. These results underscore the need for further investigation of the effects of climate change on tick-borne disease in California. Finally, despite low risk of human Lyme disease infection posed by I. pacificus in southern California, evidence of infection was found in other tick species, suggesting that enzootic transmission of tick-borne borreliae may be occurring in southern California, and involve parallel enzootic cycles with other tick and host species but not necessarily humans.

A retrospective study of the characterization of Rickettsia species in ticks collected from humans.

PubMed

Blanda, Valeria; Torina, Alessandra; La Russa, Francesco; D'Agostino, Rosalia; Randazzo, Kety; Scimeca, Salvatore; Giudice, Elisabetta; Caracappa, Santo; Cascio, Antonio; de la Fuente, José

2017-06-01

Rickettsiae (family Rickettsiaceae, order Rickettsiales) are obligate intracellular bacteria transmitted by arthropod vectors. Several Rickettsia species causing vector-borne rickettsioses belong to the spotted fever group (SFG). Traditionally, Rickettsia conorii has been considered as the main etiologic agent of Mediterranean spotted fever. However, the molecular characterization of rickettsiae allowed identifying other species involved in spotted fever in the Mediterranean region. In this study, 42 ticks collected from humans were subjected to morphological identification and molecular characterization of Rickettsia species potentially involved in human rickettsiosis in Sicily. Fourteen ticks positive to at least two Rickettsia spp. molecular markers were used in the study. Identified Rickettsia spp. included R. conorii, found in Rhipicephalus sanguineus sensu lato and Rhipicephalus turanicus, Rickettsia aeschlimannii found in Hyalomma marginatum, Hyalomma lusitanicum, Dermacentor marginatus and Ixodes ricinus, Rickettsia massiliae found in R. turanicus and R. sanguineus s.l., and Rickettsia slovaca found in D. marginatus and R. sanguineus s.l. Our results showed a great variety of zoonotic Rickettsia spp. in ticks collected from humans in Sicily. The Rickettsia spp. reported in this study were identified in previously recognized or new potential tick vectors in Europe, highlighting the risk of infection by different Rickettsia spp. for humans bitten by ticks in Sicily. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

Invasion of the lyme disease vector Ixodes scapularis: implications for Borrelia burgdorferi endemicity.

PubMed

Hamer, Sarah A; Tsao, Jean I; Walker, Edward D; Hickling, Graham J

2010-08-01

Lyme disease risk is increasing in the United States due in part to the spread of blacklegged ticks Ixodes scapularis, the principal vector of the spirochetal pathogen Borrelia burgdorferi. A 5-year study was undertaken to investigate hypothesized coinvasion of I. scapularis and B. burgdorferi in Lower Michigan. We tracked the spatial and temporal dynamics of the tick and spirochete using mammal, bird, and vegetation drag sampling at eight field sites along coastal and inland transects originating in a zone of recent I. scapularis establishment. We document northward invasion of these ticks along Michigan's west coast during the study period; this pattern was most evident in ticks removed from rodents. B. burgdorferi infection prevalences in I. scapularis sampled from vegetation in the invasion zone were 9.3% and 36.6% in nymphs and adults, respectively, with the majority of infection (95.1%) found at the most endemic site. There was no evidence of I. scapularis invasion along the inland transect; however, low-prevalence B. burgdorferi infection was detected in other tick species and in wildlife at inland sites, and at northern coastal sites in years before the arrival of I. scapularis. These infections suggest that cryptic B. burgdorferi transmission by other vector-competent tick species is occurring in the absence of I. scapularis. Other Borrelia spirochetes, including those that group with B. miyamotoi and B. andersonii, were present at a low prevalence within invading ticks and local wildlife. Reports of Lyme disease have increased significantly in the invasion zone in recent years. This rapid blacklegged tick invasion--measurable within 5 years--in combination with cryptic pathogen maintenance suggests a complex ecology of Lyme disease emergence in which wildlife sentinels can provide an early warning of disease emergence.

[Diseases transmitted by ticks locally and abroad].

PubMed

Gétaz, L; Loutan, L; Mezger, N

2012-05-09

This article provides a brief overview of some diseases transmitted by ticks. These vectors do not transmit only Lyme disease and tickborne-encephalitis, even in Switzerland. Several tick-borne diseases cause nonspecific flu-like symptoms. Nevertheless sometimes severe, some of these diseases can be treated with specific treatments. Repellents, appropriate clothes impregnated with permethrine and prompt removal of the tick are effective preventive measures to limit the risk of infection. There is an effective vaccine which protects against tick-borne encephalitis.

The Tick Microbiome: Why Non-pathogenic Microorganisms Matter in Tick Biology and Pathogen Transmission

PubMed Central

Bonnet, Sarah I.; Binetruy, Florian; Hernández-Jarguín, Angelica M.; Duron, Olivier

2017-01-01

Ticks are among the most important vectors of pathogens affecting humans and other animals worldwide. They do not only carry pathogens however, as a diverse group of commensal and symbiotic microorganisms are also present in ticks. Unlike pathogens, their biology and their effect on ticks remain largely unexplored, and are in fact often neglected. Nonetheless, they can confer multiple detrimental, neutral, or beneficial effects to their tick hosts, and can play various roles in fitness, nutritional adaptation, development, reproduction, defense against environmental stress, and immunity. Non-pathogenic microorganisms may also play a role in driving transmission of tick-borne pathogens (TBP), with many potential implications for both human and animal health. In addition, the genetic proximity of some pathogens to mutualistic symbionts hosted by ticks is evident when studying phylogenies of several bacterial genera. The best examples are found within members of the Rickettsia, Francisella, and Coxiella genera: while in medical and veterinary research these bacteria are traditionally recognized as highly virulent vertebrate pathogens, it is now clear to evolutionary ecologists that many (if not most) Coxiella, Francisella, and Rickettsia bacteria are actually non-pathogenic microorganisms exhibiting alternative lifestyles as mutualistic ticks symbionts. Consequently, ticks represent a compelling yet challenging system in which to study microbiomes and microbial interactions, and to investigate the composition, functional, and ecological implications of bacterial communities. Ultimately, deciphering the relationships between tick microorganisms as well as tick symbiont interactions will garner invaluable information, which may aid in the future development of arthropod pest and vector-borne pathogen transmission control strategies. PMID:28642842

The Tick Microbiome: Why Non-pathogenic Microorganisms Matter in Tick Biology and Pathogen Transmission.

PubMed

Bonnet, Sarah I; Binetruy, Florian; Hernández-Jarguín, Angelica M; Duron, Olivier

2017-01-01

Ticks are among the most important vectors of pathogens affecting humans and other animals worldwide. They do not only carry pathogens however, as a diverse group of commensal and symbiotic microorganisms are also present in ticks. Unlike pathogens, their biology and their effect on ticks remain largely unexplored, and are in fact often neglected. Nonetheless, they can confer multiple detrimental, neutral, or beneficial effects to their tick hosts, and can play various roles in fitness, nutritional adaptation, development, reproduction, defense against environmental stress, and immunity. Non-pathogenic microorganisms may also play a role in driving transmission of tick-borne pathogens (TBP), with many potential implications for both human and animal health. In addition, the genetic proximity of some pathogens to mutualistic symbionts hosted by ticks is evident when studying phylogenies of several bacterial genera. The best examples are found within members of the Rickettsia, Francisella , and Coxiella genera: while in medical and veterinary research these bacteria are traditionally recognized as highly virulent vertebrate pathogens, it is now clear to evolutionary ecologists that many (if not most) Coxiella, Francisella , and Rickettsia bacteria are actually non-pathogenic microorganisms exhibiting alternative lifestyles as mutualistic ticks symbionts. Consequently, ticks represent a compelling yet challenging system in which to study microbiomes and microbial interactions, and to investigate the composition, functional, and ecological implications of bacterial communities. Ultimately, deciphering the relationships between tick microorganisms as well as tick symbiont interactions will garner invaluable information, which may aid in the future development of arthropod pest and vector-borne pathogen transmission control strategies.

Artificial feeding of Rhipicephalus microplus female ticks with anti calreticulin serum do not influence tick and Babesia bigemina acquisition.

PubMed

Antunes, Sandra; Merino, Octávio; Lérias, Joana; Domingues, Nuno; Mosqueda, Juan; de la Fuente, José; Domingos, Ana

2015-02-01

Ticks are obligate haematophagous ectoparasites considered the principal vectors of disease among animals. Rhipicephalus microplus and R. annulatus ticks are the most important vectors for Babesia bigemina and B. bovis, two of the most important intraerythrocytic protozoan parasites species in cattle, responsible for babesiosis which together with anaplasmosis account for substantial economic losses in the livestock industry worldwide. Anti-tick vaccines are a proved alternative to traditional tick and tick borne diseases control methods but are still limited primarily due to the lack of effective antigens. Subsequently to the identification of antigens the validation is a laborious work often expensive. Tick artificial feeding, is a low cost alternative to test antigens allowing achieving critical data. Herein, R. microplus females were successfully artificially fed using capillary tubes. Calreticulin (CRT) protein, which in a previous study has been identified as being involved in B. bigemina infection in R. annulatus ticks, was expressed as recombinant protein (rCRT) in an E. coli expression system and antibodies raised against rCRT. Anti-rCRT serum was supplemented to a blood meal, offered to partially engorged R. microplus females and their effect in feeding process as well as infection by B. bigemina was analyzed. No significant reductions in tick and egg weight were observed when ticks fed with anti-rCRT serum. Furthermore, B. bigemina infection levels did not show a statistically significant decrease when ticks fed with anti-rCRT antibodies. Results suggest that CRT is not a suitable candidate for cattle vaccination trials. Copyright © 2014 Elsevier GmbH. All rights reserved.

Novel methods for surveying reservoir hosts and vectors of Borrelia burgdorferi in Northern Minnesota

NASA Astrophysics Data System (ADS)

Seifert, Veronica Aili

Lyme disease is the most prevalent tick-borne disease in North America and presents challenges to clinicians, researchers and the public in diagnosis, treatment and prevention. Lyme disease is caused by the spirochete, Borrelia burgdorferi, which is a zoonotic pathogen obligate upon hematophagous arthropod vectors and propagates in small mammal reservoir hosts. Identifying factors governing zoonotic diseases within regions of high-risk provides local health and agricultural agencies with necessary information to formulate public policy and implement treatment protocols to abate the rise and expansion of infectious disease outbreaks. In the United States, the documented primary reservoir host of Lyme disease is the white-footed mouse, Peromyscus leucopus, and the arthropod vector is the deer tick, Ixodes scapularis. Reducing the impact of Lyme disease will need novel methods for identifying both the reservoir host and the tick vector. The reservoir host, Peromyscus leucopus is difficult to distinguish from the virtually identical Peromyscus maniculatus that also is present in Northern Minnesota, a region where Lyme disease is endemic. Collection of the Ixodes tick, the Lyme disease vector, is difficult as this is season dependent and differs from year to year. This study develops new strategies to assess the extent of Borrelia burgdorferi in the local environment of Northern Minnesota. A selective and precise method to identify Peromyscus species was developed. This assay provides a reliable and definitive method to identify the reservoir host, Peromyscus leucopus from a physically identical and sympatric Peromyscus species, Peromyscus maniculatus. A new strategy to collect ticks for measuring the disbursement of Borrelia was employed. Students from local high schools were recruited to collect ticks. This strategy increased the available manpower to cover greater terrain, provided students with valuable experience in research methodology, and highlighted the prospect of increasing community engagement in university-based research projects.

Assessment of Polymicrobial Infections in Ticks in New York State

PubMed Central

Tokarz, Rafal; Jain, Komal; Bennett, Ashlee; Briese, Thomas

2010-01-01

Abstract Ixodes scapularis ticks are clinically important hematophagous vectors. A single tick bite can lead to a polymicrobial infection. We determined the prevalence of polymicrobial infection with Borrelia burgdorferi, Anaplasma phagocytophilum, Babesia microti, Borrelia miyamotoi, and Powassan virus in 286 adult ticks from the two counties in New York State where Lyme disease is endemic, utilizing a MassTag multiplex polymerase chain reaction assay. Seventy-one percent of the ticks harbored at least one organism; 30% had a polymicrobial infection. Infections with three microbes were detected in 5% of the ticks. One tick was infected with four organisms. Our results show that coinfection is a frequent occurrence in ticks in the two counties surveyed. PMID:19725770

Novel Rickettsia and emergent tick-borne pathogens: A molecular survey of ticks and tick-borne pathogens in Shimba Hills National Reserve, Kenya.

PubMed

Mwamuye, Micky M; Kariuki, Edward; Omondi, David; Kabii, James; Odongo, David; Masiga, Daniel; Villinger, Jandouwe

2017-02-01

Ticks are important vectors of emerging and re-emerging zoonoses, the majority of which originate from wildlife. In recent times, this has become a global public health concern that necessitates surveillance of both known and unknown tick-borne pathogens likely to be future disease threats, as well as their tick vectors. We carried out a survey of the diversity of ticks and tick-borne pathogens in Kenya's Shimba Hills National Reserve (SHNR), an area with intensified human-livestock-wildlife interactions, where we collected 4297 questing ticks (209 adult ticks, 586 nymphs and 3502 larvae). We identified four tick species of two genera (Amblyomma eburneum, Amblyomma tholloni, Rhipicephalus maculatus and a novel Rhipicephalus sp.) based on both morphological characteristics and molecular analysis of 16S rRNA, internal transcribed spacer 2 (ITS 2) and cytochrome oxidase subunit 1 (CO1) genes. We pooled the ticks (3-8 adults, 8-15 nymphs or 30 larvae) depending on species and life-cycle stages, and screened for bacterial, arboviral and protozoal pathogens using PCR with high-resolution melting analysis and sequencing of unique melt profiles. We report the first molecular detection of Anaplasma phagocytophilum, a novel Rickettsia-like and Ehrlichia-like species, in Rh. maculatus ticks. We also detected Ehrlichia chaffeensis, Coxiella sp., Rickettsia africae and Theileria velifera in Am. eburneum ticks for the first time. Our findings demonstrate previously unidentified tick-pathogen relationships and a unique tick diversity in the SHNR that may contribute to livestock, and possibly human, morbidity in the region. This study highlights the importance of routine surveillance in similar areas to elucidate disease transmission dynamics, as a critical component to inform the development of better tick-borne disease diagnosis, prevention and control measures. Copyright © 2016 Elsevier GmbH. All rights reserved.

Determinants of Infectivity of Pathogens in Vector Ticks

DTIC Science & Technology

1990-11-15

nature. Y’e compared the development of the Lyme disease spirochete, Borrelia burgdorferi, in subadult rabbit-feeding Ixodes dentatus with that in mouse...the abundance of these vector ticks may effectively be reduced. The spirochetal agent of Lyme disease, Borrelia buradorferi, disseminated from the...11 III. Fine structural evidence for the penetration of the Lyme disease spirochete Borrelia burQdorferi through the gut and salivary tissues

The role of particular ticks developmental stages in the circulation of tick-borne pathogens in Central Europe. 4. Anaplasmataceae

PubMed

Karbowiak, Grzegorz; Biernat, Beata; Stańczak, Joanna; Werszko, Joanna; Wróblewski, Piotr; Szewczyk, Tomasz; Sytykiewicz, Hubert

In Central European conditions, two species of Anaplasmataceae have epidemiological significance – Candidatus Neoehrlichia micurensis and Anaplasma phagocytophilum. Tick Ixodes ricinus is considered as their main vector, wild mammals as the animal reservoir. There is presented the transstadial transmission in ticks, due to the lack of transovarial mode the circulation goes mainly between immature ticks and hosts; pathogen circulates primarily in the cycle: infected rodent → the tick larva → the nymph → the mammal reservoir → the larva of the tick. The tick stages able to effectively infect human are nymphs and adult females, males do not participate in the follow transmission. The summary of available data of different A. phagocytophilum strains associations with different hosts revealed at least few distinct enzootic cycle, concern the same ticks species and different mammal hosts. It is possible to reveal in Central Europe the existence of at least three different epidemiological transmission cycles of A. phagocytophilum. The first cycle involves strains pathogenic for human and identical strains from horses, dogs, cats, wild boars, hedgehogs, possibly red foxes. The second cycle involves deer, European bison and possibly domestic ruminants. The third cycle contains strains from voles, shrew and possibly Apodemus mice. In Western Europe voles might be involved in separate enzootic cycle with Ixodes trianguliceps as the vector.

Application of M13 phage display for identifying immunogenic proteins from tick (Ixodes scapularis) saliva.

PubMed

Becker, Martin; Felsberger, André; Frenzel, André; Shattuck, Wendy M C; Dyer, Megan; Kügler, Jonas; Zantow, Jonas; Mather, Thomas N; Hust, Michael

2015-05-30

Ticks act as vectors for a large number of different pathogens, perhaps most notably Borrelia burgdorferi, the causative agent of Lyme disease. The most prominent tick vector in the United States is the blacklegged tick, Ixodes scapularis. Tick bites are of special public health concern since there are no vaccines available against most tick-transmitted pathogens. Based on the observation that certain non-natural host animals such as guinea pigs or humans can develop adaptive immune responses to tick bites, anti-tick vaccination is a potential approach to tackle health risks associated with tick bites. The aim of this study was to use an oligopeptide phage display strategy to identify immunogenic salivary gland proteins from I. scapularis that are recognized by human immune sera. Oligopeptide libraries were generated from salivary gland mRNA of 18 h fed nymphal I. scapularis. Eight immunogenic oligopeptides were selected using human immune sera. Three selected immunogenic oligopeptides were cloned and produced as recombinant proteins. The immunogenic character of an identified metalloprotease (MP1) was validated with human sera. This enzyme has been described previously and was hypothesized as immunogenic which was confirmed in this study. Interestingly, it also has close homologs in other Ixodes species. An immunogenic protein of I. scapularis was identified by oligopeptide phage display. MP1 is a potential candidate for vaccine development.

Detection of Two Zoonotic Babesia microti Lineages, the Hobetsu and U.S. Lineages, in Two Sympatric Tick Species, Ixodes ovatus and Ixodes persulcatus, Respectively, in Japan

PubMed Central

Tsuji, Masayoshi; Qiang, Wei; Nakao, Minoru; Hirata, Haruyuki; Ishihara, Chiaki

2012-01-01

The species Babesia microti, commonly found in rodents, demonstrates a high degree of genetic diversity. Three lineages, U.S., Kobe, and Hobetsu, are known to have zoonotic potential, but their tick vector(s) in Japan remains to be elucidated. We conducted a field investigation at Nemuro on Hokkaido Island and at Sumoto on Awaji Island, where up to two of the three lineages occur with similar frequencies in reservoirs. By flagging vegetation at these spots and surrounding areas, 4,010 ticks, comprising six species, were collected. A nested PCR that detects the 18S rRNA gene of Babesia species revealed that Ixodes ovatus and I. persulcatus alone were positive. Lineage-specific PCR for rRNA-positive samples demonstrated that I. ovatus and I. persulcatus carried, respectively, the Hobetsu and U.S. parasites. No Kobe-specific DNA was detected. Infected I. ovatus ticks were found at multiple sites, including Nemuro and Sumoto, with minimum infection rates (MIR) of ∼12.3%. However, all I. persulcatus ticks collected within the same regions, a total of 535, were negative for the Hobetsu lineage, indicating that I. ovatus, but not I. persulcatus, was the vector for the lineage. At Nemuro, U.S. lineage was detected in 2 of 139 adult I. persulcatus ticks (MIR, 1.4%), for the first time, while 48 of I. ovatus ticks were negative for that lineage. Laboratory experiments confirmed the transmission of Hobetsu and U.S. parasites to hamsters via I. ovatus and I. persulcatus, respectively. Differences in vector capacity shown by MIRs at Nemuro, where the two species were equally likely to acquire either lineage of parasite, may explain the difference in distribution of Hobetsu throughout Japan and U.S. taxa in Nemuro. These findings are of importance in the assessment of the regional risk for babesiosis in humans. PMID:22389378

Prevention of infectious tick-borne diseases in humans: Comparative studies of the repellency of different dodecanoic acid-formulations against Ixodes ricinus ticks (Acari: Ixodidae)

PubMed Central

Schwantes, Ulrich; Dautel, Hans; Jung, Gerd

2008-01-01

Background Ticks of the species Ixodes ricinus are the main vectors of Lyme Borreliosis and Tick-borne Encephalitis – two rapidly emerging diseases in Europe. Repellents provide a practical means of protection against tick bites and can therefore minimize the transmission of tick-borne diseases. We developed and tested seven different dodecanoic acid (DDA)-formulations for their efficacy in repelling host-seeking nymphs of I. ricinus by laboratory screening. The ultimately selected formulation was then used for comparative investigations of commercially available tick repellents in humans. Methods Laboratory screening tests were performed using the Moving-object (MO) bioassay. All test formulations contained 10% of the naturally occurring active substance DDA and differed only in terms of the quantitative and qualitative composition of inactive ingredients and fragrances. The test procedure used in the human bioassays is a modification of an assay described by the U.S. Environmental Protection Agency and recommended for regulatory affairs. Repellency was computed using the equation: R = 100 - NR/N × 100, where NR is the number of non-repelled ticks, and N is the respective number of control ticks. All investigations were conducted in a controlled laboratory environment offering standardized test conditions. Results All test formulations strongly repelled nymphs of I. ricinus (100-81% protection) as shown by the MO-bioassay. The majority of ticks dropped off the treated surface of the heated rotating drum that served as the attractant (1 mg/cm2 repellent applied). The 10% DDA-based formulation, that produced the best results in laboratory screening, was as effective as the coconut oil-based reference product. The mean protection time of both preparations was generally similar and averaged 8 hours. Repellency investigations in humans showed that the most effective 10% DDA-based formulation (~1.67 mg/cm2 applied) strongly avoided the attachment of I. ricinus nymphs and adults for at least 6 hours. The test repellent always provided protection (83-63%) against I. ricinus nymphs equivalent to the natural coconut oil based reference product and a better protection (88-75%) against adult ticks than the synthetic Icaridin-containing reference repellent. Conclusion We found that the 10% DDA-based formulation (ContraZeck®) is an easily applied and very effective natural repellent against I. ricinus ticks. By reducing the human-vector contact the product minimises the risk of transmission of tick-borne diseases in humans. PMID:18397516

The risk of vector-borne infections in sled dogs associated with existing and new endemic areas in Poland. Part 2: Occurrence and control of babesiosis in a sled dog kennel during a 13-year-long period.

PubMed

Bajer, Anna; Mierzejewska, Ewa J; Rodo, Anna; Welc-Falęciak, Renata

2014-05-28

The achievements of sled dogs in competitions depend both on their training and on their health. Vector-borne infections may lead to anemia, affect joints or heart muscles or even cause death. Canine babesiosis is an emerging, quickly spreading tick-borne disease in Central Europe. Over a 13-year period (2000-2012) the occurrence of babesiosis cases was analyzed in one sled dog kennel situated in Kury, a village near Tłuszcz (N 52°24'56.78″, E 21°30'37.55″) in Central Poland. Twenty cases/episodes of babesiosis were noted among the 10-12 dogs living in the kennel. In 2000-2004, no cases of babesiosis were noted; the first two cases were noted in April 2005. Since that time, only one dog remained uninfected; 6 dogs were infected once, 3 dogs demonstrated symptoms of babesiosis twice, one dog was infected three times and one dog had it five times. Babesiosis appeared in Spring and Autumn, despite the application of anti-tick treatment. No fatal cases were recorded, but in one case a splenectomy was performed due to splenomegaly and spleen rupture. Additionally, the abundance of the main Babesia canis vector, the Dermacentor reticulatus tick, was estimated and monitored during a 4-year period (2008-2012) close to the dog kennel. The abundance of questing ticks was high in 2008 and 2009, but dropped by 10-fold between 2010 and 2012, when the abandoned meadow was cut and used as horse pasture by the local farmer. The regular occurrence, typical seasonal pattern and identification of B. canis DNA in questing tick from this locality confirmed the establishment of a new hyper enzootic region for canine babesiosis. The effectiveness and schedule of applied preventive measures were discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Challenges Posed by Tick-Borne Rickettsiae: Eco-Epidemiology and Public Health Implications

PubMed Central

Eremeeva, Marina E.; Dasch, Gregory A.

2015-01-01

Rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variety of arthropod vectors, primarily by fleas and ticks. Once transmitted or experimentally inoculated into susceptible mammals, some rickettsiae may cause febrile illness of different morbidity and mortality, and which can manifest with different types of exhanthems in humans. However, most rickettsiae circulate in diverse sylvatic or peridomestic reservoirs without having obvious impacts on their vertebrate hosts or affecting humans. We have analyzed the key features of tick-borne maintenance of rickettsiae, which may provide a deeper basis for understanding those complex invertebrate interactions and strategies that have permitted survival and circulation of divergent rickettsiae in nature. Rickettsiae are found in association with a wide range of hard and soft ticks, which feed on very different species of large and small animals. Maintenance of rickettsiae in these vector systems is driven by both vertical and horizontal transmission strategies, but some species of Rickettsia are also known to cause detrimental effects on their arthropod vectors. Contrary to common belief, the role of vertebrate animal hosts in maintenance of rickettsiae is very incompletely understood. Some clearly play only the essential role of providing a blood meal to the tick while other hosts may supply crucial supplemental functions for effective agent transmission by the vectors. This review summarizes the importance of some recent findings with known and new vectors that afford an improved understanding of the eco-epidemiology of rickettsiae; the public health implications of that information for rickettsial diseases are also described. Special attention is paid to the co-circulation of different species and genotypes of rickettsiae within the same endemic areas and how these observations may influence, correctly or incorrectly, trends, and conclusions drawn from the surveillance of rickettsial diseases in humans. PMID:25954738

Challenges posed by tick-borne rickettsiae: eco-epidemiology and public health implications.

PubMed

Eremeeva, Marina E; Dasch, Gregory A

2015-01-01

Rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variety of arthropod vectors, primarily by fleas and ticks. Once transmitted or experimentally inoculated into susceptible mammals, some rickettsiae may cause febrile illness of different morbidity and mortality, and which can manifest with different types of exhanthems in humans. However, most rickettsiae circulate in diverse sylvatic or peridomestic reservoirs without having obvious impacts on their vertebrate hosts or affecting humans. We have analyzed the key features of tick-borne maintenance of rickettsiae, which may provide a deeper basis for understanding those complex invertebrate interactions and strategies that have permitted survival and circulation of divergent rickettsiae in nature. Rickettsiae are found in association with a wide range of hard and soft ticks, which feed on very different species of large and small animals. Maintenance of rickettsiae in these vector systems is driven by both vertical and horizontal transmission strategies, but some species of Rickettsia are also known to cause detrimental effects on their arthropod vectors. Contrary to common belief, the role of vertebrate animal hosts in maintenance of rickettsiae is very incompletely understood. Some clearly play only the essential role of providing a blood meal to the tick while other hosts may supply crucial supplemental functions for effective agent transmission by the vectors. This review summarizes the importance of some recent findings with known and new vectors that afford an improved understanding of the eco-epidemiology of rickettsiae; the public health implications of that information for rickettsial diseases are also described. Special attention is paid to the co-circulation of different species and genotypes of rickettsiae within the same endemic areas and how these observations may influence, correctly or incorrectly, trends, and conclusions drawn from the surveillance of rickettsial diseases in humans.

Climate suitability for European ticks: assessing species distribution models against null models and projection under AR5 climate.

PubMed

Williams, Hefin Wyn; Cross, Dónall Eoin; Crump, Heather Louise; Drost, Cornelis Jan; Thomas, Christopher James

2015-08-28

There is increasing evidence that the geographic distribution of tick species is changing. Whilst correlative Species Distribution Models (SDMs) have been used to predict areas that are potentially suitable for ticks, models have often been assessed without due consideration for spatial patterns in the data that may inflate the influence of predictor variables on species distributions. This study used null models to rigorously evaluate the role of climate and the potential for climate change to affect future climate suitability for eight European tick species, including several important disease vectors. We undertook a comparative assessment of the performance of Maxent and Mahalanobis Distance SDMs based on observed data against those of null models based on null species distributions or null climate data. This enabled the identification of species whose distributions demonstrate a significant association with climate variables. Latest generation (AR5) climate projections were subsequently used to project future climate suitability under four Representative Concentration Pathways (RCPs). Seven out of eight tick species exhibited strong climatic signals within their observed distributions. Future projections intimate varying degrees of northward shift in climate suitability for these tick species, with the greatest shifts forecasted under the most extreme RCPs. Despite the high performance measure obtained for the observed model of Hyalomma lusitanicum, it did not perform significantly better than null models; this may result from the effects of non-climatic factors on its distribution. By comparing observed SDMs with null models, our results allow confidence that we have identified climate signals in tick distributions that are not simply a consequence of spatial patterns in the data. Observed climate-driven SDMs for seven out of eight species performed significantly better than null models, demonstrating the vulnerability of these tick species to the effects of climate change in the future.

Experimental and Natural Infections of Goats with Severe Fever with Thrombocytopenia Syndrome Virus: Evidence for Ticks as Viral Vector.

PubMed

Jiao, Yongjun; Qi, Xian; Liu, Dapeng; Zeng, Xiaoyan; Han, Yewu; Guo, Xiling; Shi, Zhiyang; Wang, Hua; Zhou, Minghao

2015-01-01

Severe fever with thrombocytopenia syndrome virus (SFTSV), the causative agent for the fatal life-threatening infectious disease, severe fever with thrombocytopenia syndrome (SFTS), was first identified in the central and eastern regions of China. Although the viral RNA was detected in free-living and parasitic ticks, the vector for SFTSV remains unsettled. Firstly, an experimental infection study in goats was conducted in a bio-safety level-2 (BSL-2) facility to investigate virus transmission between animals. The results showed that infected animals did not shed virus to the outside through respiratory or digestive tract route, and the control animals did not get infected. Then, a natural infection study was carried out in the SFTSV endemic region. A cohort of naïve goats was used as sentinel animals in the study site. A variety of daily samples including goat sera, ticks and mosquitoes were collected for viral RNA and antibody (from serum only) detection, and virus isolation. We detected viral RNA from free-living and parasitic ticks rather than mosquitoes, and from goats after ticks' infestation. We also observed sero-conversion in all members of the animal cohort subsequently. The S segment sequences of the two recovered viral isolates from one infected goat and its parasitic ticks showed a 100% homology at the nucleic acid level. In our natural infection study, close contact between goats does not appear to transmit SFTSV, however, the naïve animals were infected after ticks' infestation and two viral isolates derived from an infected goat and its parasitic ticks shared 100% of sequence identity. These data demonstrate that the etiologic agent for goat cohort's natural infection comes from environmental factors. Of these, ticks, especially the predominant species Haemaphysalis longicornis, probably act as vector for this pathogen. The findings in this study may help local health authorities formulate and focus preventive measures to contain this infection.

What's eating you? lone star tick (Amblyomma americanum).

PubMed

Reynolds, H Harris; Elston, Dirk M

2017-02-01

Amblyomma americanum , also known as the lone star tick, is found in much of the eastern United States. Since the mid-20th century, the lone star tick has been implicated in human disease. Today, A americanum remains an important vector for tick-borne illness. In addition to others, species of Rickettsia , Ehrlichia , and Borrelia are all transmitted by the lone star tick. Recently described conditions such as Southern tick-associated rash illness and anaphylaxis to red meat following tick bites have been attributed to the lone star tick. Impressive local reactions also can result after bites from A americanum . Early treatment of tick-borne illness is crucial to ensure good patient outcomes. Tick-control measures also are an important part of disease management in endemic areas. We discuss the tick's biology, human illnesses associated with A americanum , and methods to control tick numbers and eliminate disease in local reservoirs.

Detection of human bacterial pathogens in ticks collected from Louisiana black bears (Ursus americanus luteolus)

PubMed Central

Leydet, Brian F.; Liang, Fang-Ting

2013-01-01

There are 4 major human-biting tick species in the northeastern United States, which include: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis. The black bear is a large mammal that has been shown to be parasitized by all the aforementioned ticks. We investigated the bacterial infections in ticks collected from Louisiana black bears (Ursus americanus subspecies luteolus). Eighty-six ticks were collected from 17 black bears in Louisiana from June 2010 to March 2011. All 4 common human-biting tick species were represented. Each tick was subjected to polymerase chain reaction (PCR) targeting select bacterial pathogens and symbionts. Bacterial DNA was detected in 62% of ticks (n=53). Rickettsia parkeri, the causative agent of an emerging spotted fever group rickettsiosis, was identified in 66% of A. maculatum, 28% of D. variabilis, and 11% of I. scapularis. The Lyme disease bacterium, Borrelia burgdorferi, was detected in 2 I. scapularis, while one Am. americanum was positive for Borrelia bissettii, a putative human pathogen. The rickettsial endosymbionts Candidatus Rickettsia andeanae, rickettsial endosymbiont of I. scapularis, and Rickettsia amblyommii were detected in their common tick hosts at 21%, 39%, and 60%, respectively. All ticks were PCR-negative for Anaplasma phagocytophilum, Ehrlichia spp., and Babesia microti. This is the first reported detection of R. parkeri in vector ticks in Louisiana; we also report the novel association of R. parkeri with I. scapularis. Detection of both R. parkeri and Bo. burgdorferi in their respective vectors in Louisiana demands further investigation to determine potential for human exposure to these pathogens. PMID:23415850

Catalase is a determinant of the colonization and transovarial transmission of Rickettsia parkeri in the Gulf Coast tick Amblyomma maculatum.

PubMed

Budachetri, K; Kumar, D; Karim, S

2017-08-01

The Gulf Coast tick (Amblyomma maculatum) has evolved as a competent vector of the spotted-fever group rickettsia, Rickettsia parkeri. In this study, the functional role of catalase, an enzyme responsible for the degradation of toxic hydrogen peroxide, in the colonization of the tick vector by R. parkeri and transovarial transmission of this pathogen to the next tick generation, was investigated. Catalase gene (CAT) expression in midgut, salivary glands and ovarian tissues exhibited a 2-11-fold increase in transcription level upon R. parkeri infection. Depletion of CAT transcripts using an RNA-interference approach significantly reduced R. parkeri infection levels in midgut and salivary gland tissues by 53-63%. The role of CAT in transovarial transmission of R. parkeri was confirmed by simultaneously blocking the transcript and the enzyme by injecting double-stranded RNA for CAT and a catalase inhibitor (3-amino-1,2,4-triazole) into gravid females. Simultaneous inhibition of the CAT transcript and the enzyme significantly reduced the egg conversion ratio with a 44% reduction of R. parkeri transovarial transmission. These data suggest that catalase is required for rickettsial colonization of the tick vector and transovarial transmission to the next generation. © 2017 The Royal Entomological Society.

Bacteria associated with Amblyomma cajennense tick eggs

PubMed Central

Machado-Ferreira, Erik; Vizzoni, Vinicius Figueiredo; Piesman, Joseph; Gazeta, Gilberto Salles; Soares, Carlos Augusto Gomes

2015-01-01

Abstract Ticks represent a large group of pathogen vectors that blood feed on a diversity of hosts. In the Americas, the Ixodidae ticks Amblyomma cajennense are responsible for severe impact on livestock and public health. In the present work, we present the isolation and molecular identification of a group of culturable bacteria associated with A. cajennense eggs from females sampled in distinct geographical sites in southeastern Brazil. Additional comparative analysis of the culturable bacteria from Anocentor nitens, Rhipicephalus sanguineus and Ixodes scapularis tick eggs were also performed. 16S rRNA gene sequence analyses identified 17 different bacterial types identified as Serratia marcescens, Stenotrophomonas maltophilia, Pseudomonas fluorescens, Enterobacter spp., Micrococcus luteus, Ochrobactrum anthropi, Bacillus cereus and Staphylococcus spp., distributed in 12 phylogroups. Staphylococcus spp., especially S. sciuri, was the most prevalent bacteria associated with A. cajennense eggs, occurring in 65% of the samples and also frequently observed infecting A. nitens eggs. S. maltophilia, S. marcescens and B. cereus occurred infecting eggs derived from specific sampling sites, but in all cases rising almost as pure cultures from infected A. cajennense eggs. The potential role of these bacterial associations is discussed and they possibly represent new targets for biological control strategies of ticks and tick borne diseases. PMID:26537602

Genomic insights into the Ixodes scapularis tick vector of Lyme disease.

PubMed

Gulia-Nuss, Monika; Nuss, Andrew B; Meyer, Jason M; Sonenshine, Daniel E; Roe, R Michael; Waterhouse, Robert M; Sattelle, David B; de la Fuente, José; Ribeiro, Jose M; Megy, Karine; Thimmapuram, Jyothi; Miller, Jason R; Walenz, Brian P; Koren, Sergey; Hostetler, Jessica B; Thiagarajan, Mathangi; Joardar, Vinita S; Hannick, Linda I; Bidwell, Shelby; Hammond, Martin P; Young, Sarah; Zeng, Qiandong; Abrudan, Jenica L; Almeida, Francisca C; Ayllón, Nieves; Bhide, Ketaki; Bissinger, Brooke W; Bonzon-Kulichenko, Elena; Buckingham, Steven D; Caffrey, Daniel R; Caimano, Melissa J; Croset, Vincent; Driscoll, Timothy; Gilbert, Don; Gillespie, Joseph J; Giraldo-Calderón, Gloria I; Grabowski, Jeffrey M; Jiang, David; Khalil, Sayed M S; Kim, Donghun; Kocan, Katherine M; Koči, Juraj; Kuhn, Richard J; Kurtti, Timothy J; Lees, Kristin; Lang, Emma G; Kennedy, Ryan C; Kwon, Hyeogsun; Perera, Rushika; Qi, Yumin; Radolf, Justin D; Sakamoto, Joyce M; Sánchez-Gracia, Alejandro; Severo, Maiara S; Silverman, Neal; Šimo, Ladislav; Tojo, Marta; Tornador, Cristian; Van Zee, Janice P; Vázquez, Jesús; Vieira, Filipe G; Villar, Margarita; Wespiser, Adam R; Yang, Yunlong; Zhu, Jiwei; Arensburger, Peter; Pietrantonio, Patricia V; Barker, Stephen C; Shao, Renfu; Zdobnov, Evgeny M; Hauser, Frank; Grimmelikhuijzen, Cornelis J P; Park, Yoonseong; Rozas, Julio; Benton, Richard; Pedra, Joao H F; Nelson, David R; Unger, Maria F; Tubio, Jose M C; Tu, Zhijian; Robertson, Hugh M; Shumway, Martin; Sutton, Granger; Wortman, Jennifer R; Lawson, Daniel; Wikel, Stephen K; Nene, Vishvanath M; Fraser, Claire M; Collins, Frank H; Birren, Bruce; Nelson, Karen E; Caler, Elisabet; Hill, Catherine A

2016-02-09

Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick-host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host 'questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.

Powassan Virus-A New Reemerging Tick-Borne Disease.

PubMed

Fatmi, Syed Soheb; Zehra, Rija; Carpenter, David O

2017-01-01

Powassan virus is a neurovirulent flavivirus consisting of two lineages causing meningoencephalitis. It is the only member of the tick-borne encephalitis serogroup which is present in mainland North America. With a total number of 27 cases from 1958 to 1998 and 98 cases from 1999 to 2016, reported cases have increased by 671% over the last 18 years. Powassan infection is transmitted by different tick species in different geographical regions. Ixodes scapularis is the primary vector that transmits the virus on the East Coast of US and Ixodes cookei in the Midwest and Canada, while Hemaphysalis longicornis is the vector in Russia. Powassan has no singular pathognomonic finding and presents with a wide spectrum of symptoms including severe neurological symptoms. The clinical challenge lies within the management of the disease as there is no standard diagnostic protocol and most cases are only diagnosed after a patient goes through an extensive workup for other infectious disease. The diagnosis is established by a combination of imaging and serologic tests. In case of Powassan meningoencephalitis, computed tomography scan and magnetic resonance imaging show vascular insults, which are also seen in cases of tick-borne encephalitis virus, another flavivirus of medical importance. Serologic tests are the gold standard for diagnosis, although testing is not widely available and only state health departments and Center for Disease Control and Prevention can perform Powassan-specific IgM antibody testing utilizing enzyme-linked immunosorbent assay and immunofluorescence antibody. Powassan is also of veterinary medical importance. Wildlife animals act as a reservoir to the pathogens, hence possessing threat to humans and domestic animals. This review highlights Powassan's neurotropic presentation, epidemiology, diagnostic challenges, and prevalence. Strong emphasis is placed on establishing diagnostic protocols, widespread Powassan-specific IgM testing, role of the vector in disease presentation, and necessary preventive research.

Assessment of Climate Change and Vector-borne Diseases in the United States

NASA Astrophysics Data System (ADS)

Monaghan, A. J.; Beard, C. B.; Eisen, R. J.; Barker, C. M.; Garofalo, J.; Hahn, M.; Hayden, M.; Ogden, N.; Schramm, P.

2016-12-01

Vector-borne diseases are illnesses that are transmitted by vectors, which include mosquitoes, ticks, and fleas. The seasonality, distribution, and prevalence of vector-borne diseases are influenced significantly by climate factors, primarily high and low temperature extremes and precipitation patterns. In this presentation we summarize key findings from Chapter 5 ("Vector-borne Diseases") of the recently published USGCRP Scientific Assessment of the Impacts of Climate Change on Human Health in the United States. Climate change is expected to alter geographic and seasonal distributions of vectors and vector-borne diseases, leading to earlier activity and northward range expansion of ticks capable of carrying the bacteria that cause Lyme disease and other pathogens, and influencing the distribution, abundance and prevalence of infection in mosquitoes that transmit West Nile virus and other pathogens. The emergence or reemergence of vector-borne pathogens is also likely.

Modeling the geographic distribution of Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae) in the contiguous United States

USGS Publications Warehouse

Hahn, Micah; Jarnevich, Catherine S.; Monaghan, Andrew J.; Eisen, Rebecca J.

2016-01-01

In addition to serving as vectors of several other human pathogens, the black-legged tick, Ixodes scapularis Say, and western black-legged tick, Ixodes pacificus Cooley and Kohls, are the primary vectors of the spirochete (Borrelia burgdorferi ) that causes Lyme disease, the most common vector-borne disease in the United States. Over the past two decades, the geographic range of I. pacificus has changed modestly while, in contrast, the I. scapularis range has expanded substantially, which likely contributes to the concurrent expansion in the distribution of human Lyme disease cases in the Northeastern, North-Central and Mid-Atlantic states. Identifying counties that contain suitable habitat for these ticks that have not yet reported established vector populations can aid in targeting limited vector surveillance resources to areas where tick invasion and potential human risk are likely to occur. We used county-level vector distribution information and ensemble modeling to map the potential distribution of I. scapularis and I. pacificus in the contiguous United States as a function of climate, elevation, and forest cover. Results show that I. pacificus is currently present within much of the range classified by our model as suitable for establishment. In contrast, environmental conditions are suitable for I. scapularis to continue expanding its range into northwestern Minnesota, central and northern Michigan, within the Ohio River Valley, and inland from the southeastern and Gulf coasts. Overall, our ensemble models show suitable habitat for I. scapularis in 441 eastern counties and for I. pacificus in 11 western counties where surveillance records have not yet supported classification of the counties as established.

[Amblyomma spp. case related to overseas travel].

PubMed

Beyhan, Yunus Emre; Mungan, Mesut; Babür, Cahit

2014-01-01

Ticks are a threat to human health by blood sucking and vectoring many disease agents. Tick-borne diseases are seen all over the world and play an important role in the dissemination of diseases. Although many of the tick species are present in Turkey, Amblyomma genus is seen more in South America and Africa. In this case,a person returning to the country after travelling to Africa who presented to the hospital complaining of tick bites and brought ticks to the parasitology laboratory was identified as Ablyomma spp. nymph. This case is a report concerning care of tick bites when travelling abroad and shows that these ticks can transmit disease agents from abroad.

A Cysteine Protease Is Critical for Babesia spp. Transmission in Haemaphysalis Ticks

PubMed Central

Tsuji, Naotoshi; Miyoshi, Takeharu; Battsetseg, Badger; Matsuo, Tomohide; Xuan, Xuenan; Fujisaki, Kozo

2008-01-01

Vector ticks possess a unique system that enables them to digest large amounts of host blood and to transmit various animal and human pathogens, suggesting the existence of evolutionally acquired proteolytic mechanisms. We report here the molecular and reverse genetic characterization of a multifunctional cysteine protease, longipain, from the babesial parasite vector tick Haemaphysalis longicornis. Longipain shares structural similarity with papain-family cysteine proteases obtained from invertebrates and vertebrates. Endogenous longipain was mainly expressed in the midgut epithelium and was specifically localized at lysosomal vacuoles and possibly released into the lumen. Its expression was up-regulated by host blood feeding. Enzymatic functional assays using in vitro and in vivo substrates revealed that longipain hydrolysis occurs over a broad range of pH and temperature. Haemoparasiticidal assays showed that longipain dose-dependently killed tick-borne Babesia parasites, and its babesiacidal effect occurred via specific adherence to the parasite membranes. Disruption of endogenous longipain by RNA interference revealed that longipain is involved in the digestion of the host blood meal. In addition, the knockdown ticks contained an increased number of parasites, suggesting that longipain exerts a killing effect against the midgut-stage Babesia parasites in ticks. Our results suggest that longipain is essential for tick survival, and may have a role in controlling the transmission of tick-transmittable Babesia parasites. PMID:18483546

Molecular analysis of Crimean-Congo hemorrhagic fever virus and Rickettsia in Hyalomma marginatum ticks removed from patients (Spain) and birds (Spain and Morocco), 2009-2015.

PubMed

Palomar, Ana M; Portillo, Aránzazu; Mazuelas, David; Roncero, Lidia; Arizaga, Juan; Crespo, Ariñe; Gutiérrez, Óscar; Márquez, Francisco J; Cuadrado, Juan F; Eiros, José M; Oteo, José A

2016-07-01

Crimean-Congo hemorrhagic fever virus (CCHFV) was detected in Spain in 2010. The presence of CCHFV in Hyalomma marginatum ticks from migratory birds passing through Morocco during the spring migration strengthened the hypothesis of the arrival of infected ticks transported by birds to the Iberian Peninsula. Furthermore, Hyalomma species are vectors of bacterial infections such as spotted fever rickettsioses. CCHFV and Rickettsia were screened in Hyalomma ticks from Spain attached to patients (n=12) and birds (n=149). In addition, Rickettsia was investigated in 52 Hyalomma ticks from Morocco (previously reported as CCHFV-infected). No sample collected in Spain showed an infection with CCHFV. Two ticks removed from patients (16.7%), as well as 47 (31.5%) and 4 (7.7%) from birds, collected in Spain and Morocco respectively, were infected with Rickettsia aeschlimannii. Rickettsia sibirica subsp. mongolitimonae was also found in 2 ticks from birds collected in Spain (1.3%). The risk of CCHFV-infected ticks attached to migratory birds to reach the North of Spain is low. This study corroborates the presence of R. aeschlimannii in Spain and Morocco, and supports that H. marginatum can be a potential vector of R. sibirica subsp. mongolitimonae in the Iberian Peninsula. Copyright © 2016 Elsevier GmbH. All rights reserved.

Quantitative PCR-based parasite burden estimation of Babesia gibsoni in the vector tick, Haemaphysalis longicornis (Acari: Ixodidae), fed on an experimentally infected dog.

PubMed

Hatta, Takeshi; Matsubayashi, Makoto; Miyoshi, Takeharu; Islam, Khyrul; Alim, M Abdul; Anisuzzaman; Yamaji, Kayoko; Fujisaki, Kozo; Tsuji, Naotoshi

2013-01-31

Most causative agents of babesiosis, Babesia parasites, are transmitted transovarially in ixodid ticks. In this study, B. gibsoni, the causative agent of canine babesiosis which has transovarial transmission, was detected in tissues of the vector tick, Haemaphysalis longicornis using a modified quantitative PCR assay. Conventional PCR results showed that the newly designed primer set, which amplifies a 143-bp fragment of rhoptry-associated protein-1 (BgRAP-1) gene in B. gibsoni, was 100 times more sensitive than primers targeting P18 gene encoding 18 kDa protein of B. gibsoni, which was recently renamed as thrombospondin related adhesive protein (BgTRAP) gene, in an artificially generated sample solution containing metagenomic DNA (B. gibsoni DNA extracted from infected dog blood mixed with tick DNA). The TaqMan probe-based quantitative PCR (qPCR) for BgRAP-1 could also detect infected RBCs (iRBCs) at levels of 3.5 × 10(5) to 3.5 × 10(1)/μl, a range that is broader than that of a past SYBR Green-based qPCR method for P18/BgTRAP, which had a detection limit of 3.5 × 10(3) iRBCs/μl. Using this qPCR assay, we attempted to quantify the B. gibsoni burden in tick ovaries and embryonated eggs. Levels of infection were normalized to the copy number of tick's genomic DNA fragment of ribosomal DNA internal transcribed spacer region 2 (ITS2) for the standardization. According to this, low levels of parasite burden were quantified in ovaries and eggs. This detection system is sensitive and is recommended as a tool for elucidating the biological interactions between the vector tick H. longicornis and the parasite, B. gibsoni.

Identification and characterization of a histamine-binding lipocalin-like molecule from the relapsing fever tick Ornithodoros turicata.

PubMed

Neelakanta, G; Sultana, H; Sonenshine, D E; Andersen, J F

2018-04-01

Lipocalins are low molecular weight membrane transporters that are abundantly expressed in the salivary glands and other tissues of ticks. In this study, we identified a lipocalin-like molecule, designated as otlip, from the soft ticks Ornithodoros turicata, the vector for the relapsing fever causing spirochete Borrelia turicatae. We noted that the expression of otlip was developmentally regulated, with adult ticks expressing significantly higher levels in comparison to the larvae or nymphal ticks. Expression of otlip was evident in both fed and unfed O. turicata ticks, with significantly increased expression in the salivary glands in comparison to the midgut or ovary tissues. High conservation of the biogenic amine-binding motif was evident in the deduced primary amino acid sequence of Otlip. Protein modelling of Otlip revealed conservation of most of the residues involved in binding histamine or serotonin ligand. In vitro assays demonstrated binding of recombinant Otlip with histamine. Furthermore, prediction of post-translational modifications revealed that Otlip contained phosphorylation and myristoylation sites. Taken together, our study not only provides evidence for the presence of a lipocalin-like molecule in O. turicata ticks but also suggests a role for this molecule in the salivary glands of this medically important vector. © 2017 The Royal Entomological Society.

Rhipicephalus turanicus, a new vector of Hepatozoon canis.

PubMed

Giannelli, Alessio; Lia, Riccardo Paolo; Annoscia, Giada; Buonavoglia, Canio; Lorusso, Eleonora; Dantas-Torres, Filipe; Baneth, Gad; Otranto, Domenico

2017-05-01

The distribution of Hepatozoon canis mainly encompasses areas where its main tick vector, Rhipicephalus sanguineus sensu lato, is present. However, the detection of this pathogen in dogs, foxes and golden jackals well outside the areas inhabited by this tick species reinforced the hypothesis that additional ixodids are involved in the life cycle and transmission of this protozoon. The present study provides, for the first time, data supporting the sporogonic development of H. canis in specimens of Rhipicephalus turanicus collected from a naturally infected fox from southern Italy. The epidemiological role of R. turanicus as a vector of H. canis is discussed, along with information on the potential use of cell cultures for the experimental infection with H. canis sporozoites. The in vitro infection of canine leucocytes by sporozoites from ticks is proposed as a potential tool for future in-depth studies on the biology of H. canis.

Tick Salivary Cholinesterase: A Probable Immunomodulator of Host-parasite Interactions.

PubMed

Temeyer, Kevin B; Tuckow, Alexander P

2016-05-01

The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), is the most economically important cattle ectoparasite in the world. Rhipicephalus microplus and Rhipicephalus annulatus (Say) continue to threaten U.S. cattle producers despite eradication and an importation barrier based on inspection, dipping of imported cattle in organophosphate (OP) acaricide, and quarantine of infested premises. OP acaricides inhibit acetylcholinesterase (AChE), essential to tick central nervous system function. Unlike vertebrates, ticks possess at least three genes encoding AChEs, differing in amino acid sequence and biochemical properties. Genomic analyses of R. microplus and the related tick, Ixodes scapularis, suggest that ticks contain many genes encoding different AChEs. This work is the first report of a salivary cholinesterase (ChE) activity in R. microplus, and discusses complexity of the cholinergic system in ticks and significance of tick salivary ChE at the tick-host interface. It further provides three hypotheses that the salivary ChE plausibly functions 1) to reduce presence of potentially toxic acetylcholine present in the large bloodmeal imbibed during rapid engorgement, 2) to modulate the immune response (innate and/or acquired) of the host to tick antigens, and 3) to influence transmission and establishment of pathogens within the host animal. Ticks are vectors for a greater number and variety of pathogens than any other parasite, and are second only to mosquitoes (owing to malaria) as vectors of serious human disease. Saliva-assisted transmission (SAT) of pathogens is well-known; however, the salivary components participating in the SAT process remain to be elucidated. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.

Babesia spp. identified by PCR in ticks collected from domestic and wild ruminants in southern Switzerland.

PubMed

Hilpertshauser, Heidi; Deplazes, Peter; Schnyder, Manuela; Gern, Lise; Mathis, Alexander

2006-10-01

Concurrent infections with vector-borne pathogens affected a cattle herd in Switzerland, and one of the pathogens was identified as Babesia bigemina, which had never been observed in this country before. Therefore, a survey of the occurrence of ruminant Babesia spp. and their tick vectors in Switzerland was conducted. A total of 2,017 ticks were collected from sheep, goats, cattle, and wild ruminants (deer, roe deer, and chamois) in southern parts of Switzerland and identified morphologically. The vast majority of the ticks (99.2%) were Ixodes ricinus, but 14 ticks from sheep and goats were identified as Dermacentor marginatus and two ticks from wild ruminants were identified as Hemaphysalis punctata. PCR analyses of 700 ticks revealed the presence of Babesia divergens (n = 6), Babesia sp. genotype EU1 (n = 14), and B. major (n = 2), whose suggested occurrence was confirmed in this study by molecular analysis, and the presence of novel Babesia sp. genotype CH1 (n = 4), which is closely related to B. odocoilei and to Babesia sp. genotype RD61 reported from North America. The identification of B. divergens and B. major in ticks collected from wild ruminants cast doubt on the postulated strict host specificity of these bovine Babesia species. Furthermore, the zoonotic Babesia sp. genotype EU1 was detected in ticks collected from domestic animals but was obtained predominantly from ticks collected from wild ruminants. More than one tick containing DNA of different Babesia spp. were collected from two red deer. Hence, the role of these game animals as reservoir hosts of Babesia spp. seems to be important but requires further investigation.

Prevention of tick-borne diseases.

PubMed

Piesman, Joseph; Eisen, Lars

2008-01-01

Tick-borne diseases are on the rise. Lyme borreliosis is prevalent throughout the Northern Hemisphere, and the same Ixodes tick species transmitting the etiologic agents of this disease also serve as vectors of pathogens causing human babesiosis, human granulocytic anaplasmosis, and tick-borne encephalitis. Recently, several novel agents of rickettsial diseases have been described. Despite an explosion of knowledge in the fields of tick biology, genetics, molecular biology, and immunology, transitional research leading to widely applied public health measures to combat tick-borne diseases has not been successful. Except for the vaccine against tick-borne encephalitis virus, and a brief campaign to reduce this disease in the former Soviet Union through widespread application of DDT, success stories in the fight against tick-borne diseases are lacking. Both new approaches to tick and pathogen control and novel ways of translating research findings into practical control measures are needed to prevent tick-borne diseases in the twenty-first century.

Mutation in the sodium channel gene corresponds with phenotypic resistance of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) to pyrethroids

USDA-ARS?s Scientific Manuscript database

The brown dog tick, Rhipicephalus sanguineus sensu lato, is a cosmopolitan ectoparasite and vector of pathogens that kill humans and animals. Pyrethroids represent a class of synthetic acaricides that have been used intensely to try to control the brown dog tick and mitigate the risk of tick-borne d...

Implications of climate change on the distribution of the tick vector Ixodes scapularis and risk for Lyme disease in the Texas-Mexico transboundary region

USDA-ARS?s Scientific Manuscript database

Disease risk maps are important tools that help ascertain the likelihood of exposure to specific infectious agents. Understanding how climate change may affect the suitability of habitats for ticks will improve the accuracy of risk maps of tick-borne pathogen transmission in humans and domestic anim...

Experimental transmission of Powassan virus (Flaviviridae) by Ixodes scapularis ticks (Acari:Ixodidae).

PubMed

Costero, A; Grayson, M A

1996-11-01

Transmission experiments were performed with Ixodes scapularis ticks from an uninfected laboratory colony. Immature and adult ticks were exposed to Powassan (POW) viremic hamsters and rabbits, respectively. Oral infection rates for engorged larvae, nymphs and females fed on POW-infected hosts were 10%, 40%, and 57%, respectively. Transstadial transmission rates for nymphs exposed to POW virus as larvae, adults exposed as larvae, and adults exposed as nymphs, were 9.5%, 10%, and 54%, respectively. Evidence of transovarial transmission occurred when two uninfected hamsters, exposed to F2 larvae and nymphs originally exposed to POW virus in the F1 nymphal stage, seroconverted to POW virus with hemagglutination inhibition titers of 80 and 5,120, respectively; the transovarial transmission rate was 16.6%. All developmental stages were able to transmit virus orally to uninfected hosts regardless of when the ticks were originally exposed to the virus. These results suggest that I. scapularis is a competent vector of POW virus under experimental conditions.

Pathogen-mediated manipulation of arthropod microbiota to promote infection

PubMed Central

Abraham, Nabil M.; Liu, Lei; Jutras, Brandon Lyon; Yadav, Akhilesh K.; Narasimhan, Sukanya; Gopalakrishnan, Vissagan; Ansari, Juliana M.; Jefferson, Kimberly K.; Cava, Felipe; Jacobs-Wagner, Christine; Fikrig, Erol

2017-01-01

Arthropods transmit diverse infectious agents; however, the ways microbes influence their vector to enhance colonization are poorly understood. Ixodes scapularis ticks harbor numerous human pathogens, including Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis. We now demonstrate that A. phagocytophilum modifies the I. scapularis microbiota to more efficiently infect the tick. A. phagocytophilum induces ticks to express Ixodes scapularis antifreeze glycoprotein (iafgp), which encodes a protein with several properties, including the ability to alter bacterial biofilm formation. IAFGP thereby perturbs the tick gut microbiota, which influences the integrity of the peritrophic matrix and gut barrier—critical obstacles for Anaplasma colonization. Mechanistically, IAFGP binds the terminal d-alanine residue of the pentapeptide chain of bacterial peptidoglycan, resulting in altered permeability and the capacity of bacteria to form biofilms. These data elucidate the molecular mechanisms by which a human pathogen appropriates an arthropod antibacterial protein to alter the gut microbiota and more effectively colonize the vector. PMID:28096373

Diapause in ticks of the medically important Ixodes ricinus species complex

PubMed Central

Gray, Jeremy S.; Kahl, Olaf; Lane, Robert S.; Levin, Michael L.; Tsao, Jean I.

2017-01-01

Four members of the Ixodes ricinus species complex, Ixodes pacificus, Ixodes persulcatus, Ixodes ricinus and Ixodes scapularis, have, between them, a worldwide distribution within the northern hemisphere. They are responsible for the transmission of several animal and human pathogens, including the causal agents of Lyme borreliosis, tick-borne encephalitis, human granulocytic anaplasmosis and human babesiosis. Despite the importance of these ticks as vectors, the knowledge and understanding of the role that diapause plays in their complex life cycles are confused and incomplete. In view of the continuing geographic spread of these tick species, as well as the effects of climate change on vector-borne diseases, it is timely encourage research on diapause phenomena to improve understanding of their biology and of pathogen transmission dynamics. In our review we seek to clarify thinking on the topic and to address gaps in our knowledge that require the attention of researchers. PMID:27263092

Vector-borne diseases and climate change: a European perspective

PubMed Central

Suk, Jonathan E

2017-01-01

Abstract Climate change has already impacted the transmission of a wide range of vector-borne diseases in Europe, and it will continue to do so in the coming decades. Climate change has been implicated in the observed shift of ticks to elevated altitudes and latitudes, notably including the Ixodes ricinus tick species that is a vector for Lyme borreliosis and tick-borne encephalitis. Climate change is also thought to have been a factor in the expansion of other important disease vectors in Europe: Aedes albopictus (the Asian tiger mosquito), which transmits diseases such as Zika, dengue and chikungunya, and Phlebotomus sandfly species, which transmits diseases including Leishmaniasis. In addition, highly elevated temperatures in the summer of 2010 have been associated with an epidemic of West Nile Fever in Southeast Europe and subsequent outbreaks have been linked to summer temperature anomalies. Future climate-sensitive health impacts are challenging to project quantitatively, in part due to the intricate interplay between non-climatic and climatic drivers, weather-sensitive pathogens and climate-change adaptation. Moreover, globalisation and international air travel contribute to pathogen and vector dispersion internationally. Nevertheless, monitoring forecasts of meteorological conditions can help detect epidemic precursors of vector-borne disease outbreaks and serve as early warning systems for risk reduction. PMID:29149298

Vector-borne diseases and climate change: a European perspective.

PubMed

Semenza, Jan C; Suk, Jonathan E

2018-02-01

Climate change has already impacted the transmission of a wide range of vector-borne diseases in Europe, and it will continue to do so in the coming decades. Climate change has been implicated in the observed shift of ticks to elevated altitudes and latitudes, notably including the Ixodes ricinus tick species that is a vector for Lyme borreliosis and tick-borne encephalitis. Climate change is also thought to have been a factor in the expansion of other important disease vectors in Europe: Aedes albopictus (the Asian tiger mosquito), which transmits diseases such as Zika, dengue and chikungunya, and Phlebotomus sandfly species, which transmits diseases including Leishmaniasis. In addition, highly elevated temperatures in the summer of 2010 have been associated with an epidemic of West Nile Fever in Southeast Europe and subsequent outbreaks have been linked to summer temperature anomalies. Future climate-sensitive health impacts are challenging to project quantitatively, in part due to the intricate interplay between non-climatic and climatic drivers, weather-sensitive pathogens and climate-change adaptation. Moreover, globalisation and international air travel contribute to pathogen and vector dispersion internationally. Nevertheless, monitoring forecasts of meteorological conditions can help detect epidemic precursors of vector-borne disease outbreaks and serve as early warning systems for risk reduction. © FEMS 2017.

Reducing Tick-Borne Disease in Alabama: Linking Health Risk Perception with Spatial Analysis Using the NASA Earth Observing System

NASA Technical Reports Server (NTRS)

Hemmings, S.; Renneboog, N.; Firsing, S.; Capilouto, E.; Harden, J.; Hyden, R.; Tipre, M.; Zhang, Y.

2010-01-01

Lyme disease (LD) accounts for most vector-borne disease reports in the U.S., and although its existence in Alabama remains controversial, other tick-borne illnesses (TBI) such as Southern Tick-Associated Rash Illness (STARI) pose a health concern in the state. Phase One of the Marshall Space Flight Center-UAB DEVELOP study of TBI identified the presence of the chain of infection for LD (Ixodes scapularis ticks carrying Borrelia burgdorferi bacteria) and STARI (Amblyomma americanum ticks and an as-yet-unconfirmed agent) in Alabama. Both LD and STARI are associated with the development of erythema migrans rashes around an infected tick bite, and while treatable with oral antibiotics, a review of educational resources available to state residents revealed low levels of prevention information. To improve prevention, recognition, and treatment of TBI in Alabama, Phase Two builds a health communication campaign based on vector habitat mapping and risk perception assessment. NASA Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite imagery identified likely tick habitats using remotely sensed measurements of vegetation vigor (Normalized Difference Vegetation Index) and soil moisture. Likely tick habitats, identified as those containing both high vegetation density and soil moisture, included Oak Mountain State Park, Bankhead National Forest, and Talladega National Forest. To target a high-risk group -- outdoor recreation program participants at Alabama universities -- the study developed a behavior survey instrument based on existing studies of LD risk factors and theoretical constructs from the Social Ecological Model and Health Belief Model. The survey instrument was amended to include geographic variables in the assessment of TBI knowledge, attitudes, and prevention behaviors, and the vector habitat model will be expanded to incorporate additional environmental variables and in situ data. Remotely sensed environmental data combined with risk perception assessments inform an ongoing outreach campaign consisting of stakeholder meetings and educational seminars.

Prevalence of tick-borne encephalitis virus in ixodid ticks collected from the republic of Korea during 2011-2012.

PubMed

Yun, Seok-Min; Song, Bong Gu; Choi, Wooyoung; Park, Won Il; Kim, Sung Yun; Roh, Jong Yul; Ryou, Jungsang; Ju, Young Ran; Park, Chan; Shin, E-Hyun

2012-12-01

In this study, we demonstrated that TBEV-infected ticks have been distributed in the ROK, combined with our previous results. These results suggest that TBEV may exist in the ROK, and H. longicornis, H. flava, and I. nipponensis may be potential vectors of TBEV. In addition, these results emphasize the need for further epidemiological research of TBEV. We examined for the presence of RNA of TBEV by reverse transcriptase-nested polymerase chain reaction (RT-nested PCR) using ixodid ticks captured in 25 localities of 10 provinces. Ticks were collected by the flagging and dragging method or using sentinel BG traps at forests, grass thickets, and grassland. A total of 13,053 ticks belonging to two genera and four species were collected and pooled (1292 pools), according to collection site, species of tick, and developmental stage. Among 1292 pools, the envelope (E) protein gene of TBEV was detected using RT-nested PCR in 10 pools (3 pools of the 1,331 adult ticks and 7 pools of the 11,169 nymph ticks) collected from Gangwon-do province, Jeonrabuk-do province, and Jeju Island. The minimum infection rates for TBEV of Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis were 0.06%, 0.17%, and 2.38%, respectively. Phylogenetic analysis based on the partial E protein gene was performed to identify relationships between the TBEV strains. This showed that 10 Korean strains clustered with the Western subtype. In this study, we investigated the prevalence of tick-borne encephalitis virus (TBEV) in ixodid ticks from various regions of the Republic of Korea (ROK) during 2011-2012 to identify whether TBEV is circulating and to determine the endemic regions of TBEV.

Scouts, forests, and ticks: Impact of landscapes on human-tick contacts.

PubMed

De Keukeleire, Mathilde; Vanwambeke, Sophie O; Somassè, Elysée; Kabamba, Benoît; Luyasu, Victor; Robert, Annie

2015-07-01

Just as with forest workers or people practicing outdoor recreational activities, scouts are at high risk for tick bites and tick-borne infections. The risk of a tick bite is shaped not only by environmental and climatic factors but also by land management. The aim of this study was to assess which environmental conditions favour scout-tick contacts, and thus to better understand how these factors and their interactions influence the two components of risk: hazard (related to vector and host ecology) and exposure of humans to disease vectors. A survey was conducted in the summer of 2009 on the incidence of tick bites in scout camps taking place in southern Belgium. Joint effects of landscape composition and configuration, weather, climate, forest and wildlife management were examined using a multiple gamma regression with a log link. The landscape was characterized by buffers of varying sizes around the camps using a detailed land use map, and accounting for climate and weather variables. Landscape composition and configuration had a significant influence on scout-tick contacts: the risk was high when the camp was surrounded by a low proportion of arable land and situated in a complex and fragmented landscape. The distance to the nearest forest patch, the composition of the forest ecotone as well as weather and climatic factors were all significantly associated with scout-tick contacts. Both hazard- and exposure-related variables significantly contributed to the frequency of scout-tick contact. Our results show that environmental conditions favour scout-tick contacts. For example, we emphasize the impact of accessibility of environments suitable for ticks on the risk of contact. We also highlight the significant effect of both hazard and exposure. Our results are consistent with current knowledge, but further investigations on the effect of forest management, e.g. through its impact on forest structure, on the tick-host-pathogen system, and on humans exposure, is required. Copyright © 2015 Elsevier GmbH. All rights reserved.

Systems Biology of Tissue-Specific Response to Anaplasma phagocytophilum Reveals Differentiated Apoptosis in the Tick Vector Ixodes scapularis

PubMed Central

Ayllón, Nieves; Villar, Margarita; Galindo, Ruth C.; Kocan, Katherine M.; Šíma, Radek; López, Juan A.; Vázquez, Jesús; Alberdi, Pilar; Cabezas-Cruz, Alejandro; Kopáček, Petr; de la Fuente, José

2015-01-01

Anaplasma phagocytophilum is an emerging pathogen that causes human granulocytic anaplasmosis. Infection with this zoonotic pathogen affects cell function in both vertebrate host and the tick vector, Ixodes scapularis. Global tissue-specific response and apoptosis signaling pathways were characterized in I. scapularis nymphs and adult female midguts and salivary glands infected with A. phagocytophilum using a systems biology approach combining transcriptomics and proteomics. Apoptosis was selected for pathway-focused analysis due to its role in bacterial infection of tick cells. The results showed tissue-specific differences in tick response to infection and revealed differentiated regulation of apoptosis pathways. The impact of bacterial infection was more pronounced in tick nymphs and midguts than in salivary glands, probably reflecting bacterial developmental cycle. All apoptosis pathways described in other organisms were identified in I. scapularis, except for the absence of the Perforin ortholog. Functional characterization using RNA interference showed that Porin knockdown significantly increases tick colonization by A. phagocytophilum. Infection with A. phagocytophilum produced complex tissue-specific alterations in transcript and protein levels. In tick nymphs, the results suggested a possible effect of bacterial infection on the inhibition of tick immune response. In tick midguts, the results suggested that A. phagocytophilum infection inhibited cell apoptosis to facilitate and establish infection through up-regulation of the JAK/STAT pathway. Bacterial infection inhibited the intrinsic apoptosis pathway in tick salivary glands by down-regulating Porin expression that resulted in the inhibition of Cytochrome c release as the anti-apoptotic mechanism to facilitate bacterial infection. However, tick salivary glands may promote apoptosis to limit bacterial infection through induction of the extrinsic apoptosis pathway. These dynamic changes in response to A. phagocytophilum in I. scapularis tissue-specific transcriptome and proteome demonstrated the complexity of the tick response to infection and will contribute to characterize gene regulation in ticks. PMID:25815810

Future challenges for parasitology: vector control and 'One health' in Europe: the veterinary medicinal view on CVBDs such as tick borreliosis, rickettsiosis and canine leishmaniosis.

PubMed

Mencke, Norbert

2013-08-01

The medical as well as the veterinary importance of parasitic arthropods or ectoparasites in general terms, is characterized by the primary or secondary impact on the health of humans and companion animals alike. The parasitic arthropods addressed here are those ectoparasites belong to the class of insects, such as fleas and sand flies, or the subclass of acarids, such as ticks. These parasitic arthropods interact intensively with their hosts by blood feeding. Fleas, sand flies and ticks hold the vector capacity to transmit pathogens such as virus, bacteria or protozoa to cats, dogs and humans. The diseases caused by these pathogens are summarized under the terms canine vector-borne diseases (CVBD), feline vector-borne diseases (FVBD) or metazoonoses. In small animal practice, it is important to understand that the transmitted pathogen may either lead to a disease with clinical signs, or more often to asymptomatic, clinically healthy, or silent infections. Blocking of the vector-host interactions, the blood feeding and subsequently the transmission of pathogens during blood feeding is a key element of CVBD control. The focus of this review is on the current knowledge of the epidemiology of parasitic vectors and three important CVBDs they transmit; rickettsiosis, tick borreliosis and canine leishmaniosis from a European perspective, and how veterinary medicine may contribute to the challenges of CVBDs and their control. Prevention of CVBDs is fundamentally based on ectoparasite control. Ectoparasite management in cats and dogs is important not only for the health and well-being of the individual companion animal but for public health in general and is therefore a perfect example of the 'One health' approach. Copyright © 2013. Published by Elsevier B.V.

Borrelia burgdorferi in small mammal reservoirs in Kentucky, a traditionally non-endemic state for Lyme disease.

PubMed

Buchholz, Matthew J; Davis, Cheryl; Rowland, Naomi S; Dick, Carl W

2018-04-01

The incidence of tick-borne zoonoses such as Lyme disease has steadily increased in the southeastern United States. Southeastern states accounted for 1500 of over 28,000 confirmed cases of Lyme disease reported in the United States during 2015. Borrelia burgdorferi, the etiologic agent of Lyme disease, is maintained in small mammal reservoirs and vectored to new hosts by ixodid ticks. This study examined ecological relationships of the B. burgdorferi/vector/reservoir system in order to understand the dynamics of Lyme disease risk in Kentucky. Small mammals were captured using live traps from November 2014 to October 2015. Ticks were removed and blood and tissue collected from small mammals were screened for B. burgdorferi DNA by PCR with primers specific to the OspA gene. Prevalence of B. burgdorferi (21.8%) in Kentucky small mammals was comparable to the lowest recorded prevalence in regions where Lyme disease is endemic. Moreover, infestation of small mammals by Ixodes scapularis, the primary vector of B. burgdorferi, was rare, while Dermacentor variabilis comprised the majority of ticks collected. These findings provide ecological insight into the relative paucity of Lyme disease in Kentucky.

Molecular Detection of Rickettsia africae in Amblyomma variegatum Collected from Sudan.

PubMed

Nakao, Ryo; Qiu, Yongjin; Salim, Bashir; Hassan, Shawgi Mohamed; Sugimoto, Chihiro

2015-05-01

Despite the increasing awareness of the importance of emerging vector-borne diseases, human tick-borne diseases, particularly rickettsial infections, are overlooked, especially in the countries such as Sudan with limited resources to perform molecular-based surveys. This study aimed at detection and genetic characterization of Rickettsia spp. in ticks collected from Sudan. The samples were first screened for the presence of rickettsial agents by gltA real-time PCR and subsequently characterized by gltA and ompA PCR and size-based multispacer typing. The results demonstrated the wide distribution of Rickettsia africae and/or closely related species across Sudan. The results of this report highlight the need for careful consideration of rickettsial infections in patients with nonmalarial febrile illness in this country. Nationwide surveillance on ticks associated with human rickettsial infections in Sudan is warranted.

Whole genome phylogenetic investigation of a West Nile virus strain isolated from a tick sampled from livestock in north eastern Kenya.

PubMed

Lwande, Olivia Wesula; Venter, Marietjie; Lutomiah, Joel; Michuki, George; Rumberia, Cecilia; Gakuya, Francis; Obanda, Vincent; Tigoi, Caroline; Odhiambo, Collins; Nindo, Fredrick; Symekher, Samwel; Sang, Rosemary

2014-11-28

West Nile virus (WNV) has a wide geographical distribution and has been associated to cause neurological disease in humans and horses. Mosquitoes are the traditional vectors for WNV; however, the virus has also been isolated from tick species in North Africa and Europe which could be a means of introduction and spread of the virus over long distances through migratory birds. Although WNV has been isolated in mosquitoes in Kenya, paucity of genetic and pathogenicity data exists. We previously reported the isolation of WNV from ticks collected from livestock and wildlife in Ijara District of Kenya, a hotspot for arbovirus activity. Here we report the full genome sequence and phylogenetic investigation of their origin and relation to strains from other regions. A total of 10,488 ticks were sampled from animal hosts, classified to species and processed in pools of up to eight ticks per pool. Virus screening was performed by cell culture, RT-PCR and sequencing. Phylogenetic analysis was carried out to determine the evolutionary relationships of our isolate. Among other viruses, WNV was isolated from a pool of Rhipicephalus pulchellus sampled from cattle, sequenced and submitted to GenBank (Accession number: KC243146). Comparative analysis with 27 different strains revealed that our isolate belongs to lineage 1 and clustered relatively closely to isolates from North Africa and Europe, Russia and the United States. Overall, Bayesian analysis based on nucleotide sequences showed that lineage 1 strains including the Kenyan strain had diverged 200 years ago from lineage 2 strains of southern Africa. Ijara strain collected from a tick sampled on livestock was closest to another Kenyan strain and had diverged 20 years ago from strains detected in Morocco and Europe and 30 years ago from strains identified in the USA. To our knowledge, this is the first characterized WNV strain isolated from R. pulchellus. The epidemiological role of this tick in WNV transmission and dissemination remains equivocal but presents tick verses mosquito virus transmission has been neglected. Genetic data of this strain suggest that lineage 1 strains from Africa could be dispersed through tick vectors by wild migratory birds to Europe and beyond.

Anaplasma phagocytophilum in questing Ixodes ricinus ticks from Romania.

PubMed

Matei, Ioana Adriana; Kalmár, Zsuzsa; Magdaş, Cristian; Magdaş, Virginia; Toriay, Hortenzia; Dumitrache, Mirabela Oana; Ionică, Angela Monica; D'Amico, Gianluca; Sándor, Attila D; Mărcuţan, Daniel Ioan; Domşa, Cristian; Gherman, Călin Mircea; Mihalca, Andrei Daniel

2015-04-01

Granulocytic anaplasmosis is a common vector-borne disease of humans and animals with natural transmission cycle that involves tick vectors, among which Ixodes ricinus is the most important. The present paper reports the prevalence and geographical distribution of A. phagocytophilum in 10,438 questing Ixodes ricinus ticks collected at 113 locations from 40 counties of Romania. The unfed ticks were examined for the presence of A. phagocytophilum by PCR targeting a portion of ankA gene. The overall prevalence of infection was 3.42%, with local prevalences ranging between 0.29% and 22.45%, with an average prevalence of 5.39% in the infected localities. The infection with A. phagocytophilum was detected in 72 out of 113 localities and in 34 out of 40 counties. The highest prevalence was recorded in females followed by males and nymphs. The results and the distribution model have shown a large distribution of A. phagocytophilum, covering Romania's entire territory. This study is the first large scale survey of the presence of A. phagocytophilum in questing I. ricinus ticks from Romania. Copyright © 2015 Elsevier GmbH. All rights reserved.

Invasion of two tick-borne diseases across New England: harnessing human surveillance data to capture underlying ecological invasion processes

PubMed Central

Walter, Katharine S.; Pepin, Kim M.; Webb, Colleen T.; Gaff, Holly D.; Krause, Peter J.; Pitzer, Virginia E.; Diuk-Wasser, Maria A.

2016-01-01

Modelling the spatial spread of vector-borne zoonotic pathogens maintained in enzootic transmission cycles remains a major challenge. The best available spatio-temporal data on pathogen spread often take the form of human disease surveillance data. By applying a classic ecological approach—occupancy modelling—to an epidemiological question of disease spread, we used surveillance data to examine the latent ecological invasion of tick-borne pathogens. Over the last half-century, previously undescribed tick-borne pathogens including the agents of Lyme disease and human babesiosis have rapidly spread across the northeast United States. Despite their epidemiological importance, the mechanisms of tick-borne pathogen invasion and drivers underlying the distinct invasion trajectories of the co-vectored pathogens remain unresolved. Our approach allowed us to estimate the unobserved ecological processes underlying pathogen spread while accounting for imperfect detection of human cases. Our model predicts that tick-borne diseases spread in a diffusion-like manner with occasional long-distance dispersal and that babesiosis spread exhibits strong dependence on Lyme disease. PMID:27252022

Ticks and tick-borne diseases in Oklahoma.

PubMed

Moody, E K; Barker, R W; White, J L; Crutcher, J M

1998-11-01

Tick-borne diseases are common in Oklahoma, especially the eastern part of the state where tick prevalence is highest. Three species of hard ticks are present in Oklahoma that are known vectors of human disease--the American dog tick (Rocky Mountain spotted fever; RMSF), the lone star tick (ehrlichiosis) and the black-legged tick (Lyme disease). Oklahoma consistently ranks among the top states in numbers of reported RMSF cases, and Ehrlichiosis may be as prevalent as RMSF. Although Lyme disease is frequently reported in Oklahoma, over-diagnosing of this disease due to false-positive test results is common; positive or equivocal screening tests should be confirmed by Western immunoblot. At present, it is unclear whether the disease seen here is Lyme disease or another Lyme-like disease. If true Lyme disease is present in the state, it is probably rare. Physicians should be aware of the most recent recommendations for diagnosis, therapy and prevention of tick-borne diseases.

Bioinformatic prediction of G protein-coupled receptor encoding sequences from the transcriptome of the foreleg, including the Haller’s organ, of the cattle tick, Rhipicephalus australis

USDA-ARS?s Scientific Manuscript database

The cattle tick of Australia, Rhipicephalus australis, is a vector for microbial parasites that cause serious bovine diseases. The Haller's organ, located in the tick's forelegs, is crucial for host detection and mating. To facilitate the development of new technologies for better control of this ag...

Development and validation of a dual luciferase reporter system for in vitro evaluation of gene silencing efficacy in the Southern cattle tick: comparison to in vivo gene silencing by microinjection

USDA-ARS?s Scientific Manuscript database

The Southern cattle tick, Rhipicephalus (Boophilus) microplus, vectors bovine babesiosis and anaplasmosis, and was eradicated from the United States over several decades by the Cattle Fever Tick Eradication Program (CFTEP); however, R. microplus is endemic in Mexico and remains a continuing threat t...

Molecular and pharmacological characterization of the Chelicerata pyrokinin receptor from the southern cattle tick, Rhipicephalus (Boophilus) microplus.

PubMed

Yang, Yunlong; Nachman, Ronald J; Pietrantonio, Patricia V

2015-05-01

We identified the first pyrokinin receptor (Rhimi-PKR) in Chelicerata and analyzed structure-activity relationships of cognate ligand neuropeptides and their analogs. Based on comparative and phylogenetic analyses, this receptor, which we cloned from larvae of the cattle tick Rhipicephalus microplus (Acari: Ixodidae), is the ortholog of the insect pyrokinin (PK)/pheromone biosynthesis activating neuropeptide (PBAN)/diapause hormone (DH) neuropeptide family receptor. Rhimi-PKR functional analyses using calcium bioluminescence were performed with a developed stable recombinant CHO-K1 cell line. Rhimi-PKR was activated by four endogenous PKs from the Lyme disease vector, the tick Ixodes scapularis (EC50s range: 85.4 nM-546 nM), and weakly by another tick PRX-amide peptide, periviscerokinin (PVK) (EC50 = 24.5 μM). PK analogs with substitutions of leucine, isoleucine or valine at the C-terminus for three tick PK peptides, Ixosc-PK1, Ixosc-PK2, and Ixosc-PK3, retained their potency on Rhimi-PKR. Therefore, Rhimi-PKR is less selective and substantially more tolerant than insect PK receptors of C-terminal substitutions of leucine to isoleucine or valine, a key structural feature that serves to distinguish insect PK from PVK/CAP2b receptors. In females, ovary and synganglion had the highest Rhimi-PKR relative transcript abundance followed by the rectal sac, salivary glands, Malpighian tubules, and midgut. This is the first pharmacological analysis of a PK/PBAN/DH-like receptor from the Chelicerata, which will now permit the discovery of the endocrinological roles of this neuropeptide family in vectors of vertebrate pathogens. Copyright © 2015 Elsevier Ltd. All rights reserved.

Regulatory protein BBD18 of the lyme disease spirochete: essential role during tick acquisition?

PubMed

Hayes, Beth M; Dulebohn, Daniel P; Sarkar, Amit; Tilly, Kit; Bestor, Aaron; Ambroggio, Xavier; Rosa, Patricia A

2014-04-01

The Lyme disease spirochete Borrelia burgdorferi senses and responds to environmental cues as it transits between the tick vector and vertebrate host. Failure to properly adapt can block transmission of the spirochete and persistence in either vector or host. We previously identified BBD18, a novel plasmid-encoded protein of B. burgdorferi, as a putative repressor of the host-essential factor OspC. In this study, we investigate the in vivo role of BBD18 as a regulatory protein, using an experimental mouse-tick model system that closely resembles the natural infectious cycle of B. burgdorferi. We show that spirochetes that have been engineered to constitutively produce BBD18 can colonize and persist in ticks but do not infect mice when introduced by either tick bite or needle inoculation. Conversely, spirochetes lacking BBD18 can persistently infect mice but are not acquired by feeding ticks. Through site-directed mutagenesis, we have demonstrated that abrogation of spirochete infection in mice by overexpression of BBD18 occurs only with bbd18 alleles that can suppress OspC synthesis. Finally, we demonstrate that BBD18-mediated regulation does not utilize a previously described ospC operator sequence required by B. burgdorferi for persistence in immunocompetent mice. These data lead us to conclude that BBD18 does not represent the putative repressor utilized by B. burgdorferi for the specific downregulation of OspC in the mammalian host. Rather, we suggest that BBD18 exhibits features more consistent with those of a global regulatory protein whose critical role occurs during spirochete acquisition by feeding ticks. IMPORTANCE Lyme disease, caused by Borrelia burgdorferi, is the most common arthropod-borne disease in North America. B. burgdorferi is transmitted to humans and other vertebrate hosts by ticks as they take a blood meal. Transmission between vectors and hosts requires the bacterium to sense changes in the environment and adapt. However, the mechanisms involved in this process are not well understood. By determining how B. burgdorferi cycles between two very different environments, we can potentially establish novel ways to interfere with transmission and limit infection of this vector-borne pathogen. We are studying a regulatory protein called BBD18 that we recently described. We found that too much BBD18 interferes with the spirochete's ability to establish infection in mice, whereas too little BBD18 appears to prevent colonization in ticks. Our study provides new insight into key elements of the infectious cycle of the Lyme disease spirochete.

Novel Rickettsia raoultii strain isolated and propagated from Austrian Dermacentor reticulatus ticks.

PubMed

Wijnveld, Michiel; Schötta, Anna-Margarita; Pintér, Adriano; Stockinger, Hannes; Stanek, Gerold

2016-11-03

Continuous culture of tick cell lines has proven a valuable asset in isolating and propagating several different vector-borne pathogens, making it possible to study these microorganisms under laboratory conditions and develop serological tests to benefit public health. We describe a method for effective, cost- and labor-efficient isolation and propagation of Rickettsia raoultii using generally available laboratory equipment and Rhipicephalus microplus cells, further demonstrating the usefulness of continuous tick cell lines. R. raoultii is one of the causative agents of tick-borne lymphadenopathy (TIBOLA) and is, together with its vector Dermacentor reticulatus, emerging in novel regions of Europe, giving rise to an increased threat to general public health. Dermacentor reticulatus ticks were collected in the Donau-Auen (Lobau) national park in Vienna, Austria. The hemolymph of ten collected ticks was screened by PCR-reverse line blot for the presence of rickettsial DNA. A single tick tested positive for R. raoultii DNA and was used to infect Rhipicephalus microplus BME/CTVM2 cells. Sixty-five days after infection of the tick-cell line with an extract from a R. raoultii-infected tick, we observed intracellular bacteria in the cultured cells. On the basis of microscopy we suspected that the intracellular bacteria were a species of Rickettsia; this was confirmed by several PCRs targeting different genes. Subsequent sequencing showed 99-100 % identity with R. raoultii. Cryopreservation and resuscitation of R. raoultii was successful. After 28 days identical intracellular bacteria were microscopically observed. R. raoultii was successfully isolated and propagated from D. reticulatus ticks using R. microplus BME/CTVM2 cells. The isolated strain shows significant molecular variation compared to currently known sequences. Furthermore we show for the first time the successful cryopreservation and resuscitation of R. raoultii.

Tick-borne diseases in North Carolina: is "Rickettsia amblyommii" a possible cause of rickettsiosis reported as Rocky Mountain spotted fever?

PubMed

Apperson, Charles S; Engber, Barry; Nicholson, William L; Mead, Daniel G; Engel, Jeffrey; Yabsley, Michael J; Dail, Kathy; Johnson, Joey; Watson, D Wesley

2008-10-01

Cases of Rocky Mountain spotted fever (RMSF) in North Carolina have escalated markedly since 2000. In 2005, we identified a county in the Piedmont region with high case numbers of RMSF. We collected ticks and examined them for bacterial pathogens using molecular methods to determine if a novel tick vector or spotted fever group rickettsiae (SFGR) might be emerging. Amblyomma americanum, the lone star tick, comprised 99.6% of 6,502 specimens collected in suburban landscapes. In contrast, Dermacentor variabilis, the American dog tick, a principal vector of Rickettsia rickettsii, comprised < 1% of the ticks collected. Eleven of 25 lone star tick pools tested were infected with "Rickettsia amblyommii," an informally named SFGR. Sera from patients from the same county who were presumptively diagnosed by local physicians with a tick-borne illness were tested by an indirect immunofluorescence antibody (IFA) assay to confirm clinical diagnoses. Three of six patients classified as probable RMSF cases demonstrated a fourfold or greater rise in IgG class antibody titers between paired acute and convalescent sera to "R. amblyommii" antigens, but not to R. rickettsii antigens. White-tailed deer, Odocoileus virginianus, are preferred hosts of lone star ticks. Blood samples collected from hunter-killed deer from the same county were tested by IFA test for antibodies to Ehrlichia chaffeensis and "R. amblyommii." Twenty-eight (87%) of 32 deer were positive for antibodies to E. chaffeensis, but only 1 (3%) of the deer exhibited antibodies to "R. amblyommii," suggesting that deer are not the source of "R. amblyommii" infection for lone star ticks. We propose that some cases of rickettsiosis reported as RMSF may have been caused by "R. amblyommii" transmitted through the bite of A. americanum.

Species distribution and detection of Crimean Congo Hemorrhagic Fever Virus (CCHFV) in field-collected ticks in Ankara Province, Central Anatolia, Turkey.

PubMed

Hekimoglu, Olcay; Ozer, Nurdan; Ergunay, Koray; Ozkul, Aykut

2012-01-01

Ticks may act as vectors for a number of infectious diseases including Crimean Congo Hemorrhagic Fever (CCHF). The causative agent is Crimean Congo Hemorrhagic Fever Virus (CCHFV), a member of Bunyaviridae, causing extensive ecchymosis, visceral bleeding and hepatic dysfunction with a high fatality rate in the affected individuals. CCHF was initially recognized in Turkey in 2002 and the current number of reported cases exceeds 4,400. This study was conducted to confirm the presence of tick species established as potential CCHFV vectors and investigate CCHFV activity in ticks at Ankara province, Turkey's second most-densely populated province, where CCHF cases were demonstrated. A total of 1,196 adult ticks, collected from various animals and vegetation in 12 sites located in 5 counties of Ankara during April-July 2010 were identified to species level. Twenty-two tick pools from county K2 were also evaluated for the presence of CCHFV RNA via a one-step real-time RT-PCR assay and reactive results were further confirmed by an in house nested RT-PCR assay. Nine tick species were identified: Rhipicephalus bursa (44.9%), R. sanguineus (18.9%), R. turanicus (18.1%), Haemaphysalis parva (8.3%), Hyalomma marginatum marginatum (5.4%), H. aegyptium (1.4%), H. anatolicum excavatum (1.3%), Hae. punctata (0.3%) and Dermacentor marginatus (0.2%). A total of five tick pools (22.7%) were reactive in real-time and nested RT-PCR assays. The pools included R. bursa, H. m. marginatum and Hae. parva ticks, collected from mammal hosts from two villages in one county. This is the first documentation of CCHFV activity in ticks from Ankara province, which indicates requirement for detailed surveillance to predict high risk zones in the region.

Linkages of Weather and Climate With Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae), Enzootic Transmission of Borrelia burgdorferi, and Lyme Disease in North America.

PubMed

Eisen, Rebecca J; Eisen, Lars; Ogden, Nicholas H; Beard, Charles B

2016-03-01

Lyme disease has increased both in incidence and geographic extent in the United States and Canada over the past two decades. One of the underlying causes is changes during the same time period in the distribution and abundance of the primary vectors: Ixodes scapularis Say and Ixodes pacificus Cooley and Kohls in eastern and western North America, respectively. Aside from short periods of time when they are feeding on hosts, these ticks exist in the environment where temperature and relative humidity directly affect their development, survival, and host-seeking behavior. Other important factors that strongly influence tick abundance as well as the proportion of ticks infected with the Lyme disease spirochete, Borrelia burgdorferi, include the abundance of hosts for the ticks and the capacity of tick hosts to serve as B. burgdorferi reservoirs. Here, we explore the linkages between climate variation and: 1) duration of the seasonal period and the timing of peak activity; 2) geographic tick distributions and local abundance; 3) enzootic B. burgdorferi transmission cycles; and 4) Lyme disease cases. We conclude that meteorological variables are most influential in determining host-seeking phenology and development, but, while remaining important cofactors, additional variables become critical when exploring geographic distribution and local abundance of ticks, enzootic transmission of B. burgdorferi, and Lyme disease case occurrence. Finally, we review climate change-driven projections for future impact on vector ticks and Lyme disease and discuss knowledge gaps and research needs.

Importance of ticks and their chemical and immunological control in livestock*

PubMed Central

Rajput, Zahid Iqbal; Hu, Song-hua; Chen, Wan-jun; Arijo, Abdullah G.; Xiao, Chen-wen

2006-01-01

The medical and economic importance of ticks has long been recognized due to their ability to transmit diseases to humans and animals. Ticks cause great economic losses to livestock, and adversely affect livestock hosts in several ways. Loss of blood is a direct effect of ticks acting as potential vector for haemo-protozoa and helminth parasites. Blood sucking by large numbers of ticks causes reduction in live weight and anemia among domestic animals, while their bites also reduce the quality of hides. However, major losses caused by ticks are due to their ability to transmit protozoan, rickettsial and viral diseases of livestock, which are of great economic importance world-wide. There are quite a few methods for controlling ticks, but every method has certain shortcomings. The present review is focused on ticks importance and their control. PMID:17048307

Climate change influences on the potential geographic distribution of the disease vector tick Ixodes ricinus

PubMed Central

Peterson, A. Townsend; Samy, Abdallah M.

2017-01-01

Background Ixodes ricinus is a species of hard tick that transmits several important diseases in Europe and North Africa, including Lyme borreliosis and tick-borne encephalitis. Climate change is affecting the geographic distributions and abundances of arthropod vectors, which in turn influence the geographic distribution and epidemiology of associated vector-borne diseases. To date, few studies have investigated effects of climate change on the spatial distribution of I. ricinus at continental extents. Here, we assessed the potential distribution of I. ricinus under current and future climate conditions to understand how climate change will influence the geographic distribution of this important tick vector in coming decades. Method We used ecological niche modeling to estimate the geographic distribution of I. ricinus with respect to current climate, and then assessed its future potential distribution under different climate change scenarios. This approach integrates occurrence records of I. ricinus with six relevant environmental variables over a continental extent that includes Europe, North Africa, and the Middle East. Future projections were based on climate data from 17 general circulation models (GCMs) under 2 representative concentration pathway emissions scenarios (RCPs), for the years 2050 and 2070. Result The present and future potential distributions of I. ricinus showed broad overlap across most of western and central Europe, and in more narrow zones in eastern and northern Europe, and North Africa. Potential expansions were observed in northern and eastern Europe. These results indicate that I. ricinus populations could emerge in areas in which they are currently lacking, posing increased risks to human health in those areas. However, the future of I. ricinus ticks in some important regions such the Mediterranean was unclear owing to high uncertainty in model predictions. PMID:29206879

Climate change influences on the potential geographic distribution of the disease vector tick Ixodes ricinus.

PubMed

Alkishe, Abdelghafar A; Peterson, A Townsend; Samy, Abdallah M

2017-01-01

Ixodes ricinus is a species of hard tick that transmits several important diseases in Europe and North Africa, including Lyme borreliosis and tick-borne encephalitis. Climate change is affecting the geographic distributions and abundances of arthropod vectors, which in turn influence the geographic distribution and epidemiology of associated vector-borne diseases. To date, few studies have investigated effects of climate change on the spatial distribution of I. ricinus at continental extents. Here, we assessed the potential distribution of I. ricinus under current and future climate conditions to understand how climate change will influence the geographic distribution of this important tick vector in coming decades. We used ecological niche modeling to estimate the geographic distribution of I. ricinus with respect to current climate, and then assessed its future potential distribution under different climate change scenarios. This approach integrates occurrence records of I. ricinus with six relevant environmental variables over a continental extent that includes Europe, North Africa, and the Middle East. Future projections were based on climate data from 17 general circulation models (GCMs) under 2 representative concentration pathway emissions scenarios (RCPs), for the years 2050 and 2070. The present and future potential distributions of I. ricinus showed broad overlap across most of western and central Europe, and in more narrow zones in eastern and northern Europe, and North Africa. Potential expansions were observed in northern and eastern Europe. These results indicate that I. ricinus populations could emerge in areas in which they are currently lacking, posing increased risks to human health in those areas. However, the future of I. ricinus ticks in some important regions such the Mediterranean was unclear owing to high uncertainty in model predictions.

Widespread dispersal of Borrelia burgdorferi-infected ticks collected from songbirds across Canada.

PubMed

Scott, John D; Anderson, John F; Durden, Lance A

2012-02-01

Millions of Lyme disease vector ticks are dispersed annually by songbirds across Canada, but often overlooked as the source of infection. For clarity on vector distribution, we sampled 481 ticks (12 species and 3 undetermined ticks) from 211 songbirds (42 species/subspecies) nationwide. Using PCR, 52 (29.5%) of 176 Ixodes ticks tested were positive for the Lyme disease spirochete, Borrelia burgdorferi s.l. Immature blacklegged ticks, Ixodes scapularis , collected from infested songbirds had a B. burgdorferi infection prevalence of 36% (larvae, 48%; nymphs, 31%). Notably, Ixodes affinis is reported in Canada for the first time and, similarly, Ixodes auritulus for the initial time in the Yukon. Firsts for bird-parasitizing ticks include I. scapularis in Quebec and Saskatchewan. We provide the first records of 3 tick species cofeeding on passerines (song sparrow, Swainson's thrush). New host records reveal I. scapularis on the blackpoll warbler and Nashville warbler. We furnish the following first Canadian reports of B. burgdorferi-positive ticks: I. scapularis on chipping sparrow, house wren, indigo bunting; I. auritulus on Bewick's wren; and I. spinipalpis on a Bewick's wren and song sparrow. First records of B. burgdorferi-infected ticks on songbirds include the following: the rabbit-associated tick, Ixodes dentatus, in western Canada; I. scapularis in Quebec, Saskatchewan, northern New Brunswick, northern Ontario; and Ixodes spinipalpis (collected in British Columbia). The presence of B. burgdorferi in Ixodes larvae suggests reservoir competency in 9 passerines (Bewick's wren, common yellowthroat, dark-eyed junco, Oregon junco, red-winged blackbird, song sparrow, Swainson's thrush, swamp sparrow, and white-throated sparrow). We report transstadial transmission (larva to nymph) of B. burgdorferi in I. auritulus. Data suggest a possible 4-tick, i.e., I. angustus, I. auritulus, I. pacificus, and I. spinipalpis, enzootic cycle of B. burgdorferi on Vancouver Island, British Columbia. Our results suggest that songbirds infested with B. burgdorferi-infected ticks have the potential to start new tick populations endemic for Lyme disease. Because songbirds disperse B. burgdorferi-infected ticks outside their anticipated range, health-care providers are advised that people can contract Lyme disease locally without any history of travel.

Changing geographic ranges of ticks and tick-borne pathogens: drivers, mechanisms and consequences for pathogen diversity

PubMed Central

Ogden, Nick H.; Mechai, Samir; Margos, Gabriele

2013-01-01

The geographic ranges of ticks and tick-borne pathogens are changing due to global and local environmental (including climatic) changes. In this review we explore current knowledge of the drivers for changes in the ranges of ticks and tick-borne pathogen species and strains via effects on their basic reproduction number (R0), and the mechanisms of dispersal that allow ticks and tick-borne pathogens to invade suitable environments. Using the expanding geographic distribution of the vectors and agent of Lyme disease as an example we then investigate what could be expected of the diversity of tick-borne pathogens during the process of range expansion, and compare this with what is currently being observed. Lastly we explore how historic population and range expansions and contractions could be reflected in the phylogeography of ticks and tick-borne pathogens seen in recent years, and conclude that combined study of currently changing tick and tick-borne pathogen ranges and diversity, with phylogeographic analysis, may help us better predict future patterns of invasion and diversity. PMID:24010124

Changing geographic ranges of ticks and tick-borne pathogens: drivers, mechanisms and consequences for pathogen diversity.

PubMed

Ogden, Nick H; Mechai, Samir; Margos, Gabriele

2013-01-01

The geographic ranges of ticks and tick-borne pathogens are changing due to global and local environmental (including climatic) changes. In this review we explore current knowledge of the drivers for changes in the ranges of ticks and tick-borne pathogen species and strains via effects on their basic reproduction number (R 0), and the mechanisms of dispersal that allow ticks and tick-borne pathogens to invade suitable environments. Using the expanding geographic distribution of the vectors and agent of Lyme disease as an example we then investigate what could be expected of the diversity of tick-borne pathogens during the process of range expansion, and compare this with what is currently being observed. Lastly we explore how historic population and range expansions and contractions could be reflected in the phylogeography of ticks and tick-borne pathogens seen in recent years, and conclude that combined study of currently changing tick and tick-borne pathogen ranges and diversity, with phylogeographic analysis, may help us better predict future patterns of invasion and diversity.

Comparative evaluation of Amblyomma ovale ticks infected and noninfected by Rickettsia sp. strain Atlantic rainforest, the agent of an emerging rickettsiosis in Brazil.

PubMed

Krawczak, Felipe S; Agostinho, Washington C; Polo, Gina; Moraes-Filho, Jonas; Labruna, Marcelo B

2016-04-01

In 2010, a novel spotted fever group rickettsiosis was reported in the Atlantic rainforest coast of Brazil. The etiological agent was identified as Rickettsia sp. strain Atlantic rainforest, and the tick Amblyomma ovale was incriminated as the presumed vector. The present study evaluated under laboratory conditions four colonies of A. ovale: two started from engorged females that were naturally infected by Rickettsia sp. strain Atlantic rainforest (designated as infected groups); the two others started from noninfected females (designated as control groups). All colonies were reared in parallel from F0 engorged female to F2 unfed nymphs. Tick-naïve vesper mice (Calomys callosus) or domestic rabbits were used for feeding of each tick stage. Rickettsia sp. strain Atlantic rainforest was preserved by transstadial maintenance and transovarial transmission in A. ovale ticks for at least 2 generations (from F0 females to F2 nymphs), because nearly 100% of the tested larvae, nymphs, and adults from the infected groups were shown by PCR to contain rickettsial DNA. All vesper mice and rabbits infested by larvae and nymphs, and 50% of the rabbits infested by adults from the infected groups seroconverted, indicating that these tick stages were vector competent for Rickettsia sp. strain Atlantic rainforest. Expressive differences in mortality rates and reproductive performance were observed between engorged females from the infected and control groups, as indicated by 75.0% and 97.1% oviposition success, respectively, and significantly lower egg mass weight, conversion efficiency index, and percentage of egg hatching for the infected groups. Our results indicate that A. ovale can act as a natural reservoir for Rickettsia sp. strain Atlantic rainforest. However, due to deleterious effect caused by this rickettsial agent on engorged females, amplifier vertebrate hosts might be necessary for persistent perpetuation of Rickettsia sp. strain Atlantic rainforest in A. ovale under natural conditions. Copyright © 2016 Elsevier GmbH. All rights reserved.

Characterization of the bacterial communities of life stages of free living lone star ticks (Amblyomma americanum).

PubMed

Williams-Newkirk, Amanda Jo; Rowe, Lori A; Mixson-Hayden, Tonya R; Dasch, Gregory A

2014-01-01

The lone star tick (Amblyomma americanum) is an abundant and aggressive biter of humans, domestic animals, and wildlife in the southeastern-central USA and an important vector of several known and suspected zoonotic bacterial pathogens. However, the biological drivers of bacterial community variation in this tick are still poorly defined. Knowing the community context in which tick-borne bacterial pathogens exist and evolve is required to fully understand the ecology and immunobiology of the ticks and to design effective public health and veterinary interventions. We performed a metagenomic survey of the bacterial communities of questing A. americanum and tested 131 individuals (66 nymphs, 24 males, and 41 females) from five sites in three states. Pyrosequencing was performed with barcoded eubacterial primers targeting variable 16S rRNA gene regions 5-3. The bacterial communities were dominated by Rickettsia (likely R. amblyommii) and an obligate Coxiella symbiont, together accounting for 6.7-100% of sequences per tick. DNAs from Midichloria, Borrelia, Wolbachia, Ehrlichia, Pseudomonas, or unidentified Bacillales, Enterobacteriaceae, or Rhizobiales groups were also detected frequently. Wolbachia and Midichloria significantly co-occurred in Georgia (p<0.00001), but not in other states. The significance of the Midichloria-Wolbachia co-occurrence is unknown. Among ticks collected in Georgia, nymphs differed from adults in both the composition (p = 0.002) and structure (p = 0.002) of their bacterial communities. Adults differed only in their community structure (p = 0.002) with males containing more Rickettsia and females containing more Coxiella. Comparisons among adult ticks collected in New York and North Carolina supported the findings from the Georgia collection despite differences in geography, collection date, and sample handling, implying that the differences detected are consistent attributes. The data also suggest that some members of the bacterial community change during the tick life cycle and that some sex-specific attributes may be detectable in nymphs.

A tiny tick can cause a big health problem.

PubMed

John, Manuel; Raman, M; Ryan, Keith

2017-11-01

Ticks are tiny crawling bugs in the spider family that feed by sucking blood from animals. They are second only to mosquitoes as vectors of human disease, both infectious and toxic. Infected ticks spread over a hundred diseases, some of which are fatal if undetected. They spread the spirochete (which multiplies in the insect's gut) with a subsequent bite to the next host. We describe the only reported cases of peri ocular tick bite from India that presented to us within a span of 3 days and its management. Due suspicion and magnification of the lesions revealed the ticks which otherwise masqueraded as small skin tags/moles on gross examination. The ticks were firmly latched on to the skin and careful removal prevented incarceration of the mouth parts. Rickettsial diseases that were believed to have disappeared from India are reemerging and their presence has recently been documented in at least 11 states in the country. Among vector borne diseases, the most common, Lyme disease, also known as the great mimicker, can present with rheumatoid arthritis, fibromyalgia, depression, attention deficit hyperactivity disorder, multiple sclerosis, chronic fatigue syndrome, cardiac manifestations, encephalitis, and mental illness, to name some of the many associations. Common ocular symptoms and signs include conjunctivitis, keratitis, uveitis, and retinitis. Early detection and treatment of tick borne diseases is important to prevent multi system complications that can develop later in life.

Assessment of MALDI-TOF MS biotyping for Borrelia burgdorferi sl detection in Ixodes ricinus

PubMed Central

Boyer, Pierre H.; Boulanger, Nathalie; Nebbak, Amira; Collin, Elodie; Jaulhac, Benoit; Almeras, Lionel

2017-01-01

Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has been demonstrated to be useful for tick identification at the species level. More recently, this tool has been successfully applied for the detection of bacterial pathogens directly in tick vectors. The present work has assessed the detection of Borrelia burgdorferi sensu lato in Ixodes ricinus tick vector by MALDI-TOF MS. To this aim, experimental infection model of I. ricinus ticks by B. afzelii was carried out and specimens collected in the field were also included in the study. Borrelia infectious status of I. ricinus ticks was molecularly controlled using half-idiosome to classify specimens. Among the 39 ticks engorged on infected mice, 14 were confirmed to be infected by B. afzelii. For field collection, 14.8% (n = 12/81) I. ricinus ticks were validated molecularly as infected by B. burgdorferi sl. To determine the body part allowing the detection of MS protein profile changes between non-infected and B. afzelii infected specimens, ticks were dissected in three compartments (i.e. 4 legs, capitulum and half-idiosome) prior to MS analysis. Highly reproducible MS spectra were obtained for I. ricinus ticks according to the compartment tested and their infectious status. However, no MS profile change was found when paired body part comparison between non-infected and B. afzelii infected specimens was made. Statistical analyses did not succeed to discover, per body part, specific MS peaks distinguishing Borrelia-infected from non-infected ticks whatever their origins, laboratory reared or field collected. Despite the unsuccessful of MALDI-TOF MS to classify tick specimens according to their B. afzelii infectious status, this proteomic tool remains a promising method for rapid, economic and accurate identification of tick species. Moreover, the singularity of MS spectra between legs and half-idiosome of I. ricinus could be used to reinforce this proteomic identification by submission of both these compartments to MS. PMID:28950023

Tick parasites of rodents in Romania: host preferences, community structure and geographical distribution.

PubMed

Mihalca, Andrei D; Dumitrache, Mirabela O; Sándor, Attila D; Magdaş, Cristian; Oltean, Miruna; Györke, Adriana; Matei, Ioana A; Ionică, Angela; D'Amico, Gianluca; Cozma, Vasile; Gherman, Călin M

2012-11-21

Ticks are among the most important vectors of zoonotic diseases in temperate regions of Europe, with widespread distribution and high densities, posing an important medical risk. Most ticks feed on a variety of progressively larger hosts, with a large number of small mammal species typically harbouring primarily the immature stages. However, there are certain Ixodidae that characteristically attack micromammals also during their adult stage. Rodents are widespread hosts of ticks, important vectors and competent reservoirs of tick-borne pathogens. Micromammal-tick associations have been poorly studied in Romania, and our manuscript shows the results of a large scale study on tick infestation epidemiology in rodents from Romania. Rodents were caught using snap-traps in a variety of habitats in Romania, between May 2010 and November 2011. Ticks were individually collected from these rodents and identified to species and development stage. Frequency, mean intensity, prevalence and its 95% confidence intervals were calculated using the EpiInfo 2000 software. A p value of <0.05 was considered statistically significant. We examined 423 rodents (12 species) collected from six counties in Romania for the presence of ticks. Each collected tick was identified to species level and the following epidemiological parameters were calculated: prevalence, mean intensity and mean abundance. The total number of ticks collected from rodents was 483, with eight species identified: Ixodes ricinus, I. redikorzevi, I. apronophorus, I. trianguliceps, I. laguri, Dermacentor marginatus, Rhipicephalus sanguineus and Haemaphysalis sulcata. The overall prevalence of tick infestation was 29.55%, with a mean intensity of 3.86 and a mean abundance of 1.14. Only two polyspecific infestations were found: I. ricinus + I. redikorzevi and I. ricinus + D. marginatus. Our study showed a relatively high diversity of ticks parasitizing rodents in Romania. The most common tick in rodents was I. ricinus, followed by I. redikorzevi. Certain rodents seem to host a significantly higher number of tick species than others, the most important within this view being Apodemus flavicollis and Microtus arvalis. The same applies for the overall prevalence of tick parasitism, with some species more commonly infected (M. arvalis, A. uralensis, A. flavicollis and M. glareolus) than others. Two rodent species (Mus musculus, Rattus norvegicus) did not harbour ticks at all. Based on our results we may assert that rodents generally can act as good indicators for assessing the distribution of certain tick species.

Evaluation of the United States Department Of Agriculture Northeast Area-wide Tick Control Project by meta-analysis.

PubMed

Brei, Brandon; Brownstein, John S; George, John E; Pound, J Mathews; Miller, J Allen; Daniels, Thomas J; Falco, Richard C; Stafford, Kirby C; Schulze, Terry L; Mather, Thomas N; Carroll, John F; Fish, Durland

2009-08-01

As part of the Northeast Area-wide Tick Control Project (NEATCP), meta-analyses were performed using pooled data on the extent of tick-vector control achieved through seven concurrent studies, conducted within five states, using U.S. Department of Agriculture "4-Poster" devices to deliver targeted-acaricide to white-tailed deer. Although reductions in the abundance of all life-stages of Ixodes scapularis were the measured outcomes, this study focused on metrics associated with I. scapularis nymphal tick densities as this measure has consistently proven to directly correlate with human risk of acquiring Lyme disease. Since independent tick sampling schemes were undertaken at each of the five environmentally distinct study locations, a meta-analytic approach permitted estimation of a single true control-effect size for each treatment year of the NEATCP. The control-effect is expressed as the annual percent I. scapularis nymphal control most consistent with meta-analysis data for each treatment year. Our meta-analyses indicate that by the sixth treatment year, the NEATCP effectively reduced the relative density of I. scapularis nymphs by 71% on the 5.14 km(2) treatment sites, corresponding to a 71% lower relative entomologic risk index for acquiring Lyme disease.

Identification of tick-borne pathogen diversity by metagenomic analysis in Haemaphysalis longicornis from Xinyang, China.

PubMed

Zhuang, Lu; Du, Juan; Cui, Xiao-Ming; Li, Hao; Tang, Fang; Zhang, Pan-He; Hu, Jian-Gong; Tong, Yi-Gang; Feng, Zhi-Chun; Liu, Wei

2018-05-07

A wide variety of pathogens could be maintained and transmitted by Haemaphysalis longicornis. The aim of this study is to systematically examine the variety of pathogens carried by Haemaphysalis longicornis, an importnatn vector, in tick-borne diseases epidemic area, and to estimate the risk of human infection imposed by tick bites. Adult questing ticks were collected in Xinyang, central China. Genomic DNA and RNA were extracted from 144 H. longicornis ticks individually, and sequenced respectively as the templates for high-throughput sequencing. Clean reads were compared against the database of NCBI nucleotide collection and specific PCR was performed to confirm the presence of pathogen. Phylogenetic analysis was performed to explore the evolutionary status of pathogens. The assignment of reads to taxa based on BLASTN results revealed the existence of several potential pathogens, including Anaplasma spp., Rickettsia spp., Babesia sp., as well as severe fever with thrombocytopenia syndrome bunyavirus (SFTSV). Comfirmantory PCR assays revealed the existence of Anaplasma bovis (13/144, 9.03%), Anaplasma centrale (2/144, 1.39%), Rickettsia heilongjiangensis (3/144, 2.08%), Rickettsia sp. LON-13 (1/144, 0.69%), Rickettsia raoultii (5/144, 3.47%), Babesia sp. (1/144, 0.69%). SFTSV accounted for the highest detected pathogen with a positive rate of 18.75% (27/144). Three of the ticks (2.08%) were co-infected with SFTSV and A. bovis. Our study provided a broadened list of microorganism that harbored by H. longicornis. In previously unrecognized endemic regions, prokaryotic and eukaryotic infection including Anaplasma spp., Rickettsiae spp., and Babesia spp. should be considered, along with the well-known SFTSV for patients with tick bites history. A novel Babesia species was identified in local natural foci, which needs further investigation in the future.

Occurrence of Amblyomma americanum (Acari: Ixodidae) and Human Infection With Ehrlichia chaffeensis in Wisconsin, 2008-2015.

PubMed

Christenson, Megan; Lee, Xia; Larson, Scott; Johnson, Diep Hoang; Jensen, Julia; Meller, Megan; Paskewitz, Susan

2017-05-01

Because of the increasing incidence of human ehrlichiosis in Wisconsin, we assessed reports of human infections by Ehrlichia chaffeensis and the distribution of its vector, the lone star tick (Amblyomma americanum (L.)). From 2008 through 2015, 158 probable and confirmed human cases of E. chaffeensis infections were reported to the Wisconsin Department of Health Services. Five cases without travel history outside of Wisconsin were confirmed as E. chaffeensis by polymerase chain reaction. Surveillance for the vector occurred from 2008 through 2015 and was based on active and passive methods, including examination of white-tailed deer, collections from live-trapped small mammals, submissions of ticks removed from wild and domestic animals through the Wisconsin Surveillance of Animals for Ticks (SWAT) program, digital or physical submissions by the public to the University of Wisconsin Insect Diagnostic or Medical Entomology laboratories, and active tick dragging. More than 50 lone star ticks (46 adults, 6 nymphs, and 1 larva) were identified. Lone star ticks were more commonly found in south central Wisconsin, particularly in Dane County, where discovery of more than one life stage in a single year indicates possible establishment. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Bartonella, Rodents, Fleas and Ticks: a Molecular Field Study on Host-Vector-Pathogen Associations in Saxony, Eastern Germany.

PubMed

Silaghi, Cornelia; Pfeffer, Martin; Kiefer, Daniel; Kiefer, Matthias; Obiegala, Anna

2016-11-01

Bartonellae cause zoonotic diseases and are transmitted by arthropods. Rodents are reservoirs for most Bartonella spp. As the knowledge about Bartonella in rodents and their parasitizing ectoparasites is scarce in Germany, this study's objectives were to investigate Bartonella spp. in small mammals and in their ectoparasites. A total of 79 small mammals (seven species) were captured and their ectoparasites collected at seven sites around Leipzig, Saxony, Germany, in 2010 and 2011. Altogether, 79 spleen samples, 135 fleas (five species) and 365 ticks (three species) were investigated for Bartonella spp. by PCR targeting the ITS 16S-23S rRNA region. In total, 52 (65.8 %) small mammals, 73 (54.1 %) fleas and 51 (16.3 %) ticks were positive for Bartonella spp. Most small mammals were positive for uncultured Bartonella sp. (n = 29) followed by Bartonella grahamii (n = 12), Bartonella taylorii (n = 8) and Bartonella sp. N40 (n = 3). Likewise, most fleas were positive for uncultured Bartonella sp. (n = 45) followed by B. grahamii (n = 14), B. taylorii (n = 8), B. sp. N40 (n = 5) and Bartonella elizabethae (n = 2). Most ticks were positive for B. sp. (n = 19) followed by B. grahamii (n = 10), Bartonella chomelii (n = 3), B. taylorii (n = 2) and B. sp. N40 (n = 1). This study's results suggest that rodents and fleas may be reservoirs and vectors, respectively. Zoonotic B. grahamii and B. elizabethae were found in rodents and their fleas. Therefore, humans may contract Bartonella infection by contact to wild rodents. Ticks seem of minor importance in transmitting Bartonella spp. found in fleas and rodents. However, ticks might be vectors of B. chomelii.

On the potential roles of ticks and migrating birds in the ecology of West Nile virus.

PubMed

Hagman, Karl; Barboutis, Christos; Ehrenborg, Christian; Fransson, Thord; Jaenson, Thomas G T; Lindgren, Per-Eric; Lundkvist, Ake; Nyström, Fredrik; Waldenström, Jonas; Salaneck, Erik

2014-01-15

Mosquitoes are the primary vectors of West Nile virus (WNV). Ticks have, however, been suggested to be potential reservoirs of WNV. In order to investigate their role in the spread of the virus, ticks, which had been collected from birds migrating northwards from Africa to Europe, were analyzed for the potential presence of WNV-RNA. On the Mediterranean islands Capri and Antikythira a total of 14,824 birds were captured and investigated from which 747 ticks were collected. Most of the identified ticks (93%) were nymphs and larvae of Hyalomma marginatum sensu lato, most of which were or appear to be Hyalomma rufipes. Of these ticks 729 were individually screened for WNV-RNA. None of the ticks was found to be WNV positive. Thus, there was no evidence that Hyalomma marginatum s.l. ticks play a role in the spread of WNV from Africa to Europe.

[Public health pests. Arthropods and rodents as causative disease agents as well as reservoirs and vectors of pathogens].

PubMed

Faulde, M; Freise, J

2014-05-01

Globally, infectious diseases pose the most important cause of death. Among known human pathogenic diseases, approximately 50 % are zoonoses. When considering emerging infectious diseases separately 73 % currently belong to the group of zoonoses. In Central Europe, hard ticks show by far the biggest potential as vectors of agents of human disease. Lyme borreliosis, showing an estimated annual incidence between 60,000 and 214,000 cases is by far the most frequent tick-borne disease in Germany. Continually, formerly unknown disease agents could be discovered in endemic vector species. Additionally, introduction of new arthropod vectors and/or agents of disease occur constantly. Recently, five mosquito species of the genus Aedes have been newly introduced to Europe where they are currently spreading in different regions. Uncommon autochthonous transmission of dengue and chikungunya fever viruses in Southern Europe could be directly linked to these vector species and of these Ae. albopictus and Ae. japonicus are currently reported to occur in Germany. The German Protection against Infection Act only covers the control of public health pests which are either active hematophagous vectors or mechanical transmitters of agents of diseases. Use of officially recommended biocidal products aiming to interrupt transmission cycles of vector-borne diseases, is confined to infested buildings only, including sewage systems in the case of Norway rat control. Outdoor vectors, such as hard ticks and mosquitoes, are currently not taken into consideration. Additionally, adjustments of national public health regulations, detailed arthropod vector and rodent reservoir mapping, including surveillance of vector-borne disease agents, are necessary in order to mitigate future disease risks.

Multiple ferritins are vital to successful blood feeding and reproduction of the hard tick Haemaphysalis longicornis.

PubMed

Galay, Remil Linggatong; Aung, Kyaw Min; Umemiya-Shirafuji, Rika; Maeda, Hiroki; Matsuo, Tomohide; Kawaguchi, Hiroaki; Miyoshi, Noriaki; Suzuki, Hiroshi; Xuan, Xuenan; Mochizuki, Masami; Fujisaki, Kozo; Tanaka, Tetsuya

2013-05-15

Ticks are obligate hematophagous parasites and important vectors of diseases. The large amount of blood they consume contains great quantities of iron, an essential but also toxic element. The function of ferritin, an iron storage protein, and iron metabolism in ticks need to be further elucidated. Here, we investigated the function a newly identified secreted ferritin from the hard tick Haemaphysalis longicornis (HlFER2), together with the previously identified intracellular ferritin (HlFER1). Recombinant ferritins, expressed in Escherichia coli, were used for anti-serum preparation and were also assayed for iron-binding activity. RT-PCR and western blot analyses of different organs and developmental stages of the tick during blood feeding were performed. The localization of ferritins in different organs was demonstrated through an indirect immunofluorescent antibody test. RNA interference (RNAi) was performed to evaluate the importance of ferritin in blood feeding and reproduction of ticks. The midgut was also examined after RNAi using light and transmission electron microscopy. RT-PCR showed differences in gene expression in some organs and developmental stages. Interestingly, only HlFER2 was detected in the ovary during oviposition and in the egg despite the low mRNA transcript. RNAi induced a reduction in post-blood meal body weight, high mortality and decreased fecundity. The expression of vitellogenin genes was affected by silencing of ferritin. Abnormalities in digestive cells, including disrupted microvilli, and alteration of digestive activity were also observed. Taken altogether, our results show that the iron storage and protective functions of ferritin are crucial to successful blood feeding and reproduction of H. longicornis.

Population bottlenecks during the infectious cycle of the Lyme disease spirochete Borrelia burgdorferi.

PubMed

Rego, Ryan O M; Bestor, Aaron; Stefka, Jan; Rosa, Patricia A

2014-01-01

Borrelia burgdorferi is a zoonotic pathogen whose maintenance in nature depends upon an infectious cycle that alternates between a tick vector and mammalian hosts. Lyme disease in humans results from transmission of B. burgdorferi by the bite of an infected tick. The population dynamics of B. burgdorferi throughout its natural infectious cycle are not well understood. We addressed this topic by assessing the colonization, dissemination and persistence of B. burgdorferi within and between the disparate mammalian and tick environments. To follow bacterial populations during infection, we generated seven isogenic but distinguishable B. burgdorferi clones, each with a unique sequence tag. These tags resulted in no phenotypic changes relative to wild type organisms, yet permitted highly sensitive and specific detection of individual clones by PCR. We followed the composition of the spirochete population throughout an experimental infectious cycle that was initiated with a mixed inoculum of all clones. We observed heterogeneity in the spirochete population disseminating within mice at very early time points, but all clones displayed the ability to colonize most mouse tissues by 3 weeks of infection. The complexity of clones subsequently declined as murine infection persisted. Larval ticks typically acquired a reduced and variable number of clones relative to what was present in infected mice at the time of tick feeding, and maintained the same spirochete population through the molt to nymphs. However, only a random subset of infectious spirochetes was transmitted to naïve mice when these ticks next fed. Our results clearly demonstrate that the spirochete population experiences stochastic bottlenecks during both acquisition and transmission by the tick vector, as well as during persistent infection of its murine host. The experimental system that we have developed can be used to further explore the forces that shape the population of this vector-borne bacterial pathogen throughout its infectious cycle.

Genomic insights into the Ixodes scapularis tick vector of Lyme disease

PubMed Central

Gulia-Nuss, Monika; Nuss, Andrew B.; Meyer, Jason M.; Sonenshine, Daniel E.; Roe, R. Michael; Waterhouse, Robert M.; Sattelle, David B.; de la Fuente, José; Ribeiro, Jose M.; Megy, Karine; Thimmapuram, Jyothi; Miller, Jason R.; Walenz, Brian P.; Koren, Sergey; Hostetler, Jessica B.; Thiagarajan, Mathangi; Joardar, Vinita S.; Hannick, Linda I.; Bidwell, Shelby; Hammond, Martin P.; Young, Sarah; Zeng, Qiandong; Abrudan, Jenica L.; Almeida, Francisca C.; Ayllón, Nieves; Bhide, Ketaki; Bissinger, Brooke W.; Bonzon-Kulichenko, Elena; Buckingham, Steven D.; Caffrey, Daniel R.; Caimano, Melissa J.; Croset, Vincent; Driscoll, Timothy; Gilbert, Don; Gillespie, Joseph J.; Giraldo-Calderón, Gloria I.; Grabowski, Jeffrey M.; Jiang, David; Khalil, Sayed M. S.; Kim, Donghun; Kocan, Katherine M.; Koči, Juraj; Kuhn, Richard J.; Kurtti, Timothy J.; Lees, Kristin; Lang, Emma G.; Kennedy, Ryan C.; Kwon, Hyeogsun; Perera, Rushika; Qi, Yumin; Radolf, Justin D.; Sakamoto, Joyce M.; Sánchez-Gracia, Alejandro; Severo, Maiara S.; Silverman, Neal; Šimo, Ladislav; Tojo, Marta; Tornador, Cristian; Van Zee, Janice P.; Vázquez, Jesús; Vieira, Filipe G.; Villar, Margarita; Wespiser, Adam R.; Yang, Yunlong; Zhu, Jiwei; Arensburger, Peter; Pietrantonio, Patricia V.; Barker, Stephen C.; Shao, Renfu; Zdobnov, Evgeny M.; Hauser, Frank; Grimmelikhuijzen, Cornelis J. P.; Park, Yoonseong; Rozas, Julio; Benton, Richard; Pedra, Joao H. F.; Nelson, David R.; Unger, Maria F.; Tubio, Jose M. C.; Tu, Zhijian; Robertson, Hugh M.; Shumway, Martin; Sutton, Granger; Wortman, Jennifer R.; Lawson, Daniel; Wikel, Stephen K.; Nene, Vishvanath M.; Fraser, Claire M.; Collins, Frank H.; Birren, Bruce; Nelson, Karen E.; Caler, Elisabet; Hill, Catherine A.

2016-01-01

Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick–host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host ‘questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent. PMID:26856261

Comparative analysis of the roles of Ixodes persulcatus and I. trianguliceps ticks in natural foci of ixodid tick-borne borrelioses in the Middle Urals, Russia.

PubMed

Korenberg, Edward I; Kovalevskii, Yurii V; Gorelova, Natalya B; Nefedova, Valentina V

2015-04-01

Long-term studies on natural foci of ixodid tick-borne borrelioses (ITBB) have been performed in Chusovskoi district of Perm region, the Middle Urals, where the vectors of these infections are represented by two ixodid tick species: the taiga tick Ixodes persulcatus and many times less abundant vole tick I. trianguliceps. Over 10 years, more than 6000 half-engorged ticks were collected from small forest mammals using the standard procedure, and 1027 I. persulcatus and 1142 I. trianguliceps ticks, individually or in pools, were used to inoculate BSK-2 medium. As a result, 199 Borrelia isolates were obtained. Among them, 177 isolates were identified, and the rrf(5S)-rrl(23S) intergenic spacer sequence was determined in 57 isolates. The prevalence of Borrelia infection in I. persulcatus larvae and nymphs averaged 31.0 and 53.3%, while that in I. trianguliceps larvae, nymphs, and adult ticks was five to ten times lower: 2.6, 10.2, and 8.1%, respectively. Each of the two tick species was found to carry both ITBB agents circulating in the Middle Ural foci (Borrelia garinii and B. afzelii), but the set of genogroups and genovariants of these spirochetes in I. trianguliceps proved to be far less diverse. According to the available data, this tick, compared to I. persulcatus, is generally less susceptible to Borrelia infection (especially by B. afzelii). Taking into account of its relatively low abundance, it appears that I. trianguliceps cannot seriously influence the course of epizootic process in ITBB foci of the study region, whereas highly abundant I. persulcatus with the high level of Borrelia infection is obviously a key component of these parasitic systems. A similar situation may well be typical for the entire geographic range shared by the two tick species. Copyright © 2015. Published by Elsevier GmbH.

[Ticks and transmission of some important diseases by ticks].

PubMed

Gazyağci, Aycan Nuriye; Aydenızöz, Meral

2010-01-01

Ticks which are commonly found all around the world are ectoparasites which are obliged to suck blood from vertebrates such as mammals and birds during all of their periods of develeopment. They may cause toxicities and paralyses in the course of blood sucking through saliva injection and the attachment sites may become ports of entry for secondary agents. Healthy animals that are severely infested by ticks can show a decreased yield and anemia. Young and sick animals can even die. Besides this, ticks are both biological and mechanical vectors for viruses, bacteria, rickettsias, spirochaetas, protozoons and helminths. Ten percent of the ticks identified in the world are associated with 200 diseases. In this review the taxonomy and morphology of ticks, some of the important diseases they carry and the diagnosis and treatment of these diseases are mentioned.

Linkages of Weather and Climate With Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae), Enzootic Transmission of Borrelia burgdorferi, and Lyme Disease in North America

PubMed Central

Eisen, Rebecca J.; Eisen, Lars; Ogden, Nicholas H.; Beard, Charles B.

2016-01-01

Lyme disease has increased both in incidence and geographic extent in the United States and Canada over the past two decades. One of the underlying causes is changes during the same time period in the distribution and abundance of the primary vectors: Ixodes scapularis Say and Ixodes pacificus Cooley and Kohls in eastern and western North America, respectively. Aside from short periods of time when they are feeding on hosts, these ticks exist in the environment where temperature and relative humidity directly affect their development, survival, and host-seeking behavior. Other important factors that strongly influence tick abundance as well as the proportion of ticks infected with the Lyme disease spirochete, Borrelia burgdorferi, include the abundance of hosts for the ticks and the capacity of tick hosts to serve as B. burgdorferi reservoirs. Here, we explore the linkages between climate variation and: 1) duration of the seasonal period and the timing of peak activity; 2) geographic tick distributions and local abundance; 3) enzootic B. burgdorferi transmission cycles; and 4) Lyme disease cases. We conclude that meteorological variables are most influential in determining host-seeking phenology and development, but, while remaining important cofactors, additional variables become critical when exploring geographic distribution and local abundance of ticks, enzootic transmission of B. burgdorferi, and Lyme disease case occurrence. Finally, we review climate change-driven projections for future impact on vector ticks and Lyme disease and discuss knowledge gaps and research needs. PMID:26681789

Re-assessment of tick control after immunization against East Coast fever in the Eastern Province of Zambia.

PubMed

Berkvens, D L

1991-01-01

East Coast Fever, caused by the protozoon Theileria parva and transmitted by the ixodid tick Rhipicephalus appendiculatus is one of the most important cattle diseases in east and central Africa, responsible for considerable direct losses and necessitating expensive control measures. Traditionally, the disease was controlled by means of intensive tick control. The Belgian Animal Disease Control Project was requested to study the disease epizootiology and vector ecology in order to formulate and implement a control program adapted to the requirements and capabilities of the cattle owners in the Eastern Province of Zambia. The weaknesses of a rigorous tick control program were demonstrated. It was decided to initiate an immunization program in the enzootic areas. The overall calf mortality rate was lowered by 90% and it was shown that none of the other tick-borne diseases caused significant problems in the absence of tick control. The tick ecology studies had indicated that the climatic conditions in the area were so unfavourable that the important vector species (Amblyomma variegatum, Boophilus microplus and R. appendiculatus) would not attain problem levels. It was therefore recommended to suspend all tick control in the area. Control of East Coast Fever in the epizootic and disease-free areas is still a more complex issue. It appears unlikely that the latter will remain disease-free, because of the proximity of the enzootic areas and because of considerable cattle movement in the province. Given the advantages of control by immunization, it can be argued that a longterm solution should be based on this approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis of epizootic bovine abortion in Nevada and identification of the vector.

PubMed

Hall, Mark R; Hanks, Donald; Kvasnicka, William; Bosomworth, Alan; Smith, Harry; Stott, Jeffrey L; Blanchard, Myra T; Anderson, Mark L

2002-05-01

In the 43 years since the first description in California, epizootic bovine abortion (EBA) has been considered but not definitively diagnosed as a cause of late-term abortions on Nevada ranches. Examination of aborted full-term bovine fetuses obtained from Nevada ranches revealed gross abnormalities consistent with EBA (enlarged lymph nodes, petechial hemorrhages of the oral mucosa and conjunctiva, ascites, and splenohepatomegaly), and EBA was confirmed by histologic examination of fetal tissues. The histologic thymic changes were characteristic of EBA and included severe histocytic thymusitis with depletion of thymocytes, interlobular hemorrhage, and fibrinocellular exudation. The gross enlargement of lymph nodes was the result of cortical follicular hyperplasia and histiocytic lymphadenitis. In addition, widespread, predominately nonsuppurative histologic lesions typical of EBA were observed in most organs, including the brain, lung, heart, liver, and spleen. Furthermore, the presence of Ornithodorus coriaceus, the argasid tick vector of EBA, was established by tick collection using CO2 traps. The tick was identified on ranches and in geographic areas (northern and northwestern counties of Nevada) coincident with diagnosis of multiple cases of EBA. This study establishes the presence of EBA as a cause of late-term abortion in Nevada. Additionally, identification of the EBA tick vector, O. coriaceus, in the same areas as the abortions provides strong evidence that the disease is endemic.

Ticks and Fleas Infestation on East Hedgehogs (Erinaceus concolor) in Van Province, Eastern Region of Turkey

PubMed Central

Goz, Yaşar; Yilmaz, Ali Bilgin; Aydin, Abdulalim; Dicle, Yalçın

2016-01-01

Background: Ixodid ticks (Acari: İxodidae) and fleas (Siphonaptera) are the major vectors of pathogens threatening animals and human healths. The aim of our study was to detect the infestation rates of East Hedgehogs (Erinaceus concolor) with ticks and fleas in Van Province, eastern region of Turkey. Methods: We examined fleas and ticks infestation patterns in 21 hedgehogs, collected from three suburbs with the greater of number gardens. In order to estimate flea and tick infestation of hedgehogs, we immobilized the ectoparasites by treatment the body with a insecticide trichlorphon (Neguvon®-Bayer). Results: On the hedgehogs, 60 ixodid ticks and 125 fleas were detected. All of the ixodid ticks were Rhipicephalus turanicus and all of the fleas were Archaeopsylla erinacei. Infestation rate for ticks and fleas was detected 66.66 % and 100 %, respectively. Conclusion: We detected ticks (R. turanicus) and fleas (A. erinacei) in hedgehogs at fairly high rates. Since many ticks and fleas species may harbor on hedgehogs and transmit some tick-borne and flea-borne patogens, this results are the important in terms of veterinary and public health. PMID:27047971

Prevalence of Rickettsia Species (Rickettsiales: Rickettsiaceae) in Dermacentor variabilis Ticks (Acari: Ixodidae) in North Carolina.

PubMed

Kakumanu, Madhavi L; Ponnusamy, Loganathan; Sutton, Haley; Meshnick, Steven R; Nicholson, William L; Apperson, Charles S

2018-05-16

The American dog tick, Dermacentor variabilis (Say), is a vector of spotted fever group (SFG) rickettsiae, including Rickettsia rickettsii the causative organism of Rocky Mountain spotted fever (RMSF). In North Carolina, SFG rickettsioses (including RMSF) are a leading cause of tick-borne illness. Knowledge of the infection rate and geographic distribution of D. variabilis ticks infected with Rickettsia spp. provides information on the spatial distribution of public health risk. Accordingly, we extracted genomic DNA from adult D. variabilis collected from field habitats in 32 North Carolina counties from 2009 to 2013. A nested PCR assay of the 23S-5S intergenic spacer (IGS) region of Rickettsia coupled with reverse line blot hybridization (RLBH) with species-specific probes was used to detect and identify rickettsiae to species. Approximately half of the 532 tick DNA samples exhibited a band of the expected size on agarose gels, indicating infection with Rickettsia spp. RLBH analyses showed R. amblyommatis (formerly 'Candidatus R. amblyommii'), R. parkeri, and R. montanensis were predominant, while other Rickettsia species detected included R. conorii-like, R. massiliae, R. rhipicephali, R. canadensis, R. bellii, and some unknown Rickettsia spp. Some ticks were infected with more than one Rickettsia species. Notably, several Rickettsia-positive ticks harbored R. rickettsii. DNA sequencing was performed on a portion of the 23S-5S IGS amplicons and the results were concordant with RLB assay results. We conclude that Rickettsia spp. are common in D. variabilis in North Carolina. Geographic patterns in the occurrence of Rickettsia-infected D. variabilis ticks across the counties sampled are discussed.

Powassan Virus—A New Reemerging Tick-Borne Disease

PubMed Central

Fatmi, Syed Soheb; Zehra, Rija; Carpenter, David O.

2017-01-01

Powassan virus is a neurovirulent flavivirus consisting of two lineages causing meningoencephalitis. It is the only member of the tick-borne encephalitis serogroup which is present in mainland North America. With a total number of 27 cases from 1958 to 1998 and 98 cases from 1999 to 2016, reported cases have increased by 671% over the last 18 years. Powassan infection is transmitted by different tick species in different geographical regions. Ixodes scapularis is the primary vector that transmits the virus on the East Coast of US and Ixodes cookei in the Midwest and Canada, while Hemaphysalis longicornis is the vector in Russia. Powassan has no singular pathognomonic finding and presents with a wide spectrum of symptoms including severe neurological symptoms. The clinical challenge lies within the management of the disease as there is no standard diagnostic protocol and most cases are only diagnosed after a patient goes through an extensive workup for other infectious disease. The diagnosis is established by a combination of imaging and serologic tests. In case of Powassan meningoencephalitis, computed tomography scan and magnetic resonance imaging show vascular insults, which are also seen in cases of tick-borne encephalitis virus, another flavivirus of medical importance. Serologic tests are the gold standard for diagnosis, although testing is not widely available and only state health departments and Center for Disease Control and Prevention can perform Powassan-specific IgM antibody testing utilizing enzyme-linked immunosorbent assay and immunofluorescence antibody. Powassan is also of veterinary medical importance. Wildlife animals act as a reservoir to the pathogens, hence possessing threat to humans and domestic animals. This review highlights Powassan’s neurotropic presentation, epidemiology, diagnostic challenges, and prevalence. Strong emphasis is placed on establishing diagnostic protocols, widespread Powassan-specific IgM testing, role of the vector in disease presentation, and necessary preventive research. PMID:29312918

Tick-borne flavivirus infection in Ixodes scapularis larvae: development of a novel method for synchronous viral infection of ticks

PubMed Central

Mitzel, Dana N.; Wolfinbarger, James B.; Daniel Long, R.; Masnick, Max; Best, Sonja M.; Bloom, Marshall E.

2007-01-01

Following a bite from an infected tick, tick-borne flaviviruses cause encephalitis, meningitis and hemorrhagic fever in humans. Although these viruses spend most of their time in the tick, little is known regarding the virus-vector interactions. We developed a simple method for synchronously infecting Ixodes scapularis larvae with Langat virus (LGTV) by immersion in media containing the virus. This technique resulted in approximately 96% of ticks becoming infected. LGTV infection and replication were demonstrated by both viral antigen expression and the accumulation of viral RNA. Furthermore, ticks transmitted LGTV to 100% of the mice and maintained the virus through molting into the next life stage. This technique circumvents limitations present in the current methods by mimicking the natural route of infection and by using attenuated virus strains to infect ticks; thereby, making this technique a powerful tool to study both virus and tick determinants of replication, pathogenesis and transmission. PMID:17490700

Remodeling of tick cytoskeleton in response to infection with Anaplasma phagocytophilum.

PubMed

Cabezas-Cruz, Alejandro; Alberdi, Pilar; Valdes, James J; Villar, Margarita; de la Fuente, Jose

2017-06-01

The obligate intracellular pathogen Anaplasma phagocytophilum infects vertebrate and tick hosts. In this study, a genome-wide search for cytoskeleton components was performed in the tick vector, Ixodes scapularis . The available transcriptomics and proteomics data was then used to characterize the mRNA and protein levels of I. scapularis cytoskeleton components in response to A. phagocytophilum infection. The results showed that cytoskeleton components described in other model organisms were present in the I. scapularis genome. One type of intermediate filaments (lamin), a family of septins that was recently implicated in the cellular response to intracellular pathogens, and several members of motor proteins (kinesins and dyneins) that could be implicated in the cytoplasmic movements of A. phagocytophilum were found. The results showed that levels of tubulin, actin, septin, actin-related proteins and motor proteins were affected by A. phagocytophilum , probably to facilitate infection in I. scapularis . Functional studies demonstrated a role for selected cytoskeleton components in pathogen infection. These results provided a more comprehensive view of the cytoskeletal components involved in the response to A. phagocytophilum infection in ticks.

Lyme borreliosis: ten years after discovery of the etiologic agent, Borrelia burgdorferi.

PubMed

Burgdorfer, W

1991-01-01

Since the recovery of its causative agent, Borrelia burgdorferi, in 1981, Lyme borreliosis has become the most prevalent tick-borne disease in the United States as well as in Europe. Its steadily increasing clinical spectrum now includes erythema migrans, acrodermatitis chronica atrophicans, lymphadenosis beniga cutis, arthritis, myocarditis, progressive meningoencephalitis, myositis, and various ocular and skin disorders. The true incidence of Lyme borreliosis in the world is unknown. In the United States, it has increased from 2,000 cases in 1987, to more than 8,000 in 1989. It occurs now in regions where the tick vectors, Ixodes dammini and Ixodes pacificus, are absent and where other species of ticks may be responsible for maintaining and distributing the spirochete. In Europe, Lyme borreliosis has been reported from 19 countries; its occurrence coincides with the distribution of the vector tick, Ixodes ricinus and possibly Ixodes hexagonus. Specific and dependable serological tests are still not available, but development of probes for specific antigens and the polymerase chain reaction appear promising in detecting ongoing infections and in identifying B. burgdorferi in ticks, animal, and human hosts. Brief reference is made to advances in the preparation of whole cell and genetically engineered vaccines.

Crimean-Congo Hemorrhagic Fever: Tick-Host-Virus Interactions

PubMed Central

Papa, Anna; Tsergouli, Katerina; Tsioka, Katerina; Mirazimi, Ali

2017-01-01

Crimean-Congo hemorrhagic fever virus (CCHFV) is transmitted to humans by bite of infected ticks or by direct contact with blood or tissues of viremic patients or animals. It causes to humans a severe disease with fatality up to 30%. The current knowledge about the vector-host-CCHFV interactions is very limited due to the high-level containment required for CCHFV studies. Among ticks, Hyalomma spp. are considered the most competent virus vectors. CCHFV evades the tick immune response, and following its replication in the lining of the tick's midgut, it is disseminated by the hemolymph in the salivary glands and reproductive organs. The introduction of salivary gland secretions into the host cells is the major route via which CCHFV enters the host. Following an initial amplification at the site of inoculation, the virus is spread to the target organs. Apoptosis is induced via both intrinsic and extrinsic pathways. Genetic factors and immune status of the host may affect the release of cytokines which play a major role in disease progression and outcome. It is expected that the use of new technology of metabolomics, transcriptomics and proteomics will lead to improved understanding of CCHFV-host interactions and identify potential targets for blocking the CCHFV transmission. PMID:28603698

Influence of abiotic and environmental factors on the density and infection prevalence of Ixodes pacificus (Acari:Ixodidae) with Borrelia burgdorferi.

PubMed

Swei, A; Meentemeyer, R; Briggs, C J

2011-01-01

The abiotic and biotic factors that govern the spatial distribution of Lyme disease vectors are poorly understood. This study addressed the influence of abiotic and biotic environmental variables on Ixodes pacificus Cooley & Kohls (Acari:Ixodidae) nymphs, because it is the primary vector of Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner in the far-western United States. Three metrics of Lyme disease risk were evaluated: the density of nymphs, the density of infected nymphs, and the nymphal infection prevalence. This study sampled randomly located plots in oak (Quercus spp.) woodland habitat in Sonoma County, CA. Each plot was drag-sampled for nymphal ticks and tested for B. burgdorferi infection. Path analysis was used to evaluate the direct and indirect relationship between topographic, forest structure and microclimatic variables on ticks. Significant negative correlations were found between maximum temperature in the dry season and the density of infected ticks in 2006 and tick density in 2007, but we did not find a significant relationship with nymphal infection prevalence in either year. Tick density and infected tick density had an indirect, positive correlation with elevation, mediated through temperature. This study found that in certain years but not others, temperature maxima in the dry season may constrain the density and density of infected I. pacificus nymphs. In other years, biotic or stochastic factors may play a more important role in determining tick density.

Epidemiological Implications of Host Biodiversity and Vector Biology: Key Insights from Simple Models.

PubMed

Dobson, Andrew D M; Auld, Stuart K J R

2016-04-01

Models used to investigate the relationship between biodiversity change and vector-borne disease risk often do not explicitly include the vector; they instead rely on a frequency-dependent transmission function to represent vector dynamics. However, differences between classes of vector (e.g., ticks and insects) can cause discrepancies in epidemiological responses to environmental change. Using a pair of disease models (mosquito- and tick-borne), we simulated substitutive and additive biodiversity change (where noncompetent hosts replaced or were added to competent hosts, respectively), while considering different relationships between vector and host densities. We found important differences between classes of vector, including an increased likelihood of amplified disease risk under additive biodiversity change in mosquito models, driven by higher vector biting rates. We also draw attention to more general phenomena, such as a negative relationship between initial infection prevalence in vectors and likelihood of dilution, and the potential for a rise in density of infected vectors to occur simultaneously with a decline in proportion of infected hosts. This has important implications; the density of infected vectors is the most valid metric for primarily zoonotic infections, while the proportion of infected hosts is more relevant for infections where humans are a primary host.

First documentation of ivermectin resistance in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)

USDA-ARS?s Scientific Manuscript database

The brown dog tick, Rhipicephalus sanguineus sensu lato (Latreille, 1806), is an ectoparasite and disease vector of significant veterinary and public health importance that is distributed widely around the world. The indiscriminate use of chemicals for tick control exerts a strong selective pressure...

The transcription factor relish controls anaplasma marginale infection in the bovine tick rhipicephalus microplus

USDA-ARS?s Scientific Manuscript database

Rhipicephalus microplus is an important biological vector of Anaplasma marginale, the etiological agent of bovine anaplasmosis. The knowledge of tick immune responses to control bacterial infections remains limited. In this study, we demonstrate that transcription factor Relish from the Imd signalin...

Soft tick sampling and collection

USDA-ARS?s Scientific Manuscript database

Several soft tick species in the genus Ornithodoros are vectors of African swine fever virus (ASFV) in nature, or known to be susceptible to infection. African swine fever (ASF) caused by ASFV is considered one of the most serious transboundary swine diseases because of its high lethality for pigs, ...

Indigenous and crossbred cattle--a comparison of resistance to ticks and implications for their strategic control in Zimbabwe.

PubMed

Fivaz, B H; de Waal, D T; Lander, K

1992-05-01

A comparison of the tick resistance of indigenous Mashona and crossbred Afrikander x Sussex oxen following natural tick infestation indicated that significantly more African blue ticks Boophilus decoloratus were found on the crossbred than the indigenous cattle (P < 0.05). The two groups of cattle were exposed to Babesia bigemina and Theileria taurotragi as indicated by high antibody titres on the indirect fluorescent antibody test, but no antibodies could be demonstrated to Anaplasma marginale and T. parva bovis despite the presence of their vectors. Rhipicephalus appendiculatus, Hyalomma truncatum and H. marginatum rufipes showed a seasonal distribution. The implications of the findings in terms of strategic tick control are discussed.

Projected economic losses due to vector and vector-borne parasitic diseases in livestock of India and its significance in implementing the concept of integrated practices for vector management

PubMed Central

Narladkar, B. W.

2018-01-01

Broadly, species of arthropods infesting livestock are grouped into flies (biting and non-biting), fleas, lice (biting and sucking), ticks (soft and hard), and mites (burrowing, non-burrowing, and follicular). Among which, biting and non-biting flies and ticks are the potent vectors for many bacterial, viral, rickettsial, and protozoan diseases. Vectors of livestock are having economic significance on three points (1) direct losses from their bite and annoyance, worries, and psychological disturbances produced during the act of biting and feeding, (2) diseases they transmit, and (3) expenditure incurred for their control. Flies such as Culicoides spp. and Musca spp. and various species of hard ticks play important role in disease transmission in addition to their direct effects. For control of vectors, recent concept of integrated pest management (IPM) provides the best solution and also addresses the problems related to acaricide resistance and environmental protection from hazardous chemicals. However, to successfully implement the concept of IPM, for each vector species, estimation of two monitory benchmarks, i.e., economic injury level (EIL) and economic threshold level (ETL) is essential prerequisite. For many vector species and under several circumstances, estimation of EIL and ETL appears to be difficult. Under such scenario, although may not be exact, an approximate estimate can be accrued by taking into account several criteria such as percent prevalence of vectors in a geographical area, percent losses produced, total livestock population, and current prices of livestock products such as milk, meat, and wool. Method for approximate estimation is first time described and elaborated in the present review article. PMID:29657396

Emerging horizons for tick-borne pathogens: from the ‘one pathogen–one disease’ vision to the pathobiome paradigm

PubMed Central

Vayssier-Taussat, Muriel; Kazimirova, Maria; Hubalek, Zdenek; Hornok, Sándor; Farkas, Robert; Cosson, Jean-François; Bonnet, Sarah; Vourch, Gwenaël; Gasqui, Patrick; Mihalca, Andrei Daniel; Plantard, Olivier; Silaghi, Cornelia; Cutler, Sally; Rizzoli, Annapaola

2015-01-01

Ticks, as vectors of several notorious zoonotic pathogens, represent an important and increasing threat for human and animal health in Europe. Recent applications of new technology revealed the complexity of the tick microbiome, which may affect its vectorial capacity. Appreciation of these complex systems is expanding our understanding of tick-borne pathogens, leading us to evolve a more integrated view that embraces the ‘pathobiome’; the pathogenic agent integrated within its abiotic and biotic environments. In this review, we will explore how this new vision will revolutionize our understanding of tick-borne diseases. We will discuss the implications in terms of future research approaches that will enable us to efficiently prevent and control the threat posed by ticks. PMID:26610021

Inventory and update on argasid ticks and associated pathogens in Algeria.

PubMed

Lafri, I; Benredjem, W; Neffah-Baaziz, F; Lalout, R; Abdelouahed, K; Gassen, B; Bakhouch, S; Chergui, M; Karakellah, M; Adjmi-Hamoudi, H; Bitam, I

2018-05-01

Argasid ticks include vectors of relapsing fevers caused by Borrelia spp. in humans, and they can transmit arboviruses and other bacterial pathogens. Knowledge about soft ticks ( Ixodida: Argasidae ) in Algeria is incomplete, and distribution data need to be updated. Here we report a series of entomologic investigations that we conducted in five different areas in Algeria between 2012 and 2015. Ticks were identified by entomologic keys and molecular tools (16S rRNA gene). Six distinct species belonging to two genera were identified, including Ornithodoros capensis s.s., Ornithodoros rupestris, Ornithodoros occidentalis, Ornithodoros erraticus, Ornithodoros sonrai and Argas persicus. The present study highlights the distribution of soft ticks, the establishment of an update inventory with nine species and associated pathogens detected in argasid ticks in Algeria.

Detection of Borrelia burgdorferi and Anaplasma phagocytophilum in the black-legged tick, Ixodes scapularis, within southwestern Pennsylvania.

PubMed

Brown, Scott M; Lehman, Preston M; Kern, Ryan A; Henning, Jill D

2015-06-01

Prevalence studies of Borrelia burgdorferi and Anaplasma phagocytophilum have been rare for ticks from southwestern Pennsylvania. We collected 325 Ixodes scapularis ticks between 2011 and 2012 from four counties in southwestern Pennsylvania. We tested for the presence of Borrelia burgdorferi and Anaplasma phagocytophilum using PCR. Of the ticks collected from Pennsylvania, B. burgdorferi (causative agent of Lyme disease) was present in 114/325 (35%) and Anaplasma phagocytophilum (causative agent of Human Granulocytic Anaplasmosis) was present in 48/325 (15%) as determined by PCR analysis. © 2015 The Society for Vector Ecology.

Tick parasites of rodents in Romania: host preferences, community structure and geographical distribution

PubMed Central

2012-01-01

Background Ticks are among the most important vectors of zoonotic diseases in temperate regions of Europe, with widespread distribution and high densities, posing an important medical risk. Most ticks feed on a variety of progressively larger hosts, with a large number of small mammal species typically harbouring primarily the immature stages. However, there are certain Ixodidae that characteristically attack micromammals also during their adult stage. Rodents are widespread hosts of ticks, important vectors and competent reservoirs of tick-borne pathogens. Micromammal-tick associations have been poorly studied in Romania, and our manuscript shows the results of a large scale study on tick infestation epidemiology in rodents from Romania. Methods Rodents were caught using snap-traps in a variety of habitats in Romania, between May 2010 and November 2011. Ticks were individually collected from these rodents and identified to species and development stage. Frequency, mean intensity, prevalence and its 95% confidence intervals were calculated using the EpiInfo 2000 software. A p value of <0.05 was considered statistically significant. Results We examined 423 rodents (12 species) collected from six counties in Romania for the presence of ticks. Each collected tick was identified to species level and the following epidemiological parameters were calculated: prevalence, mean intensity and mean abundance. The total number of ticks collected from rodents was 483, with eight species identified: Ixodes ricinus, I. redikorzevi, I. apronophorus, I. trianguliceps, I. laguri, Dermacentor marginatus, Rhipicephalus sanguineus and Haemaphysalis sulcata. The overall prevalence of tick infestation was 29.55%, with a mean intensity of 3.86 and a mean abundance of 1.14. Only two polyspecific infestations were found: I. ricinus + I. redikorzevi and I. ricinus + D. marginatus. Conclusions Our study showed a relatively high diversity of ticks parasitizing rodents in Romania. The most common tick in rodents was I. ricinus, followed by I. redikorzevi. Certain rodents seem to host a significantly higher number of tick species than others, the most important within this view being Apodemus flavicollis and Microtus arvalis. The same applies for the overall prevalence of tick parasitism, with some species more commonly infected (M. arvalis, A. uralensis, A. flavicollis and M. glareolus) than others. Two rodent species (Mus musculus, Rattus norvegicus) did not harbour ticks at all. Based on our results we may assert that rodents generally can act as good indicators for assessing the distribution of certain tick species. PMID:23171665

Epidemiological surveillance of capybaras and ticks on warning area for Brazilian spotted fever

PubMed Central

Brites-Neto, José; Brasil, Jardel; Roncato Duarte, Keila Maria

2015-01-01

Aim: The vulnerability of tropical developing countries to the emerging disease constitutes a critical phenomenon in which the invasion of wild niches by human hosts, contributes to expansion of zoonotic diseases, such as the Brazilian spotted fever (BSF). This study performed a diagnosis of species occurrence of their hosts (Hydrochoerus hydrochaeris) and vectors (Amblyomma sculptum and Amblyomma dubitatum) on the warning area for this reemerging disease in Brazil. Materials and Methods: The study was conducted in a warning area for BSF in the city of Americana, São Paulo state. The occurrence of capybaras was registered by use of binoculars and GPS equipment and 24 acarological researches were performed through 180 CO2 traps. Samples of adult ticks were dissected for salivary glands removal, DNA extraction, and evaluation by polymerase chain reaction (PCR) being tested by initial gltA-PCR, ompA-PCR, and Rickettsia bellii-specific PCR, with the positive samples subjected to sequencing. Results: Eleven clusters of capybaras (total of 71 individuals), were observed along the riparian of Ribeirão Quilombo and 7,114 specimens of A. sculptum and 7,198 specimens of A. dubitatum were collected in this same area. About 568 samples of adult ticks were dissected for salivary glands removal, DNA extraction and evaluation by gltA-PCR, with results of 1.94% (11/568) of positive samples. Results for the initial gltA-PCR indicated none positive sample to Rickettsia species into A. sculptum and 11 positive samples to A. dubitatum. These samples were negative to the ompA-PCR and positive to the Rickettsia bellii-specific PCR protocol and subjected to DNA sequencing, whose result indicated 100% similarity to Rickettsia bellii. The distribution of tick species A. sculptum and A. dubitatum was configured regarding to the biotic potential of the riparian areas, measuring the risks for BSF in peri-urban areas of Americana. Conclusion: These results confirmed a status of epidemiological warning with a strong association of the amplifiers hosts of Rickettsia and tick vectors for the transmission of BSF to humans in this region. PMID:27047211

Prevalence of Borrelia miyamotoi and Borrelia burgdorferi sensu lato in questing ticks from a recreational coniferous forest of East Saxony, Germany.

PubMed

Szekeres, Sándor; Lügner, Jenny; Fingerle, Volker; Margos, Gabriele; Földvári, Gábor

2017-10-01

The hard tick Ixodes ricinus is the most important vector of tick-transmitted pathogens in Europe, frequently occurring in urban parks and greenbelts utilized for recreational activities. This species is the most common vector of the causative agents of Lyme borreliosis in Europe. Similarly, the species spreads Borrelia miyamotoi, causing a relapsing-fever like illness. A total of 1774 Ixodes ricinus (50 females, 68 males, 840 nymphs and 818 larvae) were collected with flagging between March and September 2014 in a coniferous forest patch in Niederkaina near the town of Bautzen in Saxony, Germany. To measure questing tick density a time-based density estimating method was utilized. From each month, a total of 100 adults and nymphal ticks and all larvae (pools of 10 individuals per tube/month) were selected for the molecular analyses. For simultaneous detection of B. burgdorferi s.l. and B. miyamotoi a duplex real-time PCR targeting the flaB locus was performed. Prevalence of B. burgdorferi s.l. was 9.4% (female: 6%, male: 2.9%, nymph: 12.2%, larva: 0%) and minimum prevalence of B. miyamotoi was 1.2% (female: 0%, male: 4.3%, nymph: 2.8%, larva: 0.1%) in the 714 samples with real-time polymerase chain reaction. A real-time PCR reaction was utilized first to target the histone-like protein gene (hbb) of B. burgdorferi s.l., a hemi-nested outer surface protein (ospA) gene conventional PCR was then performed followed by a restriction enzyme analysis to distinguish B. burgdorferi s.l. genospecies. Seven B. afzelii, one B. burgdorferi s.s., one B. bavariensis and four B. miyamotoi infections were confirmed. Prevalence of Lyme borreliosis spirochetes was significantly higher in nymphs than in adults (p<0.01, Fisher exact test) probably due to the diluting effect of the local roe deer population. Our data highlight the potential risk of human infection with the emerging pathogen B. miyamotoi within the study area. Copyright © 2017 Elsevier GmbH. All rights reserved.

Tick-Associated Diseases: Symptoms, Treatment and Prevention

ERIC Educational Resources Information Center

Anderson, Alice; Chaney, Elizabeth

2009-01-01

According to the Centers for Disease Control and Prevention (CDC), there are eleven tick-associated diseases prevalent in the United States. Most commonly diagnosed are Lyme disease, anaplasmosis (ehrlichiosis) and babeisois, with Lyme disease being the most common vector-borne disease in the country. In southeastern states, studies have shown the…

The complexity of Rhipicephalus (Boophilus) microplus genome characterised through detailed analysis of two BAC clones

USDA-ARS?s Scientific Manuscript database

Background: Rhipicephalus (Boophilus) microplus (Rmi) a major cattle ectoparasite and tick borne disease vector, impacts on animal welfare and industry productivity. In arthropod research there is an absence of a complete Chelicerate genome, which includes ticks, mites, spiders, scorpions and crusta...

Acetylcholinesterase of Rhipicephalus (Boophilus) microplus and Phlebotomus papatasi: Gene identification, expression, and biochemical properties of recombinant proteins

USDA-ARS?s Scientific Manuscript database

Rhipicephalus (Boophilus) microplus (Bm) ticks are vectors of bovine babesiosis and anaplasmosis. Tick resistance to organophosphate (OP) acaricide involves acetylcholinesterase (AChE) insensitivity to OP and metabolic detoxification. Sequencing and in vitro expression of Bm genes encoding AChE allo...

Geno- and phenotypic characteristics of a transfected babesia bovis 6-Cys-E knockout clonal line

USDA-ARS?s Scientific Manuscript database

Babesia bovis is an intra-erythrocytic tick transmitted apicomplexan protozoan parasite. It has a complex life style including asexual replication in the mammalian host and sexual replication occurring in the midgut of host tick vector, typically, Rhipicephalus microplus. Previous evidence showed th...

Functional and morphological analysis of putative chemoreception-related proteins in the lone star tick, Amblyomma americanum

USDA-ARS?s Scientific Manuscript database

Ehrlichiosis, a potentially fatal infection, is caused by rickettsial bacteria transmitted by the lone star tick, Amblyomma americanum. We previously analyzed the chemosensory appendage proteome of A. americanum as part of a project to develop new chemosensory-based vector control methods. Among the...

Recurrent evolution of host and vector association in bacteria of the Borrelia burgdorferi sensu lato species complex.

PubMed

Becker, Noémie S; Margos, Gabriele; Blum, Helmut; Krebs, Stefan; Graf, Alexander; Lane, Robert S; Castillo-Ramírez, Santiago; Sing, Andreas; Fingerle, Volker

2016-09-15

The Borrelia burgdorferi sensu lato (s.l.) species complex consists of tick-transmitted bacteria and currently comprises approximately 20 named and proposed genospecies some of which are known to cause Lyme Borreliosis. Species have been defined via genetic distances and ecological niches they occupy. Understanding the evolutionary relationship of species of the complex is fundamental to explaining patterns of speciation. This in turn forms a crucial basis to frame testable hypotheses concerning the underlying processes including host and vector adaptations. Illumina Technology was used to obtain genome-wide sequence data for 93 strains of 14 named genospecies of the B. burgdorferi species complex and genomic data already published for 18 additional strain (including one new species) was added. Phylogenetic reconstruction based on 114 orthologous single copy genes shows that the genospecies represent clearly distinguishable taxa with recent and still ongoing speciation events apparent in Europe and Asia. The position of Borrelia species in the phylogeny is consistent with host associations constituting a major driver for speciation. Interestingly, the data also demonstrate that vector associations are an additional driver for diversification in this tick-borne species complex. This is particularly obvious in B. bavariensis, a rodent adapted species that has diverged from the bird-associated B. garinii most likely in Asia. It now consists of two populations one of which most probably invaded Europe following adaptation to a new vector (Ixodes ricinus) and currently expands its distribution range. The results imply that genotypes/species with novel properties regarding host or vector associations have evolved recurrently during the history of the species complex and may emerge at any time. We suggest that the finding of vector associations as a driver for diversification may be a general pattern for tick-borne pathogens. The core genome analysis presented here provides an important source for investigations of the underlying mechanisms of speciation in tick-borne pathogens.

Potential impact of climate change on emerging vector-borne and other infections in the UK.

PubMed

Baylis, Matthew

2017-12-05

Climate is one of several causes of disease emergence. Although half or more of infectious diseases are affected by climate it appears to be a relatively infrequent cause of human disease emergence. Climate mostly affects diseases caused by pathogens that spend part of their lifecycle outside of the host, exposed to the environment. The most important routes of transmission of climate sensitive diseases are by arthropod (insect and tick) vectors, in water and in food. Given the sensitivity of many diseases to climate, it is very likely that at least some will respond to future climate change. In the case of vector-borne diseases this response will include spread to new areas. Several vector-borne diseases have emerged in Europe in recent years; these include vivax malaria, West Nile fever, dengue fever, Chikungunya fever, leishmaniasis, Lyme disease and tick-borne encephalitis. The vectors of these diseases are mosquitoes, sand flies and ticks. The UK has endemic mosquito species capable of transmitting malaria and probably other pathogens, and ticks that transmit Lyme disease. The UK is also threatened by invasive mosquito species known to be able to transmit West Nile, dengue, chikungunya and Zika, and sand flies that spread leishmaniasis. Warmer temperatures in the future will increase the suitability of the UK's climate for these invasive species, and increase the risk that they may spread disease. While much attention is on invasive species, it is important to recognize the threat presented by native species too. Proposed actions to reduce the future impact of emerging vector-borne diseases in the UK include insect control activity at points of entry of vehicles and certain goods, wider surveillance for mosquitoes and sand flies, research into the threat posed by native species, increased awareness of the medical profession of the threat posed by specific diseases, regular risk assessments, and increased preparedness for the occurrence of a disease emergency.

Complete genomic sequence of Powassan virus: evaluation of genetic elements in tick-borne versus mosquito-borne flaviviruses.

PubMed

Mandl, C W; Holzmann, H; Kunz, C; Heinz, F X

1993-05-01

The complete nucleotide sequence of the positive-stranded RNA genome of the tick-borne flavivirus Powassan (10,839 nucleotides) was elucidated and the amino acid sequence of all viral proteins was derived. Based on this sequence as well as serological data, Powassan virus represents the most divergent member of the tick-borne serocomplex within the genus flaviviruses, family Flaviviridae. The primary nucleotide sequence and potential RNA secondary structures of the Powassan virus genome as well as the protein sequences and the reactivities of the virion with a panel of monoclonal antibodies were compared to other tick-borne and mosquito-borne flaviviruses. These analyses corroborated significant differences between tick-borne and mosquito-borne flaviviruses, but also emphasized structural elements that are conserved among both vector groups. The comparisons among tick-borne flaviviruses revealed conserved sequence elements that might represent important determinants of the tick-borne flavivirus phenotype.

Detection of Babesia spp. in Dogs and Their Ticks From Peninsular Malaysia: Emphasis on Babesia gibsoni and Babesia vogeli Infections in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae).

PubMed

Prakash, Batah Kunalan; Low, Van Lun; Vinnie-Siow, Wei Yin; Tan, Tiong Kai; Lim, Yvonne Ai-Lian; Morvarid, Akhavan Rezaei; AbuBakar, Sazaly; Sofian-Azirun, Mohd

2018-05-12

Canine babesiosis is an emerging tick-borne disease with a worldwide distribution, including Malaysia. While the prevalence of Babesia has been documented from dogs in Malaysia, occurrence of Babesia has been relatively little studied in their tick vectors. Accordingly, a total of 240 dogs and 140 Rhipicephalus sanguineus sensu lato (s.l.) (Acari: Ixodidae) ticks from Malaysia were molecularly screened for the presence of Babesia protozoa in the present study. Babesia gibsoni was only detected in ticks (1.4%), whereas Babesia vogeli was detected in both ticks (1.4%) and dogs (2.1%). This study highlights the detection of B. gibsoni and B. vogeli for the first time, in both adult and nymphal stages of R. sanguineus s.l. in Malaysia, suggesting the potential role of this tick species in transmitting canine babesiosis.

Lumpy skin disease: Attempted propagation in tick cell lines and presence of viral DNA in field ticks collected from naturally-infected cattle

PubMed Central

Tuppurainen, E.S.M.; Venter, E.H.; Coetzer, J.A.W.; Bell-Sakyi, L.

2015-01-01

Lumpy skin disease (LSD) is of substantial economic importance for the cattle industry in Africa and the Near and Middle East. Several insect species are thought to transmit the disease mechanically. Recent transmission studies have demonstrated the first evidence for a role of hard (ixodid) ticks as vectors of lumpy skin disease virus (LSDV). The aim of this study was to attempt in vitro growth of the virus in Rhipicephalus spp. tick cell lines and investigate in vivo the presence of the virus in ticks collected from cattle during LSD outbreaks in Egypt and South Africa. No evidence was obtained for replication of LSDV in tick cell lines although the virus was remarkably stable, remaining viable for 35 days at 28 °C in tick cell cultures, in growth medium used for tick cells and in phosphate buffered saline. Viral DNA was detected in two-thirds of the 56 field ticks, making this the first report of the presence of potentially virulent LSDV in ticks collected from naturally infected animals. PMID:25468765

Tissue Localization and Variation of Major Symbionts in Haemaphysalis longicornis, Rhipicephalus haemaphysaloides, and Dermacentor silvarum in China.

PubMed

Wang, Mengfei; Zhu, Dan; Dai, Jianfeng; Zhong, Zhengwei; Zhang, Yi; Wang, Jingwen

2018-05-15

Ticks are important disease vectors, as they transmit a variety of human and animal pathogens worldwide. Symbionts that coevolved with ticks confer crucial benefits to their host in nutrition metabolism, fecundity, and vector competence. Although over 100 tick species have been identified in China, general information on tick symbiosis is limited. Here, we visualized the tissue distribution of Coxiella sp. and Rickettsia sp. in lab-reared Haemaphysalis longicornis and Rhipicephalus haemaphysaloides by fluorescent in situ hybridization. We found that Coxiella sp. colonized exclusively the Malpighian tubules and ovaries of H. longicornis , while Rickettsia sp. additionally colonized the midgut of R. haemaphysaloides We also investigated the population structure of microbiota in Dermacentor silvarum ticks collected from Inner Mongolia, China, and found that Coxiella , Rickettsia , and Pseudomonas are the three dominant genera. No significant difference in microbiota composition was found between male and female D. silvarum ticks. We again analyzed the tissue localization of Coxiella sp. and Rickettsia sp. and found that they displayed tissue tropisms similar to those in R. haemaphysaloides , except that Rickettsia sp. colonized the nuclei of spermatids instead of ovaries in D. silvarum Altogether, our results suggest that Coxiella sp. and Rickettsia sp. are the main symbionts in the three ticks and reside primarily in midgut, Malpighian tubules, and reproductive tissues, but their tissue distribution varies in association with species and sexes. IMPORTANCE Tick-borne diseases constitute a major public health burden, as they are increasing in frequency and severity worldwide. The presence of symbionts helps ticks to metabolize nutrients, promotes fecundity, and influences pathogen infections. Increasing numbers of tick-borne pathogens have been identified in China; however, knowledge of native ticks, especially tick symbiosis, is limited. In this study, we analyze the distribution of Coxiella sp. and Rickettsia sp. in tissues of laboratory-reared Haemaphysalis longicornis and Rhipicephalus haemaphysaloides and field-collected Dermacentor silvarum We found that the localization patterns of Coxiella sp. in three Chinese tick species were similar to those of other tick species. We also found a previously undefined intracellular localization of Rickettsia sp. in tick midgut and spermatids. In addition, we demonstrate that tissue tropisms of symbionts vary between species and sexes. Our findings provide new insights into the tissue localization of symbionts in native Chinese ticks and pave the way for further understanding of their functional capabilities and symbiotic interactions with ticks. Copyright © 2018 American Society for Microbiology.

Evaluation of the United States Department of Agriculture Northeast Area-Wide Tick Control Project by Meta-Analysis

PubMed Central

Brei, Brandon; George, John E.; Pound, J. Mathews; Miller, J. Allen; Daniels, Thomas J.; Falco, Richard C.; Stafford, Kirby C.; Schulze, Terry L.; Mather, Thomas N.; Carroll, John F.; Fish, Durland

2009-01-01

Abstract As part of the Northeast Area-wide Tick Control Project (NEATCP), meta-analyses were performed using pooled data on the extent of tick-vector control achieved through seven concurrent studies, conducted within five states, using U.S. Department of Agriculture “4-Poster” devices to deliver targeted-acaricide to white-tailed deer. Although reductions in the abundance of all life-stages of Ixodes scapularis were the measured outcomes, this study focused on metrics associated with I. scapularis nymphal tick densities as this measure has consistently proven to directly correlate with human risk of acquiring Lyme disease. Since independent tick sampling schemes were undertaken at each of the five environmentally distinct study locations, a meta-analytic approach permitted estimation of a single true control-effect size for each treatment year of the NEATCP. The control-effect is expressed as the annual percent I. scapularis nymphal control most consistent with meta-analysis data for each treatment year. Our meta-analyses indicate that by the sixth treatment year, the NEATCP effectively reduced the relative density of I. scapularis nymphs by 71% on the 5.14 km2 treatment sites, corresponding to a 71% lower relative entomologic risk index for acquiring Lyme disease. PMID:19650737

Vector-Borne Diseases in Stray Dogs in Peninsular Malaysia and Molecular Detection of Anaplasma and Ehrlichia spp. from Rhipicephalus sanguineus (Acari: Ixodidae) Ticks.

PubMed

Koh, Fui Xian; Panchadcharam, Chandrawathani; Tay, Sun Tee

2016-01-01

Little data are available on the prevalence and transmission of vector-borne diseases in stray dogs in Peninsular Malaysia. This study was designed to determine the occurrence of vector-borne pathogens in Malaysian stray dogs using serological and molecular approaches. In total, 48 dog blood samples were subjected to serological analysis using SNAP 4Dx kit (IDEXX Laboratories, Westbrook, ME). The presence of Ehrlichia and Anaplasma DNA in the dog blood samples and Rhipicephalus sanguineus (Latreille) ticks was detected using nested polymerase chain reaction assays. Positive serological findings against Ehrlichia canis and Anaplasma phagocytophilum were obtained in 17 (39.5%) and four (9.3%) of 43 dog samples, respectively. None of the dog blood samples were positive for Borrelia burgdorferi and Dirofilaria immitis. DNA of E. canis and A. phagocytophilum was detected in 12 (25.5%) and two (4.3%) of 47 dog blood samples, and 17 (51.5%) and one (3.0%) of 33 R. sanguineus ticks, respectively. Additionally, DNA of Ehrlichia spp. closely related to Ehrlichia chaffeensis was detected in two (6.1%) R. sanguineus ticks. This study highlights the prevalence of anaplasmosis and ehrlichiosis in dogs in Malaysia. Due to the zoonotic potential of Ehrlichia and Anaplasma spp., appropriate measures should be instituted for prevention and control of vector-borne diseases in dogs. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Molecular characterization of Hepatozoon felis in Rhipicephalus sanguineus ticks infested on captive lions (Panthera leo).

PubMed

Bhusri, Benjaporn; Sariya, Ladawan; Mongkolphan, Chalisa; Suksai, Parut; Kaewchot, Supakarn; Changbunjong, Tanasak

2017-09-01

Hepatozoon spp. are protozoan parasites that infect a wide range of domestic and wild animals. The infection occurs by ingestion of an infected tick. This study was carried out to detect and characterize Hepatozoon spp. in ticks collected from captive lions ( Panthera leo ) in Thailand based on the partial 18S rRNA gene sequence. A total of 30 ticks were collected and identified as Rhipicephalus sanguineus . The collected ticks were separated into 10 tick pools by sex and life stages. Of the 10 tick pools examined, only one (10%) was found to be infected with the Hepatozoon species. Sequencing and phylogenetic analysis showed a clustering of the partial 18S rRNA gene sequence like that of H. felis from the GenBank database. This is the first report of H. felis in R. sanguineus ticks collected from captive lions in Thailand. Our results indicated that R. sanguineus may be a possible vector of feline Hepatozoon in Thailand.

Full-Genome Characterisation of Orungo, Lebombo and Changuinola Viruses Provides Evidence for Co-Evolution of Orbiviruses with Their Arthropod Vectors

PubMed Central

Mohd Jaafar, Fauziah; Belhouchet, Mourad; Belaganahalli, Manjunatha; Tesh, Robert B.; Mertens, Peter P. C.; Attoui, Houssam

2014-01-01

The complete genomes of Orungo virus (ORUV), Lebombo virus (LEBV) and Changuinola virus (CGLV) were sequenced, confirming that they each encode 11 distinct proteins (VP1-VP7 and NS1-NS4). Phylogenetic analyses of cell-attachment protein ‘outer-capsid protein 1′ (OC1), show that orbiviruses fall into three large groups, identified as: VP2(OC1), in which OC1 is the 2nd largest protein, including the Culicoides transmitted orbiviruses; VP3(OC1), which includes the mosquito transmitted orbiviruses; and VP4(OC1) which includes the tick transmitted viruses. Differences in the size of OC1 between these groups, places the T2 ‘subcore-shell protein’ as the third largest protein ‘VP3(T2)’ in the first of these groups, but the second largest protein ‘VP3(T2)’ in the other two groups. ORUV, LEBV and CGLV all group with the Culicoides-borne VP2(OC1)/VP3(T2) viruses. The G+C content of the ORUV, LEBV and CGLV genomes is also similar to that of the Culicoides-borne, rather than the mosquito-borne, or tick borne orbiviruses. These data suggest that ORUV and LEBV are Culicoides- rather than mosquito-borne. Multiple isolations of CGLV from sand flies suggest that they are its primary vector. OC1 of the insect-borne orbiviruses is approximately twice the size of the equivalent protein of the tick borne viruses. Together with internal sequence similarities, this suggests its origin by duplication (concatermerisation) of a smaller OC1 from an ancestral tick-borne orbivirus. Phylogenetic comparisons showing linear relationships between the dates of evolutionary-separation of their vector species, and genetic-distances between tick-, mosquito- or Culicoides-borne virus-groups, provide evidence for co-evolution of the orbiviruses with their arthropod vectors. PMID:24475112

Distribution of tick-borne diseases in China

PubMed Central

2013-01-01

As an important contributor to vector-borne diseases in China, in recent years, tick-borne diseases have attracted much attention because of their increasing incidence and consequent significant harm to livestock and human health. The most commonly observed human tick-borne diseases in China include Lyme borreliosis (known as Lyme disease in China), tick-borne encephalitis (known as Forest encephalitis in China), Crimean-Congo hemorrhagic fever (known as Xinjiang hemorrhagic fever in China), Q-fever, tularemia and North-Asia tick-borne spotted fever. In recent years, some emerging tick-borne diseases, such as human monocytic ehrlichiosis, human granulocytic anaplasmosis, and a novel bunyavirus infection, have been reported frequently in China. Other tick-borne diseases that are not as frequently reported in China include Colorado fever, oriental spotted fever and piroplasmosis. Detailed information regarding the history, characteristics, and current epidemic status of these human tick-borne diseases in China will be reviewed in this paper. It is clear that greater efforts in government management and research are required for the prevention, control, diagnosis, and treatment of tick-borne diseases, as well as for the control of ticks, in order to decrease the tick-borne disease burden in China. PMID:23617899

Experimental evidence against transmission of Hepatozoon canis by Ixodes ricinus.

PubMed

Giannelli, Alessio; Ramos, Rafael Antonio Nascimento; Dantas-Torres, Filipe; Mencke, Norbert; Baneth, Gad; Otranto, Domenico

2013-09-01

Hepatozoon canis is among the most widespread tick-borne protozoa infecting domestic and wild carnivores. Its distribution is related to the occurrence of its major vector, the brown dog tick Rhipicephalus sanguineus. However, the role of Ixodes ricinus as a vector of H. canis has been hypothesized. In the present study, the development of H. canis was investigated in I. ricinus and R. sanguineus nymphs collected from a naturally infested dog. All I. ricinus ticks examined (n=133) were negative by cytological examination at days 20, 30, and 90 post collection, although H. canis DNA was detected in one nymph at day 20 and in 2 nymphs at day 30 post collection. On the other hand, H. canis sporogony was documented by cytology, and H. canis DNA was detected by PCR in R. sanguineus at day 30 post collection. These results indicate that H. canis sporogony does not occur in I. ricinus, but in R. sanguineus, suggesting that I. ricinus does not act as a vector of H. canis. Copyright © 2013 Elsevier GmbH. All rights reserved.

The Babesia divergens Asia Lineage Is Maintained through Enzootic Cycles between Ixodes persulcatus and Sika Deer in Hokkaido, Japan.

PubMed

Zamoto-Niikura, Aya; Tsuji, Masayoshi; Qiang, Wei; Morikawa, Shigeru; Hanaki, Ken-Ichi; Holman, Patricia J; Ishihara, Chiaki

2018-04-01

Parasites of the Babesia divergens Asia lineage, which are closely related to B. divergens in Europe and Babesia sp. strain MO1 in the United States, were recently reported in sika deer ( Cervus nippon ) in eastern Japan. To identify the tick vector(s) for this parasite, we conducted a field survey in Hokkaido, Japan, where the infection rate in sika deer is the highest in the country. A specific PCR system which detects and discriminates between lineages within B. divergens and between those lineages and Babesia venatorum showed that Ixodes persulcatus (11/822), but not sympatric Ixodes ovatus (0/595) or Haemaphysalis sp. (0/163) ticks, carried B. divergens Asia lineage. Genomic DNA was archived from salivary glands of partially engorged I. persulcatus females and three isolates of B. divergens Asia lineage were newly described. The 18S rRNA gene sequence of the isolates formed the Asia lineage cluster with those previously described in sika deer isolates. One salivary gland also contained parasites of Babesia microti U.S. lineage, which were subsequently isolated in a hamster in vivo B. venatorum (strain Etb5) was also detected in one I. persulcatus tick. The 18S rRNA sequence of Etb5 was 99.7% identical to that of B. venatorum (AY046575) and was phylogenetically positioned in a taxon composed of B. venatorum isolates from Europe, China, and Russia. The geographical distribution of I. persulcatus is consistent with that of B. divergens in sika deer in Japan. These results suggest that I. persulcatus is a principal vector for B. divergens in Japan and Eurasia, where I. persulcatus is predominantly distributed. IMPORTANCE The Babesia divergens Asia lineage of parasites closely related to B. divergens in Europe and Babesia sp. MO1 in the United States was recently reported in Cervus nippon in eastern Japan. In this study, specific PCR for the Asia lineage identified 11 positives in 822 host-seeking Ixodes persulcatus ticks, a principal vector for many tick-borne disease agents. Gene sequences of three isolates obtained from DNA in salivary glands of female ticks were identical to each other and to those in C. nippon We also demonstrate the coinfection of B. divergens Asia lineage with Babesia microti U.S. lineage in a tick salivary gland and, furthermore, isolated the latter in a hamster. These results suggest that I. persulcatus is the principal vector for B. divergens as well as for B. microti , and both parasites may be occasionally cotransmitted by I. persulcatus This report will be important for public health, since infection may occur through transfusion. Copyright © 2018 American Society for Microbiology.

Experimental Transmission of Karshi (Mammalian Tick-Borne Flavivirus Group) Virus by Ornithodoros Ticks >2,900 Days after Initial Virus Exposure Supports the Role of Soft Ticks as a Long-Term Maintenance Mechanism for Certain Flaviviruses.

PubMed

Turell, Michael J

2015-01-01

Members of the mammalian tick-borne flavivirus group, including tick-borne encephalitis virus, are responsible for at least 10,000 clinical cases of tick-borne encephalitis each year. To attempt to explain the long-term maintenance of members of this group, we followed Ornithodoros parkeri, O. sonrai, and O. tartakovskyi for >2,900 days after they had been exposed to Karshi virus, a member of the mammalian tick-borne flavivirus group. Ticks were exposed to Karshi virus either by allowing them to feed on viremic suckling mice or by intracoelomic inoculation. The ticks were then allowed to feed individually on suckling mice after various periods of extrinsic incubation to determine their ability to transmit virus by bite and to determine how long the ticks would remain infectious. The ticks remained efficient vectors of Karshi virus, even when tested >2,900 d after their initial exposure to virus, including those ticks exposed to Karshi virus either orally or by inoculation. Ornithodoros spp. ticks were able to transmit Karshi virus for >2,900 days (nearly 8 years) after a single exposure to a viremic mouse. Therefore, these ticks may serve as a long-term maintenance mechanism for Karshi virus and potentially other members of the mammalian tick-borne flavivirus group.

The Evolving Medical and Veterinary Importance of the Gulf Coast tick (Acari: Ixodidae).

PubMed

Paddock, Christopher D; Goddard, Jerome

2015-03-01

Amblyomma maculatum Koch (the Gulf Coast tick) is a three-host, ixodid tick that is distributed throughout much of the southeastern and south-central United States, as well as several countries throughout Central and South America. A considerable amount of scientific literature followed the original description of A. maculatum in 1844; nonetheless, the Gulf Coast tick was not recognized as a vector of any known pathogen of animals or humans for >150 years. It is now identified as the principal vector of Hepatozoon americanum, the agent responsible for American canine hepatozoonosis, and Rickettsia parkeri, the cause of an emerging, eschar-associated spotted fever group rickettsiosis identified throughout much of the Western Hemisphere. Coincident with these discoveries has been recognition that the geographical distribution of A. maculatum in the United States is far more extensive than described 70 yr ago, supporting the idea that range and abundance of certain tick species, particularly those with diverse host preferences, are not fixed in time or space, and may change over relatively short intervals. Renewed interest in the Gulf Coast tick reinforces the notion that the perceived importance of a particular tick species to human or animal health can be relatively fluid, and may shift dramatically with changes in the distribution and abundance of the arthropod, its vertebrate hosts, or the microbial agents that transit among these organisms. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

Seasonal dynamics of ixodid ticks on wild rabbits Oryctolagus cuniculus (Leporidae) from Central Spain.

PubMed

González, J; Valcárcel, F; Pérez-Sánchez, J L; Tercero-Jaime, J M; Olmeda, A S

2016-11-01

Rabbit Hemorrhagic Disease and Myxomatosis caused a decline in the rabbit population in the second half of the last century. Despite some recovery, the risk of vector-borne disease is present and thus the importance of controlling vector populations. In the current study, we describe the ixodid tick fauna in wild rabbit in a natural reserve in Ciudad Real (Central Spain) during the course of two 3-year periods (2007-2009 and 2012-2014). Of all the ticks collected on average 72.5 % were larvae, 24.4 % nymphs and 3.1 % adults, although the percentage varied monthly. Seven tick species were identified: Hyalomma lusitanicum Koch (Parasitic indicator [PI] = number of ticks per examined rabbit = 96.47), Rhipicephalus pusillus Gil Collado (PI = 47.37), Haemaphysalis hispanica Gil Collado (PI = 12.15), Ixodes ventalloi Gil Collado (PI = 0.65), R. bursa Canestrini and Fanzago (PI = 0.18), R. sanguineus Latreille (PI = 0.11), Dermacentor marginatus Sulzer (PI = 0.01). In spring and summer, most abundant were larvae of H. lusitanicum, followed by immature stages of R. pusillus and Ha. hispanica. In autumn, the main tick species were nymphs of I. ventalloi whereas in winter adults of Ha. hispanica were more numerous. Rhipicephalus pusillus was present all year long, although not always in high percentage. PI of other species (R. bursa, R. sanguineus and D. marginatus) were too low to be representative. The seasonal dynamics of ticks on wild rabbit defined in this study could be useful to design species-specific control strategies.

Population structure of the lyme borreliosis spirochete Borrelia burgdorferi in the western black-legged tick (Ixodes pacificus) in Northern California.

PubMed

Girard, Yvette A; Travinsky, Bridgit; Schotthoefer, Anna; Fedorova, Natalia; Eisen, Rebecca J; Eisen, Lars; Barbour, Alan G; Lane, Robert S

2009-11-01

Factors potentially contributing to the lower incidence of Lyme borreliosis (LB) in the far-western than in the northeastern United States include tick host-seeking behavior resulting in fewer human tick encounters, lower densities of Borrelia burgdorferi-infected vector ticks in peridomestic environments, and genetic variation among B. burgdorferi spirochetes to which humans are exposed. We determined the population structure of B. burgdorferi in over 200 infected nymphs of the primary bridging vector to humans, Ixodes pacificus, collected in Mendocino County, CA. This was accomplished by sequence typing the spirochete lipoprotein ospC and the 16S-23S rRNA intergenic spacer (IGS). Thirteen ospC alleles belonging to 12 genotypes were found in California, and the two most abundant, ospC genotypes H3 and E3, have not been detected in ticks in the Northeast. The most prevalent ospC and IGS biallelic profile in the population, found in about 22% of ticks, was a new B. burgdorferi strain defined by ospC genotype H3. Eight of the most common ospC genotypes in the northeastern United States, including genotypes I and K that are associated with disseminated human infections, were absent in Mendocino County nymphs. ospC H3 was associated with hardwood-dominated habitats where western gray squirrels, the reservoir host, are commonly infected with LB spirochetes. The differences in B. burgdorferi population structure in California ticks compared to the Northeast emphasize the need for a greater understanding of the genetic diversity of spirochetes infecting California LB patients.

Comparative analysis of storage conditions and homogenization methods for tick and flea species for identification by MALDI-TOF MS.

PubMed

Nebbak, A; El Hamzaoui, B; Berenger, J-M; Bitam, I; Raoult, D; Almeras, L; Parola, P

2017-12-01

Ticks and fleas are vectors for numerous human and animal pathogens. Controlling them, which is important in combating such diseases, requires accurate identification, to distinguish between vector and non-vector species. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was applied to the rapid identification of arthropods. The growth of this promising tool, however, requires guidelines to be established. To this end, standardization protocols were applied to species of Rhipicephalus sanguineus (Ixodida: Ixodidae) Latreille and Ctenocephalides felis felis (Siphonaptera: Pulicidae) Bouché, including the automation of sample homogenization using two homogenizer devices, and varied sample preservation modes for a period of 1-6 months. The MS spectra were then compared with those obtained from manual pestle grinding, the standard homogenization method. Both automated methods generated intense, reproducible MS spectra from fresh specimens. Frozen storage methods appeared to represent the best preservation mode, for up to 6 months, while storage in ethanol is also possible, with some caveats for tick specimens. Carnoy's buffer, however, was shown to be less compatible with MS analysis for the purpose of identifying ticks or fleas. These standard protocols for MALDI-TOF MS arthropod identification should be complemented by additional MS spectrum quality controls, to generalize their use in monitoring arthropods of medical interest. © 2017 The Royal Entomological Society.

Profiling of proteolytic enzymes in the gut of the tick Ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases

PubMed Central

Sojka, Daniel; Franta, Zdeněk; Horn, Martin; Hajdušek, Ondřej; Caffrey, Conor R; Mareš, Michael; Kopáček, Petr

2008-01-01

Background Ticks are vectors for a variety of viral, bacterial and parasitic diseases in human and domestic animals. To survive and reproduce ticks feed on host blood, yet our understanding of the intestinal proteolytic machinery used to derive absorbable nutrients from the blood meal is poor. Intestinal digestive processes are limiting factors for pathogen transmission since the tick gut presents the primary site of infection. Moreover, digestive enzymes may find practical application as anti-tick vaccine targets. Results Using the hard tick, Ixodes ricinus, we performed a functional activity scan of the peptidase complement in gut tissue extracts that demonstrated the presence of five types of peptidases of the cysteine and aspartic classes. We followed up with genetic screens of gut-derived cDNA to identify and clone genes encoding the cysteine peptidases cathepsins B, L and C, an asparaginyl endopeptidase (legumain), and the aspartic peptidase, cathepsin D. By RT-PCR, expression of asparaginyl endopeptidase and cathepsins B and D was restricted to gut tissue and to those developmental stages feeding on blood. Conclusion Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner. Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms. Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases. PMID:18348719

Effectiveness of permethrin-treated clothing to prevent tick exposure in foresters in the central Appalachian region of the USA.

PubMed

L Richards, Stephanie; G Balanay, Jo Anne; W Harris, Jonathan

2015-01-01

Outdoor workers are at risk from mosquito and tick bites and the extent to which exposures are linked to vector-borne disease is not understood. This pilot study characterizes for ester exposure to mosquitoes and ticks, and assesses effectiveness of permethrin-treated clothing for prevention of tick bites. Foresters (N = 34) from Kentucky, North Carolina, Ohio, Tennessee, Virginia, and West Virginia were placed into treatment (permethrin-treated clothing) or control (untreated clothing) groups. Foresters completed questionnaires about work-related tick/mosquito exposure and 454 ticks were collected/identified from May to June 2013. A time-weighted analysis based on information submitted by foresters about time working outdoors showed that control participants received a lower rate of tick exposure (0.15 tick bites/hour; 13 bites/person) compared to treatment participants (0.27 bites/hour; 21 bites/person). However, more control participants (85 %) received at least one tick bite compared to treatment participants (52 %). Outdoor workers should be aware of available protective measures, such as permethrin-treated clothing, that may mitigate occupational risks.

Quantitative Differences in Salivary Pathogen Load during Tick Transmission Underlie Strain-Specific Variation in Transmission Efficiency of Anaplasma marginale

USDA-ARS?s Scientific Manuscript database

The relative fitness of arthropod-borne pathogens within the vector can be a major determinant of pathogen prevalence within the mammalian host population. Strains of the tick-borne rickettsia Anaplasma marginale differ markedly in transmission efficiency with consequent impact on pathogen strain st...

[Canine visceral leishmaniasis in northeast Brazil: epidemiological aspects].

PubMed

Silva, O A; Silva, P B; Silva, O V; Braga, G M; Albuquerque Júnior, A; Queiros Neto, V; Rocha, M E; Silva, E F

2007-02-01

In a rural area of Northeast Brazil, the relatively high serological infection by Leishmania in dogs, the lack of classical vector Lutzomyia longipalpis and of American Visceral Leishmaniasis cases in human beings and the observation of Leishmania in ticks collected in infected dogs suggest that ticks may be responsible for the transmission between dogs.

Transcriptome database derived from the Texas Deutsch outbreak strain population of the cattle tick, Rhipicephalus (Boophilus) microplus

USDA-ARS?s Scientific Manuscript database

The Southern cattle tick, Rhipicephalus (Boophilus) microplus, vectors Babesia bovis and B. bigemina, which are the protozoans causing cattle fever, a disease that is responsible for significant production losses to cattle producers in much of Africa, Central and South America, and Australia. We ini...

Range-wide genetic analysis of Dermacentor variabilis and its Francisella-like endosymbionts demonstrates phylogeographic concordance between both taxa

USDA-ARS?s Scientific Manuscript database

Background: The American dog tick, Dermacentor variabilis, is an important vector of pathogens to humans, wildlife, and domestic animals in North America. Although this tick is widely distributed in the US and Canada, knowledge of its range-wide phylogeographic patterns remains incomplete. Methods:...

In vitro repellency of DEET against the ticks Rhipicephalus sanguineus sensu lato and Amblyomma sculptum

USDA-ARS?s Scientific Manuscript database

Rhipicephalus sanguineus sensu lato and Amblyomma sculptum can parasite humans and domestic animals and are vectors of pathogens, including zoonoses. Repellents are an important tool of tick control. This study aimed to compare the efficacy of N,N-diethyl- 3-methylbenzamide (DEET), a standard repell...

Rapid Identification of Vector-Borne Flaviviruses by Mass Spectrometry

DTIC Science & Technology

2010-02-01

Langat LGTV TP-21 Tick/Malaysia/1956 EU790644 Omsk hemorrhagic fever virus OHFV Belangul Human/1947 NR Powassan POWV LB Human/Canada/1958 L06436 a Tick...diagnostic plat- forms, the detection of viruses such as Tembusu and Langat viruses demonstrates the assay’s ability to identify less known flaviviruses

Partial Characterization of Tick-Borne Encephalitis Virus Isolates from Ticks of Southern Ukraine.

PubMed

Yurchenko, Oksana O; Dubina, Dmytro O; Vynograd, Nataliya O; Gonzalez, Jean-Paul

2017-08-01

Tick-borne encephalitis (TBE) is the most common tick-borne viral infection in Eurasia; thousands of human cases are annually reported from several European countries. Several tick species are vectors of the tick-borne encephalitis virus (TBEV), while TBE appears to be spreading from the Eurasian continent westward to Europe. Fifteen study sites were chosen from five territories of southern Ukraine, including Odessa, Mykolaiv, Kherson Oblast, the Autonomous Republic of Crimea, and Sevastopol. Tick collection was performed in spring season of three consecutive years (1988-1990) using either flagging technique or direct collection of specimens feeding on cattle. A total of 15,243 tick imagoes and nymphs were collected from nine species, including Dermacentor marginatus, D. reticulatus, Haemaphysalis parva, H. punctata, Hyalomma marginatum, Ixodes ricinus, Rhipicephalus bursa, R. rossicus, and R. sanguineus, pooled in 282 monospecific samples. Supernatant of grinded pool was used for inoculation to suckling mice for virus isolation. Eight TBEV isolates were identified from ticks among six study sites. Ticks showed a minimum infection rate from 0.11% to 0.81%. Phylogenetic analysis of the envelope (E) protein gene of seven isolates, assigned all to the European subtype (TBEV-Eu) showing a maximum identity of 97.17% to the "Pan" TBEV-Eu reference strain. Compared to 104 TBEV-Eu isolates they clustered within the same clade as the Pan reference strain and distinguished from other TBEV-Eu isolates. Amino acid sequence analysis of the South Ukrainian TBEV-Eu isolates revealed the presence of four amino acid substitutions 67 (N), 266 (R), 306 (V), and 407 (R), in the ectodomains II and III and in the stem-anchor region of the E protein gene. This study confirmed TBEV-Eu subtype distribution in the southern region of Ukraine, which eventually overlaps with TBEV-FE (Far Eastern subtype) and TBEV-Sib (Siberian subtype) domains, showing the heterogeneity of TBEV circulating in Ukraine.

Partial Characterization of Tick-Borne Encephalitis Virus Isolates from Ticks of Southern Ukraine

PubMed Central

Dubina, Dmytro O.; Vynograd, Nataliya O.; Gonzalez, Jean-Paul

2017-01-01

Abstract Tick-borne encephalitis (TBE) is the most common tick-borne viral infection in Eurasia; thousands of human cases are annually reported from several European countries. Several tick species are vectors of the tick-borne encephalitis virus (TBEV), while TBE appears to be spreading from the Eurasian continent westward to Europe. Fifteen study sites were chosen from five territories of southern Ukraine, including Odessa, Mykolaiv, Kherson Oblast, the Autonomous Republic of Crimea, and Sevastopol. Tick collection was performed in spring season of three consecutive years (1988–1990) using either flagging technique or direct collection of specimens feeding on cattle. A total of 15,243 tick imagoes and nymphs were collected from nine species, including Dermacentor marginatus, D. reticulatus, Haemaphysalis parva, H. punctata, Hyalomma marginatum, Ixodes ricinus, Rhipicephalus bursa, R. rossicus, and R. sanguineus, pooled in 282 monospecific samples. Supernatant of grinded pool was used for inoculation to suckling mice for virus isolation. Eight TBEV isolates were identified from ticks among six study sites. Ticks showed a minimum infection rate from 0.11% to 0.81%. Phylogenetic analysis of the envelope (E) protein gene of seven isolates, assigned all to the European subtype (TBEV-Eu) showing a maximum identity of 97.17% to the “Pan” TBEV-Eu reference strain. Compared to 104 TBEV-Eu isolates they clustered within the same clade as the Pan reference strain and distinguished from other TBEV-Eu isolates. Amino acid sequence analysis of the South Ukrainian TBEV-Eu isolates revealed the presence of four amino acid substitutions 67 (N), 266 (R), 306 (V), and 407 (R), in the ectodomains II and III and in the stem-anchor region of the E protein gene. This study confirmed TBEV-Eu subtype distribution in the southern region of Ukraine, which eventually overlaps with TBEV-FE (Far Eastern subtype) and TBEV-Sib (Siberian subtype) domains, showing the heterogeneity of TBEV circulating in Ukraine. PMID:28654319

Ethnoknowledge of Bukusu community on livestock tick prevention and control in Bungoma district, western Kenya.

PubMed

Wanzala, Wycliffe; Takken, Willem; Mukabana, Wolfgang R; Pala, Achola O; Hassanali, Ahmed

2012-03-27

To date, nomadic communities in Africa have been the primary focus of ethnoveterinary research. The Bukusu of western Kenya have an interesting history, with nomadic lifestyle in the past before settling down to either arable or mixed arable/pastoral farming systems. Their collective and accumulative ethnoveterinary knowledge is likely to be just as rich and worth documenting. The aim of the present study was to document indigenous knowledge of the Bukusu on the effect of livestock ticks and ethnopractices associated with their management. It was envisaged that this would provide a basis for further research on the efficacy of these practices that could also lead to the discovery of useful tick-control agents. Non-alienating, dialogic, participatory action research (PAR) and participatory rural appraisal (PRA) approaches involving 272 women and men aged between 18 and 118 years from the Bukusu community were used. Ticks are traditionally classified and identified by colour, size, host range, on-host feeding sites, and habitat preference. Tick-associated problems recognised include kamabumba (local reference to East Coast fever, Anaplasmosis or Heartwater diseases transmitted by different species of livestock ticks) and general poor performance of livestock. Traditional methods of controlling ticks include handpicking, on-host use of ethnobotanical suspensions (prepared from one or more of over 150 documented plants) to kill the ticks and prevent re-infestation, fumigation of infested cattle with smoke derived from burning ethnobotanical products, burning pastures, rotational grazing ethnopractices, and livestock quarantine. The study confirms that the Bukusu have preserved rich ethnoveterinary knowledge and practices. It provides some groundwork for elucidating the efficacy of some of these ethnopractices in protecting livestock from tick disease vectors, particularly those involving the use of ethnobotanicals, which may lead to the discovery of useful ant-tick agents. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Transfected Babesia bovis Expressing a Tick GST as a Live Vector Vaccine

PubMed Central

Oldiges, Daiane P.; Laughery, Jacob M.; Tagliari, Nelson Junior; Leite Filho, Ronaldo Viana; Davis, William C.; da Silva Vaz, Itabajara; Termignoni, Carlos; Knowles, Donald P.; Suarez, Carlos E.

2016-01-01

The Rhipicephalus microplus tick is a notorious blood-feeding ectoparasite of livestock, especially cattle, responsible for massive losses in animal production. It is the main vector for transmission of pathogenic bacteria and parasites, including Babesia bovis, an intraerythrocytic apicomplexan protozoan parasite responsible for bovine Babesiosis. This study describes the development and testing of a live B. bovis vaccine expressing the protective tick antigen glutathione-S-transferase from Haemaphysalis longicornis (HlGST). The B. bovis S74-T3B parasites were electroporated with a plasmid containing the bidirectional Ef-1α (elongation factor 1 alpha) promoter of B. bovis controlling expression of two independent genes, the selectable marker GFP-BSD (green fluorescent protein–blasticidin deaminase), and HlGST fused to the MSA-1 (merozoite surface antigen 1) signal peptide from B. bovis. Electroporation followed by blasticidin selection resulted in the emergence of a mixed B. bovis transfected line (termed HlGST) in in vitro cultures, containing parasites with distinct patterns of insertion of both exogenous genes, either in or outside the Ef-1α locus. A B. bovis clonal line termed HlGST-Cln expressing intracellular GFP and HlGST in the surface of merozoites was then derived from the mixed parasite line HlGST using a fluorescent activated cell sorter. Two independent calf immunization trials were performed via intravenous inoculation of the HlGST-Cln and a previously described control consisting of an irrelevant transfected clonal line of B. bovis designated GFP-Cln. The control GFP-Cln line contains a copy of the GFP-BSD gene inserted into the Ef-1α locus of B. bovis in an identical fashion as the HIGST-Cln parasites. All animals inoculated with the HlGST-Cln and GFP-Cln transfected parasites developed mild babesiosis. Tick egg fertility and fully engorged female tick weight was reduced significantly in R. microplus feeding on HlGST-Cln-immunized calves. Collectively, these data show the efficacy of a transfected HlGST-Cln B. bovis parasite to induce detectable anti-glutathione-S-transferase antibodies and a reduction in tick size and fecundity of R. microplus feeding in experimentally inoculated animals. PMID:27911903

Ecology and Epidemiology of Lyme Borreliosis.

PubMed

Schotthoefer, Anna M; Frost, Holly M

2015-12-01

Lyme borreliosis is a zoonotic, tick-borne disease that infects humans worldwide. The disease is currently recognized as the most common vector-borne disease in Europe and North America. Disease is caused by several genospecies of the Borrelia burgdorferi sensu lato complex. Humans are at high risk of infection in regions where highly competent reservoirs are the primary hosts for the subadult stages of the tick, in contrast to regions where less competent or refractory animals feed ticks. Human infections are also most frequently associated with spring and summer months when the nymph stage of the tick is active. Copyright © 2015 Elsevier Inc. All rights reserved.

Bridging of cryptic Borrelia cycles in European songbirds.

PubMed

Heylen, Dieter; Krawczyk, Aleksandra; Lopes de Carvalho, Isabel; Núncio, Maria Sofia; Sprong, Hein; Norte, Ana Cláudia

2017-05-01

The principal European vector for Borrelia burgdorferi s.l., the causative agents of Lyme disease, is the host-generalist tick Ixodes ricinus. Almost all terrestrial host-specialist ticks have been supposed not to contribute to the terrestrial Borrelia transmission cycles. Through an experiment with blackbirds, we show successful transmission by the widespread I. frontalis, an abundant bird-specialized tick that infests a broad range of songbirds. In the first phase of the experiment, we obtained Borrelia-infected I. frontalis (infection rate: 19%) and I. ricinus (17%) nymphs by exposing larvae to wild blackbirds that carried several genospecies (Borrelia turdi, B. valaisiana, B. burgdorferi s.s.). In the second phase, pathogen-free blackbirds were exposed to these infected nymphs. Both tick species were able to infect the birds, as indicated by the analysis of xenodiagnostic I. ricinus larvae which provided evidence for both co-feeding and systemic transmission (infection rates: 10%-60%). Ixodes frontalis was shown to transmit B. turdi spirochetes, while I. ricinus transmitted both B. turdi and B. valaisiana. Neither species transmitted B. burgdorferi s.s. European enzootic cycles of Borrelia between songbirds and their ornithophilic ticks do exist, with I. ricinus potentially acting as a bridging vector towards mammals, including man. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Multi-Scale Clustering of Lyme Disease Risk at the Expanding Leading Edge of the Range of Ixodes scapularis in Canada.

PubMed

Ripoche, Marion; Lindsay, Leslie Robbin; Ludwig, Antoinette; Ogden, Nicholas H; Thivierge, Karine; Leighton, Patrick A

2018-03-27

Since its detection in Canada in the early 1990s, Ixodes scapularis , the primary tick vector of Lyme disease in eastern North America, has continued to expand northward. Estimates of the tick's broad-scale distribution are useful for tracking the extent of the Lyme disease risk zone; however, tick distribution may vary widely within this zone. Here, we investigated I. scapularis nymph distribution at three spatial scales across the Lyme disease emergence zone in southern Quebec, Canada. We collected ticks and compared the nymph densities among different woodlands and different plots and transects within the same woodland. Hot spot analysis highlighted significant nymph clustering at each spatial scale. In regression models, nymph abundance was associated with litter depth, humidity, and elevation, which contribute to a suitable habitat for ticks, but also with the distance from the trail and the type of trail, which could be linked to host distribution and human disturbance. Accounting for this heterogeneous nymph distribution at a fine spatial scale could help improve Lyme disease management strategies but also help people to understand the risk variation around them and to adopt appropriate behaviors, such as staying on the trail in infested parks to limit their exposure to the vector and associated pathogens.

Microtomography of the Baltic amber tick Ixodes succineus reveals affinities with the modern Asian disease vector Ixodes ovatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunlop, Jason A.; Apanaskevich, Dmitry A.; Lehmann, Jens

Background: Fossil ticks are extremely rare, whereby Ixodes succineus Weidner, 1964 from Eocene (ca. 44–49 Ma) Baltic amber is one of the oldest examples of a living hard tick genus (Ixodida: Ixodidae). Previous work suggested it was most closely related to the modern and widespread European sheep tick Ixodes ricinus (Linneaus, 1758). Results: Restudy using phase contrast synchrotron x-ray tomography yielded images of exceptional quality. These confirm the fossil’s referral to Ixodes Latreille, 1795, but the characters resolved here suggest instead affinities with the Asian subgenus Partipalpiger Hoogstraal et al., 1973 and its single living (and medically significant) species Ixodesmore » ovatus Neumann, 1899. We redescribe the amber fossil here as Ixodes (Partipalpiger) succineus. Conclusions: Our data suggest that Ixodes ricinus is unlikely to be directly derived from Weidner’s amber species, but instead reveals that the Partipalpiger lineage was originally more widely distributed across the northern hemisphere. The closeness of Ixodes (P.) succineus to a living vector of a wide range of pathogens offers the potential to correlate its spatial and temporal position (northern Europe, nearly 50 million years ago) with the estimated origination dates of various tick-borne diseases.« less

Increased Relative Risk of Tick-Borne Encephalitis in Warmer Weather.

PubMed

Daniel, Milan; Danielová, Vlasta; Fialová, Alena; Malý, Marek; Kříž, Bohumír; Nuttall, Patricia A

2018-01-01

Tick-borne encephalitis (TBE) is a serious acute neuroinfection of humans caused by a tick-borne flavivirus. The disease is typically seasonal, linked to the host-seeking activity of Ixodes ricinus (predominantly nymphs), the principal European tick vector species. To address the need for accurate risk predictions of contracting TBE, data on 4,044 TBE cases reported in the Czech Republic during 2001-2006 were compared with questing activity of I. ricinus nymphs monitored weekly at a defined location for the same 6-year period. A time shift of 21 days between infected tick bite and recorded disease onset provided the optimal model for comparing the number of cases of TBE with numbers of questing nymphs. Mean annual distribution of TBE cases and tick counts showed a similar bimodal distribution. Significantly, the ratio of TBE cases to questing nymphs was highest in the summer-autumn period even though the number of questing nymphs peaked in the spring-summer period. However, this pattern changed during a period of extreme meteorological events of flooding and abnormally high temperatures, indicating that changes in climate affect the incidence of TBE. Previous studies failed to link human behavior with changes in incidence of TBE but showed extrinsic temperature impacts arbovirus replication. Hence, we hypothesize the apparent discrepancy between peak nymphal tick activity and greatest risk of contracting TBE is due to the effect of temperature on virus replication in the tick vector. Relative proportions of questing nymphs and the numbers of weeks in which they were found were greater in summer-autumn compared with spring-summer at near-ground temperatures >5°C and at standard day and weekly average temperatures of >15°C. Thus, during the summer-autumn period, the virus dose in infected tick bites is likely greater owing to increased virus replication at higher microclimatic temperatures, consequently increasing the relative risk of contracting TBE per summer-autumn tick bite. The data support the use of weather-based forecasts of tick attack risk (based on daytime ambient temperature) supplemented with weekly average temperature (as a proxy for virus replication) to provide much-needed real-time forecasts of TBE risk.

Mitochondrial phylogeography and population structure of the cattle tick Rhipicephalus appendiculatus in the African Great Lakes region.

PubMed

Amzati, Gaston S; Pelle, Roger; Muhigwa, Jean-Berckmans B; Kanduma, Esther G; Djikeng, Appolinaire; Madder, Maxime; Kirschvink, Nathalie; Marcotty, Tanguy

2018-05-31

The ixodid tick Rhipicephalus appendiculatus is the main vector of Theileria parva, wich causes the highly fatal cattle disease East Coast fever (ECF) in sub-Saharan Africa. Rhipicephalus appendiculatus populations differ in their ecology, diapause behaviour and vector competence. Thus, their expansion in new areas may change the genetic structure and consequently affect the vector-pathogen system and disease outcomes. In this study we investigated the genetic distribution of R. appendiculatus across agro-ecological zones (AEZs) in the African Great Lakes region to better understand the epidemiology of ECF and elucidate R. appendiculatus evolutionary history and biogeographical colonization in Africa. Sequencing was performed on two mitochondrial genes (cox1 and 12S rRNA) of 218 ticks collected from cattle across six AEZs along an altitudinal gradient in the Democratic Republic of Congo, Rwanda, Burundi and Tanzania. Phylogenetic relationships between tick populations were determined and evolutionary population dynamics models were assessed by mismach distribution. Population genetic analysis yielded 22 cox1 and 9 12S haplotypes in a total of 209 and 126 nucleotide sequences, respectively. Phylogenetic algorithms grouped these haplotypes for both genes into two major clades (lineages A and B). We observed significant genetic variation segregating the two lineages and low structure among populations with high degree of migration. The observed high gene flow indicates population admixture between AEZs. However, reduced number of migrants was observed between lowlands and highlands. Mismatch analysis detected a signature of rapid demographic and range expansion of lineage A. The star-like pattern of isolated and published haplotypes indicates that the two lineages evolve independently and have been subjected to expansion across Africa. Two sympatric R. appendiculatus lineages occur in the Great Lakes region. Lineage A, the most diverse and ubiquitous, has experienced rapid population growth and range expansion in all AEZs probably through cattle movement, whereas lineage B, the less abundant, has probably established a founder population from recent colonization events and its occurrence decreases with altitude. These two lineages are sympatric in central and eastern Africa and allopatric in southern Africa. The observed colonization pattern may strongly affect the transmission system and may explain ECF endemic instability in the tick distribution fringes.

Prevalence of tick-borne encephalitis virus in Ixodes ricinus ticks in northern Europe with particular reference to Southern Sweden.

PubMed

Pettersson, John H-O; Golovljova, Irina; Vene, Sirkka; Jaenson, Thomas G T

2014-03-11

In northern Europe, the tick-borne encephalitis virus (TBEV) of the European subtype is usually transmitted to humans by the common tick Ixodes ricinus. The aims of the present study are (i) to obtain up-to-date information on the TBEV prevalence in host-seeking I. ricinus in southern and central Sweden; (ii) to compile and review all relevant published records on the prevalence of TBEV in ticks in northern Europe; and (iii) to analyse and try to explain how the TBE virus can be maintained in natural foci despite an apparently low TBEV infection prevalence in the vector population. To estimate the mean minimum infection rate (MIR) of TBEV in I. ricinus in northern Europe (i.e. Denmark, Norway, Sweden and Finland) we reviewed all published TBEV prevalence data for host-seeking I. ricinus collected during 1958-2011. Moreover, we collected 2,074 nymphs and 906 adults of I. ricinus from 29 localities in Sweden during 2008. These ticks were screened for TBEV by RT-PCR. The MIR for TBEV in nymphal and adult I. ricinus was 0.28% for northern Europe and 0.23% for southern Sweden. The infection prevalence of TBEV was significantly lower in nymphs (0.10%) than in adult ticks (0.55%). At a well-known TBEV-endemic locality, Torö island south-east of Stockholm, the TBEV prevalence (MIR) was 0.51% in nymphs and 4.48% in adults of I. ricinus. If the ratio of nymphs to adult ticks in the TBEV-analysed sample differs from that in the I. ricinus population in the field, the MIR obtained will not necessarily reflect the TBEV prevalence in the field. The relatively low TBEV prevalence in the potential vector population recorded in most studies may partly be due to: (i) inclusion of uninfected ticks from the 'uninfected areas' surrounding the TBEV endemic foci; (ii) inclusion of an unrepresentative, too large proportion of immature ticks, compared to adult ticks, in the analysed tick pools; and (iii) shortcomings in the laboratory techniques used to detect the virus that may be present in a very low concentration or undetectable state in ticks which have not recently fed.

Features of Brazilian spotted fever in two different endemic areas in Brazil.

PubMed

Angerami, Rodrigo N; Câmara, Milena; Pacola, Márcia R; Rezende, Regina C M; Duarte, Raquel M R; Nascimento, Elvira M M; Colombo, Silvia; Santos, Fabiana C P; Leite, Ruth M; Katz, Gizelda; Silva, Luiz J

2012-12-01

Brazilian spotted fever (BSF) caused by Rickettsia rickettsii is the most important rickettsiosis and the only reportable tick-borne disease in Brazil. In Brazil, the hard tick Amblyomma cajennense is the most important BSF vector; however, in São Paulo State, A. aureolatum was also recognized as a vector species in remaining Atlantic forest areas near the metropolitan area of São Paulo city. We analyzed clinical and epidemiological features of BSF cases from two distinct areas where A. cajennense (Area 1) and A. aureolatum (Area 2) are the incriminated vectors. The clinical features demonstrate the same severity pattern of BSF in both endemic areas. Differences in seasonality, patient characteristics (median age and gender), and epidemiological risk factors (animals host contact and vegetation characteristics) were observed and possibly could be attributed to the characteristics of each vector and their typical biological cycle (hosts and environment). Copyright © 2012 Elsevier GmbH. All rights reserved.

Using Landscape Analysis to Test Hypotheses about Drivers of Tick Abundance and Infection Prevalence with Borrelia burgdorferi.

PubMed

Ferrell, A Michelle; Brinkerhoff, R Jory

2018-04-12

Patterns of vector-borne disease risk are changing globally in space and time and elevated disease risk of vector-borne infection can be driven by anthropogenic modification of the environment. Incidence of Lyme disease, caused by the bacterium Borrelia burgdorferi sensu stricto, has risen in a number of locations in North America and this increase may be driven by spatially or numerically expanding populations of the primary tick vector, Ixodes scapularis . We used a model selection approach to identify habitat fragmentation and land-use/land cover variables to test the hypothesis that the amount and configuration of forest cover at spatial scales relevant to deer, the primary hosts of adult ticks, would be the predominant determinants of tick abundance. We expected that land cover heterogeneity and amount of forest edge, a habitat thought to facilitate deer foraging and survival, would be the strongest driver of tick density and that larger spatial scales (5-10 km) would be more important than smaller scales (1 km). We generated metrics of deciduous and mixed forest fragmentation using Fragstats 4.4 implemented in ArcMap 10.3 and found, after adjusting for multicollinearity, that total forest edge within a 5 km buffer had a significant negative effect on tick density and that the proportion of forested land cover within a 10 km buffer was positively associated with density of I. scapularis nymphs. None of the 1 km fragmentation metrics were found to significantly improve the fit of the model. Elevation, previously associated with increased density of I. scapularis nymphs in Virginia, while significantly predictive in univariate analysis, was not an important driver of nymph density relative to fragmentation metrics. Our results suggest that amount of forest cover (i.e., lack of fragmentation) is the most important driver of I. scapularis density in our study system.

Development of a loop-mediated isothermal amplification (LAMP) assay for rapid screening of ticks and fleas for spotted fever group rickettsia

PubMed Central

Martin, Jaclyn; Carrillo, Yisel; Talley, Justin L.; Ochoa-Corona, Francisco M.

2018-01-01

Background The importance of tick and flea-borne rickettsia infections is increasingly recognized worldwide. While increased focus has shifted in recent years to the development of point-of-care diagnostics for various vector-borne diseases in humans and animals, little research effort has been devoted to their integration into vector surveillance and control programs, particularly in resource-challenged countries. One technology which may be helpful for large scale vector surveillance initiatives is loop-mediated isothermal amplification (LAMP). The aim of this study was to develop a LAMP assay to detect spotted fever group (SFG) rickettsia DNA from field-collected ticks and fleas and compare with published end-point PCR results. Methodology/Principal findings A Spotted Fever Group rickettsia-specific loop-mediated isothermal amplification (SFGR-LAMP) assay was developed using primers based on a region of the R. rickettsii 17kDa protein gene. The sensitivity, specificity, and reproducibility of the assay were evaluated. The assay was then compared with the results of end-point PCR assays for pooled tick and flea samples obtained from field-based surveillance studies. The sensitivity of the SFGR-LAMP assay was 0.00001 ng/μl (25μl volume) which was 10 times more sensitive than the 17kDa protein gene end-point PCR used as the reference method. The assay only recognized gDNA from SFG and transitional group (TRG) rickettsia species tested but did not detect gDNA from typhus group (TG) rickettsia species or closely or distantly related bacterial species. The SFGR-LAMP assay detected the same positives from a set of pooled tick and flea samples detected by end-point PCR in addition to two pooled flea samples not detected by end-point PCR. Conclusions/significance To our knowledge, this is the first study to develop a functional LAMP assay to initially screen for SFG and TRG rickettsia pathogens in field-collected ticks and fleas. With a high sensitivity and specificity, the results indicate the potential use as a field-based surveillance tool for tick and flea-borne rickettsial pathogens in resource-challenged countries. PMID:29390021

Development of a loop-mediated isothermal amplification (LAMP) assay for rapid screening of ticks and fleas for spotted fever group rickettsia.

PubMed

Noden, Bruce H; Martin, Jaclyn; Carrillo, Yisel; Talley, Justin L; Ochoa-Corona, Francisco M

2018-01-01

The importance of tick and flea-borne rickettsia infections is increasingly recognized worldwide. While increased focus has shifted in recent years to the development of point-of-care diagnostics for various vector-borne diseases in humans and animals, little research effort has been devoted to their integration into vector surveillance and control programs, particularly in resource-challenged countries. One technology which may be helpful for large scale vector surveillance initiatives is loop-mediated isothermal amplification (LAMP). The aim of this study was to develop a LAMP assay to detect spotted fever group (SFG) rickettsia DNA from field-collected ticks and fleas and compare with published end-point PCR results. A Spotted Fever Group rickettsia-specific loop-mediated isothermal amplification (SFGR-LAMP) assay was developed using primers based on a region of the R. rickettsii 17kDa protein gene. The sensitivity, specificity, and reproducibility of the assay were evaluated. The assay was then compared with the results of end-point PCR assays for pooled tick and flea samples obtained from field-based surveillance studies. The sensitivity of the SFGR-LAMP assay was 0.00001 ng/μl (25μl volume) which was 10 times more sensitive than the 17kDa protein gene end-point PCR used as the reference method. The assay only recognized gDNA from SFG and transitional group (TRG) rickettsia species tested but did not detect gDNA from typhus group (TG) rickettsia species or closely or distantly related bacterial species. The SFGR-LAMP assay detected the same positives from a set of pooled tick and flea samples detected by end-point PCR in addition to two pooled flea samples not detected by end-point PCR. To our knowledge, this is the first study to develop a functional LAMP assay to initially screen for SFG and TRG rickettsia pathogens in field-collected ticks and fleas. With a high sensitivity and specificity, the results indicate the potential use as a field-based surveillance tool for tick and flea-borne rickettsial pathogens in resource-challenged countries.

Developmental profiles in tick water balance with a focus on the new Rocky Mountain spotted fever vector, Rhipicephalus sanguineus.

PubMed

Yoder, J A; Benoit, J B; Rellinger, E J; Tank, J L

2006-12-01

Recent reports indicate that the common brown dog tick, or kennel tick, Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) is a competent vector of Rocky Mountain spotted fever in the U.S.A. This tick is of concern to public health because of its high frequency of contact, as it has a unique ability to thrive within human homes. To assess the moisture requirements necessary for survival, water balance characteristics were determined for each developmental stage, from egg to adult. This is the first time that water relations in ticks have been assessed throughout the complete lifecycle. Notably, R. sanguineus is differentially adapted for life in a dry environment, as characterized by a suppressed water loss rate distinctive for each stage that distinguishes it from other ticks. Analysis of its dehydration tolerance limit and percentage body water content provides no evidence to suggest that the various stages of this tick can function more effectively containing less water, indicating that this species is modified for water conservation, not desiccation hardiness. All stages, eggs excepted, absorb water vapour from the air and can drink free water to replenish water stores. Developmentally, a shift in water balance strategies occurs in the transition from the larva, where the emphasis is on water gain (water vapour absorption from drier air), to the adult, where the emphasis is on water retention (low water loss rate). These results on the xerophilic-nature of R. sanguineus identify overhydration as the primary water stress, indicating that this tick is less dependent upon a moisture-rich habitat for survival, which matches its preference for a dry environment. We suggest that the controlled, host-confined conditions of homes and kennels have played a key role in promoting the ubiquitous distribution of R. sanguineus by creating isolated arid environments that enable this tick to establish within regions that are unfavourable for maintaining water balance.

Lumpy skin disease: attempted propagation in tick cell lines and presence of viral DNA in field ticks collected from naturally-infected cattle.

PubMed

Tuppurainen, E S M; Venter, E H; Coetzer, J A W; Bell-Sakyi, L

2015-03-01

Lumpy skin disease (LSD) is of substantial economic importance for the cattle industry in Africa and the Near and Middle East. Several insect species are thought to transmit the disease mechanically. Recent transmission studies have demonstrated the first evidence for a role of hard (ixodid) ticks as vectors of lumpy skin disease virus (LSDV). The aim of this study was to attempt in vitro growth of the virus in Rhipicephalus spp. tick cell lines and investigate in vivo the presence of the virus in ticks collected from cattle during LSD outbreaks in Egypt and South Africa. No evidence was obtained for replication of LSDV in tick cell lines although the virus was remarkably stable, remaining viable for 35 days at 28°C in tick cell cultures, in growth medium used for tick cells and in phosphate buffered saline. Viral DNA was detected in two-thirds of the 56 field ticks, making this the first report of the presence of potentially virulent LSDV in ticks collected from naturally infected animals. Crown Copyright © 2014. Published by Elsevier GmbH. All rights reserved.

Vertebrate Ticks Distribution and Their Role as Vectors in Relation to Road Edges and Underpasses.

PubMed

Delgado, Juan D; Abreu-Yanes, Estefanía; Abreu-Acosta, Néstor; Flor, Manuel D; Foronda, Pilar

2017-06-01

Roads fragment vertebrate populations and affect the dynamics and dispersal patterns of vertebrate parasites. We evaluated how vertebrate ticks distribute near roads and road underpasses in human-caused road-fragmented landscapes in Seville, SW Spain. We sampled 49 stations with 93 individualized sampling points and assessed tick abundance. We explored the relationship between tick presence and abundance and distance to the nearest road and underpass (drainage culverts and other passages used by vertebrates), and landscape features through categorical regression and nonparametric statistics. The presence of the tick-borne pathogens Borrelia sp. and Bartonella sp. was also analyzed by PCR. We found preliminary evidence of high relative tick abundance next to roads and in the vicinity of road underpasses. Plant cover type was related to tick presence in this road context. Implications of road permeability and edge effect in patterns of vertebrate-tick relationships in road fragmentation contexts are discussed. Both Borrelia sp. and Bartonella sp. were detected in the ticks analyzed. This is the first report of these bacteria in ticks from Seville. The results confirm the potential risk of acquiring Lyme disease and bartonellosis in this area.

Evaluation of Gulf Coast Ticks (Acari: Ixodidae) for Ehrlichia and Anaplasma Species.

PubMed

Allerdice, Michelle E J; Hecht, Joy A; Karpathy, Sandor E; Paddock, Christopher D

2017-03-01

Amblyomma maculatum Koch (the Gulf Coast tick) is an aggressive, human-biting ixodid tick distributed throughout much of the southeastern United States and is the primary vector for Rickettsia parkeri, an emerging human pathogen. Amblyomma maculatum has diverse host preferences that include white-tailed deer, a known reservoir for Ehrlichia and Anaplasma species, including the human pathogens E. ewingii and E. chaffeensis. To examine more closely the potential role of A. maculatum in the maintenance of various pathogenic Ehrlichia and Anaplasma species, we screened DNA samples from 493 questing adult A. maculatum collected from six U.S. states using broad-range Anaplasmataceae and Ehrlichia genus-specific PCR assays. Of the samples tested, four (0.8%) were positive for DNA of Ehrlichia ewingii, one (0.2%) was positive for Anaplasma platys, and one (0.2%) was positive for a previously unreported Ehrlichia species closely related to Ehrlichia muris and an uncultivated Ehrlichia species from Haemaphysalis longicornis ticks in Japan. No ticks contained DNA of Ehrlichia chaffeensis, Ehrlichia canis, the Panola Mountain Ehrlichia, or Anaplasma phagocytophilum. This is the first identification of E. ewingii, A. platys, and the novel Ehrlichia in questing Gulf Coast ticks; nonetheless the low prevalence of these agents suggests that A. maculatum is not likely an important vector of these zoonotic pathogens. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.

Non-systemic transmission of tick-borne diseases: A network approach

NASA Astrophysics Data System (ADS)

Ferreri, Luca; Bajardi, Paolo; Giacobini, Mario

2016-10-01

Tick-borne diseases can be transmitted via non-systemic (NS) transmission. This occurs when tick gets the infection by co-feeding with infected ticks on the same host resulting in a direct pathogen transmission between the vectors, without infecting the host. This transmission is peculiar, as it does not require any systemic infection of the host. The NS transmission is the main efficient transmission for the persistence of the tick-borne encephalitis virus in nature. By describing the heterogeneous ticks aggregation on hosts through a bipartite graphs representation, we are able to mathematically define the NS transmission and to depict the epidemiological conditions for the pathogen persistence. Despite the fact that the underlying network is largely fragmented, analytical and computational results show that the larger is the variability of the aggregation, and the easier is for the pathogen to persist in the population.

Synanthropic Mammals as Potential Hosts of Tick-Borne Pathogens in Panama.

PubMed

Bermúdez, Sergio E; Gottdenker, Nicole; Krishnvajhala, Aparna; Fox, Amy; Wilder, Hannah K; González, Kadir; Smith, Diorene; López, Marielena; Perea, Milixa; Rigg, Chystrie; Montilla, Santiago; Calzada, José E; Saldaña, Azael; Caballero, Carlos M; Lopez, Job E

2017-01-01

Synanthropic wild mammals can be important hosts for many vector-borne zoonotic pathogens. The aim of this study was determine the exposure of synanthropic mammals to two types of tick-borne pathogens in Panama, spotted fever group Rickettsia (SFGR) and Borrelia relapsing fever (RF) spirochetes. One hundred and thirty-one wild mammals were evaluated, including two gray foxes, two crab-eating foxes (from zoos), four coyotes, 62 opossum and 63 spiny rats captured close to rural towns. To evaluate exposure to SFGR, serum samples from the animals were tested by indirect immunofluorescence assay (IFA) using Rickettsia rickettsii and Candidatus Rickettsia amblyommii antigen. Immunoblotting was performed using Borrelia turicatae protein lysates and rGlpQ, to assess infection caused by RF spirochetes. One coyote (25%) and 27 (43%) opossums showed seroreactivity to SFGR. Of these opossums, 11 were seroreactive to C. R. amblyommii. Serological reactivity was not detected to B. turicatae in mammal samples. These findings may reflect a potential role of both mammals in the ecology of tick-borne pathogens in Panama.

A study of ticks and tick-borne livestock pathogens in Pakistan.

PubMed

Karim, Shahid; Budachetri, Khemraj; Mukherjee, Nabanita; Williams, Jaclyn; Kausar, Asma; Hassan, Muhammad Jawadul; Adamson, Steven; Dowd, Scot E; Apanskevich, Dmitry; Arijo, Abdullah; Sindhu, Zia Uddin; Kakar, Muhammad Azam; Khan, Raja Muhammad Dilpazir; Ullah, Shafiq; Sajid, Muhammad Sohail; Ali, Abid; Iqbal, Zafar

2017-06-01

As obligate blood-feeding arthropods, ticks transmit pathogens to humans and domestic animals more often than other arthropod vectors. Livestock farming plays a vital role in the rural economy of Pakistan, and tick infestation causes serious problems with it. However, research on tick species diversity and tick-borne pathogens has rarely been conducted in Pakistan. In this study, a systematic investigation of the tick species infesting livestock in different ecological regions of Pakistan was conducted to determine the microbiome and pathobiome diversity in the indigenous ticks. A total of 3,866 tick specimens were morphologically identified as 19 different tick species representing three important hard ticks, Rhipicephalus, Haemaphysalis and Hyalomma, and two soft ticks, Ornithodorus and Argas. The bacterial diversity across these tick species was assessed by bacterial 16S rRNA gene sequencing using a 454-sequencing platform on 10 of the different tick species infesting livestock. The notable genera detected include Ralstonia, Clostridium, Staphylococcus, Rickettsia, Lactococcus, Lactobacillus, Corynebacterium, Enterobacter, and Enterococcus. A survey of Spotted fever group rickettsia from 514 samples from the 13 different tick species generated rickettsial-specific amplicons in 10% (54) of total ticks tested. Only three tick species Rhipicephalus microplus, Hyalomma anatolicum, and H. dromedarii had evidence of infection with "Candidatus Rickettsia amblyommii" a result further verified using a rompB gene-specific quantitative PCR (qPCR) assay. The Hyalomma ticks also tested positive for the piroplasm, Theileria annulata, using a qPCR assay. This study provides information about tick diversity in Pakistan, and pathogenic bacteria in different tick species. Our results showed evidence for Candidatus R. amblyommii infection in Rhipicephalus microplus, H. anatolicum, and H. dromedarii ticks, which also carried T. annulata.

A study of ticks and tick-borne livestock pathogens in Pakistan

PubMed Central

Budachetri, Khemraj; Mukherjee, Nabanita; Williams, Jaclyn; Kausar, Asma; Hassan, Muhammad Jawadul; Adamson, Steven; Dowd, Scot E.; Apanskevich, Dmitry; Arijo, Abdullah; Sindhu, Zia Uddin; Kakar, Muhammad Azam; Khan, Raja Muhammad Dilpazir; Ullah, Shafiq; Sajid, Muhammad Sohail; Ali, Abid; Iqbal, Zafar

2017-01-01

Background As obligate blood-feeding arthropods, ticks transmit pathogens to humans and domestic animals more often than other arthropod vectors. Livestock farming plays a vital role in the rural economy of Pakistan, and tick infestation causes serious problems with it. However, research on tick species diversity and tick-borne pathogens has rarely been conducted in Pakistan. In this study, a systematic investigation of the tick species infesting livestock in different ecological regions of Pakistan was conducted to determine the microbiome and pathobiome diversity in the indigenous ticks. Methodology/Principal findings A total of 3,866 tick specimens were morphologically identified as 19 different tick species representing three important hard ticks, Rhipicephalus, Haemaphysalis and Hyalomma, and two soft ticks, Ornithodorus and Argas. The bacterial diversity across these tick species was assessed by bacterial 16S rRNA gene sequencing using a 454-sequencing platform on 10 of the different tick species infesting livestock. The notable genera detected include Ralstonia, Clostridium, Staphylococcus, Rickettsia, Lactococcus, Lactobacillus, Corynebacterium, Enterobacter, and Enterococcus. A survey of Spotted fever group rickettsia from 514 samples from the 13 different tick species generated rickettsial-specific amplicons in 10% (54) of total ticks tested. Only three tick species Rhipicephalus microplus, Hyalomma anatolicum, and H. dromedarii had evidence of infection with “Candidatus Rickettsia amblyommii” a result further verified using a rompB gene-specific quantitative PCR (qPCR) assay. The Hyalomma ticks also tested positive for the piroplasm, Theileria annulata, using a qPCR assay. Conclusions/Significance This study provides information about tick diversity in Pakistan, and pathogenic bacteria in different tick species. Our results showed evidence for Candidatus R. amblyommii infection in Rhipicephalus microplus, H. anatolicum, and H. dromedarii ticks, which also carried T. annulata. PMID:28650978

Prevention and control strategies for ticks and pathogen transmission.

PubMed

de La Fuente, J; Kocan, K M; Contreras, M

2015-04-01

Ticks and tick-borne pathogens have evolved together, resulting in a complex relationship in which the pathogen's life cycle is perfectly coordinated with the tick's feeding cycle, and the tick can harbour high pathogen levels without affecting its biology. Tick-borne diseases (TBDs) continue to emerge and/or spread, and pose an increasing threatto human and animal health. The disruptive impacts of global change have resulted in ecosystem instability and the future outcomes of management and control programmes for ticks and TBDs are difficult to predict. In particular, the selection of acaricide-resistant ticks has reduced the value of acaricides as a sole means of tick control. Vaccines provide an alternative control method, but the use of tick vaccines has not advanced since the first vaccines were registered in the early 1990s. An understanding of the complex molecular relationship between hosts, ticks and pathogens and the use of systems biology and vaccinomics approaches are needed to discover proteins with the relevant biological function in tick feeding, reproduction, development, immune response, the subversion of host immunity and pathogen transmission, all of which mediate tick and pathogen success. The same approaches will also be required to characterise candidate protective antigens and to validate vaccine formulations. Tick vaccines with a dual effect on tick infestations and pathogen transmission could reduce both tick infestations and their vector capacity for humans, animals and reservoir hosts. The development of integrated tick control strategies, including vaccines and synthetic and botanical acaricides, in combination with managing drug resistance and educating producers, should lead to the sustainable control of ticks and TBDs.

Virome Analysis of Amblyomma americanum, Dermacentor variabilis, and Ixodes scapularis Ticks Reveals Novel Highly Divergent Vertebrate and Invertebrate Viruses

PubMed Central

Williams, Simon Hedley; Sameroff, Stephen; Sanchez Leon, Maria; Jain, Komal; Lipkin, W. Ian

2014-01-01

ABSTRACT A wide range of bacterial pathogens have been identified in ticks, yet the diversity of viruses in ticks is largely unexplored. In the United States, Amblyomma americanum, Dermacentor variabilis, and Ixodes scapularis are among the principal tick species associated with pathogen transmission. We used high-throughput sequencing to characterize the viromes of these tick species and identified the presence of Powassan virus and eight novel viruses. These included the most divergent nairovirus described to date, two new clades of tick-borne phleboviruses, a mononegavirus, and viruses with similarity to plant and insect viruses. Our analysis revealed that ticks are reservoirs for a wide range of viruses and suggests that discovery and characterization of tick-borne viruses will have implications for viral taxonomy and may provide insight into tick-transmitted diseases. IMPORTANCE Ticks are implicated as vectors of a wide array of human and animal pathogens. To better understand the extent of tick-borne diseases, it is crucial to uncover the full range of microbial agents associated with ticks. Our current knowledge of the diversity of tick-associated viruses is limited, in part due to the lack of investigation of tick viromes. In this study, we examined the viromes of three tick species from the United States. We found that ticks are hosts to highly divergent viruses across several taxa, including ones previously associated with human disease. Our data underscore the diversity of tick-associated viruses and provide the foundation for further studies into viral etiology of tick-borne diseases. PMID:25056893

Acquisition and transmission of Hepatozoon canis (Apicomplexa: Hepatozoidae) by the tick Amblyomma ovale (Acari: Ixodidae).

PubMed

Rubini, A S; Paduan, K S; Martins, T F; Labruna, M B; O'Dwyer, L H

2009-10-14

The present study aimed to evaluate under controlled conditions the acquisition of Hepatozoon canis by Amblyomma ovale after feeding on infected dogs, and the subsequent induction of infection in uninfected dogs that ingested the experimentally infected ticks. Two H. canis naturally infected dogs were infested with A. ovale adult ticks derived from an uninfected laboratory tick colony. After feeding, two A. ovale females presented H. canis oocysts in the hemolymph at the first and fourth days after removal of ticks from dogs. The oocysts had an average size of 244.34 microm x 255.46 microm. Three uninfected dogs were fed with ticks previously fed on the infected dogs. Only one dog became infected 32 days after oral inoculation, presenting circulating gametocytes, parasitemia less than 1%, and positive PCR confirmed to be H. canis by DNA sequencing. The results obtained indicated A. ovale ticks as potential vector of H. canis in rural areas of Brazil.

First detection of Rickettsia conorii ssp. caspia in Rhipicephalus sanguineus in Zambia.

PubMed

Chitimia-Dobler, Lidia; Dobler, Gerhard; Schaper, Sabine; Küpper, Thomas; Kattner, Simone; Wölfel, Silke

2017-11-01

Ticks are important vectors for Rickettsia spp. of the spotted fever group all around the world. Rickettsia conorii is the etiological agent of boutonneuse fever in the Mediterranean region and Africa. Tick identification was based on morphological features and further characterized using the 16S rRNA gene. The ticks were individually tested using pan-Rickettsia real-time-PCR for screening, and 23S-5S intergenic spacer region, 16S rDNA, gltA, sca4, ompB, and ompA genes were used to analyze the Rickettsia positive samples. Rickettsia conorii ssp. caspia was detected in tick collected in Zambia for the first time, thus demonstrating the possibility of the occurrence of human disease, namely Astrakhan fever, due to this Rickettsia ssp. in this region of Africa. The prevalence of R. conorii ssp. caspia was 0.06% (one positive tick out of 1465 tested ticks) and 0.07% (one positive tick out of 1254 tested Rh. sanguineus).

Borrelia crocidurae in Ornithodoros ticks from northwestern Morocco: a range extension in relation to climatic change?

PubMed

Souidi, Yassine; Boudebouch, Najma; Ezikouri, Sayeh; Belghyti, Driss; Trape, Jean-François; Sarih, M'hammed

2014-12-01

Tick-borne relapsing fever (TBRF) is caused by Borrelia spirochetes transmitted to humans by Argasid soft ticks of the genus Ornithodoros. We investigated the presence of Ornithodoros ticks in rodent burrows in nine sites of the Gharb region of northwestern Morocco where we recently documented a high incidence of TBRF in humans. We assessed the Borrelia infection rate by nested PCR and sequencing. All sites investigated were colonized by ticks of the Ornithodoros marocanus complex and a high proportion of burrows (38.4%) were found to be infested. Borrelia infections were observed in 6.8% of the ticks tested. Two Borrelia species were identified by sequencing: B. hispanica and B. crocidurae. The discovery in northwestern Morocco of Ornithodoros ticks infected by B. crocidurae represents a 350 km range extension of this Sahelo-Saharan spirochete in North Africa. The spread of B. crocidurae may be related to the increasing aridity of northwestern Morocco in relation to climate change. © 2014 The Society for Vector Ecology.

Hyalomma ticks on northward migrating birds in southern Spain: Implications for the risk of entry of Crimean-Congo haemorrhagic fever virus to Great Britain.

PubMed

England, Marion E; Phipps, Paul; Medlock, Jolyon M; Atkinson, Peter M; Atkinson, Barry; Hewson, Roger; Gale, Paul

2016-06-01

Crimean-Congo haemorrhagic fever virus (CCHFV) is a zoonotic virus transmitted by Hyalomma ticks, the immature stages of which may be carried by migratory birds. In this study, a total of 12 Hyalomma ticks were recovered from five of 228 migratory birds trapped in Spring, 2012 in southern Spain along the East Atlantic flyway. All collected ticks tested negative for CCHFV. While most birds had zero Hyalomma ticks, two individuals had four and five ticks each and the statistical distribution of Hyalomma tick counts per bird is over-dispersed compared to the Poisson distribution, demonstrating the need for intensive sampling studies to avoid underestimating the total number of ticks. Rates of tick exchange on migratory birds during their northwards migration will affect the probability that a Hyalomma tick entering Great Britain is positive for CCHFV. Drawing on published data, evidence is presented that the latitude of a European country affects the probability of entry of Hyalomma ticks on wild birds. Further data on Hyalomma infestation rates and tick exchange rates are required along the East Atlantic flyway to further our understanding of the origin of Hyalomma ticks (i.e., Africa or southern Europe) and hence the probability of entry of CCHFV into GB. © 2016 The Society for Vector Ecology.

Exosome-Mediated Pathogen Transmission by Arthropod Vectors.

PubMed

Hackenberg, Michael; Kotsyfakis, Michail

2018-04-24

Recent molecular and cellular studies have highlighted a potentially important role for tick exosomes in parasite transmission. Here we summarize evolving hypotheses about the largely unknown cellular events that may take place at the tick-host-pathogen interface, focusing on a potential role for arthropod exosomes in this tripartite interaction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Induction of humoral immune response to multiple recombinant rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission

USDA-ARS?s Scientific Manuscript database

Background: Rhipicephalus appendiculatus is the primary vector of Theileria parva, the etiologic agent of East Coast fever (ECF), a devastating disease of cattle in sub-Saharan Africa. We hypothesized that a vaccine targeting tick proteins that are involved in attachment and feeding might affect fee...

The babesia bovis hap2 gene is not required for blood stage replication, but expressed upon in vitro sexual stage induction

USDA-ARS?s Scientific Manuscript database

Babesia bovis, is a tick borne apicomplexan parasite responsible for important cattle losses globally. Babesia parasites have a complex life cycle including asexual replication in the mammalian host and sexual reproduction in the tick vector. Novel control strategies aimed at limiting transmission o...

A Novel Carbamate Insecticide with Superior Selectivity for Cattle Tick (Boophilus microplus) and Sand Fly (Phlebotomus papatasi) Control

USDA-ARS?s Scientific Manuscript database

The cattle tick, Boophilus microplus, and the sand fly, Phlebotomus papatasi (Pp), are vectors of infectious agents affecting cattle and humans, respectively. The purpose of this study was to characterize the inhibitor profile of acetylcholinesterases from R. microplus(BmAChE1) and Pp (PpAchE) for c...

The mitochondrial genome of a Texas outbreak strain of the cattle tick, Rhipicephalus (Boophilus) microplus, derived from whole genome sequencing Pacific Biosciences and Illumina reads

USDA-ARS?s Scientific Manuscript database

The cattle fever tick, Rhipicephalus (Boophilus) microplus is one of the most significant medical veterinary pests in the world, vectoring several serious livestock diseases negatively impacting agricultural economies of tropical and subtropical countries around the world. We assembled the complete ...

Interaction of the tick immune system with transmitted pathogens

PubMed Central

Hajdušek, Ondřej; Šíma, Radek; Ayllón, Nieves; Jalovecká, Marie; Perner, Jan; de la Fuente, José; Kopáček, Petr

2013-01-01

Ticks are hematophagous arachnids transmitting a wide variety of pathogens including viruses, bacteria, and protozoans to their vertebrate hosts. The tick vector competence has to be intimately linked to the ability of transmitted pathogens to evade tick defense mechanisms encountered on their route through the tick body comprising midgut, hemolymph, salivary glands or ovaries. Tick innate immunity is, like in other invertebrates, based on an orchestrated action of humoral and cellular immune responses. The direct antimicrobial defense in ticks is accomplished by a variety of small molecules such as defensins, lysozymes or by tick-specific antimicrobial compounds such as microplusin/hebraein or 5.3-kDa family proteins. Phagocytosis of the invading microbes by tick hemocytes is likely mediated by the primordial complement-like system composed of thioester-containing proteins, fibrinogen-related lectins and convertase-like factors. Moreover, an important role in survival of the ingested microbes seems to be played by host proteins and redox balance maintenance in the tick midgut. Here, we summarize recent knowledge about the major components of tick immune system and focus on their interaction with the relevant tick-transmitted pathogens, represented by spirochetes (Borrelia), rickettsiae (Anaplasma), and protozoans (Babesia). Availability of the tick genomic database and feasibility of functional genomics based on RNA interference greatly contribute to the understanding of molecular and cellular interplay at the tick-pathogen interface and may provide new targets for blocking the transmission of tick pathogens. PMID:23875177

Prevalence of tick-borne pathogens in ticks collected from migratory birds in Latvia.

PubMed

Capligina, Valentina; Salmane, Ineta; Keišs, Oskars; Vilks, Karlis; Japina, Kristine; Baumanis, Viesturs; Ranka, Renate

2014-02-01

Migratory birds act as hosts and long-distance vectors for several tick-borne infectious agents. Here, feeding Ixodes ticks were collected from migratory birds during the autumn migration period in Latvia and screened for the presence of epidemiologically important non-viral pathogens. A total of 93 DNA samples of ticks (37 larvae and 56 nymphs) removed from 41 birds (order Passeriformes, 9 species) was tested for Lyme borreliosis spirochaetes, Anaplasma phagocytophilum, Rickettsia spp., and Babesia spp. Borrelia burgdorferi DNA was detected in 18% of the tick samples, and a majority of infected ticks were from thrush (Turdus spp.) birds. Among the infected ticks, Borrelia valaisiana was detected in 41% of cases, Borrelia garinii in 35%, and mixed Bo. valaisiana and Bo. garinii infection in 24%. Anaplasma phagocytophilum DNA was detected in 2% of ticks, R. helvetica in 12%, and Babesia spp. pathogens in 4% of ticks. Among these samples, 3 Babesia species were identified: Ba. divergens, Ba. microti, and Ba. venatorum. Coinfection with different pathogens that included mixed infections with different Borrelia genospecies was found in 20% of nymphal and 3% of larval Ixodes ticks. These results suggest that migratory birds may support the circulation and spread of medically significant zoonoses in Europe. Copyright © 2013 Elsevier GmbH. All rights reserved.

Ticks and tick-borne pathogens of dogs along an elevational and land-use gradient in Chiriquí province, Panamá.

PubMed

Ferrell, A Michelle; Brinkerhoff, R Jory; Bernal, Juan; Bermúdez, Sergio E

2017-04-01

Systematic acarological surveys are useful tools in assessing risk to tick-borne infections, especially in areas where consistent clinical surveillance for tick-borne disease is lacking. Our goal was to identify environmental predictors of tick burdens on dogs and tick-borne infectious agents in dog-derived ticks in the Chiriquí Province of western Panama to draw inferences about spatio-temporal variation in human risk to tick-borne diseases. We used a model-selection approach to test the relative importance of elevation, human population size, vegetative cover, and change in landuse on patterns of tick parasitism on dogs. We collected 2074 ticks, representing four species (Rhipicephalus sanguineus, R. microplus, Amblyomma ovale, and Ixodes boliviensis) from 355 dogs. Tick prevalence ranged from 0 to 74% among the sites we sampled, and abundance ranged from 0 to 20.4 ticks per dog with R. sanguineus s.l. being the most commonly detected tick species (97% of all ticks sampled). Whereas elevation was the best single determinant of tick prevalence and abundance on dogs, the top models also included predictor variables describing vegetation cover and landuse change. Specifically, low-elevation areas associated with decreasing vegetative cover were associated with highest tick occurrence on dogs, potentially because of the affinity of R. sanguineus for human dwellings. Although we found low prevalence of tick-borne pathogen genera (two Rickettsia-positive ticks, no R. rickettsia or Ehrlichia spp.) in our study, all of the tick species we collected from dogs are known vectors of zoonotic pathogens. In areas where epidemiological surveillance infrastructure is limited, field-based assessments of acarological risk can be useful and cost-effective tools in efforts to identify high-risk environments for tick-transmitted pathogens.

Rhipicephalus appendiculatus ticks transmit Theileria parva from persistently infected cattle in the absence of detectable parasitemia: implications for East Coast fever epidemiology.

PubMed

Olds, Cassandra L; Mason, Kathleen L; Scoles, Glen A

2018-03-02

East Coast fever (ECF) is a devastating disease of cattle and a significant constraint to improvement of livestock production in sub-Saharan Africa. The protozoan parasite causing ECF, Theileria parva, undergoes obligate sexual stage development in its tick vector Rhipicephalus appendiculatus. Tick-borne acquisition and transmission occurs transstadially; larval and nymphal ticks acquire infection while feeding and transmit to cattle when they feed after molting to the next stage. Much of the current knowledge relating to tick-borne acquisition and transmission of T. parva has been derived from studies performed during acute infections where parasitemia is high. In contrast, tick-borne transmission during the low-level persistent infections characteristic of endemic transmission cycles is rarely studied. Cattle were infected with one of two stocks of T. parva (Muguga or Marikebuni). Four months post-infection when parasites were no longer detectable in peripheral blood by PCR, 500 R. appendiculatus nymphs were fed to repletion on each of the cattle. After they molted to the adult stage, 20 or 200 ticks, respectively, were fed on two naïve cattle for each of the parasite stocks. After adult ticks fed to repletion, cattle were tested for T. parva infection by nested PCR and dot blot hybridization. Once they had molted to adults the ticks that had fed as nymphs on Muguga and Marikebuni infected cattle successfully transmitted Theileria parva to all naïve cattle, even though T. parva infection was not detectable by nested PCR on salivary gland genomic DNA of a sample of individual ticks. However, a salivary gland homogenate from a single Marikebuni infected tick was able to infect primary bovine lymphocytes. Infection was detected by nested p104 PCR in 3 of 4 calves and detected in all 4 calves by T. parva 18S nested PCR/dot blot hybridization. We show that R. appendiculatus ticks are able to acquire T. parva parasites from infected cattle even in the absence of detectable parasitemia. Although infection was undetectable in a sample of individual ticks, cumulatively as few as 20 ticks were able to transmit T. parva to naïve cattle. These results have important implications for our understanding of T. parva transmission by R. appendiculatus in ECF endemic regions.

Changes in the geographical distribution and abundance of the tick Ixodes ricinus during the past 30 years in Sweden

PubMed Central

2012-01-01

Background Ixodes ricinus is the main vector in Europe of human-pathogenic Lyme borreliosis (LB) spirochaetes, the tick-borne encephalitis virus (TBEV) and other pathogens of humans and domesticated mammals. The results of a previous 1994 questionnaire, directed at people living in Central and North Sweden (Svealand and Norrland) and aiming to gather information about tick exposure for humans and domestic animals, suggested that Ixodes ricinus ticks had become more widespread in Central Sweden and the southern part of North Sweden from the early 1980s to the early 1990s. To investigate whether the expansion of the tick's northern geographical range and the increasing abundance of ticks in Sweden were still occurring, in 2009 we performed a follow-up survey 16 years after the initial study. Methods A questionnaire similar to the one used in the 1994 study was published in Swedish magazines aimed at dog owners, home owners, and hunters. The questionnaire was published together with a popular science article about the tick's biology and role as a pathogen vector in Sweden. The magazines were selected to get information from people familiar with ticks and who spend time in areas where ticks might be present. Results Analyses of data from both surveys revealed that during the near 30-year period from the early 1980s to 2008, I. ricinus has expanded its distribution range northwards. In the early 1990s ticks were found in new areas along the northern coastline of the Baltic Sea, while in the 2009 study, ticks were reported for the first time from many locations in North Sweden. This included locations as far north as 66°N and places in the interior part of North Sweden. During this 16-year period the tick's range in Sweden was estimated to have increased by 9.9%. Most of the range expansion occurred in North Sweden (north of 60°N) where the tick's coverage area doubled from 12.5% in the early 1990s to 26.8% in 2008. Moreover, according to the respondents, the abundance of ticks had increased markedly in LB- and TBE-endemic areas in South (Götaland) and Central Sweden. Conclusions The results suggest that I. ricinus has expanded its range in North Sweden and has become distinctly more abundant in Central and South Sweden during the last three decades. However, in the northern mountain region I. ricinus is still absent. The increased abundance of the tick can be explained by two main factors: First, the high availability of large numbers of important tick maintenance hosts, i.e., cervids, particularly roe deer (Capreolus capreolus) during the last three decades. Second, a warmer climate with milder winters and a prolonged growing season that permits greater survival and proliferation over a larger geographical area of both the tick itself and deer. High reproductive potential of roe deer, high tick infestation rate and the tendency of roe deer to disperse great distances may explain the range expansion of I. ricinus and particularly the appearance of new TBEV foci far away from old TBEV-endemic localities. The geographical presence of LB in Sweden corresponds to the distribution of I. ricinus. Thus, LB is now an emerging disease risk in many parts of North Sweden. Unless countermeasures are undertaken to keep the deer populations, particularly C. capreolus and Dama dama, at the relatively low levels that prevailed before the late 1970s - especially in and around urban areas where human population density is high - by e.g. reduced hunting of red fox (Vulpes vulpes) and lynx (Lynx lynx), the incidences of human LB and TBE are expected to continue to be high or even to increase in Sweden in coming decades. PMID:22233771

Update on Tick-Borne Rickettsioses around the World: a Geographic Approach

PubMed Central

Paddock, Christopher D.; Socolovschi, Cristina; Labruna, Marcelo B.; Mediannikov, Oleg; Kernif, Tahar; Abdad, Mohammad Yazid; Stenos, John; Bitam, Idir; Fournier, Pierre-Edouard; Raoult, Didier

2013-01-01

SUMMARY Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases. PMID:24092850

Update on Tick-Borne Bacterial Diseases in Travelers.

PubMed

Eldin, Carole; Parola, Philippe

2018-05-22

Ticks are the second most important vectors of infectious diseases after mosquitoes worldwide. The growth of international tourism including in rural and remote places increasingly exposes travelers to tick bite. Our aim was to review the main tick-borne infectious diseases reported in travelers in the past 5 years. In recent years, tick-borne bacterial diseases have emerged in travelers including spotted fever group (SFG) rickettsioses, borrelioses, and diseases caused by bacteria of the Anaplasmataceae family. African tick-bite fever, due to Rickettsia africae, is the most frequent agent reported in travelers returned from Sub-Saharan areas. Other SFG agents are increasingly reported in travelers, and clinicians should be aware of them. Lyme disease can be misdiagnosed in Southern countries. Organisms causing tick-borne relapsing fever are neglected pathogens worldwide, and reports in travelers have allowed the description of new species. Infections due to Anaplasmataceae bacteria are more rarely described in travelers, but a new species of Neoehrlichia has recently been detected in a traveler. The treatment of these infections relies on doxycycline, and travelers should be informed before the trip about prevention measures against tick bites.

Molecular detection of Theileria spp. and Babesia spp. in sheep and ixodid ticks from the northeast of Iran.

PubMed

Razmi, Gholamreza; Pourhosseini, Moslem; Yaghfouri, Saeed; Rashidi, Ahmad; Seidabadi, Mohsen

2013-02-01

Theilerioses and babesioses are important diseases in Iranian sheep. The present study was undertaken to identify and classify/specify Theileria spp. and Babesia spp. in sheep and vector ticks. Investigation was carried out from 2009 to 2011 in the Khorasan Razavi Province, Iran. In total, 302 sheep originating from 60 different flocks were clinically examined and their blood collected. In addition, from the same flocks, ixodid ticks were sampled. Stained blood smears were microscopically examined for the presence of Theileria and Babesia organisms, and a semi-nested PCR was used for subsequent molecular specification. From the ticks, salivary glands and uterus were isolated and subsequently analyzed by semi-nested PCR. Piroplasm organisms were observed in 29% of the blood smears with low parasitemia, whereas 65% of the blood samples yielded positive PCR findings. The presence of Theileria ovis (55.6%), Theileria lestoquardi, and mixed infection with Theileria spp. and Babesia ovis were detected by semi-nested PCR in 0.3%, 5.6%, and 0.99%, respectively. In total, 429 ixodid ticks were collected from different areas of the province. The most prevalent ticks were Rhipicephalus turanicus (n = 376; 87.6% of the total), followed by Hyalomma marginatum turanicum (n = 30; 7.0%), Dermacentor raskemensis (n = 12; 2.8%), Hyalomma anatolicum anatolicum (n = 7; 1.6%), Dermacentor marginatus (n = 2; 0.5%), Rhipicephalus bursa (n = 1; 0.2%), and Haemaphysalis sp. (n = 1; 0.2%). Of the positive R. turanicus samples, 5 (5.7%) were infected with T. ovis and 2 (2.9%) with T. lestoquardi. Neither Babesia ovis nor Babesia motasi infection was detected in salivary glands or uterine samples of the ticks. The results also suggest that R. turanicus could be the vector responsible for transmission of the 2 Theileria species.

Vector computer memory bank contention

NASA Technical Reports Server (NTRS)

Bailey, D. H.

1985-01-01

A number of vector supercomputers feature very large memories. Unfortunately the large capacity memory chips that are used in these computers are much slower than the fast central processing unit (CPU) circuitry. As a result, memory bank reservation times (in CPU ticks) are much longer than on previous generations of computers. A consequence of these long reservation times is that memory bank contention is sharply increased, resulting in significantly lowered performance rates. The phenomenon of memory bank contention in vector computers is analyzed using both a Markov chain model and a Monte Carlo simulation program. The results of this analysis indicate that future generations of supercomputers must either employ much faster memory chips or else feature very large numbers of independent memory banks.

Vector computer memory bank contention

NASA Technical Reports Server (NTRS)

Bailey, David H.

1987-01-01

A number of vector supercomputers feature very large memories. Unfortunately the large capacity memory chips that are used in these computers are much slower than the fast central processing unit (CPU) circuitry. As a result, memory bank reservation times (in CPU ticks) are much longer than on previous generations of computers. A consequence of these long reservation times is that memory bank contention is sharply increased, resulting in significantly lowered performance rates. The phenomenon of memory bank contention in vector computers is analyzed using both a Markov chain model and a Monte Carlo simulation program. The results of this analysis indicate that future generations of supercomputers must either employ much faster memory chips or else feature very large numbers of independent memory banks.

Geographic information systems and spatial analysis of adult Ixodes scapularis (Acari: Ixodidae) in the Middle Atlantic region of the U.S.A

USGS Publications Warehouse

Bunnell, J.E.; Price, S.D.; Das, A.; Shields, T.M.; Glass, G.E.

2003-01-01

In the Middle Atlantic region of the U.S.A., the vector of Lyme disease, human granulocytic ehrlichiosis, babesiosis, and other human and veterinary pathogens is the black-legged tick, Ixodes scapularis Say. In 1997 and 1998, 663 adult I. scapularis ticks were collected from 320 transects spanning 66,400 km2 in five states of the Middle Atlantic region. Tick abundance patterns were clustered, with relatively high numbers along the coastal plain of the Chesapeake Bay, decreasing to the west and south. There were significant associations between tick abundance and land cover, distance to water, distance to forest edge, elevation, and soil type.

Experiences in Tick Control by Acaricide in the Traditional Cattle Sector in Zambia and Burkina Faso: Possible Environmental and Public Health Implications.

PubMed

De Meneghi, Daniele; Stachurski, Frédéric; Adakal, Hassane

2016-01-01

Livestock, especially cattle, play a paramount role in agriculture production systems, particularly in poor countries throughout the world. Ticks and tick-borne diseases (TBDs) have an important impact on livestock and agriculture production in sub-Saharan Africa. The authors review the most common methods used for the control of ticks and TBDs. Special emphasis is given to the direct application of acaricides to the host animals. The possible environmental and public health adverse effects (i.e., risks for the workers, residues in the environment and in food products of animal origin) are mentioned. The authors present two case studies, describing different field experiences in controlling ticks in two African countries. In Zambia (Southern Africa), a strategic dipping regime was used to control Rhipicephalus appendiculatus ticks, vectors of theileriosis, a deadly disease affecting cattle in the traditional livestock sector in Southern Province. The dipping regime adopted allowed to reduce the tick challenge and cattle mortally rate and, at the same time, to employ less acaricide as compared to the intensive dipping used so far, without disrupting the building-up of enzootic stability. In Burkina Faso (West Africa), where dipping was never used for tick control, an acaricide footbath was employed as an alternative method to the traditional technique used locally (portable manual sprayers). This was developed from field observations on the invasion/attachment process of the Amblyomma variegatum ticks - vector of cowdriosis - on the animal hosts, leading to a control method aimed to kill ticks temporarily attached to the interdigital areas before their permanent attachment to the predilection sites. This innovative method has been overall accepted by the local farmers. It has the advantage of greatly reducing costs of treatments and has a minimal environmental impact, making footbath a sustainable and replicable method, adoptable also in other West African countries. Although the two methods described, developed in very different contexts, are not comparable - if public health and environmental implications are taken into account, if a balance among efficacy of the control method(s), cost-effectiveness and sustainability is reached - a way forward for the implementation of a One Health strategy can be set.

Matrix-assisted laser desorption/ionization time of flight mass spectrometry for comprehensive indexing of East African ixodid tick species.

PubMed

Rothen, Julian; Githaka, Naftaly; Kanduma, Esther G; Olds, Cassandra; Pflüger, Valentin; Mwaura, Stephen; Bishop, Richard P; Daubenberger, Claudia

2016-03-15

The tick population of Africa includes several important genera belonging to the family Ixodidae. Many of these ticks are vectors of protozoan and rickettsial pathogens including Theileria parva that causes East Coast fever, a debilitating cattle disease endemic to eastern, central and southern Africa. Effective surveillance of tick-borne pathogens depends on accurate identification and mapping of their tick vectors. A simple and reproducible technique for rapid and reliable differentiation of large numbers of closely related field-collected ticks, which are often difficult and tedious to discriminate purely by morphology, will be an essential component of this strategy. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) is increasingly becoming a useful tool in arthropod identification and has the potential to overcome the limitations of classical morphology-based species identification. In this study, we applied MALDI-TOF MS to a collection of laboratory and field ticks found in Eastern Africa. The objective was to determine the utility of this proteomic tool for reliable species identification of closely related afrotropical ticks. A total of 398 ixodid ticks from laboratory maintained colonies, extracted from the hides of animals or systematically collected from vegetation in Kenya, Sudan and Zimbabwe were analyzed in the present investigation. The cytochrome c oxidase I (COI) genes from 33 specimens were sequenced to confirm the tentatively assigned specimen taxa identity on the basis of morphological analyses. Subsequently, the legs of ticks were homogenized and analyzed by MALDI-TOF MS. A collection of reference mass spectra, based on the mass profiles of four individual ticks per species, was developed and deposited in the spectral database SARAMIS™. The ability of these superspectra (SSp.) to identify and reliably validate a set of ticks was demonstrated using the remaining individual 333 ticks. Ultimately, ten different tick species within the genera Amblyomma, Hyalomma, Rhipicephalus and Rhipicephalus (Boophilus) based on molecular COI typing and morphology were included into the study analysis. The robustness of the 12 distinct SSp. developed here proved to be very high, with 319 out of 333 ticks used for validation identified correctly at species level. Moreover, these novel SSp. allowed for diagnostic specificity of 99.7 %. The failure of species identification for 14 ticks was directly linked to low quality mass spectra, most likely due to poor specimen quality that was received in the laboratory before sample preparation. Our results are consistent with earlier studies demonstrating the potential of MALDI-TOF MS as a reliable tool for differentiating ticks originating from the field, especially females that are difficult to identify after blood feeding. This work provides further evidence of the utility of MALDI-TOF MS to identify morphologically and genetically highly similar tick species and indicates the potential of this tool for large-scale monitoring of tick populations, species distributions and host preferences.

Vector ecology of equine piroplasmosis

USDA-ARS?s Scientific Manuscript database

Equine piroplasmosis (EP) is a disease of equidae including horses, donkeys, mules and zebras caused by either of two protozoan parasites, Theileria equi or Babesia caballi. These parasites are biologically transmitted between hosts via tick-vectors and although they have inherent differences, they ...

Human Granulocytic Ehrlichiosis Agent Infection in a Pony Vaccinated with a Borrelia burgdorferi Recombinant OspA Vaccine and Challenged by Exposure to Naturally Infected Ticks

PubMed Central

Chang, Yung-Fu; McDonough, Sean P.; Chang, Chao-Fu; Shin, Kwang-Soon; Yen, William; Divers, Thomas

2000-01-01

A pony was vaccinated with recombinant OspA vaccine (rOspA) and then exposed 3 months later to Borrelia burgdorferi-infected ticks (Ixodes scapularis) collected in Westchester County, N.Y. At 2 weeks after tick exposure, the pony developed a high fever (105°F). Buffy coat smears showed that 20% of neutrophils contained ehrlichial inclusion bodies (morulae). Flunixin Meglumine (1 g daily) was given for 2 days, and the body temperature returned to normal. PCR for ehrlichial DNA was performed on blood samples for 10 consecutive days beginning when the pony was first febrile. This pony was monitored for another 3.5 months but developed no further clinical signs. The 44-kDa immunodominant human granulocytic ehrlichiosis antigen gene was amplified by PCR and cloned into a pCR2.1 vector. DNA sequence analysis of this gene showed it was only 8 bp different (99% identity) from the results reported by others (J.W. Ijdo et al., Infect. Immun. 66:3264–3269, 1998). Western blot analysis, growth inhibition assays, and repeated attempts to isolate B. burgdorferi all demonstrated the pony was protected against B. burgdorferi infection. These results highlight the potential for ticks to harbor and transmit several pathogens simultaneously, which further complicates the diagnosis and vaccination of these emerging tick-borne diseases. PMID:10618280

One particular Anaplasma phagocytophilum ecotype infects cattle in the Camargue, France.

PubMed

Dugat, Thibaud; Leblond, Agnès; Keck, Nicolas; Lagrée, Anne-Claire; Desjardins, Isabelle; Joulié, Aurélien; Pradier, Sophie; Durand, Benoit; Boulouis, Henri-Jean; Haddad, Nadia

2017-08-02

Anaplasma phagocytophilum is a zoonotic tick-borne pathogen responsible for granulocytic anaplasmosis, a mild to a severe febrile disease that affects man and several animal species, including cows and horses. In Europe, I. ricinus is the only proven vector for this pathogen, but studies suggest that other tick genera and species could be involved in its transmission. Our objective was to assess the presence and genetic diversity of A. phagocytophilum in domestic animals and different tick species from the Camargue region, located in the south of France. A total of 140 ticks and blood samples from 998 cattle and 337 horses were collected in Camargue and tested for the presence of A. phagocytophilum DNA by msp2 quantitative real-time PCR. Molecular typing with four markers was performed on positive samples. Anaplasma phagocytophilum DNA was detected in 6/993 (0.6%) cows, 1/20 (5%) Haemaphysalis punctata, 1/57 (1.75%) Rhipicephalus pusillus, and was absent in horses (0%). All cattle A. phagocytophilum presented a profile identical to an A. phagocytophilum variant previously detected in Dermacentor marginatus, Hyalomma marginatum, and Rhipicephalus spp. in Camargue. Our results demonstrate that one particular A. phagocytophilum variant infects cattle in Camargue, where I. ricinus is supposed to be rare or even absent. Dermacentor marginatus, Rhipicephalus spp. and Hyalomma spp., and possibly other tick species could be involved in the transmission of this variant in this region.

Tick control: trapping, biocontrol, host management and other alternative strategies

USGS Publications Warehouse

Ginsberg, Howard S.; Edited by Sonenshine, Daniel E.; Roe, R. Michael

2014-01-01

Biology of Ticks is the most comprehensive work on tick biology and tick-borne diseases. This second edition is a multi-authored work, featuring the research and analyses of renowned experts across the globe. Spanning two volumes, the book examines the systematics, biology, structure, ecological adaptations, evolution, genomics and the molecular processes that underpin the growth, development and survival of these important disease-transmitting parasites. Also discussed is the remarkable array of diseases transmitted (or caused) by ticks, as well as modern methods for their control. This book should serve as a modern reference for students, scientists, physicians, veterinarians and other specialists. Volume I covers the biology of the tick and features chapters on tick systematics, tick life cycles, external and internal anatomy, and others dedicated to specific organ systems, specifically, the tick integument, mouthparts and digestive system, salivary glands, waste removal, salivary glands, respiratory system, circulatory system and hemolymph, fat body, the nervous and sensory systems and reproductive systems. Volume II includes chapters on the ecology of non-nidicolous and nidicolous ticks, genetics and genomics (including the genome of the Lyme disease vector Ixodes scapularis) and immunity, including host immune responses to tick feeding and tick-host interactions, as well as the tick's innate immune system that prevents and/or controls microbial infections. Six chapters cover in depth the many diseases caused by the major tick-borne pathogens, including tick-borne protozoa, viruses, rickettsiae of all types, other types of bacteria (e.g., the Lyme disease agent) and diseases related to tick paralytic agents and toxins. The remaining chapters are devoted to tick control using vaccines, acaricides, repellents, biocontrol, and, finally, techniques for breeding ticks in order to develop tick colonies for scientific study.

Distributions of the vectors of heartwater, Amblyomma hebraeum and Amblyomma variegatum (Acari: Ixodidae), in Zimbabwe.

PubMed

Peter, T F; Perry, B D; O'Callaghan, C J; Medley, G F; Shumba, W; Madzima, W; Burridge, M J; Mahan, S M

1998-12-01

The tick vectors of heartwater (Cowdria ruminantium infection) in Zimbabwe, Amblyomma hebraeum and Amblyomma variegatum, historically were believed to be confined to the low-lying regions of the south and north-west of the country. However, country-wide surveys performed in 1975-1980 and 1988-1991 demonstrated that both species were also established in western parts of the highveld plateau and had started to encroach on the predominantly heartwater-free central and eastern highveld regions. To determine the current distributions of both the vectors and evaluate the potential threat of heartwater to animals in the highveld, a survey of ticks infesting cattle was performed in 1996 at 2994 locations in small-holder and large-scale commercial farming areas throughout Zimbabwe. Amblyomma hebraeum was collected at 1329 locations, A. variegatum at 72 locations and both A. hebraeum and A. variegatum at 13 locations. The results demonstrated that A. hebraeum was present, as previously recorded, throughout the southern half of the country and appeared to have undergone further limited spread into the central and eastern highveld regions. Only the northern-most region of the country appeared to be free of this species. Amblyomma variegatum was collected mainly in the north-west, as previously recorded, but was also found at isolated locations across the central highveld region and along the eastern border with Mozambique. This species was, however, still absent from the southern half and the northern-most regions of the country. An overlap of the distributions of the two species existed within a zone along the southern and eastern regions of the distribution of A. variegatum. These results suggest that the vectors of heartwater are spreading and threaten to introduce heartwater into intensive livestock-producing regions of the country.

The application of lambda-cyhalothrin in tick control.

PubMed

Jurisic, Aleksandar D; Petrovic, Aleksandra P; Rajkovic, Dragana V; Nicin, Slobodan Dj

2010-09-01

In recent years, in urban areas of Novi Sad, unique ecological conditions, specific floristic and faunistic composition and poor habits of citizens in sense of public health, facilitate the development and maintenance of ticks. Regarding the importance of ticks as vectors of severe human and animal diseases, complex and detailed studies are conducted with an aim to find the most efficient methods for tick control. Two tick species, Ixodes ricinus and Dermacentor marginatus, were identified during a 3-year period on the territory of Municipality of Novi Sad. During 2006, the efficacy of the pyrethroid lambda-cyhalothrin in tick control varied from 60.7 to 100%. The highest efficacy recorded in 2007 was 92.3%. The efficacy of lambda-cyhalothrin in 2008 varied from 39.1 to 100%. Lambda-cyhalothrin showed high efficacy in tick control at localities which were improved before the application (mowed, litter removed, abundance control and euthanasia of abandoned cats and dogs). The results of this research indicate that lambda-cyhalothrin has a toxic effect on ticks and could be used as efficient acaricide for tick control, although its efficacy depends on formulation, terrain features and methods of application.

Feeding of ticks on animals for transmission and xenodiagnosis in Lyme disease research.

PubMed

Embers, Monica E; Grasperge, Britton J; Jacobs, Mary B; Philipp, Mario T

2013-08-31

Transmission of the etiologic agent of Lyme disease, Borrelia burgdorferi, occurs by the attachment and blood feeding of Ixodes species ticks on mammalian hosts. In nature, this zoonotic bacterial pathogen may use a variety of reservoir hosts, but the white-footed mouse (Peromyscus leucopus) is the primary reservoir for larval and nymphal ticks in North America. Humans are incidental hosts most frequently infected with B. burgdorferi by the bite of ticks in the nymphal stage. B. burgdorferi adapts to its hosts throughout the enzootic cycle, so the ability to explore the functions of these spirochetes and their effects on mammalian hosts requires the use of tick feeding. In addition, the technique of xenodiagnosis (using the natural vector for detection and recovery of an infectious agent) has been useful in studies of cryptic infection. In order to obtain nymphal ticks that harbor B. burgdorferi, ticks are fed live spirochetes in culture through capillary tubes. Two animal models, mice and nonhuman primates, are most commonly used for Lyme disease studies involving tick feeding. We demonstrate the methods by which these ticks can be fed upon, and recovered from animals for either infection or xenodiagnosis.

Widespread Rickettsia spp. Infections in Ticks (Acari: Ixodoidea) in Taiwan.

PubMed

Kuo, Chi-Chien; Shu, Pei-Yun; Mu, Jung-Jung; Lee, Pei-Lung; Wu, Yin-Wen; Chung, Chien-Kung; Wang, Hsi-Chieh

2015-09-01

Ticks are second to mosquitoes as the most important disease vectors, and recent decades have witnessed the emergence of many novel tick-borne rickettsial diseases, but systematic surveys of ticks and tick-borne rickettsioses are generally lacking in Asia. We collected and identified ticks from small mammal hosts between 2006 and 2010 in different parts of Taiwan. Rickettsia spp. infections in ticks were identified by targeting ompB and gltA genes with nested polymerase chain reaction. In total, 2,732 ticks were collected from 1,356 small mammals. Rhipicephalus haemaphysaloides Supino (51.8% of total ticks), Haemaphysalis bandicota Hoogstraal & Kohls (28.0%), and Ixodes granulatus Supino (20.0%) were the most common tick species, and Rattus losea Swinhoe (44.7% of total ticks) and Bandicota indica Bechstein (39.9%) were the primary hosts. The average Rickettsia infective rate in 329 assayed ticks was 31.9% and eight Rickettsia spp. or closely related species were identified. This study shows that rickettsiae-infected ticks are widespread in Taiwan, with a high diversity of Rickettsia spp. circulating in the ticks. Because notifiable rickettsial diseases in Taiwan only include mite-borne scrub typhus and flea-borne murine typhus, more studies are warranted for a better understanding of the real extent of human risks to rickettsioses in Taiwan. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Detection of the Agent of Heartwater, Cowdria ruminantium, in Amblyomma Ticks by PCR: Validation and Application of the Assay to Field Ticks

PubMed Central

Peter, Trevor F.; Barbet, Anthony F.; Alleman, Arthur R.; Simbi, Bigboy H.; Burridge, Michael J.; Mahan, Suman M.

2000-01-01

We have previously reported that the pCS20 PCR detection assay for Cowdria ruminantium, the causative agent of heartwater disease of ruminants, is more sensitive than xenodiagnosis and the pCS20 DNA probe for the detection of infection in the vector Amblyomma ticks. Here, we further assessed the reliability of the PCR assay and applied it to field ticks. The assay detected DNA of 37 isolates of C. ruminantium originating from sites throughout the distribution of heartwater and had a specificity of 98% when infected ticks were processed concurrently with uninfected ticks. The assay did not detect DNA of Ehrlichia chaffeensis, which is closely related to C. ruminantium. PCR sensitivity varied with tick infection intensity and was high (97 to 88%) with ticks bearing 107 to 104 organisms but dropped to 61 and 28%, respectively, with ticks bearing 103 and 102 organisms. The assay also detected C. ruminantium in collections of Amblyomma hebraeum and Amblyomma variegatum field ticks from 17 heartwater-endemic sites in four southern African countries. Attempts at tick transmission of infection to small ruminants failed with four of these collections. The pCS20 PCR assay is presently the most characterized and reliable test for C. ruminantium in ticks and thus is highly useful for field and laboratory epidemiological investigations of heartwater. PMID:10747140

The diversity and prevalence of hard ticks attacking human hosts in Eastern Siberia (Russian Federation) with first description of invasion of non-endemic tick species.

PubMed

Khasnatinov, Maxim Anatolyevich; Liapunov, Alexander Valeryevich; Manzarova, Ellina Lopsonovna; Kulakova, Nina Viktorovna; Petrova, Irina Viktorovna; Danchinova, Galina Anatolyevna

2016-02-01

Hard ticks are the vectors of many pathogens including tick-borne encephalitis virus and the Lyme disease agent Borrelia burgdorferi sensu lato. In Eastern Siberia, Ixodes persulcatus, Dermacentor nuttalli, Dermacentor silvarum and Haemaphysalis concinna are regarded as aggressive to humans. Recently, significant changes in world tick fauna have been reported and this affects the spread of tick-borne pathogens. We studied the current species diversity, population structure and prevalence of tick-borne pathogens of hard ticks (Acari: Ixodidae) that attacked humans in Eastern Siberia (Irkutsk region, Russia). In total, 31,892 individual ticks were identified and analysed during the years 2007-2014. The majority (85.4%) of victims was bitten by I. persulcatus, 14.55% of attacks on humans were caused by D. nuttalli and D. silvarum, whereas H. concinna was documented only in 15 cases (0.05%). The seasonal activity and the age/gender structure of the tick population were studied as well. Among all the studied ticks, three unconventional species, i.e. Rhipicephalus sanguineus, Dermacentor reticulatus and Amblyomma americanum, were identified. Analysis of tick bite histories indicates at least three events of invasion of non-endemic ticks into the ecosystems of northern Eurasia with harsh continental climates. Invading ticks are able to reach the adult life stage and are aggressive to the local human population. Phylogenetic analysis of mt 16S rRNA gene fragments suggests multiple independent routes of tick migration to Eastern Siberia. Possible implications to human health and epidemiology of tick-borne infections are discussed.

Vector Potential and Population Dynamics for Amblyomma inornatum

PubMed Central

Medlin, Jennifer S.; Cohen, James I.; Beck, David L.

2015-01-01

We studied the natural life cycle of Amblyomma inornatum and its vector potential in South Texas. This tick is distributed throughout South Texas and most of Central America. A. inornatum represented 1.91% of the ticks collected by carbon dioxide traps during a study of free-living ticks in the Tamaulipan Biotic Province in South Texas. The life cycle of A. inornatum in South Texas showed a clear seasonal pattern consistent with one generation per year. Nymphs emerged in the spring with a peak in February through May. Adults emerged in the summer with a peak in July through September. Detection of A. inornatum larvae was negatively correlated with saturation deficit and positively correlated with rain in the previous few months. Adult activity was positively correlated with temperature and rain in the previous five weeks. Using PCR we detected the presence of species related to Candidatus Borrelia lonestari, Borrelia burgdorferi, Rickettsia species (Candidatus Rickettsia amblyommii), Ehrlichia chaffeensis, and another Ehrlichia related to Ehrlichia ewingii. Finally we sequenced the mitochondrial 16S rRNA genes and found that A. inornatum is most closely related to Amblyomma parvum. This is the first report of the life cycle, vector potential and phylogeny of A. inornatum. PMID:25881916

Genome scaffolding and annotation for the pathogen vector Ixodes ricinus by ultra-long single molecule sequencing.

PubMed

Cramaro, Wibke J; Hunewald, Oliver E; Bell-Sakyi, Lesley; Muller, Claude P

2017-02-08

Global warming and other ecological changes have facilitated the expansion of Ixodes ricinus tick populations. Ixodes ricinus is the most important carrier of vector-borne pathogens in Europe, transmitting viruses, protozoa and bacteria, in particular Borrelia burgdorferi (sensu lato), the causative agent of Lyme borreliosis, the most prevalent vector-borne disease in humans in the Northern hemisphere. To faster control this disease vector, a better understanding of the I. ricinus tick is necessary. To facilitate such studies, we recently published the first reference genome of this highly prevalent pathogen vector. Here, we further extend these studies by scaffolding and annotating the first reference genome by using ultra-long sequencing reads from third generation single molecule sequencing. In addition, we present the first genome size estimation for I. ricinus ticks and the embryo-derived cell line IRE/CTVM19. 235,953 contigs were integrated into 204,904 scaffolds, extending the currently known genome lengths by more than 30% from 393 to 516 Mb and the N50 contig value by 87% from 1643 bp to a N50 scaffold value of 3067 bp. In addition, 25,263 sequences were annotated by comparison to the tick's North American relative Ixodes scapularis. After (conserved) hypothetical proteins, zinc finger proteins, secreted proteins and P450 coding proteins were the most prevalent protein categories annotated. Interestingly, more than 50% of the amino acid sequences matching the homology threshold had 95-100% identity to the corresponding I. scapularis gene models. The sequence information was complemented by the first genome size estimation for this species. Flow cytometry-based genome size analysis revealed a haploid genome size of 2.65Gb for I. ricinus ticks and 3.80 Gb for the cell line. We present a first draft sequence map of the I. ricinus genome based on a PacBio-Illumina assembly. The I. ricinus genome was shown to be 26% (500 Mb) larger than the genome of its American relative I. scapularis. Based on the genome size of 2.65 Gb we estimated that we covered about 67% of the non-repetitive sequences. Genome annotation will facilitate screening for specific molecular pathways in I. ricinus cells and provides an overview of characteristics and functions.

Effects of conservation management of landscapes and vertebrate communities on Lyme borreliosis risk in the United Kingdom

PubMed Central

Gilbert, Lucy; Medlock, Jolyon; Hansford, Kayleigh; Thompson, Des BA; Biek, Roman

2017-01-01

Landscape change and altered host abundance are major drivers of zoonotic pathogen emergence. Conservation and biodiversity management of landscapes and vertebrate communities can have secondary effects on vector-borne pathogen transmission that are important to assess. Here we review the potential implications of these activities on the risk of Lyme borreliosis in the United Kingdom. Conservation management activities include woodland expansion, management and restoration, deer management, urban greening and the release and culling of non-native species. Available evidence suggests that increasing woodland extent, implementing biodiversity policies that encourage ecotonal habitat and urban greening can increase the risk of Lyme borreliosis by increasing suitable habitat for hosts and the tick vectors. However, this can depend on whether deer population management is carried out as part of these conservation activities. Exclusion fencing or culling deer to low densities can decrease tick abundance and Lyme borreliosis risk. As management actions often constitute large-scale perturbation experiments, these hold great potential to understand underlying drivers of tick and pathogen dynamics. We recommend integrating monitoring of ticks and the risk of tick-borne pathogens with conservation management activities. This would help fill knowledge gaps and the production of best practice guidelines to reduce risks. This article is part of the themed issue ‘Conservation, biodiversity and infectious disease: scientific evidence and policy implications’. PMID:28438912

Strain-specific antibodies reduce co-feeding transmission of the Lyme disease pathogen, Borrelia afzelii.

PubMed

Jacquet, Maxime; Durand, Jonas; Rais, Olivier; Voordouw, Maarten J

2016-03-01

Vector-borne pathogens use a diversity of strategies to evade the vertebrate immune system. Co-feeding transmission is a potential immune evasion strategy because the vector-borne pathogen minimizes the time spent in the vertebrate host. We tested whether the Lyme disease pathogen, Borrelia afzelii, can use co-feeding transmission to escape the acquired immune response in the vertebrate host. We induced a strain-specific, protective antibody response by immunizing mice with one of two variants of OspC (A3 and A10), the highly variable outer surface protein C of Borrelia pathogens. Immunized mice were challenged via tick bite with B. afzelii strains A3 or A10 and infested with larval ticks at days 2 and 34 post-infection to measure co-feeding and systemic transmission respectively. Antibodies against a particular OspC variant significantly reduced co-feeding transmission of the targeted (homologous) strain but not the non-targeted (heterologous) strain. Cross-immunity between OspC antigens had no effect in co-feeding ticks but reduced the spirochaete load twofold in ticks infected via systemic transmission. In summary, OspC-specific antibodies reduced co-feeding transmission of a homologous but not a heterologous strain of B. afzelii. Co-feeding transmission allowed B. afzelii to evade the negative consequences of cross-immunity on the tick spirochaete load. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Effects of conservation management of landscapes and vertebrate communities on Lyme borreliosis risk in the United Kingdom.

PubMed

Millins, Caroline; Gilbert, Lucy; Medlock, Jolyon; Hansford, Kayleigh; Thompson, Des Ba; Biek, Roman

2017-06-05

Landscape change and altered host abundance are major drivers of zoonotic pathogen emergence. Conservation and biodiversity management of landscapes and vertebrate communities can have secondary effects on vector-borne pathogen transmission that are important to assess. Here we review the potential implications of these activities on the risk of Lyme borreliosis in the United Kingdom. Conservation management activities include woodland expansion, management and restoration, deer management, urban greening and the release and culling of non-native species. Available evidence suggests that increasing woodland extent, implementing biodiversity policies that encourage ecotonal habitat and urban greening can increase the risk of Lyme borreliosis by increasing suitable habitat for hosts and the tick vectors. However, this can depend on whether deer population management is carried out as part of these conservation activities. Exclusion fencing or culling deer to low densities can decrease tick abundance and Lyme borreliosis risk. As management actions often constitute large-scale perturbation experiments, these hold great potential to understand underlying drivers of tick and pathogen dynamics. We recommend integrating monitoring of ticks and the risk of tick-borne pathogens with conservation management activities. This would help fill knowledge gaps and the production of best practice guidelines to reduce risks.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'. © 2017 The Authors.

Geographic Risk for Lyme Disease and Human Granulocytic Ehrlichiosis in Southern New York State†

PubMed Central

Daniels, Thomas J.; Boccia, Theresa M.; Varde, Shobha; Marcus, Jonathan; Le, Jianhua; Bucher, Doris J.; Falco, Richard C.; Schwartz, Ira

1998-01-01

Ixodes scapularis, the tick vector of Lyme disease and human granulocytic ehrlichiosis (HGE), is prevalent in much of southern New York state. The distribution of this species has increased, as have reported cases of both Lyme disease and HGE. The unreliability of case reports, however, demonstrates the need for tick and pathogen surveillance in order to accurately define areas of high risk. In this study, a total of 89,550 m2 at 34 study sites was drag sampled in 1995 and a total of 51,540 m2 at 40 sites was sampled in 1996 to determine tick and pathogen distribution in southern New York state. I. scapularis was collected from 90% of the sites sampled, and regionally, a 2.5-fold increase in nymphal abundance occurred from 1995 to 1996. I. scapularis individuals from all sites were infected with Borrelia burgdorferi in 1995, while an examination of ticks for both B. burgdorferi and the agent of HGE in 1996 confirmed that these organisms were present in all counties; the average coinfection rate was 1.9%. No correlation was found between estimated risk and reported cases of Lyme disease. The geographic disparity of risk observed among sites in this study underscores the need for vector and pathogen surveillance on a regional level. An entomologic risk index can help identify sites for targeted tick control efforts. PMID:9835546

Anchoring tick salivary anti-complement proteins IRAC I and IRAC II to membrane increases their immunogenicity

PubMed Central

Gillet, Laurent; Schroeder, Hélène; Mast, Jan; Thirion, Muriel; Renauld, Jean-Christophe; Dewals, Benjamin; Vanderplasschen, Alain

2009-01-01

Tick salivary proteins are promising targets for the development of anti-tick vaccines. Recently, we described two paralogous anti-complement proteins, called Ixodes ricinus anti-complement (IRAC) proteins I and II, that are co-expressed in tick I. ricinus salivary glands. However, our previous attempts to immunize rabbits against IRAC via infection with recombinant Bovine herpesvirus 4 (BoHV-4) vectors invariably failed although both recombinants expressed high levels of functional IRAC proteins in vitro. As IRAC are soluble monovalent antigens, one of the possible explanations is that monovalent ligation of the B-cell receptor induces receptor activation but fails to promote antigen presentation, a phenomenon that is thought to induce a state of B-cell tolerance. In the present study, we tried to increase IRAC immunogenicity by expressing them as oligovalent antigens. To this end, IRAC were fused to membrane anchors and BoHV-4 vectors expressing these recombinant forms were produced. The immunization potentials of recombinant viruses expressing either secreted or transmembrane IRAC proteins were then compared. While the former did not induce a detectable immune response against IRAC, the latter led to high titres of anti-IRAC antibodies that only marginally affected tick blood feeding. All together, the data presented in this study demonstrate that the immunogenicity of a soluble antigen can be greatly improved by anchoring it in membrane. PMID:19531344

Anchoring tick salivary anti-complement proteins IRAC I and IRAC II to membrane increases their immunogenicity.

PubMed

Gillet, Laurent; Schroeder, Hélène; Mast, Jan; Thirion, Muriel; Renauld, Jean-Christophe; Dewals, Benjamin; Vanderplasschen, Alain

2009-01-01

Tick salivary proteins are promising targets for the development of anti-tick vaccines. Recently, we described two paralogous anti-complement proteins, called Ixodes ricinus anti-complement (IRAC) proteins I and II, that are co-expressed in tick I. ricinus salivary glands. However, our previous attempts to immunize rabbits against IRAC via infection with recombinant Bovine herpesvirus 4 (BoHV-4) vectors invariably failed although both recombinants expressed high levels of functional IRAC proteins in vitro. As IRAC are soluble monovalent antigens, one of the possible explanations is that monovalent ligation of the B-cell receptor induces receptor activation but fails to promote antigen presentation, a phenomenon that is thought to induce a state of B-cell tolerance. In the present study, we tried to increase IRAC immunogenicity by expressing them as oligovalent antigens. To this end, IRAC were fused to membrane anchors and BoHV-4 vectors expressing these recombinant forms were produced. The immunization potentials of recombinant viruses expressing either secreted or transmembrane IRAC proteins were then compared. While the former did not induce a detectable immune response against IRAC, the latter led to high titres of anti-IRAC antibodies that only marginally affected tick blood feeding. All together, the data presented in this study demonstrate that the immunogenicity of a soluble antigen can be greatly improved by anchoring it in membrane.

Reviewing molecular adaptations of Lyme borreliosis spirochetes in the context of reproductive fitness in natural transmission cycles.

PubMed

Tsao, Jean I

2009-01-01

Lyme borreliosis (LB) is caused by a group of pathogenic spirochetes - most often Borrelia burgdorferi, B. afzelii, and B. garinii - that are vectored by hard ticks in the Ixodes ricinus-persulcatus complex, which feed on a variety of mammals, birds, and lizards. Although LB is one of the best-studied vector-borne zoonoses, the annual incidence in North America and Europe leads other vector-borne diseases and continues to increase. What factors make the LB system so successful, and how can researchers hope to reduce disease risk - either through vaccinating humans or reducing the risk of contacting infected ticks in nature? Discoveries of molecular interactions involved in the transmission of LB spirochetes have accelerated recently, revealing complex interactions among the spirochete-tick-vertebrate triad. These interactions involve multiple, and often redundant, pathways that reflect the evolution of general and specific mechanisms by which the spirochetes survive and reproduce. Previous reviews have focused on the molecular interactions or population biology of the system. Here molecular interactions among the LB spirochete, its vector, and vertebrate hosts are reviewed in the context of natural maintenance cycles, which represent the ecological and evolutionary contexts that shape these interactions. This holistic system approach may help researchers develop additional testable hypotheses about transmission processes, interpret laboratory results, and guide development of future LB control measures and management.

Species of ticks and carried pathogens in owned dogs in Spain: Results of a one-year national survey.

PubMed

Estrada-Peña, Agustín; Roura, Xavier; Sainz, Angel; Miró, Guadalupe; Solano-Gallego, Laia

2017-06-01

This study presents the results of a national survey in Spain on the distribution of ticks on owned dogs, their phenology and the associated pathogens over one year. In the study, 1628 adult ticks were collected on 660 dogs presented to 26 veterinary practices, of which 507 dogs (76.8%) carried at least one adult tick. The primary species of ticks were Rhipicephalus sanguineus s.l. (53%), Dermacentor reticulatus (9%), Ixodes ricinus (9%), and I. hexagonus (4%). Parasitism by two species of these ticks was rare. The four species showed a clear association with the biogeographical features of the country, with I. ricinus associated with the wettest northern regions, I. hexagonus and D. reticulatus associated with the north of the territory, and R. sanguineus s.l. prevalent throughout the entire country. Dogs living in rural areas had a higher prevalence of all species, but R. sanguineus s.l. was the most prevalent; however, this tick was also more common on dogs living indoors. R. sanguineus s.l. adults were active throughout the year, with a maximum peak from March to July. The other tick species were collected throughout the year, with an autumn-winter peak of D. reticulatus, but without clear seasonality for either I. ricinus or I. hexagonus. Combined real-time PCR and conventional PCR of the feeding ticks recorded Piroplasmida (Hepatozoon canis, Babesia canis, B. gibsoni, and several sequences compatible with Theileria spp.), Rickettsia spp. (R. massiliae, R. sibirica mongolitimonae, R. monacensis), Ehrlichia canis, Anaplasma platys, A. phagocytophilum and Borrelia spp. (B. afzelii, B. garinii, B. valaisiana). Hepatozoon canis and B. canis were the most frequently detected pathogens, with variable rates of infection according to the region. Other than a close association of Borrelia spp. with I. ricinus (and therefore to the wet northern areas of the territory), the other tick-borne pathogens were recorded throughout the country. Although a potential transmission role for ticks carrying unusual pathogens cannot be attributed to these results, these findings introduce a change of paradigm on the tick-borne pathogen distribution in Spain and emphasize the importance of performing active surveys to understand the complex patterns of tick-borne pathogen distributions and their vectors. Copyright © 2017 Elsevier GmbH. All rights reserved.

Comparison of natural and artificial odor lures for nilgai (Boselaphus tragocamelus) and white-tailed deer (Odocoileus virginianus) in South Texas: developing treatment for cattle fever tick eradication

USDA-ARS?s Scientific Manuscript database

Cattle fever ticks (CFT), vectors of bovine babesiosis and anaplasmosis, were eradicated from the United States by 1943, but are frequently reintroduced from neighboring border states of Mexico via stray cattle and wildlife hosts including white-tailed deer (Odocoileus virginianus) (WTD) and nilgai ...

Natural product studies of U.S. endangered plants: Volatile components of Lindera melissifolia (Lauraceae) repel mosquitoes and ticks

Treesearch

Joonseok Oh; John J. Bowling; John F. Carroll; Betul Demirci; K. Hüsnü Can Baser; Theodor D. Leininger; Ulrich R. Berniere; Mark T. Hamann

2012-01-01

The number of endangered plant species in the U.S. is significant, yet studies aimed towards utilizing these plants are limited. Ticks and mosquitoes are vectors of significant pathogenic diseases of humans. Repellents are critical means of personal protection against biting arthropods and disease transmission. The essential oil and solvent extracts from ...

Modelling spatial concordance between Rocky Mountain spotted fever disease incidence and habitat probability of its vector Dermacentor variabilis (American dog tick).

PubMed

Atkinson, Samuel F; Sarkar, Sahotra; Aviña, Aldo; Schuermann, Jim A; Williamson, Phillip

2012-11-01

The spatial distribution of Dermacentor variabilis, the most commonly identified vector of the bacterium Rickettsia rickettsii which causes Rocky Mountain spotted fever (RMSF) in humans, and the spatial distribution of RMSF, have not been previously studied in the south central United States of America, particularly in Texas. From an epidemiological perspective, one would tend to hypothesise that there would be a high degree of spatial concordance between the habitat suitability for the tick and the incidence of the disease. Both maximum-entropy modelling of the tick's habitat suitability and spatially adaptive filters modelling of the human incidence of RMSF disease provide reliable portrayals of the spatial distributions of these phenomenons. Even though rates of human cases of RMSF in Texas and rates of Dermacentor ticks infected with Rickettsia bacteria are both relatively low in Texas, the best data currently available allows a preliminary indication that the assumption of high levels of spatial concordance would not be correct in Texas (Kappa coefficient of agreement = 0.17). It will take substantially more data to provide conclusive findings, and to understand the results reported here, but this study provides an approach to begin understanding the discrepancy.

Ultrastructural and genetic evidence of a reptilian tick, Aponomma hydrosauri, as a host of Rickettsia honei in Australia: possible transovarial transmission.

PubMed

Whitworth, Ted; Popov, Vsevolod; Han, Violet; Bouyer, Donald; Stenos, John; Graves, Stephen; Ndip, Lucy; Walker, David

2003-06-01

In 1993, a novel rickettsia was isolated from the blood of inhabitants of Flinders Island, Australia, with acute febrile illnesses. This rickettsia was found to be a new species of spotted fever group (SFG) rickettsia, eventually named Rickettsia honei. The suspected ectoparasite vector of this rickettsia has yet to be identified. The purpose of this study was to evaluate the presence of this rickettsial species in a suspected tick vector, Aponomma hydrosauri, by DNA sequencing and electron microscopy (EM). Ticks collected from an Australian blue-tongued lizard on Flinders Island and a copperhead snake in Tasmania were demonstrated to be infected with R. honei by PCR, DNA sequencing, and EM. Rickettsiae were found in ultrathin sections of salivary glands, malpighian tubules, and midgut epithelial cells. In a previous study with a R. honei-infected tick from Flinders Island, rickettsiae were found in the nuclei of midgut epithelial cells, and EM also revealed the presence of rickettsiae in the cytosol of oocytes and immature eggs, suggesting transovarial transmission. These results implicate A. hydrosauri as a possible host of R. honei on Flinders Island and Tasmania and also provide evidence favoring transovarial maintenance of R. honei.

Vector-borne diseases on Fire Island, New York (Fire Island National Seashore Science Synthesis Paper)

USGS Publications Warehouse

Ginsberg, H.S.

2005-01-01

This paper discusses eleven tick-borne and five mosquito-borne pathogens that are known to occur at FIlS, or could potentially occur. The potential for future occurrence, and ecological factors that influence occurrence, are assessed for each disease. Lyme disease is the most common vector-borne disease on Fire Island. The Lyme spirochete, Borrelia burgdorferi, is endemic in local tick and wildlife populations. Public education, personal precautions against tick bite, and prompt treatment of early-stage infections can help manage the risk of Lyme disease on Fire Island. The pathogens that cause Human Monocytic Ehrlichiosis and Tularemia have been isolated from ticks or wildlife on Fire Island, and conditions suggest that other tickborne diseases (including Babesiosis, Rocky Mountain Spotted Fever, and Human Granulocytic Ehrlichiosis) might also occur, but these are far less common than Lyme disease, if present. West Nile Virus (WNV) is the primary mosquito- borne human pathogen that is known to occur on Fire Island. Ecological conditions and recent epizootiological events suggest that WNV occurs in foci that can shift from year to year. Therefore, a surveillance program with appropriate responses to increasing epizootic activity can help manage the risk of WNV transmission on Fire Island.

Ehrlichia phagocytophila genogroup rickettsiae in ixodid ticks from California collected in 1995 and 1996.

PubMed Central

Barlough, J E; Madigan, J E; Kramer, V L; Clover, J R; Hui, L T; Webb, J P; Vredevoe, L K

1997-01-01

A total of 1,246 ixodid ticks collected in 1995 and 1996 from seven California counties were examined for the presence of Ehrlichia phagocytophila genogroup rickettsiae by using a nested PCR technique. Of 1,112 adult Ixodes pacificus Cooley and Kohls ticks tested, nine pools, each containing five ticks, were positive (minimum percentage of ticks harboring detectable ehrlichiae, 0.8%). Positive ticks were limited to four of the seven counties (Sonoma, El Dorado, Santa Cruz, and Orange). In Santa Cruz County, three positive pools were identified at the home of an individual with prior confirmed human granulocytic ehrlichiosis. In El Dorado County, positive ticks were found at sites where cases of granulocytic ehrlichiosis in a horse and a llama had recently occurred. Among 47 nymphal I. pacificus ticks collected in Sonoma County, one positive pool was identified. Fifty-seven adult Dermacentor occidentalis Marx and 30 adult D. variabilis Say ticks, collected chiefly in southern California, were negative. These data, although preliminary, suggest that the prevalence of E. phagocytophila genogroup rickettsiae in ixodid ticks of California may be lower than in cognate vector populations (i.e., I. scapularis Say = I. dammini Spielman, Clifford, Piesman, and Corwin) in the eastern and midwestern United States. PMID:9230373

Ehrlichia phagocytophila genogroup rickettsiae in ixodid ticks from California collected in 1995 and 1996.

PubMed

Barlough, J E; Madigan, J E; Kramer, V L; Clover, J R; Hui, L T; Webb, J P; Vredevoe, L K

1997-08-01

A total of 1,246 ixodid ticks collected in 1995 and 1996 from seven California counties were examined for the presence of Ehrlichia phagocytophila genogroup rickettsiae by using a nested PCR technique. Of 1,112 adult Ixodes pacificus Cooley and Kohls ticks tested, nine pools, each containing five ticks, were positive (minimum percentage of ticks harboring detectable ehrlichiae, 0.8%). Positive ticks were limited to four of the seven counties (Sonoma, El Dorado, Santa Cruz, and Orange). In Santa Cruz County, three positive pools were identified at the home of an individual with prior confirmed human granulocytic ehrlichiosis. In El Dorado County, positive ticks were found at sites where cases of granulocytic ehrlichiosis in a horse and a llama had recently occurred. Among 47 nymphal I. pacificus ticks collected in Sonoma County, one positive pool was identified. Fifty-seven adult Dermacentor occidentalis Marx and 30 adult D. variabilis Say ticks, collected chiefly in southern California, were negative. These data, although preliminary, suggest that the prevalence of E. phagocytophila genogroup rickettsiae in ixodid ticks of California may be lower than in cognate vector populations (i.e., I. scapularis Say = I. dammini Spielman, Clifford, Piesman, and Corwin) in the eastern and midwestern United States.

Abundance of adult ticks (Acari: Ixodidae) in the Chernobyl nuclear power plant exclusion zone.

PubMed

Movila, A; Deriabina, T; Morozov, A; Sitnicova, N; Toderas, I; Uspenskaia, I; Alekhnovici, A

2012-08-01

The Chernobyl nuclear disaster resulted in contamination of vast areas in Europe. To date, there is little knowledge about the effects of radioactive contamination on tick species. We sampled ticks from vegetation and large-sized wild mammals belonging to orders Carnivora and Artiodactyla at sites with 0.76, 1.91, and 4.50 mSv/hr ionizing radiation background values in the Polesky State Radio-Ecological Reserve of the Chernobyl nuclear disaster zone in spring 2010. Altogether, 122 questing ticks were collected from vegetation. Among collected ticks, Dermacentor reticulatus (Fabricius) was, by far, the most abundant species (99.2%), followed by Ixodes ricnus (L.) (0.8%), which was collected only at the 0.76 mSv/hr site. The average sex ratio female∶male was 2.9∶1.0. In parallel with the present study, we examined 3 Sus scrofa (L.), 2 Nyctereutes procyonoides (Gray), and 1 Alces alces (L.) at the 4.50 mSv/hr site; 96 D. reticulatus ticks were found on 2 N. procyonoides specimens. The mean density and the intensity of infestation were 16 ticks per animal and 48 ticks per infested animal, respectively. Future investigations are warranted to further characterize the role of various tick vectors, vertebrate reservoirs, and diversity of tick-borne pathogens in the Chernobyl exclusion zone.

The role of rodents in the ecology of Ixodes ricinus and associated pathogens in Central and Eastern Europe.

PubMed

Mihalca, Andrei D; Sándor, Attila D

2013-01-01

Rodents comprise more species than any other mammal order. Most rodents are considered keystone species in their ecological communities, hence the survival of many other species in the ecosystem depend on them. From medical point of view, this is particularly important for rodent-dependent pathogens. In the particular case of tick-borne diseases, rodents are important as hosts for vector ticks and as reservoir hosts (Lyme borreliosis, human granulocytic anaplasmosis, Crimean-Congo hemorrhagic fever, Tick-borne relapsing fevers, tick-borne rickettsioses, babesiosis). Community and population ecology of rodents was shown to be correlated with disease ecology in the case of many tick-borne diseases. In Eastern Europe, several adult hard-tick species use rodents as their principal hosts: Ixodes apronophorus, I. crenulatus, I. laguri, I. redikorzevi, I. trianguliceps. However, the majority of ticks feeding on rodents are immature stages of ticks which as adults are parasitic on larger mammals. Larvae and nymphs of Ixodes ricinus, the most abundant and medically important tick from Europe, are commonly found on rodents. This is particularly important, as many rodents are synanthropic and, together with other micromammals and birds are often the only available natural hosts for ticks in urban environments. This work reviews the correlated ecology of rodents and I. ricinus.

Scale-dependent effects of nonnative plant invasion on host-seeking tick abundance

PubMed Central

Adalsteinsson, Solny A.; D’Amico, Vincent; Shriver, W. Gregory; Brisson, Dustin; Buler, Jeffrey J.

2016-01-01

Nonnative, invasive shrubs can affect human disease risk through direct and indirect effects on vector populations. Multiflora rose (Rosa multiflora) is a common invader within eastern deciduous forests where tick-borne disease (e.g. Lyme disease) rates are high. We tested whether R. multiflora invasion affects blacklegged tick (Ixodes scapularis) abundance, and at what scale. We sampled host-seeking ticks at two spatial scales: fine-scale, within R. multiflora-invaded forest fragments; and patch scale, among R. multiflora-invaded and R. multiflora-free forest fragments. At a fine scale, we trapped 2.3 times more ticks under R. multiflora compared to paired traps 25 m away from R. multiflora. At the patch scale, we trapped 3.2 times as many ticks in R. multiflora-free forests compared to R. multiflora-invaded forests. Thus, ticks are concentrated beneath R. multiflora within invaded forests, but uninvaded forests support significantly more ticks. Among all covariates tested, leaf litter volume was the best predictor of tick abundance; at the patch scale, R. multiflora-invaded forests had less leaf litter than uninvaded forests. We suggest that leaf litter availability at the patch-scale plays a greater role in constraining tick abundance than the fine-scale, positive effect of invasive shrubs. PMID:27088044

Amblyomma maculatum SECIS binding protein 2 and putative selenoprotein P are indispensable for pathogen replication and tick fecundity.

PubMed

Budachetri, Khemraj; Crispell, Gary; Karim, Shahid

2017-09-01

Selenium, a vital trace element, is incorporated into selenoproteins to produce selenocysteine. Our previous studies have revealed an adaptive co-evolutionary process that has enabled the spotted fever-causing tick-borne pathogen Rickettsia parkeri to survive by manipulating an antioxidant defense system associated with selenium, which includes a full set of selenoproteins and other antioxidants in ticks. Here, we conducted a systemic investigation of SECIS binding protein 2 (SBP2) and putative selenoprotein P (SELENOP) by transcript silencing in adult female Gulf-coast ticks (Amblyomma maculatum). Knockdown of the SBP2 and SELENOP genes depleted the respective transcript levels of these tick selenogenes, and caused differential regulation of other antioxidants. Importantly, the selenium level in the immature and mature tick stages increased significantly after a blood meal, but the selenium level decreased in ticks after the SBP2 and SELENOP knockdowns. Moreover, the SBP2 knockdown significantly impaired both transovarial transmission of R. parkeri to tick eggs and egg hatching. Overall, our data offer new insight into the relationship between the SBP2 selenoprotein synthesis gene and the putative tick SELENOP gene. It also augments our understanding of selenoprotein synthesis, selenium maintenance and utilization, and bacterial colonization of a tick vector. Copyright © 2017 Elsevier Ltd. All rights reserved.

Different Ecological Niches for Ticks of Public Health Significance in Canada

PubMed Central

Gabriele-Rivet, Vanessa; Arsenault, Julie; Badcock, Jacqueline; Cheng, Angela; Edsall, Jim; Goltz, Jim; Kennedy, Joe; Lindsay, L. Robbin; Pelcat, Yann; Ogden, Nicholas H.

2015-01-01

Tick-borne diseases are a growing public health concern as their incidence and range have increased in recent decades. Lyme disease is an emerging infectious disease in Canada due to northward expansion of the geographic range of Ixodes scapularis, the principal tick vector for the Lyme disease agent Borrelia burgdorferi, into central and eastern Canada. In this study the geographical distributions of Ixodid ticks, including I. scapularis, and environmental factors associated with their occurrence were investigated in New Brunswick, Canada, where few I. scapularis populations have been found to date. Density of host-seeking ticks was evaluated by drag sampling of woodland habitats in a total of 159 sites. Ixodes scapularis ticks (n = 5) were found on four sites, Ixodes muris (n = 1) on one site and Haemaphysalis leporispalustris (n = 243) on 41 sites. One of four adult I. scapularis ticks collected was PCR-positive for B. burgdorferi. No environmental variables were significantly associated with the presence of I. scapularis although comparisons with surveillance data in neighbouring provinces (Québec and Nova Scotia) suggested that temperature conditions may be too cold for I. scapularis (< 2800 annual degree days above 0°C [DD > 0°C]) across much of New Brunswick. In contrast, the presence of H. leporispalustris, which is a competent vector of tularaemia, was significantly (P < 0.05) associated with specific ranges of mean DD > 0°C, mean annual precipitation, percentage of clay in site soil, elevation and season in a multivariable logistic regression model. With the exception of some localized areas, temperature conditions and deer density may be too low for the establishment of I. scapularis and Lyme disease risk areas in New Brunswick, while environmental conditions were suitable for H. leporispalustris at many sites. These findings indicate differing ecological niches for two tick species of public health significance. PMID:26131550

Different Ecological Niches for Ticks of Public Health Significance in Canada.

PubMed

Gabriele-Rivet, Vanessa; Arsenault, Julie; Badcock, Jacqueline; Cheng, Angela; Edsall, Jim; Goltz, Jim; Kennedy, Joe; Lindsay, L Robbin; Pelcat, Yann; Ogden, Nicholas H

2015-01-01

Tick-borne diseases are a growing public health concern as their incidence and range have increased in recent decades. Lyme disease is an emerging infectious disease in Canada due to northward expansion of the geographic range of Ixodes scapularis, the principal tick vector for the Lyme disease agent Borrelia burgdorferi, into central and eastern Canada. In this study the geographical distributions of Ixodid ticks, including I. scapularis, and environmental factors associated with their occurrence were investigated in New Brunswick, Canada, where few I. scapularis populations have been found to date. Density of host-seeking ticks was evaluated by drag sampling of woodland habitats in a total of 159 sites. Ixodes scapularis ticks (n = 5) were found on four sites, Ixodes muris (n = 1) on one site and Haemaphysalis leporispalustris (n = 243) on 41 sites. One of four adult I. scapularis ticks collected was PCR-positive for B. burgdorferi. No environmental variables were significantly associated with the presence of I. scapularis although comparisons with surveillance data in neighbouring provinces (Québec and Nova Scotia) suggested that temperature conditions may be too cold for I. scapularis (< 2800 annual degree days above 0°C [DD > 0°C]) across much of New Brunswick. In contrast, the presence of H. leporispalustris, which is a competent vector of tularaemia, was significantly (P < 0.05) associated with specific ranges of mean DD > 0°C, mean annual precipitation, percentage of clay in site soil, elevation and season in a multivariable logistic regression model. With the exception of some localized areas, temperature conditions and deer density may be too low for the establishment of I. scapularis and Lyme disease risk areas in New Brunswick, while environmental conditions were suitable for H. leporispalustris at many sites. These findings indicate differing ecological niches for two tick species of public health significance.

Variation in the Microbiota of Ixodes Ticks with Regard to Geography, Species, and Sex

PubMed Central

Van Treuren, Will; Ponnusamy, Loganathan; Brinkerhoff, R. Jory; Gonzalez, Antonio; Parobek, Christian M.; Juliano, Jonathan J.; Andreadis, Theodore G.; Falco, Richard C.; Ziegler, Lorenza Beati; Hathaway, Nicholas; Keeler, Corinna; Emch, Michael; Bailey, Jeffrey A.; Roe, R. Michael; Apperson, Charles S.; Knight, Rob

2015-01-01

Ixodes scapularis is the principal vector of Lyme disease on the East Coast and in the upper Midwest regions of the United States, yet the tick is also present in the Southeast, where Lyme disease is absent or rare. A closely related species, I. affinis, also carries the pathogen in the South but does not seem to transmit it to humans. In order to better understand the geographic diversity of the tick, we analyzed the microbiota of 104 adult I. scapularis and 13 adult I. affinis ticks captured in 19 locations in South Carolina, North Carolina, Virginia, Connecticut, and New York. Initially, ticks from 4 sites were analyzed by 454 pyrosequencing. Subsequently, ticks from these sites plus 15 others were analyzed by sequencing with an Illumina MiSeq machine. By both analyses, the microbiomes of female ticks were significantly less diverse than those of male ticks. The dissimilarity between tick microbiomes increased with distance between sites, and the state in which a tick was collected could be inferred from its microbiota. The genus Rickettsia was prominent in all locations. Borrelia was also present in most locations and was present at especially high levels in one site in western Virginia. In contrast, members of the family Enterobacteriaceae were very common in North Carolina I. scapularis ticks but uncommon in I. scapularis ticks from other sites and in North Carolina I. affinis ticks. These data suggest substantial variations in the Ixodes microbiota in association with geography, species, and sex. PMID:26150449

Ixodes ricinus and Its Transmitted Pathogens in Urban and Peri-Urban Areas in Europe: New Hazards and Relevance for Public Health

PubMed Central

Rizzoli, Annapaola; Silaghi, Cornelia; Obiegala, Anna; Rudolf, Ivo; Hubálek, Zdeněk; Földvári, Gábor; Plantard, Olivier; Vayssier-Taussat, Muriel; Bonnet, Sarah; Špitalská, Eva; Kazimírová, Mária

2014-01-01

Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, “Candidatus Neoehrlichia mikurensis,” Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases. PMID:25520947

Etiological [corrected] agents of rickettsiosis and anaplasmosis in ticks collected in Emilia-Romagna region (Italy) during 2008 and 2009.

PubMed

Maioli, Giulia; Pistone, Dario; Bonilauri, Paolo; Pajoro, Massimo; Barbieri, Ilaria; Mulatto, Patrizia; Patrizia, Mulatto; Vicari, Nadia; Dottori, Michele

2012-06-01

Ticks are the main vectors of rickettsiae of the spotted fever group, as well as of a variety of other Rickettsiales, including bacteria of the genus Anaplasma, that might cause diseases in humans and animals. Here we present the result of a survey for ticks and for tick-associated Rickettsiales in the Emilia Romagna region (Northern Italy). The study was focused on ticks collected from wild-hunted animals. Out of 392 ticks collected from these animals, 282 (72%) were identified as Ixodes ricinus, 110 (28%) as Dermacentor marginatus. The former was found on four vertebrate species, whereas the latter appeared more specific for wild boar. The presence of rickettsiae was demonstrated in 22.5% of I. ricinus (57/253) and in 29% of D. marginatus (32/110). Five ticks of the species I. ricinus were also positive for Anaplasma phagocytophilum (2%). In addition, we collected ticks by dragging in a natural park of the same region. All of the ticks captured by dragging were identified as I. ricinus. Thirty-six out of 200 analyzed ticks proved positive for Rickettsia monacensis and R. helvetica (16.5 and 1.5%, respectively). Our results highlight that that ticks present in wild areas, widely exploited for recreation and hunting in Emilia-Romagna, represent a risk for the transmission of spotted fevers and anaplasmosis to humans.

Molecular detection of Crimean-Congo haemorrhagic fever (CCHF) virus in ticks from southeastern Iran.

PubMed

Mehravaran, Ahmad; Moradi, Maryam; Telmadarraiy, Zakyeh; Mostafavi, Ehsan; Moradi, Ali Reza; Khakifirouz, Sahar; Shah-Hosseini, Nariman; Varaie, Fereshteh Sadat Rasi; Jalali, Tahmineh; Hekmat, Soheila; Ghiasi, Seyed Mojtaba; Chinikar, Sadegh

2013-02-01

Crimean-Congo haemorrhagic fever (CCHF) virus is a tick-borne member of the genus Nairovirus, family Bunyaviridae. CCHF virus has been isolated from at least 31 different species of ticks. The virus is transmitted through the bite of an infected tick or by direct contact with CCHF virus-infected patients or the products of infected livestock. This study was conducted to determine the rate of CCHF virus infection in ticks in the district of Zahedan, in the province of Sistan and Baluchistan, southeastern Iran. A total of 140 ticks were collected from Sistan and Baluchistan. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used for the detection of the CCHF virus genome in the tick population. This genome was detected in 4.3% of ticks collected from livestock of different regions of Zahedan. The infected tick genera belonged to Hyalomma and Haemaphysalis. Although in the epidemiology of CCHF virus Hyalomma ticks are considered to be the most important vectors and reservoirs, the virus has also been reported to occur in other genera of ticks, which conforms to the current data in our study from Sistan and Baluchistan. Given that animals are common hosts for Hyalomma and Haemaphysalis, regular monitoring programmes for livestock should be applied for CCHF virus control. Copyright © 2012 Elsevier GmbH. All rights reserved.

Reservoir targeted vaccine for lyme borreliosis induces a yearlong, neutralizing antibody response to OspA in white-footed mice.

PubMed

Meirelles Richer, Luciana; Aroso, Miguel; Contente-Cuomo, Tania; Ivanova, Larisa; Gomes-Solecki, Maria

2011-11-01

Lyme disease is caused by the spirochete Borrelia burgdorferi. The enzootic cycle of this pathogen requires that Ixodes spp. acquire B. burgdorferi from infected wildlife reservoirs and transmit it to other uninfected wildlife. At present, there are no effective measures to control B. burgdorferi; there is no human vaccine available, and existing vector control measures are generally not acceptable to the public. However, if B. burgdorferi could be eliminated from its reservoir hosts or from the ticks that feed on them, the enzootic cycle would be broken, and the incidence of Lyme disease would decrease. We developed OspA-RTV, a reservoir targeted bait vaccine (RTV) based on the immunogenic outer surface protein A (OspA) of B. burgdorferi aimed at breaking the natural cycle of this spirochete. White-footed mice, the major reservoir species for this spirochete in nature developed a systemic OspA-specific IgG response as a result of ingestion of the bait formulation. This immune response protected white-footed mice against B. burgdorferi infection upon tick challenge and cleared B. burgdorferi from the tick vector. In performing extensive studies to optimize the OspA-RTV for field deployment, we determined that mice that consumed the vaccine over periods of 1 or 4 months developed a yearlong, neutralizing anti-OspA systemic IgG response. Furthermore, we defined the minimum number of OspA-RTV units needed to induce a protective immune response.

Prevention of vector transmitted diseases with clove oil insect repellent.

PubMed

Shapiro, Rochel

2012-08-01

Vector repellent is one element in the prevention of vector-borne diseases. Families that neglect protecting their children against vectors risk their children contracting illnesses such as West Nile virus, eastern equine encephalitis, Lyme disease, malaria, dengue hemorrhagic fever, yellow fever, babesiosis, Crimean-Congo hemorrhagic fever, Rocky Mountain spotted fever, Southern tick-associated rash illness, ehrlichiosis, tick-borne relapsing fever, tularemia, and other insect and arthropod related diseases (CDC, 2011). Identification of families at risk includes screening of the underlying basis for reluctance to apply insect repellent. Nurses and physicians can participate in a positive role by assisting families to determine the proper prophylaxis by recommending insect repellent choices that are economical, safe, and easy to use. A holistic alternative might include the suggestion of clove oil in cases where families might have trepidations regarding the use of DEET on children. This article will explore the safety and effectiveness of clove oil and its use as an insect repellent. Copyright © 2012 Elsevier Inc. All rights reserved.

Genomic Characterization of Crimean-Congo Hemorrhagic Fever Virus in Hyalomma Tick from Spain, 2014.

PubMed

Cajimat, Maria N B; Rodriguez, Sergio E; Schuster, Isolde U E; Swetnam, Daniele M; Ksiazek, Thomas G; Habela, Miguel A; Negredo, Ana Isabel; Estrada-Peña, Agustín; Barrett, Alan D T; Bente, Dennis A

2017-10-01

Crimean-Congo hemorrhagic fever (CCHF) is a severe tick-borne disease caused by CCHF virus (CCHFV). Ticks in the genus Hyalomma are the main vectors and reservoirs of CCHFV. In Spain, CCHFV was first detected in Hyalomma ticks from Cáceres in 2010. Subsequently, two autochthonous CCHF cases were reported in August 2016. In this study, we describe the characterization of the CCHFV genome directly from Hyalomma lusitanicum collected in Cáceres in 2014. Phylogenetic analyses reveal a close relationship with clade III strains from West Africa, with an estimated divergence time of 50 years. The results of this work suggest that CCHFV has been circulating in Spain for some time, and most likely originated from West Africa.

Five cases of vector-borne Francisella tularensis holarctica infections in south-western Germany and genetic diversity.

PubMed

Borde, Johannes P; Zange, Sabine; Antwerpen, Markus H; Georgi, Enrico; von Buttlar, Heiner; Kern, Winfried V; Rieg, Siegbert

2017-08-01

Tularemia is a rare zoonotic disease in Germany. Francisella tularensis has been isolated previously from ticks in southern Germany underscoring the importance of ticks (Ixodes ricinus) in tularemia transmission, but there have been only few reports from this region with single cases or small case series of tick-borne transmissions of tularemia. We report five cases of non-game animal associated tularemia diagnosed from 2010 to 2016 in southwestern Germany - Baden-Wuerttemberg. Our case series and molecular typing (MLVA) results add published clinical experience to this underdiagnosed disease and consolidate previous findings regarding tick-borne transmission of tularemia and phylogenetic diversity in Germany. Copyright © 2017 Elsevier GmbH. All rights reserved.

Host surveys, ixodid tick biology and transmission scenarios as related to the tick-borne pathogen, Ehrlichia canis

PubMed Central

Stich, R. W.; Schaefer, John J.; Bremer, William G.; Needham, Glen R.; Jittapalapong, Sathaporn

2008-01-01

The ehrlichioses have been subject to increasing interest from veterinary and public health perspectives, but experimental studies of these diseases and their etiologic agents can be challenging. Ehrlichia canis, the primary etiologic agent of canine monocytic ehrlichiosis, is relatively well characterized and offers unique advantages and opportunities to study interactions between a monocytotropic pathogen and both its vertebrate and invertebrate hosts. Historically, advances in tick-borne disease control strategies have typically followed explication of tick-pathogen-vertebrate interactions, thus it is reasonable to expect novel, more sustainable approaches to control of these diseases as the transmission of their associated infections are investigated at the molecular through ecological levels. Better understanding of the interactions between E. canis and its canine and tick hosts would also elucidate similar interactions for other Ehrlichia species as well as the potential roles of canine sentinels, reservoirs and models of tick-borne zoonoses. This article summarizes natural exposure studies and experimental investigations of E. canis in the context of what is understood about biological vectors of tick-borne Anaplasmataceae. PMID:18963493

General framework for comparative quantitative studies on transmission of tick-borne diseases using Lyme borreliosis in Europe as an example.

PubMed

Randolph, S E; Craine, N G

1995-11-01

Models of tick-borne diseases must take account of the particular biological features of ticks that contrast with those of insect vectors. A general framework is proposed that identifies the parameters of the transmission dynamics of tick-borne diseases to allow a quantitative assessment of the relative contributions of different host species and alternative transmission routes to the basic reproductive number, Ro, of such diseases. Taking the particular case of the transmission of the Lyme borreliosis spirochaete, Borrelia burgdorferi, by Ixodes ticks in Europe, and using the best, albeit still inadequate, estimates of the parameter values and a set of empirical data from Thetford Forest, England, we show that squirrels and the transovarial transmission route make quantitatively very significant contributions to Ro. This approach highlights the urgent need for more robust estimates of certain crucial parameter values, particularly the coefficients of transmission between ticks and vertebrates, before we can progress to full models that incorporate seasonality and heterogeneity among host populations for the natural dynamics of transmission of borreliosis and other tick-borne diseases.

Distribution and host associations of ixodid ticks collected from wildlife in Florida, USA.

PubMed

Hertz, Jeffrey C; Ferree Clemons, Bambi C; Lord, Cynthia C; Allan, Sandra A; Kaufman, Phillip E

2017-10-01

A tick survey was conducted to document tick-host associations with Florida (USA) wildlife, and to determine the relative abundance and distribution of ixodid ticks throughout the state. The survey was conducted using collection kits distributed to licensed Florida hunters as well as the examination of archived specimens from ongoing state wildlife research programs. Collected tick samples were obtained from 66% of Florida counties and were collected from nine wildlife hosts, including black bear, bobcat, coyote, deer, gray fox, Florida panther, raccoon, swine, and wild turkey. In total, 4176 ticks were identified, of which 75% were Amblyomma americanum, 14% Ixodes scapularis, 8% A. maculatum, 3% Dermacentor variabilis, and < 1% were I. affinis and I. texanus. americanum, D. variabilis, and I. scapularis had the broadest host range, while A. maculatum, D. variabilis, and I. scapularis had the widest geographic distribution. While the survey data contribute to an understanding of tick-host associations in Florida, they also provide insight into the seasonal and geographic distribution of several important vector species in the southeastern USA.

Assessment of bacterial diversity in Hyalomma aegyptium, H. marginatum and H. excavatum ticks through tag-encoded pyrosequencing.

PubMed

Keskin, Adem; Bursali, Ahmet; Snow, David E; Dowd, Scot E; Tekin, Saban

2017-12-01

Ticks are among the most significant human-biting ectoparasites and they play a major role in transmission of many pathogenic agents to humans. In the present study, three species of Hyalomma ticks, Hyalomma aegyptium, H. marginatum and H. excavatum, were examined for the presence of zoonotic bacteria, both male and female ticks alike. Examination of microbial diversity with tag-encoded pyrosequencing indicates that H. marginatum and H. excavatum were more diversity rich than H. aegyptium. Although numerous pathogenic and non-pathogenic bacterial genera were detected, including Acidovorax, Bacillus, Bacteroides, Bdellovibrio, Clostridium, Curvibacter, Escherichia, Flavobacterium, Limnohabitans, Paenibacillus, Ralstonia, Sarcina, Sediminibacterium, Segetibacter Stenotrophomonas and Variovorax, the predominant zoonotic bacteria represented in these ticks were genera Borrelia, Francisella, and Rickettsia. To the authors' knowledge, this work represents the first detection of Yersinia enterocolitica in the tick H. excavatum, raising questions regarding the vector competency of this tick, as well as associations of different disease representations perhaps through previously unforeseen routes of pathogen introduction. Likewise, similar questions are related to the presence of Legionella pneumophila in one H. excavatum sample.

Role of Grooming in Reducing Tick Load in Wild Baboons (Papio cynocephalus)

PubMed Central

Akinyi, Mercy Y.; Tung, Jenny; Jeneby, Maamun; Patel, Nilesh B.; Altmann, Jeanne; Alberts, Susan C.

2013-01-01

Nonhuman primate species spend a conspicuous amount of time grooming during social interactions, a behavior that probably serves both social and health-related functions. While the social implications of grooming have been relatively well studied, less attention has been paid to the health benefits, especially the removal of ectoparasites, which may act as vectors in disease transmission. In this study, we examined the relationship between grooming behavior, tick load (number of ticks), and haemoprotozoan infection status in a population of wild free-ranging baboons (Papio cynocephalus). We found that the amount of grooming received was influenced by an individual’s age, sex and dominance rank. The amount of grooming received, in turn, affected the tick load of an individual. Baboons with higher tick loads had lower packed red cell volume (PCV or haematocrit), one general measure of health status. We detected a tick-borne haemoprotozoan, Babesia microti, but its low prevalence in the population precluded identifying sources of variance in infection. PMID:24659824

MicroRNA-275 and its target Vitellogenin-2 are crucial in ovary development and blood digestion of Haemaphysalis longicornis.

PubMed

Hao, Jiawei; Luo, Jin; Chen, Ze; Ren, Qiaoyun; Guo, Jinxia; Liu, Xiaocui; Chen, Qiuyu; Wu, Feng; Wang, Zhen; Luo, Jianxun; Yin, Hong; Wang, Hui; Liu, Guangyuan

2017-05-22

The hard tick Haemaphysalis longicornis is widely distributed in eastern Asia, New Zealand and Australia and is considered the major vector of Theileria and Babesia, harmful parasites to humans and animals. Female ticks need successful blood meals to complete the life-cycle. Therefore, elucidation of the underlying molecular mechanisms of H. longicornis development and reproduction is considered important for developing control strategies against the tick and tick-borne pathogens. Luciferase assays were used to identify the targets of micro RNA miR-275 in vitro. RNAi of Vitellogenin (Vg) was used in phenotype rescue experiments of ticks with miR-275 inhibition, and these analyses were used to identify the authentic target of miR-275 in vivo. The expression of miR-275 in different tissues and developmental stages of ticks was assessed by real-time PCR. To elucidate the functions of miR-275 in female ticks, we injected a miR-275 antagomir into female ticks and observed the phenotypic changes. Statistical analyses were performed with GraphPad5 using Student's t-test. In this study, we identified Vg-2 as an authentic target of miR-275 both in vitro and in vivo by luciferase assays and phenotype rescue experiments. miR-275 plays the regulatory role in a tissue-specific manner and differentially in developmental stages. Silencing of miR-275 resulted in blood digestion problems, substantially impaired ovary development and significantly reduced egg mass (P < 0.0001). Furthermore, RNAi silencing of Vg-2 not only impacted the blood meal uptake (P < 0.05) but also the egg mass (P < 0.05). Significant rescue was observed in miR-275 knockout ticks when RNAi was applied to Vg-2. To our knowledge, this study is the first demonstration that miR-275 targets Vg-2 in H. longicornis and regulates the functions of blood digestion and ovary development. These findings improve the molecular understanding of tick development and reproduction.

Analysis of the Salivary Gland Transcriptome of Unfed and Partially Fed Amblyomma sculptum Ticks and Descriptive Proteome of the Saliva

PubMed Central

Esteves, Eliane; Maruyama, Sandra R.; Kawahara, Rebeca; Fujita, André; Martins, Larissa A.; Righi, Adne A.; Costa, Francisco B.; Palmisano, Giuseppe; Labruna, Marcelo B.; Sá-Nunes, Anderson; Ribeiro, José M. C.; Fogaça, Andréa C.

2017-01-01

Ticks are obligate blood feeding ectoparasites that transmit a wide variety of pathogenic microorganisms to their vertebrate hosts. Amblyomma sculptum is vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever (RMSF), the most lethal rickettsiosis that affects humans. It is known that the transmission of pathogens by ticks is mainly associated with the physiology of the feeding process. Pathogens that are acquired with the blood meal must first colonize the tick gut and later the salivary glands (SG) in order to be transmitted during a subsequent blood feeding via saliva. Tick saliva contains a complex mixture of bioactive molecules with anticlotting, antiplatelet aggregation, vasodilatory, anti-inflammatory, and immunomodulatory properties to counteract both the hemostasis and defense mechanisms of the host. Besides facilitating tick feeding, the properties of saliva may also benefits survival and establishment of pathogens in the host. In the current study, we compared the sialotranscriptome of unfed A. sculptum ticks and those fed for 72 h on rabbits using next generation RNA sequencing (RNA-seq). The total of reads obtained were assembled in 9,560 coding sequences (CDSs) distributed in different functional classes. CDSs encoding secreted proteins, including lipocalins, mucins, protease inhibitors, glycine-rich proteins, metalloproteases, 8.9 kDa superfamily members, and immunity-related proteins were mostly upregulated by blood feeding. Selected CDSs were analyzed by real-time quantitative polymerase chain reaction preceded by reverse transcription (RT-qPCR), corroborating the transcriptional profile obtained by RNA-seq. Finally, high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis revealed 124 proteins in saliva of ticks fed for 96–120 h. The corresponding CDSs of 59 of these proteins were upregulated in SG of fed ticks. To the best of our knowledge, this is the first report on the proteome of A. sculptum saliva. The functional characterization of the identified proteins might reveal potential targets to develop vaccines for tick control and/or blocking of R. rickettsii transmission as well as pharmacological bioproducts with antihemostatic, anti-inflammatory and antibacterial activities. PMID:29209593

The Tick Cell Biobank: A global resource for in vitro research on ticks, other arthropods and the pathogens they transmit.

PubMed

Bell-Sakyi, Lesley; Darby, Alistair; Baylis, Matthew; Makepeace, Benjamin L

2018-05-31

Tick cell lines are increasingly used in many fields of tick and tick-borne disease research. The Tick Cell Biobank was established in 2009 to facilitate the development and uptake of these unique and valuable resources. As well as serving as a repository for existing and new ixodid and argasid tick cell lines, the Tick Cell Biobank supplies cell lines and training in their maintenance to scientists worldwide and generates novel cultures from tick species not already represented in the collection. Now part of the Institute of Infection and Global Health at the University of Liverpool, the Tick Cell Biobank has embarked on a new phase of activity particularly targeted at research on problems caused by ticks, other arthropods and the diseases they transmit in less-developed, lower- and middle-income countries. We are carrying out genotypic and phenotypic characterisation of selected cell lines derived from tropical tick species. We continue to expand the culture collection, currently comprising 63 cell lines derived from 18 ixodid and argasid tick species and one each from the sand fly Lutzomyia longipalpis and the biting midge Culicoides sonorensis, and are actively engaging with collaborators to obtain starting material for primary cell cultures from other midge species, mites, tsetse flies and bees. Outposts of the Tick Cell Biobank will be set up in Malaysia, Kenya and Brazil to facilitate uptake and exploitation of cell lines and associated training by scientists in these and neighbouring countries. Thus the Tick Cell Biobank will continue to underpin many areas of global research into biology and control of ticks, other arthropods and vector-borne viral, bacterial and protozoan pathogens. Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

Endemic Scrub Typhus-like Illness, Chile

DTIC Science & Technology

2011-09-01

from Asia. The primary hosts for Rickettsia species are arthropods that can also act as disease vectors for humans and other vertebrates. Ticks...are vectors for most rickettsioses caused by spotted fever group rickettsiae . Alternative vectors for rickettsiae are well known, including fl eas as...sample recovered from a paraffi n- embedded sample for electron microscopy, showed round and oval rickettsia -like microorganisms, maximum diameter

Superinfection exclusion of the ruminant pathogen anaplasma marginale in the tick vector is dependent on time between exposures to the strains

USDA-ARS?s Scientific Manuscript database

The remarkable genetic diversity of vector-borne pathogens allows for the establishment of superinfection in the mammalian host. To have a long-term impact on population strain structure, the introduced strains must also be transmitted by a vector population that has been exposed to the existing pri...

Tick salivary secretion as a source of antihemostatics

PubMed Central

Chmelar, Jindrich; Calvo, Eric; Pedra, Joao H.F.; Francischetti, Ivo M. B.; Kotsyfakis, Michail

2012-01-01

Ticks are mostly obligatory blood feeding ectoparasites that have an impact on human and animal health. In addition to direct damage due to feeding, some tick species serve as the vectors for the causative agents of several diseases, such as the spirochetes of the genus Borrelia causing Lyme disease, the virus of tick-borne encephalitis, various Rickettsial pathogens or even protozoan parasites like Babesia spp. Hard ticks are unique among bloodfeeders because of their prolonged feeding period that may last up to two weeks. During such a long period of blood uptake, the host develops a wide range of mechanisms to prevent blood loss. The arthropod ectoparasite, in turn, secretes saliva in the sites of bite that assists blood feeding. Indeed, tick saliva represents a rich source of proteins with potent pharmacologic action that target different mechanisms of coagulation, platelet aggregation and vasoconstriction. Tick adaptation to their vertebrate hosts led to the inclusion of a powerful protein armamentarium in their salivary secretion that has been investigated by high throughput methods. The resulting knowledge can be exploited for the isolation of novel antihemostatic agents. Here we review the tick salivary antihemostatics and their characterized functions at the molecular and cellular levels. PMID:22564820

Flavivirus Infection of Ixodes scapularis (Black-Legged Tick) Ex Vivo Organotypic Cultures and Applications for Disease Control.

PubMed

Grabowski, Jeffrey M; Tsetsarkin, Konstantin A; Long, Dan; Scott, Dana P; Rosenke, Rebecca; Schwan, Tom G; Mlera, Luwanika; Offerdahl, Danielle K; Pletnev, Alexander G; Bloom, Marshall E

2017-08-22

Ixodes scapularis ticks transmit many infectious agents that cause disease, including tick-borne flaviviruses (TBFVs). TBFV infections cause thousands of human encephalitis cases worldwide annually. In the United States, human TBFV infections with Powassan virus (POWV) are increasing and have a fatality rate of 10 to 30%. Additionally, Langat virus (LGTV) is a TBFV of low neurovirulence and is used as a model TBFV. TBFV replication and dissemination within I. scapularis organs are poorly characterized, and a deeper understanding of virus biology in this vector may inform effective countermeasures to reduce TBFV transmission. Here, we describe short-term, I. scapularis organ culture models of TBFV infection. Ex vivo organs were metabolically active for 9 to 10 days and were permissive to LGTV and POWV replication. Imaging and videography demonstrated replication and spread of green fluorescent protein-expressing LGTV in the organs. Immunohistochemical staining confirmed LGTV envelope and POWV protein synthesis within the infected organs. LGTV- and POWV-infected organs produced infectious LGTV and POWV; thus, the ex vivo cultures were suitable for study of virus replication in individual organs. LGTV- and POWV-infected midgut and salivary glands were subjected to double-stranded RNA (dsRNA) transfection with dsRNA to the LGTV 3' untranslated region (UTR), which reduced infectious LGTV and POWV replication, providing a proof-of-concept use of RNA interference in I. scapularis organ cultures to study the effects on TBFV replication. The results contribute important information on TBFV localization within ex vivo I. scapularis organs and provide a significant translational tool for evaluating recombinant, live vaccine candidates and potential tick transcripts and proteins for possible therapeutic use and vaccine development to reduce TBFV transmission. IMPORTANCE Tick-borne flavivirus (TBFV) infections cause neurological and/or hemorrhagic disease in humans worldwide. There are currently no licensed therapeutics or vaccines against Powassan virus (POWV), the only TBFV known to circulate in North America. Evaluating tick vector targets for antitick vaccines directed at reducing TBFV infection within the arthropod vector is a critical step in identifying efficient approaches to controlling TBFV transmission. This study characterized infection of female Ixodes scapularis tick organ cultures of midgut, salivary glands, and synganglion with the low-neurovirulence Langat virus (LGTV) and the more pathogenic POWV. Cell types of specific organs were susceptible to TBFV infection, and a difference in LGTV and POWV replication was noted in TBFV-infected organs. This tick organ culture model of TBFV infection will be useful for various applications, such as screening of tick endogenous dsRNA corresponding to potential control targets within midgut and salivary glands to confirm restriction of TBFV infection.

Climatic factors in resurgence of Mediterranean spotted fever

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arenas, E.E.; Creus, B.F.; Cueto, F.B.

1986-06-07

There has been a recent resurgence of Mediterranean spotted fever in areas bordering the Mediterranean Sea. This disease is caused by Rickettsia conorii, the dog tick being the vector and main reservoir. Ticks prefer warm weather and their activity increases with rising temperature. In the Valles Occidental, Spain, the incidence of the disease is correlated with hotter and drier summers in the past ten years.

North American soft ticks (Ornithodoros spp.): biology and feral swine parasitism as risks for the emergence of African swine fever in the U.S.A.

USDA-ARS?s Scientific Manuscript database

African Swine Fever (ASF) is an emerging arboviral disease that affects pigs. The causative agent is the double-stranded DNA African Swine Fever Virus (ASFV). Several soft tick species in the genus Ornithodoros are known arthropod vectors of ASFV. Infection with ASFV can result in a hemorrhagic synd...

Tick-borne diseases and autoimmunity: A comprehensive review.

PubMed

Rodríguez, Yhojan; Rojas, Manuel; Gershwin, M Eric; Anaya, Juan-Manuel

2018-03-01

Tick-borne diseases (TBDs) are emerging and reemerging diseases transmitted by ticks, which portray wide heterogeneity and global distribution. TBDs may present acute clinical pictures that resemble those of autoimmune diseases (i.e., musculoskeletal symptoms, cutaneous involvement, neurologic impairment, renal failure, etc.), and in some cases infection is considered a triggering factor for autoimmunity (e.g., rheumatoid arthritis, autoimmune thyroid disease, vasculitides). The clinician should consider TBDs among the differential diagnoses when approaching autoimmune-like signs in areas of tick infestation. Epidemiological setting (e.g., endemic areas, seasons) and an accurate diagnostic approach (i.e., clinical history, physical examination and laboratory tests) are necessary to confirm TBDs. Further, control and prevention of TBDs is warranted. Research in the fields of ticks microbiome and vaccination (i.e., wildlife and humans) are ahead to control vector transmission and bacterial infection. This review offers a comprehensive update on TBDs and their relationship with autoimmunity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pathogens vectored by the tick, Dermacentor reticulatus, in endemic regions and zones of expansion in Poland.

PubMed

Mierzejewska, Ewa J; Pawełczyk, Agnieszka; Radkowski, Marek; Welc-Falęciak, Renata; Bajer, Anna

2015-09-24

Dermacentor reticulatus plays an important role in the maintenance of pathogens of medical and veterinary importance in the environment. Currently two isolated populations of D. reticulatus are present in Poland--Western and Eastern. The range of the Eastern population covers endemic areas in eastern Poland but this population is expanding westwards creating an expansion zone in the centre of the country. The expansion zone in western Poland is occupied by the recently discovered Western population, spreading eastwards. Questing adult ticks (n = 2585) were collected in 2012-2014 in endemic regions of north-eastern (Warmińsko-Mazurskie Voivodeship) and central Poland (Masovian Voivodeship) and in the expansion zones in central and western Poland, in the region between the Vistula River and the western border of the country. Amplification of Babesia, Rickettsia spp. and Borrelia burgdorferi sensu lato DNAs was performed using specific starters. RNA of the TBE virus was detected using RT-PCR and representative PCR products were sequenced and compared with sequences deposited in GenBank. Of the total 2585 examined ticks, 1197 (46.3 %) were infected with at least one pathogen. Overall prevalence of pathogens was 4.18 % (108/2585) for Babesia spp., 44.10 % (1140/2585) for Rickettsia spp., 0.09 % (1/1107) for Borrelia afzelii and 7.6 % (7/92) for TBEV. Sequence analysis of DNA showed 99.86 % similarity to R. raoulti and 99.81 % to B. canis. One male from north-eastern Poland was infected with B. microti. Prevalence of R. raoulti was highest in the Western population (52.03 %) and lowest in the Eastern population in north-eastern Poland (34.18 %). Babesia canis was not detected in 592 ticks collected in the Western population, while in the Eastern population overall prevalence was 5.42 %. There were significant differences in the prevalence of B. canis between tick samples from northern (0.68 %), central (1.18 %) and southern (14.8 %) areas of the expansion zone in central Poland. Our study found significant differences between the range and prevalence of vectored pathogens in D. reticulatus from the endemic areas and newly inhabited expansion zones. The differences were likely associated with the different time of settlement or 'source' of ticks populations, the Eastern and the Western one.

Influence of the biotope on the tick infestation of cattle and on the tick-borne pathogen repertoire of cattle ticks in Ethiopia.

PubMed

Hornok, Sándor; Abichu, Getachew; Meli, Marina L; Tánczos, Balázs; Sulyok, Kinga M; Gyuranecz, Miklós; Gönczi, Enikő; Farkas, Róbert; Hofmann-Lehmann, Regina

2014-01-01

The majority of vector-borne infections occur in the tropics, including Africa, but molecular eco-epidemiological studies are seldom reported from these regions. In particular, most previously published data on ticks in Ethiopia focus on species distribution, and only a few molecular studies on the occurrence of tick-borne pathogens or on ecological factors influencing these. The present study was undertaken to evaluate, if ticks collected from cattle in different Ethiopian biotopes harbour (had access to) different pathogens. In South-Western Ethiopia 1032 hard ticks were removed from cattle grazing in three kinds of tick biotopes. DNA was individually extracted from one specimen of both sexes of each tick species per cattle. These samples were molecularly analysed for the presence of tick-borne pathogens. Amblyomma variegatum was significantly more abundant on mid highland, than on moist highland. Rhipicephalus decoloratus was absent from savannah lowland, where virtually only A. cohaerens was found. In the ticks Coxiella burnetii had the highest prevalence on savannah lowland. PCR positivity to Theileria spp. did not appear to depend on the biotope, but some genotypes were unique to certain tick species. Significantly more A. variegatum specimens were rickettsia-positive, than those of other tick species. The presence of rickettsiae (R. africae) appeared to be associated with mid highland in case of A. variegatum and A. cohaerens. The low level of haemoplasma positivity seemed to be equally distributed among the tick species, but was restricted to one biotope type. The tick biotope, in which cattle are grazed, will influence not only the tick burden of these hosts, but also the spectrum of pathogens in their ticks. Thus, the presence of pathogens with alternative (non-tick-borne) transmission routes, with transstadial or with transovarial transmission by ticks appeared to be associated with the biotope type, with the tick species, or both, respectively.

Virulence of recurrent infestations with Borrelia-infected ticks in a Borrelia-amplifying bird

NASA Astrophysics Data System (ADS)

Heylen, Dieter J. A.; Müller, Wendt; Vermeulen, Anke; Sprong, Hein; Matthysen, Erik

2015-11-01

Lyme disease cases caused by Borrelia burgdorferi s.l. bacteria is increasing steadily in Europe, in part due to the expansion of the vector, Ixodes ricinus. Wild reservoir hosts are typically recurrently infested. Understanding the impact of these cumulative parasite exposures on the host’s health is, therefore, central to predict the distribution of tick populations and their pathogens. Here, we have experimentally investigated the symptoms of disease caused by recurrent infestations in a common songbird (Parus major). Birds were exposed three times in succession to ticks collected in a Borrelia endemic area. Health and immune measures were analyzed in order to investigate changes in response to tick infestation and Borrelia infection rate. Nitric oxide levels increased with the Borrelia infection rate, but this effect was increasingly counteracted by mounting tick infestation rates. Tick infestations equally reduced haematocrit during each cycle. But birds overcompensated in their response to tick feeding, having higher haematocrit values during tick-free periods depending on the number of ticks they had been previously exposed to. Body condition showed a similar overshooting response in function of the severity of the Borrelia infection. The observed overcompensation increases the bird’s energetic needs, which may result in an increase in transmission events.

A multiplex serologic platform for diagnosis of tick-borne diseases.

PubMed

Tokarz, Rafal; Mishra, Nischay; Tagliafierro, Teresa; Sameroff, Stephen; Caciula, Adrian; Chauhan, Lokendrasingh; Patel, Jigar; Sullivan, Eric; Gucwa, Azad; Fallon, Brian; Golightly, Marc; Molins, Claudia; Schriefer, Martin; Marques, Adriana; Briese, Thomas; Lipkin, W Ian

2018-02-16

Tick-borne diseases are the most common vector-borne diseases in the United States, with serology being the primary method of diagnosis. We developed the first multiplex, array-based assay for serodiagnosis of tick-borne diseases called the TBD-Serochip. The TBD-Serochip was designed to discriminate antibody responses to 8 major tick-borne pathogens present in the United States, including Anaplasma phagocytophilum, Babesia microti, Borrelia burgdorferi, Borrelia miyamotoi, Ehrlichia chaffeensis, Rickettsia rickettsii, Heartland virus and Powassan virus. Each assay contains approximately 170,000 12-mer linear peptides that tile along the protein sequence of the major antigens from each agent with 11 amino acid overlap. This permits accurate identification of a wide range of specific immunodominant IgG and IgM epitopes that can then be used to enhance diagnostic accuracy and integrate differential diagnosis into a single assay. To test the performance of the TBD-Serochip, we examined sera from patients with confirmed Lyme disease, babesiosis, anaplasmosis, and Powassan virus disease. We identified a wide range of specific discriminatory epitopes that facilitated accurate diagnosis of each disease. We also identified previously undiagnosed infections. Our results indicate that the TBD-Serochip is a promising tool for a differential diagnosis not available with currently employed serologic assays for TBDs.

The tick plasma lectin, Dorin M, is a fibrinogen-related molecule.

PubMed

Rego, Ryan O M; Kovár, Vojtĕch; Kopácek, Petr; Weise, Christoph; Man, Petr; Sauman, Ivo; Grubhoffer, Libor

2006-04-01

A lectin, named Dorin M, previously isolated and characterized from the hemolymph plasma of the soft tick, Ornithodoros moubata, was cloned and sequenced. The immunofluorescence using confocal microscopy revealed that Dorin M is produced in the tick hemocytes. A tryptic cleavage of Dorin M was performed and the resulting peptide fragments were sequenced by Edman degradation and/or mass spectrometry. Two of three internal peptide sequences displayed a significant similarity to the family of fibrinogen-related molecules. Degenerate primers were designed and used for PCR with hemocyte cDNA as a template. The sequence of the whole Dorin M cDNA was completed by the method of RACE. The tissue-specific expression investigated by RT-PCR revealed that Dorin M, in addition to hemocytes, is significantly expressed in salivary glands. The derived amino-acid sequence clearly shows that Dorin M has a fibrinogen-like domain, and exhibited the most significant similarity with tachylectins 5A and 5B from a horseshoe crab, Tachypleus tridentatus. In addition, other protein and binding characteristics suggest that Dorin M is closely related to tachylectins-5. Since these lectins have been reported to function as non-self recognizing molecules, we believe that Dorin M may play a similar role in an innate immunity of the tick and, possibly, also in pathogen transmission by this vector.

A Dual Luciferase Reporter System for B. burgdorferi Measures Transcriptional Activity during Tick-Pathogen Interactions

PubMed Central

Adams, Philip P.; Flores Avile, Carlos; Jewett, Mollie W.

2017-01-01

Knowledge of the transcriptional responses of vector-borne pathogens at the vector-pathogen interface is critical for understanding disease transmission. Borrelia (Borreliella) burgdorferi, the causative agent of Lyme disease in the United States, is transmitted by the bite of infected Ixodes sp. ticks. It is known that B. burgdorferi has altered patterns of gene expression during tick acquisition, persistence and transmission. Recently, we and others have discovered in vitro expression of RNAs found internal, overlapping, and antisense to annotated open reading frames in the B. burgdorferi genome. However, there is a lack of molecular genetic tools for B. burgdorferi for quantitative, strand-specific, comparative analysis of these transcripts in distinct environments such as the arthropod vector. To address this need, we have developed a dual luciferase reporter system to quantify B. burgdorferi promoter activities in a strand-specific manner. We demonstrate that constitutive expression of a B. burgdorferi codon-optimized Renilla reniformis luciferase gene (rlucBb) allows normalization of the activity of a promoter of interest when fused to the B. burgdorferi codon-optimized Photinus pyralis luciferase gene (flucBb) on the same plasmid. Using the well characterized, differentially regulated, promoters for flagellin (flaBp), outer surface protein A (ospAp) and outer surface protein C (ospCp), we document the efficacy of the dual luciferase system for quantitation of promoter activities during in vitro growth and in infected ticks. Cumulatively, the dual luciferase method outlined herein is the first dual reporter system for B. burgdorferi, providing a novel and highly versatile approach for strand-specific molecular genetic analyses. PMID:28620587

A Dual Luciferase Reporter System for B. burgdorferi Measures Transcriptional Activity during Tick-Pathogen Interactions.

PubMed

Adams, Philip P; Flores Avile, Carlos; Jewett, Mollie W

2017-01-01

Knowledge of the transcriptional responses of vector-borne pathogens at the vector-pathogen interface is critical for understanding disease transmission. Borrelia ( Borreliella ) burgdorferi , the causative agent of Lyme disease in the United States, is transmitted by the bite of infected Ixodes sp . ticks. It is known that B. burgdorferi has altered patterns of gene expression during tick acquisition, persistence and transmission. Recently, we and others have discovered in vitro expression of RNAs found internal, overlapping, and antisense to annotated open reading frames in the B. burgdorferi genome. However, there is a lack of molecular genetic tools for B. burgdorferi for quantitative, strand-specific, comparative analysis of these transcripts in distinct environments such as the arthropod vector. To address this need, we have developed a dual luciferase reporter system to quantify B. burgdorferi promoter activities in a strand-specific manner. We demonstrate that constitutive expression of a B. burgdorferi codon-optimized Renilla reniformis luciferase gene ( rluc Bb ) allows normalization of the activity of a promoter of interest when fused to the B. burgdorferi codon-optimized Photinus pyralis luciferase gene ( fluc Bb ) on the same plasmid. Using the well characterized, differentially regulated, promoters for flagellin ( flaBp ), outer surface protein A ( ospAp ) and outer surface protein C ( ospCp ), we document the efficacy of the dual luciferase system for quantitation of promoter activities during in vitro growth and in infected ticks. Cumulatively, the dual luciferase method outlined herein is the first dual reporter system for B. burgdorferi , providing a novel and highly versatile approach for strand-specific molecular genetic analyses.

A quantitative synthesis of the role of birds in carrying ticks and tick-borne pathogens in North America.

PubMed

Loss, Scott R; Noden, Bruce H; Hamer, Gabriel L; Hamer, Sarah A

2016-12-01

Birds play a central role in the ecology of tick-borne pathogens. They expand tick populations and pathogens across vast distances and serve as reservoirs that maintain and amplify transmission locally. Research into the role of birds for supporting ticks and tick-borne pathogens has largely been descriptive and focused in small areas. To expand inference beyond these studies, we conducted a quantitative review at the scale of North America to identify avian life history correlates of tick infestation and pathogen prevalence, calculate species-level indices of importance for carrying ticks, and identify research gaps limiting understanding of tick-borne pathogen transmission. Across studies, 78 of 162 bird species harbored ticks, yielding an infestation prevalence of 1981 of 38,929 birds (5.1 %). Avian foraging and migratory strategies interacted to influence infestation. Ground-foraging species, especially non-migratory ground foragers, were disproportionately likely to have high prevalence and intensity of tick infestation. Studies largely focused on Borrelia burgdorferi, the agent of Lyme disease, and non-migratory ground foragers were especially likely to carry B. burgdorferi-infected ticks, a finding that highlights the potential importance of resident birds in local pathogen transmission. Based on infestation indices, all "super-carrier" bird species were passerines. Vast interior areas of North America, many bird and tick species, and most tick-borne pathogens, remain understudied, and research is needed to address these gaps. More studies are needed that quantify tick host preferences, host competence, and spatiotemporal variation in pathogen prevalence and vector and host abundance. This information is crucial for predicting pathogen transmission dynamics under future global change.

Why are there so few Rickettsia conorii conorii-infected Rhipicephalus sanguineus ticks in the wild?

PubMed

Socolovschi, Cristina; Gaudart, Jean; Bitam, Idir; Huynh, Thi Phong; Raoult, Didier; Parola, Philippe

2012-01-01

Rickettsia conorii conorii is the etiological agent of Mediterranean spotted fever, which is transmitted by the brown dog tick, Rhipicephalus sanguineus. The relationship between the Rickettsia and its tick vector are still poorly understood one century after the first description of this disease. An entomological survey was organized in Algeria to collect ticks from the houses of patients with spotted fever signs. Colonies of R. conorii conorii-infected and non-infected ticks were established under laboratory conditions. Gimenez staining and electron microscopy on the ovaries of infected ticks indicated heavy rickettsial infection. The transovarial transmission of R. conorii conorii in naturally infected Rh. sanguineus ticks was 100% at eleven generations, and the filial infection rate was up to 99% according to molecular analyses. No differences in life cycle duration were observed between infected and non-infected ticks held at 25°C, but the average weight of engorged females and eggs was significantly lower in infected ticks than in non-infected ticks. The eggs, larvae and unfed nymphs of infected and non-infected ticks could not tolerate low (4°C) or high (37°C) temperatures or long starvation periods. R. conorii conorii-infected engorged nymphs that were exposed to a low or high temperature for one month experienced higher mortality when they were transferred to 25°C than non-infected ticks after similar exposure. High mortality was observed in infected adults that were maintained for one month at a low or high temperature after tick-feeding on rabbits. These preliminary results suggest that infected quiescent ticks may not survive the winter and may help explain the low prevalence of infected Rh. sanguineus in nature. Further investigations on the influence of extrinsic factors on diapaused R. conorii-infected and non-infected ticks are required.

Induction of humoral immune response to multiple recombinant Rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission.

PubMed

Olds, Cassandra L; Mwaura, Stephen; Odongo, David O; Scoles, Glen A; Bishop, Richard; Daubenberger, Claudia

2016-09-02

Rhipicephalus appendiculatus is the primary vector of Theileria parva, the etiological agent of East Coast fever (ECF), a devastating disease of cattle in sub-Saharan Africa. We hypothesized that a vaccine targeting tick proteins that are involved in attachment and feeding might affect feeding success and possibly reduce tick-borne transmission of T. parva. Here we report the evaluation of a multivalent vaccine cocktail of tick antigens for their ability to reduce R. appendiculatus feeding success and possibly reduce tick-transmission of T. parva in a natural host-tick-parasite challenge model. Cattle were inoculated with a multivalent antigen cocktail containing recombinant tick protective antigen subolesin as well as two additional R. appendiculatus saliva antigens: the cement protein TRP64, and three different histamine binding proteins. The cocktail also contained the T. parva sporozoite antigen p67C. The effect of vaccination on the feeding success of nymphal and adult R. appendiculatus ticks was evaluated together with the effect on transmission of T. parva using a tick challenge model. To our knowledge, this is the first evaluation of the anti-tick effects of these antigens in the natural host-tick-parasite combination. In spite of evidence of strong immune responses to all of the antigens in the cocktail, vaccination with this combination of tick and parasite antigens did not appear to effect tick feeding success or reduce transmission of T. parva. The results of this study highlight the importance of early evaluation of anti-tick vaccine candidates in biologically relevant challenge systems using the natural tick-host-parasite combination.

Survey of selected tick-borne diseases in dogs in Finland.

PubMed

Pérez Vera, Cristina; Kapiainen, Suvi; Junnikkala, Sami; Aaltonen, Kirsi; Spillmann, Thomas; Vapalahti, Olli

2014-06-23

Due to climate changes during the last decades, ticks have progressively spread into higher latitudes in northern Europe. Although some tick borne diseases are known to be endemic in Finland, to date there is limited information with regard to the prevalence of these infections in companion animals. We determined the antibody and DNA prevalence of the following organisms in randomly selected client-owned and clinically healthy hunting dogs living in Finland: Ehrlichia canis (Ec), Anaplasma phagocytophilum (Ap), Borrelia burgdorferi (Bb) and Bartonella. Anti-Ap, -Bb and -Ec antibodies were determined in 340 Finnish pet dogs and 50 healthy hunting dogs using the 4DX Snap®Test (IDEXX Laboratories). In addition, PCRs for the detection of Ap and Bartonella DNA were performed. Univariate and multivariate logistic regression analyses were used to identify risk factors associated with seropositivity to a vector borne agent. The overall seroprevalence was highest for Ap (5.3%), followed by Bb (2.9%), and Ec (0.3%). Seropositivities to Ap and Bb were significantly higher in the Åland Islands (p <0.001), with prevalence of Ap and Bb antibodies of 45 and 20%, respectively. In healthy hunting dogs, seropositivity rates of 4% (2/50) and 2% (1/50) were recorded for Ap and Bb, respectively. One client-owned dog and one hunting dog, both healthy, were infected with Ap as determined by PCR, while being seronegative. For Bartonella spp., none of the dogs tested was positive by PCR. This study represents the first data of seroprevalence to tick borne diseases in the Finnish dog population. Our results indicate that dogs in Finland are exposed to vector borne diseases, with Ap being the most seroprevalent of the diseases tested, followed by Bb. Almost 50% of dogs living in Åland Islands were Ap seropositive. This finding suggests the possibility of a high incidence of Ap infection in humans in this region. Knowing the distribution of seroprevalence in dogs may help predict the pattern of a tick borne disease and may aid in diagnostic and prevention efforts.

Molecular detection of zoonotic tick-borne pathogens from ticks collected from ruminants in four South African provinces.

PubMed

Mtshali, Khethiwe; Khumalo, Zth; Nakao, Ryo; Grab, Dennis J; Sugimoto, Chihiro; Thekisoe, Omm

2016-01-01

Ticks carry and transmit a remarkable array of pathogens including bacteria, protozoa and viruses, which may be of veterinary and/or of medical significance. With little to no information regarding the presence of tick-borne zoonotic pathogens or their known vectors in southern Africa, the aim of our study was to screen for Anaplasma phagocytophilum, Borrelia burgdorferi, Coxiella burnetii, Rickettsia species and Ehrlichia ruminantium in ticks collected and identified from ruminants in the Eastern Cape, Free State, KwaZulu-Natal and Mpumalanga Provinces of South Africa. The most abundant tick species identified in this study were Rhipicephalus evertsi evertsi (40%), Rhipicephalus species (35%), Amblyomma hebraeum (10%) and Rhipicephalus decoloratus (14%). A total of 1634 ticks were collected. DNA was extracted, and samples were subjected to PCR amplification and sequencing. The overall infection rates of ticks with the target pathogens in the four Provinces were as follows: A. phagocytophilum, 7%; C. burnetii, 7%; E. ruminantium, 28%; and Rickettsia spp., 27%. The presence of B. burgdorferi could not be confirmed. The findings of this study show that zoonotic pathogens are present in ticks in the studied South African provinces. This information will aid in the epidemiology of tick-borne zoonotic diseases in the country as well as in raising awareness about such diseases in the veterinary, medical and tourism sectors, as they may be the most affected.

Reverse transcription PCR-based detection of Crimean-Congo hemorrhagic fever virus isolated from ticks of domestic ruminants in Kurdistan province of Iran.

PubMed

Fakoorziba, Mohammad Reza; Golmohammadi, Parvaneh; Moradzadeh, Rahmatollah; Moemenbellah-Fard, Mohammad Djaefar; Azizi, Kourosh; Davari, Behrooz; Alipour, Hamzeh; Ahmadnia, Sara; Chinikar, Sadegh

2012-09-01

Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal viral vector-borne zoonosis which has a mortality rate of up to 30% without treatment in humans. CCHF virus is transmitted to humans by ticks, predominantly from the Hyalomma genus. Following the report of two confirmed and one suspected death due to CCHF virus in Kurdistan province of Iran in 2007, this study was undertaken to determine the fauna of hard ticks on domestic ruminants (cattle, sheep, and goats) and their possible infection with CCHF virus using reverse transcription PCR technique. This is the first detection of CCHF virus in ticks from the Kurdistan province of Iran. Overall, 414 ixodid ticks were collected from two districts in this province. They represented four genera from which 10 separate species were identified. The Hyalomma genus was the most abundant tick genus (70%). It was the only genus shown to be infected with the CCHF virus using RT-PCR technique. The number of ticks positive for CCHF virus was 5 out of 90 (5.6%) adult ticks. The three remaining genera (Haemaphysalis, Rhipicephalus, and Dermacentor) were all negative following molecular survey. Four of the five virally-infected ticks were from cattle mainly in the Sanandaj district. We concluded that CCHF virus is present in the Hyalomma ticks on domestic ruminants (cattle) in Kurdistan province of Iran.

Past and future perspectives on mathematical models of tick-borne pathogens.

PubMed

Norman, R A; Worton, A J; Gilbert, L

2016-06-01

Ticks are vectors of pathogens which are important both with respect to human health and economically. They have a complex life cycle requiring several blood meals throughout their life. These blood meals take place on different individual hosts and potentially on different host species. Their life cycle is also dependent on environmental conditions such as the temperature and habitat type. Mathematical models have been used for the more than 30 years to help us understand how tick dynamics are dependent on these environmental factors and host availability. In this paper, we review models of tick dynamics and summarize the main results. This summary is split into two parts, one which looks at tick dynamics and one which looks at tick-borne pathogens. In general, the models of tick dynamics are used to determine when the peak in tick densities is likely to occur in the year and how that changes with environmental conditions. The models of tick-borne pathogens focus more on the conditions under which the pathogen can persist and how host population densities might be manipulated to control these pathogens. In the final section of the paper, we identify gaps in the current knowledge and future modelling approaches. These include spatial models linked to environmental information and Geographic Information System maps, and development of new modelling techniques which model tick densities per host more explicitly.

Molecular Ecological Insights into Neotropical Bird–Tick Interactions

PubMed Central

Esser, Helen J.; Loaiza, Jose R.; Herre, Edward Allen; Aguilar, Celestino; Quintero, Diomedes; Alvarez, Eric; Bermingham, Eldredge

2016-01-01

In the tropics, ticks parasitize many classes of vertebrate hosts. However, because many tropical tick species are only identifiable in the adult stage, and these adults usually parasitize mammals, most attention on the ecology of tick-host interactions has focused on mammalian hosts. In contrast, immature Neotropical ticks are often found on wild birds, yet difficulties in identifying immatures hinder studies of birds’ role in tropical tick ecology and tick-borne disease transmission. In Panama, we found immature ticks on 227 out of 3,498 individually–sampled birds representing 93 host species (24% of the bird species sampled, and 13% of the Panamanian land bird fauna). Tick parasitism rates did not vary with rainfall or temperature, but did vary significantly with several host ecological traits. Likewise, Neotropical–Nearctic migratory birds were significantly less likely to be infested than resident species. Using a molecular library developed from morphologically–identified adult ticks specifically for this study, we identified eleven tick species parasitizing birds, indicating that a substantial portion of the Panamanian avian species pool is parasitized by a diversity of tick species. Tick species that most commonly parasitized birds had the widest diversity of avian hosts, suggesting that immature tick species are opportunistic bird parasites. Although certain avian ecological traits are positively associated with parasitism, we found no evidence that individual tick species show specificity to particular avian host ecological traits. Finally, our data suggest that the four principal vectors of Rocky Mountain Spotted Fever in the Neotropics rarely, if ever, parasitize Panamanian birds. However, other tick species that harbor newly–discovered rickettsial parasites of unknown pathogenicity are frequently found on these birds. Given our discovery of broad interaction between Panamanian tick and avian biodiversity, future work on tick ecology and the dynamics of emerging tropical tick-borne pathogens should explicitly consider wild bird as hosts. PMID:27203693

Variation in the Microbiota of Ixodes Ticks with Regard to Geography, Species, and Sex.

PubMed

Van Treuren, Will; Ponnusamy, Loganathan; Brinkerhoff, R Jory; Gonzalez, Antonio; Parobek, Christian M; Juliano, Jonathan J; Andreadis, Theodore G; Falco, Richard C; Ziegler, Lorenza Beati; Hathaway, Nicholas; Keeler, Corinna; Emch, Michael; Bailey, Jeffrey A; Roe, R Michael; Apperson, Charles S; Knight, Rob; Meshnick, Steven R

2015-09-01

Ixodes scapularis is the principal vector of Lyme disease on the East Coast and in the upper Midwest regions of the United States, yet the tick is also present in the Southeast, where Lyme disease is absent or rare. A closely related species, I. affinis, also carries the pathogen in the South but does not seem to transmit it to humans. In order to better understand the geographic diversity of the tick, we analyzed the microbiota of 104 adult I. scapularis and 13 adult I. affinis ticks captured in 19 locations in South Carolina, North Carolina, Virginia, Connecticut, and New York. Initially, ticks from 4 sites were analyzed by 454 pyrosequencing. Subsequently, ticks from these sites plus 15 others were analyzed by sequencing with an Illumina MiSeq machine. By both analyses, the microbiomes of female ticks were significantly less diverse than those of male ticks. The dissimilarity between tick microbiomes increased with distance between sites, and the state in which a tick was collected could be inferred from its microbiota. The genus Rickettsia was prominent in all locations. Borrelia was also present in most locations and was present at especially high levels in one site in western Virginia. In contrast, members of the family Enterobacteriaceae were very common in North Carolina I. scapularis ticks but uncommon in I. scapularis ticks from other sites and in North Carolina I. affinis ticks. These data suggest substantial variations in the Ixodes microbiota in association with geography, species, and sex. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Synanthropic Mammals as Potential Hosts of Tick-Borne Pathogens in Panama

PubMed Central

Bermúdez, Sergio E.; Gottdenker, Nicole; Krishnvajhala, Aparna; Fox, Amy; Wilder, Hannah K.; González, Kadir; Smith, Diorene; López, Marielena; Perea, Milixa; Rigg, Chystrie; Montilla, Santiago; Calzada, José E.; Saldaña, Azael; Caballero, Carlos M.

2017-01-01

Synanthropic wild mammals can be important hosts for many vector-borne zoonotic pathogens. The aim of this study was determine the exposure of synanthropic mammals to two types of tick-borne pathogens in Panama, spotted fever group Rickettsia (SFGR) and Borrelia relapsing fever (RF) spirochetes. One hundred and thirty-one wild mammals were evaluated, including two gray foxes, two crab-eating foxes (from zoos), four coyotes, 62 opossum and 63 spiny rats captured close to rural towns. To evaluate exposure to SFGR, serum samples from the animals were tested by indirect immunofluorescence assay (IFA) using Rickettsia rickettsii and Candidatus Rickettsia amblyommii antigen. Immunoblotting was performed using Borrelia turicatae protein lysates and rGlpQ, to assess infection caused by RF spirochetes. One coyote (25%) and 27 (43%) opossums showed seroreactivity to SFGR. Of these opossums, 11 were seroreactive to C. R. amblyommii. Serological reactivity was not detected to B. turicatae in mammal samples. These findings may reflect a potential role of both mammals in the ecology of tick-borne pathogens in Panama. PMID:28060928

Dynamics of Exposure to Rickettsia parkeri in Cattle in the Paraná River Delta, Argentina.

PubMed

Monje, L D; Costa, F B; Colombo, V C; Labruna, M B; Antoniazzi, L R; Gamietea, I; Nava, S; Beldomenico, P M

2016-05-01

Several cases of human rickettsiosis caused by Rickettsia parkeri were recently documented in the Paraná River delta of Argentina, where the tick vector is Amblyomma triste Koch. As cattle suffer recurrent A. triste infestations, they are at risk of becoming infected with R. parkeri Herein we investigated the dynamics of R. parkeri and its A. triste vector in a herd of beef cattle. Cattle were followed for 18 mo and samples were analyzed for the presence of antibodies against four Rickettsia species (R. parkeri, Rickettsia bellii, Rickettsia amblyommii, and Rickettsia felis) and also for the presence of rickettsial DNA. Additionally, cattle were examined for attached ticks and questing adult ticks were collected. All ticks were analyzed for the presence of rickettsial DNA. No evidence of rickettsemia was found in any cow, but the high R. parkeri infection rate documented in A. triste both questing in the study area (13.9%) and feeding on cattle (19.8%) and the identification of antibodies against R. parkeri antigen in 90% of cattle are evidence that infection is taking place. Altogether, our data suggest that A. triste ticks are capable of naturally exposing cattle to R. parkeri However, the progress of R. parkeri infection and its impact on bovine health and production remain to be established. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Experiences in Tick Control by Acaricide in the Traditional Cattle Sector in Zambia and Burkina Faso: Possible Environmental and Public Health Implications

PubMed Central

De Meneghi, Daniele; Stachurski, Frédéric; Adakal, Hassane

2016-01-01

Livestock, especially cattle, play a paramount role in agriculture production systems, particularly in poor countries throughout the world. Ticks and tick-borne diseases (TBDs) have an important impact on livestock and agriculture production in sub-Saharan Africa. The authors review the most common methods used for the control of ticks and TBDs. Special emphasis is given to the direct application of acaricides to the host animals. The possible environmental and public health adverse effects (i.e., risks for the workers, residues in the environment and in food products of animal origin) are mentioned. The authors present two case studies, describing different field experiences in controlling ticks in two African countries. In Zambia (Southern Africa), a strategic dipping regime was used to control Rhipicephalus appendiculatus ticks, vectors of theileriosis, a deadly disease affecting cattle in the traditional livestock sector in Southern Province. The dipping regime adopted allowed to reduce the tick challenge and cattle mortally rate and, at the same time, to employ less acaricide as compared to the intensive dipping used so far, without disrupting the building-up of enzootic stability. In Burkina Faso (West Africa), where dipping was never used for tick control, an acaricide footbath was employed as an alternative method to the traditional technique used locally (portable manual sprayers). This was developed from field observations on the invasion/attachment process of the Amblyomma variegatum ticks – vector of cowdriosis – on the animal hosts, leading to a control method aimed to kill ticks temporarily attached to the interdigital areas before their permanent attachment to the predilection sites. This innovative method has been overall accepted by the local farmers. It has the advantage of greatly reducing costs of treatments and has a minimal environmental impact, making footbath a sustainable and replicable method, adoptable also in other West African countries. Although the two methods described, developed in very different contexts, are not comparable – if public health and environmental implications are taken into account, if a balance among efficacy of the control method(s), cost-effectiveness and sustainability is reached – a way forward for the implementation of a One Health strategy can be set. PMID:27882313

Integrated Strategy for Sustainable Cattle Fever Tick Eradication in USA is Required to Mitigate the Impact of Global Change

PubMed Central

Pérez de León, Adalberto A.; Teel, Pete D.; Auclair, Allan N.; Messenger, Matthew T.; Guerrero, Felix D.; Schuster, Greta; Miller, Robert J.

2012-01-01

The ticks Rhipicephalus (Boophilus) annulatus and R. (B.) microplus, commonly known as cattle and southern cattle tick, respectively, impede the development and sustainability of livestock industries throughout tropical and other world regions. They affect animal productivity and wellbeing directly through their obligate blood-feeding habit and indirectly by serving as vectors of the infectious agents causing bovine babesiosis and anaplasmosis. The monumental scientific discovery of certain arthropod species as vectors of infectious agents is associated with the history of research on bovine babesiosis and R. annulatus. Together, R. microplus and R. annulatus are referred to as cattle fever ticks (CFT). Bovine babesiosis became a regulated foreign animal disease in the United States of America (U.S.) through efforts of the Cattle Fever Tick Eradication Program (CFTEP) established in 1906. The U.S. was declared free of CFT in 1943, with the exception of a permanent quarantine zone in south Texas along the border with Mexico. This achievement contributed greatly to the development and productivity of animal agriculture in the U.S. The permanent quarantine zone buffers CFT incursions from Mexico where both ticks and babesiosis are endemic. Until recently, the elimination of CFT outbreaks relied solely on the use of coumaphos, an organophosphate acaricide, in dipping vats or as a spray to treat livestock, or the vacation of pastures. However, ecological, societal, and economical changes are shifting the paradigm of systematically treating livestock to eradicate CFT. Keeping the U.S. CFT-free is a critical animal health issue affecting the economic stability of livestock and wildlife enterprises. Here, we describe vulnerabilities associated with global change forces challenging the CFTEP. The concept of integrated CFT eradication is discussed in reference to global change. PMID:22712018

9 CFR 72.2 - Splenetic or tick fever in cattle in Texas, the Virgin Islands of the United States and vectors...

Code of Federal Regulations, 2013 CFR

2013-01-01

... Islands, the Commonwealth of Puerto Rico and the Island of Guam: Restrictions on movement of cattle. 72.2... States and vectors of said disease in the Northern Mariana Islands, the Commonwealth of Puerto Rico and... are vectors of said disease exist in the Northern Mariana Islands, the Commonwealth of Puerto Rico...

9 CFR 72.2 - Splenetic or tick fever in cattle in Texas, the Virgin Islands of the United States and vectors...

Code of Federal Regulations, 2010 CFR

2010-01-01

... Islands, the Commonwealth of Puerto Rico and the Island of Guam: Restrictions on movement of cattle. 72.2... States and vectors of said disease in the Northern Mariana Islands, the Commonwealth of Puerto Rico and... are vectors of said disease exist in the Northern Mariana Islands, the Commonwealth of Puerto Rico...

9 CFR 72.2 - Splenetic or tick fever in cattle in Texas, the Virgin Islands of the United States and vectors...

Code of Federal Regulations, 2011 CFR

2011-01-01

... Islands, the Commonwealth of Puerto Rico and the Island of Guam: Restrictions on movement of cattle. 72.2... States and vectors of said disease in the Northern Mariana Islands, the Commonwealth of Puerto Rico and... are vectors of said disease exist in the Northern Mariana Islands, the Commonwealth of Puerto Rico...

9 CFR 72.2 - Splenetic or tick fever in cattle in Texas, the Virgin Islands of the United States and vectors...

Code of Federal Regulations, 2012 CFR

2012-01-01

... Islands, the Commonwealth of Puerto Rico and the Island of Guam: Restrictions on movement of cattle. 72.2... States and vectors of said disease in the Northern Mariana Islands, the Commonwealth of Puerto Rico and... are vectors of said disease exist in the Northern Mariana Islands, the Commonwealth of Puerto Rico...

Identification of Tick Species Collected from Wild Boars and Habitats of Wild Boars and Domestic Pigs in the Republic of Korea.

PubMed

Chae, Jeong-Byoung; Kang, Jun-Gu; Kim, Heung-Chul; Chong, Sung-Tae; Lee, In-Yong; Shin, Nam-Shik; Chae, Joon-Seok

2017-04-01

Tick is one of the most important arthropods in the transmission of vector-borne diseases. In this study, we investigated the abundance and species of ticks associated with swine and their habitats to assess the risk of spread of tick-borne diseases in host species, such as wild boars. Ticks were collected from 24 grazing or traditionally reared domestic pig farms and 8 habitats of wild boars in 8 provinces and 1 city in the Republic of Korea, by using the dragging and flagging methods. Ticks were also collected directly from 49 wild boars by using fine forceps. A total of 9,846 hard ticks were collected, including 4,977 Haemaphysalis longicornis , 4,313 Haemaphysalis flava , 508 Ixodes nipponensis , 1 Ixodes turdus , and 47 Amblyomma testudinarium . A total of 240 hard ticks were collected from 49 wild boars, including 109 H. flava , 84 H. longicornis , and 47 A. testudinarium . A total of 578 hard ticks were collected from areas around domestic pig farms. Only 2 hard tick species, 546 H. longicornis and 32 H. flava , were collected from these areas. A total of 9,028 hard ticks were collected from wild boars of 8 habitats, including 4,347 H. longicornis , 4,172 H. flava , 508 I. nipponensis , and 1 I. turdus . A. testudinarium was collected only from wild boars, and I. nipponensis and I. turdus were collected only from the habitats of wild boars.

Prevalence of tick-borne pathogens in Ixodes ricinus and Dermacentor reticulatus ticks from different geographical locations in Belarus.

PubMed

Reye, Anna L; Stegniy, Valentina; Mishaeva, Nina P; Velhin, Sviataslau; Hübschen, Judith M; Ignatyev, George; Muller, Claude P

2013-01-01

Worldwide, ticks are important vectors of human and animal pathogens. Besides Lyme Borreliosis, a variety of other bacterial and protozoal tick-borne infections are of medical interest in Europe. In this study, 553 questing and feeding Ixodes ricinus (n = 327) and Dermacentor reticulatus ticks (n = 226) were analysed by PCR for Borrelia, Rickettsia, Anaplasma, Coxiella, Francisella and Babesia species. Overall, the pathogen prevalence in ticks was 30.6% for I. ricinus and 45.6% for D. reticulatus. The majority of infections were caused by members of the spotted-fever group rickettsiae (24.4%), 9.4% of ticks were positive for Borrelia burgdorferi sensu lato, with Borrelia afzelii being the most frequently detected species (40.4%). Pathogens with low prevalence rates in ticks were Anaplasma phagocytophilum (2.2%), Coxiella burnetii (0.9%), Francisella tularensis subspecies (0.7%), Bartonella henselae (0.7%), Babesia microti (0.5%) and Babesia venatorum (0.4%). On a regional level, hotspots of pathogens were identified for A. phagocytophilum (12.5-17.2%), F. tularensis ssp. (5.5%) and C. burnetii (9.1%), suggesting established zoonotic cycles of these pathogens at least at these sites. Our survey revealed a high burden of tick-borne pathogens in questing and feeding I. ricinus and D. reticulatus ticks collected in different regions in Belarus, indicating a potential risk for humans and animals. Identified hotspots of infected ticks should be included in future surveillance studies, especially when F. tularensis ssp. and C. burnetii are involved.

Ticks (Ixodidae) on birds migrating from Europe and Asia to Africa, 1959-61*

PubMed Central

Hoogstraal, Harry; Kaiser, Makram N.; Traylor, Melvin A.; Guindy, Ezzat; Gaber, Sobhy

1963-01-01

The need for imaginative thinking and research in the epidemiology of diseases transmitted by arthropods is made manifest by new views of the longevity and host ranges of arthropod-borne viruses, as well as by other biological and medical phenomena. Among these is the intercontinental transport of ticks by migrating birds. During the fall migration periods of 1959, 1960 and 1961, 32 086 birds (comprising 72 forms) were examined for ticks in Egypt while en route from Asia and eastern Europe to tropical Africa. Of these, 40 forms, represented by 31 434 birds, were tick-infested. The bird hosts, numbering 1040 (3.31% of the tick-infested bird forms examined), bore 1761 ticks, or 1.69 ticks per host. Common ticks taken were Hyalomma m. marginatum, Haemaphysalis punctata, and Ixodes ricinus. Ixodes frontalis and Hyalomma aegyptium were less common and Haemaphysalis sulcata, H. otophila, and H. pavlovskyi were rare. The common tick species are known to be reservoirs and vectors of pathogens causing a number of human and animal diseases in Europe and Asia. Several of the bird hosts have also been incriminated as reservoirs in their summer ranges. Over 20 strains of pathogenic viruses were isolated from these birds and their ticks in Egypt in the 1961 fall migration period. The most difficult problems in investigations such as this in many parts of the world are taxonomic ones: the correct identification of bird hosts, of immature stages of ticks and of viruses. PMID:13961632

Tick-borne pathogens in ticks collected from birds in Taiwan.

PubMed

Kuo, Chi-Chien; Lin, Yi-Fu; Yao, Cheng-Te; Shih, Han-Chun; Chung, Lo-Hsuan; Liao, Hsien-Chun; Hsu, Yu-Cheng; Wang, Hsi-Chieh

2017-11-25

A variety of human diseases transmitted by arthropod vectors, including ticks, are emerging around the globe. Birds are known to be hosts of ticks and can disperse exotic ticks and tick-borne pathogens. In Taiwan, previous studies have focused predominantly on mammals, leaving the role of birds in the maintenance of ticks and dissemination of tick-borne pathogens undetermined. Ticks were collected opportunistically when birds were studied from 1995 to 2013. Furthermore, to improve knowledge on the prevalence and mean load of tick infestation on birds in Taiwan, ticks were thoroughly searched for when birds were mist-netted at seven sites between September 2014 and April 2016 in eastern Taiwan. Ticks were identified based on both morphological and molecular information and were screened for potential tick-borne pathogens, including the genera Anaplasma, Babesia, Borrelia, Ehrlichia and Rickettsia. Finally, a list of hard tick species collected from birds in Taiwan was compiled based on past work and the current study. Nineteen ticks (all larvae) were recovered from four of the 3096 unique mist-netted bird individuals, yielding a mean load of 0.006 ticks/individual and an overall prevalence of 0.13%. A total of 139 ticks from birds, comprising 48 larvae, 35 nymphs, 55 adults and one individual of unknown life stage, were collected from 1995 to 2016, and 11 species of four genera were identified, including three newly recorded species (Haemaphysalis wellingtoni, Ixodes columnae and Ixodes turdus). A total of eight tick-borne pathogens were detected, with five species (Borrelia turdi, Anaplasma sp. clone BJ01, Ehrlichia sp. BL157-9, Rickettsia helvetica and Rickettsia monacensis) not previously isolated in Taiwan. Overall, 16 tick species of five genera have been recorded feeding on birds, including nine species first discovered in this study. Our study demonstrates the paucity of information on ticks of birds and emphasizes the need for more research on ticks of birds in Taiwan and Southeast Asia. Moreover, some newly recorded ticks and tick-borne pathogens were found only on migratory birds, demonstrating the necessity of further surveillance on these highly mobile species.

Are ticks venomous animals?

PubMed Central

2014-01-01

Introduction As an ecological adaptation venoms have evolved independently in several species of Metazoa. As haematophagous arthropods ticks are mainly considered as ectoparasites due to directly feeding on the skin of animal hosts. Ticks are of major importance since they serve as vectors for several diseases affecting humans and livestock animals. Ticks are rarely considered as venomous animals despite that tick saliva contains several protein families present in venomous taxa and that many Ixodida genera can induce paralysis and other types of toxicoses. Tick saliva was previously proposed as a special kind of venom since tick venom is used for blood feeding that counteracts host defense mechanisms. As a result, the present study provides evidence to reconsider the venomous properties of tick saliva. Results Based on our extensive literature mining and in silico research, we demonstrate that ticks share several similarities with other venomous taxa. Many tick salivary protein families and their previously described functions are homologous to proteins found in scorpion, spider, snake, platypus and bee venoms. This infers that there is a structural and functional convergence between several molecular components in tick saliva and the venoms from other recognized venomous taxa. We also highlight the fact that the immune response against tick saliva and venoms (from recognized venomous taxa) are both dominated by an allergic immunity background. Furthermore, by comparing the major molecular components of human saliva, as an example of a non-venomous animal, with that of ticks we find evidence that ticks resemble more venomous than non-venomous animals. Finally, we introduce our considerations regarding the evolution of venoms in Arachnida. Conclusions Taking into account the composition of tick saliva, the venomous functions that ticks have while interacting with their hosts, and the distinguishable differences between human (non-venomous) and tick salivary proteins, we consider that ticks should be referred to as venomous ectoparasites. PMID:25006341

The Blacklegged Tick, Ixodes scapularis: An Increasing Public Health Concern.

PubMed

Eisen, Rebecca J; Eisen, Lars

2018-04-01

In the United States, the blacklegged tick, Ixodes scapularis, is a vector of seven human pathogens, including those causing Lyme disease, anaplasmosis, babesiosis, Borrelia miyamotoi disease, Powassan virus disease, and ehrlichiosis associated with Ehrlichia muris eauclarensis. In addition to an accelerated rate of discovery of I. scapularis-borne pathogens over the past two decades, the geographic range of the tick, and incidence and range of I. scapularis-borne disease cases, have increased. Despite knowledge of when and where humans are most at risk of exposure to infected ticks, control of I. scapularis-borne diseases remains a challenge. Human vaccines are not available, and we lack solid evidence for other prevention and control methods to reduce human disease. The way forward is discussed. Published by Elsevier Ltd.

Occurrence of tick-borne haemoparasites in cattle in the Mungwi District, Northern Province, Zambia.

PubMed

Tembo, Stephen; Collins, Nicola E; Sibeko-Matjila, Kgomotso P; Troskie, Milana; Vorster, Ilse; Byaruhanga, Charles; Oosthuizen, Marinda C

2018-03-01

Little is known about the occurrence of haemoparasites in cattle in communal grazing areas of Mungwi District of Northern Province, Zambia. Clinical signs and post mortem lesions are pathognomonic of mixed tick-borne infections especially babesiosis, anaplasmosis and East Coast fever. The main objective of this study was to screen selected communal herds of cattle for tick-borne haemoparasites, and identify the tick vectors associated with the high cattle mortalities due to suspected tick-borne diseases in the local breeds of cattle grazing along the banks of the Chambeshi River in Mungwi District, Northern Province, Zambia. A total of 299 cattle blood samples were collected from July to September 2010 from Kapamba (n = 50), Chifulo (n = 102), Chisanga (n = 38), Kowa (n = 95) and Mungwi central (n = 14) in the Mungwi District. A total of 5288 ticks were also collected from the sampled cattle from April to July 2011. DNA was extracted from the cattle blood and the hypervariable region of the parasite small subunit rRNA gene was amplified and subjected to the reverse line blot (RLB) hybridization assay. The results of the RLB assay revealed the presence of tick-borne haemoparasites in 259 (86.6%) cattle blood samples occurring either as single (11.0%) or mixed (75.6%) infections. The most prevalent species present were the benign Theileria mutans (54.5%) and T. velifera (51.5%). Anaplasma marginale (25.7%), Babesia bovis (7.7%) and B. bigemina (3.3%) DNA were also detected in the samples. Only one sample (from Kapamba) tested positive for the presence of T. parva. This was an unexpected finding; also because the tick vector, Rhipicephalus appendiculatus, was identified on animals from Kowa (14.0%), Chisanga (8.5%), Chifulo (6.0%) and Kapamba (1.4%). One sample (from Kapamba) tested positive for the presence of Ehrlichia ruminantium even though Amblyomma variegatum ticks were identified from 52.9% of the sampled animals from all study areas. There was significant positive association between T. mutans and T. velifera (p < 0.001) infections, and between A. marginale and B. bovis (p = 0.005). The presence of R. microplus tick vectors on cattle was significantly associated with B. bovis (odds ratio, OR = 28.4, p < 0.001) and A. marginale (OR = 42.0, p < 0.001) infections, while A. variegatum presence was significantly associated with T. mutans (OR = 213.0, p < 0.001) and T. velifera (OR = 459.0, p < 0.001) infections. Rhipicephalus decoloratus was significantly associated with B. bigemina (OR = 21.6, p = 0.004) and A. marginale (OR = 28.5, p < 0.001). Multivariable analysis showed a significant association between location and tick-borne pathogen status for A. marginale (p < 0.001), T. mutans (p = 0.004), T. velifera (p = 0.003) and T. taurotragi (p = 0.005). The results of our study suggest that the cause of cattle mortalities in Mungwi during the winter outbreaks is mainly due to A. marginale, B. bovis and B. bigemina infections. This was confirmed by the clinical manifestation of the disease in the affected cattle and the tick species identified on the animals. The relatively low prevalence of T. parva, B. bigemina, B. bovis and E. ruminantium could indicate the existence of endemic instability with a pool of susceptible cattle and the occurrence of disease outbreaks. Copyright © 2018 Elsevier GmbH. All rights reserved.

Molecular detection of severe fever with thrombocytopenia syndrome and tick-borne encephalitis viruses in ixodid ticks collected from vegetation, Republic of Korea, 2014.

PubMed

Yun, Seok-Min; Lee, Ye-Ji; Choi, WooYoung; Kim, Heung-Chul; Chong, Sung-Tae; Chang, Kyu-Sik; Coburn, Jordan M; Klein, Terry A; Lee, Won-Ja

2016-07-01

Ticks play an important role in transmission of arboviruses responsible for emerging infectious diseases, and have a significant impact on human, veterinary, and wildlife health. In the Republic of Korea (ROK), little is known about information regarding the presence of tick-borne viruses and their vectors. A total of 21,158 ticks belonging to 3 genera and 6 species collected at 6 provinces and 4 metropolitan areas in the ROK from March to October 2014 were assayed for selected tick-borne pathogens. Haemaphysalis longicornis (n=17,570) was the most numerously collected, followed by Haemaphysalis flava (n=3317), Ixodes nipponensis (n=249), Amblyomma testudinarium (n=11), Haemaphysalis phasiana (n=8), and Ixodes turdus (n=3). Ticks were pooled (adults 1-5, nymphs 1-30, and larvae 1-50) and tested by one-step reverse transcription polymerase chain reaction (RT-PCR) or nested RT-PCR for the detection of severe fever with thrombocytopenia virus (SFTSV), tick-borne encephalitis virus (TBEV), Powassan virus (POWV), Omsk hemorrhagic fever virus (OHFV), and Langat virus (LGTV). The overall maximum likelihood estimation (MLE) [estimated numbers of viral RNA positive ticks/1000 ticks] for SFTSV and TBEV was 0.95 and 0.43, respectively, while, all pools were negative for POWV, OHFV, and LGTV. The purpose of this study was to determine the prevalence of SFTSV, TBEV, POWV, OHFV, and LGTV in ixodid ticks collected from vegetation in the ROK to aid our understanding of the epidemiology of tick-borne viral diseases. Results from this study emphasize the need for continuous tick-based arbovirus surveillance to monitor the emergence of tick-borne diseases in the ROK. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

Immune Cell Targets of Infection at the Tick-Skin Interface during Powassan Virus Transmission.

PubMed

Hermance, Meghan E; Santos, Rodrigo I; Kelly, Brent C; Valbuena, Gustavo; Thangamani, Saravanan

2016-01-01

Powassan virus (POWV) is a tick-borne flavivirus that can result in a severe neuroinvasive disease with 50% of survivors displaying long-term neurological sequelae. Human POWV cases have been documented in Canada, the United States, and Russia. Although the number of reported POWV human cases has increased in the past fifteen years, POWV remains one of the less studied human pathogenic flaviviruses. Ixodes ticks are the vectors for POWV, and the virus is transmitted to a host's skin very early during the tick feeding process. Central to the successful transmission of a tick-borne pathogen are complex interactions between the host immune response and early tick-mediated immunomodulation, all of which initially occur at the skin interface. In our prior work, we examined the cutaneous immune gene expression during the early stages of POWV-infected Ixodes scapularis feeding. The present study serves to further investigate the skin interface by identifying early cell targets of infection at the POWV-infected tick feeding site. An in vivo infection model consisting of POWV-infected ticks feeding on mice for short durations was used in this study. Skin biopsies from the tick feeding sites were harvested at various early time points, enabling us to examine the skin histopathology and detect POWV viral antigen in immune cells present at the tick feeding site. The histopathology from the present study demonstrates that neutrophil and mononuclear cell infiltrates are recruited earlier to the feeding site of a POWV-infected tick versus an uninfected tick. This is the first report demonstrating that macrophages and fibroblasts contain POWV antigens, which suggests that they are early cellular targets of infection at the tick feeding site. These data provide key insights towards defining the complex interactions between the host immune response and early tick-mediated immunomodulation.

Multi-Scale Clustering of Lyme Disease Risk at the Expanding Leading Edge of the Range of Ixodes scapularis in Canada

PubMed Central

Lindsay, Leslie Robbin; Ludwig, Antoinette; Ogden, Nicholas H.; Thivierge, Karine; Leighton, Patrick A.

2018-01-01

Since its detection in Canada in the early 1990s, Ixodes scapularis, the primary tick vector of Lyme disease in eastern North America, has continued to expand northward. Estimates of the tick’s broad-scale distribution are useful for tracking the extent of the Lyme disease risk zone; however, tick distribution may vary widely within this zone. Here, we investigated I. scapularis nymph distribution at three spatial scales across the Lyme disease emergence zone in southern Quebec, Canada. We collected ticks and compared the nymph densities among different woodlands and different plots and transects within the same woodland. Hot spot analysis highlighted significant nymph clustering at each spatial scale. In regression models, nymph abundance was associated with litter depth, humidity, and elevation, which contribute to a suitable habitat for ticks, but also with the distance from the trail and the type of trail, which could be linked to host distribution and human disturbance. Accounting for this heterogeneous nymph distribution at a fine spatial scale could help improve Lyme disease management strategies but also help people to understand the risk variation around them and to adopt appropriate behaviors, such as staying on the trail in infested parks to limit their exposure to the vector and associated pathogens. PMID:29584627

The lyme disease pathogen has no effect on the survival of its rodent reservoir host.

PubMed

Voordouw, Maarten J; Lachish, Shelly; Dolan, Marc C

2015-01-01

Zoonotic pathogens that cause devastating morbidity and mortality in humans may be relatively harmless in their natural reservoir hosts. The tick-borne bacterium Borrelia burgdorferi causes Lyme disease in humans but few studies have investigated whether this pathogen reduces the fitness of its reservoir hosts under natural conditions. We analyzed four years of capture-mark-recapture (CMR) data on a population of white-footed mice, Peromyscus leucopus, to test whether B. burgdorferi and its tick vector affect the survival of this important reservoir host. We used a multi-state CMR approach to model mouse survival and mouse infection rates as a function of a variety of ecologically relevant explanatory factors. We found no effect of B. burgdorferi infection or tick burden on the survival of P. leucopus. Our estimates of the probability of infection varied by an order of magnitude (0.051 to 0.535) and were consistent with our understanding of Lyme disease in the Northeastern United States. B. burgdorferi establishes a chronic avirulent infection in their rodent reservoir hosts because this pathogen depends on rodent mobility to achieve transmission to its sedentary tick vector. The estimates of B. burgdorferi infection risk will facilitate future theoretical studies on the epidemiology of Lyme disease.

Molecular epidemiology of the emerging zoonosis agent Anaplasma phagocytophilum (Foggie, 1949) in dogs and ixodid ticks in Brazil.

PubMed

Santos, Huarrisson A; Thomé, Sandra M G; Baldani, Cristiane D; Silva, Claudia B; Peixoto, Maristela P; Pires, Marcus S; Vitari, Gabriela L V; Costa, Renata L; Santos, Tiago M; Angelo, Isabele C; Santos, Leandro A; Faccini, João L H; Massard, Carlos L

2013-12-11

Anaplasma phagocytophilum is an emerging pathogen of humans, dogs and other animals, and it is transmitted by ixodid ticks. The objective of the current study was a) detect A. phagocytophilum in dogs and ixodid ticks using real-time Polymerase Chain Reaction (qPCR); and b) Determine important variables associated to host, environment and potential tick vectors that are related to the presence of A. phagocytophilum in dogs domiciled in Rio de Janeiro, Brazil. We tested blood samples from 398 dogs and samples from 235 ticks, including 194 Rhipicephalus sanguineus sensu lato, 15 Amblyomma cajennense, 8 Amblyomma ovale and 18 pools of Amblyomma sp. nymphs. A semi-structured questionnaire was applied by interviewing each dog owner. Deoxyribonucleic acid obtained from ticks and dog buffy coat samples were amplified by qPCR (msp2 gene). The sequencing of 16S rRNA and groESL heat shock operon genes and a phylogenetic analysis was performed. The multiple logistic regression model was created as a function of testing positive dogs for A. phagocytophilum. Among the 398 blood samples from dogs, 6.03% were positive for A. phagocytophilum. Anaplasma phagocytophilum was detected in one A. cajennense female tick and in five R. sanguineus sensu lato ticks (four males and one female). The partial sequences of the 16S rRNA, and groESL genes obtained were highly similar to strains of A. phagocytophilum isolated from wild birds from Brazil and human pathogenic strains. The tick species collected in positive dogs were R. sanguineus sensu lato and A. cajennense, with A.cajennense being predominant. Tick infestation history (OR = 2.86, CI = 1.98-14.87), dog size (OR = 2.41, IC: 1.51-12.67), the access to forest areas (OR = 3:51, CI: 1.52-16.32), hygiene conditions of the environment in which the dogs lived (OR = 4.35, CI: 1.86-18.63) and Amblyomma sp. infestation (OR = 6.12; CI: 2.11-28.15) were associated with A. phagocytophilum infection in dogs. This is the first report of A. phagocytophilum in ixodid ticks from Brazil. The detection of A. phagocitophylum in A. cajennense, an aggressive feeder on a wide variety of hosts, including humans, is considered a public health concern.

Crimean-Congo hemorrhagic fever virus in livestock ticks and animal handler seroprevalence at an abattoir in Ghana.

PubMed

Akuffo, R; Brandful, J A M; Zayed, A; Adjei, A; Watany, N; Fahmy, N T; Hughes, R; Doman, B; Voegborlo, S V; Aziati, D; Pratt, D; Awuni, J A; Adams, N; Dueger, E

2016-07-08

Crimean-Congo Haemorrhagic Fever Virus (CCHFV) is a zoonotic virus transmitted by Ixodid ticks and causes Crimean-Congo hemorrhagic fever (CCHF) disease in humans with up to 50 % mortality rate. Freshly slaughtered livestock at the Kumasi abattoir in the Ashanti Region of Ghana were examined for the presence of ticks once a month over a 6-month period from May to November 2011. The ticks were grouped into pools by species, sex, and animal source. CCHFV was detected in the ticks using reverse transcription PCR. Blood samples were collected from enrolled abattoir workers at initiation, and from those who reported fever in a preceding 30-day period during monthly visits 2-5 months after initiation. Six months after initiation, all participants who provided baseline samples were invited to provide blood samples. Serology was performed using enzyme linked immunosorbent assay (ELISA). Demographic and epidemiological data was also obtained from enrolled participants using a structured questionnaire. Of 428 freshly slaughtered animals comprising 130 sheep, 149 cattle, and 149 goats examined, 144 ticks belonging to the genera Ambylomma, Hyalomma and Boophilus were identified from 57 (13.3 %): 52 (34.9 %), 4 (3.1 %) and 1 (0.7 %) cattle, sheep and goat respectively. Of 97 tick pools tested, 5 pools comprising 1 pool of Hyalomma excavatum and 4 pools of Ambylomma variegatum, collected from cattle, were positive for CCHFV. Of 188 human serum samples collected from 108 abattoir workers, 7 (3.7 %) samples from 6 persons were anti-CCHF IgG positive with one of them also being CCHF IgM positive. The seroprevalence of CCHFV identified in this study was 5.7 %. This study detected human exposure to CCHF virus in slaughterhouse workers and also identified the CCHF virus in proven vectors (ticks) of Crimean Congo hemorrhagic fever in Ghana. The CCHFV was detected only in ticks collected from cattle, one of the livestock known to play a role in the amplification of the CCHF virus.

Extremely Low Genomic Diversity of Rickettsia japonica Distributed in Japan.

PubMed

Akter, Arzuba; Ooka, Tadasuke; Gotoh, Yasuhiro; Yamamoto, Seigo; Fujita, Hiromi; Terasoma, Fumio; Kida, Kouji; Taira, Masakatsu; Nakadouzono, Fumiko; Gokuden, Mutsuyo; Hirano, Manabu; Miyashiro, Mamoru; Inari, Kouichi; Shimazu, Yukie; Tabara, Kenji; Toyoda, Atsushi; Yoshimura, Dai; Itoh, Takehiko; Kitano, Tomokazu; Sato, Mitsuhiko P; Katsura, Keisuke; Mondal, Shakhinur Islam; Ogura, Yoshitoshi; Ando, Shuji; Hayashi, Tetsuya

2017-01-01

Rickettsiae are obligate intracellular bacteria that have small genomes as a result of reductive evolution. Many Rickettsia species of the spotted fever group (SFG) cause tick-borne diseases known as "spotted fevers". The life cycle of SFG rickettsiae is closely associated with that of the tick, which is generally thought to act as a bacterial vector and reservoir that maintains the bacterium through transstadial and transovarial transmission. Each SFG member is thought to have adapted to a specific tick species, thus restricting the bacterial distribution to a relatively limited geographic region. These unique features of SFG rickettsiae allow investigation of how the genomes of such biologically and ecologically specialized bacteria evolve after genome reduction and the types of population structures that are generated. Here, we performed a nationwide, high-resolution phylogenetic analysis of Rickettsia japonica, an etiological agent of Japanese spotted fever that is distributed in Japan and Korea. The comparison of complete or nearly complete sequences obtained from 31 R. japonica strains isolated from various sources in Japan over the past 30 years demonstrated an extremely low level of genomic diversity. In particular, only 34 single nucleotide polymorphisms were identified among the 27 strains of the major lineage containing all clinical isolates and tick isolates from the three tick species. Our data provide novel insights into the biology and genome evolution of R. japonica, including the possibilities of recent clonal expansion and a long generation time in nature due to the long dormant phase associated with tick life cycles. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Golden jackals (Canis aureus) as hosts for ticks and tick-borne pathogens in Serbia.

PubMed

Sukara, Ratko; Chochlakis, Dimosthenis; Ćirović, Duško; Penezić, Aleksandra; Mihaljica, Darko; Ćakić, Sanja; Valčić, Miroslav; Tselentis, Yannis; Psaroulaki, Anna; Tomanović, Snežana

2018-04-10

The golden jackal (Canis aureus) is a medium-sized canid species native to Europe. This species is characterized by rapid large-scale expansion. A similar trend is also observed in Serbia, where the species is now distributed in more than a half of the territory. Although jackals prefer habitats in human-dominated landscapes, these animals have not been studied well enough from an eco-epidemiological point of view, and little is known about their potential for carrying zoonotic pathogens. In a study conducted during a three-year period (01/2010-02/2013), a total of 216 hunted or road-killed golden jackals were collected from 10 localities in Serbia. Ticks, when present, were removed, and after necropsy, spleen samples were collected from each animal. All tick and spleen samples were tested for the DNA of bacterial and protozoan tick-borne pathogens (Borrelia species, Bartonella species, Rickettsia species, Anaplasma species, Coxiella burnetii, Francisella species and Babesia species) by multiplex real-time PCR, conventional PCR and sequencing analyses. The DNA of Babesia canis was detected in nine out of 216 (4.2%) spleen samples, and two samples (0.9%) tested positive for Anaplasma phagocytophilum. In 118 ticks collected from jackals, the DNA of two Babesia species (Ba. canis and Ba. microti), three Borrelia species (Bo. garinii, Bo. valaisiana, and Bo. lusitaniae) and A. marginale was detected. From the aspect of public health surveillance, the potential role of the golden jackal in the maintenance of vector-borne zoonotic pathogens in Serbia must be considered, and further eco-epidemiological studies should be performed to determine the precise role of this animal species in zoonotic disease transmission cycles. Copyright © 2018 Elsevier GmbH. All rights reserved.

Prevalence and Distribution of Human and Tick Infections with the Ehrlichia muris-Like Agent and Anaplasma phagocytophilum in Wisconsin, 2009-2015.

PubMed

Murphy, Darby S; Lee, Xia; Larson, Scott R; Johnson, Diep K Hoang; Loo, Theoren; Paskewitz, Susan M

2017-04-01

Ehrlichiosis and anaplasmosis are important emerging tickborne zoonoses that affect both humans and animals. Knowledge of the geographic distribution and prevalence of Ehrlichia spp. and Anaplasma phagocytophilum in Wisconsin is important information as a baseline for future comparisons. Reported human cases between 2009 and 2015 were identified using the Wisconsin Electronic Disease Surveillance System (WEDSS) and mapped by county of residence. Vector surveillance was established using ticks collected from animals by partners, including veterinary medical clinics, domestic animal shelters, and wildlife rehabilitation centers from 40 Wisconsin counties. A total of 1835 Ixodes scapularis tick specimens (larvae, nymphs, and adults) were collected from 18 different domestic and wildlife species from July 2011 to November 2015. An additional 1136 nymphs were collected by drag sampling at 23 locations in 19 counties in 2015. A real-time PCR assay that detects and distinguishes several Ehrlichia species, including a pathogenic Ehrlichia muris-like agent (EMLA), and A. phagocytophilum was performed on adult and nymphal ticks. A total of 757 I. scapularis ticks (predominately adults) were tested from animal collections, with 67 (8.9%) individuals positive for A. phagocytophilum and 22 (2.9%) positive for EMLA DNA. Of the 1150 questing nymphs, 62 (5.4%) were positive for A. phagocytophilum and 10 (0.9%) were positive for EMLA DNA. Specimens of I. scapularis that were positive for A. phagocytophilum were found in 27 of the 33 counties surveyed. Specimens that were positive for EMLA were less common and were found in nine counties. This study provides the first statewide survey of I. scapularis ticks for these pathogens and indicates that the risk of human exposure is widely distributed.

Transovarial persistence of Babesia ovata DNA in a hard tick, Haemaphysalis longicornis, in a semi-artificial mouse skin membrane feeding system.

PubMed

Umemiya-Shirafuji, Rika; Hatta, Takeshi; Okubo, Kazuhiro; Sato, Moeko; Maeda, Hiroki; Kume, Aiko; Yokoyama, Naoaki; Igarashi, Ikuo; Tsuji, Naotoshi; Fujisaki, Kozo; Inoue, Noboru; Suzuki, Hiroshi

2017-12-20

Bovine piroplasmosis, a tick-borne protozoan disease, is a major concern for the cattle industry worldwide due to its negative effects on livestock productivity. Toward the development of novel therapeutic and vaccine approaches, tick-parasite experimental models have been established to clarify the development of parasites in the ticks and the transmission of the parasites by ticks. A novel tick-Babesia experimental infection model recently revealed the time course of Babesia ovata migration in its vector Haemaphysalis longicornis, which is a dominant tick species in Japan. However, there has been no research on the transovarial persistence of B. ovata DNA using this experimental infection model. Here we assessed the presence of B. ovata DNA in eggs derived from parthenogenetic H. longicornis female ticks that had engorged after semi-artificial mouse skin membrane feeding of B. ovata-infected bovine red blood cells. The oviposition period of the engorged female ticks was 21-24 days in the semi-artificial feeding. Total egg weight measured daily reached a peak by day 3 in all female ticks. Nested PCR revealed that 3 of 10 female ticks laid B. ovata DNA-positive eggs after the semi-artificial feeding. In addition, B. ovata DNA was detected at the peak of egg weight during oviposition, indicating that B. ovata exist in the eggs laid a few days after the onset of oviposition in the tick. These findings will contribute to the establishment of B. ovata-infected H. longicornis colonies under laboratory conditions.

Ticks collected from humans, domestic animals, and wildlife in Yucatan, Mexico.

PubMed

Rodríguez-Vivas, R I; Apanaskevich, D A; Ojeda-Chi, M M; Trinidad-Martínez, I; Reyes-Novelo, E; Esteve-Gassent, M D; Pérez de León, A A

2016-01-15

Domestic animals and wildlife play important roles as reservoirs of zoonotic pathogens that are transmitted to humans by ticks. Besides their role as vectors of several classes of microorganisms of veterinary and public health relevance, ticks also burden human and animal populations through their obligate blood-feeding habit. It is estimated that in Mexico there are around 100 tick species belonging to the Ixodidae and Argasidae families. Information is lacking on tick species that affect humans, domestic animals, and wildlife through their life cycle. This study was conducted to bridge that knowledge gap by inventorying tick species that infest humans, domestic animals and wildlife in the State of Yucatan, Mexico. Amblyomma ticks were observed as euryxenous vertebrate parasites because they were found parasitizing 17 animal species and human. Amblyomma mixtum was the most eryxenous species found in 11 different animal species and humans. Both A. mixtum and A. parvum were found parasitizing humans. Ixodes near affinis was the second most abundant species parasitizing six animal species (dogs, cats, horses, white-nosed coati, white-tail deer and black vulture) and was found widely across the State of Yucatan. Ixodid tick populations may increase in the State of Yucatan with time due to animal production intensification, an increasing wildlife population near rural communities because of natural habitat reduction and fragmentation. The diversity of ticks across host taxa documented here highlights the relevance of ecological information to understand tick-host dynamics. This knowledge is critical to inform public health and veterinary programs for the sustainable control of ticks and tick-borne diseases. Copyright © 2015. Published by Elsevier B.V.

Infections and Coinfections of Questing Ixodes ricinus Ticks by Emerging Zoonotic Pathogens in Western Switzerland

PubMed Central

Lommano, Elena; Bertaiola, Luce; Dupasquier, Christèle

2012-01-01

In Europe, Ixodes ricinus is the vector of many pathogens of medical and veterinary relevance, among them Borrelia burgdorferi sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like Rickettsia spp., Babesia spp., “Candidatus Neoehrlichia mikurensis,” and Anaplasma phagocytophilum in questing ticks. In this study, questing nymph and adult I. ricinus ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of B. burgdorferi sensu lato, Rickettsia spp., Babesia spp., “Candidatus Neoehrlichia mikurensis,” and A. phagocytophilum. B. burgdorferi sensu lato, Rickettsia spp., and “Candidatus Neoehrlichia mikurensis” were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively. Babesia- and A. phagocytophilum-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like Borrelia spielmanii, Borrelia lusitaniae, and Rickettsia monacensis, were identified. Infections with more than one pathogenic species, involving mostly Borrelia spp. and Rickettsia helvetica, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in I. ricinus in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite. PMID:22522688

Babesia canis and other tick-borne infections in dogs in Central Poland.

PubMed

Welc-Faleciak, Renata; Rodo, Anna; Siński, Edward; Bajer, Anna

2009-12-23

Vector-borne infections constitute increasing health problem in dogs worldwide, including sled dogs, dramatically decreasing the fitness of working dogs and even leading to death. In the period 2006-2008 eighty-two blood samples were collected from eight sled dog kennels in Central Poland. The prevalence of four vector-borne infections (Babesia canis, Bartonella sp., Anaplasma/Ehrlichia and Borrelia burgdorferi) was estimated in 82 sled dogs using PCR and nested PCR for diagnosis and the same methods were used to identify the vector-borne pathogens in 26 dogs presenting at veterinary clinics with symptoms of vector-borne diseases. None of four studied vector-borne pathogens was detected in samples originating from veterinary clinics. Among the remaining 82 dogs B. canis infections were confirmed in three dogs undergoing treatment for babesiosis. The DNA of tick-borne pathogens was also found among 22 (27.8%) of the 79 apparently healthy dogs, including 20 cases of B. canis infection (25.3%), one case of B. burgdorferi s.l. infection and one case of Anaplasma phagocytophilum infection. No evidence of Bartonella spp. and Ehrlichia canis infections were found in this set of samples. Sequencing of a Babesia fragment of 18S rDNA amplified from acute (n=5) and asymptomatic (n=5) cases revealed that all isolates were identical to the Babesia canis canis sequence, originally isolated from Dermacentor reticulatus ticks in Poland. A range of factors was shown to affect the distribution of babesiosis in sled dogs. The data are also discussed in respect to the health risk factors generated by asymptomatic B. canis infections and the efficiency of chemoprophylaxis measures taken by sled dog owners.

Vector competence of the blacklegged tick, Ixodes scapularis, for the recently recognized Lyme borreliosis spirochete Candidatus Borrelia mayonii.

PubMed

Dolan, Marc C; Hojgaard, Andrias; Hoxmeier, J Charles; Replogle, Adam J; Respicio-Kingry, Laurel B; Sexton, Christopher; Williams, Martin A; Pritt, Bobbi S; Schriefer, Martin E; Eisen, Lars

2016-07-01

A novel species within the Borrelia burgdorferi sensu lato complex, provisionally named Borrelia mayonii, was recently found to be associated with Lyme borreliosis in the Upper Midwest of the United States. Moreover, B. mayonii was detected from host-seeking Ixodes scapularis, the primary vector of B. burgdorferi sensu stricto in the eastern United States. We therefore conducted a study to confirm the experimental vector competence of I. scapularis for B. mayonii (strain MN14-1420), using colony ticks originating from adults collected in Connecticut and CD-1 white mice. Larvae fed on mice 10 weeks after needle-inoculation with B. mayonii acquired spirochetes and maintained infection through the nymphal stage at an average rate of 12.9%. In a transmission experiment, 40% of naïve mice exposed to a single infected nymph developed viable infections, as compared with 87% of mice fed upon by 2-3 infected nymphs. Transmission of B. mayonii by one or more feeding infected nymphs was uncommon up to 48h after attachment (one of six mice developed viable infection) but occurred frequently when nymphs were allowed to remain attached for 72-96h or feed to completion (11 of 16 mice developed viable infection). Mice infected via tick bite maintained viable infection with B. mayonii, as determined by ear biopsy culture, for at least 28 weeks. Our results demonstrate that I. scapularis is capable of serving as a vector of B. mayonii. This finding, together with data showing that field-collected I. scapularis are infected with B. mayonii, indicate that I. scapularis likely is a primary vector to humans of this recently recognized Lyme borreliosis spirochete. Published by Elsevier GmbH.

Ecology and Disease Transmission Potential in the Colombian Amazon Basin.

DTIC Science & Technology

BRAZIL, *DISEASE VECTORS, *PARASITIC DISEASES, COLOMBIA, ECOLOGY, COLOMBIA, COLOMBIA, INFECTIOUS DISEASES, DIPTERA, HUMANS, EQUINES , BOVINES, REPTILES, TICKS, ANNELIDA, NEMATODA, PLATYHELMINTHES, FILARIAE.

Effects of wildlife and cattle on tick abundance in central Kenya.

PubMed

Keesing, Felicia; Allan, Brian F; Young, Truman P; Ostfeld, Richard S

2013-09-01

In African savannas, large mammals, both wild and domestic, support an abundant and diverse population of tick ectoparasites. Because of the density of ticks and the many pathogens that they vector, cattle in East Africa are often treated with acaricides. While acaricides are known to be effective at reducing tick burdens on cattle, their effects on the overall abundance and community composition of ticks in savanna ecosystems are less well understood. It is also not known how well tick populations can be maintained in the absence of large mammals. We evaluated the effects of wildlife and of acaricide-treated cattle on host-seeking tick populations in a long-term, exclusion experiment in central Kenya. Over seven years, we sampled larval, nymphal, and adult ticks monthly on replicated treatment plots that controlled for the presence of cattle and for the presence of two guilds of large wild mammals: megaherbivores (giraffes and elephants) and all other large wild herbivores (> 15 kg). Two species of ticks were found in this habitat; across all surveys, 93% were Rhipicephalus pulchellus and 7% were R. praetextatus. The presence of acaricide-treated cattle dramatically reduced the abundance of host-seeking nymphal and adult ticks but did not affect the abundance of host-seeking larval ticks. The abundance of larval ticks was determined by the presence of large wild mammals, which appear to import gravid female ticks into the experimental plots. On plots with no large mammals, either wild or domestic, larval and nymphal ticks were rare. Adult R. pulchellus were most abundant in plots that allowed wildlife but excluded cattle. Adult R. praetextatus were relatively abundant in plots without any large mammals. These differences suggest that these ticks utilize different members of the host community. The reduction in ticks that results from the presence of acaricide-treated cattle has potential health benefits for humans and wildlife, but these benefits must be weighed against potential costs, including reduced availability of food for birds such as oxpeckers that feed on ticks.

Detection of a novel Rickettsia sp. in soft ticks (Acari: Argasidae) in Algeria.

PubMed

Lafri, Ismail; Leulmi, Hamza; Baziz-Neffah, Fadhila; Lalout, Reda; Mohamed, Chergui; Mohamed, Karakallah; Parola, Philippe; Bitam, Idir

2015-01-01

Argasid ticks are vectors of viral and bacterial agents that can infect humans and animals. In Africa, relapsing fever borreliae are neglected arthropod-borne pathogens that cause mild to deadly septicemia and miscarriage. It would be incredibly beneficial to be able to simultaneous detect and identify other pathogens transmitted by Argasid ticks. From 2012 to 2014, we conducted field surveys in 4 distinct areas of Algeria. We investigated the occurrence of soft ticks in rodent burrows and yellow-legged gull (Larus michahellis) nests in 10 study sites and collected 154 soft ticks. Molecular identification revealed the occurrence of two different soft tick genera and five species, including Carios capensis in yellow-legged gull nests and Ornithodoros occidentalis, Ornithodoros rupestris, Ornithodoros sonrai, Ornithodoros erraticus in rodent burrows. Rickettsial DNA was detected in 41/154, corresponding to a global detection rate of 26.6%. Sequences of the citrate synthase (gltA) gene suggest that this agent is a novel spotted fever group Rickettsia. For the first time in Algeria, we characterize a novel Rickettsia species by molecular means in soft ticks. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Predicted outcomes of vaccinating wildlife to reduce human risk of Lyme disease.

PubMed

Tsao, Kimberly; Fish, Durland; Galvani, Alison P

2012-07-01

Vaccination efforts for Lyme disease prevention in humans have focused on wildlife reservoirs to target the causative agent, Borrelia burgdorferi, for elimination in vector ticks. Multiple host species are involved in the transmission and maintenance of the bacterium, but not all host species can be vaccinated effectively. To evaluate vaccinating a subset of hosts in the context of host-tick interactions, we constructed and evaluated a dynamic model of B. burgdorferi transmission in mice. Our analyses indicate that on average, a mouse-targeted vaccine is expected to proportionally reduce infection prevalence among ticks by 56%. However, relative to mouse vaccination, human risk of exposure is dominated by the number of tick bites received per person, the proportion of tick blood meals taken from the highly reservoir-competent white-footed mouse relative to other hosts, and the average number of tick bites per mouse. Variation in these factors reduces the predictability of vaccination outcomes. Additionally, contributions of nonmouse hosts to pathogen maintenance preclude elimination of B. burgdorferi through mouse vaccination alone. Our findings indicate that to increase the impact of wildlife vaccination, reducing tick populations by acaricide application, in addition to targeting additional reservoir-competent host species, should be employed.

Rickettsia lusitaniae associated with Ornithodoros yumatensis (Acari: Argasidae) from two caves in Yucatan, Mexico.

PubMed

Sánchez-Montes, Sokani; Guzmán-Cornejo, Carmen; Martínez-Nájera, Yecenia; Becker, Ingeborg; Venzal, José M; Labruna, Marcelo B

2016-10-01

The genus Rickettsia includes obligate intracellular bacteria transmitted by several hematophagous arthropods such as ticks, fleas and sucking lice. In particular hard ticks (Ixodidae) have been cited as the main vectors of pathogenic rickettsiae in Mexico. However, there have been only two records of a single Rickettsia species associated with Mexican soft ticks (Argasidae). In this study, we searched for rickettsial DNA in argasid ticks (13 adults and eight nymphs of Ornithodoros yumatensis) from two bat caves in the state of Yucatan, Mexico. Additionally one larva collected in a cave from Chiapas, Mexico, and associated with Desmodus rotundus was used to corroborate the tick taxonomic determination. Of these, nine ticks (43%) yielded expected PCR products for the rickettsial gltA gene. These PCR-positive ticks were tested with additional PCR protocols targeting the rickettsial genes gltA, ompA and ompB. DNA partial sequences from these genes showed 99-100% identities with Rickettsia lusitaniae, an agent isolated from O. erraticus in Portugal, and closely related to R. felis and R. hoogstraalii. Based on the results from this study, the inventory of rickettsiae distributed in Mexico increases from six to seven species. Copyright © 2016 Elsevier GmbH. All rights reserved.

Ectoparasites and other epifaunistic arthropods of sympatric cotton mice and golden mice: comparisons and implications for vector-borne zoonotic diseases.

PubMed

Durden, Lance A; Polur, Ram N; Nims, Todd; Banks, Craig W; Oliver, James H

2004-12-01

Ectoparasite and epifaunistic arthropod biodiversity and infestation parameters were compared between 2 sympatric small rodent species, the cotton mouse (Peromyscus gossypinus (Le Conte)) and golden mouse (Ochrotomys nuttalli (Harlan)), in southern Georgia from 1992 to 2003. Because the cotton mouse is known to be a reservoir of more vector-borne zoonotic pathogens than the golden mouse, we hypothesized that it would be parasitized by more ectoparasites that are known to be vectors of these pathogens. Cotton mice (n = 202) were parasitized by 19 species of arthropods, whereas golden mice (n = 46) were parasitized by 12 species. Eleven species of arthropods were recovered from both host species, whereas 7 were recorded only from cotton mice, and 1 species only from golden mice. Infestation prevalences (percent of mice parasitized) were significantly higher for 1 species of arthropod (the tropical rat mite Ornithonyssus bacoti (Hirst)) infesting cotton mice and for 4 species (the flea Peromyscopsylla scotti Fox and the mites Glycyphagus hypudaei Koch, Androlaelaps casalis (Berlese), and Androlaelaps fahrenholzi (Berlese)) infesting golden mice. Mean intensities (mean per infested mouse) were significantly higher for 2 species (the flea Orchopeas leucopus (Baker) and the blacklegged tick Ixodes scapularis Say) infesting cotton mice and for 2 species (G. hypudaei and A. fahrenholzi) infesting golden mice. Ectoparasites that are known to be vectors of zoonotic pathogens were significantly more common on cotton mice than on golden mice. These ectoparasites included the rhopalopsyllid flea Polygenis gwyni (Fox), a vector of the agent of murine typhus; I. scapularis, the principal vector of the agents of Lyme borreliosis, human granulocytic ehrlichiosis, and human babesiosis; and O. bacoti, a laboratory vector of several zoonotic pathogens. However, 2 species of ixodid ticks that can transmit zoonotic pathogens were recovered from both host species. These were the American dog tick Dermacentor variabilis (Say), the principal vector of the agent of Rocky Mountain spotted fever in eastern North America, and Ixodes minor Neumann, an enzootic vector of the agent of Lyme borreliosis. Overall, the cotton mouse was parasitized by significantly more ectoparasites that are known to be vectors of zoonotic pathogens than was the golden mouse. These data support the hypothesis that the cotton mouse has greater epidemiological importance for zoonotic vector-borne pathogen transmission than does the golden mouse.

Tick-borne disease.

PubMed

Bratton, Robert L; Corey, Ralph

2005-06-15

Tick-borne diseases in the United States include Rocky Mountain spotted fever, Lyme disease, ehrlichiosis, tularemia, babesiosis, Colorado tick fever, and relapsing fever. It is important for family physicians to consider these illnesses when patients present with influenza-like symptoms. A petechial rash initially affecting the palms and soles of the feet is associated with Rocky Mountain spotted fever, whereas erythema migrans (annular macule with central clearing) is associated with Lyme disease. Various other rashes or skin lesions accompanied by fever and influenza-like illness also may signal the presence of a tick-borne disease. Early, accurate diagnosis allows treatment that may help prevent significant morbidity and possible mortality. Because 24 to 48 hours of attachment to the host are required for infection to occur, early removal can help prevent disease. Treatment with doxycycline or tetracycline is indicated for Rocky Mountain spotted fever, Lyme disease, ehrlichiosis, and relapsing fever. In patients with clinical findings suggestive of tick-borne disease, treatment should not be delayed for laboratory confirmation. If no symptoms follow exposure to tick bites, empiric treatment is not indicated. The same tick may harbor different infectious pathogens and transmit several with one bite. Advising patients about prevention of tick bites, especially in the summer months, may help prevent exposure to dangerous vector-borne diseases.

Molecular identification of tick-borne pathogens in ticks collected from dogs and small ruminants from Greece.

PubMed

Chaligiannis, Ιlias; Fernández de Mera, Isabel G; Papa, Anna; Sotiraki, Smaragda; de la Fuente, José

2018-04-01

Ticks are vectors for a variety of human and animal pathogens (bacteria, protozoa and viruses). In order to investigate the pathogens carried by ticks in Greece, a total of 179 adult ticks (114 female and 65 male) were collected from domestic animals (sheep, goats and dogs) from 14 prefectures of six regions of Greece. Among them, 40 were Dermacentor marginatus, 25 Haemaphysalis parva, 22 H. sulcata, one H. punctata, 13 Ixodes gibbosus, 77 Rhipicephalus sanguineus s.l. and one R. bursa. All ticks were tested for the presence of DNA of Anaplasma spp., Babesia spp., Coxiella burnetii, Rickettsia spp. and Theileria spp. The collected ticks were examined by PCR and reverse line blot (RLB) assay. A prevalence of 20.1% for Anaplasma spp., 15.6% for Babesia spp. (identifying B. bigemina, B. divergens, B. ovis and B. crassa), 17.9% for C. burnetii, 15.1% for Rickettsia spp., and 21.2% for Theileria spp. (identifying T. annulata, T. buffeli/orientalis, T. ovis and T. lestoquardi) was found. The results of this study demonstrate the variety of tick-borne pathogens of animal and human importance circulating in Greece, and that awareness is needed to minimize the risk of infection, especially among farmers and pet owners.

Detection of relapsing fever Borrelia spp., Bartonella spp. and Anaplasmataceae bacteria in argasid ticks in Algeria.

PubMed

Lafri, Ismail; El Hamzaoui, Basma; Bitam, Idir; Leulmi, Hamza; Lalout, Reda; Mediannikov, Oleg; Chergui, Mohamed; Karakellah, Mohamed; Raoult, Didier; Parola, Philippe

2017-11-01

Argasid ticks (soft ticks) are blood-feeding arthropods that can parasitize rodents, birds, humans, livestock and companion animals. Ticks of the Ornithodoros genus are known to be vectors of relapsing fever borreliosis in humans. In Algeria, little is known about relapsing fever borreliosis and other bacterial pathogens transmitted by argasid ticks. Between May 2013 and October 2015, we investigated the presence of soft ticks in 20 rodent burrows, 10 yellow-legged gull (Larus michahellis) nests and animal shelters in six locations in two different bioclimatic zones in Algeria. Six species of argasid ticks were identified morphologically and through 16S rRNA gene sequencing. The presence and prevalence of Borrelia spp., Bartonella spp., Rickettsia spp. and Anaplasmataceae was assessed by qPCR template assays in each specimen. All qPCR-positive samples were confirmed by standard PCR, followed by sequencing the amplified fragments. Two Borrelia species were identified: Borrelia hispanica in Ornithodoros occidentalis in Mostaganem, and Borrelia cf. turicatae in Carios capensis in Algiers. One new Bartonella genotype and one new Anaplasmataceae genotype were also identified in Argas persicus. The present study highlights the presence of relapsing fever borreliosis agents, although this disease is rarely diagnosed in Algeria. Other bacteria of unknown pathogenicity detected in argasid ticks which may bite humans deserve further investigation.

A Geographical Information System Based Approach for Integrated Strategies of Tick Surveillance and Control in the Peri-Urban Natural Reserve of Monte Pellegrino (Palermo, Southern Italy).

PubMed

Torina, Alessandra; Blanda, Valeria; Blanda, Marcellocalogero; Auteri, Michelangelo; La Russa, Francesco; Scimeca, Salvatore; D'Agostino, Rosalia; Disclafani, Rosaria; Villari, Sara; Currò, Vittoria; Caracappa, Santo

2018-02-27

Ticks (Acari: Ixodidae) are bloodsucking arthropods involved in pathogen transmission in animals and humans. Tick activity depends on various ecological factors such as vegetation, hosts, and temperature. The aim of this study was to analyse the spatial/temporal distribution of ticks in six sites within a peri-urban area of Palermo (Natural Reserve of Monte Pellegrino) and correlate it with field data using Geographical Information System (GIS) data. A total of 3092 ticks were gathered via dragging method from June 2012 to May 2014. The species collected were: Ixodes ventalloi (46.09%), Hyalomma lusitanicum (19.99%), Rhipicephalus sanguineus (17.34%), Rhipicephalus pusillus (16.11%), Haemaphisalis sulcata (0.36%), Dermacentor marginatus (0.10%), and Rhipicephalus turanicus (0.03%). GIS analysis revealed environmental characteristics of each site, and abundance of each tick species was analysed in relation to time (monthly trend) and space (site-specific abundance). A relevant presence of I. ventalloi in site 2 and H. lusitanicum in site 5 was observed, suggesting the possible exposure of animals and humans to tick-borne pathogens. Our study shows the importance of surveillance of ticks in peri-urban areas and the useful implementation of GIS analysis in vector ecology; studies on temporal and spatial distribution of ticks correlated to GIS-based ecological analysis represent an integrated strategy for decision support in public health.

Evaluation of 4-poster acaricide applicators to manage tick populations associated with disease risk in a Tennessee retirement community.

PubMed

Harmon, Jessica R; Hickling, Graham J; Scott, M Cathy; Jones, Carl J

2011-12-01

In 1993, four residents of a retirement community in middle Tennessee were hospitalized with symptoms of ehrlichiosis causing community managers to implement mitigation methods to reduce tick numbers. For the past four years, managers have utilized 4-poster acaricide applicators that aim to reduce disease risk to residents by killing ticks that feed on deer. To determine the efficacy of this technique, we assessed Amblyomma americanum abundance in the vicinity of the devices by dragging 400 m vegetation transects once per month while ticks were active. In 2009, adult tick activity peaked in May, nymphal tick activity peaked in June, and larval activity peaked in September. Close to 4-poster devices, larval, nymphal, and adult tick abundances were reduced by 91%, 68%, and 49%, respectively (larval and nymphal p<0.001, adult p=0.005), relative to nearby untreated areas. No significant reduction in nymphal or adult A. americanum ticks was evident >300 m from 4-poster devices, however a ∼90% reduction in larvae was observed to our sampling limit (400 m). At the low density at which these devices are currently being used (average distance between devices = 6.6 km), we conclude that they will have little large-scale effect on the health risk posed by ticks in this community. © 2011 The Society for Vector Ecology.

Tick fauna of Malaysian red jungle fowl (Gallus gallus) in Bangi, Malaysia.

PubMed

Konto, M; Fufa, G I; Zakaria, A; Tukur, S M; Watanabe, M; Ola-Fadunsin, S D; Khan, M S; Shettima, Y M; Babjee, S M A

2015-10-01

The red jungle fowl is generally considered as one of the endangered Asian wild Galleopheasants due to man-made encroachment of their habitats, coupled with the effect of disease and disease causing organisms like ticks and tick-borne infections. This study aimed to determine the tick fauna of the red jungle fowl and their predilection sites based on developmental stages. A total of 33 jungle fowls were sampled for this study from Bangi area of Selangor State, Peninsular Malaysian. The birds were captured using a locally made trap made-up of loops and bites. Ticks present on their bodies were detached using fine forceps and identified morphologically under a dissecting microscope. 91% of the jungle fowls were infested with ticks, all of which belongs to the species Haemaphysalis wellingtoni. The ear region appeared to be the most common predilection site (63%) for all the developmental stages in which the larval stages are solely restricted to that region. Nymphal and adult stages were distributed on the comb, wattle, and facial region in addition to the ear region. This study was the first in its kind and showed a high prevalence of tick infestation among jungle fowls. H. wellingtoni was known to be a vector in transmission of many tick-borne pathogens. Therefore, there is the need for further investigation to identify the various pathogens associated with this tick.

Tick fauna of Malaysian red jungle fowl (Gallus gallus) in Bangi, Malaysia

PubMed Central

Konto, M.; Fufa, G. I.; Zakaria, A.; Tukur, S. M.; Watanabe, M.; Ola-Fadunsin, S. D.; Khan, M. S.; Shettima, Y. M.; Babjee, S. M. A.

2015-01-01

Aim: The red jungle fowl is generally considered as one of the endangered Asian wild Galleopheasants due to man-made encroachment of their habitats, coupled with the effect of disease and disease causing organisms like ticks and tick-borne infections. This study aimed to determine the tick fauna of the red jungle fowl and their predilection sites based on developmental stages. Materials and Methods: A total of 33 jungle fowls were sampled for this study from Bangi area of Selangor State, Peninsular Malaysian. The birds were captured using a locally made trap made-up of loops and bites. Ticks present on their bodies were detached using fine forceps and identified morphologically under a dissecting microscope. Results: 91% of the jungle fowls were infested with ticks, all of which belongs to the species Haemaphysalis wellingtoni. The ear region appeared to be the most common predilection site (63%) for all the developmental stages in which the larval stages are solely restricted to that region. Nymphal and adult stages were distributed on the comb, wattle, and facial region in addition to the ear region. Conclusion: This study was the first in its kind and showed a high prevalence of tick infestation among jungle fowls. H. wellingtoni was known to be a vector in transmission of many tick-borne pathogens. Therefore, there is the need for further investigation to identify the various pathogens associated with this tick. PMID:27047012

Co-circulation of Crimean-Congo Hemorrhagic Fever virus strains Asia 1 and 2 between the border of Iran and Pakistan.

PubMed

Shahhosseini, Nariman; Jafarbekloo, Ahmad; Telmadarraiy, Zakkyeh; Chinikar, Sadegh; Haeri, Ali; Nowotny, Norbert; Groschup, Martin H; Fooks, Anthony R; Faghihi, Faezeh

2017-11-01

Crimean-Congo Hemorrhagic Fever (CCHF) is a tick-borne viral disease that is transmitted by numerous species of ticks, which serve both as a reservoir and vector of CCHF virus (CCHFV). Molecular and serological tests were undertaken on hard ticks (Ixodidae spp.) and samples from livestock were collected in 2015 from Chabahar County in Southeast Iran. Using RT-PCR, the ticks were tested for the presence of CCHFV. In addition, seven livestock were serologically tested for the presence of IgG antibodies using an ELISA test. IgG antibodies against CCHFV were detected in one of 7 of the livestock that were tested. In total, 49 ticks including five species: Rhipicephalus sanguineus, Hyalomma anatolicum , Hy. asiaticum, Hy. dromedarii and Hy. marginatum with a prevalence of 46.9%, 32.7%, 4.1%, 4.1% and 2.1% respectively were identified. CCHFV was detected in three ticks among 49 collected ticks. The ticks infected with CCHFV belonged to the genus Hyalomma and Rhipicephalus. Phylogenetic analysis demonstrated that two sequences clustered in clade IV (Asia-1) and one sequence was located within clade IV (Asia-2). Most of the animal and human CCHF cases of the country are reported from Sistan and Baluchistan provinces. Regular monitoring programs in the tick population and livestock are needed in the future.

Diversity and distribution of ticks from domestic ruminants in Lebanon.

PubMed

Dabaja, Mayssaa Fawaz; Tempesta, Maria; Bayan, Ali; Vesco, Gesualdo; Vesco, Gesualdo; Greco, Grazia; Torina, Alessandra; Blanda, Valeria; La Russa, Francesco; Scimeca, Salvatore; Ezzedine, Mohamad; Mortada, Hussein; Raoult, Didier; Fournier, Pierre Edouard; Mortada, Mohamad

2017-06-30

Ticks (Acari: Ixodidae) are ectoparasites infesting livestock in every geographic area in the world and they are vectors of several viral, bacterial, and protozoan pathogens to animals and humans worldwide. A deep knowledge of the geographical distribution of these arthropods would have a key role in the control of tick-borne diseases. Few data are available about tick presence in domestic ruminants in Lebanon. The study aimed at providing an analysis of tick presence and distribution in Lebanon. Ticks were collected from cattle, sheep, and goats farms distributed in 6 Lebanese provinces between June and September 2014. A total of 272 adult hard ticks were randomly collected from domestic ruminants (cattle, sheep, and goats) located at 37 Lebanese farms, distributed among 30 villages. Ticks belonged to 4 Ixodidae genera: Rhipicephalus (72.4%), Haemaphysalis (11.4%), Dermacentor (8.1%), and Hyalomma (8.1%). They included the following species: Rhipicephalus annulatus (50.7%), Rhipicephalus turanicus (18.8%), Hyalomma anatolicum (8.1%), Haemaphylasis punctata (11.4%), Dermacentor marginatus (8.1%), Rhipicephalus sanguineus (2.5%), and Rhipicephalus bursa (0.4%). Rhipicephalus turanicus and H. anatolicum were found on cattle, sheep, and goats, R. annulatus on cattle and sheep, R. sanguineus, D. marginatus and Hea. punctata on sheep and goats, while R. bursa was collected only on sheep. Tick species involved in pathogen transmission were found and some of the identi ed species were recorded in Lebanon for the rst time.

Crimean-Congo hemorrhagic fever virus in ticks in Turkey: A broad range tick surveillance study.

PubMed

Orkun, Ömer; Karaer, Zafer; Çakmak, Ayşe; Nalbantoğlu, Serpil

2017-08-01

In Turkey, Crimean-Congo hemorrhagic fever (CCHF) outbreaks started in northern regions in 2002. Human cases still continue to increase and the disease spreads in many other provinces of Turkey. The ecological role of the vector tick species occurring in Turkey is not certain exactly. Therefore, we planned a broad range tick study in three different ecological and geographical areas extending from the West Black Sea regions down to the Central Anatolia. The aim of this study was to determine and characterize CCHFV molecularly in feeding-ticks collected from various wild and domestic animals and from humans as well as in questing and unfed ticks. In this study, 4283 tick samples derived from 21 tick species were collected from 76 villages and 10 central districts in total. All tick pools were screened for the presence of CCHFV RNA by two nested RT-PCRs. PCR assays were positive for 27 (3.6%) of 736 pools. CCHFV was detected in Hyalomma marginatum, Dermacentor marginatus, Rhipicephalus bursa, Rhipicephalus turanicus, Hyalomma excavatum and Haemaphysalis parva pools. As a result of the phylogenetic analysis, it was determined that the obtained CCHFV sequences are clustered into Europe 1 clade. CCHFV was detected among ticks obtained from cattle, goats, wild boar, hare, and the ground. The presence of CCHFV in ticks obtained from various domestic and wild hosts and the nature, and thereby the distribution patterns of the virus in different ecological areas were presented in this study. Furthermore, CCHFV was also detected in unusual tick species. Consequently, these results indicate that tick surveillance studies in large-scale and wide varieties contribute to the ecology and epidemiology of CCHF in that region, and can be used as an early-warning system. Copyright © 2017 Elsevier B.V. All rights reserved.

Mitotic activity of the hemocytes in the tick Ixodes ricinus (Acari; Ixodidae).

PubMed

Kuhn, K H

1996-01-01

The blood cells, or hemocytes, of Ixodes ricinus have been shown to recognize, attack, and phagocytose microorganisms invading the body cavity, or hemocoel, of this tick. Regulated proliferation and differentiation of hemocytes, also referred to as immunocytes, is basic to an effective immune response to invading microorganisms. Therefore, this study dealt with hemopoiesis in I. ricinus, the vector tick of the Lyme disease spirochete Borrelia burgdorferi. Histological evidence for the presence of hemopoietic tissue, a preferential proliferation site of hemocytes, is presented. Mainly the mitotic activity of free-floating hemocytes was examined. By means of microscopical photometry and flow cytometry, all three types of hemocytes in engorging female I. ricinus were found in different stages of the cell cycle. In the engorging tick, up to 40% of the hemocytes counted were in the S phase or the G2/M phase. From this study we conclude that the differentiated hemocyte types do not differentiate from stem cells in the adult tick. Moreover, microorganisms entering the hemocoel of engorging ticks are confronted with high numbers of hemocytes and, therefore, with an effective cellular immune response.

VectorBase: a data resource for invertebrate vector genomics

PubMed Central

Lawson, Daniel; Arensburger, Peter; Atkinson, Peter; Besansky, Nora J.; Bruggner, Robert V.; Butler, Ryan; Campbell, Kathryn S.; Christophides, George K.; Christley, Scott; Dialynas, Emmanuel; Hammond, Martin; Hill, Catherine A.; Konopinski, Nathan; Lobo, Neil F.; MacCallum, Robert M.; Madey, Greg; Megy, Karine; Meyer, Jason; Redmond, Seth; Severson, David W.; Stinson, Eric O.; Topalis, Pantelis; Birney, Ewan; Gelbart, William M.; Kafatos, Fotis C.; Louis, Christos; Collins, Frank H.

2009-01-01

VectorBase (http://www.vectorbase.org) is an NIAID-funded Bioinformatic Resource Center focused on invertebrate vectors of human pathogens. VectorBase annotates and curates vector genomes providing a web accessible integrated resource for the research community. Currently, VectorBase contains genome information for three mosquito species: Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus, a body louse Pediculus humanus and a tick species Ixodes scapularis. Since our last report VectorBase has initiated a community annotation system, a microarray and gene expression repository and controlled vocabularies for anatomy and insecticide resistance. We have continued to develop both the software infrastructure and tools for interrogating the stored data. PMID:19028744

County-Scale Distribution of Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae) in the Continental United States

PubMed Central

Eisen, Rebecca J.; Eisen, Lars; Beard, Charles B.

2016-01-01

The blacklegged tick, Ixodes scapularis Say, is the primary vector to humans in the eastern United States of the Lyme disease spirochete Borrelia burgdorferi, as well as causative agents of anaplasmosis and babesiosis. Its close relative in the far western United States, the western blacklegged tick Ixodes pacificus Cooley and Kohls, is the primary vector to humans in that region of the Lyme disease and anaplasmosis agents. Since 1991, when standardized surveillance and reporting began, Lyme disease case counts have increased steadily in number and in geographical distribution in the eastern United States. Similar trends have been observed for anaplasmosis and babesiosis. To better understand the changing landscape of risk of human exposure to disease agents transmitted by I. scapularis and I. pacificus, and to document changes in their recorded distribution over the past two decades, we updated the distribution of these species from a map published in 1998. The presence of I. scapularis has now been documented from 1,420 (45.7%) of the 3,110 continental United States counties, as compared with 111 (3.6%) counties for I. pacificus. Combined, these vectors of B. burgdorferi and other disease agents now have been identified in a total of 1,531 (49.2%) counties spread across 43 states. This marks a 44.7% increase in the number of counties that have recorded the presence of these ticks since the previous map was presented in 1998, when 1,058 counties in 41 states reported the ticks to be present. Notably, the number of counties in which I. scapularis is considered established (six or more individuals or one or more life stages identified in a single year) has more than doubled since the previous national distribution map was published nearly two decades ago. The majority of county status changes occurred in the North-Central and Northeastern states, whereas the distribution in the South remained fairly stable. Two previously distinct foci for I. scapularis in the Northeast and North-Central states appear to be merging in the Ohio River Valley to form a single contiguous focus. Here we document a shifting landscape of risk for human exposure to medically important ticks and point to areas of re-emergence where enhanced vector surveillance and control may be warranted. PMID:26783367

Evaluation of the importance of VlsE antigenic variation for the enzootic cycle of borrelia burgdorferi

USDA-ARS?s Scientific Manuscript database

Efficient acquisition and transmission of Borrelia burgdorferi by the tick vector, and the ability to persistently infect both vector and host, are important elements for the life cycle of the Lyme disease pathogen. Previous work has provided strong evidence implicating the significance of the vls l...

Hepatozoon canis in German red foxes (Vulpes vulpes) and their ticks: molecular characterization and the phylogenetic relationship to other Hepatozoon spp.

PubMed

Najm, Nour-Addeen; Meyer-Kayser, Elisabeth; Hoffmann, Lothar; Pfister, Kurt; Silaghi, Cornelia

2014-07-01

In this study, the prevalence of Hepatozoon spp. in red foxes (Vulpes vulpes) and their ticks from Germany, as well as molecular characterizations and phylogenetic relationship to other Hepatozoon spp. were investigated. DNA extracts of 261 spleen samples and 1,953 ticks were examined for the presence of Hepatozoon spp. by a conventional polymerase chain reaction (PCR) targeting the 18S rRNA gene. The ticks included four tick species: Ixodes ricinus, Ixodes canisuga, Ixodes hexagonus and Dermacentor reticulatus. A total of 118/261 foxes (45.2%) and 148/1,953 ticks (7.5%) were Hepatozoon PCR-positive. Amplicons from 36 positive foxes and 41 positive ticks were sequenced. All sequences obtained from foxes and 39/41 from ticks had a 99% similarity to Hepatozoon canis, whereas two ticks' sequences had a 99% identity to Hepatozoon sp. The obtained Hepatozoon sequences in this study were phylogenetically related to other Hepatozoon sequences detected in other countries, which may represent strain variants. The high prevalence of H. canis DNA in red foxes in this study supports the suggested role of those animals in distribution of this parasite. Furthermore, detection of DNA of H. canis in foxes and all examined tick species collected from those foxes allows speculating about previously undescribed potential vectors for H. canis and suggests a potential role of the red fox in its natural endemic cycles.

Rickettsiaceae and Anaplasmataceae infections in Ixodes ricinus ticks from urban and natural forested areas of Poland

PubMed Central

2014-01-01

Background Ixodes ricinus is a major vector for a range of microbial pathogens and the most prevalent and widely distributed tick species on the European continent, occurring in both natural and urban habitats. Nevertheless, little is known about the relative density of ticks in these two ecologically distinct habitats and the diversity of tick-borne pathogens that they carry. Methods We compared densities of questing I. ricinus nymphs and adults in urban and natural habitats in Central and Northeastern Poland, assessed the prevalence and rate of co-infection with A. phagocytophilum, Rickettsia, Ehrlichia and ‘Ca. Neoehrlichia spp.’ in ticks, and compared the diversity of tick-borne pathogens using molecular assays (PCR). Results Of the 1325 adults and nymphs, 6.2% were infected with at least one pathogen, with 4.4%, 1.7% and less than 0.5% being positive for the DNA of Rickettsia spp., A. phagocytophilum, Ehrlichia spp. and Ca. N. mikurensis, respectively. Although tick abundance was higher in natural habitats, the prevalence of the majority of pathogens was higher in urban forested areas. Conclusion We conclude that: (i) zoonotic genetic variants of A. phagocytophilum are widely distributed in the Polish tick population, (ii) although the diversity of tick borne pathogens was higher in natural habitats, zoonotic species/strains were detected only in urban forests, (iii) and we provide the first description of Ca. N. mikurensis infections in ticks in Poland. PMID:24661311

Epidemiology of Tick-Borne Borreliosis in Morocco

PubMed Central

Diatta, Georges; Souidi, Yassine; Granjon, Laurent; Arnathau, Céline; Durand, Patrick; Chauvancy, Gilles; Mané, Youssouph; Sarih, M'hammed; Belghyti, Driss; Renaud, François; Trape, Jean-François

2012-01-01

Background The presence in Morocco of Argasid ticks of the Ornithodoros erraticus complex, the vector of tick-borne relapsing fever (TBRF) in North Africa, has been known since 1919, but the disease is rarely diagnosed and few epidemiological data are available. Methodology/Principal Findings Between 2006 and 2011, we investigated the presence of Ornithodoros ticks in rodent burrows in 34 sites distributed across Morocco. We also collected small mammals in 10 sites and we investigated TBRF in febrile patients in Kenitra district. The prevalence of Borrelia infections was assessed by nested PCR amplification in ticks and the brain tissue of small mammals, and by evaluation of thick blood films in patients. A high proportion of burrows were infested with ticks of the O. erraticus complex in all regions of Morocco, with a mean of 39.5% for the whole country. Borrelia infections were found in 39/382 (10.2%) of the ticks and 12/140 (8.6%) of the rodents and insectivores studied by PCR amplification, and 102 patients tested positive by thick blood film. Five small mammalian species were found infected: Dipodillus campestris, Meriones shawi, Gerbillus hoogstrali, Gerbillus occiduus and Atelerix algirus. Three Borrelia species were identified in ticks and/or rodents: B. hispanica, B. crocidurae and B. merionesi. Conclusions/Significance Tick populations belonging to O. erraticus complex are widely distributed in Morocco and a high proportion of ticks and small mammals are infected by Borrelia species. Although rarely diagnosed, TBRF may be a common cause of morbidity in all regions of Morocco. PMID:23029574

Oocysts of Hepatozoon canis in Rhipicephalus (Boophilus) microplus collected from a naturally infected dog.

PubMed

de Miranda, Renata Lima; de Castro, Jacqueline Ribeiro; Olegário, Maria Marlene Martins; Beletti, Marcelo Emílio; Mundim, Antonio Vicente; O'Dwyer, Lucia Helena; Eyal, Osnat; Talmi-Frank, Dalit; Cury, Márcia Cristina; Baneth, Gad

2011-05-11

Canine hepatozoonosis is a tick-borne disease caused by protozoans of the genus Hepatozoon. Several tick species have been implicated as potential vectors. Therefore, extensive studies are needed to determine the 'natural' endemic cycle of this parasite. This paper presents the first report of the presence of Hepatozoon canis oocysts in Rhipicephalus (Boophilus) microplus collected from an infected dog. Copyright © 2011 Elsevier B.V. All rights reserved.

Rhipicephalus sanguineus (ACARI: IXODIDAE) BITING A HUMAN BEING IN PORTO ALEGRE CITY, RIO GRANDE DO SUL, BRAZIL

PubMed Central

MENTZ, Márcia Bohrer; TROMBKA, Marcelo; da SILVA, Guilherme Liberato; SILVA, Carlos Eugênio

2016-01-01

We report the finding of a female brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae) on the scalp of a male patient in Porto Alegre, Rio Grande do Sul, Brazil. Human parasitism by this tick is rare and has seldomly been reported in the literature, despite its recognized importance since it can act as a vector of Rickettsia rickettsii, the agent of spotted fever. PMID:27074329

Rhipicephalus sanguineus (ACARI: IXODIDAE) BITING A HUMAN BEING IN PORTO ALEGRE CITY, RIO GRANDE DO SUL, BRAZIL.

PubMed

Mentz, Márcia Bohrer; Trombka, Marcelo; Silva, Guilherme Liberato da; Silva, Carlos Eugênio

2016-01-01

We report the finding of a female brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae) on the scalp of a male patient inPorto Alegre, Rio Grande do Sul, Brazil. Human parasitism by this tick is rare and has seldomly been reported in the literature, despite its recognized importance since it can act as a vector of Rickettsia rickettsii, the agent of spotted fever.

Co-feeding transmission facilitates strain coexistence in Borrelia burgdorferi, the Lyme disease agent.

PubMed

States, S L; Huang, C I; Davis, S; Tufts, D M; Diuk-Wasser, M A

2017-06-01

Coexistence of multiple tick-borne pathogens or strains is common in natural hosts and can be facilitated by resource partitioning of the host species, within-host localization, or by different transmission pathways. Most vector-borne pathogens are transmitted horizontally via systemic host infection, but transmission may occur in the absence of systemic infection between two vectors feeding in close proximity, enabling pathogens to minimize competition and escape the host immune response. In a laboratory study, we demonstrated that co-feeding transmission can occur for a rapidly-cleared strain of Borrelia burgdorferi, the Lyme disease agent, between two stages of the tick vector Ixodes scapularis while feeding on their dominant host, Peromyscus leucopus. In contrast, infections rapidly became systemic for the persistently infecting strain. In a field study, we assessed opportunities for co-feeding transmission by measuring co-occurrence of two tick stages on ears of small mammals over two years at multiple sites. Finally, in a modeling study, we assessed the importance of co-feeding on R 0 , the basic reproductive number. The model indicated that co-feeding increases the fitness of rapidly-cleared strains in regions with synchronous immature tick feeding. Our results are consistent with increased diversity of B. burgdorferi in areas of higher synchrony in immature feeding - such as the midwestern United States. A higher relative proportion of rapidly-cleared strains, which are less human pathogenic, would also explain lower Lyme disease incidence in this region. Finally, if co-feeding transmission also occurs on refractory hosts, it may facilitate the emergence and persistence of new pathogens with a more limited host range. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

A Review of African Swine Fever and the Potential for Introduction into the United States and the Possibility of Subsequent Establishment in Feral Swine and Native Ticks.

PubMed

Brown, Vienna R; Bevins, Sarah N

2018-01-01

African swine fever (ASF) is caused by African swine fever virus (ASFV), which can cause substantial morbidity and mortality events in swine. The virus can be transmitted via direct and indirect contacts with infected swine, their products, or competent vector species, especially Ornithodoros ticks. Africa and much of Eastern Europe are endemic for ASF; a viral introduction to countries that are currently ASF free could have severe economic consequences due to the loss of production from infected animals and the trade restrictions that would likely be imposed as a result of an outbreak. We identified vulnerabilities that could lead to ASFV introduction or persistence in the United States or other ASF-free regions. Both legal and illegal movements of live animals, as well as the importation of animal products, byproducts, and animal feed, pose a risk of virus introduction. Each route is described, and current regulations designed to prevent ASFV and other pathogens from entering the United States are outlined. Furthermore, existing ASFV research gaps are highlighted. Laboratory experiments to evaluate multiple species of Ornithodoros ticks that have yet to be characterized would be useful to understand vector competence, host preferences, and distribution of competent soft tick vectors in relation to high pig production areas as well as regions with high feral swine (wild boar or similar) densities. Knowledge relative to antigenic viral proteins that contribute to host response and determination of immune mechanisms that lead to protection are foundational in the quest for a vaccine. Finally, sampling of illegally imported and confiscated wild suid products for ASFV could shed light on the types of products being imported and provide a more informed perspective relative to the risk of ASFV importation.

A Review of African Swine Fever and the Potential for Introduction into the United States and the Possibility of Subsequent Establishment in Feral Swine and Native Ticks

PubMed Central

Brown, Vienna R.; Bevins, Sarah N.

2018-01-01

African swine fever (ASF) is caused by African swine fever virus (ASFV), which can cause substantial morbidity and mortality events in swine. The virus can be transmitted via direct and indirect contacts with infected swine, their products, or competent vector species, especially Ornithodoros ticks. Africa and much of Eastern Europe are endemic for ASF; a viral introduction to countries that are currently ASF free could have severe economic consequences due to the loss of production from infected animals and the trade restrictions that would likely be imposed as a result of an outbreak. We identified vulnerabilities that could lead to ASFV introduction or persistence in the United States or other ASF-free regions. Both legal and illegal movements of live animals, as well as the importation of animal products, byproducts, and animal feed, pose a risk of virus introduction. Each route is described, and current regulations designed to prevent ASFV and other pathogens from entering the United States are outlined. Furthermore, existing ASFV research gaps are highlighted. Laboratory experiments to evaluate multiple species of Ornithodoros ticks that have yet to be characterized would be useful to understand vector competence, host preferences, and distribution of competent soft tick vectors in relation to high pig production areas as well as regions with high feral swine (wild boar or similar) densities. Knowledge relative to antigenic viral proteins that contribute to host response and determination of immune mechanisms that lead to protection are foundational in the quest for a vaccine. Finally, sampling of illegally imported and confiscated wild suid products for ASFV could shed light on the types of products being imported and provide a more informed perspective relative to the risk of ASFV importation. PMID:29468165

[Natural infection by hemoparasites in calves submitted to chemoprophylaxis at 30 days of age].

PubMed

da Silva, Rosângela A; Corrêa, Fabíola do N; Botteon, Rita de Cássia C M; Botteon, Paulo de Tarso L

2007-01-01

The tick-borne disease (TBD) brings great damages to cattle breeding. The most important etiologic agents are Babesia bigemina, B. bovis and Anaplasma marginale, being the tick Boophilus microplus the main vector. This work reports the occurrence of natural infection by hemoparasites of TBD in 36 calves with high ticks natural infestation submitted to chemoprophylaxis with 30 days year-old. The blood smears from animals of different ages were analized and were found B. bigemina (33.3%), B. bovis (11.1%) and A. marginale (13.9%). Six animals had clinical symptoms (16.7%) and one dead (2.8%). The number of clinical cases ocurred in consequence of an association of factors as high infestation of ticks and low passive immunity in period that calves had not developed enough active immunity.

Factors affecting the ecology of tick-borne encephalitis in Slovenia.

PubMed

Knap, N; Avšič-Županc, T

2015-07-01

Recognition of factors that influence the formation of tick-borne encephalitis (TBE) foci is important for assessing the risk of humans acquiring the viral infection and for establishing what can be done (within reasonable boundaries) to minimize that risk. In Slovenia, the dynamics of the TBE vector, i.e. Ixodes ricinus, was studied over a 4-year period and the prevalence of infection in ticks was established. Two groups of tick hosts were investigated: deer and small mammals. Red deer have been confirmed as having a direct influence on the incidence of TBE and rodents have been recognized as important sentinels for TBE infections, although their role in the enzootic cycle of the virus still remains to be elucidated. Last, forest and agricultural areas, which are influenced by human activity, are suitable habitats for ticks, and important for TBEV transmission and establishment. Human behaviour is also therefore an important factor and should always be considered in studies of TBE ecology.

Integrated metatranscriptomics and metaproteomics for the characterization of bacterial microbiota in unfed Ixodes ricinus.

PubMed

Hernández-Jarguín, Angélica; Díaz-Sánchez, Sandra; Villar, Margarita; de la Fuente, José

2018-05-05

An innovative metaomics approach integrating metatranscriptomics and metaproteomics was used to characterize bacterial communities in the microbiota of the Lyme borreliosis spirochete vector, Ixodes ricinus (Acari: Ixodidae). Whole internal tissues and salivary glands from unfed larvae and female ticks, respectively were used. Reused I. ricinus RNA-sequencing data for metranscriptomics analysis together with metaproteomics provided a better characterization of tick bacterial microbiota by increasing bacteria identification and support for identified bacteria with putative functional implications. The results showed the presence of symbiotic, commensal, soil, environmental, and pathogenic bacteria in the I. ricinus microbiota, including previously unrecognized commensal and soil microorganisms. The results of the metaomics approach may have implications in the characterization of putative mechanisms by which pathogen infection manipulates tick microbiota to facilitate infection. Metaomics approaches integrating different omics datasets would provide a better description of tick microbiota compositions, and insights into tick interactions with microbiota, pathogens and hosts. Copyright © 2018 Elsevier GmbH. All rights reserved.

Top-Down-Assisted Bottom-Up Method for Homologous Protein Sequencing: Hemoglobin from 33 Bird Species

NASA Astrophysics Data System (ADS)

Song, Yang; Laskay, Ünige A.; Vilcins, Inger-Marie E.; Barbour, Alan G.; Wysocki, Vicki H.

2015-11-01

Ticks are vectors for disease transmission because they are indiscriminant in their feeding on multiple vertebrate hosts, transmitting pathogens between their hosts. Identifying the hosts on which ticks have fed is important for disease prevention and intervention. We have previously shown that hemoglobin (Hb) remnants from a host on which a tick fed can be used to reveal the host's identity. For the present research, blood was collected from 33 bird species that are common in the U.S. as hosts for ticks but that have unknown Hb sequences. A top-down-assisted bottom-up mass spectrometry approach with a customized searching database, based on variability in known bird hemoglobin sequences, has been devised to facilitate fast and complete sequencing of hemoglobin from birds with unknown sequences. These hemoglobin sequences will be added to a hemoglobin database and used for tick host identification. The general approach has the potential to sequence any set of homologous proteins completely in a rapid manner.

Molecular detection of the human pathogenic Rickettsia sp. strain Atlantic rainforest in Amblyomma dubitatum ticks from Argentina.

PubMed

Monje, Lucas D; Nava, Santiago; Eberhardt, Ayelen T; Correa, Ana I; Guglielmone, Alberto A; Beldomenico, Pablo M

2015-02-01

To date, three tick-borne pathogenic Rickettsia species have been reported in different regions of Argentina, namely, R. rickettsii, R. parkeri, and R. massiliae. However, there are no reports available for the presence of tick-borne pathogens from the northeastern region of Argentina. This study evaluated the infection with Rickettsia species of Amblyomma dubitatum ticks collected from vegetation and feeding from capybaras (Hydrochoerus hydrochaeris) in northeastern Argentina. From a total of 374 A. dubitatum ticks collected and evaluated by PCR for the presence of rickettsial DNA, 19 were positive for the presence of Rickettsia bellii DNA, two were positive for Rickettsia sp. strain COOPERI, and one was positive for the pathogenic Rickettsia sp. strain Atlantic rainforest. To our knowledge, this study is the first report of the presence of the human pathogen Rickettsia sp. strain Atlantic rainforest and Rickettsia sp. strain COOPERI in Argentina. Moreover, our findings posit A. dubitatum as a potential vector for this pathogenic strain of Rickettsia.

Ticks circulate Anaplasma, Ehrlichia, Babesia and Theileria parasites in North of Iran.

PubMed

Bekloo, Ahmad Jafar; Bakhshi, Hasan; Soufizadeh, Ayoub; Sedaghat, Mohammad Mehdi; Bekloo, Romina Jafar; Ramzgouyan, Maryam Roya; Chegeni, Asadollah Hosseini; Faghihi, Faezeh; Telmadarraiy, Zakkyeh

2017-12-15

Ticks serve as important vectors of some pathogens of medical importance all over the world and identification of their rate of infection plays an important role for further control of diseases. In the current study, we investigated on ticks collected from north of Iran where raising and caring livestock are the main task of the people in order to find evidences of infection of Babesia, Theileria, Anaplasma and Ehrlichia microbial agents. Totally, 609 hard tick species from two genera Hyalomma and Rhipicephalus including; Hy. scupense, Hy. dromedarii, Hy. rufipes, Hy. marginatum, Hy. asiaticum, Hy. anatolicum, R. bursa, R. sanguineus and R. turanicus were identified. Molecular analysis revealed the presence of Anaplasma, Ehrlichia, Babesia and Theileria microorganism agents in all collected tick species except Hy. asiaticum and R. turanicus. To the best of our knowledge, this is the first report on identification of B. occultans in Hyalomma anatolicum and B. ovis in Hyalomma sp in Iran. Copyright © 2017 Elsevier B.V. All rights reserved.

[Crimean-Congo Hemorrhagic Fever].

PubMed

Güneş, Turabi

2006-07-01

Crimean-Congo Hemorrhagic Fever (CCHF) virus is a tick-borne virus, which is a member of Bunyaviridae family, Nairovirus genus. CCHF virus has been isolated from 31 different tick species so far, and genus Hyalomma includes the basic vectors of which H. anatolicum, H. marginatum, H. detritum, H. dromedarii, H. excavatum and H. turanicum are frequently found in the geography in which Turkey takes place. The virus is transmitted via the bite of infected ticks or direct contact with CCHF infected patients and the products of infected animals. Following 2-9 days incubation period, the disease abruptly starts with fever, feeling cold, shivering, headache, muscle and joint aches. After a few days hemorrhage develops at various parts of the body. Since an effective vaccine and a specific antiviral therapy have not been found yet, the high mortality rate which may reach to 10-60%, and a wide geography affecting approximately 40 countries including Turkey, CCHF attracts the attention of both scientific and mediatic world, in recent years. In this article, the structure, vectors and reservoirs of CCHF virus, together with the epidemiology, clinical features, laboratory diagnosis and strategies of treatment and prevention, have been reviewed.

Emerging Vector-Borne Diseases.

PubMed

Huntington, Mark K; Allison, Jay; Nair, Dilip

2016-10-01

Several mosquito-borne viral infections have recently emerged in North America; West Nile virus is the most common in the United States. Although West Nile virus generally causes a self-limited, flulike febrile illness, a serious neuroinvasive form may occur. Dengue is the most common vector-borne viral disease worldwide, and it has been a significant public health threat in the United States since 2009. Known as breakbone fever for its severe myalgias and arthralgias, dengue may cause a hemorrhagic syndrome. Chikungunya also causes flulike febrile illness and disabling arthralgias. Although meningoencephalitis may occur with chikungunya, bleeding is uncommon. Symptoms of Zika virus infection are similar to those of dengue, but milder. Zika virus increases the risk of fetal brain abnormalities, including microcephaly, if a pregnant woman is infected. Zika virus is spread through Aedes albopictus mosquito bites, is transmitted sexually, and may rarely spread nonsexually from person to person. Diagnosis of these vectorborne infections is clinical and serologic, and treatment is supportive. Other, well-established vector-borne diseases are also important. Ehrlichiosis is a tick-borne bacterial disease that presents as a nonspecific syndrome of fever, headache, malaise, and myalgias. It is diagnosed via blood smear testing, with confirmatory serology. Ehrlichiosis is treated with doxycycline. Rickettsial infections are transmitted by fleas, mites, and ticks, and severity ranges from mild to life threatening. Rocky Mountain spotted fever, the most significant rickettsial infection, is primarily a clinical diagnosis that presents as fever, headache, myalgias, petechial rash, and tick exposure. Doxycycline is effective for rickettsial infections if administered promptly. Vector avoidance strategies are critical to the prevention of all of these infections.

Avian migrants facilitate invasions of neotropical ticks and tick-borne pathogens into the United States.

PubMed

Cohen, Emily B; Auckland, Lisa D; Marra, Peter P; Hamer, Sarah A

2015-12-01

Migratory birds have the potential to transport exotic vectors and pathogens of human and animal health importance across vast distances. We systematically examined birds that recently migrated to the United States from the Neotropics for ticks. We screened both ticks and birds for tick-borne pathogens, including Rickettsia species and Borrelia burgdorferi. Over two spring seasons (2013 and 2014), 3.56% of birds (n = 3,844) representing 42.35% of the species examined (n = 85) were infested by ticks. Ground-foraging birds with reduced fuel stores were most commonly infested. Eight tick species were identified, including seven in the genus Amblyomma, of which only Amblyomma maculatum/Amblyomma triste is known to be established in the United States. Most ticks on birds (67%) were neotropical species with ranges in Central and South America. Additionally, a single Ixodes genus tick was detected. A total of 29% of the ticks (n = 137) and no avian blood samples (n = 100) were positive for infection with Rickettsia species, including Rickettsia parkeri, an emerging cause of spotted fever in humans in the southern United States, a species in the group of Rickettsia monacensis, and uncharacterized species and endosymbionts of unknown pathogenicity. No avian tick or blood samples tested positive for B. burgdorferi, the etiologic agent of Lyme disease. An extrapolation of our findings suggests that anywhere from 4 to 39 million exotic neotropical ticks are transported to the United States annually on migratory songbirds, with uncertain consequences for human and animal health if the current barriers to their establishment and spread are overcome. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Multiflora rose invasion amplifies prevalence of Lyme disease pathogen, but not necessarily Lyme disease risk.

PubMed

Adalsteinsson, Solny A; Shriver, W Gregory; Hojgaard, Andrias; Bowman, Jacob L; Brisson, Dustin; D'Amico, Vincent; Buler, Jeffrey J

2018-01-23

Forests in urban landscapes differ from their rural counterparts in ways that may alter vector-borne disease dynamics. In urban forest fragments, tick-borne pathogen prevalence is not well characterized; mitigating disease risk in densely-populated urban landscapes requires understanding ecological factors that affect pathogen prevalence. We trapped blacklegged tick (Ixodes scapularis) nymphs in urban forest fragments on the East Coast of the United States and used multiplex real-time PCR assays to quantify the prevalence of four zoonotic, tick-borne pathogens. We used Bayesian logistic regression and WAIC model selection to understand how vegetation, habitat, and landscape features of urban forests relate to the prevalence of B. burgdorferi (the causative agent of Lyme disease) among blacklegged ticks. In the 258 nymphs tested, we detected Borrelia burgdorferi (11.2% of ticks), Borrelia miyamotoi (0.8%) and Anaplasma phagocytophilum (1.9%), but we did not find Babesia microti (0%). Ticks collected from forests invaded by non-native multiflora rose (Rosa multiflora) had greater B. burgdorferi infection rates (mean = 15.9%) than ticks collected from uninvaded forests (mean = 7.9%). Overall, B. burgdorferi prevalence among ticks was positively related to habitat features (e.g. coarse woody debris and total understory cover) favorable for competent reservoir host species. Understory structure provided by non-native, invasive shrubs appears to aggregate ticks and reservoir hosts, increasing opportunities for pathogen transmission. However, when we consider pathogen prevalence among nymphs in context with relative abundance of questing nymphs, invasive plants do not necessarily increase disease risk. Although pathogen prevalence is greater among ticks in invaded forests, the probability of encountering an infected tick remains greater in uninvaded forests characterized by thick litter layers, sparse understories, and relatively greater questing tick abundance in urban landscapes.

Bioassays to evaluate non-contact spatial repellency, contact irritancy, and acute toxicity of permethrin-treated clothing against nymphal Ixodes scapularis ticks.

PubMed

Eisen, Lars; Rose, Dominic; Prose, Robert; Breuner, Nicole E; Dolan, Marc C; Thompson, Karen; Connally, Neeta

2017-10-01

Summer-weight clothing articles impregnated with permethrin are available as a personal protective measure against human-biting ticks in the United States. However, very few studies have addressed the impact of contact with summer-weight permethrin-treated textiles on tick vigor and behavior. Our aim was to generate new knowledge of how permethrin-treated textiles impact nymphal Ixodes scapularis ticks, the primary vectors in the eastern United States of the causative agents of Lyme disease, human anaplasmosis, and human babesiosis. We developed a series of bioassays designed to: (i) clarify whether permethrin-treated textiles impact ticks through non-contact spatial repellency or contact irritancy; (ii) evaluate the ability of ticks to remain in contact with vertically oriented permethrin-treated textiles, mimicking contact with treated clothing on arms or legs; and (iii) determine the impact of timed exposure to permethrin-treated textiles on the ability of ticks to move and orient toward a human finger stimulus, thus demonstrating normal behavior. Our results indicate that permethrin-treated textiles provide minimal non-contact spatial repellency but strong contact irritancy against ticks, manifesting as a "hot-foot" effect and resulting in ticks actively dislodging from contact with vertically oriented treated textile. Preliminary data suggest that the contact irritancy hot-foot response may be weaker for field-collected nymphs as compared with laboratory-reared nymphs placed upon permethrin-treated textile. We also demonstrate that contact with permethrin-treated textiles negatively impacts the vigor and behavior of nymphal ticks for >24h, with outcomes ranging from complete lack of movement to impaired movement and unwillingness of ticks displaying normal movement to ascend onto a human finger. The protective effect of summer-weight permethrin-treated clothing against tick bites merits further study. Published by Elsevier GmbH.

The dog factor in brown dog tick Rhipicephalus sanguineus (Acari: Ixodidae) infestations in and near human dwellings.

PubMed

Uspensky, Igor; Ioffe-Uspensky, Inna

2002-06-01

Three cases of the tick Rhipicephalus sanguineus infiltration in or near human dwellings caused by dogs, and their influence on epidemiological features of human habitats have been investigated. (a) The observation of dogs kept indoors proved that single tick females could engorge and oviposit inside apartments followed by the development of subadults. (b) Abundant micropopulations of ticks were formed in small yards or gardens near the dwellings where dogs lived in kennels. (c) A huge field population of R. sanguineus was observed on a farm where watchdogs constantly patrolled along the farm perimeter. Tick abundance near the kennels and in the permanent resting sites of the dogs reached more than 30 adults per 10 min of collecting, while the number of adults on a dog reached 100. Unfed adult females under conditions of constant dog availability had a larger scutal index than females collected in the control field site. On the basis of circumstantial evidence it is possible to conclude that under the above conditions tick development may change from the normal 3-host cycle to a 2-host cycle. Ticks in the field had one complete generation per year. Ticks on the farm, as well as ticks in kennels, developed faster and a significant part of their population had two complete generations per year. R. sanguineus is the main vector and reservoir of a pathogen from the Rickettsia conorii complex, the causative agent of Israeli tick typhus. The described conglomerations of R. sanguineus create a great risk to humans who can be attacked by infected ticks in and around their homes, even in large towns. Such a feature of the tick life history most likely exists not only in Israel but in other countries as well.

Molecular detection of emerging tick-borne pathogens in Vojvodina, Serbia.

PubMed

Potkonjak, Aleksandar; Gutiérrez, Ricardo; Savić, Sara; Vračar, Vuk; Nachum-Biala, Yaarit; Jurišić, Aleksandar; Kleinerman, Gabriela; Rojas, Alicia; Petrović, Aleksandra; Baneth, Gad; Harrus, Shimon

2016-02-01

Ticks play an important role in disease transmission globally due to their capability to serve as vectors for human and animal pathogens. The Republic of Serbia is an endemic area for a large number of tick-borne diseases. However, current knowledge on these diseases in Serbia is limited. The aim of this study was to investigate the presence of new emerging tick-borne pathogens in ticks collected from dogs and the vegetation from different parts of Vojvodina, Serbia. A total of 187 ticks, including 124 Rhipicephalus sanguineus, 45 Ixodes ricinus and 18 Dermacentor reticulatus were collected from dogs. In addition, 26 questing I. ricinus ticks were collected from the vegetation, using the flagging method, from 4 different localities in Vojvodina, Serbia. DNA was extracted from each tick individually and samples were tested by either conventional or real-time PCR assays for the presence of Rickettsia spp.-DNA (gltA and ompA gene fragments), Ehrlichia/Anaplasma spp.-DNA (16S rRNA gene fragment) and Hepatozoon spp./Babesia spp.-DNA (18S rRNA gene fragment). In addition, all I. ricinus DNA samples were tested for Bartonella spp.-DNA (ITS locus) by real-time PCR. In this study, the presence of novel emerging tick-borne pathogens including Rickettsia raoultii, Rickettsia massiliae, Babesia venatorum, Babesia microti, Hepatozoon canis and Candidatus Neoehrlichia mikurensis was identified for the first time in Serbia. Our findings also confirmed the presence of Rickettsia monacensis, Babesia canis and Anaplasma phagocytophilum in ticks from Serbia. The findings of the current study highlight the great diversity of tick-borne pathogens of human and animal importance in Serbia. Physicians, public health workers and veterinarians should increase alertness to the presence of these tick-borne pathogens in this country. Copyright © 2015 Elsevier GmbH. All rights reserved.

Morphological effects of neem (Azadirachta indica A. Juss) seed oil with known azadirachtin concentrations on the oocytes of semi-engorged Rhipicephalus sanguineus ticks (Acari: Ixodidae).

PubMed

Remedio, R N; Nunes, P H; Anholeto, L A; Oliveira, P R; Camargo-Mathias, M I

2015-02-01

The concern about the harmful effects caused by synthetic pesticides has led to the search for safe and ecological alternatives for pest control. In this context, the neem tree (Azadirachta indica) stands out due to its repellent properties and effects on various arthropods, including ticks. For this reason, this study aimed to demonstrate the potential of neem as a control method for Rhipicephalus sanguineus ticks, important vectors of diseases in the veterinary point of view. For this, R. sanguineus semi-engorged females were subjected to treatment with neem seed oil enriched with azadirachtin, its main compound, and ovaries were assessed by means of morphological techniques in conventional light microscopy, confocal laser scanning microscopy, and transmission electron microscopy. Neem demonstrated a clear dose-dependent effect in the analyzed samples. The observed oocytes presented, especially in the groups treated with higher concentrations of neem oil, obvious signs of cytoplasmic disorganization, cellular vacuolization, nuclear and nucleolar irregularity, dilation in mitochondrial cristae, alterations in mitochondrial matrix, and swelling of rough endoplasmic reticulum. Intracellular microorganisms were observed in all analyzed groups, reinforcing the importance of ticks in the transmission of pathogens. A greater quantity of microorganisms was noted as the concentration of neem increased, indicating that the damaged oocytes may be more susceptible for their development. Such morphological alterations may promote future damages in reproductive performance of these animals and demonstrate the potential of neem seed oil for the control of R. sanguineus ticks, paving the way for new, cheaper, and safer methods of control.

A multi-level analysis of the relationship between environmental factors and questing Ixodes ricinus dynamics in Belgium

PubMed Central

2012-01-01

Background Ticks are the most important pathogen vectors in Europe. They are known to be influenced by environmental factors, but these links are usually studied at specific temporal or spatial scales. Focusing on Ixodes ricinus in Belgium, we attempt to bridge the gap between current “single-sided” studies that focus on temporal or spatial variation only. Here, spatial and temporal patterns of ticks are modelled together. Methods A multi-level analysis of the Ixodes ricinus patterns in Belgium was performed. Joint effects of weather, habitat quality and hunting on field sampled tick abundance were examined at two levels, namely, sampling level, which is associated with temporal dynamics, and site level, which is related to spatial dynamics. Independent variables were collected from standard weather station records, game management data and remote sensing-based land cover data. Results At sampling level, only a marginally significant effect of daily relative humidity and temperature on the abundance of questing nymphs was identified. Average wind speed of seven days prior to the sampling day was found important to both questing nymphs and adults. At site level, a group of landscape-level forest fragmentation indices were highlighted for both questing nymph and adult abundance, including the nearest-neighbour distance, the shape and the aggregation level of forest patches. No cross-level effects or spatial autocorrelation were found. Conclusions Nymphal and adult ticks responded differently to environmental variables at different spatial and temporal scales. Our results can advise spatio-temporal extents of environment data collection for continuing empirical investigations and potential parameters for biological tick models. PMID:22830528

Incorporating NDVI in a gravity model setting to describe spatio-temporal patterns of Lyme borreliosis incidence

NASA Astrophysics Data System (ADS)

Barrios, J. M.; Verstraeten, W. W.; Farifteh, J.; Maes, P.; Aerts, J. M.; Coppin, P.

2012-04-01

Lyme borreliosis (LB) is the most common tick-borne disease in Europe and incidence growth has been reported in several European countries during the last decade. LB is caused by the bacterium Borrelia burgdorferi and the main vector of this pathogen in Europe is the tick Ixodes ricinus. LB incidence and spatial spread is greatly dependent on environmental conditions impacting habitat, demography and trophic interactions of ticks and the wide range of organisms ticks parasite. The landscape configuration is also a major determinant of tick habitat conditions and -very important- of the fashion and intensity of human interaction with vegetated areas, i.e. human exposure to the pathogen. Hence, spatial notions as distance and adjacency between urban and vegetated environments are related to human exposure to tick bites and, thus, to risk. This work tested the adequacy of a gravity model setting to model the observed spatio-temporal pattern of LB as a function of location and size of urban and vegetated areas and the seasonal and annual change in the vegetation dynamics as expressed by MODIS NDVI. Opting for this approach implies an analogy with Newton's law of universal gravitation in which the attraction forces between two bodies are directly proportional to the bodies mass and inversely proportional to distance. Similar implementations have proven useful in fields like trade modeling, health care service planning, disease mapping among other. In our implementation, the size of human settlements and vegetated systems and the distance separating these landscape elements are considered the 'bodies'; and the 'attraction' between them is an indicator of exposure to pathogen. A novel element of this implementation is the incorporation of NDVI to account for the seasonal and annual variation in risk. The importance of incorporating this indicator of vegetation activity resides in the fact that alterations of LB incidence pattern observed the last decade have been ascribed to changes in vector habitat induced by a changing climate. Hence, the incorporation of dynamic covariates in epidemiologic modelling schemes is necessary. Preliminary results of this on-going analysis reveal the great potential of this modeling approach to base the incorporation of remotely sensed information of the environment in monitoring shrinkages and expansions of risk zones in this - and probably other - vector-borne disease.

Detection of Rickettsia in Rhipicephalus sanguineus Ticks and Ctenocephalides felis Fleas from Southeastern Tunisia by Reverse Line Blot Assay

PubMed Central

Khrouf, Fatma; M'Ghirbi, Youmna; Znazen, Abir; Ben Jemaa, Mounir; Hammami, Adnene

2014-01-01

Ticks (n = 663) and fleas (n = 470) collected from domestic animals from southeastern Tunisia were screened for Rickettsia infection using reverse line blot assay. Evidence of spotted fever group Rickettsia was obtained. We detected Rickettsia felis in fleas, Rickettsia massiliae Bar 29 and the Rickettsia conorii Israeli spotted fever strain in ticks, and Rickettsia conorii subsp. conorii and Rickettsia spp. in both arthropods. The sensitivity of the adopted technique allowed the identification of a new association between fleas and R. conorii subsp. conorii species. The presence of these vector-borne Rickettsia infections should be considered when diagnosing this disease in humans in Tunisia. PMID:24226919

Identification of Leishmania spp. promastigotes in the intestines, ovaries, and salivary glands of Rhipicephalus sanguineus actively infesting dogs.

PubMed

Viol, Milena Araúz; Guerrero, Felix D; de Oliveira, Bruno César Miranda; de Aquino, Monally Conceição Costa; Loiola, Saulo Hudson; de Melo, Guilherme Dias; de Souza Gomes, Aparecida Helena; Kanamura, Cristina Takami; Garcia, Marcos Valério; Andreotti, Renato; de Lima, Valéria Marçal Félix; Bresciani, Katia Denise Saraiva

2016-09-01

Sand flies are recognized as the major vector of canine visceral leishmaniasis. However, in some areas of Brazil where sand flies do not occur, this disease is found in humans and dogs. There has been speculation that ticks might play a role in transmission of canine visceral leishmaniasis and the DNA of Leishmania spp. has been reported in whole ticks. We investigated the presence of Leishmania spp. promastigotes in the intestines, ovaries, and salivary glands of Rhipicephalus sanguineus ticks collected from tick-infested dogs in two cities of Brazil. We used 66 dogs that tested positive and 33 that tested negative for Leishmania spp. according to direct cytological examination assays. Ten ticks were collected from each dog and dissected to collect the intestines, ovaries, and salivary glands for immunohistochemistry (IHC) and diagnostic real-time polymerase chain reaction (RT-PCR). IHC results showed Leishmania spp. in 98, 14, and 8 % of the intestines, ovaries, and salivary glands, respectively. Real-time PCR showed that 89, 41, and 33 % of the tick intestine, ovary, and salivary glands, respectively, were positive for Leishmania spp. The verification of promastigotes of Leishmania spp. by two independent techniques in ticks collected from these urban region dogs showed that there is need for clarification of the role of ticks in the transmission of canine visceral leishmaniasis in Brazil.

Detection of relapsing fever Borrelia spp., Bartonella spp. and Anaplasmataceae bacteria in argasid ticks in Algeria

PubMed Central

Bitam, Idir; Leulmi, Hamza; Lalout, Reda; Mediannikov, Oleg; Chergui, Mohamed; Karakellah, Mohamed; Raoult, Didier

2017-01-01

Background Argasid ticks (soft ticks) are blood-feeding arthropods that can parasitize rodents, birds, humans, livestock and companion animals. Ticks of the Ornithodoros genus are known to be vectors of relapsing fever borreliosis in humans. In Algeria, little is known about relapsing fever borreliosis and other bacterial pathogens transmitted by argasid ticks. Methodology/Principal findings Between May 2013 and October 2015, we investigated the presence of soft ticks in 20 rodent burrows, 10 yellow-legged gull (Larus michahellis) nests and animal shelters in six locations in two different bioclimatic zones in Algeria. Six species of argasid ticks were identified morphologically and through 16S rRNA gene sequencing. The presence and prevalence of Borrelia spp., Bartonella spp., Rickettsia spp. and Anaplasmataceae was assessed by qPCR template assays in each specimen. All qPCR-positive samples were confirmed by standard PCR, followed by sequencing the amplified fragments. Two Borrelia species were identified: Borrelia hispanica in Ornithodoros occidentalis in Mostaganem, and Borrelia cf. turicatae in Carios capensis in Algiers. One new Bartonella genotype and one new Anaplasmataceae genotype were also identified in Argas persicus. Conclusions The present study highlights the presence of relapsing fever borreliosis agents, although this disease is rarely diagnosed in Algeria. Other bacteria of unknown pathogenicity detected in argasid ticks which may bite humans deserve further investigation. PMID:29145396

Prevalence of Lyme borrelia in Ixodes persulcatus ticks from an area with a confirmed case of Lyme disease.

PubMed

Murase, Yusuke; Konnai, Satoru; Githaka, Naftaly; Hidano, Arata; Taylor, Kyle; Ito, Takuya; Takano, Ai; Ando, Shuji; Kawabata, Hiroki; Tsubota, Toshio; Murata, Shiro; Ohashi, Kazuhiko

2013-02-01

In this study, the prevalence of Borrelia infections in Ixodes ticks from a site in Hokkaido, Japan, with confirmed cases of Lyme disease was determined by a PCR method capable of detecting and differentiating between strains of pathogenic Borrelia, with particular emphasis on Borrelia garinii (B. garinii) and Borrelia afzelli (B. afzelli), using tick-derived DNA extracts as template. A total of 338 ticks, inclusive of 284 Ixodes persulcatus (I. persulcatus), were collected by flagging vegetation in mid-spring. Ninety-eight (34.5%) of I. persulcatus tested positive for Borrelia species DNA, whereas the overall prevalence of Borrelia species in Ixodes ovatus and Haemaphysalis longicornis ticks was 19.5 and 7.7%, respectively. PCR-RFLP and sequence analysis of Borrelia rrf(5S)-rrl(23S) intergenic spacer DNA amplicons indicated that they originated from three different Borrelia species namely, B. garinii, B. afzelii and B. japonica. Among the I. persulcatus species, which is a known vector of human borreliosis, 86 were mono-infected with B. garinii, 2 ticks were mono-infected with B. afzelii and whereas 12 ticks had dual infections. Most significant, 11 of the I. persulcatus ticks were coinfected with Anaplasma phagocytophilum and B. garinii. The difference between the number of obtained and expected co-infections was significant (χ(2)=4.32, P=0.038).

Relationship between habitat type, fire frequency, and Amblyomma americanum populations in east-central Alabama.

PubMed

Willis, Damien; Carter, Robert; Murdock, Chris; Blair, Benjie

2012-12-01

Ticks were collected from 20 sites in the Calhoun, Cherokee, and Cleburne Counties in east-central Alabama areas to determine the relationship between plant physiognomy, environmental variables, and tick populations. Sites investigated included various burning regimes, wildland-urban-interface (WUI), a college campus, and an unmanaged area. Amblyomma americanum (L.) (Acari: Ixodidae) dominated the tick population while Ixodes scapularis Say was not encountered. There were complex differences in tick populations among site conditions. After prescribed burning, the tick population size was small but was larger in subsequent 2- and 5-year post-burn sites. An increase in Odocoileus virginianus foraging in recently burned sites is likely responsible for this phenomenon. WUI areas had the largest tick populations likely due to Odocoileus virginianus activity in an area that provides cover, forage, and a connection to a wildlife refuge. It is possible that the likelihood of humans coming in contact with ticks and tick-borne diseases is greater in WUI areas than in unbroken contiguous forest. A. americanum showed a positive correlation with percent cover of grass and leaf litter mass and a negative relationship with pine sapling density. Variables expected to be strongly correlated with A. americanum populations such as soil moisture, canopy closure, and tree density were found to have weak correlations. © 2012 The Society for Vector Ecology.

Forecasting next season's Ixodes ricinus nymphal density: the example of southern Germany 2018.

PubMed

Brugger, Katharina; Walter, Melanie; Chitimia-Dobler, Lidia; Dobler, Gerhard; Rubel, Franz

2018-05-30

The castor bean tick, Ixodes ricinus (L.) (Ixodida: Ixodidae), is the principal vector of pathogens causing tick-borne encephalitis or Lyme borreliosis in Europe. It is therefore of general interest to make an estimate of the density of I. ricinus for the whole year at the beginning of the tick season. There are two necessary conditions for making a successful prediction: a long homogeneous time series of observed tick density and a clear biological relationship between environmental predictors and tick density. A 9-year time series covering the period 2009-2017 of nymphal I. ricinus flagged at monthly intervals in southern Germany has been used. With the hypothesis that I. ricinus density is triggered by the fructification of the European beech 2 years before, the mean annual temperature of the previous year, and the current mean winter temperature (December-February), a forecast of the annual nymphal tick density has been made. Therefore, a Poisson regression model was generated resulting in an explained variance of 93.4% and an error of [Formula: see text] ticks per [Formula: see text] (annual [Formula: see text] collected ticks/[Formula: see text]). An independent verification of the forecast for the year 2017 resulted in 187 predicted versus 180 observed nymphs per [Formula: see text]. For the year 2018 a relatively high number of 443 questing I. ricinus nymphs per [Formula: see text] is forecasted, i.e., a "good" tick year.

Francisella tularensis: No Evidence for Transovarial Transmission in the Tularemia Tick Vectors Dermacentor reticulatus and Ixodes ricinus.

PubMed

Genchi, Marco; Prati, Paola; Vicari, Nadia; Manfredini, Andrea; Sacchi, Luciano; Clementi, Emanuela; Bandi, Claudio; Epis, Sara; Fabbi, Massimo

2015-01-01

Tularemia is a zoonosis caused by the Francisella tularensis, a highly infectious Gram-negative coccobacillus. Due to easy dissemination, multiple routes of infection, high environmental contamination and morbidity and mortality rates, Francisella is considered a potential bioterrorism threat and classified as a category A select agent by the CDC. Tick bites are among the most prevalent modes of transmission, and ticks have been indicated as a possible reservoir, although their reservoir competence has yet to be defined. Tick-borne transmission of F. tularensis was recognized in 1923, and transstadial transmission has been demonstrated in several tick species. Studies on transovarial transmission, however, have reported conflicting results. The aim of this study was to evaluate the role of ticks as reservoirs for Francisella, assessing the transovarial transmission of F. tularensis subsp. holarctica in ticks, using experimentally-infected females of Dermacentor reticulatus and Ixodes ricinus. Transmission electron microscopy and fluorescence in situ hybridization showed F. tularensis within oocytes. However, cultures and bioassays of eggs and larvae were negative; in addition, microscopy techniques revealed bacterial degeneration/death in the oocytes. These results suggest that bacterial death might occur in oocytes, preventing the transovarial transmission of Francisella. We can speculate that Francisella does not have a defined reservoir, but that rather various biological niches (e.g. ticks, rodents), that allow the bacterium to persist in the environment. Our results, suggesting that ticks are not competent for the bacterium vertical transmission, are congruent with this view.

A Geographical Information System Based Approach for Integrated Strategies of Tick Surveillance and Control in the Peri-Urban Natural Reserve of Monte Pellegrino (Palermo, Southern Italy)

PubMed Central

Torina, Alessandra; Blanda, Marcellocalogero; Auteri, Michelangelo; La Russa, Francesco; Scimeca, Salvatore; D’Agostino, Rosalia; Disclafani, Rosaria; Currò, Vittoria; Caracappa, Santo

2018-01-01

Ticks (Acari: Ixodidae) are bloodsucking arthropods involved in pathogen transmission in animals and humans. Tick activity depends on various ecological factors such as vegetation, hosts, and temperature. The aim of this study was to analyse the spatial/temporal distribution of ticks in six sites within a peri-urban area of Palermo (Natural Reserve of Monte Pellegrino) and correlate it with field data using Geographical Information System (GIS) data. A total of 3092 ticks were gathered via dragging method from June 2012 to May 2014. The species collected were: Ixodes ventalloi (46.09%), Hyalomma lusitanicum (19.99%), Rhipicephalus sanguineus (17.34%), Rhipicephalus pusillus (16.11%), Haemaphisalis sulcata (0.36%), Dermacentor marginatus (0.10%), and Rhipicephalus turanicus (0.03%). GIS analysis revealed environmental characteristics of each site, and abundance of each tick species was analysed in relation to time (monthly trend) and space (site-specific abundance). A relevant presence of I. ventalloi in site 2 and H. lusitanicum in site 5 was observed, suggesting the possible exposure of animals and humans to tick-borne pathogens. Our study shows the importance of surveillance of ticks in peri-urban areas and the useful implementation of GIS analysis in vector ecology; studies on temporal and spatial distribution of ticks correlated to GIS-based ecological analysis represent an integrated strategy for decision support in public health. PMID:29495440

Molecular survey of neglected bacterial pathogens reveals an abundant diversity of species and genotypes in ticks collected from animal hosts across Romania.

PubMed

Andersson, Martin O; Tolf, Conny; Tamba, Paula; Stefanache, Mircea; Radbea, Gabriel; Frangoulidis, Dimitrios; Tomaso, Herbert; Waldenström, Jonas; Dobler, Gerhard; Chitimia-Dobler, Lidia

2018-03-20

Ticks are transmitting a wide range of bacterial pathogens that cause substantial morbidity and mortality in domestic animals. The full pathogen burden transmitted by tick vectors is incompletely studied in many geographical areas, and extensive studies are required to fully understand the diversity and distribution of pathogens transmitted by ticks. We sampled 824 ticks of 11 species collected in 19 counties in Romania. Ticks were collected mainly from dogs, but also from other domestic and wild animals, and were subjected to molecular screening for pathogens. Rickettsia spp. was the most commonly detected pathogen, occurring in 10.6% (87/824) of ticks. Several species were detected: Rickettsia helvetica, R. raoultii, R. massiliae, R. monacensis, R. slovaca and R. aeschlimannii. A single occurrence of the zoonotic bacterium Bartonella vinsonii berkhoffii was detected in a tick collected from a dog. Anaplasma phagocytophilum occurred in four samples, and sequences similar to Anaplasma marginale/ovis were abundant in ticks from ruminants. In addition, molecular screening showed that ticks from dogs were carrying an Ehrlichia species identical to the HF strain as well as the enigmatic zoonotic pathogen "Candidatus Neoehrlichia mikurensis". An organism similar to E. chaffeensis or E. muris was detected in an Ixodes ricinus collected from a fox. We describe an abundant diversity of bacterial tick-borne pathogens in ticks collected from animal hosts in Romania, both on the level of species and genotypes/strains within these species. Several findings were novel for Romania, including Bartonella vinsonii subsp. berkhoffii that causes bacteremia and endocarditis in dogs. "Candidatus Neoehrlichia mikurensis" was detected in a tick collected from a dog. Previously, a single case of infection in a dog was diagnosed in Germany. The results warrant further studies on the consequences of tick-borne pathogens in domestic animals in Romania.

Immune Cell Targets of Infection at the Tick-Skin Interface during Powassan Virus Transmission

PubMed Central

Hermance, Meghan E.; Santos, Rodrigo I.; Kelly, Brent C.; Valbuena, Gustavo; Thangamani, Saravanan

2016-01-01

Powassan virus (POWV) is a tick-borne flavivirus that can result in a severe neuroinvasive disease with 50% of survivors displaying long-term neurological sequelae. Human POWV cases have been documented in Canada, the United States, and Russia. Although the number of reported POWV human cases has increased in the past fifteen years, POWV remains one of the less studied human pathogenic flaviviruses. Ixodes ticks are the vectors for POWV, and the virus is transmitted to a host’s skin very early during the tick feeding process. Central to the successful transmission of a tick-borne pathogen are complex interactions between the host immune response and early tick-mediated immunomodulation, all of which initially occur at the skin interface. In our prior work, we examined the cutaneous immune gene expression during the early stages of POWV-infected Ixodes scapularis feeding. The present study serves to further investigate the skin interface by identifying early cell targets of infection at the POWV-infected tick feeding site. An in vivo infection model consisting of POWV-infected ticks feeding on mice for short durations was used in this study. Skin biopsies from the tick feeding sites were harvested at various early time points, enabling us to examine the skin histopathology and detect POWV viral antigen in immune cells present at the tick feeding site. The histopathology from the present study demonstrates that neutrophil and mononuclear cell infiltrates are recruited earlier to the feeding site of a POWV-infected tick versus an uninfected tick. This is the first report demonstrating that macrophages and fibroblasts contain POWV antigens, which suggests that they are early cellular targets of infection at the tick feeding site. These data provide key insights towards defining the complex interactions between the host immune response and early tick-mediated immunomodulation. PMID:27203436

Prevalence of severe fever with thrombocytopenia syndrome virus in Haemaphysalis longicornis ticks in South Korea.

PubMed

Park, Sun-Whan; Song, Bong Gu; Shin, E-Hyun; Yun, Seok-Min; Han, Myung-Guk; Park, Mi Yeoun; Park, Chan; Ryou, Jungsang

2014-10-01

Haemaphysalis longicornis a vector that harbors severe fever with thrombocytopenia syndrome virus (SFTSV) is a major species of tick in South Korea. To investigate the existence and prevalence of SFTSV in Korea, we collected ticks from nine provinces in South Korea for detecting SFTSV. In all, we collected 13,053 ticks, and H. longicornis (90.8%, 11,856/13,053) was the most abundant among them. The minimum infection rate (MIR) of SFTSV in H. longicornis was 0.46% (55 pools). SFTSV was detected in ticks during all the developmental stages, showing MIR in larvae (2/350, 0.57%), nymphs (38/10,436, 0.36%), males (2/221, 0.90%), and females (13/849, 1.53%), respectively. Viruses were detected in ticks collected between April and September. A higher MIR was detected in ticks from the southern part of the country. We amplified the M and S segment partial genes from a sample and analyzed the nucleotide sequence. The results showed a 93-98% homology to Chinese and Japanese strains registered in Genbank. In this study, we confirmed the existence of SFTSV for the first time in South Korea. The SFTSV prevalence data from the studies are essential for raising the awareness of SFTS in South Korea. Copyright © 2014 Elsevier GmbH. All rights reserved.

Exploring the immune signalling pathway-related genes of the cattle tick Rhipicephalus microplus: From molecular characterization to transcriptional profile upon microbial challenge.

PubMed

Rosa, Rafael D; Capelli-Peixoto, Janaína; Mesquita, Rafael D; Kalil, Sandra P; Pohl, Paula C; Braz, Glória R; Fogaça, Andrea C; Daffre, Sirlei

2016-06-01

In dipteran insects, invading pathogens are selectively recognized by four major pathways, namely Toll, IMD, JNK, and JAK/STAT, and trigger the activation of several immune effectors. Although substantial advances have been made in understanding the immunity of model insects such as Drosophila melanogaster, knowledge on the activation of immune responses in other arthropods such as ticks remains limited. Herein, we have deepened our understanding of the intracellular signalling pathways likely to be involved in tick immunity by combining a large-scale in silico approach with high-throughput gene expression analysis. Data from in silico analysis revealed that although both the Toll and JAK/STAT signalling pathways are evolutionarily conserved across arthropods, ticks lack central components of the D. melanogaster IMD pathway. Moreover, we show that tick immune signalling-associated genes are constitutively transcribed in BME26 cells (a cell lineage derived from embryos of the cattle tick Rhipicephalus microplus) and exhibit different transcriptional patterns in response to microbial challenge. Interestingly, Anaplasma marginale, a pathogen that is naturally transmitted by R. microplus, causes downregulation of immune-related genes, suggesting that this pathogen may manipulate the tick immune system, favouring its survival and vector colonization. Copyright © 2015 Elsevier Ltd. All rights reserved.

Presence of Borrelia spp. DNA in ticks, but absence of Borrelia spp. and of Leptospira spp. DNA in blood of fever patients in Madagascar.

PubMed

Hagen, Ralf Matthias; Frickmann, Hagen; Ehlers, Julian; Krüger, Andreas; Margos, Gabriele; Hizo-Teufel, Cecilia; Fingerle, Volker; Rakotozandrindrainy, Raphael; Kalckreuth, Vera von; Im, Justin; Pak, Gi Deok; Jeon, Hyon Jin; Rakotondrainiarivelo, Jean Philibert; Heriniaina, Jean Noël; Razafindrabe, Tsiry; Konings, Frank; May, Jürgen; Hogan, Benedikt; Ganzhorn, Jörg; Panzner, Ursula; Schwarz, Norbert Georg; Dekker, Denise; Marks, Florian; Poppert, Sven

2018-01-01

The occurrence of tick-borne relapsing fever and leptospirosis in humans in Madagascar remains unclear despite the presence of their potential vectors and reservoir hosts. We screened 255 Amblyomma variegatum ticks and 148 Rhipicephalus microplus ticks from Zebu cattle in Madagascar for Borrelia-specific DNA. Borrelia spp. DNA was detected in 21 Amblyomma variegatum ticks and 2 Rhipicephalus microplus ticks. One Borrelia found in one Rhipicephalus microplus showed close relationship to Borrelia theileri based on genetic distance and phylogenetic analyses on 16S rRNA and flaB sequences. The borreliae from Amblyomma variegatum could not be identified due to very low quantities of present DNA reflected by high cycle threshold values in real-time-PCR. It is uncertain whether these low numbers of Borrelia spp. are sufficient for transmission of infection from ticks to humans. In order to determine whether spirochaete infections are relevant in humans, blood samples of 1009 patients from the highlands of Madagascar with fever of unknown origin were screened for Borrelia spp. - and in addition for Leptospira spp. - by real-time PCR. No target DNA was detected, indicating a limited relevance of these pathogens for humans in the highlands of Madagascar. Copyright © 2017 Elsevier B.V. All rights reserved.

Modelling the seasonality of Lyme disease risk and the potential impacts of a warming climate within the heterogeneous landscapes of Scotland.

PubMed

Li, Sen; Gilbert, Lucy; Harrison, Paula A; Rounsevell, Mark D A

2016-03-01

Lyme disease is the most prevalent vector-borne disease in the temperate Northern Hemisphere. The abundance of infected nymphal ticks is commonly used as a Lyme disease risk indicator. Temperature can influence the dynamics of disease by shaping the activity and development of ticks and, hence, altering the contact pattern and pathogen transmission between ticks and their host animals. A mechanistic, agent-based model was developed to study the temperature-driven seasonality of Ixodes ricinus ticks and transmission of Borrelia burgdorferi sensu lato across mainland Scotland. Based on 12-year averaged temperature surfaces, our model predicted that Lyme disease risk currently peaks in autumn, approximately six weeks after the temperature peak. The risk was predicted to decrease with increasing altitude. Increases in temperature were predicted to prolong the duration of the tick questing season and expand the risk area to higher altitudinal and latitudinal regions. These predicted impacts on tick population ecology may be expected to lead to greater tick-host contacts under climate warming and, hence, greater risks of pathogen transmission. The model is useful in improving understanding of the spatial determinants and system mechanisms of Lyme disease pathogen transmission and its sensitivity to temperature changes. © 2016 The Author(s).

Transstadial Transmission and Long-term Association of Crimean-Congo Hemorrhagic Fever Virus in Ticks Shapes Genome Plasticity

PubMed Central

Xia, Han; Beck, Andrew S.; Gargili, Aysen; Forrester, Naomi; Barrett, Alan D. T.; Bente, Dennis A.

2016-01-01

The trade-off hypothesis, the current paradigm of arbovirus evolution, proposes that cycling between vertebrate and invertebrate hosts presents significant constraints on genetic change of arboviruses. Studying these constraints in mosquito-borne viruses has led to a new understanding of epizootics. The trade-off hypothesis is assumed to be applicable to tick-borne viruses too, although studies are lacking. Tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the family Bunyaviridae, is a major cause of severe human disease worldwide and shows an extraordinary amount of genetic diversity compared to other arboviruses, which has been linked to increased virulence and emergence in new environments. Using a transmission model for CCHFV, utilizing the main vector tick species and mice plus next generation sequencing, we detected a substantial number of consensus-level mutations in CCHFV recovered from ticks after only a single transstadial transmission, whereas none were detected in CCHFV obtained from the mammalian host. Furthermore, greater viral intra-host diversity was detected in the tick compared to the vertebrate host. Long-term association of CCHFV with its tick host for 1 year demonstrated mutations in the viral genome become fixed over time. These findings suggest that the trade-off hypothesis may not be accurate for all arboviruses. PMID:27775001

Transstadial Transmission and Long-term Association of Crimean-Congo Hemorrhagic Fever Virus in Ticks Shapes Genome Plasticity.

PubMed

Xia, Han; Beck, Andrew S; Gargili, Aysen; Forrester, Naomi; Barrett, Alan D T; Bente, Dennis A

2016-10-24

The trade-off hypothesis, the current paradigm of arbovirus evolution, proposes that cycling between vertebrate and invertebrate hosts presents significant constraints on genetic change of arboviruses. Studying these constraints in mosquito-borne viruses has led to a new understanding of epizootics. The trade-off hypothesis is assumed to be applicable to tick-borne viruses too, although studies are lacking. Tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the family Bunyaviridae, is a major cause of severe human disease worldwide and shows an extraordinary amount of genetic diversity compared to other arboviruses, which has been linked to increased virulence and emergence in new environments. Using a transmission model for CCHFV, utilizing the main vector tick species and mice plus next generation sequencing, we detected a substantial number of consensus-level mutations in CCHFV recovered from ticks after only a single transstadial transmission, whereas none were detected in CCHFV obtained from the mammalian host. Furthermore, greater viral intra-host diversity was detected in the tick compared to the vertebrate host. Long-term association of CCHFV with its tick host for 1 year demonstrated mutations in the viral genome become fixed over time. These findings suggest that the trade-off hypothesis may not be accurate for all arboviruses.

Molecular epidemiology of bovine anaplasmosis with a particular focus in Mexico.

PubMed

Rodríguez, Sergio D; García Ortiz, Miguel Angel; Jiménez Ocampo, Rafael; Vega y Murguía, Carlos A

2009-12-01

Bovine anaplasmosis, caused by the rickettsia Anaplasma marginale, has a worldwide distribution and is the cause of great economic losses in developing countries where it is highly endemic. Transmission is carried mainly by ixodid ticks: Dermacentor spp. and Rhipicephalus (Boophilus) spp. Mechanical transmission is important in disseminating the disease within and across herds. The relationship between the rickettsia, the host and the vector is complex. Several surface proteins (Msps) have been described with functions that span from adhesins towards the erythrocyte and tick cells to evasion of the immune system of the host through the generation of antigenic variants. Biologic transmission of A. marginale through Dermacentor ticks has been well studied but many questions are unresolved as to how this organism spreads within and across herds and little is known about the role Rhipicephalus (Boophilus) ticks play in transmission in the Americas. Mechanical transmission in the absence of ticks and lack of transmission through ticks are questions that need to be addressed. Phylogenetic studies of the rickettsia show wide antigenic and genetic mosaics which affects the design of new vaccines. In the present work we will discuss the molecular elements in the relationship between the rickettsia, the tick and the mammalian host associated to the distribution and persistence of the pathogen in nature.

Facilitative ecological interactions between invasive species: Arundo donax stands as favorable habitat for cattle ticks (Acari: Ixodidae) along the U.S.-Mexico border.

PubMed

Racelis, A E; Davey, R B; Goolsby, J A; Pérez de León, A A; Varner, K; Duhaime, R

2012-03-01

The cattle tick, Rhipicephalus (Boophilus) spp. is a key vector of protozoa that cause bovine babesiosis. Largely eradicated from most of the United States, the cattle tick continues to infest south Texas, and recent outbreaks in this area may signal a resurgence of cattle tick populations despite current management efforts. An improved understanding of the dynamic ecology of cattle fever ticks along the U.S.-Mexico border is required to devise strategies for sustainable eradication efforts. Management areas of the cattle tick overlap considerably with dense, wide infestations of the non-native, invasive grass known as giant reed (Arundo donax L.). Here we show that stands of giant reed are associated with abiotic and biotic conditions that are favorable to tick survival, especially when compared with other nearby habitats (open pastures of buffelgrass (Pennisetum ciliare) and closed canopy native forests). Overhead canopies in giant reed stands and native riparian forests reduce daily high temperature, which was the best abiotic predictor of oviposition by engorged females. In sites where temperatures were extreme, specifically open grasslands, fewer females laid eggs and the resulting egg masses were smaller. Pitfall trap collections of ground dwelling arthropods suggest a low potential for natural suppression of tick populations in giant reed stands. The finding that A. donax infestations present environmental conditions that facilitate the survival and persistence of cattle ticks, as well or better than native riparian habitats and open grasslands, represents an alarming complication for cattle fever tick management in the United States.

The embryogenesis of the tick Rhipicephalus (Boophilus) microplus: the establishment of a new chelicerate model system.

PubMed

Santos, Vitória Tobias; Ribeiro, Lupis; Fraga, Amanda; de Barros, Cíntia Monteiro; Campos, Eldo; Moraes, Jorge; Fontenele, Marcio Ribeiro; Araújo, Helena Marcolla; Feitosa, Natalia Martins; Logullo, Carlos; da Fonseca, Rodrigo Nunes

2013-12-01

Chelicerates, which include spiders, ticks, mites, scorpions, and horseshoe crabs, are members of the phylum Arthropoda. In recent years, several molecular experimental studies of chelicerates have examined the embryology of spiders; however, the embryology of other groups, such as ticks (Acari: Parasitiformes), has been largely neglected. Ticks and mites are believed to constitute a monophyletic group, the Acari. Due to their blood-sucking activities, ticks are also known to be vectors of several diseases. In this study, we analyzed the embryonic development of the cattle tick, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). First, we developed an embryonic staging system consisting of 14 embryonic stages. Second, histological analysis and antibody staining unexpectedly revealed the presence of a population of tick cells with similar characteristics to the spider cumulus. Cumulus cell populations also exist in other chelicerates; these cells are responsible for the breaking of radial symmetry through bone morphogenetic protein signaling. Third, it was determined that the posterior (opisthosomal) embryonic region of R. microplus is segmented. Finally, we identified the presence of a transient ventral midline furrow and the formation and regression of a fourth leg pair; these features may be regarded as hallmarks of late tick embryogenesis. Importantly, most of the aforementioned features are absent from mite embryos, suggesting that mites and ticks do not constitute a monophyletic group or that mites have lost these features. Taken together, our findings provide fundamental common ground for improving knowledge regarding tick embryonic development, thereby facilitating the establishment of a new chelicerate model system. Copyright © 2013 Wiley Periodicals, Inc.

Identification of a follistatin-related protein from the tick Haemaphysalis longicornis and its effect on tick oviposition.

PubMed

Zhou, Jinlin; Liao, Min; Hatta, Takeshi; Tanaka, Miho; Xuan, Xuenan; Fujisaki, Kozo

2006-05-10

The identification of ovary-associated molecules will lead to a better understanding of the physiology of tick reproduction and vector-pathogen interactions. A gene encoding a follistatin-related protein (FRP) was obtained by random sequencing from the ovary cDNA library of the tick Haemaphysalis longicornis. The full-length cDNA is 1157 bp, including an intact ORF encoding an expected protein with 289 amino acids. Three distinct domains were present in the deduced amino acids, namely, the follistatin-like domain, KAZAL, and two calcium-binding motifs, EFh. The sequence shows homology with the follistatin-related protein (FRP), which was thought to play some roles in the negative regulation of cellular growth. RT-PCR showed that the gene was expressed throughout the developing stages and mainly in the ovary as well as in fat body, hemocytes, salivary glands, and midgut. This gene was expressed in GST-fused recombinant protein with an expected size. The mouse antiserum against the recombinant protein recognized a 56-kDa native protein in both tick ovary and hemolymph. The recombinant proteins were found to have binding activity for both activin A and bone morphogenetic protein-2 (BMP-2). Silencing of FRP by RNAi showed a decrease in tick oviposition, which is consistent with the effect of a recombinant protein vaccine on the adult tick. These results showed that the tick FRP might be involved in tick oviposition. This is the first report of a member of follistatin family proteins in Chelicerata, which include ticks, spiders, and scorpions.

Mutation in the Sodium Channel Gene Corresponds With Phenotypic Resistance of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) to Pyrethroids.

PubMed

Klafke, G M; Miller, R J; Tidwell, J; Barreto, R; Guerrero, F D; Kaufman, P E; Pérez de León, A A

2017-11-07

The brown dog tick, Rhipicephalus sanguineus sensu lato (Latreille), is a cosmopolitan ectoparasite and vector of pathogens that kill humans and animals. Pyrethroids represent a class of synthetic acaricides that have been used intensely to try to control the brown dog tick and mitigate the risk of tick-borne disease transmission. However, acaricide resistance is an emerging problem in the management of the brown dog tick. Understanding the mechanism of resistance to acaricides, including pyrethroids, is important to adapt brown dog tick control strategies. The main objective of this study was to determine if target-site mutations associated with pyrethroid resistance in other pests could be associated with phenotypic resistance detected in a brown dog tick population from Florida. We amplified segment 6 of the domain III of the voltage-sensitive sodium channel protein, using cDNAs synthesized from pyrethroid-susceptible and pyrethroid-resistant tick strains. A single nucleotide point mutation (SNP) identified in a highly conserved region of domain III S6 in the resistant ticks resulted in an amino acid change from phenylalanine to leucine. This mutation is characteristic of resistance phenotypes in other tick species, and is the first report of this mutation in R. sanguineus. Molecular assays based on this knowledge could be developed to diagnose the risk for pyrethroid resistance, and to inform decisions on integrated brown dog tick management practices. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The natural infection of birds and ticks feeding on birds with Rickettsia spp. and Coxiella burnetii in Slovakia.

PubMed

Berthová, Lenka; Slobodník, Vladimír; Slobodník, Roman; Olekšák, Milan; Sekeyová, Zuzana; Svitálková, Zuzana; Kazimírová, Mária; Špitalská, Eva

2016-03-01

Ixodid ticks (Acari: Ixodidae) are known as primary vectors of many pathogens causing diseases in humans and animals. Ixodes ricinus is a common ectoparasite in Europe and birds are often hosts of subadult stages of the tick. From 2012 to 2013, 347 birds belonging to 43 species were caught and examined for ticks in three sites of Slovakia. Ticks and blood samples from birds were analysed individually for the presence of Rickettsia spp. and Coxiella burnetii by PCR-based methods. Only I. ricinus was found to infest birds. In total 594 specimens of bird-attached ticks were collected (451 larvae, 142 nymphs, 1 female). Altogether 37.2% (16/43) of bird species were infested by ticks and some birds carried more than one tick. The great tit, Parus major (83.8%, 31/37) was the most infested species. In total, 6.6 and 2.7% of bird-attached ticks were infected with Rickettsia spp. and C. burnetii, respectively. Rickettsia helvetica predominated (5.9%), whereas R. monacensis (0.5%) was only sporadically detected. Coxiella burnetii was detected in 0.9%, Rickettsia spp. in 8.9% and R. helvetica in 4.2% of bird blood samples. The great tit was the bird species most infested with I. ricinus, carried R. helvetica and C. burnetti positive tick larvae and nymphs and was found to be rickettsaemic in its blood. Further studies are necessary to define the role of birds in the circulation of rickettsiae and C. burnetii in natural foci.

Molecular Detection of Tick-Borne Pathogens in Humans with Tick Bites and Erythema Migrans, in the Netherlands

PubMed Central

Jahfari, Setareh; Hofhuis, Agnetha; Fonville, Manoj; van der Giessen, Joke; van Pelt, Wilfrid; Sprong, Hein

2016-01-01

Background Tick-borne diseases are the most prevalent vector-borne diseases in Europe. Knowledge on the incidence and clinical presentation of other tick-borne diseases than Lyme borreliosis and tick-borne encephalitis is minimal, despite the high human exposure to these pathogens through tick bites. Using molecular detection techniques, the frequency of tick-borne infections after exposure through tick bites was estimated. Methods Ticks, blood samples and questionnaires on health status were collected from patients that visited their general practitioner with a tick bite or erythema migrans in 2007 and 2008. The presence of several tick-borne pathogens in 314 ticks and 626 blood samples of this cohort were analyzed using PCR-based methods. Using multivariate logistic regression, associations were explored between pathogens detected in blood and self-reported symptoms at enrolment and during a three-month follow-up period. Results Half of the ticks removed from humans tested positive for Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, Rickettsia helvetica, Rickettsia monacensis, Borrelia miyamotoi and several Babesia species. Among 92 Borrelia burgdorferi s. l. positive ticks, 33% carried another pathogen from a different genus. In blood of sixteen out of 626 persons with tick bites or erythema migrans, DNA was detected from Candidatus Neoehrlichia mikurensis (n = 7), Anaplasma phagocytophilum (n = 5), Babesia divergens (n = 3), Borrelia miyamotoi (n = 1) and Borrelia burgdorferi s. l. (n = 1). None of these sixteen individuals reported any overt symptoms that would indicate a corresponding illness during the three-month follow-up period. No associations were found between the presence of pathogen DNA in blood and; self-reported symptoms, with pathogen DNA in the corresponding ticks (n = 8), reported tick attachment duration, tick engorgement, or antibiotic treatment at enrolment. Conclusions Based on molecular detection techniques, the probability of infection with a tick-borne pathogen other than Lyme spirochetes after a tick bite is roughly 2.4%, in the Netherlands. Similarly, among patients with erythema migrans, the probability of a co-infection with another tick-borne pathogen is approximately 2.7%. How often these infections cause disease symptoms or to what extend co-infections affect the course of Lyme borreliosis needs further investigations. PMID:27706159

Nested coevolutionary networks shape the ecological relationships of ticks, hosts, and the Lyme disease bacteria of the Borrelia burgdorferi (s.l.) complex.

PubMed

Estrada-Peña, Agustín; Sprong, Hein; Cabezas-Cruz, Alejandro; de la Fuente, José; Ramo, Ana; Coipan, Elena Claudia

2016-09-23

The bacteria of the Borrelia burgdorferi (s.l.) (BBG) complex constitute a group of tick-transmitted pathogens that are linked to many vertebrate and tick species. The ecological relationships between the pathogens, the ticks and the vertebrate carriers have not been analysed. The aim of this study was to quantitatively analyse these interactions by creating a network based on a large dataset of associations. Specifically, we examined the relative positions of partners in the network, the phylogenetic diversity of the tick's hosts and its impact on BBG circulation. The secondary aim was to evaluate the segregation of BBG strains in different vectors and reservoirs. BBG circulates through a nested recursive network of ticks and vertebrates that delineate closed clusters. Each cluster contains generalist ticks with high values of centrality as well as specialist ticks that originate nested sub-networks and that link secondary vertebrates to the cluster. These results highlighted the importance of host phylogenetic diversity for ticks in the circulation of BBG, as this diversity was correlated with high centrality values for the ticks. The ticks and BBG species in each cluster were not significantly associated with specific branches of the phylogeny of host genera (R 2  = 0.156, P = 0.784 for BBG; R 2  = 0.299, P = 0.699 for ticks). A few host genera had higher centrality values and thus higher importance for BBG circulation. However, the combined contribution of hosts with low centrality values could maintain active BBG foci. The results suggested that ticks do not share strains of BBG, which were highly segregated among sympatric species of ticks. We conclude that BBG circulation is supported by a highly redundant network. This network includes ticks with high centrality values and high host phylogenetic diversity as well as ticks with low centrality values. This promotes ecological sub-networks and reflects the high resilience of BBG circulation. The functional redundancy in BBG circulation reduces disturbances due to the removal of vertebrates as it allows ticks to fill other biotic niches.

Major vectors and vector-borne diseases in small ruminants in Ethiopia: A systematic review.

PubMed

Asmare, Kassahun; Abayneh, Takele; Sibhat, Berhanu; Shiferaw, Dessie; Szonyi, Barbara; Krontveit, Randi I; Skjerve, Eystein; Wieland, Barbara

2017-06-01

Vector-borne diseases are among major health constraints of small ruminant in Ethiopia. While various studies on single vector-borne diseases or presence of vectors have been conducted, no summarized evidence is available on the occurrence of these diseases and the related vectors. This systematic literature review provides a comprehensive summary on major vectors and vector-borne diseases in small ruminants in Ethiopia. Search for published and unpublished literature was conducted between 8th of January and 25th of June 2015. The search was both manual and electronic. The databases used in electronic search were PubMed, Web of Science, CAB Direct and AJOL. For most of the vector-borne diseases, the summary was limited to narrative synthesis due to lack of sufficient data. Meta-analysis was computed for trypanosomosis and dermatophilosis while meta-regression and sensitivity analysis was done only for trypanososmosis due to lack of sufficient reports on dermatophilosis. Owing emphasis to their vector role, ticks and flies were summarized narratively at genera/species level. In line with inclusion criteria, out of 106 initially identified research reports 43 peer-reviewed articles passed the quality assessment. Data on 7 vector-borne diseases were extracted at species and region level from each source. Accordingly, the pooled prevalence estimate of trypanosomosis was 3.7% with 95% confidence interval (CI) 2.8, 4.9), while that of dermatophilosis was 3.1% (95% CI: 1.6, 6.0). The in-between study variance noted for trypanosomosis was statistically significant (p<0.05). Among the three covariates considered for meta-regression, only one (species) fitted the final model significantly (p<0.05) and explained 65.44% of the between studies variance (R 2 ). The prevalence in sheep (5.5%) increased nearly by 34% compared to goats (2.9%). The parasitic presence in blood was documented for babesiosis (3.7% in goats); and anaplasmosis (3.9% in sheep). Serological evidence was retrieved for bluetongue ranging from 34.1% to 46.67% in sheep, and coxiellosis was 10.4% in goats. There was also molecular evidence on the presence of theileriosis in sheep (93%, n=160) and goats (1.9%, n=265). Regarding vectors of veterinary importance, 14 species of ticks in five genera, four species of Glossina and 4 genera of biting flies were reported. Despite the evidence on presence of various vectors including ticks, flies, mosquitoes and midges, studies on vector-borne diseases in Ethiopia are surprisingly rare, especially considering risks related to climate change, which is likely to affect distribution of vectors. Thus better evidence on the current situation is urgently needed in order to prevent spread and to model future distribution scenarios. Copyright © 2017 Elsevier B.V. All rights reserved.