Allan, Brian F
The increasingly widespread use of prescribed burns to manage oak (Quercus spp.)-hickory (Carya spp.) forests in the Missouri Ozarks, USA, has considerable potential to alter the abundance of Amblyomma americanum (L.) (Acari: Ixodidae), the lone star tick, an important vector of several emerging pathogens. In particular, responses of important tick hosts, primarily white-tailed deer (Odocoileus virginianus), to fire management and the resultant changes in the distribution and abundance of A. americanum are largely unknown. Using several large burn units (61-242 ha) within the Ozark ecosystem, I measured the effect of the time elapsed since sites were burned on the density of white-tailed deer and the larval life stage of A. americanum. Larval tick densities were highest in areas that were 2 yr postburn and were > 6 times higher than tick densities in control units. Deer densities were highest in sites that were burned in the same year as this study and decreased significantly with time since burn. These results suggest that intensive use of postburn sites by white-tailed deer may increase the abundance of A. americanum to levels greater than occurs in sites that remain unburned. Thus, fire management, although beneficial in many aspects of ecosystem management, may bear the unintended cost of locally increasing abundance of A. americanum.
Ewing, S A; Mathew, J S; Panciera, R J
American canine hepatozoonosis (ACH) caused by Hepatozoon americanum Vincent-Johnson, Macintire, Lindsay, Lenz, Baneth, and Shkap is an emerging, often fatal, tick-borne protozoal disease of dogs in the United States of America. Dogs acquire infection by ingesting ticks that contain oocysts. To understand the invertebrate (definitive) host range of H. americanum, experiments were carried out using four ixodids, Rhipicephalus sanguineus (Latreille), Dermacentor variabilis Say, Amblyomma americanum (L.), and Amblyomma maculatum Koch. Laboratory-reared nymphal ticks were fed on dogs that were either naturally or experimentally infected with H. americanum; when these ticks molted to the adult stage they were either fed to susceptible dogs or were dissected and examined for the presence of oocysts. Mature H. americanum oocysts were found in >90% of A. maculatum (both males and females), whereas oocysts were not found in any of the other three species. These results confirm that A. maculatum is an excellent host and vector for H. americanum and also suggest that this apicomplexan may have a narrow invertebrate host range, at least among ixodid ticks that are likely candidate vectors in the United States.
Lohmeyer, K H; Miller, J A; Pound, J M; Oehler, D D
Steers were treated with doramectin or eprinomectin by daily oral capsule for 28 consecutive days. The level of doramectin in the serum of steers treated at 200 microg/kg/d reached a maximum of 104.0 +/- 22.1 ppb at day 21 and declined from 93.3 +/- 20.5 ppb on the final day of treatment to below detectable by day 56. Steers treated at 50 microg/kg/d reached a maximum level of doramectin in the serum of 24.7 +/- 1.2 ppb on day 21 and declined from 24.7 +/- 0.6 ppb on the final day of treatment to less than detectable on day 42. Both doramectin dosages provided 100% control of estimated larvae (EL) of Amblyomma americanum (L.) (Acari: Ixodidae) throughout the 28-d treatment period. Daily oral treatment with eprinomectin at a dosage of 200 microg/kg for 28 consecutive days produced a maximum concentration in the serum of 41.6 +/- 11.0 ppb at day 14. On the final day of eprinomectin treatment, the serum concentration was 38.3 +/- 5.9 ppb. Seven days later at day 35, eprinomectin was not detectable in the serum. For steers treated at 50 microg/kg/d for 28 consecutive days, the serum level of eprinomectin reached a maximum of 10.0 +/- 3.0 ppb on day 28 and was undetectable on day 35. Both eprinomectin dosages provided complete control of EL of A. americanum during the 28-d treatment period. Because eprinomectin is efficacious against A. americanum at lower serum levels in cattle and is eliminated from the serum at a more rapid rate than either doramectin or ivermectin, it provides advantages for use in applications such as the medicated bait for control of ticks on white-tailed deer and could have potential for use in the Cattle Fever Tick Eradication Program.
Heise, Stephanie R; Elshahed, M S; Little, S E
The lone star tick, Amblyomma americanum (Acari: Ixodidae), is commonly reported from people and animals throughout the eastern U.S. and is associated with transmission of a number of emerging diseases. To better define the microbial communities within lone star ticks, 16S rRNA gene based analysis using bacteria-wide primers, followed by sequencing of individual clones (n = 449) was used to identify the most common bacterial operational taxonomic units (OTUs) present within colony-reared and wild A. americanum. The colony-reared ticks contained primarily sequence affiliated with members of the genus Coxiella (89%; 81/91), common endosymbionts of ticks, and Brevibacterium (11%; 10/91). Similarly, analysis of clones from unfed wild lone star ticks revealed that 96.7% (89/92) of all the OTUs identified were affiliated with Coxiella-like endosymbionts, as compared with only 5.1-11.7% (5/98-9/77) of those identified from wild lone star ticks after feeding. In contrast, the proportion of OTUs identified as Rickettsia sp. in wild-caught ticks increased from 2.2% (2/92) before feeding to as high as 46.8% (36/77) after feeding, and all Rickettsia spp. sequences recovered were most similar to those described from the spotted fever group Rickettsia, specifically R. amblyommii and R. massiliae. Additional characterization of the Rickettsiales tick community by polymerase chain reaction, cloning, and sequencing of 17 kDa and gltA genes confirmed these initial findings and suggested that novel Rickettsia spp. are likely present in these ticks. These data provide insight into the overall, as well as the rickettsial community of wild lone star ticks and may ultimately aid in identification of novel pathogens transmitted by A. americanum.
Kensinger, B J; Allan, B F
The carbon dioxide-baited trap is the most common and effective method for sampling vector life-stage Amblyomma americanum (L.) (Acari: Ixodidae), although confounding environmental variables are rarely considered. A mark-recapture experiment was designed to compare recapture proportions of A. americanum nymphs and adults between two habitat types: old field and oak-hickory forest. Powdered fluorescent dye was used to mark A. americanum ticks released in 1-m increments from carbon dioxide-baited traps. Adults were recaptured in significantly higher proportion than nymphs, but habitat type had no significant effect on recapture proportions. Tick abundance is an important parameter in the estimation of human risk of exposure to tick-borne disease and the influence of life stage on capture rates should be considered when calculating entomological risk.
Billeter, Sarah A; Miller, Melissa K; Breitschwerdt, Edward B; Levy, Michael G
Four hundred and sixty-six questing Amblyomma americanum (L.) (Acari: Ixodidae) from Carolina County, VA, and 98 questing A. americanum from Chatham County, NC, were screened by polymerase chain reaction (PCR) for the Bartonella 16S-23S intergenic spacer region. Two amplicons, approximately 270-280 bp, were detected in two ticks from Virginia. Based upon PCR and sequencing, an adult male and adult female tick harbored DNA sequences closely related to Bartonella tamiae (DQ395180). Bartonella DNA was not detected in A. americanum from North Carolina. Potential transmission of Bartonella spp. by A. americanum should be the focus of future experimental studies.
Mixson, T.R.; Campbell, S.R.; Gill, J.S.; Ginsberg, H.S.; Reichard, M.V.; Schultz, T.L.; Dasch, G.A.
Ambyomma antericanum (L.) (Acari: Ixodidae) is an aggressive tick that feeds on humans during all postembryonic life stages. In many regions of the United States, it is the tick most commonly found attached to humans. Public health interest has grown recently, due to the recognition of new human pathogens transmitted by A. antericanum and the expanding distribution of the tick. A. americanum is a vector of several bacteria pathogenic to humans. Ehrlichia chaffeensis and Ehrlichia ewingii cause moderate-to-severe febrile illness. 'Rickettsia amblyommii,' a member of the spotted fever group Rickettsia, also has recently been implicated as a possible human pathogen based on serologic evidence from persons recovering from illness after a tick bite. We have determined the prevalence of infection of Ehrlichia chaffeensis, E. ewingii, 'Borrelia lonestari,' and R. amblyommii within A. americanum ticks from 29 sites in nine states. Overall infection prevalences were 4.7% for E. chaffeensis (range, 0-27%), 3.5% for E. ewingii (range, 0-18.6%), 2.5% for B. lonestari (range, 0-12.2%), and 41.2% for R. amblyommii (range, 0-84.0%). In addition, 87 ticks (4.3%) were infected with two or more bacteria. This report documents new distribution records for E. ewingii, B. lonestari, and R. amblyommii and underscores the nonhomogeneous distribution of pathogen foci of infection. Additional surveillance throughout the range of A. antericanum is warranted to increase physician and public awareness of the risk of disease to humans from exposure to the agents transmitted by this tick.
Goessling, Lisa S; Allan, Brian F; Mandelbaum, Rachel S; Thach, Robert E
Unique oligonucleotide probes were synthesized to distinguish among closely related vertebrate mitochondrial rDNA sequences present in residual bloodmeals in emergent Amblyomma americanum (L.) (Acari: Ixodidae) nymph life-stage ticks. Use of these probes enabled the identification of the Eastern gray squirrel as an important bloodmeal source in nymphs harboring Ehrlichia and Borrelia species. These results were confirmed by identifying these same bacterial genera in Eastern gray squirrel tissues.
Schulze, Terry L; Jordan, Robert A; Healy, Sean P; Roegner, Vivien E; Meddis, Michael; Jahn, Margaret B; Guthrie, Douglas L
To evaluate their potential importance in the transmission of ixodid tick-borne borrelioses in Monmouth County, NJ, we collected host-seeking Ixodes scapularis Say and Amblyomma americanum (L.) (Acari: Ixodidae) adults and nymphs to determine relative encounter frequencies and the infection prevalence of selected Borrelia spp. in their respective tick vectors. We also reviewed records of all ticks submitted for identification by the public in Monmouth County during 2001-2005. Relative abundance of the two species varied markedly among sites. Adult encounter frequencies for the two species were similar; however, A. americanum nymphs were encountered 3 times more frequently than I. scapularis nymphs. Of 435 ticks submitted by the public, 50.1 and 38.9% were I. scapularis and A. americanum, respectively. However, during May through August, the peak Lyme disease transmission season in New Jersey, significantly more submitted ticks were A. americanum (55.9%), compared with I. scapularis (34.1%). Polymerase chain reaction analysis of 94 1. scapularis and 103 A. americanum adults yielded infection prevalences of 31.9% for B. burgdorferi and 5.8% for B. lonestari, respectively. Although the infection prevalence of B. burgdorferi in I. scapularis was considerably higher than the infection prevalence of B. lonestari in A. americanum, the higher encounter frequencies for A. americanum compared with I. scapularis observed in this and other studies may result in increased risk of acquiring exposure to A. americanum-transmitted pathogens. The potential public health implications of these results are discussed.
Ginsberg, H S; Ewing, C P; O'Connell, A F; Bosler, E M; Daley, J G; Sayre, M W
Lone star ticks, Amblyomma americanum comprised a significantly greater proportion of total ticks flagged on eastern Long Island and Fire Island, New York, in 1986 and 1990 than in samples reported by other authors from the 1940s (when A. americanum was not collected by flagging or from hosts) and the 1970s. Therefore, population densities of A. americanum apparently have increased in recent years on southeastern Long Island, where this species now is distributed widely.
Stromdahl, Ellen Y; Williamson, Phillip C; Kollars, Thomas M; Evans, Sandra R; Barry, Ryan K; Vince, Mary A; Dobbs, Nicole A
We used a nested PCR with Borrelia flagellin gene (flaB) primers and DNA sequencing to determine if Borrelia lonestari was present in Amblyomma americanum ticks removed from military personnel and sent to the Tick-Borne Disease Laboratory of the U.S. Army Center for Health Promotion and Preventive Medicine. In our preliminary investigation, we detected Borrelia sequences in 19 of 510 A. americanum adults and nymphs from Ft. A. P. Hill, Va. During the 2001 tick season, the flaB primers were used to test all A. americanum samples as they were received, and 29 of 2,358 A. americanum samples tested individually or in small pools were positive. PCRs with 2,146 A. americanum samples in 2002 yielded 26 more Borrelia-positive samples. The positive ticks in 2001 and 2002 were from Arkansas, Delaware, Kansas, Kentucky, Maryland, New Jersey, North Carolina, Tennessee, and Virginia. The last positive sample of the 2001 season was a pool of larvae. To further investigate larval infection, we collected and tested questing A. americanum larvae from Aberdeen Proving Ground, Md.; 4 of 33 pools (40 larvae per pool) were positive. Infection of unfed larvae provides evidence of the maintenance of B. lonestari by means of transovarial transmission. Sequence analysis revealed that the amplicons were identical to sequences of the B. lonestari flaB gene in GenBank. Despite the low prevalence of infection, the risk of B. lonestari transmission may be magnified because A. americanum is often abundant and aggressive, and many tick bite victims receive multiple bites.
Castellaw, A H; Showers, J; Goddard, J; Chenney, E F; Varela-Stokes, A S
In this study, we evaluated Amblyomma americanum (lone star tick) in Mississippi for the presence of Ehrlichia chaffeensis, causative agent of human monocytic ehrlichiosis; Ehrlichia ewingii, causative agent of human and canine granulocytic ehrlichiosis; Borrelia lonestari, putative agent of southern tick-associated rash illness; Francisella tularensis, the agent of tularemia; and Rickettsia spp., particularly R. amblyommii, a suspected pathogen. We collected adult A. americanum from four regions of Mississippi: Northeast, Northwest, Southeast, and East. Of the ticks collected, 192 were dissected and DNA was extracted for nested polymerase chain reaction (PCR) assays to detect the above bacteria. In all, 3% of tick extracts had evidence of Borrelia sp., 4% for E. chaffeensis, 6% for E. ewingii, and 44% for a Rickettsia species. As determined by sequencing, most Rickettsia spp. were R. amblyommii. In addition, extracts from 42 pools (total of 950) of larval A. americanum collected in Southwest Mississippi were tested for the presence of E. chaffeensis and Rickettsia species. Of these extracts from pools, nine of 37 (24%) were PCR positive for a Rickettsia sp., most often, R. amblyommii; none had evidence of E. chaffeensis, supporting the ability of lone star ticks to transovarially transmit R. amblyommii, but not E. chaffeensis. This study demonstrates E. chaffeensis, E. ewingii, "B. lonestari", and R. amblyommii in A. americanum by PCR for the first time in Mississippi. Understanding the prevalence and epidemiology of these agents in Mississippi should increase awareness of tick-borne disease in the medical community.
Stegall-Faulk, T; Clark, D C; Wright, S M
Genetic sequences characteristic of Borrelia lonestari (Barbour et al. 1996) were detected in two pools of adult Amblyomma americanum (L.) from Tennessee, corresponding to an estimated minimum field infection rate of 8.4 infected ticks/1000 adults. DNA amplification was conducted using primers derived from the B. lonestari flagellin gene that would also amplify Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt, and Brenner). Species-specific, internal probes were then used to differentiate between genetic sequences of the spirochetes. Subsequent nucleotide sequencing confirmed the presence of B. lonestari in A. americanum; B. burgdorferi was not detected. This represents the first report of B. lonestari from Tennessee, and suggests that Lyme-like illness may occur in Tennessee.
Stromdahl, E Y; Randolph, M P; O'Brien, J J; Gutierrez, A G
Human monocytic ehrlichiosis (HME) is a sometimes fatal, emerging tick-borne disease caused by the bacterium Ehrlichia chaffeensis. It is frequently misdiagnosed because its symptoms mimic those of the flu. Current evidence indicates that Amblyomma americanum (L.), the lone star tick, is the major vector of HME. To determine if E. chaffeensis is present in ticks at Aberdeen Proving Ground, MD, questing A. americanum ticks were collected from 33 sites. Nucleic acid was extracted from 34 adult and 81 nymphal pools. Sequences diagnostic for E. chaffeensis from three different loci (16S rRNA, 120-kDa protein, and a variable-length polymerase chain reaction [PCR] target, or VLPT) were targeted for amplification by the PCR. Fifty-two percent of the collection sites yielded pools infected with E. chaffeensis, confirming the presence and widespread distribution of E. chaffeensis at Aberdeen Proving Ground. Analysis with the both the 120-kDa protein primers and the VLPT primers showed that genetic variance exists. A novel combination of variance for the two loci was detected in two tick pools. The pathogenic implications of genetic variation in E. chaffeensis are as yet unknown.
Keirans, J E; Lacombe, E H
The first records of 3 ixodid tick species collected in the state of Maine are reported. A total of 23 records of the lone star tick, Amblyomma americanum (L., 1758), in 11 counties from hosts with no history of travel outside the state demonstrates that this tick is now a resident of Maine. Ixodes dentatus Marx, 1899 is recorded from Waldo and Lincoln counties, and Ixodes uriae White, 1852 is recorded from Matinicus Rock in Knox County. This is the first report of I. uriae from the eastern United States. Disease agents such as those causing human monocytic ehrlichiosis, Lyme disease, Rocky Mountain spotted fever, and several arboviruses have been recorded from 1 or more of these tick species.
Kollars, T M; Oliver, J H; Durden, L A; Kollars, P G
From June 1993 through June 1996, 2,260 adult, 4,426 nymphal, and 2,178 larval lone star ticks Amblyomma americanum (L.) were collected in Missouri from vertebrate hosts and by dragging a cloth over vegetation. Prevalence, mean intensity, and relative abundance of each stage varied among hosts. The relative abundance of adult lone star ticks was highest on white-tailed deer, but this stage was also collected from raccoons, opossum, red fox, coyotes, and wild turkey. Nymphs were collected from gray squirrels, eastern cottontail rabbits, opossums, red fox, Carolina wren, and bobwhite quail, but the highest relative abundance occurred on wild turkey, white-tailed deer, and raccoons. Eastern cottontail rabbits, white-tailed deer, raccoons, and squirrels had the highest relative abundance of larval lone star ticks, but they were also found on opossums and wild turkey. The activity of adult lone star ticks was greatest from May through July. The activity for nymphs was highest from May through August, and for larvae, July through September.
Berrada, Zenda L; Goethert, Heidi K; Cunningham, Jenny; Telford, Sam R
The role of lone star ticks as vectors for Rocky Mountain spotted fever (RMSF) remains poorly described. We compared the entomological inoculation rates (EIRs) for Rickettsia spp. for representative sites in Missouri and Kansas, states that frequently report RMSF each year. Host-seeking ticks were collected during 2006 and pooled tick homogenates analyzed by polymerase chain reaction to detect probable R. rickettsii, with confirmation for multiple gene targets performed on individual ticks from pools that screened positive. Of 870 adult and nymphal lone star ticks, Amblyomma americanum (L.), 0.46% contained DNA of Rickettsia rickettsii. Interestingly, two of these positive ticks were concurrently infected by R. amblyommii. More than 90% of lone star tick pools contained R. amblyommii DNA. Of 169 dog ticks that were analyzed, none were infected by R. rickettsii. The entomological inoculation rate for spotted fever group (SFG) rickettsiae within lone star ticks was an order of magnitude greater than that for dog ticks. We conclude that lone star ticks may be epidemiologically significant vectors of Rocky Mountain spotted fever and of spotted fever group rickettsiae.
Hilburn, L R; Sattler, P W
Nine populations of Amblyomma americanum (L.) were examined electrophoretically for variation of 21 enzymes. Only three enzymes were not polymorphic and the average heterozygosity per individual (h) for the species was 0.085 with a range of 0.077 to 0.110, comparing well with values in other arthropods. The average Nei identity value for pairwise comparisons among the nine populations was high, 0.994 +/- 0.004 (I +/- SD). These high identity values and the absence of geographic structuring of the protein variation suggest that this species is genetically homogeneous. Normal levels of genic variability within and a lack of divergence between populations were not predicted by models developed to describe these genetic characteristics on the basis of the heterogeneities encountered by parasites in their environment. An analysis of data from several different species of ticks suggests host mobility and abundance, as well as tick abundance and selectivity in choosing a host, are important parameters in determining genetic variation in these ectoparasites.
Ginsberg, H.S.; Butler, M.; Zhioua, E.
The effects of deer exclusion on northern populations of lone star ticks, Amblyomma americanum, were tested at the Lighthouse Tract, Fire Island, NY, USA, where densities of this species have increased recently. Game fencing was erected to exclude deer from two sites of roughly one ha each, and populations of nymphal and adult A. americanum within were compared with those at control sites outside the exclosures. Percent control of nymphs within vs. outside the exclosures averaged 48.4% in the four years post-treatment, compared to pretreatment values. Percent control varied markedly in different years, suggesting that factors in addition to deer densities had strong effects on population densities of A. americanum. Exclosures of this size did not control adult A. americanum. Effects of deer exclusion in this recently expanded northern population of A. americanum were similar to those that have been reported for southern populations of this species.
Ginsberg, Howard S; Butler, Mari; Zhioua, Elyes
The effects of deer exclusion on northern populations of lone star ticks, Amblyomma americanum, were tested at the Lighthouse Tract, Fire Island, NY, USA, where densities of this species have increased recently. Game fencing was erected to exclude deer from two sites of roughly one ha each, and populations of nymphal and adult A. americanum within were compared with those at control sites outside the exclosures. Percent control of nymphs within vs. outside the exclosures averaged 48.4% in the four years post-treatment, compared to pretreatment values. Percent control varied markedly in different years, suggesting that factors in addition to deer densities had strong effects on population densities of A. americanum. Exclosures of this size did not control adult A. americanum. Effects of deer exclusion in this recently expanded northern population of A. americanum were similar to those that have been reported for southern populations of this species.
Eight commercially available essential oils (oregano, clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint) were evaluated for repellency against host-seeking nymphs of the lone star tick, Amblyomma americanum. Concentration- repellency response was established using the vertical ...
Carroll, J F; Paluch, G; Coats, J; Kramer, M
The essential oil from Amyris balsamifera (Rutaceae) and elemol, a principal constituent of the essential oil of Osage orange, Maclura pomifera (Moraceae) were evaluated in in vitro and in vivo laboratory bioassays for repellent activity against host-seeking nymphs of the blacklegged tick, Ixodes scapularis, and the lone star tick, Amblyomma americanum. Both bioassays took advantage of the tendency of these host-seeking ticks to climb slender vertical surfaces. In one bioassay, the central portion of a vertical strip of filter paper was treated with test solution and ticks placed or allowed to crawl onto the untreated lower portion. In the other bioassay, a strip of organdy cloth treated with test solution was doubly wrapped (treatment on outer layer) around the middle phalanx of a forefinger and ticks released on the fingertip. Both amyris oil and elemol were repellent to both species of ticks. Elemol did not differ significantly in effectiveness against A. americanum from the widely used repellent deet. At 2 and 4 h after application to filter paper, 827 microg amyris oil/cm(2) paper repelled 80 and 55%, respectively, of A. americanum nymphs. Ixodes scapularis was repelled by lower concentrations of amyris oil and elemol than A. americanum.
Proteomic analyses were done on 2 chemosensory appendages of the lone star tick, Amblyomma americanum. Proteins in the fore tarsi, which contain the olfactory Haller's organ, and in the palps, that include gustatory sensilla, were compared with proteins in the third tarsi. Also, male and female tick...
The essential oil nootkatone has shown acaricidal activity on ticks. The toxicity of nootkatone was determined in laboratory assays using a vial coating technique against unfed nymphs of four Ixodid ticks: Amblyomma americanum L., Dermacentor variabilis (Say), Ixodes scapularis Say, and Rhipicepha...
Carroll, J F; Kramer, M
The relative potential for a person accidentally acquiring host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say, and lone star tick, Amblyomma americanum (L.), while wearing either of two types of footwear, walking, crawling on hands and knees, and sitting on large fallen logs in deciduous woods, was evaluated. Although flag samples indicated substantial populations of I. scapularis nymphs and low to moderate numbers of A. americanum at the study sites, relatively few I. scapularis and fewer still A. americanum nymphs were acquired during 30-s and 5-min walks. Significantly fewer I. scapularis were picked up when boots were, worn with ankles taped (an anti-tick precaution) than when sneakers were worn with socks exposed during 5-min walks, but when thus attired, there was no significant difference between the number of nymphs acquired during 30-s walks. Nymphs of I. scapularis did not appear to accumulate incrementally on footwear or clothing during walks when boots were worn and ankles taped. Crawling for 30 s (approximately 3 m distance) yielded significantly more I. scapularis nymphs than walking for 30 s. During crawling, I. scapularis nymphs were picked up on 58% of the 30-s samples. Most ticks picked up during crawls were on pant legs. When a flannel flag cloth (0.5 by 0.5 m) was appressed to the upper surface of logs suitable to be sat upon by tired hikers, I. scapularis nymphs were found on 87% of the logs and in 36% of the samples. These data indicate that the potential for contact with host-seeking nymphs of I. scapularis occurring at these densities is greatly elevated by engaging in activities that involve contact with fallen logs and close contact of hands and knees with leaf litter.
Ginsberg, H.S.; Zhioua, E.
The distribution and survival of Ixodes scapularis and Amblyomma americanum were studied in deciduous and coniferous wooded habitats and in open habitats on Fire Island, New York, USA. The survival of nymphal I. scapularis in field enclosures was greater in forests than in open habitats, suggesting that greater survival contributes to the higher tick population in the woods. The nymphs of each species were more common in deciduous thickets (predominantly Aronia arbutifolia and Vaccinium corynbosum) than in coniferous woods (mostly Pinus rigida) in most but not all years. Larval I. scapularis were more common in coniferous sites in 1994, while the same ticks, as nymphs, were more common in deciduous sites in 1995. The survival of the nymphs was not consistently greater in either the deciduous or coniferous woods. Therefore, factors other than nymphal survival (e.g. larval overwintering survival and tick movement on hosts) probably influenced the relative nymph abundance in different forest types. Overall, the survival of A. americanum was far higher than that of I. scapularis.
Bibbs, Christopher S; Xue, Rui-De
The ThermaCELL with allethrin and OFF! Clip-on with metofluthrin were tested in a 939 m(2) vented enclosure against nymphal lone star ticks, Amblyomma americanum (L.). Repellency assays were conducted at varying distances relative to product specifications for repellency range. Nymphal ticks acclimated for 24 h in chambers attached to 10 repellency tracks per repetition. Devices were turned on, and the tick travel distance and delay until beginning to travel were recorded. Mortality of ticks was recorded after 24 h. Mortality assays were also conducted at the same distances with five ticks per cage, and 12 cages per distance radially distributed around a device. Cages were removed after 5 min, 15 min, 30 min, and 60 min of exposure and checked after 24 h for mortality. Significant travel distance was found when exposed to the ThermaCELL and OFF! Clip-on at their shortest test distances. Significant mortality also resulted at the same distances. Ticks exposed to active devices for longer than 15 min had significant mortality at the shortest distance for OFF! Clip-on and multiple distances for the ThermaCELL. Overall, the spatial repellent devices ThermaCELL with allethrin and OFF! Clip-on with metofluthrin both demonstrated desirable effects when tested against A. americanum nymphs. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Meng, Hao; Li, Andrew Y; Costa Junior, Livio M; Castro-Arellano, Ivan; Liu, Jingze
DEET and Eight commercially available essential oils (oregano, clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint) were evaluated for repellency against host-seeking nymphs of the lone star tick, Amblyomma americanum. Concentration-repellency response was established using the vertical paper bioassay technique for each essential oil and compared with that of N,N-diethyl-3-methyl benzamide (DEET), a standard repellent compound present in many commercial repellent formulations. The effective concentration of DEET that repels 50% of ticks (EC50) was estimated at 0.02 mg/cm(2), while EC50s of the essential oils fall between 0.113 and 0.297 mg/cm(2). Based on EC50 estimates, oregano essential oil was the most effective among all essential oils tested, followed by clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint oils. None of the tested essential oils demonstrated a level of tick repellency found with DEET. Results from this study illustrated the challenge in search for more effective natural tick repellents.
Carroll, J F; Solberg, V B; Klun, J A; Kramer, M; Debboun, M
The repellents N,N-diethyl-3-methylbenzamide (deet) and racemic 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (AI3-37220) were evaluated using two different laboratory bioassays to determine their relative effectiveness against host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say, and the lone star tick, Amblyomma americanum (L.). In a petri dish bioassay, ticks were released within a ring of repellent on a horizontal filter paper disk. In the second bioassay, ticks were allowed to climb a vertical strip of filter paper whose central portion was treated with a repellent. Deet and AI3-37220 were more effective against I. scapularis than A. americanum nymphs. In the petri dish bioassay, none of the concentrations of deet or AI3-37220 tested confined A. americanum within the treated ring. However, in the vertical bioassay, both species exhibited avoidance of the repellents, and I. scapularis was repelled by much lower concentrations than A. americanum. I. scapularis were repelled by lower concentrations in the vertical bioassay than in the petri dish bioassay. Deet was slightly more effective against I. scapularis than AI3-37220 in both bioassays, but AI3-37220 was significantly more effective than deet against A. americanum in the vertical bioassay.
Reichard, M V; Kocan, A A; Van Den Bussche, R A; Barker, R W; Wyckoff, J H; Ewing, S A
Sequence analysis of the ribosomal DNA second internal transcribed spacer (ITS 2) region in 2 spatially distinct populations of Amblyomma americanum (L.) revealed intraspecific variation. Nucleotide sequences from multiple DNA extractions and several polymerase chain reaction amplifications of eggs from mixed-parentage samples from both populations of ticks revealed that 12 of 1,145 (1.0%) sites varied. Three of the 12 sites of variation were distinct between the 2 A. americanum populations, which corresponded to a rate of 0.26%. Phylogenetic analysis based on ITS 2 sequences provided strong support (i.e., bootstrap value of 80%) that wild A. americanum clustered into a distinguishable group separate from those derived from colony ticks.
The lone star tick, Amblyomma americanum (L.), is a widely distributed three-host obligate blood-feeding parasite in the United States and Mexico. It mostly attaches to white-tailed deer, Odocoilus virginianus (Zimmerman) and wild turkey, Meleagris gallopavo L., as well as a wide variety of other do...
Flor-Weiler, Lina B; Behle, Robert W; Stafford, Kirby C
Toxicity of nootkatone was determined in laboratory assays against unfed nymphs of Amblyomma americanum L., Dermacentor variabilis (Say), Ixodes scapularis Say, and Rhipicephalus sanguineus Latreille. We determined the 50% lethal concentration (LC50) and 90% lethal concentration (LC90) of nootkatone by recording tick mortality 24 h after exposure in treated glass vials. Nymphs were susceptible to nootkatone with LC50 values of 0.352, 0.233, 0.169, and 0.197 microg/cm2, and LC90 values of 1.001, 0.644, 0.549, and 0.485 microg/cm2 for A. americanum, D. variabilis, I. scapularis, and R. sanguineus, respectively. The LC50 value for R. sanquineus was not significantly different from D. variabilis or I. scapularis. Other LC50 comparisons were significantly different. The LC90 for A. americanum was higher when compared with the three other tick species, which were not significantly different. Because nootkatone is volatile, we measured the amount of nootkatone recovered from duplicate-treated vials before tick exposure and from vials after tick exposure. Nootkatone recovered from vials before exposure ranged from 82 to 112% of the expected amounts. The nootkatone recovered after the 24-h exposure period ranged from 89% from vials coated with higher concentrations of nootkatone, down to 29% from vials coated with low nootkatone concentrations. Determination of the nootkatone residue after vial coating demonstrated loss of the active compound while verifying the levels of tick exposure. Toxicity of low concentrations of nootkatone to the active questing stage of ticks reported in this study provides a reference point for future formulation research to exploit nootkatone as a safe and environment-friendly tick control.
Ludwig, Antoinette; Ginsberg, Howard; Hickling, Graham J.; Ogden, Nicholas H.
The lone star tick, Amblyomma americanum, is a disease vector of significance for human and animal health throughout much of the eastern United States. To model the potential effects of climate change on this tick, a better understanding is needed of the relative roles of temperature-dependent and temperature-independent (day-length-dependent behavioral or morphogenetic diapause) processes acting on the tick lifecycle. In this study, we explored the roles of these processes by simulating seasonal activity patterns using models with site-specific temperature and day-length-dependent processes. We first modeled the transitions from engorged larvae to feeding nymphs, engorged nymphs to feeding adults, and engorged adult females to feeding larvae. The simulated seasonal patterns were compared against field observations at three locations in United States. Simulations suggested that 1) during the larva-to-nymph transition, some larvae undergo no diapause while others undergo morphogenetic diapause of engorged larvae; 2) molted adults undergo behavioral diapause during the transition from nymph-to-adult; and 3) there is no diapause during the adult-to-larva transition. A model constructed to simulate the full lifecycle of A. americanum successfully predicted observed tick activity at the three U.S. study locations. Some differences between observed and simulated seasonality patterns were observed, however, identifying the need for research to refine some model parameters. In simulations run using temperature data for Montreal, deterministic die-out of A. americanum populations did not occur, suggesting the possibility that current climate in parts of southern Canada is suitable for survival and reproduction of this tick.
Ludwig, Antoinette; Ginsberg, Howard S; Hickling, Graham J; Ogden, Nicholas H
The lone star tick, Amblyomma americanum, is a disease vector of significance for human and animal health throughout much of the eastern United States. To model the potential effects of climate change on this tick, a better understanding is needed of the relative roles of temperature-dependent and temperature-independent (day-length-dependent behavioral or morphogenetic diapause) processes acting on the tick lifecycle. In this study, we explored the roles of these processes by simulating seasonal activity patterns using models with site-specific temperature and day-length-dependent processes. We first modeled the transitions from engorged larvae to feeding nymphs, engorged nymphs to feeding adults, and engorged adult females to feeding larvae. The simulated seasonal patterns were compared against field observations at three locations in United States. Simulations suggested that 1) during the larva-to-nymph transition, some larvae undergo no diapause while others undergo morphogenetic diapause of engorged larvae; 2) molted adults undergo behavioral diapause during the transition from nymph-to-adult; and 3) there is no diapause during the adult-to-larva transition. A model constructed to simulate the full lifecycle of A. americanum successfully predicted observed tick activity at the three U.S. study locations. Some differences between observed and simulated seasonality patterns were observed, however, identifying the need for research to refine some model parameters. In simulations run using temperature data for Montreal, deterministic die-out of A. americanum populations did not occur, suggesting the possibility that current climate in parts of southern Canada is suitable for survival and reproduction of this tick.
Ginsberg, H S; Ewing, C P
Ticks were sampled by flagging, collecting from the investigator's clothing (walking samples), trapping with dry-ice bait, and collecting from mammal hosts on Fire Island, NY, U.S.A. The habitat distribution of adult deer ticks, Ixodes dammini, was the same in simultaneous collections from the investigator's clothing and from muslin flags. Walking and flagging samples can both be biased by differences between investigators, so the same person should do comparative samples whenever possible. Walking samples probably give a more accurate estimate than flagging samples of the human risk of encountering ticks. However, ticks (such as immature I. dammini) that seek hosts in leaf litter and ground-level vegetation are poorly sampled by walking collections. These ticks can be sampled by flagging at ground level. Dry-ice-baited tick-traps caught far more lone-star ticks, Amblyomma americanum, than deer ticks, even in areas where deer ticks predominated in flagging samples. In comparisons of tick mobility in the lab, nymphal A. americanum were more mobile than nymphal I. dammini in 84% of the trials. Therefore, the trapping bias may result from increased trap encounter due to more rapid movement by A. americanum, although greater attraction to carbon dioxide may also play a role. Tick traps are useful for intraspecific between-habitat comparisons. Early in their seasonal activity period, larval I. dammini were better represented in collections from mouse hosts than in flagging samples. Apparently, sampling from favored hosts can detect ticks at low population levels, but often cannot be used to get accurate estimates of pathogen prevalence in questing ticks.
Bacon, Rendi Murphree; Pilgard, Mark A; Johnson, Barbara J B; Piesman, Joseph; Biggerstaff, Brad J; Quintana, Miguel
DNA was extracted from pools of Amblyomma americanum ticks collected from vegetation at two sites in Fort Leonard Wood, Missouri and tested for the presence of Borrelia spp. Two new methods were developed to detect Borrelia lonestari DNA by targeting the glycerophosphodiester phosphodiesterase (glpQ) gene. The first method detected B. lonestari DNA using a SYBR green I melting curve analysis of the PCR product obtained with glpQ gene primers. The second method, a glpQ TaqMan assay, detected and confirmed the presence of B. lonestari glpQ-specific sequences. Twenty-two of 95 tick pools collected at site A148 contained B. lonestari DNA. None of 19 pools from site A241 contained B. lonestari DNA. No B. burgdorferi sensu lato DNA was detected using a SYBR green I melting curve analysis of the PCR product obtained with outer surface protein A (ospA) primers. The overall B. lonestari infection prevalence (with 95% confidence interval) at site A148 was estimated using two algorithms: minimum infection rate 4.14% (2.45, 5.84) and maximum likelihood with correction 4.82% (3.11, 7.16). The merits of each are discussed. Sequencing of the entire B. lonestari glpQ and partial 16S rRNA genes revealed two genetic variants circulating in this population of A. americanum from Missouri.
Chalaire, Katelyn Cox; Kim, Tae Kwon; Garcia-Rodriguez, Heidy; Mulenga, Albert
In order to successfully feed and transmit disease agents, ticks are thought to inject serine protease inhibitors (serpins) into the host to modulate host defense responses to tick feeding, such as inflammation, the complement activation pathway and blood coagulation. In this study, we show that Amblyomma americanum (Aam) serpin (S) 6 is putatively injected into the host during tick feeding, in that the antibody to recombinant (r) AamS6 specifically reacted with the expected ∼43/45 kDa AamS6 protein band on western blots of pilocarpine-induced tick saliva. Additionally, antibodies to tick saliva proteins that were generated by repeated 48 h infestations of rabbits with adult A. americanum specifically reacted with rAamS6. We speculate that AamS6 is associated with regulating events at the start of the tick feeding process, as temporal and spatial RT-PCR and western blot analyses revealed that both AamS6 mRNA and protein are strongly expressed during the first 24-72 h of feeding time before starting to fade from 96 h. The AamS6 protein has an apparently slow turnover rate in that, although the injection of AamS6 dsRNA into unfed ticks triggered complete disruption of the AamS6 mRNA by the 48 h feeding time point, western blot analysis of protein extracts of the same animals showed that the AamS6 protein that may have been expressed prior to disruption of the AamS6 mRNA was not depleted. We speculate that the presence of the AamS6 protein in ticks despite the complete disruption of the AamS6 mRNA explains the observation that RNAi-mediated silencing of the AamS6 mRNA did not affect the ability of A. americanum ticks to attach onto host skin, successfully feed and lay eggs. These findings are discussed in regards to advances in the molecular biology of ticks.
Sayler, Katherine A; Loftis, Amanda D; Beatty, Sarah K; Boyce, Carisa L; Garrison, Elina; Clemons, Bambi; Cunningham, Mark; Alleman, Arthur R; Barbet, Anthony F
Amblyomma americanum (L.), the lone star tick, is an aggressive tick that is expanding its geographic range within the United States. This tick is the vector for the human and veterinary pathogens Ehrlichia chaffeensis and Ehrlichia ewingii and is associated with other microbes of unspecified pathogenicity including Rickettsia amblyommii, Panola Mountain Ehrlichia, and Borrelia lonestari In Florida, there has been sparse contemporary data on the prevalence of these organisms in host-seeking lone star ticks. To determine the prevalence of this tick and associated microbes in North Central Florida state parks, ∼1,500 lone star tick specimens were collected between 2010 and 2012 analyzed by polymerase chain reaction (PCR) sequencing. Additionally, 393 white-tailed deer, Odocoileus virginianus (Zimmerman), samples were analyzed for pathogen prevalence using molecular methods and serology. In lone star ticks, 14.6, 15.6, and 57.1% were positive for E. chaffeensis, E. ewingii, and Rickettsia spp. DNA, respectively. Panola Mountain Ehrlichia or B. lonestari DNA were each detected in nearly 2% of tick specimens. In white-tailed deer, 7.3% were PCR positive for E. chaffeensis, 6.0% for E. ewingii, and 3.2% for rickettsial species. Approximately 45% of white-tailed deer specimens had antibodies to Ehrlichia spp., and <1% had antibodies to Borrelia burgdorferi In summary, E. chaffeensis, E. ewingii, and spotted fever group rickettsia are highly prevalent in host-seeking lone star ticks and in white-tailed deer in Florida. The molecular and serological evidence of these microbes underscore their zoonotic potential in this region. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Maegli, Amanda; Loy, J Dustin; Cortinas, Roberto
The lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), is established in southeastern Nebraska yet the prevalence of tick-associated microorganisms is not known. An initial PCR-based analysis for Ehrlichia chaffeensis, Ehrlichia ewingii, and Borrelia infection in host-seeking adult ticks collected in southeast Nebraska was conducted. A total of 251 adult ticks collected in six sites in southeast Nebraska were tested. E. chaffeensis, E. ewingii, and Borrelia spp. were present, and the prevalence of each was approximately 1.6%. This study demonstrates that Ehrlichia spp. are present in Nebraska lone star tick populations.
et al. 1998). Oliver et al. (1987) described the immature stages of I. affinis and provided distribution, phenology , and host records. Ixodes...Ixodes (Ixodes) scapularis (Acari: Ixodidae): Redescription of all active stages, distribution, hosts, geographical variation , and medical and
Mastropaolo, Mariano; Beltrán-Saavedra, L Fabián; Guglielmone, Alberto A
The tick species reported in Bolivia are reviewed here as (1) endemic or established: Ornithodoros echimys, O. guaporensis, O. hasei, O. kohlsi, O. mimon, O. peropteryx, O. rostratus, Otobius megnini, Amblyomma auricularium, A. cajennense, A. calcaratum, A. coelebs, A. dubitatum, A. humerale, A. incisum, A. longirostre, A. naponense, A. nodosum, A. oblongoguttatum, A. ovale, A. parvitarsum, A. parvum, A. pecarium, A. pseudoconcolor, A. rotundatum, A. scalpturatum, A. tigrinum, A. triste, Dermacentor nitens, Haemaphysalis juxtakochi, H. leporispalustris, I. boliviensis, I. cooleyi, I. luciae, Rhipicephalus microplus, R. sanguineus, and (2) erroneously reported: Ornithodoros puertoricensis, O. talaje, O. turicata, Amblyomma americanum, A. maculatum, A. multipunctum, Ixodes ricinus, I. scapularis, Rhipicephalus annulatus. Many of these records are lacking locality and/or host, and some of them need new findings for confirmation. Some of the species recorded may represent a threat for human and animal health, therefore would be of great value to make a countrywide survey of ticks in order to update the information presented in this work.
MENTZ, Márcia Bohrer; TROMBKA, Marcelo; da SILVA, Guilherme Liberato; SILVA, Carlos Eugênio
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
The southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini), is a haematophagous arachnid (Acari: Ixodidae) recognized globally as an economically important ectoparasite of cattle in tropical and subtropical agroecosystems. Populations of this invasive tick species around the wo...
Horak, Ivan G; Apanaskevich, Dmitry A; Kariuki, Edward K
A new tick species belonging to the genus Rhipicephalus Koch, 1844 (Acari: Ixodidae), namely, Rhipicephalus walkerae n. sp., is described. The male and female of this species are similar to those of several species in the Rhipicephalus appendiculatus group but can be distinguished from them by the very dense pattern of medium-sized punctations covering the conscutum and scutum, long and narrow dorsal prolongation of the spiracular plate, and relatively short dorsal cornua; in addition, the male has long and narrow adanal plates without a posterolateral angle. R. walkerae is known only from Kenya, where the adults were collected from giraffes, Giraffa camelopardalis (L.).
Barrett, Anne W; Noden, Bruce H; Gruntmeir, Jeff M; Holland, Taylor; Mitcham, Jessica R; Martin, Jaclyn E; Johnson, Eileen M; Little, Susan E
Geographic distribution records for the lone star tick [Amblyomma americanum (L.)] in the peer-reviewed literature are incomplete for Oklahoma, preventing accurate disease risk assessments. To address this issue and document the presence of A. americanum in available habitats throughout the state, county-scale tick records published in U.S. Department of Agriculture-Cooperative Economic Insect Reports and specimens maintained at the K.C. Emerson Entomology Museum, Oklahoma State University, were reviewed. In addition, dry ice traps and tick drags were used to collect adult and nymphal A. americanum from throughout the state. Review of published USDA reports and the local museum collection documented A. americanum in 49 total counties (35 and 35, respectively). Active surveillance efforts confirmed the presence of this tick in 50 counties from which this species had not been previously reported to be established, documenting A. americanum is established in 68 of the 77 (88.3%) counties in Oklahoma. Taken together, these data verify that A. americanum ticks are much more widespread in Oklahoma than reflected in the literature, a phenomenon likely repeated throughout the geographic range of this tick in the eastern half of North America. © The Author 2015. Published by Oxford University Press on behalf of Entomological Society of America.All rights reserved. For Permissions, please e-mail: firstname.lastname@example.org.
Todd, S M; Sonenshine, D E; Hynes, W L
The transcript sequence of the Amblyomma americanum Linnaeus (Acari: Ixodidae) defensin, termed amercin (amn), was ascertained and a 219-bp amn coding region identified. The gene encodes a 72-amino acid prepropeptide with a putative 37-amino acid mature peptide. This gene shows little similarity to either of the defensins from Amblyomma hebraeum Koch, the only other Amblyomma species for which a defensin has been described. Sequence comparisons with other tick defensins reveal amn to be shorter (6 bp or 2 amino acids) than the Ixodes scapularis Linnaeus (Acari: Ixodidae) and Dermacentor variabilis (Say) (Acari: Ixodidae) defensin sequences. The amercin prepropeptide has 60.8% and 59.5% similarity with the I. scapularis and D. variabilis prepropeptides, respectively, whereas the mature amercin peptide has 73.7% and 71.1% similarity with the mature peptides of these ticks. Similarity with other tick defensins ranges from 42% to 71%. In A. americanum, defensin transcript was found in the midgut, fat body and salivary gland tissues, as well as in the haemocytes. Defensin transcript was also present in early-stage eggs (less than 48 h old), late-stage eggs (approximately 2 weeks old), larvae and nymphs of A. americanum and I. scapularis, both of which are vector-competent for Borrelia spirochetes.
Warburton 1911), Haemaphysalis (Nuttall and Warburton 1915), Amblyomma (Robinson 1926) and the works of Neumann (e.g., 1899, 1901, 1911). Most of these...synonymy). Although dated, the only one of these that is of real value today is that on Amblyomma , both for its keys to the adult stages and its fine...1993 Ixodidae Amblyomma 12 Petney 1993 Aponommaa 9 Petney 1993 Boophilusb 1 Petney and Keirans 1996 Dermacentor 5 Petney and Keirans 1996 Haemaphysalis
Nava, Santiago; Beati, Lorenza; Dunlop, Jason; Guglielmone, Alberto A
Herein, Amblyomma tenellumKoch, 1844 (Ixodidae) is reestablished as a valid tick name and removed from the synonymy list of Amblyomma cajennense (Fabricius, 1787), while Amblyomma imitatorKohls, 1958, is relegated to a junior synonym of A. tenellum. Amblyomma tenellum is redescribed based on the examination of male type specimens collected by Deppe at the beginning of the 19th century in Mexico and described by Koch in 1844. Copyright © 2014 Elsevier GmbH. All rights reserved.
SPRINGER, YURI P.; EISEN, LARS; BEATI, LORENZA; JAMES, ANGELA M.; EISEN, REBECCA J.
In addition to being a major nuisance biter, the lone star tick, Amblyomma americanum (L.), is increasingly recognized as an important vector of pathogens affecting humans, domestic animals, and wildlife. Despite its notoriety, efforts have been lacking to define the spatial occurrence of A. americanum in the continental United States with precision beyond that conveyed in continental-scale distribution maps. Here we present a county-level distribution map for A. americanum generated by compiling collection records obtained from a search of the published literature and databases managed by the USDA, U.S. National Tick Collection, and Walter Reed Biosystematics Unit. Our decadal and cumulative maps, which visually summarize 18,121 collections made between 1898 and 2012, show that A. americanum is either established (≥six ticks or ≥two life stages) or reported (
Maestas, Lauren P; Adams, Seryna L; Britten, Hugh B
Ixodes scapularis Say (Acari: Ixodidae) is the most important vector of human disease in the United States. Recent efforts by public health officials to determine its presence on a county-by-county basis have been undertaken to assist in Lyme disease risk assessment. Recent modeling efforts show that South Dakota can potentially support populations of I. scapularis based on favorable climatic conditions and presence of suitable hosts to support tick populations within the state. We provide the first documentation of an established population of I. scapularis in Clay County, SD, providing only the third record of the presence of this tick species within the state. 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.
Miranda-Miranda, E; Cossio-Bayugar, R; Martínez-Ibañez, F; Casasanero-Orduña, R; Folch-Mallol, J
The purpose of this study was to describe an unreported entomopathogenic fungus that naturally infects the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). Engorged female ticks, showed symptoms of fungal infection after controlled tick infestation of cattle. Infected ticks developed a distinctive dark colour, a pale mould grew over the cuticle and the ticks eventually died covered with fungal conidiophores. The responsible fungus was isolated and cultured on mycological medium and submitted to microscopic morphology, biochemical phenotyping and 18S rRNA ribotyping analyses, which identified it as aflatoxin-producing Aspergillus flavus. Spores from the cultured fungus were experimentally sprayed over healthy engorged female ticks, obtaining an 80% prevalence of experimental infection of healthy ticks and their egg masses, the larval progeny after incubation under laboratory conditions was also infected. These results demonstrate that A. flavus is the causative agent of the natural fungal disease of the cattle tick R. microplus described here.
Koc, Samed; Oz, Emre; Aydın, Levent; Cetin, Huseyin
Acaricidal effects of three Labiatae essential oils extracted from ariel parts of Thymus sipyleus Boiss. subsp. sipyleus, Mentha longifolia L., and Dorystoechas hastata Boiss. & Heldr. ex Bentham on 10-day-old Rhipicephalus turanicus Pom. (Acari: Ixodidae) larvae were evaluated by using the larval packet test bioassay. Serial dilutions of the three essential oils were tested from a starting concentration of 1-0.1% (1.0, 0.5, 0.25, and 0.1% w/v). Results showed that all essential oils had very similar activity, producing complete mortality (100%) in all tested concentrations on 10-day-old R. turanicus tick larvae.
Labruna, Marcelo B; Jorge, Rodrigo S P; Sana, Dênis A; Jácomo, Anah Tereza A; Kashivakura, Cyntia K; Furtado, Mariana M; Ferro, Claudia; Perez, Samuel A; Silveira, Leandro; Santos, Tarcísio S; Marques, Samuel R; Morato, Ronaldo G; Nava, Alessandra; Adania, Cristina H; Teixeira, Rodrigo H F; Gomes, Albério A B; Conforti, Valéria A; Azevedo, Fernando C C; Prada, Cristiana S; Silva, Jean C R; Batista, Adriana F; Marvulo, Maria Fernanda V; Morato, Rose L G; Alho, Cleber J R; Pinter, Adriano; Ferreira, Patrícia M; Ferreira, Fernado; Barros-Battesti, Darci M
The present study reports field data of ticks infesting wild carnivores captured from July 1998 to September 2004 in Brazil. Additional data were obtained from one tick collection and from previous published data of ticks on carnivores in Brazil. During field work, a total of 3437 ticks were collected from 89 Cerdocyon thous (crab-eating fox), 58 Chrysocyon brachyurus (maned wolf), 30 Puma concolor (puma), 26 Panthera onca (jaguar), 12 Procyon cancrivorus (crab-eating raccoon), 4 Speothos venaticus (bush dog), 6 Pseudalopex vetulus (hoary fox), 6 Nasua nasua (coati), 6 Leopardus pardalis (ocelot), 2 Leopardus tigrinus (oncilla), 1 Leopardus wiedii (margay), 1 Herpailurus yagouaroundi (jaguarundi), 1 Oncifelis colocolo (pampas cat), 1 Eira barbara (tayara), 1 Galictis vittata (grison), 1 Lontra longicaudis (neotropical otter), and 1 Potus flavus (kinkajou). Data obtained from the Acari Collection IBSP included a total of 381 tick specimens collected on 13 C. thous, 8 C. brachyurus, 3 P. concolor, 10 P. onca, 3 P. cancrivorus, 4 N. nasua, 1 L. pardalis, 1 L. wiedii, 4 H. yagouaroundi, 1 Galictis cuja (lesser grison), and 1 L. longicaudis. The only tick-infested carnivore species previously reported in Brazil, for which we do not present any field data are Pseudalopex gymnocercus (pampas fox), Conepatus chinga (Molina's hog-nosed skunk), and Conepatus semistriatus (striped hog-nosed skunk). We report the first tick records in Brazil on two Felidae species (O. colocolo, H. yagouaroundi), two Canidae species (P. vetulus, S. venaticus), one Procyonidae species (P. flavus) and one Mustelidae (E. barbara). Tick infestation remains unreported for 5 of the 26 Carnivora species native in Brazil: Oncifelis geoffroyi (Geoffroy's cat), Atelocynus microtis (short-eared dog), Pteronura brasiliensis (giant otter), Mustela africana (Amazon weasel), and Bassaricyon gabbii (olingo). Our field data comprise 16 tick species represented by the genera Amblyomma (12 species), Ixodes (1
Rulison, Eric L.; Kuczaj, Isis; Pang, Genevieve; Hickling, Graham J.; Tsao, Jean I.; Ginsberg, Howard S.
The nymphal stage of the blacklegged tick, Ixodes scapularis (Acari: Ixodidae), is responsible for most transmission of Borrelia burgdorferi, the etiologic agent of Lyme disease, to humans in North America. From 2010 to fall of 2012, we compared two commonly used techniques, flagging and dragging, as sampling methods for nymphal I. scapularis at three sites, each with multiple sampling arrays (grids), in the eastern and central United States. Flagging and dragging collected comparable numbers of nymphs, with no consistent differences between methods. Dragging collected more nymphs than flagging in some samples, but these differences were not consistent among sites or sampling years. The ratio of nymphs collected by flagging vs dragging was not significantly related to shrub density, so habitat type did not have a strong effect on the relative efficacy of these methods. Therefore, although dragging collected more ticks in a few cases, the numbers collected by each method were so variable that neither technique had a clear advantage for sampling nymphal I. scapularis.
El-Seedi, Hesham R; Azeem, Muhammad; Khalil, Nasr S; Sakr, Hanem H; Khalifa, Shaden A M; Awang, Khalijah; Saeed, Aamer; Farag, Mohamed A; AlAjmi, Mohamed F; Pålsson, Katinka; Borg-Karlson, Anna-Karin
Due to the role of Ixodes ricinus (L.) (Acari: Ixodidae) in the transmission of many serious pathogens, personal protection against bites of this tick is essential. In the present study the essential oils from 11 aromatic Egyptian plants were isolated and their repellent activity against I. ricinus nymphs was evaluated Three oils (i.e. Conyza dioscoridis L., Artemisia herba-alba Asso and Calendula officinalis L.) elicited high repellent activity in vitro of 94, 84.2 and 82%, respectively. The most active essential oil (C. dioscoridis) was applied in the field at a concentration of 6.5 µg/cm(2) and elicited a significant repellent activity against I. ricinus nymphs by 61.1%. The most repellent plants C. dioscoridis, C. officinalis and A. herba-alba yielded essential oils by 0.17, 0.11 and 0.14%, respectively. These oils were further investigated using gas chromatography-mass spectrometry analysis. α-Cadinol (10.7%) and hexadecanoic acid (10.5%) were the major components of C. dioscoridis whereas in C. officinalis, α-cadinol (21.2%) and carvone (18.2%) were major components. Artemisia herba-alba contained piperitone (26.5%), ethyl cinnamate (9.5%), camphor (7.7%) and hexadecanoic acid (6.9%). Essential oils of these three plants have a potential to be used for personal protection against tick bites.
Ernieenor, F C L; Ernna, G; Mariana, A
Morphotaxonomy based on phenotypic traits of immature hard ticks (Acari: Ixodidae) is a skill challenge and has prompted many inexperienced acarologists to adopt DNA-based methods for identifying and discriminating the species. The aim of this study is therefore to utilize COI gene for verifying the morphological status of Haemaphysalis ticks in Peninsular Malaysia. A total of 19 on-host ticks collected from four localities were first identified using specific illustrated taxonomic keys that lead to the genus of Haemaphysalis. Genotypic traits of tick species were then verified molecularly based on cytochrome oxidase subunit I (COI) gene using polymerase chain reaction and direct sequencing. Clustering analysis was carried out by constructing a phylogenetic tree to determine the genetic variation and diversity of local Haemaphysalis ticks. Based on external morphological characterizations, all immature ticks were successfully identified down to the genus level only. Molecular analysis of the genotypic using COI gene revealed 16 individuals (84%) as Haemaphysalis hystricis, and three individuals as H. humerosa with sequence homology of 97-99 and 86-87%, respectively. Haemaphysalis hystricis were clustered in their respective monophyletic group in the phylogeny trees with a bootstrap of 100%. Furthermore, a low intraspecific variation (<0.3%) was observed among Malaysian H. hystricis but high interspecific value (>15%) recorded. This study morphologically and molecularly confirms the presence of H. hystricis in Malaysia and the findings will add value to the existing knowledge in identification of ticks in this country.
Mays, S E; Houston, A E; Trout Fryxell, R T
Amblyomma maculatum Koch (Acari: Ixodidae) is established in western Tennessee, a region with increased risk for Rocky Mountain spotted fever and ehrlichiosis. This tick transmits Rickettsia parkeri to humans, likely contributing to cases of rickettsiosis in the region. The objective was to determine pathogen associations within questing and host-collected A. maculatum, and identify ecological factors associated with pathogen infection that may increase the effectiveness of surveillance methods. Of 265 ticks tested, 60 (22.6%) were infected with R. parkeri, and 15 (5.7%) with Candidatus Rickettsia andeanae, a Rickettsia of unknown pathogenicity. Two deer-collected ticks tested positive for Ehrlichia ewingii. No ticks were positive for Anaplasma or Borrelia species. None of the ecological factors tested (collection month, collection source, sex, and habitat type) were associated with R. parkeri infection. This project developed baseline prevalence and incidence data for monitoring pathogen prevalence in A. maculatum populations, and identified an inexpensive method for distinguishing R. parkeri from Ca. R. andeanae.
Hope, Michelle; Menzies, Moira; Kemp, David
The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Acari: Ixodidae), is a major vector of tick fever organisms affecting cattle in many parts of the world, including Australia, Africa, and South America. Control of the southern cattle tick through acaricide use is an important approach in disease management. Resistance has emerged to many of the acaricides currently and previously used, including the cyclodienes. Although cyclodiene resistance mechanisms have been characterized in many insect species, this report is the first to identify mutations associated with dieldrin resistance in the cattle tick. A novel two base pair mutation in the GABA-gated chloride channel gene has been identified at position 868-9 and causes a codon change from threonine to leucine. Analysis of a small number of field-collected samples resistant to dieldrin shows this mutation has been maintained without selection pressure since the withdrawal of dieldrin in Australia > 20 yr ago. The mutation is not found in other laboratory-maintained strains of R. microplus that were subject to selection pressure with various acaricides.
Bowen, C J; Jaworski, D C; Wasala, N B; Coons, L B
Amblyomma americanum (L.) ticks continue to emerge as disease vectors in many areas of the United States. Tick macrophage migration inhibitory factor (MIF) was first identified in A. americanum females and has been demonstrated to inhibit macrophage movement to the same extent as human MIF. This study was conducted to further characterize and elucidate the physiological role for MIF in tick feeding. A relative quantitative PCR assay was developed to determine the level of MIF gene expression during tick feeding. In addition, RNAi techniques were used to silence MIF prior to blood feeding. Physiological parameters of tick engorgement weight, length of feeding interval, and egg masses were observed to check for phenotypic manifestations of RNA silencing. Specific tick MIF antibody was used to localize MIF protein in frozen tick tissue sections. Tissue specific gene expression indicated that the midgut tissues were the most highly enriched for the MIF. Levels of gene expression did not parallel MIF protein pools seen in tissue sections. Of particular importance was the finding that unfed tick salivary glands appear to contain vesicles that are specific for MIF protein. This is the first demonstration of a pool of MIF that could be secreted during the first hours of tick feeding. While MIF silencing was demonstrated at the molecular level, no physiological phenotype was apparent. The MIF protein pools already available in the tissues may be sufficient to accomplish female tick feeding. Our studies show that the most prominent source of MIF during tick feeding is the midgut tissue. Future studies will address the role of MIF in blood feeding and nutrient digestion in the immature life stages of the tick.
Schulze, T L; Jordan, R A; Hung, R W; Taylor, R C; Markowski, D; Chomsky, M S
A single barrier application of granular deltamethrin to the woodland edges of a forested residential community in late spring significantly reduced the abundance of Ixodes scapularis Say nymphs. The application also suppressed the population of Amblyomma americanum (L.) nymphs, which recently became established in the study area. The efficacy of deltamethrin is compared with other commonly used acaricides.
Greay, Telleasha L; Oskam, Charlotte L; Gofton, Alexander W; Rees, Robert L; Ryan, Una M; Irwin, Peter J
Ticks are among the most important vectors of pathogens affecting companion animals, and also cause health problems such as tick paralysis, anaemia, dermatitis, and secondary infections. Twenty ixodid species have previously been recorded on dogs, cats, and horses in Australia, including Rhipicephalus sanguineus, Ixodes holocyclus and Haemaphysalis longicornis, which transmit tick-borne diseases. A survey of hard ticks (Acari: Ixodidae) was conducted during 2012-2015 to investigate tick species that infest dogs, cats, and horses in Australia. Individual tick specimens were collected from dogs, cats and horses across Australia and sample collection locations were mapped using QGIS software. Ticks were morphologically examined to determine species, instar and sex. The companion animal owners responded to questionnaires and data collected were summarised with SPSS software. A total of 4765 individual ticks were identified in this study from 7/8 states and territories in Australia. Overall, 220 larvae, 805 nymphs, 1404 males, and 2336 females of 11 tick species were identified from 837 companion animal hosts. One novel host record was obtained during this study for Ixodes myrmecobii, which was found on Felis catus (domestic cat) in the town of Esperance, Western Australia. The most common tick species identified included R. sanguineus on dogs (73 %), I. holocyclus on cats (81 %) and H. longicornis on horses (60 %). This study is the first of its kind to be conducted in Australia and our results contribute to the understanding of the species and distribution of ticks that parasitise dogs, cats, and horses in Australia. Records of R. sanguineus outside of the recorded distribution range emphasise the need for a systematic study of the habitat range of this species. Several incomplete descriptions of ixodid species encountered in this study hindered morphological identification.
Caetano, Rebecca Leal; Vizzoni, Vinicius Figueiredo; Bitencourth, Karla; Carriço, Cesar; Sato, Tayra Pereira; Pinto, Zeneida Teixeira; De Oliveira, Stefan Vilges; Amorim, Marinete; Voloch, Carolina Moreira; Gazeta, Gilberto Salles
The Rhipicephalus sanguineus (Latreille) complex (Acari:Ixodidae) is composed of species with intra- and interspecific morphological variation that make their diagnosis difficult. In the present study, male specimens of the R. sanguineus complex were collected from dogs in six districts of three regions of Brazil and submitted to molecular and scanning electron microscopy (SEM) analyses. Analysis of COX1 gene, 12S rDNA, and D-loop rDNA shows that ticks classified as R. sanguineus form two different clades. Morphological comparisons using SEM found adult males to exhibit morphological differences in Haller's organ, festoons, and adanal, spiracular, and genital plates, with the last having potential usefulness in distinguishing male specimens of the complex. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.
Li, Andrew Y; Davey, Ronald B; Miller, Robert J; Guerrero, Felix D; George, John E
The Santa Luiza strain of the southern cattle tick, Boophilus microplus (Canestrini) (Acari: Ixodidae), is resistant to both permethrin and amitraz. A study was conducted at the USDA Cattle Fever Tick Research Laboratory in Texas to investigate the genetic basis of permethrin resistance with cross-mating experiments, and to determine the mechanisms of permethrin resistance through synergist bioassays and biochemical analysis of esterase profiles. The Muñoz strain, an acaricide-susceptible reference strain, was used as the susceptible parent and the Santa Luiza strain, originating in Brazil, was used as the resistant parent. The Food and Agriculture Organization larval packet test was used to measure the levels of susceptibility of larvae of the parental strains, F1, backcross, F2, and F3 generations to permethrin. Results of reciprocal crossing experiments suggested that permethrin resistance was inherited as an incomplete recessive trait. There was no significant maternal effect on larval progeny's susceptibility to permethrin in the F1 and subsequent generations. The values of the degree of dominance were estimated at -0.700 and -0.522 for the F1 larvae with resistant and susceptible female parents, respectively. Results of bioassays on larval progeny of the F1 backcrossed with the resistant parent strain and of the F2 generations suggested that one major gene was responsible for permethrin resistance in the Santa Luiza strain. Selection of F3 larvae with either permethrin or amitraz led to significantly increased resistance to both permethrin and amitraz, indicating a close linkage between genes responsible for permethrin and amitraz resistance. The possible involvement of metabolic enzymes in permethrin resistance in the Santa Luiza strain of B. microplus was dismissed by the lack of enhanced synergism by TPP or PBO, as observed in synergist bioassays, as well as by the lack of enhanced esterase activity in the Santa Luiza strain relative to the susceptible
Reeves, Will K; Durden, Lance A; Dasch, Gregory A
Adults and nymphs of Amblyomma exornatum Koch (Acari: Ixodidae), an exotic African tick of monitor lizards, were collected from a Gray's monitor lizard, Varanus olivaceus Hallowell, that died in a reptile facility in Alabama. Nine adult ticks were tested by polymerase chain reaction for rickettsial agents. DNA from a novel spotted fever group Rickettsia was amplified and sequenced from one of the nine ticks. The novel Rickettsia was most similar to "Rickettsia anan," which is associated with Amblyomma from Asia. The detection of a spotted fever group Rickettsia in exotic ticks emphasizes the potential threat posed by the importation and propagation of exotic animals in the United States.
Wright, S A; Tucker, J R; Donohue, A M; Castro, M B; Kelley, K L; Novak, M G; Macedo, P A
Larval and nymphal western blacklegged tick, Ixodes pacificus Cooley & Kohls (Acari: Ixodidae), were collected from birds, rodents, and lizards at Quail Ridge Reserve located in Napa County in northwestern California. Species from three vertebrate classes were sampled simultaneously from two transects during two consecutive spring seasons. Feeding larval and nymphal ticks were removed and preserved for counting, examination and testing for the presence of Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner. Mean infestations with I. pacificus subadults on lizards were 10.0, on birds 2.9, and on rodents 1.3. I. pacificus larvae (204) collected from 10 avian species and (215) collected from two rodent species were tested for the presence of B. burgdorferi s.s. via real-time polymerase chain reaction. Three B. burgdorferi-infected larvae were taken from two Junco hyemalis and two infected larvae from one Neotoma fuscipes Baird. This is the detection of B. burgdorferi ss in an Ixodes pacificus larvae feeding on a Junco hyemalis L., [corrected] in western North America.
The problem of the unnatural transfer of exotic ticks (Acari: Ixodida) on reptiles (Reptilia) imported to Poland is presented. In the period from 2003 to 2007, 382 specimens of reptiles belonging to the following genera were investigated: Testudo, Iguana, Varanus, Gongylophis, Python, Spalerosophis, Psammophis. The reptiles most infested with ticks are imported to Poland from Ghana in Africa, and are the commonly bred terrarium reptiles: Varanus exanthematicus and Python regius. As a result of the investigations, the transfer of exotic ticks on reptiles to Poland was confirmed. There were 2104 specimens of the genera Amblyomma and Hyalomma. The following species were found: Amblyomma exornatum Koch, 1844, Amblyomma flavomaculatum (Lucas, 1846), Amblyomma latum Koch, 1844, Amblyomma nuttalli Donitz, 1909, Amblyomma quadricavum (Schulze, 1941), Amblyomma transversale (Lucas, 1844), Amblyomma varanense (Supino, 1897), Amblyomma sp. Koch, 1844, Hyalomma aegyptium (Linnaeus, 1758). All the species of ticks of genus Amblyomma revealed have been discovered in Poland for the first time. During the research, 13 cases of anomalies of morphological structure were confirmed in the ticks A. flavomaculatum, A. latum and H. aegyptium. The expanding phenomenon of the import of exotic reptiles in Poland and Central Europe is important for parasitological and epidemiological considerations, and therefore requires monitoring and wide-ranging prophylactic activities to prevent the inflow of exotic parasites to Poland.
Nava, Santiago; Mangold, Atilio J; Mastropaolo, Mariano; Venzal, José M; Oscherov, Elena B; Guglielmone, Alberto A
All parasitic stages of Amblyomma boeroi n. sp. (Acari: Ixodidae) are described here from Catagonus wagneri (Rusconi) in Argentina. The diagnostic characters for the male are a combination of orbited eyes, a 2/2 dental formula, coxa IV considerably larger than coxae I-III and with a long, sickle-shaped, medially directed spur arising from its internal margin, a scutum which is light grey to very pale ivory in colour, and the absence of a postanal groove. The diagnostic characters for the females are a combination of orbited eyes, a central pair and two marginal pairs of short, coarse notal setae, a 2/2 dental formula, and the absence of a postanal groove. The nymph has short palpi and a 2/2 dental formula arranged in 6 rows, its eyes are convex and orbited, and it has no postanal groove. The dorsally rectangular basis capituli of the larva, its bulging eyes and slightly sinuous posterior scutal margin all serve to distinguish it from the larva of other species of the genus. The principal host for all parasitic stages is C. wagneri (Artiodactyla: Tayassuidae). Phylogenetically A. boeroi appears to represent an independent lineage within Amblyomma Koch, 1844.
Dantas-Torres, Filipe; Giannelli, Alessio; Figueredo, Luciana Aguiar; Otranto, Domenico
The widespread geographical distribution of the brown dog tick Rhipicephalus sanguineus (Acari: Ixodidae) is related to the cosmopolitan distribution of its primary host and to its adaptability to different environments, under variable climate conditions. Field studies have suggested that temperature is the most important factor driving the population dynamics of this tick species. In order to investigate the effects of prolonged exposure to low temperature on eggs of R. sanguineus, nine groups (II-X) of five egg batches each were maintained at 8+/-2 degrees C (70+/-10% RH, and scotophase) for 15, 30, 45, 60, 75, 90, 105, 120, and 135 days. One group (group I) was maintained in the incubator (26+/-1 degrees C, 70+/-10% RH, and scotophase) and used as control. The mean egg incubation period from group I was 11.6+/-0.5 days, with an egg hatch rate of 99.5+/-0.5%. Conversely, no egg hatched at 8 degrees C. Exposure to cold showed a strong positive correlation with egg incubation period (r=0.99) as well as a strong negative correlation with egg hatch rate (r=-0.95) and larval longevity (r=-0.99). Overall, the present results points out that R. sanguineus eggs are sensible to prolonged exposure to low temperature, which is definitely a major limiting factor for the establishment of populations of this tick in cold temperate regions. Copyright 2010 Elsevier B.V. All rights reserved.
Che Lah, Ernieenor Faraliana; Yaakop, Salmah; Ahamad, Mariana; Md Nor, Shukor
Abstract Blood meal analysis (BMA) from ticks allows for the identification of natural hosts of ticks (Acari: Ixodidae). The aim of this study is to identify the blood meal sources of field collected on-host ticks using PCR analysis. DNA of four genera of ticks was isolated and their cytochrome b (Cyt b) gene was amplified to identify host blood meals. A phylogenetic tree was constructed based on data of Cyt b sequences using Neighbor Joining (NJ) and Maximum Parsimony (MP) analysis using MEGA 5.05 for the clustering of hosts of tick species. Twenty out of 27 samples showed maximum similarity (99%) with GenBank sequences through a Basic Local Alignment Search Tool (BLAST) while 7 samples only showed a similarity range of between 91–98%. The phylogenetic trees showed that the blood meal samples were derived from small rodents (Leopoldamys sabanus, Rattus tiomanicus and Sundamys muelleri), shrews (Tupaia glis) and mammals (Tapirus indicus and Prionailurus bengalensis), supported by 82–88% bootstrap values. In this study, Cyt b gene as a molecular target produced reliable results and was very significant for the effective identification of ticks’ blood meal. The assay can be used as a tool for identifying unknown blood meals of field collected on-host ticks. PMID:25685009
Springer, Yuri P; Jarnevich, Catherine S.; Barnett, David T.; Monaghan, Andrew J.; Eisen, Rebecca J
The Lone star tick (Amblyomma americanum L.) is the primary vector for pathogens of significant public health importance in North America, yet relatively little is known about its current and potential future distribution. Building on a published summary of tick collection records, we used an ensemble modeling approach to predict the present-day and future distribution of climatically suitable habitat for establishment of the Lone star tick within the continental United States. Of the nine climatic predictor variables included in our five present-day models, average vapor pressure in July was by far the most important determinant of suitable habitat. The present-day ensemble model predicted an essentially contiguous distribution of suitable habitat extending to the Atlantic coast east of the 100th western meridian and south of the 40th northern parallel, but excluding a high elevation region associated with the Appalachian Mountains. Future ensemble predictions for 2061–2080 forecasted a stable western range limit, northward expansion of suitable habitat into the Upper Midwest and western Pennsylvania, and range contraction along portions of the Gulf coast and the lower Mississippi river valley. These findings are informative for raising awareness of A. americanum-transmitted pathogens in areas where the Lone Star tick has recently or may become established.
Springer, Yuri P.; Jarnevich, Catherine S.; Barnett, David T.; Monaghan, Andrew J.; Eisen, Rebecca J.
The Lone star tick (Amblyomma americanum L.) is the primary vector for pathogens of significant public health importance in North America, yet relatively little is known about its current and potential future distribution. Building on a published summary of tick collection records, we used an ensemble modeling approach to predict the present-day and future distribution of climatically suitable habitat for establishment of the Lone star tick within the continental United States. Of the nine climatic predictor variables included in our five present-day models, average vapor pressure in July was by far the most important determinant of suitable habitat. The present-day ensemble model predicted an essentially contiguous distribution of suitable habitat extending to the Atlantic coast east of the 100th western meridian and south of the 40th northern parallel, but excluding a high elevation region associated with the Appalachian Mountains. Future ensemble predictions for 2061–2080 forecasted a stable western range limit, northward expansion of suitable habitat into the Upper Midwest and western Pennsylvania, and range contraction along portions of the Gulf coast and the lower Mississippi river valley. These findings are informative for raising awareness of A. americanum-transmitted pathogens in areas where the Lone Star tick has recently or may become established. PMID:26217042
Borges, L M; Labruna, M B; Linardi, P M; Ribeiro, M F
We report on an evaluation of the systematic position of the tick Anocentor nitens (Neumann), examining particularly whether Anocentor should be regarded as a subgenus of Dermacentor or as a separate genus. Twelve species of Ixodidae were analyzed phenetically by using 24 characters of adult ticks. A phenogram indicated 3 clusters, with Anocentor more closely related to Rhipicephalus than to Dermacentor. The results of this study endorse the validity of the monotypic genus Anocentor.
The brown dog tick can be a serious residential pest due to its unique ability, among ticks, to complete its lifecycle indoors. A single engorged and fertilized female tick can oviposit around 4,000 eggs, allowing indoor establishment to be rapid and easy to miss in early-stage infestations. Acari...
Nchu, F; Maniania, N K; Touré, A; Hassanali, A; Eloff, J N
Experiments were conducted to explore the use of a semiochemical bait to enhance exposure of Amblyomma variegatum Fabricius (Acari: Ixodidae) to different formulations of the entomopathogenic fungus Metarhizium anisopliae (Metsch.) Sorok. (Ascomycota: Hypocreales). Initially, the relative efficacies of attraction-aggregation-attachment pheromone (AAAP), made up of o-nitrophenol, methyl salicylate and nonanoic acid in the ratio 2:1:8, 1-octen-3-ol and butyric acid, were evaluated in an olfactometer. Only AAAP and 1-octen-3-ol were found to elicit attractive responses to the tick. Simultaneous release of 1-octen-3-ol and AAAP together with CO(2) from a trap in semifield plots attracted up to 94.0+/-6% of adult ticks from a distance of 6m, and up to 24.0+/-5.1% from 8m. Formulations of M. anisopliae (dry powder, oil, and emulsifiable) applied within the trap baited with AAAP, 1-octen-3-ol and CO(2) resulted in high levels of contamination of the ticks attracted to the traps. However, 48h after autoinoculation, 89.1 and 33.3% of conidia were lost in dry powder and oil formulations, respectively. Emulsifiable formulation showed least loss of propagules (17.1%). Samples of ticks attracted to the baited traps were transferred to plastic basins containing grass and maintained for 5 weeks. The experiment was conducted in rainy and dry seasons. Emulsifiable formulation gave the highest relative tick reduction in both seasons: 54.7 and 46.5% in rainy and dry seasons, respectively, followed by oil formulation (32.0 and 23.8%) and powder formulation (38.0 and 24.4%).
Johnson, Tammi L; Graham, Christine B; Boegler, Karen A; Cherry, Cara C; Maes, Sarah E; Pilgard, Mark A; Hojgaard, Andrias; Buttke, Danielle E; Eisen, Rebecca J
Tick-borne pathogens transmitted by Ixodes scapularis Say (Acari: Ixodidae), also known as the deer tick or blacklegged tick, are increasing in incidence and geographic distribution in the United States. We examined the risk of tick-borne disease exposure in 9 national parks across six Northeastern and Mid-Atlantic States and the District of Columbia in 2014 and 2015. To assess the recreational risk to park visitors, we sampled for ticks along frequently used trails and calculated the density of I. scapularis nymphs (DON) and the density of infected nymphs (DIN). We determined the nymphal infection prevalence of I. scapularis with a suite of tick-borne pathogens including Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia microti. Ixodes scapularis nymphs were found in all national park units; DON ranged from 0.40 to 13.73 nymphs per 100 m2. Borrelia burgdorferi, the causative agent of Lyme disease, was found at all sites where I. scapularis was documented; DIN with B. burgdorferi ranged from 0.06 to 5.71 nymphs per 100 m2. Borrelia miyamotoi and A. phagocytophilum were documented at 60% and 70% of the parks, respectively, while Ba. microti occurred at just 20% of the parks. Ixodes scapularis is well established across much of the Northeastern and Mid-Atlantic States, and our results are generally consistent with previous studies conducted near the areas we sampled. Newly established I. scapularis populations were documented in two locations: Washington, D.C. (Rock Creek Park) and Greene County, Virginia (Shenandoah National Park). This research demonstrates the potential risk of tick-borne pathogen exposure in national parks and can be used to educate park visitors about the importance of preventative actions to minimize tick exposure. 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.
Ogrzewalska, Maria; Nieri-Bastos, Fernanda A; Marcili, Arlei; Nava, Santiago; González-Acuña, Daniel; Muñoz-Leal, Sebastián; Ruiz-Arrondo, Ignacio; Venzal, José M; Mangold, Atilio; Labruna, Marcelo B
The tick Amblyomma parvitarsum (Acari: Ixodidae) has established populations in Andean and Patagonic environments of South America. For the present study, adults of A. parvitarsum were collected in highland areas (elevation >3500 m) of Argentina and Chile during 2009-2013, and tested by PCR for rickettsial infection in the laboratory, and isolation of rickettsiae in Vero cell culture by the shell vial technique. Overall, 51 (62.2%) out of 82 A. parvitarsum adult ticks were infected by spotted fever group (SFG) rickettsiae, which generated DNA sequences 100% identical to each other, and when submitted to BLAST analysis, they were 99.3% identical to corresponding sequence of the ompA gene of Rickettsia sp. strain Atlantic rainforest. Rickettsiae were successfully isolated in Vero cell culture from two ticks, one from Argentina and one from Chile. DNA extracted from the third passage of the isolates of Argentina and Chile were processed by PCR, resulting in partial sequences for three rickettsial genes (gltA, ompB, ompA). These sequences were concatenated and aligned with rickettsial corresponding sequences available in GenBank. Phylogenetic analysis revealed that the A. pavitarsum rickettsial agent grouped under high bootstrap support in a clade composed by the SFG pathogens R. sibirica, R. africae, R. parkeri, Rickettsia sp. strain Atlantic rainforest, and two unnamed SFG agents of unknown pathogenicty, Rickettsia sp. strain NOD, and Rickettsia sp. strain ApPR. The pathogenic role of this A. parvitarsum rickettsia cannot be discarded, since several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections.
Vázquez, Luís; Panadero, Rosario; Dacal, Vicente; Pato, Francisco Javier; López, Ceferino; Díaz, Pablo; Arias, María Sol; Fernández, Gonzalo; Díez-Baños, Pablo; Morrondo, Patrocinio
During the 2007 and 2008 hunting seasons (April-October) the skin of 367 roe deer (Capreolus capreolus L.), hunted in different preserves from Galicia (Northwestern Spain), were examined for ticks (Acari: Ixodidae). The overall prevalence of infestation by ticks was 83.1%. The predominant species was Ixodes ricinus (83.1%), whereas a single Dermacentor marginatus specimen appeared in one roe deer. All developmental stages of I. ricinus were found parasitizing roe deer, the adults being the most frequent (82.2%), followed by nymphs (45.6%) and larvae (27.2%). The mean intensity of infestation by I. ricinus was 43.2 ± 49.85; most of them were adults (30.7 ± 31.64) and in a lesser extend nymphs (16.9 ± 24.74) and larvae (10.7 ± 29.90). Ixodes ricinus was present all over the study with percentages that oscillated between 100% in spring and 57.4% in autumn. CHAID algorithm showed the sex of roe deer as the most influential factor in tick prevalence, followed by the climatic area. The different developmental stages of I. ricinus were more frequent in males than in females, and the prevalence of adults and larvae were higher in roe deer from coastal areas than in those from mountainous and central areas, whereas nymphs were more frequent in mountainous areas. Host age and density were not determinants for tick infestation. Our results confirm that roe deer are important hosts for I. ricinus in northwestern Spain, serving as a vehicle for the geographic distribution of these ticks.
Nava, Santiago; Mastropaolo, Mariano; Mangold, Atilio J; Martins, Thiago F; Venzal, José M; Guglielmone, Alberto A
All stages of Amblyomma hadanii n. sp. (Acari: Ixodidae) are described from northwestern Argentina. The diagnostic characters for males are a combination of the pattern of scutal ornamentation, basis capituli dorsally rectangular with cornua, coxa I with two subequal spurs (the internal wider, the external longer), coxae II-III with a single spur, coxa IV with a single spur not reaching level of anus, ventral plates irregular in shape (larger and sometimes with a small incision on festoons 4, 5 and 6) and hypostome spatulate with dental formula 3/3 in 7-8 rows. The diagnostic characters for the females are a combination of scutal ornamentation, postero-lateral margins of scutum slightly convex, coxa I with two subequal spurs (the internal wider, the external longer), basis capituli dorsally rectangular, porose areas rounded, genital aperture U-shaped, and hypostome spatulate with dental formula 3/3 in 7-8 rows. Diagnosis of nymphs can be performed by a combination of basis capituli rectangular, scutum with large punctations in the lateral fields and small punctations in the central field, and cervical groove short and ending as a small shallow depression at the eye level. Larvae are diagnosed by the shape of basis capituli, scutum with with posterior margin slightly convex, and legs with coxa I with 2 triangular spur (the external longer than the internal), and with coxae II and III each with 1 triangular spur. The hosts recorded for this new tick species are Tapirus terrestris (Linnaeus), horse, cattle, dog and humans. Analyses of a 410 bp fragment of the mitochondrial 16S rRNA gene and the complete sequence of the nuclear 18S rRNA gene supported the description of A. hadanii as a new species.
Nava, S; Szabó, M P J; Mangold, A J; Guglielmone, A A
The hosts, distribution, intraspecific genetic variation and phylogenetic position of Amblyomma parvum (Acari: Ixodidae) have recently been re-assessed. Data on this tick's hosts and distribution were obtained not only from existing literature but also from unpublished records. Sequences of the ticks' mitochondrial 16S ribosomal DNA (rDNA) were used to evaluate genetic variation among specimens of A. parvum from different localities in Argentina and Brazil, and to explore the phylogenetic relationships between this tick and other Amblyomma species. Although several species of domestic and wild mammal act as hosts for adult A. parvum, most collected adults of this species have come from cattle and goats. Caviid rodents of the subfamily Caviinae appear to be the hosts for the immature stages. So far, A. parvum has been detected in 12 Neotropical biogeographical provinces (Chaco, Cerrado, Eastern Central America, Venezuelan Coast, Pantanal, Parana Forest, Caatinga, Chiapas, Venezuelan Llanos, Monte, Western Panamanian Isthmus, and Roraima) but the Chaco province has provided significantly more specimens than any other (P<0.0001). The 16S rDNA sequences showed just 0.0%-1.1% divergence among the Argentinean A. parvum investigated and no more than 0.2% divergence among the Brazilian specimens. The observed divergence between the Argentinean and Brazilian specimens was, however, greater (3.0%-3.7%). Although there is now molecular and morphological evidence to indicate that A. parvum, A. pseudoparvum, A. auricularium and A. pseudoconcolor are members of a natural group, previous subgeneric classifications do not reflect this grouping. The subgeneric status of these tick species therefore needs to be re-evaluated. The 16S-rDNA-based evaluation of divergence indicates that the gene flow between Argentinean and Brazilian 'A. parvum' is very limited and that the Argentinean 'A. parvum' may be a different species to the Brazilian.
Brillhart, D B; Fox, L B; Upton, S J
Seven species of hard-bodied ticks were collected from 20 species of small and medium-sized mammals in Kansas; Amblyomma americanum L., Dermacentor variabilis (Say), Haemaphysalis leporispalustris (Packard), Ixodes cookei Packard, I. kingi Bishopp, I. sculptus Neumann, and I. texanus Banks. Dermacentor variabilis was found statewide, A. americanum only in the eastern one-third of the state, and the Ixodes spp. and H. leporispalustris were widely scattered. The most common tick found was D. variabilis, both by itself and in association with other ticks. Mammals that ticks were collected from included Canis latrans Say, Cynomys ludovicianus ludovicianus (Ord), Didelphis virginianus Kerr, Geomys bursarius (Shaw), Lynx rufus (Schreber), Marmota monax bunkeri Black, Mephitis mephitis (Schreber), Microtus ochrogaster (Wagner), Mus musculus L., Peromyscus leucopus (Rafinesque), P. maniculatus (Wagner), Procyon lotor hirtus Nelson and Goldman, Reithrodontomys megalotis (Baird), Sciurus niger rufiventer Geoffroy, Sigmodon hispidus texianus (Audubon and Bachman), Sylvilagus floridanus (J. A. Allen), Taxidea taxus taxus (Schreber), and Vulpes velox velox (Say).
Yunik, Matthew E.M.; Galloway, Terry D.; Lindsay, L. Robbin
Bovine anaplasmosis is the disease caused by the bacterium Anaplasma marginale. It can cause production loss and death in cattle and bison. This was a reportable disease in Canada until April 2014. Before then, infected herds were quarantined and culled, removing infected animals. In North America, A. marginale is biologically vectored by hard ticks (Acari: Ixodidae), Dermacentor variabilis and D. andersoni. Biting flies, particularly horse flies (Diptera: Tabanidae), can also act as mechanical vectors. An outbreak of bovine anaplasmosis, consisting of 14 herds, was detected in southern Manitoba in 2008. This outbreak lasted multiple rounds of testing and culling before eradication in 2011, suggesting local maintenance of the pathogen was occurring. We applied novel approaches to examine the vector ecology of this disease in this region. We did not detect A. marginale by screening of 2056 D. variabilis (2011 and 2012) and 520 horse flies (2011) using polymerase chain reaction (PCR). PMID:27127345
Apanaskevich, Dmitry A
Recent reexamination of collection lots stored in the United States National Tick Collection revealed adult specimens of Dermacentor compactus Neumann, 1901 (Acari: Ixodidae) reared from field-collected nymphs, which allowed us to associate field-collected unidentified nymphs and larvae with this species. Nymphs of D. compactus can be easily distinguished from those of other congeneric species by the shape of the scutum and spiracular plate, the hypostome dentition, and the size of the spurs on the coxae. Larvae of this species can be distinguished by the shape and sculpture of the scutum, the shape of basis capituli, the absence of auriculae, and the size of the spurs on coxae II and III. Both nymphs and larvae feed mostly on various species of squirrels (Rodentia: Sciuridae). Considerably fewer nymphs and larvae were found on murid rodents (Rodentia: Muridae), domestic dogs (Carnivora: Canidae), and a snake (Squamata: Colubridae).
Koc, Samed; Oz, Emre; Cinbilgel, Ilker; Aydin, Levent; Cetin, Huseyin
The acaricidal activity of an essential oil obtained from aerial parts of Origanum bilgeri P.H. Davis (Lamiaceae), an endemic species in Turkey, and its major constituents, carvacrol was evaluated against unfed adults Rhipicephalus turanicus Pomerantzev (Acari: Ixodidae) collected from Kepez, Antalya. The composition of the essential oil was analyzed by GC/MS. The major compound identified in the oil was carvacrol (93.02%). Generally, tick mortalities to the O. bilgeri distillate and carvacrol increased with concentrations. O. bilgeri oil produced >83% mortality at 48h at a concentration of 0.8% and mortality was higher than 63% at a carvacrol concentration of 0.4%. Our results have shown that O. bilgeri essential oil and its major component, carvacrol, may have potential as acaricidal agents against R. turanicus.
Yunik, Matthew E M; Galloway, Terry D; Lindsay, L Robbin
Bovine anaplasmosis is the disease caused by the bacterium Anaplasma marginale. It can cause production loss and death in cattle and bison. This was a reportable disease in Canada until April 2014. Before then, infected herds were quarantined and culled, removing infected animals. In North America, A. marginale is biologically vectored by hard ticks (Acari: Ixodidae), Dermacentor variabilis and D. andersoni. Biting flies, particularly horse flies (Diptera: Tabanidae), can also act as mechanical vectors. An outbreak of bovine anaplasmosis, consisting of 14 herds, was detected in southern Manitoba in 2008. This outbreak lasted multiple rounds of testing and culling before eradication in 2011, suggesting local maintenance of the pathogen was occurring. We applied novel approaches to examine the vector ecology of this disease in this region. We did not detect A. marginale by screening of 2056 D. variabilis (2011 and 2012) and 520 horse flies (2011) using polymerase chain reaction (PCR).
Abdigoudarzi, M; Esmaeilnia, K; Shariat, N
Chemical control method using different acaricides as spray, dipping solution or pour-on is routinely used for controlling ticks. Biological control agents are favorable due to their safety for animals and environment. Entomopathogenic fungi such as Beauveria bassiana are well known for controlling ticks. In this study, two Iranian indigenous strains of B. bassiana (B. bassiana 5197 and B. bassiana Evin) were selected and grown on specific media. The pathogenic effects of these strains were evaluated on adult stages of two Iranian Ixodidae members (H. anatolicum anatolicum Koch 1844, and H. marginatum Koch 1844) by dipping method. Two Iranian strains of Beauveria bassiana (Beauveria bassiana 5197 and Beauveria bassiana Evin) were selected and were grown successfully on specific media. The pathogenic effects of these strains were evaluated on adult stages of Iranian Ixodidae members such as, Hyalomma anatolicum anatolicum and H. marginatum by dipping method (these ticks were grown up at laboratory conditions during 2002 up to 2003 and still it is continued) . There was no effect of strain 5197 on mortality or fecundity rates for ticks. There was acute phase sign of paralysis in test group after dipping ticks in suspension made from Evin strain of B. bassiana. In addition, the test groups were totally died after four months, but the control groups survived for six months. High concentration of fungal spores is needed for inducing fungal infection. Additional study using different strains and fungi on Iranian ticks is proposed.
Abdigoudarzi, M; Esmaeilnia, K; Shariat, N
Background: Chemical control method using different acaricides as spray, dipping solution or pour-on is routinely used for controlling ticks. Biological control agents are favorable due to their safety for animals and environment. Entomopathogenic fungi such as Beauveria bassiana are well known for controlling ticks. In this study, two Iranian indigenous strains of B. bassiana (B. bassiana 5197 and B. bassiana Evin) were selected and grown on specific media. The pathogenic effects of these strains were evaluated on adult stages of two Iranian Ixodidae members (H. anatolicum anatolicum Koch 1844, and H. marginatum Koch 1844) by dipping method. Methods: Two Iranian strains of Beauveria bassiana (Beauveria bassiana 5197 and Beauveria bassiana Evin) were selected and were grown successfully on specific media. The pathogenic effects of these strains were evaluated on adult stages of Iranian Ixodidae members such as, Hyalomma anatolicum anatolicum and H. marginatum by dipping method (these ticks were grown up at laboratory conditions during 2002 up to 2003 and still it is continued) . Results: There was no effect of strain 5197 on mortality or fecundity rates for ticks. There was acute phase sign of paralysis in test group after dipping ticks in suspension made from Evin strain of B. bassiana. In addition, the test groups were totally died after four months, but the control groups survived for six months. Conclusion: High concentration of fungal spores is needed for inducing fungal infection. Additional study using different strains and fungi on Iranian ticks is proposed. PMID:22808380
Blanco, Carolina Moreira; Teixeira, Bernardo Rodrigues; da Silva, Alexandro Guterres; de Oliveira, Renata Carvalho; Strecht, Liana; Ogrzewalska, Maria; de Lemos, Elba Regina S
Information about tick fauna and monitoring of pathogen prevalences in ticks (Acari: Ixodidae) in various habitat types can enhance knowledge about the epidemiology of tick-borne pathogens in Brazil. This work shows the results of a study of tick parasitism of wild rodents and marsupials collected in seven localities in the southern part of Brazil, within Atlantic Forest and Cerrado biomes. A total of 61 ticks were collected from small mammals, and after identification to the species level, the ticks were individually tested for the presence of bacteria of the genera Rickettsia, Borrelia, family Anaplasmataceae, and protozoa of the genus Babesia. The following species of ticks were found: Amblyomma ovale Koch, 1844, Amblyomma dubitatum Neumann, 1899, Amblyomma fuscum Neumann, 1907, Ixodes aragaoi Fonseca, 1935, Ixodes fuscipes Koch, 1844, Ixodes loricatus Neumann, 1899, and Ixodes schulzei Aragão and Fonseca, 1951. Among tested ticks, no DNA of Borrelia, Babesia or Anaplasmataceae was detected. Two nymphs of A. ovale were found infected with Rickettsia bellii and four nymphs of I. aragaoi with Rickettsia sp., genetically close to Rickettsia monacensis, Rickettsia tamurae and the endosymbiont Rickettsia spp., previously found in various Ixodidae. In one nymph of A. fuscum, DNA of a novel Hepatozoon sp. was found. Additionally we provide novel tick-host associations.
Durden, L A; Oliver, J H; Kinsey, A A
From September 1997 through July 1999, 300 individuals and 46 species of birds were mist-netted and screened for ticks and spirochetes on St. Catherine's Island, Liberty County, GA. Seventy-six (25%) of the birds were parasitized by a meal intensity of 4.6 ticks. Seasonally, more birds were infested with ticks during the summer (50% in 1998, 34% in 1999) than in spring (15% in 1998, 11% in 1999) or fall (21% in 1997, 20% in 1998), mainly because of severe infestations on some birds by immature stages of the lone star tick, Amblyomma americanum (L.), during this season. Eight species ofticks were recovered from 14 species of birds during this study: A. americanum (74 nymphs, 168 larvae); the blacklegged tick, Ixodes scapularis Say (11 nymphs, 28 larvae), the Gulf Coast tick, Amblyomma maculatum Koch (two nymphs, 29 larvae); Ixodes minor Neumann (16 larvae); the rabbit tick. Haemaphysalis leporispalustris (Packard) (one nymph, 14 larvae); the bird tick Ixodes brunneus Koch (two larvae); the American dog tick, Dermacentor variabilis (Say) (one nymph); and Ixodes affinis Neumann (one larva). The Carolina wren was parasitized by more species of ticks (seven) than any other bird species, followed by the northern cardinal (five), white-throated sparrow (four) and painted bunting (three). Spirochetes were isolated in BSK II medium from one tick (a nymphal A. americanum) and from skin biopsies of 12 (4%) of the individual birds (three downy woodpeckers, three northern waterthrushes, two Carolina wrens, one American redstart, one pine warbler, one Swainson's thrush, and one white-eyed vireo) all in fall 1997. This concentrated phenology of spirochete isolations might reflect periodic amplification or recrudescence of spirochetes in reservoir avian hosts.
Corn, Joseph L; Berger, Patrick; Mertins, James W
Surveys in 2001, 2005, and 2006 attempted to determine the role of wildlife in maintenance and dissemination of the tropical bont tick, Amblyomma variegatum (F.) (Acari: Ixodidae), in St. Croix, U.S. Virgin Islands. Small mammals; birds; white-tailed deer, Odocoileus virginianus (Zimmermann); and feral cattle, Bos taurus L., were examined at nine premises, in mountainous rain forest, and in surrounding areas in western St. Croix, an area including and central to all known bont tick-infested premises on the island. Small Asian mongooses, Herpestes javanicus (E. Geoffroy Saint-Hilaire), yielded 1,566 ectoparasite specimens, representing five species, and including larvae of a soft tick, Carios puertoricensis (Fox); the tropical horse tick, Anocentor nitens (Neumann); and the southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini). Black rats, Rattus rattus L., yielded 144 specimens, representing six ectoparasite species, including C. puertoricensis. Of 25 bird species examined, seven yielded 116 ectoparasite specimens representing at least 14 different species of lice and mites, but no ticks. White-tailed deer and feral cattle yielded only various stages of A. nitens and R. microplus ticks. A. variegatum was not encountered on any potential wildlife host sampled, reflecting its low occurrence in St. Croix during the survey period. One collection of chewing lice (Phthiraptera: Philopteridae) from a spotted sandpiper, Actitis macularia (L.), and collections of feather mites (Acari: Astigmata: Trouessartiidae) from both bananaquits, Coereba flaveola (L.), and black-faced grassquits, Tiaris bicolor (L.), may represent new, undescribed species.
Luo, Jin; Liu, Guang-Yuan; Chen, Ze; Ren, Qiao-Yun; Yin, Hong; Luo, Jian-Xun; Wang, Hui
Hyalomma anatolicum anatolicum (H.a. anatolicum) (Acari: Ixodidae) ticks are globally distributed ectoparasites with veterinary and medical importance. These ticks not only weaken animals by sucking their blood but also transmit different species of parasitic protozoans. Multiple factors influence these parasitic infections including miRNAs, which are non-coding, small regulatory RNA molecules essential for the complex life cycle of parasites. To identify and characterize miRNAs in H.a. anatolicum, we developed an integrative approach combining deep sequencing, bioinformatics and real-time PCR analysis. Here we report the use of this approach to identify miRNA expression, family distribution, and nucleotide characteristics, and discovered novel miRNAs in H.a. anatolicum. The result showed that miR-1-3p, miR-275-3p, and miR-92a were expressed abundantly. There was a strong bias on miRNA, family members, and nucleotide compositions at certain positions in H.a. anatolicum miRNA. Uracil was the dominant nucleotide, particularly at positions 1, 6, 16, and 18, which were located approximately at the beginning, middle, and end of conserved miRNAs. Analysis of the conserved miRNAs indicated that miRNAs in H.a. anatolicum were concentrated along three diverse phylogenetic branches of bilaterians, insects and coelomates. Two possible roles for the use of miRNA in H.a. anatolicum could be presumed based on its parasitic life cycle: to maintain a large category of miRNA families of different animals, and/or to preserve stringent conserved seed regions with active changes in other places of miRNAs mainly in the middle and the end regions. These might help the parasite to undergo its complex life style in different hosts and adapt more readily to the host changes. The present study represents the first large scale characterization of H.a. anatolicum miRNAs, which could further the understanding of the complex biology of this zoonotic parasite, as well as initiate miRNA studies
Gazim, Zilda Cristiani; Demarchi, Izabel Galhardo; Lonardoni, Maria Valdrinez Campana; Amorim, Ana Carolina L; Hovell, Ana Maria C; Rezende, Claudia Moraes; Ferreira, Gilberto Alves; de Lima, Edson Luiz; de Cosmo, Fábio Antunes; Cortez, Diogenes Aparício Garcia
Tetradenia riparia (Lamiaceae) is a well-known herbal medicine with a variety of useful properties, including its acaricidal effect. This experiment was carried out to study the bioacaricidal activity of T. riparia essential oil (EO) against engorged females of Rhipicephalus (Boophilus) microplus (Acari; Ixodidae). For this purpose, nine serial concentrations (12.50%, 6.25%, 3.75%, 1.80%, 0.90%, 0.45%, 0.22%, 0.11%, and 0.056% w/v) of T. riparia were used for the adult immersion test (AIT). For the larval packet test (LPT), we used 14 serial concentrations (100.00%, 50.00%, 25.00%, 12.50%, 6.25%, 3.65%, 1.82%, 0.91%, 0.45%, 0.228%, 0.114%, 0.057%, 0.028%, and 0.014% w/v). The results for AIT showed 100.00% and 2.05% mortality, 19.00 and 90.20% for the total number of eggs, egg-laying inhibition of 0.00% and 90.20%, hatchability inhibition of 0.00% and 70.23%, and product effectiveness of 100.00% and 2.89%, respectively. The AIT indicated that the LC(50) and LC(99.9), calculated using the Probit test, were for mortality (%) 0.534g/mL (0.436-0.632) and 1.552g/mL (1.183-1.92); for total number of eggs were 0.449g/mL (0.339-0.558) and 1.76g/mL (1.27-2.248); and for hatchability inhibition were 0.114g/mL (0.0-0.31) and 2.462g/mL (1.501-3.422), respectively. Larvae between 14 and 21days old were fasted and placed in each envelope. Bioassays were performed at 27°±1°C, RH⩾80%. Larval mortality was observed 24h after treatment and showed 10.60-100% mortality in the LPT bioassay. The LPT showed that the LC(50) and LC(99.9) were 1.222g/mL (0.655-1.788) and 11.382g/mL (7.84-14.91), respectively. A positive correlation between T. riparia EO concentration and tick control, was observed by the strong acaricidal effects against R. (B.) microplus, and the mortality rate of ticks was dose-dependent. Our results showed that T. riparia is a promising candidate as an acaricide against resistant strains of R. (B.) microplus.
The essential oil from Amyris balsamifera (Rutaceae) and elemol, a principal constituent of the essential oil of Osage orange, Maclura pomifera (Moraceae) were evaluated in in vitro and in vivo laboratory bioassays for repellent activity against host-seeking nymphs of the blacklegged tick, Ixodes sc...
The in vitro bioassay is an important tool in repellent discovery and development, with a variety of bioassays used in recent years. Several factors, such as the dimensions and configuration of test surfaces and duration of tick exposure, can influence the outcome of bioassays. We tested two tick re...
Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 in plant defense mechanisms against herbivorous ar- thropods and pathogens (Kappers et al...Thechemical defenses of plants to patho- gens and herbivores . Annu. Rev. Ecol. Syst. 7: 121Ð159. Mixson, T. R., S. R. Campbell, J. S. Gill, H. S
Trout Fryxell, R T; Steelman, C D; Szalanski, A L; Billingsley, P M; Williamson, P C
Rocky Mountain spotted fever (RMSF), caused by the etiological agent Rickettsia rickettsii, is the most severe and frequently reported rickettsial illness in the United States, and is commonly diagnosed throughout the southeast. With the discoveries of Rickettsia parkeri and other spotted fever group rickettsiae (SFGR) in ticks, it remains inconclusive if the cases reported as RMSF are truly caused by R. rickettsii or other SFGR. Arkansas reports one of the highest incidence rates of RMSF in the country; consequently, to identify the rickettsiae in Arkansas, 1,731 ticks, 250 white-tailed deer, and 189 canines were screened by polymerase chain reaction (PCR) for the rickettsial genes gltA, rompB, and ompA. None of the white-tailed deer were positive, while two of the canines (1.1%) and 502 (29.0%) of the ticks were PCR positive. Five different tick species were PCR positive: 244 (37%) Amblyomma americanum L., 130 (38%) Ixodes scapularis Say, 65 (39%) Amblyomma maculatum (Koch), 30 (9%) Rhipicephalus sanguineus Latreille, 7 (4%) Dermacentor variabilis Say, and 26 (44%) unidentified Amblyomma ticks. None of the sequenced products were homologous to R. rickettsii. The most common Rickettsia via rompB amplification was Rickettsia montanensis and nonpathogenic Candidatus Rickettsia amblyommii, whereas with ompA amplification the most common Rickettsia was Ca. R. amblyommii. Many tick specimens collected in northwest Arkansas were PCR positive and these were commonly A. americanum harboring Ca. R. amblyommii, a currently nonpathogenic Rickettsia. Data reported here indicate that pathogenic R. rickettsii was absent from these ticks and suggest by extension that other SFGR are likely the causative agents for Arkansas diagnosed RMSF cases.
Marques, Sandro; Barros-Battesti, Darci Moraes; Faccini, João Luiz Horacio; Onofrio, Valeria Castilho
Amblyomma varium, commonly known in Brazil as the "carrapato-gigante-da-pregui a" (sloth's giant tick) is found from southern Central America to Argentina. The present study adds information on the geographical distribution of A. varium, as well as on their hosts, based on material deposited in the main Brazilian collections and on the available literature. Eighty-two vials, containing 191 adult specimens, deposited in five Acari collections between 1930 and 2001, were examined. These vials included data on the host and collection localities. The biology of A. varium is unknown. However it is known that, during the adult stage, the tick presents a high host specificity and is found almost exclusively on the sloths Bradypus tridactylus, B. variegatus, B.torquatus (Bradypodidae), Choloepus hoffmanni and C. didactylus (Megalonychidae). Based on the material examined, the states of Rond nia, Amazonas, Bahia and Alagoas are newly assigned to geographic distribution of A. varium in Brazil.
Flynn, Peter C; Kaufman, W Reuben
Female ticks of the family Ixodidae increase their mass up to 100-fold during the 7-10 day feeding period. We determined the material properties of the alloscutal cuticle of female Amblyomma hebraeum from the time of moulting through to full engorgement. The material properties of the cuticle were evaluated by a Kelvin-Voigt analysis of compliance determined from the stretch of loops of cuticle under stress. There was a 3-fold increase in cuticle dry mass during the first 3 weeks post-moult, during which the ductility and stiffness of the cuticle increased substantially. Under stress, the cuticle displayed time-dependent stretch, with a plastic (non-recoverable) and viscoelastic (recoverable) component. Plastic deformation was reasonably constant in the range 10-15% over a wide range of induced stress above ∼ 0.6 MPa. The plastic component of tick alloscutal cuticle was about 5-10 times higher than that of unsclerotized insect cuticle. Tick cuticle is far more ductile than unsclerotized insect cuticle. Material properties of the cuticle did not change significantly as a function of cuticular water content over the normal range throughout the feeding cycle (13-37% wet mass). Injected dopamine (DA) reduced one measure of the viscosity of the cuticle by 38%. Plastic deformability of the cuticle was reduced by 70% after an in vitro stretch, but restored in fully engorged ticks, and in in vitro stretched loops by treatment with DA and reduced pH. Thinning of the cuticle by half during the rapid phase of engorgement requires plastic deformation (irreversible strain) in two orthogonal dimensions in excess of 40%. Treatment with DA increased plastic deformation and enabled extensibility (strain at the point of rupture) above 40%. © 2015. Published by The Company of Biologists Ltd.
Paddock, Christopher D; Goddard, Jerome
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.
Swei, A; Meentemeyer, R; Briggs, C J
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.
Banajee, K. H.; Verhoeve, V. I.; Harris, E. K.; Macaluso, K. R.
Rickettsia parkeri Luckman (Rickettsiales: Rickettsiaceae) is a pathogenic spotted fever group Rickettsia transmitted by Amblyomma maculatum Koch (Acari: Ixodidae) in the United States. The acute innate immune response to this pathogen and the effect of tick feeding or salivary components on this response is largely unknown. We hypothesized that A. maculatum saliva enhances R. parkeri infection via downregulation of the acute cellular and cytokine immune response. C3H/HeN mice were intradermally inoculated with R. parkeri both with and without A. maculatum saliva. Flow cytometry and microscopic evaluation of inoculation site skin suspensions revealed that neutrophils and macrophages predominated at 6 and 24 h post R. parkeri inoculation, respectively. This cellular influx was significantly downregulated when A. maculatum saliva was inoculated along with R. parkeri. Inflammatory cytokines (interferon γ and interleukins 6 and 10) were significantly elevated after R. parkeri inoculation. However, cytokine concentration and rickettsial load were not significantly modified by A. maculatum saliva during the acute phase of infection. These results revealed that tick saliva inhibits the cutaneous cellular influx during the acute phase of rickettsial infection. Further study is needed to determine the overall impact of this effect on the establishment of rickettsiosis in the host and development of disease. PMID:27521760
Yu, Zhijun; Thomson, Euan L S; Liu, Jingze; Dennis, Jonathan J; Jacobs, René L; Kaufman, W Reuben
Untreated eggs of the tick Amblyomma hebraeum Koch (Acari: Ixodidae) exhibited antimicrobial activity (AMA) against Gram-negative but not Gram-positive bacteria; eggs denuded of wax by solvent extraction showed no AMA. The unfractionated egg wax extract, however, showed AMA against Gram-positive but not Gram-negative bacteria, as also shown by Arrieta et al. (Exp Appl Acarol 39: 297-313, 2006). In this study we partitioned the egg wax into various fractions, using a variety of techniques, analyzed their compositions, and tested them for AMA. The crude aqueous extract exhibited AMA. However, although more than 30 metabolites were identified in this extract by nuclear magnetic resonance analysis, none of them seemed likely to be responsible for the observed AMA. In the crude organic extract, cholesterol esters were the most abundant lipids, but were devoid of AMA. Fatty acids (FAs), with chain lengths between C13 and C26 were the next most abundant lipids. After lipid fractionation and gas chromatography/mass spectroscopy, free FAs, especially C16:1 and C18:2, accounted for most of the AMA in the organic extract. The material responsible for AMA in the crude aqueous extract remains unidentified. No AMA was detected in the intracellular contents of untreated eggs.
Campos, Roseane Nunes de Santana; Nascimento Lima, Cecília Beatriz; Passos Oliveira, Alexandre; Albano Araújo, Ana Paula; Fitzgerald Blank, Arie; Barreto Alves, Péricles; Nascimento Lima, Rafaely; Albano Araújo, Vinícius; Santana, Alisson Silva; Bacci, Leandro
Ticks are arthropods widely distributed in tropical and subtropical regions, which can transmit infectious agents also responsible for zoonoses. Excessive use of conventional acaricides has resulted in the onset of drug resistance by these parasites, thus the need to use alternative methods for their control. This study evaluated the acaricidal activities of Chrysopogon zizanioides (vetiver) essential oils containing different zizanoic and khuzimol (high and low acidity) acid concentrations on Amblyomma cajennense and Rhipicephalus microplus (Acari: Ixodidae). To this aims, toxicity tests of different concentrations of examined essential oils were conducted on adult females and larval stages. Results showed that the essential oils of C. zizanioides with high and low acidity reduced oviposition of females, eggs hatch and larval survival, being more effective than some commercial products widely used to control these ectoparasites. These results indicate that the C. zizanoides essential oils are promising candidates as acaricidal agents and represent also an add value to vetiver oil with high acidity, which is commercially undervalued in the cosmetic industry.
Guglielmone, Alberto A; Venzal, José M; González-Acuña, Daniel; Nava, Santiago; Hinojosa, Ana; Mangold, Atilio J
The female of Ixodes stilesi Neumann, 1911 (Acari Ixodidae) is redescribed and the male and nymph are described from specimens collected from Pudu puda (Molina) (Artiodactyla: Cervidae) in Chile. Both sexes of I. stilesi have characteristics of the subgenera Ixodes Latreille, 1795 and Ixodiopsis Filippova, 1957. The females of I. stilesi are peculiar in having the combination of the sinuous scutum outline, rounded porose areas with distinct borders separated by the width of one area, slender and long palpi, and two subequal spurs on coxa I. The male is unique in having a combination of a posteriorly wrinkled marginal folder, a basis capituli longer than wide, a non-crenulate hypostome toothed portion, two spurs on coxa II to IV and the presence of a pseudoscutum. The nymph of I. stilesi has blunt anterior and posterior processes on palpal article I (characteristics of the subgenus Ixodiopsis and some Pholeoixodes Schulze, 1942) and a wing-shaped basis capituli with a prominent triangular cornua. Phylogenetic analyses based on 16S mitochondrial rDNA sequences of 12 Neotropical and two Australian Ixodes species, plus three argasids, were carried out to clarify the position of I. stilesi. The results of phylogenetic analyses and morphological characters indicate a close relationships between I. stilesi and two other Neotropical species of uncertain subgeneric status, I. neuquenensis Ringuelet, 1947 and I. sigelos Keirans, Clifford & Corwin, 1976.
Kleinjan, Joyce E.; Lane, Robert S.
In California, hard (Ixodidae) ticks transmit at least 8 zoonotic disease agents (1 virus, 6 bacteria, 1 protozoan) to humans or other animals. The correct taxonomic identification of all 3 parasitic stages (larvae, nymphs, adults) of ticks is integral to understanding host-tick associations and disease dynamics, but immature ticks, especially the larvae, can be difficult to identify. Here, we present larval keys to the 4 genera of Ixodidae (Dermacentor Koch, 1844; Haemaphysalis Koch, 1844; Ixodes Latreille, 1795; Rhipicephalus Koch, 1844) and to the 18 species of Ixodes known to be established in California. Several new diagnostic features, as well as photographs of microscopic structures, are provided to facilitate identification. Non-exclusive characters are utilized to separate the subgenera Ixodiopsis Filippova, 1957 and Pholeoixodes Schulze, 1942. PMID:20027236
Behavioral bioassays remain a standard tool in the discovery, development, and registration of repellents. Tick repellent bioassays tend to be rather uncomplicated, but several factors can influence their outcomes. Using lone star tick, Amblyomma americanum (L.), nymphs in climbing bioassays, we tes...
Elias, Susan P; Lubelczyk, Charles B; Rand, Peter W; Lacombe, Eleanor H; Holman, Mary S; Smith, Robert P
We evaluated the relationships between forest understory structure and the abundance of questing adult and nymphal blacklegged ticks, Ixodes scapularis Say (Acari: Ixodidae), in three Maine towns endemic for Lyme disease, 2001-2003. In fragmented New England woodlands, over-abundant white-tailed deer, Odocoileus virginianus Zimmerman, overbrowse palatable species, allowing browse-resistant exotic-invasive species to replace native forest understory structures. We predicted there would be more ticks in plots dominated by exotic-invasive shrubs (such as Japanese barberry, Berberis thunbergii DC) than in plots dominated by native shrubs, ferns, or open understory. We assessed canopy composition and closure, tree basal area, litter composition, percentage of coverage and stem density of understory species, litter depth, soil moisture, and abundance of small mammals and white-tailed deer pellet groups. We used generalized linear mixed model analysis of covariance to determine the effect of understory structure on tick counts, controlling for continuous habitat and host covariates and adjusting for random spatial effects. There were twice as many adults and nearly twice as many nymphs in plots dominated by exotic-invasives than in plots dominated by native shrubs. Both adult and nymphal counts were lowest in open understory with coniferous litter. Adults were positively associated with increasing litter depth, medium soil moisture, and increasing abundance of white-footed deer mice, Peromyscus leucopus Rafinesque, and deer pellet group counts. Nymphs were positively associated with increasing litter depth, moderately wet soil, and mice. We concluded that deer browse-resistant exotic-invasive understory vegetation presented an elevated risk of human exposure to the vector tick of Lyme disease.
Jordan, Robert A; Schulze, Terry L; Jahn, Margaret B
We monitored the abundance of Ixodes scapularis Say (Acari: Ixodidae) and the Lyme disease incidence rate after the incremental removal of white-tailed deer, Odocoileus virginianus Zimmermann, within a suburban residential area to determine whether there was a measurable decrease in the abundance of ticks due to deer removal and whether the reduction in ticks resulted in a reduction in the incidence rate within the human population. After three seasons, the estimated deer population was reduced by 46.7%, from the 2002 postfawning estimate of 2,899 deer (45.6 deer per km2) to a 2005 estimate of 1,540 deer (24.3 deer per km2). There was no apparent effect of the deer culling program on numbers of questing I. scapularis subadults in the culling areas, and the overall numbers of host-seeking ticks in the culling areas seemed to increase in the second year of the program. The Lyme disease incidence rate generated by both passive and active surveillance systems showed no clear trend among years, and it did not seem to vary with declining deer density. Given the resources required to mount and maintain a community-based program of sufficient magnitude to effectively reduce vector tick density in ecologically open situations where there are few impediments to deer movement, it may be that deer reduction, although serving other community goals, is unlikely to be a primary means of tick control by itself. However, in concert with other tick control interventions, such programs may provide one aspect of a successful community effort to reduce the abundance of vector ticks.
Description of a new species of Ixodes Latreille, 1795 (Acari: Ixodidae) and redescription of I. lasallei Méndez & Ortiz, 1958, parasites of agoutis and pacas (Rodentia: Dasyproctidae, Cuniculidae) in Central and South America.
Apanaskevich, Dmitry A; Bermúdez, Sergio E
Ixodes bocatorensis n. sp. (Acari: Ixodidae), is described based on adults ex agoutis (Rodentia: Dasyproctidae), pacas (Rodentia: Cuniculidae) and "tapir and sloth" (Perissodactyla: Tapiridae and Pilosa) from Colombia, Panama and Venezuela. Adults of I. bocatorensis n. sp. are similar to those of I. lasallei Méndez & Ortiz, 1958 but can be distinguished by the scutum dimensions, punctation pattern, gnathosoma and palpi measurements and their ratios, basis capituli anterior angle and shape of the spur of palpal segment I ventrally. For comparative purposes the female of I. lasallei is redescribed and the true male of this species is described for the first time. Studied adults of I. lasallei were found on agoutis, pacas and ocelot (Carnivora: Felidae) in Colombia, Peru and Venezuela.
First description of the male and redescription of the female of Ixodes tapirus Kohls, 1956 (Acari: Ixodidae), a parasite of tapirs (Perissodactyla: Tapiridae) from the mountains of Colombia, Costa Rica and Panama.
Apanaskevich, Dmitry A; Domínguez, Lillian G; Torres, Sugeys S; Bernal, Juan A; Montenegro, Victor M; Bermúdez, Sergio E
The male of Ixodes tapirus Kohls, 1956 (Acari: Ixodidae) is described for the first time and the female is redescribed in greater detail. Adults of I. tapirus are similar to those of Ixodes guatemalensis Kohls, 1956, Ixodes lasallei Méndez & Ortiz, 1958, Ixodes montoyanus Cooley, 1944 and Ixodes venezuelensis Kohls, 1953 but can be distinguished by their overall size, the amount of sclerotisation of the conscutum and accessory plates, the shape of the scutum, the number of punctations and their pattern on the conscutum and scutum, the depth of the punctations on the basis capituli dorsally, the shape and size of the porose areas and the size and shape of the auriculae. Adults of I. tapirus were collected from tapirs and vegetation in the mountains of Colombia, Panama and recorded from Costa Rica for the first time.
Black, W C; Piesman, J
Ticks are parasitiform mites that are obligate hematophagous ectoparasites of amphibians, reptiles, birds, and mammals. A phylogeny for tick families, subfamilies, and genera has been described based on morphological characters, life histories, and host associations. To test the existing phylogeny, we sequenced approximately 460 bp from the 3' end of the mitochondrial 16S rRNA gene (rDNA) in 36 hard- and soft-tick species; a mesostigmatid mite, Dermanyssus gallinae, was used as an outgroup. Phylogenies derived using distance, maximum-parsimony, or maximum-likelihood methods were congruent. The existing phylogeny was largely supported with four exceptions. In hard ticks (Ixodidae), members of Haemaphysalinae were monophyletic with the primitive Amblyomminae and members of Hyalomminae grouped within the Rhipicephalinae. In soft ticks (Argasidae), the derived phylogeny failed to support a monophyletic relationship among members of Ornithodorinae and supported placement of Argasinae as basal to the Ixodidae, suggesting that hard ticks may have originated from an Argas-like ancestor. Because most Argas species are obligate bird octoparasites, this result supports earlier suggestions that hard ticks did not evolve until the late Cretaceous. PMID:7937832
Ponnusamy, Loganathan; Gonzalez, Antonio; Van Treuren, Will; Weiss, Sophie; Parobek, Christian M; Juliano, Jonathan J; Knight, Rob; Roe, R Michael; Apperson, Charles S; Meshnick, Steven R
Ticks are important vectors for many emerging pathogens. However, they are also infected with many symbionts and commensals, often competing for the same niches. In this paper, we characterize the microbiome of Amblyomma americanum (Acari: Ixodidae), the lone star tick, in order to better understand the evolutionary relationships between pathogens and nonpathogens. Multitag pyrosequencing of prokaryotic 16S rRNA genes (16S rRNA) was performed on 20 lone star ticks (including males, females, and nymphs). Pyrosequencing of the rickettsial sca0 gene (also known as ompA or rompA) was performed on six ticks. Female ticks had less diverse microbiomes than males and nymphs, with greater population densities of Rickettsiales. The most common members of Rickettsiales were "Candidatus Rickettsia amblyommii" and "Candidatus Midichloria mitochondrii." "Ca. Rickettsia amblyommii" was 2.6-fold more common in females than males, and there was no sequence diversity in the sca0 gene. These results are consistent with a predominantly vertical transmission pattern for "Ca. Rickettsia amblyommii."
Durden, Lance A; Beckmen, Kimberlee B; Gerlach, Robert F
During 2010-2016, tick specimens were solicited from veterinarians, biologists, and members of the public in Alaska. Eight species of ticks were recorded from domestic dogs. Some ticks were collected from dogs with recent travel histories to other countries or other U.S. states, which appears to explain records of ticks not native to Alaska such as Amblyomma americanum (L.) (lone star tick), Ixodes scapularis (Say) (blacklegged tick), and Ixodes ricinus (L.). However, we recorded Dermacentor variabilis (Say) (American dog tick) from dogs (and humans) both with and without travel history, suggesting that this nonindigenous tick could be establishing populations in Alaska. Other ticks commonly recorded from dogs included the indigenous Ixodes angustus Neumann and the invasive Rhipicephalus sanguineus (Latreille) (brown dog tick). Domestic cats were only parasitized by one tick species, the native I. angustus Six species of ticks were recorded from humans: A. americanum (with and without travel history), Dermacentor andersoni Stiles (Rocky Mountain wood tick; travel associated), D. variabilis (with and without travel history), Haemaphysalis leporispalustris (Packard) (rabbit tick, native to Alaska), I. angustus, and R. sanguineus. Ixodes angustus predominated among tick collections from native mammals. Also, Ixodes texanus Banks (first record from Alaska) was collected from an American marten, Martes americana (Turton), H. leporispalustris was recorded from a snowshoe hare, Lepus americanus Erxleben, and Ixodes auritulus Neumann was collected from a Northwestern crow, Corvus caurinus Baird. The establishment of D. variabilis, D. andersoni, A. americanum, and/or I. scapularis in Alaska would have strong implications for animal and human health. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Loftis, Amanda D; Kelly, Patrick J; Paddock, Christopher D; Blount, Keith; Johnson, Jason W; Gleim, Elizabeth R; Yabsley, Michael J; Levin, Michael L; Beati, Lorenza
Panola Mountain Ehrlichia (PME) has been suggested as an emerging pathogen of humans and dogs. Domestic goats and white-tailed deer (Odocoileus virginianus) are also susceptible and likely serve as reservoirs. Experimentally, both the lone star tick (Amblyomma americanum (L.)) and the Gulf Coast tick (Amblyomma maculatum Koch) can transmit PME among deer and goats. In the current study, we detected PME in adult wild-caught A. maculatum from the United States and Amblyomma variegatum (F.) from the Caribbean and Africa. This significantly expands the range, potential tick vectors, and risk for exposure to PME.
Carroll, J F
Host-seeking ticks often remain on clothing of persons returning home from work or recreation in tick habitats, and can pose at least a temporary risk to people and pets in these homes. Laundering clothing has been one of the recommendations to reduce tick exposure. Host-seeking lone star tick, Amblyomma americanum (L.), and blacklegged tick, Ixodes scapularis Say, nymphs confined in polyester mesh packets, were included with laundry in cold, warm, and hot wash cycles of an automatic clothes washer. Ticks were also placed with washed clothing and subjected to drying in an automatic clothes dryer set on high heat and on air only (unheated). Most nymphs (> or = 90%) of both species survived the cold and warm washes, and 95% of A. americanum nymphs survived the hot wash. At the time of their removal from the washer, I. scapularis nymphs were clearly affected by the hot wash, but 65% were considered alive 20-24 h later. Large percentages of nymphs of both species survived hot washes in which two other detergents (a powder containing a nonchlorine bleach and a liquid) were used. All ticks were killed by the 1 h cycle at high heat in the clothes dryer, but with unheated air some nymphs of both species survived the 1 h cycle in the dryer. Given the laundering recommendations of clothing manufacturers and variation in the use automatic clothes washers, laundry washed in automatic washers should not be considered free of living ticks.
Estrada-Peña, Agustín; de la Fuente, José; Cabezas-Cruz, Alejandro
The distribution of Amblyomma americanum (L.) in the continental United States has been modelled using the reported distribution in counties as "established" (six or more ticks or two or more life stages were recorded during a specified time period), "reported" (fewer than six ticks of a single life stage were recorded), or "absent" (neither of the above categories were met) and a set of environmental and biotic explanatory variables. Categorical (vegetation, climate, and habitat suitability for the main host of the tick) or continuous variables (raw data on temperature, vegetation, and habitat fragmentation), as well as the processes of the tick's life cycle, were tested to build models using multiple logistic regression. The best results were obtained when the life cycle processes were used as descriptors of regressions. Better models derived from life cycle processes were obtained after inclusion of habitat suitability for the white tailed deer (the main host of the tick) and landscape fragmentation. Using this approach, 86% of "absent" and 83% of "established" counties were classified correctly, but all "reported" counties were erroneously classified. Modelling life cycle processes with descriptions of host abundance and habitat fragmentation produced the best outcome when coordinates were missing. When only standard categorical descriptors of climate or vegetation were included in models, results produced poor outcomes. Models were improved with remotely sensed information on temperature and vegetation but produced high rates of misclassification for 14% of "absent", 37% of "established", and 100% of "reported" counties. Modelling produced poor results in the absence of point distributions (coordinates). Therefore, "reported" counties cannot be handled adequately by modelling procedures, probably because this category does not reflect the true status of the tick distribution. We conclude that standard categorical classifications of the distribution of an
Stein, Kenneth J; Waterman, Megan; Waldon, Jefferson L
Larval, nymphal, and adult Amblyomma americanum (L.), and adult Dermacentor variabilis (Say) ticks were collected using timed dragging techniques, in an attempt to examine how different habitat variables affect models that describe the distribution of ticks in Virginia, USA. Tick count data were modeled using two approaches: (i) habitat and edge, and (ii) habitat, edge, vegetation density and levels of disturbance. Nymphs and adults tended to follow a forest edge distribution when analysed by habitat and edge. Using all variables, we detected a positive relationship with forest edges and negative associations with high-density vegetation. When larvae were modeled by habitat and edge, we failed to detect associations with the edges of habitats. When all variables were included in the larval analysis, disturbed meadow edges emerged as important in the first year, and the categories of disturbed and maturing habitat in the second year. Vegetation density and levels of disturbance were marginally important towards explaining the distribution of nymphs and adults; however, levels of disturbance were potentially more important to the distribution of larvae, than habitat types. Using the habitat and edge variables, and predicted mean encounter rates for all stages of A. americanum and adult D. variabilis, we successfully cross-validated our predictions of high, moderate and low tick densities in both years. The results for nymphs and adults were combined to develop a colour-coded threat assessment map. We estimated that the majority of ticks were located on approximately 20% of the landscape. The potential uses of geographical information system-based threat maps are discussed.
Lah, Ernieenor Faraliana Che; Yaakop, Salmah; Ahamad, Mariana; George, Ernna; Nor, Shukor Md
Identification of a local species of tick, Ixodes granulatus from the family Ixodidae is essential because it has potential to be vector for spotted fever group (SFG) rickettsia and tick thypus. The aim of this study is to portray the relationships among several populations of I. granulatus collected from different species of animal hosts and localities in Peninsular Malaysia. Polymerase Chain Reaction was conducted by amplifying mitochondrial DNA marker, namely cytochrome oxidase subunit I (COI) sequences from 15 individual ticks that attached to five different hosts caught from three different localities. Confirmation of the species identity was accomplished using BLAST program. Neighbor-joining (NJ) and Maximum Parsimony (MP) tree based on COI sequences were constructed by using PAUP 4.0b10 to identify the relationship among species. The result of this study showed a high genetic heterogeneity between I. granulatus and other species of the same genus (7.2-23.7%). Furthermore, a low intraspecific variation was observed among the species of I. granulatus collected from different localities (0-3.7%). This study produced the first establishment of molecular marker for clarifying genetic species variation and diversity of local I. granulatus tick which contribute to the control of tick-borne infections.
seedlings and saplings of the dominant canopy species, greenbrier (Smilax rotunifolia L. ), highbush blueberry (Vaccinium corymbosum L.), and huckle...patches of highbush blueberry , huckle berries, and grasses. The Perrineville Lake Park site is a mid-successional forest with a mixed canopy includ
The present study was conducted to elucidate the neuronal pathways between peripheral olfactory and taste sensilla and the synganglion in an Ixodidae tick species. The tarsus of the front legs (olfactory nerves) and the fourth palpal segment (gustatory nerves) of unfed Amblyomma americanum males and...
Guglielmone, Alberto A; Nava, Santiago
A major, but not exhaustive, literature revision has been made to compile the names of Ixodidae from Linnaeus to present. Names are classified as valid, synonyms, lapsus, incertae sedis, nomina dubia, nomina nuda, incorrect and suppressed. Notes are included for confusions and misidentifications among different tick species. The lists included in this study are neither aimed to be consensual nor focusing to stabilize nomenclature, but rather part of a discussion on the species forming Ixodidae and a potential aid for research on tick taxonomy and phylogeny.
Brannan, Jaime L; Riggs, Penny K; Olafson, Pia U; Ivanov, Ivan; Holman, Patricia J
The Lone Star tick, Amblyomma americanum Linnaeus 1758 (Acari; Ixodidae), causes considerable production losses to the southern U.S. cattle industry due to reduced weight, infertility, secondary infections at bite wound sites, damaged hides, and potentially death, as these ticks tend to infest livestock in large numbers. Increasing environmental concerns, along with the potential for chemical residue in food products, have led to more emphasis on alternative tick control strategies, such as selective breeding practices and anti-tick vaccines. To enable progress toward these goals, a better understanding of bovine host immune mechanisms elicited by ticks is needed. In this study, 7 calves were phenotyped as susceptible, moderately resistant, or highly resistant to adult A. americanum ticks. Tick bite-site biopsies and blood leukocytes were collected at multiple time points throughout 3 successive tick infestations. Gene expression at tick bite-site biopsies was assessed by microarray analysis over 3 time points for each phenotype group. Quantitative reverse transcriptase-PCR expression analysis evaluated 11 candidate genes in tick bite-site biopsies, and 6 in blood leukocytes. Regression curve estimates calculated from the expression values generated by qRT-PCR in tick bite-sites identified correlations between several candidate genes. Increased expression of IGHG1, IL6, IL1α, and IL1RN in bovine tick bite-site biopsies suggests that Th2 differentiation may be important for the local bovine response to A. americanum ticks. Strong correlations in expression for IL1α and IL1β, for IL1α and IL1RN, and for IL1α and TLR4 were found in biopsies from the tick-resistant phenotypes. The up-regulation of IL12 and IL23 in blood leukocytes from Lone Star tick-infested calves of all phenotypes suggests a possible systemic recruitment of memory T cells. This study provides novel insight concerning the bovine immune response to Lone Star ticks and a basis for future
Bacon, Rendi Murphree; Pilgard, Mark A; Johnson, Barbara J B; Raffel, Sandra J; Schwan, Tom G
A glpQ ortholog was identified in DNA from Borrelia lonestari-positive Amblyomma americanum, providing further evidence that B. lonestari is more closely related to the relapsing fever group spirochetes than to borreliae that cause Lyme disease. This finding provides a basis for developing diagnostic assays to differentiate species of borrelia transmitted by hard ticks.
Over a seven year period, we monitored the effect of a commercially available, amitraz impregnated anti-tick collar in controlling free-living populations of lone star ticks, Amblyomma americanum (L.) when manually fitted around necks of white-tailed deer, Odocoileus virginianus (Zimmermann). Study...
Infection and co-infection rates of Anaplasma phagocytophilum variants, Babesia spp., Borrelia burgdorferi, and the rickettsial endosymbiont in Ixodes scapularis (Acari: Ixodidae) from sites in Indiana, Maine, Pennsylvania, and Wisconsin.
Steiner, Fresia E; Pinger, Robert R; Vann, Carolyn N; Grindle, Nate; Civitello, David; Clay, Keith; Fuqua, Clay
In total, 394 questing adult blacklegged ticks, Ixodes scapularis Say (Acari: Ixodidae), collected at four sites were analyzed by polymerase chain reaction (PCR) for five microbial species: Anaplasma phagocytophilum, Babesia microti, Babesia odocoilei, Borrelia burgdorferi, and the rickettsial I. scapularis endosymbiont. Identities of genetic variants of A. phagocytophilum were determined by sequencing a portion of the 16S DNA. In 55% of infected ticks (193/351), a single agent was detected. In 45% (158/351), two or more agents were detected; 37% harbored two agents and 8% harbored three agents. One male tick, collected from Ft. McCoy, WI, harbored all four microbial genera The highest rates of co-infection were by the Ixodes endosymbiont and B. burgdorferi (95/351). Two species of Babesia co-occurred within a single tick population in Wells National Estuarine Research Reserve, Wells, ME, whereas only B. odocoilei was found in other tick populations. Only A. phagocytophilum human anaplasmosis variant was detected in questing ticks from Tippecanoe River State Park, IN; from Wells; and Ft. McCoy, whereas a single infected tick from Presque Isle, PA, was infected by AP-Variant 1. Partially engorged ticks from deer in Tippecanoe River State Park were all infected with AP-Variant 1. Frequency of infections with each agent varied among populations. Rates and types of co-infections were not significantly different from random except for the Ixodes endosymbiont and B. burgdorferi in male ticks, which co-occurred less frequently than expected. Thus, I. scapularis hosts an array of pathogenic and symbiotic agents and potential evidence of interactions among microbial species was observed.
Barbosa, Carolina da Silva; Borges, Lígia Miranda Ferreira; Louly, Carla Cristina Braz; Rocha, Thiago Lopes; de Sabóia-Morais, Simone Maria Teixeira; Miguita, Carlos Henrique; Garcez, Walmir Silva; Garcez, Fernanda Rodriguez
We evaluated the effects of 3β-O-tigloylmelianol from Guarea kunthiana A. Juss (Meliaceae) on oogenesis, as a larvicide and on ecdysis of the larvae and the nymphs of the cattle tick Rhipicephalus (Boophilus) microplus (Canestrini) (Acari: Ixodidae). On the oogenesis' test, 48 engorged females were divided into three groups, evaluated at 24, 48 and 72 h post-treatment. Half of the females were treated with 0.01% 3β-O-tigloylmelianol diluted in distilled water and 5% dimethyl sulfoxide (DMSO), while the other half (controls) were exposed to distilled water and 5% DMSO. After treatment, the ovaries were weighed in order to measure the gonadosomatic index (GSI) and were also subjected to standard histological technical tests. On the larvicide and ecdysis' tests, 3β-O-tigloylmelianol was tested at concentrations of 0.01, 0.005, 0.0025 and 0.00125%. Compared with the controls, there was a reduction of GSI of approximately 50% on the treated group, which started at 48 h post treatment. Overall, the protolimonoid 3β-O-tigloylmelianol has caused a significant reduction in the number of oocytes. It has also caused alteration of the cytoplasmic and germinal vesicle diameters. Morphological changes, such as vacuolization, chorion irregularity which has modified the oocytes' morphology as well as alterations on the yolk's granules were also observed. The compound was not larvicide, however, interfered in the ecdysis of the larvae and the nymphs. This study shows that the protolimonoid 3β-O-tigloylmelianol from G. kunthiana acts on oogenesis and ecdysis of R. (B.) microplus, but not as larvicide, indicating that it acts on the endocrine system of the tick.
Chemical composition and acaricidal activity of the essential oil of Baccharis dracunculifolia De Candole (1836) and its constituents nerolidol and limonene on larvae and engorged females of Rhipicephalus microplus (Acari: Ixodidae).
de Assis Lage, Tiago Coelho; Montanari, Ricardo Marques; Fernandes, Sergio Antonio; de Oliveira Monteiro, Caio Márcio; de Oliveira Souza Senra, Tatiane; Zeringota, Viviane; da Silva Matos, Renata; Daemon, Erik
Baccharis dracunculifolia DC (common name "alecrim-do-campo" in Brazil) is a plant with widespread distribution in South America that is the botanical origin of green propolis. The aim of this study was to evaluate the chemical composition and acaricidal activity of the essential oil of B. dracunculifolia and its constituents nerolidol and limonene on unengorged larvae and engorged females of Rhipicephalus microplus (Acari: Ixodidae). The essential oil yield was 0.8% of dry mass and the major constituents were nerolidol (22.3%), germacrene D (7.2%), limonene (6.9%), β-pinene (6.7) and bicyclogermacrene (6.5%). The acaricidal activity of the essential oil and the pure compounds nerolidol and (R)-(+)-limonene were assessed in the laboratory through the modified larval packet test (LPT) and the female immersion test (FIT). In the LPT, the essential oil and nerolidol were both active, causing more than 90% mortality at concentrations from 15.0 and 10.0 mg mL(-1), respectively, whereas (R)-(+)-limonene was not active. In the FIT, the oil and nerolidol caused reduction in the quantity and quality of eggs produced, with control percentages of 96.3% and 90.3% at concentrations of 60.0 and 50.0 mg mL(-1), respectively. It can be concluded that the essential oil obtained from the aerial parts of B. dracunculifolia and its major component nerolidol have high activity on R. microplus larvae and engorged females. Copyright © 2014 Elsevier Inc. All rights reserved.
Dynamics of cell and tissue genesis in the male reproductive system of ticks (Acari: Ixodidae) Amblyomma cajennense [corrected] (Fabricius, 1787) and Amblyomma aureolatum (Pallas, 1772): a comparative analysis.
Sampieri, Bruno Rodrigues; Labruna, Marcelo Bahia; Bueno, Odair Correa; Camargo-Mathias, Maria Izabel
Ticks are classified into three families: Argasidae, Ixodidae, and Nutalliellidae. The taxonomy and phylogeny within Ixodidae are still discussed by the specialists, thus requiring further studies. Amblyomma cajennese and Amblyomma aureolatum (Brazil) belong to two species complexes known as "cajennese" and "ovale", respectively, and are directly related to the transmission of the Brazilian spotted fever. This confirms the medical and veterinary significance of these species, as well as the need for further morphological studies that will bring a better understanding of their taxonomy, phylogeny, and control. In this context, the present study aimed to characterize the morphology of the male reproductive system of A. cajennese and A. aureolatum when unfed and after 4 days of feeding, thereby seeking to: (a) distinguish the two species or "complexes", and (b) study an internal system which has the potential to be targeted by acaricides. Therefore, males from both species (unfed and after 4 days of feeding) were cold-anesthetized, dissected, and had their reproductive systems removed for histological analysis. The results showed that the morphology of the male reproductive system is generally similar between both species, like in other Ixodidae ticks, exhibiting a multilobed accessory gland complex related to seminal fluid secretion, a pair of vasa deferentia and a pair of testes housing germ cells (spermatocytes) in different stages. The main differences were found in the development of the accessory gland complex cells and germ cells, showing that the maturation of the male reproductive system starts later in A. aureolatum, when compared to A. cajennese. However, during the blood meal, A. aureolatum development is increased, thus making germ cell maturation and gland complex activity higher than in A. cajennese. This study shows the differences in the development of the male reproductive systems of both species, while providing information that can assist in the
Martins, João R; Monticelli, Elida C; Onofrio, Valéria C; Barros-Battesti, Darcy M; Doyle, Rovaina L
Amblyomma fuscum known only from Brazil has been described as a rare tick species with few reports of its occurrence in South and Southeast region. This is a new records this tick species (9 females) parasitizing lizard (Tupinambis teguixin) at the Municipality of Glorinha, State of Rio Grande do Sul. The females were deposited in the tick collection of Veterinary Research Institute Desiderio Finamor (7 specimens), Eldorado do Sul, RS and in the Acari collection from Instituto Butantan, São Paulo, State of São Paulo (2 specimens). The finding confirms establishment de A. fuscum in the South of Brazil.
Rivera-Páez, Fredy Arvey; Sampieri, Bruno Rodrigues; Labruna, Marcelo Bahia; da Silva Matos, Renata; Martins, Thiago Fernandes; Camargo-Mathias, Maria Izabel
Among tick species, members of the subfamily Amblyomminae have received special attention, since they serve as vectors for pathogens such as Rickettsia spp. and display cryptic species complexes that make their taxonomical classification challenging. Amblyomma ovale, Amblyomma maculatum, and other species of the genus Amblyomma have shown a long history of taxonomic controversies. Spermiotaxonomy has proved to be a valuable tool in the solution of systematic conflicts in Metazoa that can aid molecular and external morphological analyses in ticks and, overall, provide more robust analyses and results. With this in mind, this study included histological analyses of the reproductive system of the species A. ovale and A. maculatum, as well as the description of morphohistological characters of the male reproductive system of ticks of the genus Amblyomma, in order to evaluate these characters within the current clustering proposals. In addition, 16S rDNA and COI (mitochondrial) molecular markers were used to study the genetic relationships of the species. The results show that the tick male reproductive system and its germ cells contain useful candidate characters for taxonomical analyses of Ixodida.
Williams-Newkirk, Amanda J; Burroughs, Mark; Changayil, Shankar S; Dasch, Gregory A
Amblyomma americanum is an abundant tick in the southeastern, midwestern, and northeastern United States. It is a vector of multiple diseases, but limited genomic resources are available for it. We sequenced the complete mitochondrial genome of a single female A. americanum collected in Georgia using the Illumina platform. The consensus sequence was 14,709 bp long, and the mean coverage across the assembly was >12,000×. All expected tick genomic features were present, including two "Tick-Box" motifs, and in the expected order for the Metastriata. Heteroplasmy rates were low compared to the most closely related tick for which data are available, Amblyomma cajennense. The phylogeny derived from the concatenated protein coding and rRNA genes from the 33 available tick mitochondrial genomes was consistent with those previously proposed for the Acari. This is the first complete mitochondrial sequence for A. americanum, which provides a useful reference for future studies of A. americanum population genetics and tick phylogeny. Copyright © 2015 Elsevier GmbH. All rights reserved.
Pound, J M; Lohmeyer, K H; Davey, R B; Miller, J A; George, J E
Over a 7 yr period, we monitored the effect of a commercially available, amitraz impregnated anti-tick collar in controlling free-living populations of lone star ticks, Amblyomma americanum (L.) when manually fitted around necks of white-tailed deer, Odocoileus virginianus (Zimmermann). Study animals in treatment and control groups were confined in 38.8 ha game-fenced and densely vegetated treatment plots in South Texas. Tick densities during years 1 and 7 served as untreated pre- and posttreatment comparisons and treatments occurred during years 2 through 5. Reductions in tick densities in the treatment plot were compared against tick densities in a control plot having similar vegetation and numbers of untreated deer. During years of treatment, indices of control pressure ranged from 18.2 to 82.6 for nymphs and 16.9-78.7 for adults, and efficacy, expressed as percentage control during the final year of treatment, was 77.2 and 85.0%, respectively, for nymphal and adult ticks. These data show that acaricidal collar treatments provide efficacies very similar to those achieved with the existing ivermectin-medicated bait and '4-Poster' topical treatment technologies to control ticks feeding on wild white-tailed deer.
Bloemer, S R; Mount, G A; Morris, T A; Zimmerman, R H; Barnard, D R; Snoddy, E L
A project on management of lone star ticks, Amblyomma americanum (L.), at Land Between the Lakes, a Tennessee Valley Authority recreational area in Kentucky-Tennessee, during 1984-1988, demonstrated the effectiveness and economics of three control technologies. Acaricide applications (chlorpyrifos at 0.28 kg [AI]/ha), vegetative management (mowing and removal of 40% overstory and 90-100% of midstory, understory, and leaf litter), and host management (white-tailed deer exclusion from a 71-ha campground with a single-line fence) provided 75, 70, and 64% mean controls of all life stages of the lone star tick, respectively. Combinations of acaricide applications + vegetative management, acaricide applications + host management, and acaricide applications + vegetative management + host management produced 94, 89, and 96% mean control of all life stages, respectively. The costs of acaricide applications (two per year), vegetative management (two mowings per year), and white-tailed deer exclusion (single-line fence) were $45, $150, and $30/ha/yr, respectively. Results of this project are used to design management strategies that could be considered for use against lone star ticks in recreational areas.
Kurtti, Timothy J; Simser, Jason A; Baldridge, Gerald D; Palmer, Ann T; Munderloh, Ulrike G
Rickettsia peacockii, a spotted fever group rickettsia, is a transovarially transmitted endosymbiont of Rocky Mountain wood ticks, Dermacentor andersoni. This rickettsia, formerly known as the East Side Agent and restricted to female ticks, was detected in a chronically infected embryonic cell line, DAE100, from D. andersoni. We examined infectivity, ability to induce cytopathic effect (CPE) and host cell specificity of R. peacockii using cultured arthropod and mammalian cells. Aposymbiotic DAE100 cells were obtained using oxytetracycline or incubation at 37 degrees C. Uninfected DAE100 sublines grew faster than the parent line, indicating R. peacockii regulation of host cell growth. Nevertheless, DAE100 cellular defenses exerted partial control over R. peacockii growth. Rickettsiae existed free in the cytosol of DAE100 cells or within autophagolysosomes. Exocytosed rickettsiae accumulated in the medium and were occasionally contained within host membranes. R. peacockii multiplied in other cell lines from the hard ticks D. andersoni, Dermacentor albipictus, Ixodes scapularis, and Ixodes ricinus; the soft tick Carios capensis; and the lepidopteran Trichoplusia ni. Lines from the tick Amblyomma americanum, the mosquito Aedes albopictus, and two mammalian cell lines were non-permissive to R. peacockii. High cell densities facilitated rickettsial spread within permissive cell cultures, and an inoculum of one infected to nine uninfected cells resulted in the greatest yield of infected tick cells. Cell-free R. peacockii also were infectious for tick cells and centrifugation onto cell layers enhanced infectivity approximately 100-fold. The ability of R. peacockii to cause mild CPE suggests that its pathogenicity is not completely muted. An analysis of R. peacockii-cell interactions in comparison to pathogenic rickettsiae will provide insights into host cell colonization mechanisms.
tapir , locality unknown, 1917, coll. E. Joukowsky). The other Paraguayan specimens of Am. triste in the USNTC, all collected in Estancia Faro Moro by...Experimental Station and Filadelfia, and has been found on cattle and horses in Villarica and on tapir in Colonia Risso (Berlese, 1888; Tonelli Rondelli, 1931
Abstract The present paper is based on original and literature data. In Croatia the first studies on the occurrence of ixodid species were made about 80 years ago. The number of tick species recorded in Croatia considerably increased during the 1950s, 60s, 70s and 80s of the past century. A total of 21 species of hard tick belonging to 5 genera have been recorded in Croatia. Ixodes is the best represented genus, with seven species recorded. Haemaphysalis is represented by six species, followed by Rhipicephalus with four species. Dermacentor and Hyalomma are represented by two species each. The ticks were collected on 47 different host species. Eleven tick species were collected on Bos taurus and Ovis aries, followed by Capra hircus and Equus caballus with 8 species and Canis lupus familiaris with 6 species. On the remaining 42 host species one, two or three tick species were collected. The most widespread tick is Ixodes ricinus which was found on 25 different host species. PMID:23372407
Nava, Santiago; Estrada-Peña, Agustín; Mangold, Atilio J; Guglielmone, Alberto A
The life cycle of Amblyomma neumanni was described studying the seasonal distribution of free-living stages and parasitic phases during two consecutive years. Development periods of engorged ticks under different photoperiod conditions were recorded. Larvae of A. neumanni have the peak of abundance in autumn. Nymphs reach the peak in winter. Females were collected on cattle from autumn to late spring. The seasonal distribution pattern of females showed a bimodal curve, with a peak in autumn and other during early and middle spring. The engorged females exposed at shortest photoperiod regimen (10 h light-14 h dark) under both laboratory and field conditions undergo morphogenetic diapause, expressed as a delay in the oviposition. It is concluded that females of A. neumanni that feed and copulate in autumn undergo morphogenetic diapause, and they will lay eggs in spring, simultaneously with the females that feed and copulate in this season. Climate niche analysis shows that adequate suitability for A. neumanni depends mainly from temperature (mean, absolute maximum and minimum, and mean temperature in wettest and driest quarters) as well as from rainfall in warmest and coldest quarters. Sequences of 16S rDNA gene belonging to different populations of A. neumanni, showed no intraspecific genetic differentiation.
de Monteiro, Caio Márcio; Maturano, Ralph; Daemon, Erik; Catunda-Junior, Francisco Eduardo Aragão; Calmon, Fernanda; Senra, Tatiane de Souza; Faza, Aline; de Carvalho, Mário Geraldo
The aim of this study was to evaluate the acaricidal activity of eugenol, with different solubilizations and concentrations, on Rhipicephalus microplus and Dermacentor nitens larvae and to determine the lethal time. The study consisted of four experiments, and the mortality was assessed using the larval packet test with adaptations. The mortality observed in the first experiment was 100 % for all the groups treated with eugenol solubilized in different solvents. In the second, the hydroethanolic formulation of eugenol was used, and the mortality rates for R. microplus and D. nitens was 100 % starting from the concentration of 5.0 μl/ml. In the third experiment, the mortality was 100 % for larvae of both R. microplus and D. nitens after 1 h of contact. And in the fourth experiment, the mortality was above 90 % and statistically similar (p > 0.05) for the four methods the test evaluated.
Sampieri, Bruno Rodrigues; Calligaris, Izabela Bragião; Matos, Renata da Silva; Páez, Fredy Arvey Rivera; Bueno, Odair Corrêa; Camargo-Mathias, Maria Izabel
The phylogenetic relationships among tick species (Acari: Ixodida) have been revisited by several researchers over the last decades. Two subfamilies, Rhipicephalinae (Ixodidae) and Ornithodorinae (Argasidae), deserve special attention. The male reproductive system morphology, as well as the ultrastructure of the germ cells, may provide important information for phylogeny and systematics of metazoan groups, with spermatozoa exhibiting characters that can be used for this purpose. With that information in mind, this study aimed at evaluating, through a comparative analysis, the morphology of the male reproductive systems and germ cells of ticks species Rhipicephalus sanguineus and Ornithodoros rostratus. In order to do that, histology and scanning electron microscopy techniques were used. The results have shown that despite the similarities in the general morphology of the male reproductive system among studied Ixodida so far, there are morphological differences among the species studied herein, mainly the U-shaped testis (ancestral character) in O. rostratus and the pair testes (derived character) in R. sanguineus, and the general morphology of germ cells (spermatids V). Besides that, the morphological changes observed during the spermiogenesis appear to be different between the species studied here, probably characterizing the two families considered. The data generated in this study showed the importance of comparative internal morphology studies, mainly in regard to spermatology, despite the morphological data obtained herein not being enough to product a cladogram (sperm cladistics), it was already possible to observe clear differences among families Argasidae and Ixodidae in regard to the organization of their male reproductive systems and concerning the external morphology of spermatids. Data yet to be obtained through transmission electron microscopy techniques will allow the application of spermiocladistics and spermiotaxonomy as tools for tick systematics.
Bandaranayaka, K O; Apanaskevich, D A; Rajakaruna, R S
Nosomma monstrosum (Nuttall & Warburton) is a hard tick infesting mainly buffalo and cattle in Sri Lanka. Biological data on the life cycle pattern of N. monstrosum were collected using experimental infestation on New Zealand white rabbits under laboratory conditions. The three-host life cycle was completed within 64-102 days. Eggs hatched after 20-29 days of incubation and the larvae hatched out started feeding which lasted for 2-4 days. After a moulting period of 8-11 days nymphs emerge and they actively fed for 2-4 days. Subsequently the nymphs took 15-18 days for moulting before emerging as adults. Freshly moulted females fed for 7-8 days and remained latent for 4-5 days before starting the oviposition. Females laid 3864-12,520 eggs for 11-17 days. The male: female sex ratio was 8:3 in the adults which were moulted under laboratory conditions. Strong positive correlations were found in female weight with number of eggs laid and REI. Females raised from the first generation of eggs had higher oviposition periods, higher REI, laid ten times more eggs, and lower pre-oviposition periods compared to those collected from the wild. When a suitable host is given, N. monstrosum could successfully complete its three-host life cycle under laboratory conditions.
Bandaranayaka, K O; Apanaskevich, D A; Rajakaruna, R S
Amblyomma integrum is a hard tick infesting mainly buffalo and cattle and has been identified as an agent of human otoacariasis in Sri Lanka. Data on the life cycle pattern of A. integrum were collected by experimental infestation on New Zealand white rabbits under laboratory conditions. Wild-caught females laid 55-7389 eggs for 2-35 days after spending a latent period of 10-25 days. Egg incubation period was 31-105 days and the newly emerged larvae started feeding after 4-11 days. Larvae dropped off after feeding and they moulted into nymphs after 10-16 days. Nymphs actively fed on rabbits for 4-8 days and dropped off. Engorged nymphs took 11-25 days for moulting before emerging as adults. The male:female sex ratio of the adults moulted under laboratory conditions was 11:9. All the stages showed periodicity in engorgement and dropping off. The three-host life cycle was completed within 74-245 days with an average of 152.9 days. The mean Reproductive Efficiency Index (REI) and Reproductive Aptitude Index (RAI) were 3.6 and 1.1, respectively. Females hatched in the laboratory did not successfully feed on New Zealand white rabbits. The wild-caught females which fed on buffaloes had prolonged pre-oviposition and oviposition periods, low REI, low RAI and low eclosion under controlled laboratory conditions compared to other tick species. Although larva and nymphs of A. integrum successfully fed on New Zealand white rabbits under laboratory conditions, full life cycle was not completed because the adult females did not feed on rabbits.
Kwak, Mackenzie L; Mintram, Kate
A rare opportunity to travel to Herald's Beacon Islet with permission from the Australian government to collect ticks allowed for a survey of the tick fauna of the island to be undertaken for the first time. The avian fauna of the island, which serve as hosts, was also recorded and includes one new species record for the island. The seabird soft tick Ornithodoros capensis Neumann and the seabird hard tick Amblyomma loculosum Neumann were found to be present on the island. Images of the ticks present on the island are presented along with morphological characters for their identification.
Burazerović, J; Ćakić, S; Mihaljica, D; Sukara, R; Ćirović, D; Tomanović, S
Ticks parasitizing bats have been largely understudied, especially in the central part of the Balkan Peninsula, where the last data from the field research date from almost 25 years ago. Bats are hosts to a large number of ectoparasites, including ticks, which can act as vectors of zoonotic agents. For this reason, it is important to identify the distribution of ticks and their relationship to different hosts, including wild animals, bats in particular. The present research was conducted at 16 localities throughout Serbia, Montenegro, Bosnia and Herzegovina, and Former Yugoslav Republic of Macedonia (FYROM). We examined 475 individuals of bats belonging to 13 species. A total of three tick species were identified, I. simplex being the most numerous and widespread, followed by I. vespertilionis and A. vespertilionis. To the best of our knowledge, the presented data include the first records of I. simplex in Serbia and Montenegro, I. vespertilionis for Montenegro and A. vespertilionis in FYROM. Also, we identify a new possible host/parasite association between I. simplex and Rhinolophus euryale.
Berger, K.A.; Ginsberg, Howard S.; Gonzalez, L.; Mather, T.N.
Laboratory studies have shown clear relationships between relative humidity (RH) and the activity and survival of Ixodes scapularis Say (blacklegged tick). However, field studies have produced conflicting results. We examined this relationship using weekly tick count totals and hourly RH observations at three field sites, stratified by latitude, within the state of Rhode Island. Records of nymphal tick abundance were compared with several RH-related variables (e.g., RH at time of sampling and mean weekly daytime RH). In total, 825 nymphs were sampled in 2009, a year of greater precipitation, with a weighted average leaf litter RH recorded at time of sampling of 85.22%. Alternatively, 649 nymphs were collected in 2010, a year of relatively low precipitation, and a weighted average RH recorded at time of sampling was 75.51%. Negative binomial regression analysis of tick count totals identified cumulative hours <82% RH threshold as a significant factor observed in both years (2009: P = 0.0037; 2010: P < 0.0001). Mean weekly daytime RH did not significantly predict tick activity in either year. However, mean weekly daytime RH recorded with 1-wk lag before sample date was a significant variable (P = 0.0016) in 2010. These results suggest a lag effect between moisture availability and patterns of tick activity and abundance. Differences in the relative importance of each RH variable between years may have been due to abnormally wet summer conditions in 2009.
Bello, Ana Cristina P De P; Da Cunha, Arildo P; Leite, Romário C; Oliveira, Paulo R; Ribeiro, Antônio Cândido C L; Domingues, Luisa N; De Freitas, Carolina Maria V; Bastianetto, Eduardo; Dalla Rosa, Ricardo C
This trial evaluated control practices of Anocentor nitens on equines, using spraying devices and application of acaricide paste formulation in the auricular pavilion and nasal diverticulum. The study was carried out from October 2003 to March of 2008 and the evaluations had been divided in the following stages: Phase 1--out/03 mar/04 and Phases 2, 3, 4 and 5, respectively, correspondents to the month's periods until março/08. It was used score of 0 to 3 to classify infestation levels. From abr/04 to mar/06 was implanted a schedule of acaricide sprayings every seven days and divided in two series. The first one beginning in April 2004 and the second beginning in July, both using six sprayings treatments with pyrethroid chemical base--cypermethrin 0,015%, plus topical treatments applied monthly in the auricular pavilions (powder acaricide). From abril/06 to março/08 was carried out similar schedule treatments, each two months, using an experimental acaricide paste in the auricular pavilion and nasal diverticulum. Phases 2 and 3 did not showed reduction of the parasitic loads of A. nitens compared to the control period. Whereas in Phases 4 and 5 registered significant reduction compared control period and also with the results of Phases 2 and 3, characterizing the effectiveness of the treatment with the acaricide paste formulation. Results demonstrated of A. nitens populations present in the nasal diverticulum are important in the maintenance of the infestations on equines, and necessary attention to this anatomical structure when controlling ticks.
Olwoch, J M; Van Jaarsveld, A S; Scholtz, C H; Horak, I G
The suitability of present and future climates for 30 Rhipicephalus species in Africa are predicted using a simple climate envelope model as well as a Division of Atmospheric Research Limited-Area Model (DARLAM). DARLAM's predictions are compared with the mean outcome from two global circulation models. East Africa and South Africa are considered the most vulnerable regions on the continent to climate-induced changes in tick distributions and tick-borne diseases. More than 50% of the species examined show potential range expansion and more than 70% of this range expansion is found in economically important tick species. More than 20% of the species experienced range shifts of between 50 and 100%. There is also an increase in tick species richness in the south-western regions of the sub-continent. Actual range alterations due to climate change may be even greater since factors like land degradation and human population increase have not been included in this modelling process. However, these predictions are also subject to the effect that climate change may have on the hosts of the ticks, particularly those that favour a restricted range of hosts. Where possible, the anticipated biological implications of the predicted changes are explored.
Chen, C; Munderloh, U G; Kurtti, T J
Three new cell lines, IDE8 and IDE12 from embryos of northern specimens of Ixodes scapularis Say and ISE18 from southern specimens of I. scapularis, were compared cytogenetically via conventional karyotyping, C- and G-banding, and nucleolar organizing regions (NORs). The karyotypes were very similar. The standard karyotype in the three cell lines consisted of 28 chromosomes with 26 autosomes and XX (female) or XY (male) sex chromosomes. The X chromosome was the largest, and the Y chromosome the smallest chromosome of the karyotype. Constitutive heterochromatin (C-bands) was almost entirely restricted to the centromeric region. An additional interstitial C-band in chromosome 7 was an important notable characteristic of the three cell lines. In sets showing a similar degree of condensation, individual chromosomes of the three lines had identical G-banding patterns. In addition, there was no difference among the cells in number and position of NORs. There were approximately 100 G-bands per haploid set in chromosomes from cells in metaphase, with three to 18 G-bands in each chromosome arm. After staining with silver nitrate, interstitial NORs were identified in chromosomes 7, 10, and the X chromosome. Male cells had five and female cells had six NORs. These findings support the notion that I. scapularis and I. dammini Spielman et al. are conspecific.
Chen, Ze; Li, Youquan; Ren, Qiaoyun; Liu, Zhijie; Luo, Jin; Li, Kai; Guan, Guiquan; Yang, Jifei; Han, Xueqing; Liu, Guangyuan; Luo, Jianxun; Yin, Hong
Haemaphysalis bispinosa Neumann has been considered to exist in China, especially in the southern part of the country. However, H. bispinosa referred to in many Chinese research papers may in fact be H. longicornis, which is widely distributed in most regions of China. In order to clarify the occurrence of H. bispinosa, Haemaphysalis ticks collected from 18 of 23 provinces of China (Hebei, Henan, Hubei, Guangxi, Gansu, Yunnan, Xinjiang, Anhui, Zhejiang, Shannxi, Guizhou, Sichuan, Shanxi, Shandong, Ningxia, Fujian, Qinghai and Jiangxi) were examined based on morphological and molecular characteristics. We found no evidence of H. bispinosa being present in China. Our results indicate that all of the so called "H. bispinosa" ticks reported in China are in fact H. longicornis.
Otranto, Domenico; Dantas-Torres, Filipe; Tarallo, Viviana Domenica; Ramos, Rafael Antonio do Nascimento; Stanneck, Dorothee; Baneth, Gad; de Caprariis, Donato
Certain tick species including Ixodes holocyclus can inoculate neurotoxins that induce a rapid, ascending flaccid paralysis in animals. Rhipicephalus sanguineus, the most widespread tick of dogs, is recognized as a vector of several pathogens causing diseases in dogs and humans. A single report suggests its role as cause of paralysis in dogs. This study presents the clinical history of 14 young dogs heavily infested by R. sanguineus (intensity of infestation, 63-328) in an endemic area of southern Italy. During May to June of 2011, dogs were presented at the clinical examination with neurological signs of different degrees (e.g., hind limb ataxia, generalized lethargy, and difficulty in movements). All animals were treated with acaricides and by manual tick removal but ten of them died within a day, displaying neurological signs. The other 4 dogs recovered within 3 days with acaricidal and supportive treatment. Twelve dogs were positive by blood smear examination for Hepatozoon canis with a high parasitemia, two also for Babesia vogeli and two were negative for hemoparasites. Low-grade thrombocytopenia, hypoalbuminemia, and pancytopenia were the haematological alterations most frequently recorded. Other causes of neurological disease in dogs were excluded and the diagnosis of tick paralysis by R. sanguineus was confirmed (ex juvantibus) by early and complete recovery of 4 dogs following acaricidal treatment and tick removal.
Operational Assessment Department, Navy Entomology Center of Excellence, Bldg. 937, Naval Air Station Jacksonville, Jacksonville, FL 32212. 2...ORGANIZATION NAME(S) AND ADDRESS(ES) Navy Entomology Center of Excellence,Operational Assessment Department,Bldg. 937, Naval Air Station,Jacksonville,FL,32212...Stafford 2007). 710 JOURNAL OF MEDICAL ENTOMOLOGY Vol. 51, no. 3 These synthetic pyrethroids could be useful for fo- cused suppression or exclusion of
Burkot, T. R.; Mullen, G. R.; Anderson, R.; Schneider, B. S.; Happ, C. M.; Zeidner, N. S.
Polymerase chain reaction analysis of 204 Amblyomma americanum and 28 A. maculatum ticks collected in August 1999 near the homes of patients with southern tick-associated rash illness and in control areas in Choctaw County, Alabama, showed Borrelia lonestari flagellin gene sequence from two adult A. americanum. The presence of B. lonestari in A. americanum ticks from Alabama suggests that this suspected pathogen may be widespread in the southeastern United States. PMID:11384533
Daemon, Erik; Maturano, Ralph; Monteiro, Caio Márcio de Oliveira; Goldner, Márcio Scoralik; Massoni, Tainara
The aim of this study was to assess the acaricidal activity of hydroethanolic formulations of thymol at varying concentrations on Rhipicephalus sanguineus and Dermacentor nitens larvae. The larval packet test was used and the thymol concentrations tested were 2.5, 5.0, 10.0, 15.0 and 20.0 mg/ml. The control group was exposed only to water and ethanol (50/50%) and there were 10 repetitions for each treatment. The mortality was evaluated after 24 h. For the R. sanguineus larvae, the mortality rates were 47.5, 50.2, 96.7, 95.9 and 98.1%, while for D. nitens the rates were 14.1, 75.0, 90.2, 90.3 and 99.5%, at respective thymol concentrations of 2.5, 5.0, 10.0, 15.0 and 20.0 mg/ml. The results indicate that the hydroethanolic formulations of thymol tested have acaricidal activity on R. sanguineus and D. nitens larvae exposed topically, causing mortality greater than 90% 24 h post-treatment starting at the concentration of 10 mg/ml.
Gibson, Amanda K; Smith, Zach; Fuqua, Clay; Clay, Keith; Colbourne, John K
Genomic resources within the phylum Arthropoda are largely limited to the true insects but are beginning to include unexplored subphyla, such as the Crustacea and Chelicerata. Investigations of these understudied taxa uncover high frequencies of orphan genes, which lack detectable sequence homology to genes in pre-existing databases. The ticks (Acari: Chelicerata) are one such understudied taxon for which genomic resources are urgently needed. Ticks are obligate blood-feeders that vector major diseases of humans, domesticated animals, and wildlife. In analyzing a transcriptome of the lone star tick Amblyomma americanum, one of the most abundant disease vectors in the United States, we find a high representation of unannotated sequences. We apply a general framework for quantifying the origin and true representation of unannotated sequences in a dataset and for evaluating the biological significance of orphan genes. Expressed sequence tags (ESTs) were derived from different life stages and populations of A. americanum and combined with ESTs available from GenBank to produce 14,310 ESTs, over twice the number previously available. The vast majority (71%) has no sequence homology to proteins archived in UniProtKB. We show that poor sequence or assembly quality is not a major contributor to this high representation by orphan genes. Moreover, most unannotated sequences are functional: a microarray experiment demonstrates that 59% of functional ESTs are unannotated. Lastly, we attempt to further annotate our EST dataset using genomic datasets from other members of the Acari, including Ixodes scapularis, four other tick species and the mite Tetranychus urticae. We find low homology with these species, consistent with significant divergence within this subclass. We conclude that the abundance of orphan genes in A. americanum likely results from 1) taxonomic isolation stemming from divergence within the tick lineage and limited genomic resources for ticks and 2) lineage
Background Genomic resources within the phylum Arthropoda are largely limited to the true insects but are beginning to include unexplored subphyla, such as the Crustacea and Chelicerata. Investigations of these understudied taxa uncover high frequencies of orphan genes, which lack detectable sequence homology to genes in pre-existing databases. The ticks (Acari: Chelicerata) are one such understudied taxon for which genomic resources are urgently needed. Ticks are obligate blood-feeders that vector major diseases of humans, domesticated animals, and wildlife. In analyzing a transcriptome of the lone star tick Amblyomma americanum, one of the most abundant disease vectors in the United States, we find a high representation of unannotated sequences. We apply a general framework for quantifying the origin and true representation of unannotated sequences in a dataset and for evaluating the biological significance of orphan genes. Results Expressed sequence tags (ESTs) were derived from different life stages and populations of A. americanum and combined with ESTs available from GenBank to produce 14,310 ESTs, over twice the number previously available. The vast majority (71%) has no sequence homology to proteins archived in UniProtKB. We show that poor sequence or assembly quality is not a major contributor to this high representation by orphan genes. Moreover, most unannotated sequences are functional: a microarray experiment demonstrates that 59% of functional ESTs are unannotated. Lastly, we attempt to further annotate our EST dataset using genomic datasets from other members of the Acari, including Ixodes scapularis, four other tick species and the mite Tetranychus urticae. We find low homology with these species, consistent with significant divergence within this subclass. Conclusions We conclude that the abundance of orphan genes in A. americanum likely results from 1) taxonomic isolation stemming from divergence within the tick lineage and limited genomic
Guzmán-Cornejo, Carmen; Robbins, Richard G.; Guglielmone, Alberto A.; Montiel-Parra, Griselda; Rivas, Gerardo; Pérez, Tila María
Abstract Distribution and host data from published literature and previously unpublished collection records are provided for all nine species of the Holarctic tick genus Dermacentor that are known to occur in Mexico, as well as two species that may occur there. Parasite-host and host-parasite lists are presented, together with a gazetteer of collection localities and their geographical coordinates. PMID:27110147
Guzmán-Cornejo, Carmen; Robbins, Richard G; Guglielmone, Alberto A; Montiel-Parra, Griselda; Rivas, Gerardo; Pérez, Tila María
Distribution and host data from published literature and previously unpublished collection records are provided for all nine species of the Holarctic tick genus Dermacentor that are known to occur in Mexico, as well as two species that may occur there. Parasite-host and host-parasite lists are presented, together with a gazetteer of collection localities and their geographical coordinates.
Nava, Santiago; Caparrós, José A; Mangold, Atilio J; Guglielmone, Alberto A
Ticks infesting humans were collected from September 2004 to August 2005 in Northwestern Córdoba in an area with a southern limit in the locality of Dean Funes (30 degrees 25'S 64 degrees 20'W) and San José de las Salinas (30 degrees 00'S 64 degrees 37'W) in the North. The collections consisted in ticks found attached on man obtained from three sources: 1) specimens fixed on two workers during two successive days per month of field work in the northern part of the area which belongs to Western Chaco district of the phytogeographical Chaco domain, 2) ticks attached to a man working in a farm close to Dean Funes in the Chaco Serrano district of the Chaco domain and, 3) ticks collected from a collaborator visiting daily a suburban property with dogs in the vicinities of Dean Funes. Most ticks collected were larvae, nymphs and adults of Amblyomma neumanni from the Chaco Serrano district where a nymph of Otobius megnini was also found on man. Adults of Amblyomma parvum and Amblyomma tigrinum were detected feeding on humans in the Western Chaco district and in the property close to Dean Funes, respectively. Amblyomma neumanni was absent on man from December to April while most specimens of A. parvum and A. tigrinum were collected during summer. Their role as potential vector of tick-transmitted diseases in the area is unknown.
Hoogstraal & Wassef, H. taiwana Sugimoto, H. yeni Toumanoff, Ixodes acutitarsus ( Karsch ), I. granulatus Supino, I. kuntzi Hoogstraal & Kohls, I...in the same five checklists. The senior synonym I. ovatus is listed only by Tseng Ixodes acutitarsus ( Karsch , 1880).8 (1978) and Hoogstraal (letter no
Baker, Anne S
Mites and ticks (Acari) have been found in a variety of archaeological situations. Their identification has enabled data on habitat and dietary preferences to be obtained, and these have been used to interpret study sites. Despite this, Acari are not routinely considered in analyses in the way that other environmental components are. Like forensic science, archaeology draws on biological material to rebuild past human activity, and acarology has the potential to provide a much greater amount of evidence to both than is currently the case. As an aid to workers in these fields, an overview is presented of the Acari that have been extracted from archaeological samples, the situations in which they were found and the contribution their presence can make to the interpretation of sites.
Borges, Lígia Miranda Ferreira; Li, Andrew Yongsheng; Olafson, Pia Untalan; Renthal, Robert; Bauchan, Gary Roy; Lohmeyer, Kimberly Hutchison; León, Adalberto Angel Pérez de
The present study was conducted to elucidate the neuronal pathways between peripheral olfactory and taste sensilla and the synganglion in an Ixodidae tick species. The tarsus of the front legs (olfactory nerves) and the fourth palpal segment (gustatory nerves) of unfed Amblyomma americanum males and females were excised. A neuronal tracer, dextran tetramethylrhodamine, was used for filling of the sensory neurons. The synganglion preparations were examined using a confocal microscope. Neuronal arborizations from the Haller's organ were confined to the olfactory lobes and the first pedal ganglion. The estimated number of olfactory glomeruli ranged from 16 to 22 per olfactory lobe in the females. The number of glomeruli was not counted in males because they were densely packed. Sensory neurons associated with sensilla at the distal end of the palpal organ projected into the palpal ganglion in the synganglion through the palpal nerve. Gustatory sensory neurons associated with palpal sensilla projected into a commissure with several bulges, which are confined in the palpal ganglion. The findings of distinct projection patterns of sensory neurons associated with the Haller's organ and palpal organ in the lone star tick from this study advanced our knowledge on mechanisms of sensory information processing in ticks.
Brown, D. J. F.; Halbrendt, J. M.; Robbins, R. T.; Vrain, T. C.
The transmission of North American nepoviruses by putative species belonging to the Xiphinema americanum-group is reviewed. Xiphinema americanum sensu stricto, X. californicum, and X. rivesi each transmit cherry rasp leaf (CRLV), tobacco ringspot (TobRSV), and tomato ringspot nepovirus (TomRSV), and X. bricolensis is a vector of TomRSV. The apparent lack of specificity in the transmission of North American nepoviruses by X. americanum-group species markedly contrasts with the specific associations between European nepoviruses and their vector nematode species. Two complementary projects are described examining the taxonomic identity of putative species in the X. americanum-group, their morphological and genetic relationships, their ontogeny, and their ability to transmit viruses. PMID:19279778
Jiang, Ju; Yarina, Tamasin; Miller, Melissa K; Stromdahl, Ellen Y; Richards, Allen L
A quantitative real-time polymerase chain reaction assay to detect and quantify a portion of the outer membrane protein B gene (ompB) of Rickettsia amblyommii was employed to assess the threat of R. amblyommii exposure to humans parasitized by Amblyomma americanum (the lone star tick). A total of 72 pools of lone star ticks removed from humans were acquired from two collections and used in this study: 44 pools of A. americanum submitted to the Department of Defense Human Tick Test Kit Program in 2003 collected from 220 individuals from 14 states, and 28 pools of A. americanum representing 120 ticks obtained from boy scouts and adult leaders at the Boy Scouts of America National Jamboree held at Fort A.P. Hill, Virginia, in 2005. Of the 72 lone star tick pools representing 340 lone star ticks, 58 pools (80.5%) were positive for R. amblyommii. In addition, individual A. americanum ticks parasitizing humans collected as part of the Department of Defense Human Tick Test Kit Program in 2002 and 2003 from 17 states were evaluated. It was found that 244 of 367 (66.5%) individual A. americanum ticks tested positive for the presence of R. amblyommii DNA. These results clearly show that lone star ticks parasitizing humans are highly infected with R. amblyommii, which may potentiate rickettsial infection of and possibly disease in humans.
Anderson, B E; Sims, K G; Olson, J G; Childs, J E; Piesman, J F; Happ, C M; Maupin, G O; Johnson, B J
Polymerase chain reaction primers specific for Ehrlichia chaffeensis were used to amplify DNA from extracts of pooled ticks. Amplification was performed on extracts from 140 pools (1,579 total ticks) consisting of three tick genera collected from five states. The characteristic 389-basepair product was observed after amplification of extracts from seven different pools of adult Amblyomma americanum (117 pools, 1,462 ticks), but not from pools of nymphs. No specific product was observed after amplification of 20 pools (105 ticks) of Dermacentor variabilis and three pools of Ixodes scapularis (12 ticks). Ehrlichia chaffeensis was present in A. americanum at a minimum frequency of > or = 0.48%, suggesting that A. americanum may be a vector of human ehrlichiosis.
Nancy Broshot; Lynn Larsen; Robert. Tinnin
Patterns of branch growth in Pinus contorta Dougl. ex Loud, (lodgepole pine) on the east side of the Cascade Range in Oregon were significantly altered by Arceuthobium americanum (lodgepole pine dwarf mistletoe). There were decreases in the number, length, and mass of needles, as well as in the length and mass of twigs. These...
Cohen, Sara B.; Yabsley, Michael J.; Garrison, Laurel E.; Freye, James D.; Dunlap, Brett G.; Dunn, John R.; Mead, Daniel G.; Jones, Timothy F.
To determine the geographic distribution of the newly recognized human pathogen Rickettsia parkeri, we looked for this organism in ticks from Tennessee and Georgia, USA. Using PCR and sequence analysis, we identified R. parkeri in 2 Amblyomma americanum ticks. This rickettsiosis may be underdiagnosed in the eastern United States. PMID:19788817
Varela, A S; Moore, V A; Little, S E
Amblyomma americanum (lone star tick) is known or suspected to vector several organisms that are implicated as human pathogens, including Ehrlichia chaffeensis, E. ewingii, and Borrelia lonestari. These three agents have also been detected in white-tailed deer (Odocoileus virginianus). Because northeastern Georgia has a high abundance of both lone star ticks and white-tailed deer, and one of these organisms, E. chaffeensis, is already known to be endemic in the area, we assayed individual adult A. americanum, collected during the spring of 2001, 2002, and 2003, for these three organisms. A total of 400 ticks were dissected and tissues assayed by polymerase chain reaction (PCR) using Ehrlichia species-specific and Borrelia genus-wide primers. Of ticks tested, 2.0% (8/398) had evidence of E. chaffeensis, 4.8% (19/398) had evidence of E. ewingii, and 1.0% (4/398) had evidence of B. lonestari. Borrelia sp. spirochetes were also visualized by an indirect fluorescent antibody test, using an anti-flagellin monoclonal antibody (H9724), in a total of 10.7% (32/300) of ticks tested in 2003. These results reconfirm the presence of E. chaffeensis and establish evidence of E. ewingii and B. lonestari in questing adult A. americanum ticks from northeastern Georgia. Detection of at least two of the three organisms in ticks collected each year suggests that people in northeastern Georgia are at risk of infection with these organisms.
Clemente, Mateus Aparecido; de Oliveira Monteiro, Caio Márcio; Scoralik, Márcio Goldner; Gomes, Fernando Teixeira; de Azevedo Prata, Márcia Cristina; Daemon, Erik
The present study evaluated the acaricidal activity of essential oils from Eucalyptus citriodora and Cymbopogon nardus on non-engorged larvae of Amblyomma cajennense and Anocentor nitens. In order to carry out the study, six groups were formed, each concentration being a treatment (6.25%, 12.5%, 25%, and 50%, respectively) and also with the creation of a control group (distilled water) and a positive control (Deltametrine). For each treatment, approximately 100 larvae of these ticks were placed onto filter papers (2 x 2 cm) impregnated with the concentrations used to test. Next, the envelopes were closed bearing inside the filter paper with measurements of 6 x 6 cm. For each group, six repetitions were performed, and after 24 h live and dead larvae were counted. This procedure was carried out for two essential oils on the two species of ticks. For A. cajennense, the acaricide efficacy of E. citriodora oil was of 10.8%, 35.3%, 34.5%, and 53.1%, whereas the efficacy of C. nardus was of 0.0%, 0.0%, 0.0%, and 61.1% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. In relation to A. nitens, the acaricide efficacy of E. citriodora oil was of 20.1%, 84.5%, 89.2%, and 100.0%, whereas the efficacy of C. nardus was of 0.0%, 90.8%, 100.0%, and 100.0% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. The results indicate that the essential oils tested showed a promising acaricidal activity mainly on A. nitens larvae.
Gomes, Geovany Amorim; Monteiro, Caio Márcio Oliveira; Julião, Lisieux de Santana; Maturano, Ralph; Senra, Tatiane Oliveira Souza; Zeringóta, Viviane; Calmon, Fernanda; Matos, Renata da Silva; Daemon, Erik; Carvalho, Mario Geraldo de
The aims of this work were to identify the compounds and to investigate the acaricidal activity of the essential oil of Lippia sidoides for unengorged larvae and nymphs of Rhipicephalus sanguineus and Amblyomma cajennense. The oil was analyzed by gas chromatography and gas chromatography/mass spectrometry. In total, 22 compounds comprising 98.5% of the total peak area were identified. The major constituent of the essential oil was thymol (69.9%). The acaricidal activity against larvae and nymphs was assessed using a modified larval packet test. In all experiments, oils were tested at concentrations of 2.35, 4.70, 9.40 14.10 and 18.80 mg/mL. The mortalities of larvae and nymphs of R. sanguineus were 20.6, 47.8, 73.6, 99.5 and 99.0% and 12.0, 50.0, 76.3, 96.0 and 96.1%, respectively. For larvae and nymphs of A. cajennense the rates of mortality were 41.9, 63.3, 77.8, 82.5 and 100.0% and 0.0, 32.8, 64.8, 71.1 and 94.0%, respectively. The LC 90 values of the L. sidoides oil were 11.56 and 12.97 mg/mL for larvae and nymphs of R. sanguineus and 15.70 and 18.52 mg/mL for larvae and nymphs of A. cajennense, respectively. The essential oil from L. sidoides has acaricidal activity on unengorged larvae and nymphs of R. sanguineus and A. cajennense.
Cruz, Paula Barroso; Barbosa, Alan Franco; Zeringóta, Viviane; Melo, Diego; Novato, Tatiane; Fidelis, Queli Cristina; Fabri, Rodrigo Luiz; de Carvalho, Mário Geraldo; Oliveira Sabaa-Srur, Armando Ubirajara; Daemon, Erik; Monteiro, Caio Márcio Oliveira
We evaluated the acaricidal activity of Acmella oleracea methanol extract and spilanthol on Rhipicephalus microplus and Dermacentor nitens. The extract was made through maceration with methanol. From this extract, a dichloromethane fraction with 99% spilanthol was obtained and tested on R. microplus larvae and engorged females and D. nitens larvae. For evaluation against larvae, the modified larval packet test was used, and both the methanol extract and dichloromethane fraction were tested at concentrations of 0.2-50mg/mL. The modified larval packet test was also used in the lethal time (LT) test, with the methanol extract at a concentration of 12.5mg/mL and the percentage mortality was assessed after 15, 30, 45, 60, 75, 90, 120min and 24h. The 50% lethal time calculation (LT50) was performed in this test. The engorged female test was performed with R. microplus only, at concentrations of 25-200mg/mL for methanol extract and 2.5-20.0mg/mL for spilanthol. The methanol extract caused 100% mortality of the R. microplus and D. nitens larvae at concentrations of 3.1 and 12.5mg/mL, respectively. Spilanthol resulted in 100% mortality of R. microplus larvae at concentration of 1.6mg/mL and of D. nitens at 12.5mg/mL. In the lethal time assay using the methanol extract, the mortality rate was 100% for R. microplus and D. nitens larvae after 120min and 24h, with LT50 values of 38 and 57min, respectively. In the test of females, the egg mass weight and the hatching percentage of the groups treated with concentrations equal to or higher than 50.0mg/mL of methanol extract were significantly reduced (p<0.05), while for spilanthol, the reduction of the egg mass weight and hatching percentage occurred from concentrations of 10.0mg/mL and 2.5mg/mL, respectively. Females treated with 200.0mg/mL of extract died before starting oviposition, resulting in 100% effectiveness, while the best efficacy for spilanthol was 92.9% at a concentration of 20.0mg/mL. Thus we conclude that the methanol extract of A. oleracea and spilanthol have acaricidal activity against R. microplus and D. nitens.
Novato, Tatiane Pinheiro Lopes; Araújo, Laryssa Xavier; de Monteiro, Caio Márcio Oliveira; Maturano, Ralph; Senra, Tatiane de Oliveira Souza; da Silva Matos, Renata; Gomes, Geovany Amorim; de Carvalho, Mario Geraldo; Daemon, Erik
This study aimed at assessing the combined effect of thymol, carvacrol and (E)-cinnamaldehyde on Amblyomma sculptum and Dermacentor nitens larvae. The effects resulting from treatments were evaluated by means of the modified larval packet test. In order to determine the LC50, components of essential oils, the monoterpenes thymol, carvacrol and phenylpropanoid (E)-cinnamaldehyde were individually tested at different concentrations. After determining the LC50, each essential oil component was separately evaluated and then combined with another substance at a 1:1 proportion at the LC50 concentration and at 1/2 and 1/4 of the LC50. For A. sculptum, the lowest LC50 value was obtained for (E)-cinnamaldehyde (1.40 mg/ml), followed by thymol (2.04 mg/ml) and carvacrol (3.49 mg/ml). The same order of effectiveness was observed for D. nitens, with values of 1.68, 2.17 and 3.33 mg/ml, respectively. In the evaluation of component associations of essential oils against A. sculptum larvae, only the combinations between carvacrol and thymol (LC50) and carvacrol and (E)-cinnamaldehyde (1/4 LC50) presented a moderate synergetic effect. In turn, for D. nitens larvae, the combinations between thymol and carvacrol (LC50 and 1/2 LC50) presented a synergetic effect, while the others presented an additive or antagonistic effect. Therefore, it can be concluded that the combination of thymol and carvacrol (LC50) has a moderate synergetic effect against A. sculptum larvae, while thymol, combined with carvacrol (LC50 and 1/2 LC50), has a synergetic effect against D. nitens larvae.
Chemical composition and acaricidal activity of essential oil from Lippia sidoides on larvae of Dermacentor nitens (Acari: Ixodidae) and larvae and engorged females of Rhipicephalus microplus (Acari: Ixodidae).
Gomes, Geovany Amorim; Monteiro, Caio Márcio de Oliveira; Senra, Tatiane de Oliveira Souza; Zeringota, Viviane; Calmon, Fernanda; Matos, Renata da Silva; Daemon, Erik; Gois, Roberto Wagner da Silva; Santiago, Gilvandete Maria Pinheiro; de Carvalho, Mario Geraldo
The aim of this work was to identify the compounds and to investigate the acaricidal activity of the essential oil from the leaves of Lippia sidoides on Rhipicephalus microplus and Dermacentor nitens. The oil was obtained by hydrodistillation and analyzed by gas chromatography (GC/FID) and gas chromatography/mass spectrometry. In total, 15 compounds comprising 99.97 % of the total peak area were identified. The main constituent of the essential oil was thymol (67.60 %). The acaricidal activity was assessed by the modified larval packet test, with oil concentrations of 2.5, 5.0, 10.0, 15.0, and 20.0 μl/ml, and by the female immersion test with concentrations of 10.0, 20.0, 40.0, 60.0, and 80.0 μl/ml. The mortality of the R. microplus and D. nitens larvae was greater than 95 % starting at concentrations of 10.0 and 20.0 μl/ml, respectively. In the test with the engorged females, the L. sidoides essential oil starting at a concentration of 40.0 μl/ml caused a significant reduction (p < 0.05) in the values of the egg mass weight and egg production index. The viability of the eggs was affected in all the treated groups, with significantly lower hatching rates (p < 0.05) in relation to the control group. The control percentages at concentrations of 10.0, 20.0, and 30.0 μl/ml were 54, 57, and 72 %, and reached 100 % at the highest two concentrations (60.0 and 80.0 μl/ml). Therefore, it can be concluded that the essential oil from the leaves of L. sidoides has acaricidal activity on R. microplus and D. nitens.
Lazarova, Stela S.; Malloch, Gaynor; Oliveira, Claudio M.G.; Hübschen, Judith; Neilson, Roy
The 18S ribosomal DNA (rDNA) and cytochrome oxidase I region of mitochondrial DNA (mtDNA) were sequenced for 24 Xiphinema americanum-group populations sourced from a number of geographically disparate locations. Sequences were subjected to phylogenetic analysis and compared. 18S rDNA strongly suggested that only X. pachtaicum, X. simile (two populations) and a X. americanum s.l. population from Portugal were different from the other 20 populations studied, whereas mtDNA indicated some heterogeneity between populations. Phylogenetically, based on mtDNA, an apparent dichotomy existed amongst X. americanum-group populations from North America and those from Asia, South America and Oceania. Analyses of 18S rDNA and mtDNA sequences underpin the classical taxonomic issues of the X. americanum-group and cast doubt on the degree of speciation within the X. americanum-group. PMID:19259456
Feather mites (Acari: Astigmata) were analyzed with low temperature scanning electron microscopy (LT-SEM), including the description of three new species: Plicatalloptes atrichogynus sp. nov. (Analgoidea: Alloptidae) from the Neotropical cormorant Phalacrocorax brasilianus (Gmelin, 1789) (Pelecanifo...
Garcia, Marcos V; Matias, Jaqueline; Aguirre, AndrÉ De A R; Csordas, Barbara G; SzabÓ, Matias P J; Andreotti, Renato
Identifying the tick species that successfully feed on humans would increase knowledge of the epidemiology of several tick-borne diseases. These species salivate into the host, increasing the risk of pathogen transmission. However, there is a lack of data in the literature regarding the ticks that prefer to feed on humans. Herein, we describe the successful feeding of Amblyomma coelebs Neumann nymphs on two of the authors after accidental tick bites occurred during field surveys in two preserved areas of Mato Grosso do Sul, Brazil. One of the host-parasite interactions was closely monitored, and the tick development, gross host skin alterations, and related sensations are presented.
Miller, R J; Davey, R B; George, J E
Two patterns of pyrethroid resistance were characterized from Boophilus microplus (Canestrini) collected in Mexico. One was characteristic of a kdr mutation and the other involved esterase and cytochrome P450 enzyme systems. Very high resistance to permethrin, cypermethrin, and flumethrin, not synergized by TPP and PBO and high resistance to DDT, characterized the kdr-like pattern found in the Corrales and San Felipe strains. Esterase and cytochrome P450-dependent resistance was found in the Coatzacoalcos strain. It was characterized by resistance to permethrin, cypermethrin, and flumethrin, synergized by TPP and PBO, but no resistance to DDT. The Coatzacoalcos strain also showed 3.6-fold resistance to the organophosphate coumaphos. This factor appeared to be independent of pyrethroid resistance. Pyrethroid resistance patterns found in Mexico were similar to those found earlier in Australia. The significance of pyrethroid and coumaphos resistance to the U.S. cattle fever tick quarantine is discussed.
Guerrero, Felix D; Li, Andrew Y; Hernandez, Ruben
Polymerase chain reaction (PCR) diagnostic assays were used to identify possible resistance-associated roles of two amino acid substitutions found in pyrethroid resistance-associated genes of Boophilus microplus (Canestrini). Individual larvae from the San Felipe target site resistant strain and the Coatzacoalcos (Cz) metabolic resistant strain were separated into resistant and susceptible groups by larval packet bioassays and analyzed by PCR. A Phe --> Ile amino acid mutation in the sodium channel gene S6 transmembrane segment of domain III was found to have a close association with survival of acaricide treatments containing as high as 30% permethrin. As the permethrin dose was increased, an increase was seen in the proportion of surviving larvae that possessed two mutated sodium channel alleles. An Asp --> Asn amino acid substitution, originally found in high allele frequency in alleles of the CzEst9 esterase of the Cz strain, appeared to provide some resistance to permethrin. However, the presence of the mutation did not associate with resistance in the dose-response fashion seen with the sodium channel amino acid mutation. Resistance provided by CzEst9 might be more dependent on concentration of CzEst9 more so than the presence of a mutated allele.
Flores, Fernando S; Nava, Santiago; Batallán, Gonzalo; Tauro, Laura B; Contigiani, Marta S; Diaz, Luis A; Guglielmone, Alberto A
Ixodid ticks were collected from wild birds in five ecoregions in north-central Argentina, namely: Selva de las Yungas, Esteros del Iberá, Delta e Islas del Paraná, Selva Paranaense and Chaco Seco. A total of 2199 birds belonging to 139 species, 106 genera, 31 families and 11 orders were captured, but ticks were collected only from 121 birds (prevalence=5.5%) belonging to 39 species (28.1%) and three Orders: Tinamiformes (Tinamidae) and Falconiformes (Falconidae) in Selva de las Yungas and Passeriformes (Conopophagidae, Corvidae, Emberizidae, Furnariidae, Icteridae, Parulidae, Thamnophilidae, Thraupidae, Troglodytidae, Turdidae) for all ecoregions. The following tick species were found: Haemaphysalis juxtakochi, Haemaphysalis leporispalustris, Ixodes pararicinus plus Amblyomma sp. and Haemaphysalis sp. in Selva de las Yungas; Amblyomma triste and Ixodes auritulus in Delta e Islas del Paraná; Amblyomma dubitatum, A. triste and Amblyomma sp. in Esteros del Iberá; Amblyomma ovale and Amblyomma sp. in Selva Paranaense, and Amblyomma tigrinum in Chaco Seco. Amblyomma dubitatum was found for the first time on Passeriformes, while the records of A. ovale on avian hosts are the first for Argentina. Birds are also new hosts for I. pararicinus females. Besides 2 larvae and 1 nymph, and 1 larvae found on Tinamidae (Tinamiformes) and Falconidae (Falconiformes), respectively, all other ticks (691 larvae, 74 nymphs and 2 females) were found on Passeriformes with a relevant contribution of the family Turdidae. Birds are important hosts for I. pararicinus as shown by a prevalence of 45% while all others prevalence were below 15%. All the species of Amblyomma and Haemaphysalis found on birds in Argentina have been also detected on humans and are proven or potential vectors for human diseases. Therefore, their avian hosts are probable reservoirs of human pathogens in Argentina. Copyright © 2014 Elsevier GmbH. All rights reserved.
Aboelhadid, Shawky Mohamed; Mahran, Hesham A; El-Hariri, Hazem M; Shokier, Khalid Mohamed
Background: Several compounds obtained from plants have potential insecticidal, growth deterrent or repellent characteristics. The control of hard ticks by non-chemical substances was targeted in this study. Methods: The effect of 36 materials on in-vitro ticks was studied, including 2 absolute controls (water only or absolute ethyl alcohol only), 6 conventionally used spinosad preparations (aqueous solutions), 12 Nigella sativa (N. sativa) preparations (aqueous and alcoholic solutions), and 12 Thyme preparations (aqueous and alcoholic solutions). The engorged ticks were tested in-vitro for mortality and oviposition ability using the studied materials. Results: The final mortality after 48 hours of application in N. sativa aqueous preparations began from 10.0% concentration, 1.0% to 100% by concentration preparations ≥10%. In addition, N. sativa alcoholic preparations began from 50.0% concentration, 2 % to 100% by concentration ≥5%. Meanwhile, Thyme aqueous and alcoholic preparations began from 70.0% concentration, 5% to 90% by concentration 10–20%. Additionally, spinosad aqueous preparations and both of control preparations (Water and Alcohol) resulted in no mortality. All differences were statistically significant. The oviposition was stopped in N. sativa (aqueous ≥10% and alcoholic ≥5%) and in spinosad (aqueous≥25%). The aqoues dilution of the used matters killed B. annulatus larvae beginning from the concentration 5%. Conclusion: Nigella sativa alcohol 20% was the best of studied preparations being the lowest concentration (20%) that could achieve the highest lethal (100%) effect in shortest time (12 hours). Moreover, Thyme oil and spinosad could not kill 100% of adult but did on larvae. PMID:27308273
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...
Lubelczyk, C; Cahill, B K; Hanson, T; Turmel, J; Lacombe, E; Rand, P W; Elias, S P; Smith, R P
In July 2008, owners of seasonal camps in Vermont and Maine were exposed to large numbers of questing ticks after opening their camps for the season. Examination of collected specimens revealed that the camp in Vermont was infested with Ixodes cookei Packard, and the camp in Maine was infested with Ixodes marxi Banks. In both instances, numerous tick bites were reported by residents. Both camps were also occupied by wildlife during the off-season, primarily squirrels (Maine) and skunks (Vermont). Subsequent samples from the Vermont site were tested for the presence of Powassan encephalitis virus, though no viral activity was detected.
Pat-Nah, Henry; Rodriguez-Vivas, Roger Ivan; Bolio-Gonzalez, Manuel Emilio; Villegas-Perez, Sandra Luz; Reyes-Novelo, Enrique
Ehrlichia canis is the etiological agent behind canine monocytic ehrlichiosis, and the tick Rhipicephalus sanguineus (Latreille) is its main vector. Blood smear and nested polymerase chain reaction (PCR) techniques were used to identify E. canis infection in dogs and R. sanguineus, and explore factors possibly associated with infection in dogs in Yucatan, Mexico. Blood samples were taken and ticks R. sanguineus collected from 50 dogs (10 house dogs and 40 in an animal control center). Data were collected on dog age, sex, body condition, and signs associated with platelet deficiencies (epistaxis). Blood smears were analyzed to identify E. canis morulae and generate platelet counts. Nested PCR analysis was done on blood samples and 200 ticks. A χ(2) test was done to identify factors associated with the E. canis infection in the tested dogs. The overall prevalence for infection, as determined by PCR, was 36% (18 out of 50). All positive dogs were from samples collected from the animal shelter, representing prevalence, for this sampling site, of 45% (18 out of 40). Morulae in monocytes were identified in only 4% of samples. Dog origin (i.e. animal control center) was the only variable associated with E. canis infection (P < 0.01). Male ticks had a higher (P < 0.05) infection rate than female ticks (24.5 vs 13.5%). It is concluded that E. canis infection is present in both dogs and the brown dog ticks R. sanguineus in Yucatan, Mexico.
Allerdice, Michelle E J; Hecht, Joy A; Karpathy, Sandor E; Paddock, Christopher D
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.
Sréter-Lancz, Zsuzsa; Tornyai, Krisztián; Széll, Zoltán; Sréter, Tamás; Márialigeti, Károly
Fleas (95 Pulex irritans, 50 Ctenocephalides felis, 45 Ctenocephalides canis) and ixodid ticks (223 ixodes ricinus, 231 Dermacentor reticulatus, 204 Haemaphysalis concinna) were collected in Hungary and tested, in assays based on PCR, for Bartonella infection. Low percentages of P. irritans (4.2%) and C. felis (4.0%) were found to be infected. The groEL sequences of the four isolates from P. irritans were different from all the homologous sequences for bartonellae previously stored in GenBank but closest to those of Bartonella sp. SE-Bart-B (sharing 96% identities). The groEL sequences of the two isolates from C. felis were identical with those of the causative agents of cat scratch disease, Bartonella henselae and Bartonella clarridgeiae, respectively. The pap31 sequences of B. henselae amplified from Hungarian fleas were identical with that of Marseille strain. No Bartonella-specific amplification products were detected in C. canis, I. ricinus, D. reticulatus and H. concinna pools.
Martins, Thiago F; Gianizella, Sérgio L; Nunes, Pablo H; Faria, Diogo C L O; Do Nascimento, Carlos A R; Abrahão, Carlos R; Miranda, Flávia R; Teixeira, Rodrigo H F; Ramirez, Diego G; Barros-Battesti, Darci M; Labruna, Marcelo B
Since its original description from the Amazonian region, the tick species Amblyomma goeldii Neumann, 1899 has been misidentified with Amblyomma rotundatum Koch, 1844 in different countries of the Neotropical region. Because of this, some authors have considered that the only confirmed records of A. goeldii were from French Guyana. Herein, we reviewed all specimens of A. goeldii that have been deposited at two tick collections in Brazil. In addition, we describe the nymphal stage of A. goeldii for the first time. A total of 10 unpublished records of the adult stage of A. goeldii are recorded from the Amazonian region of Brazil, confirming the occurrence of A. goeldii in this country. Except for one record on the snake Boa constrictor Linnaeus, all records of A. goeldii reported in the present study were from anteaters (Pilosa: Myrmecophagidae). Our results, in conjunction with previous literature records, indicate that anteaters and large snakes are important hosts for the adult stage of A. goeldii. The nymph of A. goeldii is morphologically similar to the nymphs of Amblyomma romitii Tonelli-Rondelli, 1939, Amblyomma dissimile Koch, 1844, and A. rotundatum. We present a modification of a previously published taxonomic key of Amblyomma nymphs from Brazil, in order to perform taxonomic identification of the nymph of A. goeldii based on external morphology. The geographical distribution of A. goeldii appears to be restricted to the Amazonian region. There were no previous host records for the immature stages of A. goeldii, thus it is expected that the present nymphal description will facilitate further works on the ecology of this poorly studied tick species.
en Peligro de Extinción. Comisión Nacional para el Cono- cimiento y Uso de la Biodiversidad , Fondo de Cultura Económica, Instituto de Ecología, UNAM... Biodiversidad y Fondo de Cultura Económica, México, D. F. 981 pp. Chavarría, C.M. (1941) Garrapatas determinadas en México. Caracteres genéricos de las más...Campos, G. (2000) Biodiversidad de los ácaros en México. Fideicomiso Fondo para la Biodiver- sidad, México D. F., 230 pp. Hooker, W.A., Bishopp, F.C
Revista Mexicana de Biodiversidad 81: 289- 298, 2010 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection...I. tovari Revista Mexicana de Biodiversidad 80: 289- 298, 2010 291 19. Auriculae broadly rounded...Cornua and auriculae absent; hypostome Christmas tree-shaped, dentition 3/3; coxa Revista Mexicana de Biodiversidad 80: 289- 298, 2010
Aboelhadid, Shawky Mohamed; Mahran, Hesham A; El-Hariri, Hazem M; Shokier, Khalid Mohamed
Several compounds obtained from plants have potential insecticidal, growth deterrent or repellent characteristics. The control of hard ticks by non-chemical substances was targeted in this study. The effect of 36 materials on in-vitro ticks was studied, including 2 absolute controls (water only or absolute ethyl alcohol only), 6 conventionally used spinosad preparations (aqueous solutions), 12 Nigella sativa (N. sativa) preparations (aqueous and alcoholic solutions), and 12 Thyme preparations (aqueous and alcoholic solutions). The engorged ticks were tested in-vitro for mortality and oviposition ability using the studied materials. The final mortality after 48 hours of application in N. sativa aqueous preparations began from 10.0% concentration, 1.0% to 100% by concentration preparations ≥10%. In addition, N. sativa alcoholic preparations began from 50.0% concentration, 2 % to 100% by concentration ≥5%. Meanwhile, Thyme aqueous and alcoholic preparations began from 70.0% concentration, 5% to 90% by concentration 10-20%. Additionally, spinosad aqueous preparations and both of control preparations (Water and Alcohol) resulted in no mortality. All differences were statistically significant. The oviposition was stopped in N. sativa (aqueous ≥10% and alcoholic ≥5%) and in spinosad (aqueous≥25%). The aqoues dilution of the used matters killed B. annulatus larvae beginning from the concentration 5%. Nigella sativa alcohol 20% was the best of studied preparations being the lowest concentration (20%) that could achieve the highest lethal (100%) effect in shortest time (12 hours). Moreover, Thyme oil and spinosad could not kill 100% of adult but did on larvae.
Sampieri, B R; Furquim, K C S; Nunes, P H; Camargo-Mathias, M I
Tick control has been accomplished through the use of synthetic acaricides, which has created resistant individuals, as well as contaminating the environment and nontarget organisms. Substances of plant origin, such as oils and extracts of eucalyptus and neem leaves, have been researched as an alternative to replace the synthetic acaricides. Ricinoleic acid esters from castor oil have recently been shown as a promising alternative in eliminating bacterial contamination during ethanol fermentation, by acting as an effective biocide. The same positive results have been observed when these esters are added to the food given to tick-infested rabbits. This study tested the effect of these substance on the reproductive system of Rhipicephalus sanguineus females, added to rabbit food, more specifically on oogenesis. For this, four groups were established: four control groups (CG1, CG2, CG3, and CG4) and four treatment groups (TG1, TG2, TG3, and TG4) with one rabbit in each (New Zealand White), used as hosts. After full 4 days feeding (semi-engorgement), the females were collected and had their ovaries extracted. In this study, it was observed that R. sanguineus females exposed to esters had their ovaries modified, which was demonstrated through transmission electron microscopy techniques. The addition of ricinoleic esters to the diet of tick-infested rabbits revealed how toxic such substances are for the cytoplasmic organelles of oocytes and pedicel cells. These compounds can change the morphophysiology of germ and somatic cells, consequently influencing their viability and, therefore, confirming that the ricinoleic acid esters from castor oil are a promising substance in the control of R. sanguineus.
da Silva Matos, Renata; Daemon, Erik; Camargo-Mathias, Maria Izabel; Furquim, Karim Christina Scopinho; Sampieri, Bruno Rodrigues; Remédio, Rafael Neodini; Araújo, Laryssa Xavier; Novato, Tatiane Pinheiro Lopes
Thymol is a monoterpene with proven acaricide action for several tick species. In addition to killing these ectoparasites, thymol can also reduce oviposition and egg hatch rate. However, the effects of thymol on the morphophysiology of tick ovaries are still unknown. Thus, the aim of this study was to evaluate the morphophysiological changes caused by this active principle in ovaries of Rhipicephalus sanguineus after a 6-day feeding period, through the application of morphohistochemical techniques. After the feeding period, a total of 50 females were divided into five groups and immersed in the following solutions: (I) distilled water (control), (II) 30% ethanol (control), (III) 1.25 mg/mL thymol, (IV) 2.5 mg/mL thymol, and (V) 5.0 mg/mL thymol. The experimental groups were kept in a climatic chamber (27 ± 1 °C; RH 80 ± 10%) for 5 days. After this period, morphological (hematoxylin/eosin) and histochemical (von Kossa) techniques were applied after remotion of the ovaries. The morphological results revealed large vacuoles in germ cells at different developmental stages and invaginations that represent deformations in the chorionic membrane. From the results obtained in this study, it was concluded that thymol interfered with the development of oocytes, which showed degeneration signs. The treatment containing 5.0 mg/mL thymol affected more accentuately the morphological development. Moreover, thymol also altered the calcium content of yolk granules, which generally showed an intense staining for this element.
Arnosti, André; Brienza, Paula Desjardins; Furquim, Karim Christina Scopinho; Chierice, Gilberto Orivaldo; Neto, Salvador Claro; Bechara, Gervásio Henrique; Sampieri, Bruno Rodrigues; Camargo-Mathias, Maria Izabel
This study showed the interference of esters extracted from Ricinus communis in the secretory cycle of salivary glands of Rhipicephalus sanguineus ticks, which consequently caused collateral effects on their feeding process. Ticks attached on hosts which were fed with commercial feed containing different concentrations of R. communis oil esters suffered damages such as cytoplasmic changes in their salivary glands, notably in the acinar cells, impairing the functioning of the acini and accelerating the organs degeneration as a whole. It was found that esters interfered with the activity of cellular secretion by changing the glycoprotein of salivary composition especially in acini II cells. It was also shown that the damages caused by esters in the salivary glands cells of these ectoparasites increased in higher concentrations of the product and degenerative glandular changes were more pronounced.
Ogrzewalska, Maria; Literák, Ivan; Capek, Miroslav; Sychra, Oldřich; Calderón, Víctor Álvarez; Rodríguez, Bernardo Calvo; Prudencio, Carlos; Martins, Thiago F; Labruna, Marcelo B
The aim of this study was to document the presence of Rickettsia spp. in ticks parasitizing wild birds in Costa Rica. Birds were trapped at seven locations in Costa Rica during 2004, 2009, and 2010; then visually examined for the presence of ticks. Ticks were identified, and part of them was tested individually for the presence of Rickettsia spp. by polymerase chain reaction (PCR) using primers targeting fragments of the rickettsial genes gltA and ompA. PCR products were DNA-sequenced and analyzed in BLAST to determine similarities with previously reported rickettsial agents. A total of 1878 birds were examined, from which 163 birds (9%) were infested with 388 ticks of the genera Amblyomma and Ixodes. The following Amblyomma (in decreasing order of abundance) were found in immature stages (larvae and nymphs): Amblyomma longirostre, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma sabanerae, Amblyomma varium, Amblyomma maculatum, and Amblyomma ovale. Ixodes ticks were represented by Ixodes minor and two unclassified species, designated here as Ixodes sp. genotype I, and Ixodes sp. genotype II. Twelve of 24 tested A. longirostre ticks were found to be infected with 'Candidatus Rickettsia amblyommii', and 2 of 4 A. sabanerae were found to be infected with Rickettsia bellii. Eight of 10 larval Ixodes minor were infected with an endosymbiont (a novel Rickettsia sp. agent) genetically related to the Ixodes scapularis endosymbiont. No rickettsial DNA was found in A. calcaratum, A. coelebs, A. maculatum, A. ovale, A. varium, Ixodes sp. I, and Ixodes sp. II. We report the occurrence of I. minor in Costa Rica for the first time and a number of new bird host-tick associations. Moreover, 'Candidatus R. amblyommii' and R. bellii were found in A. longirostre and A. sabanerae, respectively, in Costa Rica for the first time.
Carroll, J.F.; Russek-Cohen, E.; Nichols, J.D.; Hines, J.E.
We conclude a mark-recapture study in which drag-collected ticks were removed from some park trails weekly from April to July. Weekly survival rates (probability of surviving and remaining on the trails) were significantly lower on trials used heavily by hikers, horses, and pets than on trails used less frequently. Although usage was the only obvious difference among these trails, differences in weekly survival rate estimates may be attributable to differential success in acquiring hosts. The estimated probability of capturing a host-seeking tick located along a trail on a single drag was 0.20 on the drag alone, and 0.25 including the person dragging. When routes parallel to the trails and of equal lengths were dragged immediately after sampling the trails, only .apprxeq. 5% as many ticks (including ticks on the person dragging) were found off the trails as on them. We found no evidence of reduced tick numbers on removal trails, but this result should be considered inconclusive because the power of the discerning test was low. However, the data reported here provide insights into turnover rates of the adult Dermacentor variabilis population and effectiveness of the drag as a sampling device.
Ahanger, R R; Godara, R; Katoch, R; Yadav, A; Bhutyal, A D S; Katoch, M; Singh, N K; Bader, M A
Detection of resistance levels against deltamethrin in Rhipicephalus (Boophilus) microplus collected from six districts of Jammu and Kashmir (India) was carried out using the adult immersion test. The regression graphs of probit mortality of ticks plotted against log values of concentration of drug were utilised for the determination of slope of mortality, lethal concentration for 50% (LC50), 95% (LC95) and resistance factor (RF). On the basis of the data generated on mortality, egg mass weight, reproductive index and percentage inhibition of oviposition, the resistance level was categorised as I, II, III and IV. Out of these six districts, resistance to deltamethrin at level I was detected in one district (RF = 1.9), at level II in two districts (RF = 7.08-10.07) and at level IV in three districts (RF = 96.08-288.72). The data generated on deltamethrin resistance status will help in formulating tick control strategy in the region.
grasshopper warbler , Locustella ochotensis (Middendorff), near Yasugi on 21 September 1991. Kakuda et al. (1989) collected H. phasiana from Kyushu...deciduous understory and shrubs were noted during 34% of the collections. Pine, oriental arborvitae, and deciduous leaf litter (from understory in pine...emerging through leaf litter was noted during 6% of the collections. One Jeju site, which represented 32% of the H. phasiana positive drags (43% of H
Tolesano-Pascoli, Graziela; Garcia, Frederico Innecco; Gomes, Carla Raphaela Gonzaga; Diniz, Kátia Cristina; Onofrio, Valeria Castilho; Venzal, José Manuel; Szabó, Matias Pablo Juan
Brazil harbors five species of Cypseloidinae swifts. Those from Streptoprocne and Cypseloides genera have a very distinct ecology. They shelter at night and build nests in moist cliffs by waterfalls. Information about tick infestation of these birds is virtually non-existent and restricted to the description of a new species, Ixodes paranaensis, in Streptoprocne biscutata in Paraná State and another record of this species in Streptoprocne zonaris in Minas Gerais State. We herein report tick infestation of swifts at eight waterfalls in the Cerrado biome of Minas Gerais State, southeastern Brazil. Swifts were captured during six campaigns from November 2008 to April 2013. Overall, 584 swifts were captured (527 C. senex, four C. fumigatus and 53 S. zonaris). Four birds were tick infested (prevalence of 0.7 %). Three individuals of C. senex hosted one tick each; a nymph of I. paranaensis, a female of I. paranaensis and a nymph of Amblyomma cajennense. One S. zonaris hosted an I. paranaensis nymph and an Ornithodoros sp. larva (Argasidae).
Some natural and unusual transfers of exotic ticks on hosts have been noticed in Poland. Reptiles together with migratory birds and migrating mammals, are the groups of vertebrates that transfer unknown tick species to the territory of Poland. The majority of exotic reptiles brought to Poland for breading and commercial purpose are infested by ticks. Therefore the systematic list of ticks as well as their geographical distribution in the world, tick-host specificity, characteristic and morphological description of genera/species are presented. The described species are as follow: Amblyomma exornatum, Amblyomma flavomaculatum, Amblyomma latum, Amblyomma nuttalli, Amblyomma quadricavum, Amblyomma sphenodonti, Amblyomma transversale, Amblyomma varanense, Hyalomma aegyptium. It is important to monitor occurrence of unknown tick species on hosts in Poland. Ticks parasitizing on reptiles are known as vectors of tick-borne diseases, which indicate a serious epidemic problem, created by the import of exotic reptiles to the territory of Poland.
Carnohan, Lucas P; Kaufman, Phillip E; Allan, Sandra A; Gezan, Salvador A; Weeks, Emma N I
The brown dog tick, Rhipicephalus sanguineus (Latrielle), can be a serious residential pest due to its unique ability, among ticks, to complete its lifecycle indoors. A single engorged and fertilized female tick can oviposit around 4,000 eggs, allowing indoor establishment to be rapid and easy to miss in early-stage infestations. Acaricide treatment is currently the primary method of control, but can be costly and can lead to the development of acaricide resistance in tick populations. Traps of various designs can be used to help monitor and manage populations of indoor pests, such as cockroaches and bed bugs, but there are currently no commercially available traps for use with brown dog tick infestations. This study included a comparison of four commercially available bed bug traps (NightWatch [BioSensory Inc., Putnam, CT], Bed Bug Beacon [PackTite, Fort Collins, CO], ClimbUp [Susan McKnight Inc., Memphis, TN], and Verify [FMC Corporation, Philadelphia, PA]) with regard to their efficacy in capturing brown dog ticks, and also compared tick attraction to ClimbUp traps baited with several stimuli including CO2. Significantly more ticks were captured and attracted to the NightWatch and CO2-baited ClimbUp traps than the other two trap models. The results suggest that bed bug traps may be useful in brown dog tick monitoring, and CO2 will likely be an important component of a trapping system employed in the future. 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.
Zolnik, Christine P; Makkay, Amanda M; Falco, Richard C; Daniels, Thomas J
Ticks and whole blood were collected from American black bears (Ursus americanus Pallas) between October 2011 and October 2012 across four counties in northwestern New Jersey, an area where blacklegged ticks (Ixodes scapularis Say) and their associated tick-borne pathogens are prevalent. Adult American dog ticks (Dermacentor variabilis Say) were the most frequently collected tick species in late spring, whereas adult and nymphal blacklegged ticks were found in both the late spring and fall months. Additionally, for blacklegged ticks, we determined the quality of bloodmeals that females acquired from black bears compared with bloodmeals from white-tailed deer (Odocoileus virginianus Zimmerman), the most important host for the adult stage of this tick species. Measures of fecundity after feeding on each host species were not significantly different, suggesting that the bloodmeal a female blacklegged tick acquires from a black bear is of similar quality to that obtained from a white-tailed deer. These results establish the American black bear as both a host and quality bloodmeal source to I. scapularis. Thus, black bears may help support blacklegged tick populations in areas where they are both present. In addition, samples of black bear blood were tested for DNA presence of three tick-borne pathogens. Anaplasma phagocytophilum Foggie and Babesia microti Franca were found in 9.2 and 32.3% of blood samples, respectively. All blood samples were quantitative polymerase chain reaction-negative for Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt, & Brenner. Although circulating pathogens were found in blood, the status of black bears as reservoirs for these pathogens remains unknown. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Bursali, Ahmet; Keskin, Adem; Şimşek, Eray; Keskin, Aysun; Tekin, Saban
In order to determine the species composition of infesting ticks, between 2011 and 2012 a total of 1118 wild animals were captured from various regions of Zara, Sivas province, Turkey. A total of 138 ticks were obtained from the 58 host animals. Ticks were identified as Dermacentor marginatus (Sulzer), Haemaphysalis erinacei taurica Pospelova-Shtrom, Haemaphysalis parva (Neumann), Haemaphysalis punctata Canestrini and Fanzago, Haemaphysalis sulcata Canestrini and Fanzago, Hyalomma marginatum Koch, Ixodes laguri Olenev, Ixodes ricinus (L.), Ixodes vespertilionis Koch and Rhipicephalus turanicus Pomerantzev. To the best of our knowledge, there are several new host records for D. marginatus, H. e. taurica and I. laguri. In addition, I. vespertilionis was recorded for the first time in the Central Anatolian Region in Turkey, whereas I. laguri and H. e. taurica are firstly reported in Sivas.
Permethrin is a commonly used acaricide for tick control on domestic animals and in residential environments, while fipronil use is restricted to on-animal treatment. Following widespread reports of permethrin and fipronil application failures to control indoor infestations of Rhipicephalus sanguin...
Garris, G I; Barré, N
Base-line data on acaricide susceptibility of larvae and of larvae and nymphs of the tropical bont tick, Amblyomma variegatum (Fabricius), from Puerto Rico and Guadeloupe were collected on 14 and six compounds, respectively. Nymphs 7-8 weeks old from Puerto Rico and Guadeloupe, and larvae 3-4 weeks old from Guadeloupe, were exposed for 24 or 48 h to residues of acetone dilutions of technical-grade or commercial formulations of acaricides on disposable glass pipettes. Effectiveness of the acaricides in killing nymphs (LC50) from Guadeloupe and Puerto Rico ranged from 0.0001% for deltamethrin2 to 0.269% for malathion. For Puerto Rico, the susceptibility to toxaphene and amitraz, but not to dioxathion, increased with increasing age of nymphs. Nymphs from Guadeloupe were 9.5 times more susceptible to chlorpyrifos than nymphs from Puerto Rico. The susceptibility of larvae from Guadeloupe to acaricides tested ranged from LC50 0.000012% for deltamethrin to 0.0141% for ethion. There was no evidence of development of acaricide resistance in ticks from Guadeloupe or Puerto Rico.
Couret, Janelle; Dyer, M.C.; Mather, T.N.; Han, S.; Tsao, J.I.; LeBrun, R.A.; Ginsberg, Howard
Measuring rates of acquisition of the Lyme disease pathogen, Borrelia burgdorferi sensu lato Johnson, Schmid, Hyde, Steigerwalt & Brenner, by the larval stage of Ixodes scapularis Say is a useful tool for xenodiagnoses of B. burgdorferi in vertebrate hosts. In the nymphal and adult stages of I. scapularis, the duration of attachment to hosts has been shown to predict both body engorgement during blood feeding and the timing of infection with B. burgdorferi. However, these relationships have not been established for the larval stage of I. scapularis. We sought to establish the relationship between body size during engorgement of larval I. scapularis placed on B. burgdorferi-infected, white-footed mice (Peromyscus leucopus Rafinesque) and the presence or absence of infection in larvae sampled from hosts over time. Body size, time, and their interaction were the best predictors of larval infection with B. burgdorferi. We found that infected larvae showed significantly greater engorgement than uninfected larvae as early as 24 h after placement on a host. These findings may suggest that infection with B. burgdorferi affects the larval feeding process. Alternatively, larvae that engorge more rapidly on hosts may acquire infections faster. Knowledge of these relationships can be applied to improve effective xenodiagnosis of B. burgdorferi in white-footed mice. Further, these findings shed light on vector–pathogen–host interactions during an understudied part of the Lyme disease transmission cycle.
Colombo, Valeria C; Antoniazzi, Leandro R; Fasano, Agustín A; Beldomenico, Pablo M; Nava, Santiago
The aim of this communication is to report, for the first time, the occurrence of Amblyomma triste in Santa Fe province, Argentina, and to add a new isolation place for Amblyomma tigrinum. Both species of ticks are vectors of Rickettsia parkeri, a spotted fever group rickettsia. Ticks were recovered from tourists in August 2014 and December 2015 at the Federico Wildermuth Foundation (31° 59'S, 61° 24'O), San Martin Department, Santa Fe province. Five adult ticks were morphologically identified as A. tigrinum (3 females and 1 male) and A. triste (1 female). This is the first finding including both Amblyomma maculatum group species, A. triste and A. tigrinum, together in the same locality in Argentina. This finding suggests that this site might have favorable features for the development of both species of R. parkeri vector. Further studies including sampling of a larger number of ticks and detection of R. parkeri DNA are needed to better document the epidemiology of this rickettsia in Santa Fe.
Dennis, D T; Nekomoto, T S; Victor, J C; Paul, W S; Piesman, J
Lyme disease, caused by infection with Borrelia burgdorferi, is the most frequently reported arthropod-borne disease in the United States. To develop a national map of the distribution of the vectors of B. burgdorferi to humans (Ixodes scapularis Say and Ixodes pacificus Cooley & Kohls ticks), we sent questionnaires to acarologists, health officials, and Lyme disease researchers; surveyed the 1966-1996 MEDLINE data base; and reviewed 1907-1995 National Tick Collection data. Tick collection methods cited included flagging and dragging, deer surveys, small- and medium-sized mammal surveys, CO2 baiting, and receipt of tick submissions. A total of 1,058 unique, county-specific I. scapularis and I. pacificus records was obtained. Tick populations were classified as "reported" (< 6 ticks and 1 life stage identified) or "established" (> or = 6 ticks or > 1 life stage identified). Established populations of I. scapularis were identified in 396 counties in 32 states in the eastern and central United States, whereas established populations of I. pacificus were found in 90 counties in 5 western states. Counties with established populations were most concentrated in the northeastern, upper northcentral, and west-coastal states but were also clustered in southeastern and Gulf-coastal states. A less concentrated distribution was found in the south-central states. Reports were notably missing from all but a few counties in Ohio, West Virginia, western Virginia and North Carolina, Kentucky, and Tennessee. They were absent in the Great Plains and Rocky Mountain regions and from large areas of western states east of the Cascade and Sierra Nevada cordilleras. These data are useful for identifying areas of Lyme disease risk, for targeting Lyme disease prevention strategies, and for monitoring trends in spatial distribution of Lyme disease vector ticks.
Kiffner, Christian; Lödige, Christina; Alings, Matthias; Vor, Torsten; Rühe, Ferdinand
Despite the importance of roe deer as a host for Ixodes ticks in central Europe, estimates of total tick burden on roe deer are not available to date. We aimed at providing (1) estimates of life stage and sex specific (larvae, nymphs, males and females, hereafter referred to as tick life stages) total Ixodes burden and (2) equations which can be used to predict the total life stage burden by counting the life stage on a selected body area. Within a period of 1(1/2) years, we conducted whole body counts of ticks from 80 hunter-killed roe deer originating from a beech dominated forest area in central Germany. Averaged over the entire study period (winter 2007-summer 2009), the mean tick burden per roe deer was 64.5 (SE +/- 10.6). Nymphs were the most numerous tick life stage per roe deer (23.9 +/- 3.2), followed by females (21.4 +/- 3.5), larvae (10.8 +/- 4.2) and males (8.4 +/- 1.5). The individual tick burden was highly aggregated (k = 0.46); levels of aggregation were highest in larvae (k = 0.08), followed by males (k = 0.40), females (k = 0.49) and nymphs (k = 0.71). To predict total life stage specific burdens based on counts on selected body parts, we provide linear equations. For estimating larvae abundance on the entire roe deer, counts can be restricted to the front legs. Tick counts restricted to the head are sufficient to estimate total nymph burden and counts on the neck are appropriate for estimating adult ticks (females and males). In order to estimate the combined tick burden, tick counts on the head can be used for extrapolation. The presented linear models are highly significant and explain 84.1, 77.3, 90.5, 91.3, and 65.3% (adjusted R (2)) of the observed variance, respectively. Thus, these models offer a robust basis for rapid tick abundance assessment. This can be useful for studies aiming at estimating effects of abiotic and biotic factors on tick abundance, modelling tick population dynamics, modelling tick-borne pathogen transmission dynamics or assessing the efficacy of acaricides.
Tuininga, Amy R; Miller, Jessica L; Morath, Shannon U; Daniels, Thomas J; Falco, Richard C; Marchese, Michael; Sahabi, Sadia; Rosa, Dieshia; Stafford, Kirby C
Entomopathogenic fungi are commonly found in forested soils that provide tick habitat, and many species are pathogenic to Ixodes scapularis Say, the blacklegged tick. As a first step to developing effective biocontrol strategies, the objective of this study was to determine the best methods to isolate entomopathogenic fungal species from field-collected samples of soils and ticks from an Eastern deciduous forest where I. scapularis is common. Several methods were assessed: (1) soils, leaf litter, and ticks were plated on two types of media; (2) soils were assayed for entomopathogenic fungi using the Galleria bait method; (3) DNA from internal transcribed spacer (ITS) regions of the nuclear ribosomal repeat was extracted from pure cultures obtained from soils, Galleria, and ticks and was amplified and sequenced; and (4) DNA was extracted directly from ticks, amplified, and sequenced. We conclude that (1) ticks encounter potentially entomopathogenic fungi more often in soil than in leaf litter, (2) many species of potentially entomopathogenic fungi found in the soil can readily be cultured, (3) the Galleria bait method is a sufficiently efficient method for isolation of these fungi from soils, and (4) although DNA extraction from ticks was not possible in this study because of small sample size, DNA extraction from fungi isolated from soils and from ticks was successful and provided clean sequences in 100 and 73% of samples, respectively. A combination of the above methods is clearly necessary for optimal characterization of entomopathogenic fungi associated with ticks in the environment.
Tuininga, Amy R.; Miller, Jessica L.; Morath, Shannon U.; Daniels, Thomas J.; Falco, Richard C.; Marchese, Michael; Sahabi, Sadia; Rosa, Dieshia; Stafford, Kirby C.
Entomopathogenic fungi are commonly found in forested soils that provide tick habitat, and many species are pathogenic to Ixodes scapularis Say, the blacklegged tick. As a first step to developing effective biocontrol strategies, the objective of this study was to determine the best methods to isolate entomopathogenic fungal species from field-collected samples of soils and ticks from an Eastern deciduous forest where I. scapularis is common. Several methods were assessed: (1) soils, leaf litter, and ticks were plated on two types of media; (2) soils were assayed for entomopathogenic fungi using the Galleria bait method; (3) DNA from internal transcribed spacer (ITS) regions of the nuclear ribosomal repeat was extracted from pure cultures obtained from soils, Galleria, and ticks and was amplified and sequenced; and (4) DNA was extracted directly from ticks, amplified, and sequenced. We conclude that (1) ticks encounter potentially entomopathogenic fungi more often in soil than in leaf litter, (2) many species of potentially entomopathogenic fungi found in the soil can readily be cultured, (3) the Galleria bait method is a sufficiently efficient method for isolation of these fungi from soils, and (4) although DNA extraction from ticks was not possible in this study because of small sample size, DNA extraction from fungi isolated from soils and from ticks was successful and provided clean sequences in 100 and 73% of samples, respectively. A combination of the above methods is clearly necessary for optimal characterization of entomopathogenic fungi associated with ticks in the environment. PMID:19496427
Golezardy, H; Horak, I G
During surveys on the tick burdens of various wildlife species in South Africa, nine small antelopes became available for study. Six of these were steenbok, Raphicerus campestris and three sunis, Neotragus moschatus, and their tick burdens are recorded here. The steenbok were examined in three nature reserves and harboured nine tick species. The sunis were examined in a fourth reserve and were infested with eight species. The steenbok and sunis were generally infested with the immature stages of the same tick species that infest larger animals in the same geographic regions. In addition the sunis harboured Haemaphysalis parmata, which in South Africa is present only in the eastern and north-eastern coastal and adjacent areas of KwaZulu-Natal Province. They were also infested with Rhipicephalus kochi, which in South Africa occurs only in the far north-east of the KwaZulu-Natal and Limpopo Provinces.
Loaiza, Jose R; Miller, Matthew J; Bermingham, Eldredge; Sanjur, Oris I; Jansen, Patrick A; Rovira, Jose R; Alvarez, Eric; Rodriguez, Eric; Davis, Philip; Dutari, Larissa C; Pecor, James; Foley, Desmond; Radtke, Meghan; Pongsiri, Montira J
Free-ranging ticks are widely known to be restricted to the ground level of vegetation. Here, we document the capture of the tick species Amblyomma tapirellum in light traps placed in the forest canopy of Barro Colorado Island, central Panama. A total of forty eight adults and three nymphs were removed from carbon dioxide–octenol baited CDC light traps suspended 20 meters above the ground during surveys for forest canopy mosquitoes. To our knowledge, this represents the first report of questing ticks from the canopy of tropical forests. Our finding suggests a novel ecological relationship between A. tapirellum and arboreal mammals, perhaps monkeys that come to the ground to drink or to feed on fallen fruits. PMID:25075277
Russart, Nathan M; Dougherty, Michael W; Vaughan, Jefferson A
Ticks were sampled at nine locations throughout North Dakota during early summer of 2010, using flagging techniques and small mammals trapping. In total, 1,762 ticks were collected from eight of the nine locations. The dominant species were Dermacentor variabilis (Say) (82%), found throughout the state, and Ixodes scapularis Say (17%), found in northeastern counties. A few nymphal and adult I. scapularis tested positive for Borrelia burgdorferi (3%) and Anaplasma phagocytophilum (8%). This is the first report of I. scapularis and associated pathogens occurring in North Dakota and provides evidence for continued westward expansion of this important vector tick species in the United States.
Background Close relationships between ticks and microbial communities are important for tick fitness and pathogen colonization and transmission. Haemaphysalis longicornis, distributed widely in China, can carry and transmit various pathogens and pose serious damages to public health and economics. However, little is known about the broader array of microbial communities and symbionts in H. longicornis under natural conditions. In the present study, we investigated the composition of bacterial communities associated with H. longicornis and evaluated the putative symbionts. Methods The eubacterial 16S rRNA gene clone libraries of H. longicornis were constructed and analyzed by restriction fragment length polymorphism (RFLP) and DNA sequencing. In addition, diagnostic PCR was performed to assess the prevalence, vertical transmission and infection sites of the symbionts in H. longicornis. Results Vertically-transmitted symbionts, potential pathogens and allochthonous nonpathogenic bacteria were identified from the field-collected H. longicornis. Three types of symbionts (Coxiella-like, Arsenophonus-like and Rickettsia-like symbionts) were identified in a single host simultaneously. A series of analyses revealed the vertical transmission, prevalence, and infection sites of these symbionts. However, only Coxiella-like bacteria were transmitted stably in the laboratory-reared ticks. In addition, we identified a novel Coxiella-like agent with 95.31% sequence similarity to the taxon described previously. Conclusions The present study demonstrated that natural H. longicornis harboured a diverse array of microbial communities. Three types of symbionts were identified in a single host simultaneously. Moreover, high prevalence, vertical transmission and the infection sites supported an obligate symbiotic association between Coxiella symbiont and its host. The role of Coxiella symbiont in the host fitness and the interaction among microbial communities remained to be elucidated. Our investigation of microbial communities in the ticks revealed the complexity of ecological interactions between host and microbe and provided insight for the biological control of ticks. PMID:24499619
Martins, Thiago F; Diniz-Reis, Thaís R; Libardi, Gustavo S; Percequillo, Alexandre R; Verdade, Luciano M; Matushima, Eliana R; Labruna, Marcelo B
Between July 2008 and May 2010, we conducted a trophic study on 12 Brazilian wild carnivore species through their faecal analysis in a silvicultural landscape at Angatuba municipality, southern São Paulo state. Predator faeces was identified by morphology, predator hair, and surrounding tracks; prey remnants within faeces were used for morphological identification of the prey. Among the recovered ectoparasites, there were 89 specimens of six tick species in 21 (4.0%) out of 523 analysed samples. Ticks were identified to species level, based on external morphological characters, as following: adults of Amblyomma ovale and Amblyomma sculptum; nymphs of Amblyomma brasiliense, Amblyomma calcaratum, Amblyomma dubitatum, A. ovale, and Ixodes schulzei; and larvae of Amblyomma sp. and Ixodes sp. Generally, the recovered immature ticks were associated with consumed prey (small birds or small mammals), whereas adults were associated with the predator itself, ingested during its self-grooming. Our data show that faeces is an additional information source on ticks in Brazil and which may provide information on ectoparasite-predator-prey interactions.
Sobrino, Raquel; Millán, Javier; Oleaga, Alvaro; Gortázar, Christian; de la Fuente, José; Ruiz-Fons, Francisco
Ticks parasitizing wild carnivores and the tick-borne pathogens (TBPs) that they transmit may affect domestic carnivores and humans. Thus, investigating the role of wild carnivores as tick hosts is of relevance for understanding the life cycle of ticks in natural foci and the epidemiology of TBPs shared with domestic animals and humans. Therefore, the main objective of this study was to determine the ixodid tick fauna of wild carnivores in Peninsular Spain and the environmental factors driving the risk of wild carnivores to be parasitized by ixodid ticks. We hypothesized that the adaptation of tick species to differing climatic conditions may be reflected in a similar parasitization risk of wild carnivores by ticks between bioclimatic regions in our study area. To test this, we surveyed ixodid ticks in wild carnivores in oceanic, continental-Mediterranean, and thermo-Mediterranean bioclimatic regions of Peninsular Spain. We analyzed the influence of environmental factors on the risk of wild carnivores to be parasitized by ticks by performing logistic regression models. Models were separately performed for exophilic and endophilic ticks under the expected differing influence of environmental conditions on their life cycle. We found differences in the composition of the tick community parasitizing wild carnivores from different bioclimatic regions. Modelling results partially confirmed our null hypothesis because bioclimatic region was not a relevant factor influencing the risk of wild carnivores to be parasitized by exophilic ticks. Bioclimatic region was however a factor driving the risk of wild carnivores to be parasitized by endophilic ticks. Spanish wild carnivores are hosts to a relevant number of tick species, some of them being potential vectors of pathogens causing serious animal and human diseases. Information provided herein can be of help to understand tick ecology in Spanish wildlife, the epidemiology of tick-borne diseases, and to prevent the risks of TBPs for wildlife, domestic animals, and humans.
Kollars, T M; Oliver, J H; Kollars, P G; Durden, L A
Based on tick collections recovered from wild vertebrates and by dragging, the seasonal occurrence of adult blacklegged ticks, Ixodes scapularis Say, extended from October through May in southeastern Missouri. Adult activity was bimodal with the higher peak occurring in November followed by a lower peak in February. The activity of immature I. scapularis had the general pattern of that found in the Northeast where Lyme disease is hyperendemic, with larval activity (July) peaking after that of nymphs (May and June). Vertebrates varied in their importance as hosts of I. scapularis. White-tailed deer, Odocoileus virginanus (Zimmerman), and coyotes, Canis latrans Say, were the primary hosts of adult I. scapularis. Broad-headed skinks, Eumeces laticeps (Schneider), and eastern fence lizards, Sceloporus undulatus (Latreille), were the primary hosts of nymphal I. scapularis. The broad-headed skink, 5-lined skink, Eumeces fasciatus (L.), and Carolina wren, Thryothorus ludovicianus (Latham), were the primary hosts of larval I. scapularis. Homeotherms were important hosts of immature I. scapularis, accounting for 30% of nymphs and 39% of larvae collected. The eastern cottontail rabbit, Sylvilagus floridanus (Allen), may play an important role in the epidemiology of Lyme disease in Missouri. Isolates of Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner were made from ticks recovered from rabbits, making the cottontail rabbit a key species for further study of the epidemiology of Lyme borreliosis in Missouri.
Ixodid ticks were collected from 13 sika deer, Cervus n.nippon, shot in the Boso Peninsula in central Japan from late February to early March 1999. Haemaphysalis megaspinosa was the most abundant species of the adults collected, although Haemaphysalis longicornis, H. flava, H. kitaokai, H. cornigera, Ixodes ovatus, and Amblyomma testudinarium were also collected. Males were more abundant than females for H. longicornis, H. megaspinosa, H. flava, and H. kitaokai. Ticks that had inserted their hypostome into its host skin (designated attached) were distinguished from those that were detached and on the host's surface. A greater fraction of males than females of all four species were detached. Females were classified in three feeding stages (engorged, partially engorged, and unfed). More H. longicornis and H. megaspinosa unfed female ticks than engorged and partially-engorged female ticks were collected detached. Our results indicated that H. megaspinosa, H. longicornis, H. flava, and H. kitaokai male ticks detached sooner than female ticks after their host died.
Hornbostel, V L; Ostfeld, Richard S; Benjamin, Michael A
With the incidence of Lyme disease increasing throughout the United States, reducing risk of exposure to the disease is of the utmost concern. In the northeastern U.S., the blacklegged tick, Ixodes scapularis, is the primary vector and the white-footed mouse, (Peromyscus leucopus), the primary reservoir for Borrelia burgdorteri, the bacterium causing Lyme disease. Targeting I. scapularis engorging on white-footed mice with an effective biological control agent, such as the fungus Metarhizium anisopliae, could be an effective and relatively safe control technique. In 2002-2003, we performed laboratory and field experiments to determine whether M anisopliae-treated nesting material could effectively control larval I. scapularis ticks engorging on white-footed mice, and therefore reduce the number of infected nymphal I. scapularis questing the following summer. Our laboratory experiment demonstrated a strong negative effect of M. anisopliae-treated nesting material on survival of I. scapularis larvae feeding on P. leucopus, with 75% versus 35% larval mortality in treatment versus control nests. Our field trials caused only modest, localized reductions in nymphal abundance and had no effect on the proportion of nymphal I. scapularis infected with B. burgdorferi. Field results probably could be improved by increasing the density of nestboxes to allow fungal delivery to a higher proportion of the mouse population and by deploying nestboxes in an area with lower mammalian diversity, such as a suburban landscape.
Duffy, D C; Clark, D D; Campbell, S R; Gurney, S; Perello, R; Simon, N
Nymphal Ixodes scapularis Say, the vector of Lyme borreliosis, was most common in forested areas across Shelter Island, Suffolk County, New York, and least common in xeric habitats such as beach and grassland. At the scale of individual house yards, nymphs were most common at wooded edges of property and least common on lawns. The abundance of ticks at yard edges was positively correlated with numbers on lawns and in landscaping, suggesting that tick abundance in woods affects abundances in adjacent yards. Because 57% of all yard area is adjacent to woodlands on Shelter Island, public health efforts to reduce tick populations in wooded areas should supplement efforts by individual yard owners to decrease risk. Methods of tick control for woodlands should also be evaluated for their effect on tick populations in adjacent yard habitats.
Wang, Xin; Huang, Yong; Niu, Si-bo; Jiang, Bao-Gui; Jia, Na; van der Geest, Leo; Ni, Xue-bing; Sun, Yi; Cao, Wu-Chun
Salp15, a 15-kDa tick salivary gland protein, is both essential for ticks to successfully obtain host blood and also facilitates transmission of Lyme borreliosis. To determine whether the Salp15 gene is expressed in Ixodes persulcatus and Ixodes sinensis, principle vectors of Lyme borreliosis in China, we studied transcriptions of this gene in semi-engorged larvae, nymph and adults of these two species. A total of eight Salp15 homologues, five in I. persulcatus and three in I. sinensis, were identified by reverse transcriptase–polymerase chain reaction (RT-PCR). Interestingly, the intra-species similarity of Salp15 is approximately equal to its interspecies similarity and more than one Salp15 protein is expressed in a certain tick developmental stage. Comparison of DNA and proteins with other available tick Salp15 homologues suggests that the Salp15 superfamily is genetically conserved and diverse in the Ixodes ricinus complex. These findings indicate that Salp15 proteins in the I. ricinus complex may play an essential role in interacting with the host immune system and transmission of Borrelia genospecies. PMID:24714063
Durden, Lance A; Oliver, James H; Banks, Craig W; Vogel, Gregory N
From 1982-1985 and 1993-1999, a total of 309 individual reptiles, mostly lizards and snakes, belonging to 12 species (American alligator, six lizard species, five snake species) was captured on St. Catherine's Island, Liberty County, Georgia, USA, and examined for ticks. Three lizard species, the broad-headed skink Eumeces laticeps, southeastern 5-lined skink Eumeces inexpectatus, and eastern glass lizard Ophisaurus ventralis, were severely infested with larvae and nymphs of the blacklegged tick, Ixodes scapularis. Ticks were not found on any of the other reptile species. Overall, 80% of 65 E. inexpectatus examined were parasitized by a mean intensity of 21.5 larvae and 88% were parasitized by a mean intensity of 4.8 nymphs. Corresponding figures for E. laticeps (n=56) were 93% and 51.3 for larvae and 89% and 7.4 for nymphs, and for O. ventralis (n=3) were 67% and 22.5 for larvae and 100% and 21.3 for nymphs. Larvae and nymphs attached along the lateral grooves of O. ventralis. Nymphs attached mainly behind the ears and in the foreleg axillae whereas larvae mainly attached to these sites and on the hindlegs in Eumeces spp. Seasonally, both larvae and nymphs were recorded on lizards from April through October. A unimodal larval peak was recorded in May or June. Seasonal data for nymphs did not reveal any distinct peaks but small bimodal peaks in mean intensities may have occurred (one in early summer, the other in late summer) suggesting that some ticks complete their life cycle in one year, and others in two years, on St. Catherine's Island. Potential epidemiological consequences of these findings with respect to Lyme disease in the southeastern United States are briefly addressed.
Levine, J F; Apperson, C S; Howard, P; Washburn, M; Braswell, A L
Previously archived museum specimens of lizards collected throughout North Carolina were examined for Ixodes scapularis (Say). Lizards (n = 1,349) collected in 80 of North Carolina's 100 counties were examined. Lizards with ticks were collected in 23 (29%) of the 80 counties from which lizards were examined. I. scapularis was detected on 8.7% (n = 117) of the lizards and was the sole species of tick obtained from lizards. Immature ticks were most frequently found on the southeastern five-lined skink, Eumeces inexpectatus, and the eastern glass lizard, Ophisaurus ventralis. Larvae were most frequently found on the six-lined racerunner, Cnemidophorus sexlineatus. One C. sexlineatus harbored 177 larvae and 2 nymphs. Nymphs were most frequently observed on E. inexpectatus. The majority of counties (chi 2, P < 0.01) where ticks were found on lizards were in the Coastal Plain.
Martins, Thiago F; Onofrio, Valeria C; Barros-Battesti, Darci M; Labruna, Marcelo B
Together with the larval stage, the nymphal stage of ticks of the genus Amblyomma are the most aggressive ticks for humans entering areas inhabited by wildlife and some domestic animals in Brazil. However, due to the absence of morphological descriptions of the nymphal stage of most Brazilian Amblyomma species, plus the lack of an identification key, little or nothing is known about the life history of Amblyomma spp. nymphs in the country. In the present study, morphological description of the nymphal stage, illustrating important external characters through scanning electron microscopy, is provided for nymphs of 15 Amblyomma species that occur in Brazil, for which the nymphal stage had never been described: A. aureolatum, A. auricularium, A. calcaratum, A. coelebs, A. fuscum, A. humerale, A. incisum, A. latepunctatum, A. naponense, A. nodosum, A. ovale, A. pacae, A. pseudoconcolor, A. scalpturatum, A. varium. In addition, the nymphal stage of 12 Amblyomma species, which had been previously described, are redescribed: A. brasiliense, A. cajennense, A. dissimile, A. dubitatum, A. longirostre, A. oblongoguttatum, A. parkeri, A. parvum, A. romitii, A. rotundatum, A. tigrinum, A. triste. The descriptions and redescriptions totalized 27 species. Only 2 species (A. geayi, A. goeldii) out of the 29 Amblyomma species established in Brazil are not included in the present study. A dichotomous identification key is included to support taxonomic identification of the nymphal stage of 27 Amblyomma species established in Brazil.
Labruna, Marcelo B; de Paula, Cátia D; Lima, Thiago F; Sana, Dênis A
From June 2000 to June 2001, a total of 741 ticks were collected from 51 free-living wild animals captured at the Porto-Primavera Hydroelectric power station area, located alongside an approximately 180 km course of the Paran river, between the states of S o Paulo and Mato Grosso do Sul, comprising 9 species of 3 genera: Ambly-omma (7 species), Boophilus (1) and Anocentor (1). A total of 421 immature Amblyomma ticks were reared in laboratory until the adult stage, allowing identification of the species. A. cajennense was the most frequent tick species (mostly immature stages) collected on 9 host species: Myrmecophaga tridactyla, Tamandua tetradactyla,Cerdocyon thous, Puma concolor,Tayassu tajacu, Mazama gouazoubira,Hydrochaeris hydrochaeris,Alouatta caraya, Cebus apella. Other tick species were less common, generally restricted to certain host taxa.
Rivera-Páez, Fredy A; Labruna, Marcelo B; Martins, Thiago F; Sampieri, Bruno Rodrigues; Camargo-Mathias, Maria I
Up to some years ago, the taxon Amblyomma cajennense represented a single tick species in the New World, from southern United States to northern Argentina. Recent studies, based on genetic, reproductive and morphological data reorganized this taxon into a complex of the following 6 valid species: A. cajennense sensu stricto, Amblyomma mixtum, Amblyomma sculptum, Amblyomma interandinum, Amblyomma tonelliae, and Amblyomma patinoi. According to this classification, the A. cajennense complex is currently represented in Colombia by only one species, A. patinoi. Because the Colombian land is surrounded by confirmed records of A. mixtum in Panama and Ecuador, and by A. cajennense s.s. in Venezuela and the Brazilian Amazon, it is possible that these two species could also occur in Colombia. This study aimed to determine the occurrence of ticks of the A. cajennense complex in the Orinoquía region of Colombia. A total of 246 adult ticks of the Amblyomma genus were collected in three sampled regions: 71 females and 110 males in Arauca (Arauca Department), 27 females and 20 males in Nunchía (Casanare Department), and 10 females and 8 males in Yopal (Casanare Department). Based on morphological and molecular analyses, these ticks were identified as A. mixtum. Molecular analyses consisted of DNA sequences of two molecular markers, the nuclear second internal transcribed spacer (ITS2) and the mitochondrial cytochrome c oxidase subunit I gene (COI). The presence of A. mixtum in Colombia is of medical relevance, since this species is incriminated as a vector of Rickettsia rickettsii in Central America.
Soares, Sara Fernandes; Borges, Lígia Miranda Ferreira; de Sousa Braga, Raquel; Ferreira, Lorena Lopes; Louly, Carla Cristina Braz; Tresvenzol, Leonice Manrique Faustino; de Paula, José Realino; Ferri, Pedro Henrique
Repellence responses of Amblyomma cajennense nymphs to callicarpenal, intermedeol, Hyptis suaveolens essential oil, extract of Melia azedarach, Cymbopogon nardus, Spiranthera odoratissima, Chenopodium ambrosioides, Ageratum conyzoides, Mentha pulegium, Ruta graveolens, and Memora nodosa were studied. Among these the extract of C. nardus stood out because of the long-lasting repellence, maintaining, in the highest concentration, 35h of protection against 90% of the nymphs. The essential oil of H. suaveolens and the extracts of C. ambrosioides and A. conyzoides showed good repellence index (66%) when applied in high concentrations. However, greater protection could be obtained at higher concentrations but with a shorter repellence time. Callicarpenal, intermedeol, extract of M. Pulegium, and M. nodosa leaves showed moderate repellence in high concentrations. Extracts from M. azedarach, R. graveolens, S. odoratissima, and M. nodosa roots showed little or no repellent effect. These results show that some plant extracts may represent a promising alternative in the control of infestations by A. cajennense. Copyright 2009 Elsevier B.V. All rights reserved.
Sanches, Gustavo S; Évora, Patrícia M; Mangold, Atílio J; Jittapalapong, Sattaporn; Rodriguez-Mallon, Alina; Guzmán, Pedro E E; Bechara, Gervásio H; Camargo-Mathias, Maria I
In this study, different geographical populations of Rhipicephalus sanguineus sensu lato were compared by molecular, biological, and morphometric methods. Phylogenetic trees were constructed using 12S and 16S rDNA sequences and showed two distinct clades: one composed of ticks from Brazil (Jaboticabal, SP), Cuba (Havana) Thailand (Bangkok) and the so-called "tropical strain" ticks. The second clade was composed of ticks from Spain (Zaragoza), Argentina (Rafaela, Santa Fe) and the so-called "temperate strain" ticks. Morphometric analysis showed good separation between females of the two clades and within the temperate clade. Males also exhibited separation between the two clades, but with some overlap. Multiple biological parameters revealed differences between the two clades, especially the weight of the engorged female. These results confirm the existence of at least two species under the name "R. sanguineus".
Chao, Li-Lian; Shih, Chien-Ming
The genetic identity of Rhipicephalus sanguineus tick was determined for the first time in Taiwan. The phylogenetic relationships were analyzed by comparing the sequences of mitochondrial 16S ribosomal DNA gene obtained from 32 strains of ticks representing six species of Rhipicephalus, two species of Dermacentor and two outgroup species (Haemaphysalis inermis and Ixodes ricinus). Seven major clades can be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. All R. sanguineus ticks of Taiwan were genetically affiliated to the tropical lineage group of R. sanguineus sensu lato with highly homogeneous sequence (99.7-100% similarity), and can be discriminated from the temperate lineage group of Rhipicephalus sp. II and R. turanicus with a sequence divergence ranging from 1.7 to 5.2%. In contrast, the nucleotide variations among other Rhipicephalus spp. and other species/genus of ticks compared with the R. sanguineus ticks of Taiwan were measured from 10.6 to 25.5%. Moreover, intra- and inter-species analysis based on the genetic distance (GD) values indicated a lower level (GD < 0.003) within tropical lineage group compared with temperate lineage group (GD > 0.055) of Rhipicephalus, as well as other (GD > 0.129) and outgroup (GD > 0.236) species. Our results provide the first genetic identification of R. sanguineus ticks collected from Taiwan and demonstrate that all these R. sanguineus of Taiwan affiliated to the tropical lineage group of R. sanguineus sensu lato.
Chao, Li-Lian; Lu, Chun-Wei; Lin, Ying-Fang; Shih, Chien-Ming
Genetic identity and morphological features of a human biting tick, Amblyomma testudinarium, were determined for the first time in Taiwan. Morphological features of adult male and female ticks of Am. testudinarium were observed and photographed by a stereo- microscope. The genetic identity was analyzed by comparing the sequences of mitochondrial 16S ribosomal DNA gene obtained from 18 strains of ticks representing 10 species of Amblyomma, and four outgroup species of Dermacentor and Rhipicephalus ticks. Nine major clades could be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. All these Am. testudinarium ticks collected from Taiwan and Japan were genetically affiliated to a monophyletic group with highly homogeneous sequence (99.8-100% similarity), and can be discriminated from other species of Amblyomma and other genera of ticks (Dermacentor and Rhipicephalus) with a sequence divergence ranging from 6.9 to 23.9%. Moreover, intra- and inter-species analysis based on the genetic distance (GD) values indicated a lower level (GD < 0.003) within the same lineage of Am. testudinarium ticks collected from Taiwan and Japan, as compared with other lineage groups (GD > 0.108) of Amblyomma ticks, as well as outgroup (GD > 0.172) species. Our results provide the first distinguished features of adult Am. testudinarium ticks and the first genetic identification of Am. testudinarium ticks collected from humans in Taiwan. Seasonal prevalence, host range, and vectorial capacity of this tick species in Taiwan need to be further clarified.
of the cell in subtype VIh (Fig. 2). Type IX : In these oval celo, 2 subtypes are distinguished according to cell size and NSG distribution. The NSG...1977) : Neurosecretion in Ornithodoros savignyi (Audouin) (Ixodoidea : Arga- sidae ). The distribution of neurosecretory cells in the brain. J. Vet. Res
In the of period 2003-2007, a total of 382 specimens of reptiles belonging to the following genera were investigated: Testudo, Iguana, Varanus, Gongylophis, Python, Spalerosophis, Psammophis. The material for the present study was a collection of reptiles owned by the "Animals" Ltd from Swietochłowice (Upper Silesia, Poland), specialising in import of exotic animals to Poland, as well as the reptile collections of private breeders. The reptiles that turned out to be the most heavily infected with ticks were the commonly bred terrarium reptiles: Varanus exanthematicus and Python regius and they were imported to Poland from Ghana, Africa. Exotic reptiles are also imported from Southern Europe, Asia and Central America. The presently reported study helped to confirm the fact of transfer of exotic ticks on reptiles to Poland. A total of 2104 tick specimens, representing all stages of development (males, females, nymphs, larvae), were collected. They represented species of the genera Amblyomma and Hyalomma. The following species were found: Amblyomma exornatum Koch, 1844, Amblyomma flavomaculatum (Lucas, 1846), Amblyomma latum Koch, 1844, Amblyomma nuttalli Dönitz, 1909, Amblyomma quadricavum Schulze, 1941, Amblyomma transversale (Lucas, 1844), Amblyomma varanense (Supino, 1897), Amblyomma spp. Koch, 1844, Hyalomma aegyptium (Linnaeus, 1758). All the species of ticks of genus Ambylomma revealed have been discovered in Poland for the first time. The overall prevalence of infection was 77.6%. The highest prevalence value (81.2%) was observed on pythons (Python regius) and (78.7%) on monitor lizards (Varanus exanthematicus). The highest number of ticks was collected from Python regius and Varanus exanthematicus. The mean infection intensity for V. exanthematicus was 7.6 ticks per host, while for P. regius the intensity reached 4.7 ticks. The most abundant tick transferred to Poland on a host was an African tick, Amblyomma latum. Fifty eight specimens of monitor lizards (V. salvator and V. exanthematicus) and 92 specimens pythons (P. regius) were examined, with detailed descriptions of where the parasite was feeding on the body of the host. Among the 434 specimens of ticks collected from the monitor lizards, the majority were attached on the host's legs (40.5%), on the trunk (29.3%), on the head (20.3%), with fewest on the tail (9.9%). Also, 430 specimens of ticks were collected from the bodies of pythons. They mostly parasitized along the whole length of the back (54.4%) and on the stomach side of the trunk (29.8%), less frequently in the area of the cloaca (5.6%), around the eyes (3.7%), in the nostril openings (0.9%) and on the remainder of the head (5.6%). On the hosts, ticks were found at different development stages, but adult development stages dominated. The most frequent were males (999 specimens), then adult females (552 specimens), nymphs (508 specimens) and larvae (45 specimens). During the research, 13 cases of anomalies of morphological structure were confirmed for ticks Amblyomma flavomaculatum, Amblyomma latum and Hyalomma aegyptium. Asymmetries and deformations of the general body shape were observed, as were anomalies concerning structures on the surface of the body and anomalies of the legs. For the first time in Poland, epidemiological tests were carried out in the direction of the infection of exotic ticks gathered from reptiles with micro-organisms which pose a threat for the health of people and animals. For this purpose, molecular techniques - polymerase chain reaction (PCR) and DNA sequencing were used. The isolates from 345 ticks, were examined for the presence of DNA of Anaplasma phagocytophilum, which is the etiological factor in human granulocytic anaplasmosis, and Rickettsia spp. from the spotted fever group, causing human rickettsiosis. This study confirmed the presence of Anaplasma phagocytophilum in two ticks of Amblyomma flavomaculatum (constituting 0.6% of all the ticks investigated) feeding on Varanus exanthematicus. None of the tick specimens, however, contained Rickettsia spp. DNA. The expanding phenomenon of the import of exotic reptiles in Poland and Central Europe is important for parasitological and epidemiological reasons and therefore requires monitoring and wide-ranging prophylactic activities to prevent the inflow of exotic parasites to Poland.
Lane, R S; Burgdorfer, W
In northern California, antibodies to Borrelia burgdorferi were detected in 58 of 73 (79%), and spirochetemias in one of 26 (4%) black-tailed jackrabbits (Lepus californicus californicus), by indirect and direct immunofluorescence, respectively. Five species of ticks (Dermacentor occidentalis, D. parumapertus, Ixodes neotomae, I. pacificus, and Haemaphysalis leporispalustris) were collected from rabbits. Two of these species of ticks were found to contain spirochetes; two of 10 (20%) I. neotomae and two of 174 (1%) H. leporispalustris. A strain of B. burgdorferi was recovered from I. neotomae. One infected H. leporispalustris female passed spirochetes via eggs to about 67% of her progeny. The widespread distribution of the black-tailed jackrabbit, its infestation by at least four ticks (D. occidentalis, D. parumapertus, I. neotomae, and I. pacificus) known to be infected naturally with B. burgdorferi, and the high prevalence of spirochetal antibody in this lagomorph suggest that it might be useful as a sentinel for surveillance of Lyme borreliosis. Spirochetes were detected in 15% of 40 Columbian black-tailed deer (Odocoileus hemionus columbianus) by direct immunofluorescence bound with a Borrelia-specific monoclonal antibody (H9724), but not with a monoclonal antibody (H5332) specific for B. burgdorferi. The geographical overlap of different borreliae in ticks that bite wildlife such as deer may confound spirochetal serosurveys, and underscores the need for more specific serologic tests than those currently available.
Aktas, M; Özübek, S
This study investigated possible transovarial and transstadial transmission of Hepatozoon canis by Rhipicephalus sanguineus (Latreille) ticks collected from naturally infected dogs in a municipal dog shelter and the grounds of the shelter. Four hundred sixty-five engorged nymphs were collected from 16 stray dogs that were found to be infected with H. canis by blood smear and PCR analyses and maintained in an incubator at 28 °C for moulting. Four hundred eighteen nymphs moulted to adults 14-16 d post collection. Unfed ticks from the shelter grounds comprised 1,500 larvae, 2,100 nymphs, and 85 adults; were sorted according to origin, developmental stage, and sex into 117 pools; and screened by 18S rRNA PCR for Hepatozoon infection. Of 60 adult tick pools examined, 51 were infected with H. canis. The overall maximum likelihood estimate (MLE) of infection rate was calculated as 21.0% (CI 15.80-28.21). Hepatozoon canis was detected in 31 out of 33 female pools (MLE 26.96%, CI 17.64-44.33) and 20 out of 27 male pools (MLE 14.82%, CI 20.15-46.41). Among 42 unfed nymph pools collected from the shelter, 26 were infected with H. canis, and MLE of infection was calculated as 1.9% (CI 1.25-2.77). No H. canis DNA was detected in any of the gDNA pools consisting of larva specimens. Partial sequences of the 18S rRNA gene shared 99-100% similarity with the corresponding H. canis isolates. Our results revealed the transstadial transmission of H. canis by R. sanguineus, both from larva to nymph and from nymph to adult, in field conditions. However, there were no evidence of transovarial transmission. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Lord, C C
Activity patterns of nymphal Ixodes scapularis Say were compared between habitat types (dominant tree types: mixed deciduous, oak, white pine, red cedar, sassafras, and spicebush). Both the time of peak abundance and the relative abundance of questing nymphs at the peak were compared. Several smoothing algorithms were tested with the data to determine if they could be used to estimate the time of peak abundance more accurately. Determination of the time of peak abundance using the raw data or simple moving averages was susceptible to outliers. Weighted averages were less susceptible to outliers. The seasonal pattern of nymphal abundance was similar in all habitat types. Variation in the time of peak abundance between habitats was low. Peak densities were lower in deciduous habitats (0.24 +/- 0.05 nymphs per square meter) than in nondeciduous habitats (0.85 +/- 0.15 nymphs per square meter); this could have resulted from higher host use of the nondeciduous areas. These data suggest that there are differences in the population dynamics of nymphs found in different habitats.
de Souza Chagas, Ana Carolina; de Barros, Luiz Daniel; Cotinguiba, Fernando; Furlan, Maysa; Giglioti, Rodrigo; de Sena Oliveira, Márcia Cristina; Bizzo, Humberto Ribeiro
Herbal drugs have been widely evaluated as an alternative method of parasite control, aiming to slow development of resistance and obtain low-cost biodegradable parasiticides. This study evaluated the in vitro efficacy on Rhipicephalus (Boophilus) microplus of extracts from Carapa guianensis seed oil, Cymbopogon martinii and Cymbopogon schoenanthus leaf essential oil, and Piper tuberculatum leaf crude extract and similar synthesized substances. In the immersion test, engorged females were evaluated in five dilutions ranging from 10% to 0.030625% concentration. In the larval test on impregnated filter paper, the concentration ranged from 10% to 0.02%. The treatments and controls were done in three replicates. Chemical analysis of the oils was performed by gas chromatography. The main compounds were oleic acid (46.8%) for C. guianensis and geraniol for C. martinii (81.4%), and C. schoenanthus (62.5%). The isolated and synthesized substances showed no significant effect on larvae and adult. C. martinii and P. tuberculatum showed the best efficacy on the engorged females. The LC(50) and LC(90) were 2.93% and 6.66% and 3.76% and 25.03%, respectively. In the larval test, the LC(50) and LC(90) obtained for C. martinii, P. tuberculatum, and C. schoenanthus were 0.47% and 0.63%, 0.41% and 0.79%, 0.57% and 0.96%, respectively. The fact that geraniol is present in greater quantities in C. martinii explains its higher activity in relation to C. shoenanthus. It is necessary to validate the in vivo use of safe and effective phytoparasiticidal substances. Efforts should be focused on developing formulations that enhance the efficacy in vivo and lengthen the residual period.
Loaiza, Jose R; Miller, Matthew J; Bermingham, Eldredge; Sanjur, Oris I; Jansen, Patrick A; Rovira, Jose R; Alvarez, Eric; Rodriguez, Eric; Davis, Philip; Dutari, Larissa C; Pecor, James; Foley, Desmond; Radtke, Meghan; Pongsiri, Montira J
Free-ranging ticks are widely known to be restricted to the ground level of vegetation. Here, we document the capture of the tick species Amblyomma tapirellum in light traps placed in the forest canopy of Barro Colorado Island, central Panama. A total of forty eight adults and three nymphs were removed from carbon dioxide-octenol baited CDC light traps suspended 20 meters above the ground during surveys for forest canopy mosquitoes. To our knowledge, this represents the first report of questing ticks from the canopy of tropical forests. Our finding suggests a novel ecological relationship between A. tapirellum and arboreal mammals, perhaps monkeys that come to the ground to drink or to feed on fallen fruits.
Lado, Paula; Nava, Santiago; Labruna, Marcelo B; Szabo, Matias P J; Durden, Lance A; Bermudez, Sergio; Montagna, Matteo; Sánchez Quirós, Ana C; Beati, Lorenza
The geographical distribution of Amblyomma parvum Aragão 1908 in the New World is disjunct, with two main clusters separated from each other by the Amazon basin. The main objectives of this study were to further investigate the systematic relationships within A. parvum, to determine whether or not populations from different geographical areas might represent cryptic species, and to reconstruct the phylogeographical evolutionary history of the species. The genetic diversity of A. parvum collected throughout its distributional range was analyzed by using 6 molecular markers: 5 mitochondrial [the small and the large ribosomal subunits 12rDNA and 16SrDNA, the cytochrome oxidase I (COI) and II (COII) and the control region or d-loop (DL)], and one nuclear (ITS2, Inter transcribed spacer 2). Phylogenetic trees were inferred by using maximum parsimony and Bayesian analyses. In addition, node dating was attempted for the main lineages identified phylogenetically. Although mitochondrial and nuclear topologies were not totally congruent, they all identified at least two main supported clusters, a Central American lineage, and a Brazilian-Argentinian lineage. Clade support and divergence values strongly suggest that the two lineages correspond to different taxonomic entities. Node dating placed the split between the Central American and the Brazilian-Argentinian lineages at approximately 5.8-4.9 Mya, just after the progressive replacement of the dry areas that occupied the northern part of South America by the Amazon Basin in the early-mid Miocene. This event might be the cause of fragmentation and putative speciation within the ancestral relatively xerophilic A. parvum population.
Bezerra Santos, Marcos Antônio; de Macedo, Lucia Oliveira; de Souza, Islanne Barbosa; do Nascimento Ramos, Carlos Alberto; Alves, Leucio Câmara; Ramos, Rafael Antonio Nascimento; de Carvalho, Gílcia Aparecida
The biological control of ticks represents an alternative method to the chemical control, given its ecological-friendly approach. Amongst the alternatives, the use of parasitoids of the genus Ixodiphagus (Hymenoptera: Encyrtidae) has been largely investigated. The aim of this study was to document and molecularly characterize Ixodiphagus wasps in ticks from a tropical region of Brazil. From October 2015 to March 2016, Rhipicephalus sanguineus sensu lato ticks (n=1814) were collected from naturally infested dogs and Ixodiphagus larvae were detected by microscopic examination. In addition, adult wasps were obtained in the laboratory. Larvae and adults were molecularly identified as Ixodiphagus hookeri. These findings suggest that this type of parasitism deserves to be studied in local tick populations, in order to elucidate the role of these wasps as a potential alternative to chemical tick control.
Düttmann, Christiane; Flores, Byron; Kadoch Z, Nathaniel; Bermúdez C, Sergio
We document the species of ticks that parasitize livestock in Nicaragua. The study was based on tick collection on cattle and horses from 437 farms in nine departments. Of 4841 animals examined (4481 cows and 360 horses), 3299 were parasitized, which represent 68 % of the bovines and 67 % of the equines in study: 59 cows and 25 horses were parasitized by more than one species. In addition, 280 specimens of the entomological museum in León were examined. The ticks found on cattle were Rhipicephalus microplus (75.2 % of the ticks collected), Amblyomma mixtum (20.8 %), A. parvum (2.6 %), A. tenellum (0.7 %), A. maculatum (0.7 %). While the ticks collected from the horses were: Dermacentor nitens (41.5 %), A. mixtum (31.7 %), R. microplus (13.8 %), A. parvum (6.5 %), A. tenellum (3.3 %), D. dissimilis (2.4 %) and A. maculatum (0.8 %).
Models predicting current habitat availability for four prominent tick species in Africa (Boophilus decoloratus, Amblyomma hebraeum, Rhipicephalus appendiculatus and Hyalomma truncatum) were constructed using remotely sensed information about abiotic variables and a point-to-point similarity metric. Year-to-year variations in the forecasted habitat suitability over the period 1983-2000 show a clear decrease in habitat availability, which is attributed primarily to increasing temperature in the region over this period. Climate variables were projected to the year 2015 using Fourier series analysis of the decadal abiotic data. The simulations show a trend toward the destruction of the habitats of the four tick species. In addition, a sensitivity analysis was developed to probe the changes in the habitat suitability in response to variations in temperature, vegetation availability and water vapour deficit. Four basic scenarios were studied: increasing or decreasing the temperature 1 or 2 degrees C together with correlated variations in the other abiotic variables. A decrease in temperature was predicted to promote habitat gain for every species except H. truncatum, while an increase of 1 degrees C was forecast to sustain a small but positive response in A. hebraeum and B. decoloratus. Increasing the temperature by 2 degrees C was forecast to have damaging effects on the habitat structure of all four species. The effect of climate warming on the habitat range of these ticks is considered in the light of economically sound control measures over an ecological background.
Ioffe-Uspensky, I; Mumcuoglu, K Y; Uspensky, I; Galun, R
Life cycle parameters of 2 closely related tick species, Rhipicephalus sanguineus Latreille and R. turanicus Pomerantsev, were studied under laboratory conditions. Both Rhipicephalus, which have small adults, demonstrated the same adaptations as large tick species inhabiting deserts and semideserts: high reproductive rate, decrease in egg size, and an increase in interstage growth to compensate for the smaller size at birth. Pronounced quantitative differences between both species were discerned in relation to these adaptations. Female R. turanicus produced twice as many eggs as R. sanguineus which was facilitated by the greater amount of blood engorged by females and by the smaller egg weight in R. turanicus as compared with R. sanguineus. In all developmental stages, the weight increase from unfed to fed ticks was greater in R. turanicus than in R. sanguineus (23% higher in larvae, 118% in nymphs, and 26% in females). The increase in weight in R. turanicus from the unfed larva (0.013 mg) to the unfed female (3.31 mg) was 254-fold, and in R. sanguineus it was 127-fold (from 0.021 to 2.54 mg). In nymphal R. turanicus, the higher density and the greater height of the dorsal epicuticular folds, as well as procuticular indentations found inside the folds allow this tick to stretch its alloscutum during blood engorgement to a greater extent than R. sanguineus. The rates of blood ingestion (for nymphs and females), egg maturation, and metamorphosis were 1.1-1.7 times greater in R. turanicus than in R. sanguineus. A life cycle strategy with both a higher reproductive rate and faster development in R turanicus may be explained by its greater dependence on environmental factors than that in R. sanguineus.
Movila, A; Deriabina, T; Morozov, A; Sitnicova, N; Toderas, I; Uspenskaia, I; Alekhnovici, A
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.
Beati, Lorenza; Nava, Santiago; Burkman, Erica J; Barros-Battesti, Darci M; Labruna, Marcelo B; Guglielmone, Alberto A; Cáceres, Abraham G; Guzmán-Cornejo, Carmen M; León, Renato; Durden, Lance A; Faccini, João L H
Amblyomma cajennense F. is one of the best known and studied ticks in the New World because of its very wide distribution, its economical importance as pest of domestic ungulates, and its association with a variety of animal and human pathogens. Recent observations, however, have challenged the taxonomic status of this tick and indicated that intraspecific cryptic speciation might be occurring. In the present study, we investigate the evolutionary and demographic history of this tick and examine its genetic structure based on the analyses of three mitochondrial (12SrDNA, d-loop, and COII) and one nuclear (ITS2) genes. Because A. cajennense is characterized by a typical trans-Amazonian distribution, lineage divergence dating is also performed to establish whether genetic diversity can be linked to dated vicariant events which shaped the topology of the Neotropics. Total evidence analyses of the concatenated mtDNA and nuclear + mtDNA datasets resulted in well-resolved and fully congruent reconstructions of the relationships within A. cajennense. The phylogenetic analyses consistently found A. cajennense to be monophyletic and to be separated into six genetic units defined by mutually exclusive haplotype compositions and habitat associations. Also, genetic divergence values showed that these lineages are as distinct from each other as recognized separate species of the same genus. The six clades are deeply split and node dating indicates that they started diverging in the middle-late Miocene. Behavioral differences and the results of laboratory cross-breeding experiments had already indicated that A. cajennense might be a complex of distinct taxonomic units. The combined and congruent mitochondrial and nuclear genetic evidence from this study reveals that A. cajennense is an assembly of six distinct species which have evolved separately from each other since at least 13.2 million years ago (Mya) in the earliest and 3.3 Mya in the latest lineages. The temporal and spatial diversification modes of the six lineages overlap the phylogeographical history of other organisms with similar extant trans-Amazonian distributions and are consistent with the present prevailing hypothesis that Neotropical diversity often finds its origins in the Miocene, after the Andean uplift changed the topology and consequently the climate and ecology of the Neotropics.
Battsetseg, Badgar; Boldbaatar, Damdinsuren; Battur, Banzragch; Xuan, Xuenan; Fujisaki, Kozo
A complementary DNA coding a novel kynurenine aminotransferase (KAT) molecule from Haemaphysalis longicornis tick embryo was cloned and characterized. The transcription of the HlKAT occurs at all stages during tick development as well as in the midgut, salivary glands, ovary, and synganglion of adult ticks, and protein expression levels increased during the blood-feeding course. The HlKAT gene without signal peptide was successfully expressed as a glutathione S-transferase fusion protein in soluble form, which is capable of catalyzing the transamination of kynurenine and 3-hydroxykynurenine to kynurenic acid and xanthurenic acid, respectively. The purified recombinant HlKAT showed dose-dependent inhibition effect on the growth of equine babesial parasite, Babesia caballi, in in vitro culture. All results suggested that a specific HlKAT is present in tick and HlKAT may play an important physiological role in H. longicornis. This is the first report of a member enzyme of tryptophan pathway in Chelicerata.
Colombo, Valeria C; Nava, Santiago; Antoniazzi, Leandro R; Monje, Lucas D; Racca, Andrea L; Guglielmone, Alberto A; Beldomenico, Pablo M
The present study explores associations of different factors (i.e. host parameters, presence of other ectoparasites and [mainly biotic] environmental factors) with burdens of Ixodes loricatus immature stages in one of its main hosts in Argentina, the rodent Akodon azarae. For 2 years, rodents were trapped and sampled monthly at 16 points located in four different sites in the Parana River Delta region. Data were analysed with generalized linear mixed models with a negative binomial response (counts of larvae or nymphs). The independent variables assessed were (a) environmental: trapping year, presence of cattle, type of vegetation, rodent abundance; (b) host parameters: body length, sex, body condition, blood cell counts, natural antibody titers and (c) co-infestation with other ectoparasites. Two-way interaction terms deemed a priori as relevant were also included in the analysis. Most of the associations investigated were found significant, but in general, the direction and magnitude of the associations were context-dependent. An exception was the presence of cattle, which was consistently negatively associated with both larvae and nymphs independently of all other variables considered and had the strongest effect on tick burdens. Mites, fleas and Amblyomma triste were also significantly associated (mostly positively) with larval and nymph burdens, and in many cases, they influenced associations with environmental or host factors. Our findings strongly support that raising cattle may have a substantial impact on the dynamics of I. loricatus and that interactions within the ectoparasite community may be an important-but generally ignored-driver of tick dynamics.
Ribeiro, Carla Carolina Dias Uzedo; Baêta, Bruna de Azevedo; Valim, Jaqueline Rodrigues de Almeida; Teixeira, Rafaella Câmara; Cepeda, Patrícia Barizon; da Silva, Jenevaldo Barbosa; da Fonseca, Adivaldo Henrique
The establishment of laboratory colonies of ticks is often hampered by their lack of adaptation to alternative hosts. The aim of this study was to artificially feed partially engorged Dermacentor (Anocentor) nitens females through plastic tips, and to identify what are the optimal conditions of application of this technique to get as much as possible close to the natural conditions. The technique of artificial feeding through plastic tips allowed the engorgement of D. nitens ticks to a final weight within the normal range for the species. Copyright © 2014 Elsevier GmbH. All rights reserved.
Grassman, L I; Sarataphan, N; Tewes, M E; Silvy, N J; Nakanakrat, T
Ixodid ticks were collected and identified from 8 wild carnivore species in Phu Khieo Wildlife Sanctuary, northeastern Thailand. Six tick species belonging to 4 genera were recovered and identified from 132 individuals. These included Amblyomma testudinarium (n = 36), Haemaphysalis asiatica (n = 58), H. hystricis (n = 31), H. semermis (n = 3), Rhipicephalus haemaphysaloides (n = 3), and Ixodes granulatus (n = 1). Leopard cats (Prionailurus bengalensis) (n = 19) were infested with 4 tick species, whereas yellow-throated marten (Martes flavigula) (n = 4), clouded leopard (Neofelis nebulosa) (n = 2), and dhole (Cuon alpinus) (n = 1) were infested with 3 tick species, Asiatic golden cat (Catopuma temmincki) (n = 2) with 2 species, and marbled cat (Pardofelis marmorata), binturong (Arctictis binturong), and large Indian civet (Viverra zibetha) each infested with 1 species. This information contributes to the knowledge available on the ectoparasites of wild carnivores in Southeast Asia.
Muñoz-Leal, Sebastián; González-Acuña, Daniel
The seabird tick Ixodes uriae White 1852, has the most extensive geographical distribution of all tick species, including Afrotropical, Australasian, Nearctic, Neotropical and Palearctic Zoogeographic Regions. Additionally, this tick species parasitizes a wide range of seabirds and constitutes a host for several viral and bacterial agents. Considering the current biological knowledge about this tick species, in this article we list localities, hosts, tick-borne microorganisms and viruses transmitted by I. uriae described in the literature and include new geographical records. Copyright © 2015 Elsevier GmbH. All rights reserved.
Gharbi, Mohamed; Darghouth, Mohamed Aziz
Hyalomma scupense (syn. Hyalomma detritum) is a two-host domestic endophilic tick of cattle and secondarily other ungulates in the Maghreb region (Africa). This species transmits several pathogens, among which two are major livestock diseases: Theileria annulata and Theileria equi. Various other pathogens are also transmitted by this tick species, such as Anaplasma phagocytophilum and Ehrlichia bovis. Hyalomma scupense is common in sub-humid and semi-arid areas of several regions in the world, mainly in the Maghreb region. In this region, adults attach to animals during the summer season; larvae and nymphs attach to their hosts during autumn, but there is a regional difference in H. scupense phenology. There is an overlap between immature and adult ticks, leading in some contexts to a dramatic modification of the epidemiology of tick-borne diseases. This tick species attaches preferentially to the posterior udder quarters and thighs. Tick burdens can reach 130 ticks per animal, with a mean of 60 ticks. Calves are 70 times less infested than adult cattle. The control can be implemented through six options: (i) rehabilitation of the farm buildings by roughcasting and smoothing the outer and inner surfaces of the enclosures and walls. This control option should be recommended to be combined with a thorough cleaning of the farm and its surrounding area. With regard to Theileria annulata infection, this control option is the most beneficial. (ii) Acaricide application to animals during the summer season, targeting adults. (iii) Acaricide application during the autumn period for the control of the immature stages. (iv) Acaricide application to the walls: many field veterinarians have suggested this option but it is only partially efficient since nymphs enter deep into the cracks and crevices. It should be used if there is a very high tick burden or if there is a high risk of tick-borne diseases. (v) Manual tick removal: this method is not efficient since the ticks can feed on several other animal species in the farm. This control option can lead to a reduction of the tick population, but not a decrease in tick-borne disease incidence. (vi) Vaccination: this control option consists of injecting the protein Hd86; trials have shown a partial effect on nymphs, with no effect on adult ticks. Combination of two of these control options is recommended in regions where there are high burdens of important tick vectors. Further studies are needed to improve our knowledge on this tick species in the Maghreb region, since the number of published studies on Hyalomma scupense in this region is very limited. © M. Gharbi et al., published by EDP Sciences, 2014.
Monteiro, Caio Márcio Oliveira; Araújo, Laryssa Xavier; Gomes, Geovany Amorim; Senra, Tatiane Oliveira Souza; Calmon, Fernanda; Daemon, Erik; de Carvalho, Mario Geraldo; Bittencourt, Vânia Rita Elias Pinheiro; Furlong, John; Prata, Márcia Cristina de Azevedo
In vitro effect of the association of the entomopathogenic nematodes Heterorhabditis bacteriophora HP88 and Heterorhabditis indica LPP1 with the essential oil of Lippia sidoides on engorged females of Rhipicephalus microplus was assessed. Engorged females with homogeneous weights (p >0.05) were divided into six groups of ten ticks each (each female = an experimental unit). In the treated groups, the ticks were exposed to the oil (40 μl/ml=4%) and nematodes (300 entomopathogenic nematodes (EPNs/tick) separately and also to the nematodes together with the oil, while in the control group, the females were immersed in Tween 80 (3%). All the treatments caused a significant reduction in the egg mass weight (p <0.05). The hatching percentage of larvae was reduced (p <0.05) in the groups treated with H. bacteriophora HP88, H. indica LPP1, and H. bacteriophora HP88 associated with the oil, but in the group treated only with the oil, the hatching of percentage of larvae rate was similar to that of the control group (p >0.05). The percentage of control in the group exposed only to the oil was 50.7%, while in the other treated groups, the percentage of control was greater than 95 %, reaching 100 %in the group treated with H. indica LPP1 associated with the oil. The results of the L. sidoides essential oil in the concentrations tested in association with both H. bacteriophora HP88 and H. indica LPP1 indicate that these combinations can be used to control R. microplus.
Monteiro, Caio Márcio de Oliveira; Matos, Renata da Silva; Araújo, Laryssa Xavier; Campos, Roberson; Bittencourt, Vânia Rita Elias Pinheiro; Dolinski, Claudia; Furlong, John; Prata, Márcia Cristina de Azevedo
This study evaluated the efficacy of four entomopathogenic nematode (EPN) strains in insect cadaver formulations against Rhipicephalus microplus and compared the efficacy of the most virulent EPNs applied in cadavers of Galleria mellonella and Tenebrio molitor. In the first experiment, infected G. mellonela larvae were used as the source of EPNs. Engorged females of R. microplus were placed in pots filled with soil and different numbers of G. mellonella larvae infected with one of four species of nematodes. All treatments with EPNs of the genus Heterorhabditis caused significant reduction (p<0.05) in the egg mass weight and hatching percentage of larvae. The EPNs of the genus Steinernema, except for the group exposed to Steinernema carpocapsae ALL, whose source nematodes included six larvae of G. mellonella, caused a significant reduction (p<0.05) in the egg mass weight produced per female. Steinernema feltiae SN applied with two, four, and six cadavers and S. carpocapsae ALL with two cadavers caused a reduction in hatching percentage of larvae of R. microplus (p<0.05). The percentage of control was above 95% in all groups treated with Heterorhabditis bacteriophora HP88 and Heterorhabditis indica LPP1 and in the treatment with four larvae infected with S. feltiae SN. The second experiment followed the same methodology, using G. mellonella and T. molitor larvae infected by the two most virulent EPNs. H. bacteriophora HP88 and H. indica LPP1 in different formulations caused reduction in the egg mass weight and hatching percentage of larvae. The percentage of control were 82.4 and 84.9% for H. bacteriophora HP88 and H. indica LPP1, respectively, formulated in T. molitor, and reaching 99.9% in groups formulated with G. mellonella. The EPNs tested in insect cadaver formulation showed pathogenicity to engorged females of R. microplus and EPNs of the genus Heterorhabditis formulated in G. mellonella larvae were more effective. Copyright © 2014 Elsevier B.V. All rights reserved.
Botelho, J R; Linardi, P M; da Encarnação, C D
We received for examination a small colection of ticks captured in the National Park of the Serra da Canastra (MG), between 1979 and 1980. The authors demonstrated the existence of a broad co-accomodation of Amblyomma pseudoconcolor on Edentata of the family Dasypodidae, being Dasypodini the tribe more adjusted to this infestation. In conformity to the Figs 1 and 2, Dasypodini are probably the real hosts of A. pseudoconcolor and also the oldest hosts. For the first time, A. pseudoconcolor is also recorded on Cabassous tatouay, C. unicinctus, Priodontes maximus and Euphractus sexcincuts. Also for the first time A. pseudoconcolor and Amblyomma calcaratum were recorded in the State of Minas Gerais. The ectoparasites are deposited in the "Departamento de Parasitologia da Universidade Federal de Minas Gerais, Brasil".
Zhioua, E.; Browning, M.; Johnson, P.W.; Ginsberg, H.S.; LeBrun, R.A.
The entomopathogenic fungus Metarhizium anisopliae is highly pathogenic to the black-legged tick, Ixodes scapularis. Spore concentrations of 108/ml for engorged larvae and 107/ml for engorged females resulted in 100% tick mortality, 2 wk post-infection. The LC50 value for engorged larvae (concentration to kill 50% of ticks) was 107 spores/ml. Metarhizium anisopliae shows considerable potential as a microbial control agent for the management of Ixodes scapularis.
Suleiman, Elham A; Shigidi, M T; Hassan, S M
In the Sudan, ticks and Tick-borne Diseases (TBDs) with subsequent costs of control and treatment are causing substantial economic loss. Control of ticks is mainly by chemical insecticides. The rising environmental hazards and problem of resistance has motivated research on biological agents as alternative methods of control. The present study aims at controlling livestock ticks using fungi for their unique mode of action besides their ability to adhere to the cuticle, to germinate and penetrate enzymatically. The study was conducted to evaluate the fungus Metarhizium anisopliae for tick control as an alternative mean to chemical acaricides. Pathogenicity of the fungus was tested on different developmental stages of the tick Hyalomma anatolicum. The fungus induced high mortality to flat immature stages. It, also, affected reproductive potential of the females. Egg laid, hatching percent, fertility and moulting percent of immature stages were significantly (p < or = 0.05) reduced. It was, also, shown that the fungus had ability to adhere to the cuticle and penetrate the integument of the tick. Conidia of the fungus were isolated from their internal tissues. This phenomenon is important in considering fungi as bioinsecticides. Infection of eggs laid by treated engorged female ticks, with the fungus might demonstrate suggesting transovarian transmission. The use of M. anisopliae to control ticks is discussed.
Rodriguez-Vivas, R I; Ojeda-Chi, M M; Trinidad-Martinez, I; Pérez de León, A A
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 intensive use of synthetic acaricides for tick control exerts a strong selective pressure for brown dog ticks to become resistant to them. Here, we investigated claims from the field regarding treatment failure associated with the use of veterinary products containing ivermectin (IVM) to control brown dog ticks infesting dogs in Yucatan state, Mexico. Dogs in six state municipalities were inspected to sample 15 R. sanguineus s.l. Interviews were conducted with dog owners to gather information on the history of dog treatment with conventional acaricides and IVM. The larval immersion test was used on the progeny of adult female ticks infesting dogs to test for susceptibility to IVM. Dose-mortality regressions, lethal concentrations (LC), their confidence intervals, and slope were estimated by probit analysis. Ten tick populations (66.7%) were classified as resistant compared with the most susceptible population. A high inter-population variation in the phenotypic level of IVM resistance was evident (resistance ratio at LC50% and LC99% ranged from 1.0 to 30.5, and from 1.0 to 458.8, respectively). Tick populations classified as resistant were collected from dogs known to have been treated with IVM. To our knowledge, this is the first report of IVM resistance in R. sanguineus s.l. worldwide. Veterinary and pet owner education on integrated tick management practices is required to avoid widespread resistance and increased treatment failure with products containing IVM and other macrocyclic lactones used to control endo- and ectoparasites affecting dogs. Integrated tick management will also help mitigate the burden of brown dog tick-borne diseases on human and animal populations. Copyright © 2016 Elsevier B.V. All rights reserved.
Aguirre, D H; Gaido, A B; Cafrune, M M; Castelli, M E; Mangold, A J; Guglielmone, A A
The efficacy of a commercial pour-on formulation of eprinomectin, a macrocyclic lactone, against experimental infestations of Boophilus microplus (Canestrini) ticks was evaluated in two trials involving 27 Bos taurus calves. The first trial was designed to evaluate the effects of a single treatment at a dose of 0.5 mg/kg of body weight against standard size B. microplus females (4.5-8.0 mm long). A significant reduction in tick numbers (P<0.05, Wilcoxon test) was observed between treated calves as compared to untreated ones from Day 3 (44% efficacy) after treatment to the end of the trial on Day 28 (96.9%), with a peak efficacy of 97.1% on Day 21. In the second trial the effect of eprinomectin on standard size tick numbers, engorgement weight and fertility of female ticks from calves with a single treatment dose of 1 mg/kg on Day 0 and calves treated twice at a dose of 0.5 mg/kg on Days 0 and 4 was evaluated. An efficacy >93% was obtained from Day 2 to Day 28 after treatment in calves treated twice at 0.5 mg/kg, and to the end of the trial (Day 35) in calves treated once with 1 mg/kg. The 1mg/kg treatment provided >98% residual efficacy for at least 7 days. During the first part of the second trial the efficacy of eprinomectin resulted from a dramatic adverse effect on engorgement weight and fertility of female ticks, with 100% control on Day 5 (dosage of 1 mg/kg) and on Days 6 and 7 (two doses of 0.5 mg/kg). Following Day 7, most of the effect was due to reduction in the number of standard size female ticks.
Tembo, S D; Kiwanuka, A
Significant increases in serum globulins (alpha 1, alpha 2, beta and gamma) were observed in mountain leopard tortoises (Geochelone pardalis) after they had been immunized with nymphal homogenates of Amblyomma marmoreum. There was a concomitant significant increase in the numbers of leukocytes (lymphocytes, basophils, monocytes and eosinophils). Resistance to nymphal-challenge infestations was manifested by reduced feeding time, lower engorgement masses, and significantly fewer (P < 0.0001) numbers of nymphs that moulted. These findings are contrary to the generally reported phenomenon, that ticks do not induce resistance in their natural hosts.
Rechav, Y; Fielden, L J
A survey of Amblyomma marmoreum Koch ticks recorded from the leopard tortoise, Geochelone paradalis Bell, in the National Zoological Gardens, Pretoria, South Africa, was carried out over a 19-mo period. No significant differences were found between the tick burdens on male and female tortoises. A. marmoreum showed a clear seasonal pattern of abundance. Larvae were present on the tortoise host during late summer, with a peak in February and March; nymphs were abundant during winter, with a peak in June and July. Male ticks were found throughout the year, but females were present only during spring and early to midsummer with a peak in October. It was demonstrated that each developmental stage of A. marmoreum showed only one peak of activity per year.
Resistance to ivermectin (IVM) in field populations of Rhipicephalus microplus of Brazil has been observed since 2001. In this work, four selection methods (infestations with: (1) IVM-treated larvae; (2) larvae from IVM-treated adult female ticks; (3) larvae from IVM-treated adult female ticks on an...
Araújo, Laryssa Xavier; Novato, Tatiane Pinheiro Lopes; Zeringota, Viviane; Matos, Renata Silva; Senra, Tatiane Oliveira Souza; Maturano, Ralph; Prata, Márcia Cristina Azevedo; Daemon, Erik; Monteiro, Caio Márcio Oliveira
This is the first study to investigate the activity of thymol on Rhipicephalus microplus larvae under semi-natural conditions. For this purpose, tests were conducted in pots with Brachiaria decumbens seedlings containing cattle tick larvae. Thymol, diluted in ethanol 50° GL, was tested at concentrations of 2.5, 5.0, 10.0, 15.0, and 20.0 mg/mL, along with the control group treated with the solvent alone. Each treatment was composed of five pots (1 pot = a repetition). The experiment was performed in three steps. On the first day, the larvae were applied at the base of the signalgrass. Twenty-four hours later, approximately 25 mL of the solution was applied with thymol on the top of the vegetation in each pot. The survival of the larvae was measured 24 h after application of the solutions. Each pot was analyzed individually, and the grass fillets contained larvae were cut with scissors, placed in Petri dishes, and taken to the laboratory to count the number of living larvae. At the highest concentrations (10, 15, and 20 mg /mL), the number of live larvae declined by more than 95 % in relation to the control group. The lethal concentration 50 % (LC50) and LC90 values were 3.45 and 9.25 mg/ml, respectively. The application of thymol in semi-natural conditions starting concentration of 10 mg/mL significantly reduced the number of living R. microplus larvae.
Mendes, Andressa da Silva; Daemon, Erik; Monteiro, Caio Márcio de Oliveira; Maturano, Ralph; Brito, Fernanda Calmon; Massoni, Tainara
The aim of the present study was to evaluate the acaricidal efficacy of thymol on unengorged and engorged larvae and engorged nymphs of Amblyomma cajennense. To perform the test for unengorged larvae, the larval packet technique was employed and mortality was evaluated 24h after the test, while for engorged larvae and engorged nymphs the immersion technique was employed and mortality was evaluated after 15 days. In all the experiments, the following concentrations of thymol were tested: 2.5, 5.0, 10.0, 15.0 and 20.0mg the thymol/ml. The control group was exposed to water and 1% DMSO and there were 10 repetitions for each treatment. The values found for mortality of unengorged larvae were 18.2%, 51.8%, 97.6%, 93.5% and 94.5%, and for engorged nymphs the values were 26.0%, 92.2%, 100.0%, 100.0%, 100.0%, in concentrations of 2.5, 5.0, 10.0, 15.0 and 20.0mg of thymol/ml, respectively. In the test with engorged larvae, mortality was 100.0% in all treatments. Based on the results, it is possible to conclude that thymol has acaricidal activity against immature stages of A. cajennense.
Muyobela, Jackson; Nkunika, Philip Obed Yobe; Mwase, Enala Tembo
The objective of the study was to determine the acaricidal properties of Bobgunnia madagascariensis (Desv.) J.H. Kirkbr. and Wiersema (Leguminosae) against adult Amblyomma variegatum (Fabricius) ticks, using Tephrosia vogelii Hook.f. (Leguminosae) as a positive control. Plant extracts of both were prepared using methanol, acetone and chloroform as extraction solvents. Methanol leaf extracts of T. vogelii (0.014 g) and methanol fruit extracts of B. madagascariensis (0.0062 g) gave the highest mean extraction weights among the plant parts and solvents used. In free contact bioassays, only methanol extracts of the bark and leaf material of T. vogelii and methanol fruit extracts of B. madagascariensis produced 100 % mortality of A. variegatum ticks in 24 h. The acaricidal activity of methanol leaf extracts of T. vogelii persisted for up to 8 days while that of fruit extracts of B. madagascariensis persisted for only 6 days. In topical application bioassays, the toxicity of T. vogelii and B. madagascariensis extracts was found to be significantly different at 95 % confidence level, with B. madagascariensis extracts (LD50 0.030 w/v) being more toxic than T. vogelii extracts (LD50 0.555 w/v). This study has shown that plant extracts of B. madagascariensis and T. vogelii extracts have significant in vitro acaricidal activity against A. variegatum ticks and can thus be considered as alternatives for tick control. Further research is however required on persistence, safety and the required application rates.
Carroll, M.C.; Ginsberg, H.S.; Hyland, K.E.
The distribution of nymphal Ixodes dammini Spielman, Clifford, Piesman & Corwin in residential lawns was assessed by flagging on Prudence Island, RI. The number of ticks per sample was five times greater in lawns adjacent to woods than in lawns adjacent to other lawns. Relative tick abundance was negatively correlated with distance from the woods, but the decline was gradual. Spirochete prevalence in ticks did not differ among lawn types or at different distances from the woods. Therefore, barriers that keep people away from the wood edge probably lower the risk of acquiring Lyme disease, but there is still a risk. Even with physical barriers at lawn-wood edges, personal precautions to prevent tick bites should be followed.
Onofrio, Valeria C; Ramirez, Diego G; Giovanni, Dalton N S; Marcili, Arlei; Mangold, Atilio J; Venzal, José M; Mendonça, Ronaldo Z; Labruna, Marcelo B; Barros-Battesti, Darci M
The species Ixodes aragaoi Fonseca was described as Ixodes ricinus aragaoi, and later placed in synonymy with Ixodes affinis. However, this synonymy was rejected and the subspecies was elevated to species, and named as I. aragaoi. Some researchers did not consider the validity of I. aragaoi and maintained the synonymy proposed until 1998 when I. aragaoi was revalidated, and it was suggested that Ixodes pararicinus could be a synonym. The aim of this study was to confirm the taxonomic validity of I. aragaoi by means of redescription of adults and molecular analysis. Morphological studies were performed by optical and scanning electron microscopy; types of I. aragaoi were compared with those of I. pararicinus from Argentina, and also with material of I. pararicinus from Uruguay and I. affinis from the United States. Mitochondrial 16S rDNA sequences were obtained for determining phylogenetic relationships based on maximum parsimony. Morphological and molecular differences between I. aragaoi, I. pararicinus from Argentina, and I. affinis confirm the validity of the first each of these species. The morphological similarities of I. pararicinus from Uruguay with I. aragaoi, and the small distance of nucleotide sequences between them, confirm that the Uruguayan ticks are in fact I. aragaoi and expand the geographical distribution of this species. Based on the specimens of Ixodes examined in the present study, from the same locality of the types of I. ricinus rochensis in Uruguay, we agree with the synonymy of this subspecies with I. aragaoi as previously reported. Finally, our analyses indicate that both I. aragaoi and Ixodes fuscipes, another South American tick species, belong to the I. ricinus complex, currently composed of 19 species.
Amblyomma mixtum is a tick species in the Amblyomma cajennense complex. The known geographic range of A. mixtum extends from Texas in the USA to western Ecuador and some islands in the Caribbean. Amblyomma mixtum is a vector of disease agents of veterinary and public health importance. The objective...
Ginsberg, Howard S.; Zhioua, Elyes; Mitra, Shaibal; Fischer, Jason L.; Buckley, P.A.; Verret, Frank; Underwood, H. Brian; Buckley, Francine G.
Spatial distribution patterns of black-legged ticks, Ixodes scapularis, in deciduous and coniferous woodlands were studied by sampling ticks in different woodland types and at sites from which deer had been excluded and by quantifying movement patterns of tick host animals (mammals and birds) at the Lighthouse Tract, Fire Island, NY, from 1994 to 2000. Densities of nymphal ticks were greater in deciduous than coniferous woods in 3 of 7 yr. Only engorged ticks survived the winter, and overwintering survival of engorged larvae in experimental enclosures did not differ between deciduous and coniferous woods. Nymphs were not always most abundant in the same forest type as they had been as larvae, and the habitat shift between life stages differed in direction in different years. Therefore, forest type by itself did not account for tick distribution patterns. Nymphal densities were lower where deer had been excluded compared with areas with deer present for 3 yr after exclusion, suggesting that movement patterns of vertebrate hosts influenced tick distribution, but nymphal densities increased dramatically in one of the enclosures in the fourth year. Therefore, movements of ticks on animal hosts apparently contribute substantially to tick spatial distribution among woodland types, but the factor(s) that determine spatial distribution of nymphal I. scapularis shift from year to year.
Monteiro, Caio Márcio Oliveira; Araújo, Laryssa Xavier; Matos, Renata Silva; da Silva Golo, Patrícia; Angelo, Isabele Costa; de Souza Perinotto, Wendell Marcelo; Coelho Rodrigues, Camila Aparecida; Furlong, John; Bittencourt, Vânia Rita Elias Pinheiro; Prata, Márcia Cristina Azevedo
The aim of the study was to assess the effect of the association of entomopathogenic nematodes and fungi on Rhipicephalus microplus. The nematodes used were Heterorhabditis bacteriophora HP88 and Heterorhabditis indica LPP1 and the fungi were Metarhizium anisopliae IBCB 116 and Beauveria bassiana ESALQ 986. In the groups treated with the fungi, the females were immersed for 3 min in a conidial suspension, while in the groups treated with the nematodes, the ticks were exposed to infective juveniles. To evaluate the interaction between entomopathogens, the females were first immersed in a conidial suspension and then exposed to the nematodes. The egg mass weight and hatching percentage values of the groups treated with M. anisopliae IBCB 116 and B. bassiana ESALQ 986 in the two experiments were statistically similar (p > 0.05) to the values of the control group. In the groups treated only with nematodes, there was a significant reduction (p < 0.05) in the egg mass weight, a fact also observed for the hatching percentage of the group treated with H. indica LPP1. In all the groups treated with nematodes in association with fungi, there was a significant reduction (p < 0.05) in the egg mass weight and hatching percentage. The percentage of control of the groups treated with fungi alone varied from 31 to 55%. In the groups treated with nematodes associated or not with fungi, the control percentage was always greater than 90% and reached 100% in the group treated with H. bacteriophora HP88 associated with the fungus M. anisopliae IBCB 116.
Sobreira Rodrigues, Daniel; Avila de Carvalho, Henrique; Almeida Fernandes, André; Freitas, Carolina Maria Viana; Cerqueira Leite, Romário; de Oliveira, Paulo Roberto
The ixodid Amblyomma aureolatum is suspected to play a role in the epidemiology of wild life-cycle hemoparasites, which frequently infect dogs in rural and hunting areas in Brazil. Little is known about its bionomics. The objective of the present study was to evaluate some bionomic aspects of A. aureolatum ticks in Brazil. One engorged female, collected from a dog (Canis familiaris) in São Sebastião das Aguas Claras, State of Minas Gerais, was used to establish a colony in the laboratory. Subsequently its parasitic stage progeny were fed on domestic dogs and laboratory animals. The free-living stages were incubated at 27 degrees C +/- 2 degrees C and minimum 70% relative humidity in a BOD incubator. The egg incubation period ranged from 31 to 34 days; the parasitic period of larvae ranged from 4 to 6 days and ecdysis to nymphs occurred from day 19 up to day 22. The parasitic period of nymphs ranged from 5 to 8 days and the period of ecdysis to adults from 31 to 33 days. The parasitic period of adults ranged from 11 to 15 days, the pre-oviposition period from 6 to 12 days, and the oviposition period from 9 to 38 days. The total duration of the life cycle ranged from 116 to 168 days.
Kariuki, Edward K; Penzhorn, Barend L; Horak, Ivan G
Several ixodid tick species are shared between domestic cattle and African buffaloes (Syncerus caffer). So too, are a number of tick-borne diseases. The aim of the study was to compare the species composition of ticks that infest cattle and buffaloes utilising the same habitat within the Tsavo Conservation Area, Kenya. To this end, 25 cattle and 62 buffaloes were each opportunistically sampled for ticks on a single occasion in February 2010. Eight species, namely Amblyomma gemma, Amblyomma lepidum, Hyalomma albiparmatum, Hyalomma rufipes, Hyalomma truncatum, Rhipicephalus evertsi evertsi, Rhipicephalus pravus and Rhipicephalus pulchellus infested both cattle and buffaloes. Three species, Rhipicephalus (Boophilus) sp., Rhipicephalus kochi, and Rhipicephalus muehlensi were collected only from cattle, and three species, Hyalomma impeltatum, Rhipicephalus humeralis and Rhipicephalus praetextatus were present only on buffaloes. The attachment sites of the various tick species were also recorded. New locality records for H. impeltatum and H. truncatum and the first confirmed locality record for Rhipicephalus praetextatus sensu stricto in Kenya were documented.
Wanzala, W; Okanga, S
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.
Mastropaolo, Mariano; Nava, Santiago; Guglielmone, Alberto A; Mangold, Atilio J
The fertility of hybrids from two distinct populations of Amblyomma cajennense from different ecological regions of Northern Argentina was analyzed. Two colonies of A. cajennense from El Rey National Park (RNP), Salta Province (24º41'S, 64º36'W), and Copo National Park (CNP), Santiago del Estero Province (25º55'S, 61º43'W) were established infesting rabbits with adults collected from vegetation. Reproductive parameters of the first generation in laboratory of each colony and their crosses were evaluated considering engorged weight of females, engorged period of females, pre-oviposition period of females, minimum egg incubation period, reproductive efficiency index [REI = number of eggs laid/weight of the females in mg], and fertility efficiency index [FEI = number of hatched larvae/weight of the females in mg]. Infestations were made as follows: Group 1) RNP males and females; Group 2) CNP males and females; Group 3) males from CNP and females from RNP; Group 4) males from RNP and females from CNP. The engorgement weight of the females from CNP that mated with males from RNP was significantly lighter than those of the engorged females obtained in the other 3 crosses, and the engorged period of the females from CNP that mated with males from RNP was significantly longer that the engorged period of the females belonging to the remaining groups. The females from group 3 and 4 had a FEI extremely low in comparison with the FEI obtained from the engorged females originated from the groups 1 and 2. Biological implication of these findings is discussed.
Onofrio, Valeria Castilho; Barros-Battesti, Darci Moraes; Marques, Sandro; Faccini, João Luiz Horácio; Labruna, Marcelo Bahia; Beati, Lorenza; Guglielmone, Alberto Alejandro
Amblyomma varium Koch, 1844 is a Neotropical tick, known as the 'sloth's giant tick', with records from southern Central America to Argentina. It is found almost exclusively on mammals of the families Bradypodidae and Magalonychidae (Xenarthra). Differences exist in discussions with regard to the dentition of the female hypostome being either 3/3 or 4/4. The male was also originally described as having a short spur on coxa IV, but some specimens recently collected from different Brazilian localities have this spur three times longer. These differences beg the question of whether there is more than one species included under this taxon. In order to answer this question and to clarify the taxonomic characters of this species, 258 adult specimens were examined, and a redescription of male and female based on light and scanning electron microscopy is provided. In addition, DNA was extracted from males with either a long or a short spur on coxa IV to help settle this question for future investigations on their taxonomy. The morphological study showed that the dental formula pattern for males and females is 3/3 and 4/4, respectively. When sequenced, the 12 S rDNA genes of both A. varium males with long and short spurs on coxa IV were found to be identical, indicating that the length of the spurs on coxa IV is likely to be an intraspecifically polymorphic character of this species.
Norval, R A; Sutherst, R W; Kerr, J D
Infestations of adults and nymphs of Amblyomma hebraeum were counted on Brahman (Br), Brahman x Simmental (BS), Sanga (Sa) and Hereford (He) steers exposed to infested pastures at Mbizi in southern Zimbabwe in 1986-1987. Herefords were always the most heavily infested, while the Sanga tended to carry the fewest ticks with the Brahman and Brahman x Simmental groups being in between. The ratios of the engorged females on the four breeds were 2.3:1.4:1.4:1.0 for He:Br:BS:Sa. The ratios of the standard nymphs were 2.2:1.4:1.7:1.0 for He:Br:BS:Sa. The results confirm earlier observations in Africa and support the view that there are genetic differences between breeds in the expression of resistance to this tick species.
Labruna, Marcelo B; Soares, João F; Martins, Thiago F; Soares, Herbert S; Cabrera, Ricardo R
The present study evaluated the reproductive compatibility of the crosses between adult ticks of the following three geographically different populations of Amblyomma cajennense: State of São Paulo (SP), southeastern Brazil; State of Rondônia (RO), northern Brazil; and Colombia (CO). In addition, crosses between A. cajennense ticks from Argentina (AR) and SP ticks were also performed. The Argentinean population (AR) was compatible with SP because their crosses resulted in high % egg hatching (mean values ranging from 71.5 to 93.5%), similarly to all homologous (intrapopulational) crosses. In contrast, the tick populations SP, RO, and CO were shown to be incompatible with each other, since their heterologous (interpopulational) crosses always resulted in very low % egg hatching (range: 0-5%). The F(1) larval offspring derived from some of these females that yielded 5% egg hatching were reared until the F(1) adult stage. In all cases, only adult females molted from engorged nymphs. These F(1) females were likely to be a product of thelytokous parthenogenesis of the SP, RO, and CO females that were used in the heterologous crosses. Reproductive incompatibility is not expected to occur between different populations of a single species. Thus, our results suggest that the taxon A. cajennense might be represented by a complex of different species, whereas SP and AR ticks might represent a single species. Further populational genetic studies, coupled with extensive morphological analyses, are needed to clarify and determine a possible complex of valid species that might have been classified under the taxon A. cajennense.
Labruna, Marcelo B; Terrassini, Flávio A; Camargo, Luís Marcelo A
An adult male of the tick Amblyomma rotundatum Koch was collected on a naturally infested lizard, Tropidurus sp. (Squamata: Tropiduridae), at Monte Negro, State of Rondonia, Brazil. The tick's identity was confirmed morphologically and by analysis of the second internal transcribed spacer of the ribosomal DNA. This is the third known male specimen of A. rotundatum, a species that has been shown to reproduce exclusively by parthenogenesis. The two previously reported male specimens seemed to be partially teratological or gynandromorphic, whereas the present specimen shows no visible genetic or developmental anomaly.
Estrada-Peña, A; Guglielmone, A A; Mangold, A J; Castellá, J
Gas chromatography has been used to analyze the variation in cuticular hydrocarbon patterns between several populations of Amblyomma cajennense. 88 compounds were detected and these could be divided into 17 groups of hydrocarbons. Heterozygosis in the populations ranges from 0% to 25.84%. Isomers for pentacosane, heptacosane and nonatriacontane are the most variable, with 13, 10 and 11 variants, respectively. Nei's genetic identity and genetic distance show that populations may be considered as regional variants of only one species: the results do not indicate the presence of sibling species. However, a relatively high genetic distance has been observed between several Cuban and continental populations, suggesting a long reproductive isolation. Gas chromatography of cuticular hydrocarbons is a good alternative to isozyme analysis for population studies, when collecting conditions do not allow the use of live ticks and only alcohol-preserved collections are available. The high number of compounds available for genetic studies will provide excellent markers for evaluating the extent of gene flow and migration of tick species.
Beati, Lorenza; Patel, Jaymin; Lucas-Williams, Helene; Adakal, Hassane; Kanduma, Esther G; Tembo-Mwase, Enala; Krecek, Rosina; Mertins, James W; Alfred, Jeffery T; Kelly, Susyn; Kelly, Patrick
The genetic diversity of Amblyomma variegatum (Fabricius) from four Caribbean islands and five African countries was compared by analyzing the sequences of three gene fragments, two mitochondrial (12SrDNA and D-Loop-DL), and one nuclear (intergenic transcribed spacer 2 [ITS2]). Genetic variability of the ITS2 DNA fragment consisted of only uninformative single nucleotide mutations, and therefore this gene was excluded from further analyses. Mitochondrial gene divergences among African populations and between Caribbean and African populations were very low. Nevertheless, the data suggest that A. variegatum is divided into distinct East and West African groups, the western group including all Caribbean samples. Phylogenetic analyses of the 12SrDNA and DL gene sequences showed that the West African A. variegatum clustered in a well-supported monophyletic clade, distinct from eastern paraphyletic lineages. Sequences of A. variegatum from the Caribbean were embedded in the West African clade, which supports the known West African historical origin for these ticks.
Zúquete, Sara Tudela; Coelho, João; Rosa, Fernanda; Vaz, Yolanda; Cassamá, Bernardo; Padre, Ludovina; Santos, Dulce; Basto, Afonso P; Leitão, Alexandre
Tick infestations are a major problem for animal production in tropical areas where prevention and control remain deficient. The present study sought to assess the awareness of traditional cattle producers towards the importance of ticks and aimed at the identification of tick species infesting bovines within the Geba River basin, Guinea-Bissau. Interviews with producers revealed that the majority directly correlates the presence of ticks with the occurrence of diseases in cattle. However, insufficient or inadequate control approaches prevail. A total of 337 ticks were collected on bovines at 18 different villages (10 during dry season, and 8 during rainy season). The tick species collected during the dry season were Rhipicephalus (Boophilus) geigyi (56.5%), followed by Amblyomma variegatum (23.3%), Rhipicephalus (Boophilus) annulatus (17.6%) and Hyalomma truncatum (1%). In the rainy season A. variegatum was the most collected (88.9%), followed by R. (Boophilus) geigyi (4.2%), R. (Boophilus) annulatus (3.4%), Rhipicephalus sanguineus group (2.8%) and H. truncatum (0.7%). To support species identification, segments of both cytochrome c oxidase I (COI) and 12S ribosomal RNA (12S) genes were sequenced and the data gathered were analysed by maximum likelihood and parsimony. Morphological and genetic data of individual specimens gathered in this study provide relevant information for future studies on tick population dynamics in the region. In addition, it led to a deeper characterization of R. sulcatus and a R. sanguineus-like specimen, exploring their genetic relationship with other R. sanguineus, which supports their classification as distinct species within R. sanguineus group.
Lubelczyk, Charles; Lacombe, Eleanor H; Elias, Susan P; Beati, Lorenza; Rand, Peter W; Smith, Robert P
Ticks collected from mustelids from four counties in Maine and one in New Hampshire were identified after harvest. Of the 18 fishers Martes pennanti Erxleben, two mink Neovison vison Schreber, and one long-tailed weasel Mustela frenata Lichtenstein, 589 ticks were collected and identified. They were identified as, in order of abundance, Ixodes gregsoni Lindquist, Wu, and Redner (158 larvae, 189 nymphs, four adults), Ixodes cookei Packard (99 larvae, 77 nymphs, six adults), Ixodes scapularis Say (53 adults), Dermacentor variabilis Say (two nymphs), and Ixodes angustus Neumann (one nymph). Seasonally, all but the D. variabilis were collected in winter. This study reports the first record of adult I. scapularis from a M. pennanti in the northeastern United States. Copyright © 2014 Elsevier GmbH. All rights reserved.
McPherson, M; Shostak, A W; Samuel, W M
Larvae of winter ticks, Dermacentor albipictus (Packard), ascend vegetation in autumn and form clumps that attach to passing ungulate hosts. We tested the hypothesis that vegetation height determines the height of clumps. During the vegetation-to-ungulate transmission period (early September to mid-November), larvae were released at the base of simulated vegetation (nylon rods 245 cm tall) in outdoor and laboratory trials and in the absence of host cues. Rod height exceeded the height of the tallest ungulate host, which is the moose, Alces alces (L.). Most larvae stopped climbing and formed clumps 50-190 cm above ground, which coincided with torso heights of moose; elk, Cervus elaphus L.; and deer, Odocoileus spp. Rafinesque. More clumps formed in outdoor trials than in laboratory trials and clump heights tended to increase over the course of the experiment, but clump number, size, and height did not correlate with weather conditions. Winter tick larvae appear to determine their height above ground in the absence of external cues, but this mechanism may be modified by external conditions.
Lysyk, T J; Dergousoff, S J
Cattle and sheep can develop immunity to paralysis caused by Dermacentor andersoni Stiles; however, this has been reported only in animals that were initially challenged with a high dose of ticks and exhibited clear symptoms of paralysis. Paralysis in sheep occurs in a dose-dependent fashion, with no paralysis occurring in sheep exposed to <0.2 ticks per kilogram sheep weight, and 100% paralysis in sheep exposed to >0.8 ticks per kilogram. This experiment was conducted to determine if sheep exposed to a low dose of ticks would also develop immunity to paralysis. Sheep were exposed to either a low (0.2 ticks per kilogram) or high dose of ticks (0.8 ticks per kilogram), then re-exposed to a second challenge of a paralyzing dose of ticks. All naïve sheep (eight of the eight) were paralyzed, while paralysis occurred in only four of the eight sheep previously exposed to a low dose, and one of the eight sheep previously exposed to a high dose. Results indicate that immunity can develop when sheep are exposed to a subclinical dose of paralyzing ticks, but in a smaller percentage of animals than those exposed to a high dose of ticks. Vaccine development perhaps remains the best option for nonacaricidal control of tick paralysis. © Her Majesty the Queen in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
3 10. type ("c" cells) is only distributed in the 6. NOWs K.S. 41965) Anatomy of the central subpenineuraal layer of H. dromedari and also in D...7COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and iderify by bloc number) FTEC GROUP SUB-GRC: Ticks; Ayaiomia dromedari
Johnson, T L; Bjork, J K H; Neitzel, D F; Dorr, F M; Schiffman, E K; Eisen, R J
Ixodes scapularis Say, the black-legged tick, is the primary vector in the eastern United States of several pathogens causing human diseases including Lyme disease, anaplasmosis, and babesiosis. Over the past two decades, I. scapularis-borne diseases have increased in incidence as well as geographic distribution. Lyme disease exists in two major foci in the United States, one encompassing northeastern states and the other in the Upper Midwest. Minnesota represents a state with an appreciable increase in counties reporting I. scapularis-borne illnesses, suggesting geographic expansion of vector populations in recent years. Recent tick distribution records support this assumption. Here, we used those records to create a fine resolution, subcounty-level distribution model for I. scapularis using variable response curves in addition to tests of variable importance. The model identified 19% of Minnesota as potentially suitable for establishment of the tick and indicated with high accuracy (AUC = 0.863) that the distribution is driven by land cover type, summer precipitation, maximum summer temperatures, and annual temperature variation. We provide updated records of established populations near the northwestern species range limit and present a model that increases our understanding of the potential distribution of I. scapularis in Minnesota.
Wilson, M L; Dykstra, E A; Schmidt, B A
The survival of unfed adult Hyalomma truncatum Koch held under different regimes of constant temperature (5, 17, 24, and 30 degrees C) and relative humidity (10, 50, and 80%) was monitored during > 1 yr. Longevity of this medically important African tick was shortest at the highest temperature and lowest relative humidity (100% dead at week 25). Conversely, H. truncatum lived longest at lower temperatures and higher relative humidity (< 100% dead at week 64). The combined effects of temperature and humidity, measured as vapor pressure deficit, were strongly related to survival of these ticks. The survival of males and females was similar and was independent of the weight of ticks. These findings have implications for the maintenance and study of laboratory colonies of H. truncatum and for the development of tick control strategies to reduce vectorial capacity.
Prusinski, M. A.; Mertins, J. W.; Meehan, L. J.
Gynandromorphism, the simultaneous occurrence of both male and female genotypic and morphological characteristics in a single individual of a normally sexually dimorphic species, is rare in ticks. The phenomenon is documented previously for free-living specimens representing several tick genera, particularly Amblyomma and Hyalomma, but only rarely in Ixodes. Here we describe the first two known gynandromorphs of the blacklegged tick, Ixodes scapularis Say, collected while flagging vegetation during routine tick surveillance in the Hudson Valley region of New York State. Uniquely, both specimens display some morphological features typical of nymphs, in addition to those of both males and females. PMID:26336313
Domingues, Luciana Ferreira; Giglioti, Rodrigo; Feitosa, Karina Alves; Fantatto, Rafaela Regina; Rabelo, Márcio Dias; Oliveira, Márcia Cristina de Sena; Oliveira, Gilson Pereira de; Bechara, Gervasio Henrique; Chagas, Ana Carolina de Souza
Measures to control the cattle tick, Rhipicephalus (Boophilus) microplus, based only on chemical products are becoming unsustainable, mainly because of the development of resistance. The objective of this study was to test the effect of the aqueous extract of pineapple skin (AEPS) and bromelain extracted from the stem (Sigma-Aldrich®, B4882) on engorged females and larvae of R. (B.) microplus in vitro. These substances were diluted in water and evaluated at eight concentrations. Engorged females were collected and distributed in groups of 10, with three repetitions for each treatment. After immersion in the solutions, the females were placed in an incubator for observation of survival, oviposition and larval hatching. The larval packet method was used, also with three repetitions with about 100 larvae each. The packets were incubated and the readings were performed after 24 h. The estimated reproduction and efficacy of the solutions were calculated. The LC(50) and LC(90) were estimated using the Probit procedure of the SAS program. The eight concentrations were compared within each treatment by the Tukey test. For the experiment with engorged females, the most effective concentrations were 125, 250 and 500 mg/mL: 33%, 48% and 59% for the AEPS and 27%, 51% and 55% for the bromelain. The LC(50) and LC(90) values were, respectively, 276 and 8691 mg/mL for AEPS and 373 and 5172 mg/mL for bromelain. None of the dilutions tested was effective against the larvae of R. (B.) microplus. This is the first report of the action of pineapple extracts or their constituents on cattle ticks. The results demonstrate that further studies regarding composition of tick cuticle, with evaluation of other solvents and formulations, should be conducted seeking to enhance the effect of pineapple extracts and compounds against this ectoparasite. Copyright © 2013 Elsevier Inc. All rights reserved.
Piña, Francisco Tobias Barradas; da Silva Rodrigues, Vinicius; de Oliveira Souza Higa, Leandro; Garcia, Marcos Valério; Barros, Jacqueline Cavalcante; de León, Adalberto Angel Pérez; Andreotti, Renato
Amblyomma mixtum is a tick species in the Amblyomma cajennense complex. The known geographic range of A. mixtum extends from Texas in the USA to western Ecuador and some islands in the Caribbean. Amblyomma mixtum is a vector of disease agents of veterinary and public health importance. The objective of this study was to describe the life cycle of A. mixtum under laboratory conditions. Bovines, rabbits and sheep were infested with larvae, nymphs, and adult ticks under controlled conditions to assess several biological parameters. Eggs, larvae, nymphs and adults were kept in an incubator (27 °C temperature and 80% relative humidity) when they were off the host. The average life cycle of A. mixtum was 88 and 79 days when fed on rabbits and cattle, respectively. Sheep were found to be unsuitable because no ticks attached. The rabbit is a more practical host to maintain a colony of A. mixtum under laboratory conditions. The data from this study can be considered as an example for the life cycle of A. mixtum. However, caution must be exercised when making comparisons to the biology of A. mixtum in its natural habitat.
Soualah-Alila, Hana; Bouslama, Zihad; Amr, Zuhair; Bani Hani, Rihan
Parasitism of Ixodes ricinus on three species of lizards (Psammodromus algirus, Podarcis vaucheri and Timon pater) in northeastern Algeria was studied. Psammodromus algirus was the most preferred host, T. pater was least preferred. Nymphs of I. ricinus were found attached to lizards from March to August in various numbers. Most nymphs were collected during March, April and June for P. algirus, and most larvae from April until August. Larval stages were found to be mostly associated with P. vaucheri during the study period, with the highest number of recovered larvae in June.
Gharbi, Mohamed; Aziz Darghouth, Mohamed
Hyalomma scupense (syn. Hyalomma detritum) is a two-host domestic endophilic tick of cattle and secondarily other ungulates in the Maghreb region (Africa). This species transmits several pathogens, among which two are major livestock diseases: Theileria annulata and Theileria equi. Various other pathogens are also transmitted by this tick species, such as Anaplasma phagocytophilum and Ehrlichia bovis. Hyalomma scupense is common in sub-humid and semi-arid areas of several regions in the world, mainly in the Maghreb region. In this region, adults attach to animals during the summer season; larvae and nymphs attach to their hosts during autumn, but there is a regional difference in H. scupense phenology. There is an overlap between immature and adult ticks, leading in some contexts to a dramatic modification of the epidemiology of tick-borne diseases. This tick species attaches preferentially to the posterior udder quarters and thighs. Tick burdens can reach 130 ticks per animal, with a mean of 60 ticks. Calves are 70 times less infested than adult cattle. The control can be implemented through six options: (i) rehabilitation of the farm buildings by roughcasting and smoothing the outer and inner surfaces of the enclosures and walls. This control option should be recommended to be combined with a thorough cleaning of the farm and its surrounding area. With regard to Theileria annulata infection, this control option is the most beneficial. (ii) Acaricide application to animals during the summer season, targeting adults. (iii) Acaricide application during the autumn period for the control of the immature stages. (iv) Acaricide application to the walls: many field veterinarians have suggested this option but it is only partially efficient since nymphs enter deep into the cracks and crevices. It should be used if there is a very high tick burden or if there is a high risk of tick-borne diseases. (v) Manual tick removal: this method is not efficient since the ticks can feed on several other animal species in the farm. This control option can lead to a reduction of the tick population, but not a decrease in tick-borne disease incidence. (vi) Vaccination: this control option consists of injecting the protein Hd86; trials have shown a partial effect on nymphs, with no effect on adult ticks. Combination of two of these control options is recommended in regions where there are high burdens of important tick vectors. Further studies are needed to improve our knowledge on this tick species in the Maghreb region, since the number of published studies on Hyalomma scupense in this region is very limited. PMID:24507485
Campos, Eldo; Moraes, Jorge; Façanha, Arnoldo R; Moreira, Erica; Valle, Denise; Abreu, Leonardo; Manso, Pedro P A; Nascimento, Aline; Pelajo-Machado, Marcelo; Lenzi, Henrique; Masuda, Aoi; Vaz, Itabajara da Silva; Logullo, Carlos
The present work evaluates the kinetics of utilization of the main potential energy sources throughout the embryonic developmental stages of Boophilus microplus. The embryonic development of this arthropod is completed in 21 days. Cellularization of the blastoderm occurs on the 6th day and is rapidly followed by germ band extension and segmentation, whose first signs are visible on the 7th day. Cellularization is typically a maternal-driven process, carried out by molecular determinants deposited in the oocyte during oogenesis. On the other hand, segmentation is of zygotic nature, being the consequence of the synthesis of various components by the growing embryo. The enhancement in total B. microplus RNA was observed after cellularization, corroborating the replacement of maternal-driven processes by embryonic zygotic expression. An abrupt increase in oxygen consumption was observed from cellularization until the 8th day of development. The reduction in dry weight at the same period and the susceptibility of oxygen consumption to KCN suggest that the respiration process is activated during early embryonic development. A marked decrease in total lipid content occurred between the 5th and 7th days of development, suggesting this is the main energy source for cellularization. A major reduction in carbohydrate content occurred later, between the 7th and 9th days, and it could be assigned to the morphological segmentation of the embryo. Although the total amount of proteins remains unchanged from oviposition to hatching, a 15% reduction in vitellin (VT) content was observed before cellularization, up to the 4th day after egglaying. This observation was correlated to the synthesis of new proteins needed to support early embryo development. Additional 20% of VT was consumed thereafter, mainly at the end of embryogenesis, and in this case VT is probably used as energy source to the older embryo. Altogether, these data indicate different energy sources for maternal and zygotic driven processes.
Yang, Xiaolong; Yu, Zhijun; He, Yanjie; Xu, Xiaoli; Gao, Zhihua; Wang, Hui; Chen, Jie; Liu, Jingze
Vitellin (Vt) was purified from eggs of parthenogenetic bush tick Haemaphysalis longicornis by gel filtration and ion exchange chromatography. Our results revealed that only one single Vt existed in parthenogenetic bush tick, and the purified Vt was proved to be a hemoglycolipoprotein consisting of nine polypeptides with molecular weights of 203, 147, 126, 82, 74, 70, 61, 47 and 31 kDa, respectively. Polyclonal antibody and monoclonal antibody against Vt were produced using the purified Vt. The change in vitellogenin (Vg) and Vt levels over time of the parthenogenetic H. longicornis was established, and the Vg content in haemolymph and Vt in ovary at different feeding or engorgement statuses was also determined using a double antibody sandwich enzyme-linked immunosorbent assay. The Vg level in haemolymph was distinctly increased on the day of engorgement (1.785 mg/mL) and continued to increase until 2nd day post-engorgement (5.611 mg/mL). There was a slight decrease in Vg level after 4 days of engorgement, and a second peak was observed on day 2 post-oviposition (10.774 mg/mL). Subsequently, Vg content continuously decreased and reached a low level on the 10th day post-oviposition. The Vt content in ovary continuously increased once the female reached its critical weight (0.024 mg per female), and reached the maximum level on day 2 post-oviposition (1.942 mg per female). Afterwards, Vt content rapidly decreased.
Jaenson, Thomas G T; Värv, Kairi; Fröjdman, Isabella; Jääskeläinen, Anu; Rundgren, Kaj; Versteirt, Veerle; Estrada-Peña, Agustín; Medlock, Jolyon M; Golovljova, Irina
The tick species Ixodes ricinus and I. persulcatus are of exceptional medical importance in the western and eastern parts, respectively, of the Palaearctic region. In Russia and Finland the range of I. persulcatus has recently increased. In Finland the first records of I. persulcatus are from 2004. The apparent expansion of its range in Finland prompted us to investigate if I. persulcatus also occurs in Sweden. Dog owners and hunters in the coastal areas of northern Sweden provided information about localities where ticks could be present. In May-August 2015 we used the cloth-dragging method in 36 localities potentially harbouring ticks in the Bothnian Bay area, province Norrbotten (NB) of northern Sweden. Further to the south in the provinces Västerbotten (VB) and Uppland (UP) eight localities were similarly investigated. Ixodes persulcatus was detected in 9 of 36 field localities in the Bothnian Bay area. Nymphs, adult males and adult females (n = 46 ticks) of I. persulcatus were present mainly in Alnus incana - Sorbus aucuparia - Picea abies - Pinus sylvestris vegetation communities on islands in the Bothnian Bay. Some of these I. persulcatus populations seem to be the most northerly populations so far recorded of this species. Dog owners asserted that their dogs became tick-infested on these islands for the first time 7-8 years ago. Moose (Alces alces), hares (Lepus timidus), domestic dogs (Canis lupus familiaris) and ground-feeding birds are the most likely carriers dispersing I. persulcatus in this area. All ticks (n = 124) from the more southern provinces of VB and UP were identified as I. ricinus. The geographical range of the taiga tick has recently expanded into northern Sweden. Increased information about prophylactic, anti-tick measures should be directed to people living in or visiting the coastal areas and islands of the Baltic Bay.
Klich, M; Lankester, M W; Wu, K W
Birds that had migrated northward across Lake Superior were captured upon reaching landfall at Thunder Cape (48 degrees 18' N, 88 degrees 56' W) at the southwestern tip of the Sibley Peninsula, northwestern Ontario, from 9 May to 9 June 1995. Twenty-one of 530 birds examined (6 of 55 species) had a total of 34 ticks; 1 blue jay, Cyanocitta cristata, had a northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Four blacklegged tick, Ixodes scapularis Say, larvae were found on an American robin, Turdus migratorius, and 2 on a chipping sparrow, Spizella passerina. This tick was not found on small mammals at Thunder Cape. Twenty-six larvae and a nymph of the rabbit tick, Haemaphysalis leporispalustris (Packard) were found on 1 American robin, 2 Swainson's thrushes, Catharus ustulatus, 1 white-throated sparrow, Zonotrichia albicollis, 1 common yellowthroat, Geothlypis trichas, 1 blue jay, and 12 chipping sparrows. A nymph of H. chordeilis (Packard) occurred on 1 chipping sparrow. Results demonstrate that northward migrating birds transport larvae of I. scapularis to areas of Ontario where the tick does not appear to have become established in small mammal populations. Spring migrants may be more involved in the dispersal of I. scapularis larvae than previously thought. Cooler temperatures and shorter seasons experienced in the more northerly, continental parts of the established distribution of this tick may extend the life cycle, resulting in a predominance of larvae rather than nymphs being acquired by northward-bound birds in early spring. Consequently, the role of spring migrating birds in the northward spread of I. scapularis and of borreliosis should be reevaluated.
Ginsberg, H S; Zhioua, E
Nymphal and adult Ixodes scapularis Say were sampled by flagging at 2 sites on a barrier island, Fire Island, NY, and at 2 sites on the nearby mainland. Nymphal densities did not differ consistently between island and mainland sites, but adult densities were consistently lower on the island. We tested whether lower adult densities on the island resulted from greater nymphal mortality on the island than the mainland, or whether adult ticks on the island were poorly sampled by flagging because they had attached abundantly to deer, which were common on Fire Island. Differential nymphal mortality on islands versus mainland did not explain this difference in adult densities because survival of flat and engorged nymphs in enclosures was the same at island and mainland sites. Ticks were infected by parasitic wasps on the island and not the mainland, but the infection rate (4.3%) was too low to explain the difference in adult tick densities. In contrast, exclusion of deer by game fencing on Fire Island resulted in markedly increased numbers of adult ticks in flagging samples inside compared with samples taken outside the exclosures. Therefore, the scarcity of adult ticks in flagging samples on Fire Island resulted, at least in part, from the ticks being unavailable to flagging samples because they were on deer hosts. Differences in the densities of flagged ticks inside and outside the exclosures were used to estimate the percentage of questing adults on Fire Island that found deer hosts, excluding those that attached to other host species. Approximately 56% of these questing adult ticks found deer hosts in 1995 and 50% found deer hosts in 1996. Therefore, in areas where vertebrate hosts are highly abundant, large proportions of the questing tick population can find hosts. Moreover, comparisons of tick densities at different sites by flagging can be potentially biased by differences in host densities among sites.
Mitra, S S; Buckley, P A; Buckley, F G; Ginsberg, H S
Acquisition of ticks by bird hosts is a central process in the transmission cycles of many tick-borne zoonoses, but tick recruitment by birds has received little direct study. We documented acquisition of Ixodes scapularis Say on birds at Fire Island, NY, by removing ticks from mist-netted birds, and recording the number of ticks on birds recaptured within 4 d of release. Eight bird species acquired at least 0.8 ticks bird(-1) day(-1) during the seasonal peak for at least one age class of I. scapularis. Gray Catbirds, Eastern Towhees, Common Yellowthroats, and Northern Waterthrushes collectively accounted for 83% of all tick acquisitions; and six individuals apportioned among Black-billed Cuckoo, Gray Catbird, Eastern Towhee, and Common Yellowthroat were simultaneously infested with both larvae and nymphs. Bird species with the highest acquisition rates were generally ground foragers, whereas birds that did not acquire ticks in our samples generally foraged above the ground. Tick acquisition by birds did not differ between deciduous and coniferous forests. Among the 15 bird species with the highest recruitment rates, acquisition of nymphs was not correlated with acquisition of larvae. Tick acquisition rates by individual bird species were not correlated with the reservoir competence of those species for Lyme borreliae. However, birds with high tick acquisition rates can contribute large numbers of infected ticks, and thus help maintain the enzootic cycle, even if their levels of reservoir competence are relatively low.
Ginsberg, H S; Ewing, C P
The distributions of Ixodes dammini Spielman, Clifford, Piesman, and Corwin and Lyme disease spirochetes were studied on Fire Island, N.Y. Adult ticks were more common in high-shrub habitats (shrubby vegetation greater than or equal to 1 m high) than in grassy and lowshrub habitats (vegetation less than 1 m) in spring and fall. In the fall, adults were also common in the woods. Adults were more abundant on narrow trails than in nearby vegetation. During the summer, questing nymphs and larvae were far more common in the woods (primarily in leaf litter) than in open grass-shrub habitats. In contrast, the number of nymphs and larvae per white-footed mouse did not differ among habitats, suggesting that mice play a role in tick dispersal. CO2 trap captures of nymphs on trails were not significantly greater than off trails. Most collections of larvae and nymphs had more than one tick, whereas most samples of adults had only one individual. Borrelia burgdorferi infection rates in free-living ticks were 38% (n = 12) to 50% (n = 32) in adults, 32% in nymphs (n = 184), and 0% in larvae (n = 15). The proportion of ticks infected did not differ significantly among habitats. Therefore, during the spring and fall, activities that take place in high-shrub areas or in the woods (e.g., landscaping, trail or brush clearing) involve a high risk of exposure to adult ticks infected with Lyme disease. In late spring to early summer, any activity involving close contact with leaf litter (e.g., playing in the leaves, gathering leaves for camp bedding) results in a high risk of exposure to infected nymphs.
Tunholi-Alves, Vinícius Menezes; Tunholi Alves, Victor Menezes; da Silva, Jairo Pinheiro; Nora Castro, Rosane; Salgueiro, Fernanda Barbosa; Perinotto, Wendell Marcelo de Souza; Gôlo, Patrícia Silva; Camargo, Mariana Guedes; Angelo, Isabele da Costa; Bittencourt, Vânia Rita Elias Pinheiro
Rhipicephalus microplus is an important tick in tropical regions due to the high economic losses caused by its parasitism. Metarhizium anisopliae and Beauveria bassiana are well-known entomopathogenic fungi that can afflict R. microplus ticks. The development of new targets and strategies to control this parasite can be driven by studies of this tick's physiology. Recently, it was reported that when exposed to adverse physiological conditions, ticks can activate fermentative pathways, indicating transition from aerobic to anaerobic metabolism. Nevertheless, the precise mechanism by which entomopathogenic fungi influence R. microplus metabolism has not been clarified, limiting understanding of the tick-fungus association. Thus, the present study aimed to evaluate the effect of infection of ticks by M. anisopliae and B. bassiana on the amount of selected carboxylic acids present in the hemolymph, enabling increased understanding of changes previously reported. The results showed preservation in the concentrations of oxalic, lactic, and pyruvic acids in the hemolymph 24 and 48 h after dropping from cattle; while there were variations in the concentration of these carboxylic acids after infection of female ticks to M. anisopliae and B. bassiana. Significant increases were observed in the concentration of oxalic and lactic acids and significant reduction of pyruvic acid for both observation times (24 and 48 h) after infection by entomopathogenic fungi. These results indicate that B. bassiana and M. anisopliae infection alters the basal metabolism of R. microplus females, resulting in the activation of fermentative pathways.
Mapholi, Ntanganedzeni O; Marufu, Munyaradzi C; Maiwashe, Azwihangwisi; Banga, Cuthbert B; Muchenje, Voster; MacNeil, Michael D; Chimonyo, Michael; Dzama, Kennedy
Ticks and tick-borne disease (TBD) are major challenges to cattle production in the tropics and subtropics. Economic losses associated with ticks amount to billions of dollars annually. Although efforts to eradicate ticks and TBD using chemical control strategies have been implemented in many developing countries for decades, these acaricides are costly, and cattle susceptibility to ticks remains unchanged. Traditional breeding methods, where the farmer selected animals using records to improve the host genetic resistance to ticks (HGRT), are less than fully effective and time consuming. The HGRT has been reported in literature. To date, solutions to fight ticks and TBD are still unclear. Development of single-nucleotide polymorphism (SNP) technologies has created an opportunity to estimate breeding values of animals from DNA samples. The use of SNP technology for genomic selection allows information retrieval from the genotype even before the gene is expressed; thus potentially giving farmers the ability to make selection decisions on HGRT at an earlier age. This review discusses factors that affect HGRT, breeding selection, immunology, and genomic approaches and their application to improve HGRT in order to enhance livestock production. Copyright © 2014. Published by Elsevier GmbH.
Madhav, Nita K; Brownstein, John S; Tsao, Jean I; Fish, Durland
The blacklegged tick, Ixodes scapularis Say, a vector for the agents of Lyme borreliosis and other diseases, has expanded its range dramatically over the past 20 yr. However, the relative contributions of different vertebrate host species to this expansion have remained largely unexplored. To address this issue, we simulated the expansion of a theoretical tick population across a simple landscape by using a deterministic, spatially explicit, cellular automata model. The model incorporates the ecology of ticks and three vertebrate hosts: white-tailed deer, Odocoileus virginianus Zimmermann; white-footed mouse, Peromyscus leucopus Rafinesque; and American robin, Turdus migratorius L. Host contribution to tick dispersal is modeled as a function of tick burden, home range size, and population density. These parameters were determined using published and unpublished data. Our results suggest that 1) hosts with high tick burdens and large home ranges (e.g., deer) play a critical role in I. scapularis range expansion; 2) hosts with small home ranges (e.g., mice) can limit range expansion if they divert a sufficient number of ticks from feeding on more mobile hosts; and (3) birds that migrate annually (e.g., robins) can play a crucial role in tick range expansion.
Zhioua, Elyes; Heyer, Klaus; Browning, M.; Ginsberg, Howard S.; LeBrun, Roger A.
Pathogenicity of the entomopathogenic bacterium Bacillus thuringiensis var. kurstaki de Barjac & Lemille was tested against the black-legged tick, Ixodes scapularis Say. Engorged larvae dipped in a solution of 108 spores per ml showed 96% mortality, 3 wk post-infection. The LC50 value for engorged larvae (concentration required to kill 50% of ticks) was 107 spores/ml. Bacillus thuringiensis shows considerable potential as a microbial control agent for the management of Ixodes scapularis.
Liu, Jian-Nan; Yu, Zhi-Jun; Liu, Li-Meng; Li, Ning-Xin; Wang, Rong-Rong; Zhang, Chun-Mian; Liu, Jing-Ze
Francisella-like endosymbionts (FLEs) with significant homology to Francisella tularensis (γ-proteobacteria) have been characterized in several tick species, whereas knowledge on their distribution and population dynamics in ticks remains meager. Hence, in the current study, we identified a novel Francisella-like endosymbiont (FLEs-Hd) from the tick Haemaphysalis doenitzi and evaluated the putative functions of this symbiont. Results indicated that FLEs-Hd had 100% infection rate and a perfect vertical transmission in H. doenitzi, and that it is distributed in ovaries, malpighian tubules, salivary glands and midguts of the ticks, suggesting that FLEs-Hd presumably is a crucial symbiont of the host without specific tissue tropism. To further explore the function of the symbiont, the population dynamics of FLEs-Hd at each developmental stage of ticks and in tissues at different reproductive statuses were determined by real-time quantitative polymerase chain reaction (real-time qPCR). Results showed that the high density and regular population dynamics of FLEs-Hd appeared in female ovaries, suggesting that the symbiont may provide necessary nutrients or regulators to ensure normal ovary development of ticks. PMID:27731377
Keskin, Adem; Keskin, Aysun; Bursali, Ahmet; Tekin, Saban
In order to identify ticks infesting humans in Corum and Yozgat provinces in Turkey, a total of 2110 ticks representing 14 species were collected on humans, between June and September 2009. Of those, 1551 (687♂, 450♀, 407 nymphs, 7 larvae) were collected from Corum and 559 (330♂, 180♀, 49 nymphs) were collected from Yozgat. The majority of ticks (n = 1121, 53.1 %) was Hyalomma marginatum. Other common ticks infesting humans were Dermacentor marginatus (n = 209, 9.9 %) and Rhipicephalus turanicus sensu lato (n = 145, 6.9 %) in the study area. In addition, a total of 386 immature Hyalomma were found on humans in Corum (335 nymphs, 7 larvae) and Yozgat (44 nymphs). Ixodes laguri and Haemaphysalis erinacei taurica were recorded for the first time in Corum. To the best of our knowledge, this study is the first detailed investigation on ticks infesting humans in Corum and Yozgat, except individual or incidental records. The present study provides useful information for those concerned with ticks and tick-borne diseases in Turkey.
Hugh-Jones, M.; Barre, N.; Nelson, G.; Wehnes, K.; Warner, J.; Garvin, J.; Garris, G.
The feasibility of identifying specific habitats of the African bont tick, Amblyomma variegatum, from Landsat-TM images was investigated by comparing remotely sensed images of visible farms in Grande Terre (Guadeloupe) with field observations made in the same period of time (1986-1987). The different tick habitates could be separated using principal component analysis. The analysis clustered the sites by large and small variance of band values, and by vegetation and moisture indexes. It was found that herds in heterogeneous sites with large variances had more ticks than those in homogeneous or low variance sites. Within the heterogeneous sites, those with high vegetation and moisture indexes had more ticks than those with low values.
Keskin, Adem; Bursali, Ahmet; Kumlutas, Yusuf; Ilgaz, Cetin; Tekin, Saban
Reptiles may contribute to maintaining tick populations by feeding larvae, nymphs, and adults. The life cycles and tick-host associations of many Turkish ticks are still poorly known, and only 3 ixodid tick species have been reported on 7 reptile species in Turkey. In this study, we performed a tick survey on reptiles in the Southeastern Anatolia Region of Turkey. In 2005, 57 reptiles (52 lizards and 5 snakes) comprising 10 species from 5 families were captured and examined for tick infestation. A total of 427 ticks was collected. The majority of ticks found on lizards was the immature stages of Haemaphysalis sulcata, 420 larvae and 4 nymphs. The only adult ticks recorded on the agamid lizard, Laudakia stellio, were Hyalomma aegyptium (1 ♂, 2 ♀). The highest tick infestation rate was recorded on specimens of Timon princeps. This study is the first detailed investigation on ticks infesting reptiles in Turkey. To the best of our knowledge, these tick-host associations have never been documented in the literature.
Silva, Naylene C S; Vale, Vladimir F; Franco, Paula F; Gontijo, Nelder F; Valenzuela, Jesus G; Pereira, Marcos H; Sant'Anna, Mauricio R V; Rodrigues, Daniel S; Lima, Walter S; Fux, Blima; Araujo, Ricardo N
Rhipicephalus (Boophilus) microplus is the main ectoparasite affecting livestock worldwide. For a successful parasitism, ticks need to evade several immune responses of their hosts, including the activation of the complement system. In spite of the importance of R. microplus, previous work only identified one salivary molecule that blocks the complement system. The current study describes complement inhibitory activities induced by R. microplus salivary components and mechanisms elicited by putative salivary proteins on both classical and alternative complement pathways. We found that R. microplus saliva from fully- and partially engorged females was able to inhibit both pathways. Saliva acts strongly at the initial steps of both complement activation pathways. In the classical pathway, the saliva blocked C4 cleavage, and hence, deposition of C4b on the activation surface, suggesting that the inhibition occurs at some point between C1q and C4. In the alternative pathway, saliva acts by binding to initial components of the cascade (C3b and properdin) thereby preventing the C3 convertase formation and reducing C3b production and deposition as well as cleavage of factor B. Saliva has no effect on formation or decay of the C6 to C8 components of the membrane attack complex. The saliva of R. microplus is able to inhibit the early steps of classical and alternative pathways of the complement system. Saliva acts by blocking C4 cleavage and deposition of C4b on the classical pathway activation surface and, in the alternative pathway, saliva bind to initial components of the cascade (C3b and properdin) thereby preventing the C3 convertase formation and the production and deposition of additional C3b.
Johnson, T. L.; Bjork, J. K. H.; Neitzel, D. F.; Dorr, F. M.; Schiffman, E. K.; Eisen, R. J.
Ixodes scapularis Say, the black-legged tick, is the primary vector in the eastern United States of several pathogens causing human diseases including Lyme disease, anaplasmosis, and babesiosis. Over the past two decades, I. scapularis-borne diseases have increased in incidence as well as geographic distribution. Lyme disease exists in two major foci in the United States, one encompassing northeastern states and the other in the Upper Midwest. Minnesota represents a state with an appreciable increase in counties reporting I. scapularis-borne illnesses, suggesting geographic expansion of vector populations in recent years. Recent tick distribution records support this assumption. Here, we used those records to create a fine resolution, subcounty-level distribution model for I. scapularis using variable response curves in addition to tests of variable importance. The model identified 19% of Minnesota as potentially suitable for establishment of the tick and indicated with high accuracy (AUC = 0.863) that the distribution is driven by land cover type, summer precipitation, maximum summer temperatures, and annual temperature variation. We provide updated records of established populations near the northwestern species range limit and present a model that increases our understanding of the potential distribution of I. scapularis in Minnesota. PMID:27026161
Ogrzewalska, Maria; Schwarcz, Kaiser; Bajay, Miklos M; Bajay, Stephanie K; Pinheiro, José B; Zucchi, Maria I; Pinter, Adriano; Labruna, Marcelo B
The hard tick Amblyomma aureolatum (Pallas) is a vector of the bacterium Rickettsia rickettsii, the etiologic agent of Brazilian spotted fever (BSF) in parts of Brazil. Despite its wide distribution in southeastern South America and its public health importance, there is no information about genetic variation of this species that might help to understand the epidemiology of BSF. Using data from eight microsatellite markers and ticks from six localities, we used a population genetics approach to test the hypothesis that tick populations from areas with the presence of R. rickettsii are genetically different from ticks from areas without R. rickettsii Contrary to expectations, we found low genetic structure between studied regions. Thus, the presence of R. rickettsii in the specific area is more likely correlated with ecological and the environmental conditions or due to unknown gene coding regions of A. aureolatum genome that would be related to R. rickettsii infection resistance.
Ogrzewalska, M; Bajay, M M; Schwarcz, K; Bajay, S K; Telles, M P C; Pinheiro, J B; Zucchi, M I; Pinter, A; Labruna, M B
Amblyomma aureolatum (Pallas) is the main vector of the bacterium Rickettsia rickettsii, the etiological agent of Brazilian spotted fever. This disease is the most lethal human spotted fever rickettsiosis in the world. Microsatellite loci were isolated from a dinucleotide-enriched library produced from A. aureolatum sampled in Southeastern Brazil. Eight polymorphic microsatellites were further characterized among 38 individuals sampled from São Paulo metropolitan region. The number of observed alleles ranged from 2 to 9, observed heterozygosity was 0.184-0.647, and expected heterozygosity was 0.251-0.747. Cross-species amplifications suggested that these loci will be useful for other Amblyomma species.
Zhioua, E.; LeBrun, R.A.; Ginsberg, H.S.; Aeschliman, A.
The entomopathogenic nematodes Steinernema carpocapsae (Weiser) and S. glaseri (Steiner) are pathogenic to engorged adult, blacklegged ticks, Ixodes scapularis (Say), but not to unfed females, engorged nymphs, or engorged larvae. Nematodes apparently enter the tick through the genital pore, thus precluding infection of immature ticks. The timing of tick mortality, and overall mortality after 17 d, did not differ between infections by S. carpocapsae and S. glaseri. These nematodes typically do not complete their life cycles or produce infective juveniles in I. scapularis. However, both species successfully produced infective juveniles when the tick body was slit before nematode infection. Mortality of engorged I. scapularis females infected by S. carpocapsae was greater than uninfected controls, but did not vary significantly with nematode concentration (50-3,000 infective juveniles per 5-cm-diameter petri dish). The LC50 was 347.8 infective juveniles per petri dish (5 ticks per dish). Hatched egg masses of infected ticks weighed less than those of uninfected controls. Mortality of infected ticks was greatest between 20 and 30?C, and was lower at 15?C.
Zhioua, E.; Bouattour, A.; Hu, C.M.; Gharbi, M.; Aeschliman, A.; Ginsberg, H.S.; Gern, L.
Free-living adult Ixodes ricinus L. were collected in Amdoun, situated in the Kroumiry mountains in northwestern Tunisia (North Africa). Using direct fluorescence antibody assay, the infection rate of field-collected I. ricinus by Borrelia burgdorferi sensu lato was 30.5% (n = 72). No difference in infection rate was observed between male and female ticks. Spirochetes that had been isolated from I. ricinus from Ain Drahim (Kroumiry Mountains) in 1988 were identified as Borrelia lusitaniae (formerly genospecies PotiB2). This is the first identification of a genospecies of Borrelia burgdorferi sensu lato from the continent of Africa.
Rulison, Eric L.; LeBrun, Roger A.; Ginsberg, Howard S.
Ambient temperature can influence tick development time, and can potentially affect tick interactions with pathogens and with vertebrate hosts. We studied the effect of ambient temperature on duration of attachment of larval blacklegged ticks, Ixodes scapularis Say, to eastern fence lizards, Sceloporus undulatus (Bose & Daudin). Feeding periods of larvae that attached to lizards under preferred temperature conditions for the lizards (WARM treatment: temperatures averaged 36.6°C at the top of the cage and 25.8°C at the bottom, allowing behavioral thermoregulation) were shorter than for larvae on lizards held under cool conditions (COOL treatment temperatures averaged 28.4°C at top of cage and 24.9°C at the bottom). The lizards were infested with larvae four times at roughly monthly intervals. Larval numbers successfully engorging and dropping declined and feeding period was longer after the first infestation.
Ginsberg, H.S.; Zhioua, E.
Nymphal and adult Ixodes scapularis Say were sampled by flagging at 2 sites on a barrier island, Fire Island, NY, and at 2 sites on the nearby mainland. Nymphal densities did not differ consistently between island and mainland sites, but adult densities were consistently lower on the island. We tested whether lower adult densities on the island resulted from greater nymphal mortality on the island than the mainland, or whether adult ticks on the island were poorly sampled by flagging because they had attached abundantly to deer, which were common on Fire Island. Differential nymphal mortality on islands vs. mainland did not explain this difference in adult densities because survival of flat and engorged nymphs in enclosures was the same at island and mainland sites. Ticks were infected by parasitic wasps on the island and not the mainland, but the infection rate (4.3%) was too low to explain the difference in adult tick densities. In contrast, exclusion of deer by game fencing on Fire Island resulted in markedly increased numbers of adult ticks in flagging samples inside compared to samples taken outside the exclosures. Therefore, the scarcity of adult ticks in flagging samples on Fire Island resulted, at least in part, from the ticks being unavailable to flagging samples because they were on deer hosts. Differences in the densities of flagged ticks inside and outside the exclosures were used to estimate the percentage of questing adults on Fire Island that found deer hosts, excluding those that attached to other host species. Approximately 56% of these questing adult ticks found deer hosts in 1995 and 50% found deer hosts in 1996. Therefore, in areas where vertebrate hosts are highly abundant, large proportions of the questing tick population can find hosts. Moreover, comparisons of tick densities at different sites by flagging can potentially be biased by differences in host densities among sites.
Sarani, Moslem; Telmadarraiy, Zakkyeh; Moghaddam, Abdolreza Salahi; Azam, Kamal; Sedaghat, Mohammad Mehdi
Objective To determine the prevalence of ticks on cattle in the mountainous areas of Golestan province and their geographical distribution. Methods In total, 498 animals from 25 herds were selected to search for ticks in 2009-2010. Tick collection was carried out during four seasons, twice per season over a period of 12 month from March 2009 through February 2010 in two districts, Azadshahr and Ramian. Meteorological data were obtained from Iran Meteorological Organization. The geographical points recorded using a Garmin eTrex®H GPS. Results A total of 255 ticks were collected from a total of 219 ruminants including 44 sheep, 63 goats, 99 cows and 13 camels in two districts of the mountainous area of Golestan province, including Azadshahr and Ramian. Five species of ixodid ticks were identified: Rhipicephalus sanguineus (66.5%), Rhipicephalus bursa (4.6%), Hyalomma marginatum (19.9%), Hyalomma anatolicum (6%) and Hyalomma asiaticum (4%). The densities of infestations were calculated for sheep, goats, cows and camels 0.9, 0.79, 0.16 and 0.43 respectively. Seasonal activity of each ixodid tick infesting domestic ruminants was determined. The distribution maps showed ixodid ticks on domestic ruminants, and Rhipicephalus sanguineus were dominant species in the area. Conclusions Such research provides necessary information for human and animal health service mangers to have a better understanding of prevention and control of vector borne diseases especially during the outbreaks. PMID:25183090
Dermacentor albipictus (Packard) is a North American Ixodid tick that parasitizes deer species but also infests livestock. It is a suspected vector of the agent of anaplasmosis in cattle herds, Anaplasma marginale, but its microbial flora and emerging pathogen vector potential remain under-evaluated...
Guglielmone, Alberto A; Nava, Santiago; Mastropaolo, Mariano; Mangold, Atilio J
A study was conducted to investigate the distribution of Amblyomma triste in Argentina under the hypothesis that this tick prevails in riparian localities along the Paraná River and adjacent humid environments from 34° 30' S to 25° 20' S, approximately. Ticks were collected from mammals and vegetation in those environments from November 2008 to October 2012. Additionally, genetic variation was tested from Argentinean, Brazilian, Chilean, and Uruguayan populations of A. triste by comparing sequences of 16S rDNA mitochondrial gene. The hypothesis was not confirmed because A. triste were collected at 36° 16' S, well beyond the southern limit predicted, and the distribution along the banks of the Paraná River was not continuous. The northernmost population of A. triste within Argentina was found at 25° 42' S. Still undetermined abiotic factors and plant communities may play a role in modulating the abundance of A. triste because host availability does not appear to be a restriction factor. The genetic variation among A. triste populations from Argentina, Brazil, and Uruguay indicates that they belong to a unique taxon that is considered bona fide A. triste (type locality Montevideo, Uruguay) while it is unclear if the Chilean population of A. triste is conspecific with the other populations investigated in this study. It would be of importance to compare those genetically homogeneous populations with other populations of alleged A. triste, especially populations established in the Nearctic Zoogeographic Region in Mexico and USA.
Nava, Santiago; Barbieri, Amalia M; Maya, Leticia; Colina, Rodney; Mangold, Atilio J; Labruna, Marcelo B; Venzal, José M
The aim of this work was to describe for the first time the presence of Borrelia burgdorferi sensu lato infecting ticks in Argentina. Unfed specimens of Ixodes pararicinus collected from vegetation in Jujuy Province were tested for Borrelia infection by PCR targeting the gene flagellin (fla), the rrfA-rrlB intergenic spacer region (IGS) and the 16S rDNA (rrs) gene. One male and one female of I. pararicinus collected in Jujuy were found to be positive to Borrelia infection with the three molecular markers tested. Phylogenetically, the Borrelia found in I. pararicinus from Jujuy belongs to the B. burgdorferi s.l complex, and it was similar to one of the genospecies detected in I. aragaoi from Uruguay. Also, this genospecies is closely related to two genospecies known from USA, Borrelia americana and the Borrelia sp. genospecies 1. The epidemiological risk that implies the infection with Borrelia in I. paracinus ticks from Argentina appears to be low because the genospecies detected is not suspected of having clinical relevance and there are no records of Ixodes ticks biting humans in the southern cone of South America. Further studies are needed to assess accurately if there is risk of borreliosis transmitted by ticks in South America.
Ginsberg, Howard S.; LeBrun, Roger A.; Heyer, Klaus; Zhioua, Elyes
The potential for nontarget effects of the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin, when used for biological control of ticks, was assessed in laboratory trials. Fungal pathogenicity was studied against convergent ladybird beetles, Hippodamia convergens Guérin-Méneville, house crickets, Acheta domesticus (L.), and the milkweed bugs Oncopeltus fasciatus (Dallas). Fungal spores applied with a spray tower produced significant mortality in H. convergens and A. domesticus, but effects on O. fasciatus were marginal. Placing treated insects with untreated individuals resulted in mortality from horizontal transmission to untreated beetles and crickets, but not milkweed bugs. Spread of fungal infection in the beetles resulted in mortality on days 4–10 after treatment, while in crickets mortality was on day 2 after treatment, suggesting different levels of pathogenicity and possibly different modes of transmission. Therefore, M. anisopliae varies in pathogenicity to different insects. Inundative applications can potentially affect nontarget species, but M. anisopliae is already widely distributed in North America, so applications for tick control generally would not introduce a novel pathogen into the environment. Pathogenicity in lab trials does not, by itself, demonstrate activity under natural conditions, so field trials are needed to confirm these results and to assess methods to minimize nontarget exposure.
Rhipicephalus sanguineus, commonly known as the brown dog tick, is a three-host tick that feeds primarily on dogs and occasionally on other hosts, including humans. R. sanguineus ticks are widely distributed around the world and they are known vectors of pathogens, such as Babesia canis, Ehrlichia canis, and Rickettsia conorii. The increasing number of cases of human parasitism by R. sanguineus ticks reported in the literature indicates that the interaction between humans and R. sanguineus ticks may be more common than it is actually recognized. The indiscriminate use of acaricides is an emerging problem worldwide and has led to the selection of acaricide resistant tick strains. In this article, the medical and veterinary importance, taxonomy, biology, and ecology of R. sanguineus ticks around the world are reviewed. It also discusses the current strategies for the control of R. sanguineus, highlighting the potential risks associated to the improper use of acaricides, such as environmental pollution and toxicity to humans and other non-target organisms (e.g., tick predators).
Horak, I G; MacIvor, K M; Petney, T N; De Vos, V
Large numbers of birds, wild mammals and domestic stock from a variety of localities within the Republic of South Africa were examined for infestation with the ixodid ticks Amblyomma hebraeum and Amblyomma marmoreum. Every warthog (Phacochoerus aethiopicus), Burchell's zebra (Equus burchelli), impala (Aepyceros melampus) and kudu (Tragelaphus strepsiceros) from the Kruger National Park in the north-eastern Transvaal Lowveld was infested with A. hebraeum. In the eastern Cape Province every helmeted guinea fowl (Numida meleagris), scrub hare (Lepus saxatilis) and kudu from the Andries Vosloo Kudu Reserve; all but 1 of the 22 domestic cattle examined on the farm "Bucklands"; and all Angora goats plus nearly all Boer goats examined on the farm "Brakhill" were infested with this tick. Most animals examined appeared to be good hosts of the immature stages, and the larger the host species the greater the chances of it harbouring large numbers of adult ticks. The largest animals examined, such as eland, buffalo, giraffe and rhinoceros, harboured very large numbers of adult A. hebraeum. No adult A. marmoreum was recovered from any host. However, 50% or more of helmeted guinea fowl and kudu from the Andries Vosloo Kudu Reserve; helmeted guinea fowl, scrub hares and eland (Taurotragus oryx) from the Mountain Zebra National Park; helmeted guinea fowl, kudu, domestic sheep, goats and cattle on the farm "Bucklands", and caracal (Felis caracal) from the Cradock and Southwell areas of the eastern Cape Province were infested with immature A. marmoreum. In the Bontebok National Park in the south-western Cape Province more than 35% of scrub hares, vaal ribbok (Pelea capreolus) and bontebok (Damaliscus dorcas dorcas) were infested with immature ticks.
Background Amblyomma cajennense F. is one of the best known and studied ticks in the New World because of its very wide distribution, its economical importance as pest of domestic ungulates, and its association with a variety of animal and human pathogens. Recent observations, however, have challenged the taxonomic status of this tick and indicated that intraspecific cryptic speciation might be occurring. In the present study, we investigate the evolutionary and demographic history of this tick and examine its genetic structure based on the analyses of three mitochondrial (12SrDNA, d-loop, and COII) and one nuclear (ITS2) genes. Because A. cajennense is characterized by a typical trans-Amazonian distribution, lineage divergence dating is also performed to establish whether genetic diversity can be linked to dated vicariant events which shaped the topology of the Neotropics. Results Total evidence analyses of the concatenated mtDNA and nuclear + mtDNA datasets resulted in well-resolved and fully congruent reconstructions of the relationships within A. cajennense. The phylogenetic analyses consistently found A. cajennense to be monophyletic and to be separated into six genetic units defined by mutually exclusive haplotype compositions and habitat associations. Also, genetic divergence values showed that these lineages are as distinct from each other as recognized separate species of the same genus. The six clades are deeply split and node dating indicates that they started diverging in the middle-late Miocene. Conclusions Behavioral differences and the results of laboratory cross-breeding experiments had already indicated that A. cajennense might be a complex of distinct taxonomic units. The combined and congruent mitochondrial and nuclear genetic evidence from this study reveals that A. cajennense is an assembly of six distinct species which have evolved separately from each other since at least 13.2 million years ago (Mya) in the earliest and 3.3 Mya in the latest lineages. The temporal and spatial diversification modes of the six lineages overlap the phylogeographical history of other organisms with similar extant trans-Amazonian distributions and are consistent with the present prevailing hypothesis that Neotropical diversity often finds its origins in the Miocene, after the Andean uplift changed the topology and consequently the climate and ecology of the Neotropics. PMID:24320199
Sanches, Gustavo S; André, Marcos R; do Prado, Angelo P; Allegretti, Silmara M; Remedio, Rafael N; Nunes, Pablo H; Machado, Rosangela Z; Bechara, Gervásio H; Camargo-Mathias, Maria I
The sloth's giant tick Amblyomma varium Koch, which is a neotropical species that inhabits tropical rainforests, is the largest tick reported to date. The adult stage of this tick parasitizes mammals from the families Bradypodidae and Magalonychidae (Xenarthra) nearly exclusively. This study aimed to describe morphological and histological features of the reproductive system and the oocyte maturation process of this tick species. The ovary of A. varium is a long single tubular organ that is horseshoe-shaped, winding and arranged in the posterior part of the body. Two oviducts are connected to the ovary on each side; these thicken at certain region forming the uterus (common oviduct), followed by a muscular connecting tube, vagina and genital aperture. A large number of oocytes at different stages of development are attached to the ovary wall by the pedicel, as they reach maturity they are released into the ovary lumen and from there to the genital aperture. These oocytes develop simultaneously and asynchronically along the ovary. Amblyomma varium oocytes were classified into five development stages (i.e., I-V), and specific characteristics were observed; the processes of yolk and chorion deposition begin early in oocytes stage II, and oocytes V exhibit a very thick chorion and eggs of a large size. These characteristics are likely adaptations that enhance the survival and the reproductive success of this extremely host-specific tick, which is limited to a particular environment.
The tick Ixodes brunneus Koch is a rare species occurring primarily in North America, where it feeds on many species of passeriform birds. Virtually nothing is known about the questing activity of this tick, although adults often stand with their front legs straight up, suggesting that they quest from a horizontal position. The present study analyzed I. brunneus questing behavior based on field data from drag cloth collections in northern Mississippi, as well as observational laboratory data from 10 I. brunneus ticks released into an experimental "questing apparatus." Ten ticks of a related species, I. scapularis Say, were used for comparison, and there were 3 replications each trial. Eight I. brunneus adults were collected along a nature trail in a northern Mississippi park during 20 total swaths with a drag cloth over a 2-day period (each time 5 swaths in the middle of the trail, with little or no vegetation; and 5 swaths along the edge of the trail, with taller vegetation). All 8 ticks were collected in the middle of the trail in vegetation no taller than 40 mm. In the laboratory experiment, the majority (>70%) of ticks of both species made no attempt to climb the metal or wood artificial stems, but instead they crawled around on the substratum. In 8/30 instances, I. brunneus climbed metal artificial stems to various heights as opposed to 4/30 instances for I. scapularis . Sometimes, ticks of both species seemed to quest at the base of both types of artificial stems. The mean height for questing by I. scapularis on metal stems was 38.2 mm as opposed to 31.8 mm for I. brunneus. Although the mean height was slightly higher for I. scapularis compared with I. brunneus, there was no statistical difference in questing heights observed between the 2 species. Ixodes brunneus and I. scapularis climbed wooden artificial stems in only 2/30 instances for each tick species, again with no statistical difference in questing heights between species. The field observations suggest that I. brunneus quests at ground level; however, laboratory simulations revealed that although the average height climbed was below 40 mm, they sometimes climb artificial stems to greater heights (approximately 50 mm in 4 instances).
Garvin, Stephen D; Noden, Bruce H; Dillwith, Jack W; Fox, Stanley F; Payton, Mark E; Barker, Robert W
Reptiles were collected in nine counties in Oklahoma from September 2002 to May 2004 and examined for Ixodes scapularis (Say) larvae and nymphs to determine seasonal incidence and prevalence of these ticks. In total, 209 reptile specimens consisting of nine species of lizards and seven species of snakes were collected. Plestiodon fasciatus (L.) was the most numerous species collected (55%) followed by Sceloporus undulatus (Latreille) (17%) and Scincella lateralis (Say) (11%). Less than 10 individuals were collected for all remaining reptile species. The infestation prevalence of I. scapularis on all reptile specimens collected was 14% for larvae and 25% for nymphs. Larvae were found on lizards from April until September and peaked in May, while nymphs were found from March until September and peaked in April. I. scapularis larvae (84%) and nymphs (73%) preferentially attached to the axillae/front leg of P. fasciatus. Two chigger species, Eutrombicula splendens (Ewing) and Eutrombicula cinnabaris (Ewing), were found on 2% of the reptiles collected. No ectoparasites, including ticks, were obtained from the seven species of snakes collected. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Nava, Santiago; Venzal, José M; Labruna, Marcelo B; Mastropaolo, Mariano; González, Enrique M; Mangold, Atilio J; Guglielmone, Alberto A
We supply information about hosts and distribution of Amblyomma dubitatum. In addition, we carry out an analysis of genetic divergence among specimens of A. dubitatum from different localities and with respect to other Neotropical Amblyomma species, using sequences of 16S rDNA gene. Although specimens of A. dubitatum were collected on several mammal species as cattle horse, Tapirus terrestris, Mazama gouazoubira, Tayassu pecari, Sus scrofa, Cerdocyon thous, Myocastor coypus, Allouata caraya, Glossophaga soricina and man, most records of immature and adult stages of A. dubitatum were made on Hydrochoerus hydrochaeris, making this rodent the principal host for all parasitic stages of this ticks. Cricetidae rodents (Lundomys molitor, Scapteromys tumidus), opossums (Didelphis albiventris) and vizcacha (Lagostomus maximus) also were recorded as hosts for immature stages. All findings of A. dubitatum correspond to localities of Argentina, Brazil, Paraguay and Uruguay, and they were concentrated in the Biogeographical provinces of Pampa, Chaco, Cerrado, Brazilian Atlantic Forest, Parana Forest and Araucaria angustifolia Forest. The distribution of A. dubitatum is narrower than that of its principal host, therefore environmental variables rather than hosts determine the distributional ranges of this tick. The intraspecific genetic divergence among 16S rDNA sequences of A. dubitatum ticks collected in different localities from Argentina, Brazil and Uruguay was in all cases lower than 0.8%, whereas the differences with the remaining Amblyomma species included in the analysis were always bigger than 6.8%. Thus, the taxonomic status of A. dubitatum along its distribution appears to be certain at the specific level.
Rodrigues, Vinicius da Silva; Garcia, Marcos Valério; Cruz, Breno Cayeiro; Maciel, Willian Giquelin; Zimmermann, Namor Pinheiro; Koller, Wilson Werner; Barros, Jacqueline Cavalcante; Andreotti, Renato
The objective of this study was to evaluate the life cycle and parasitic competence of Dermacentor nitens (Neumann, 1897) on different animal species. Experimental infestations were induced in five specimens each of seven species of possible hosts: rabbits, horses, sheep, cows, guinea pigs, birds and dogs. Rabbits were infested in the ear using artificial feeding chambers, and the horses, sheep, cows and dogs were infested in the ear without feeding chambers. For the infestation of guinea pigs, artificial feeding chambers were fixed on the back. Birds were infested by placing larvae on the back and under the wings without the use of chambers. All animals were inspected daily until the end of the parasitic phase (when the engorged females detached). The average period of engorgement was 25.1days on a horse, with larvae requiring 8days and nymphs 9days to reach engorgement; the average weight of engorged females was 271.4mg; the average weight of egg batches produced was 159.3mg, and the feed conversion rate was 56.8%. On rabbits, the average engorgement period was 27.6days, larvae and nymphs reached engorgement after 7.4 and 11days, respectively, the average weight of an engorged female was 108.4mg and the egg mass was 30.6mg. The feed conversion rate on rabbits was 30%. Cows, sheep, guinea pigs, dogs and birds were not competent hosts, since no engorged females were recovered. Rabbits, when artificially infested, can be used as an alternative host for the maintenance of these ticks in the laboratory. The parasitic specificity of D. nitens for horses was demonstrated in this study.
Ramos, Vanessa do Nascimento; Osava, Carolina Fonseca; Piovezan, Ubiratan; Szabó, Matias Pablo Juan
We herein describe the ambush behavior of Amblyomma sculptum (Berlese 1888), a widespread and epidemiologically important tick in Brazil. Along two years of sampling by visual search in the Brazilian Pantanal, A. sculptum ticks were observed on the vegetation and in the leaf litter. Most of the ticks were observed between 10 and 50cm above ground level and less than five percent of the total were positioned below 10cm, indicating that they are seeking for middle or large-sized hosts. In both seasons, vapor saturation deficit was low during the morning. No significant relationship was found between questing ticks and daytime interval of observation or saturation deficit. However, questing tick numbers seem be higher in the end of the morning, when saturation deficit reaches its peak. Behavioral patterns of A. sculptum ticks observed in Pantanal underscore the occurrence of this tick and human contact at green anthropogenic sites. Considering A. sculptum questing behavior, inferences on human behavioral patterns that enhance or avoid contact with ticks are discussed.
Hornbostel, V.L.; Zhioua, Elyes; Benjamin, Michael A.; Ginsberg, Howard S.; Ostfeld, Richard S.
Effectiveness of the entomopathogenic fungus Metarhizium anisopliae, for controlling nymphal Ixodes scapularis, was tested in laboratory and field trials. In the laboratory, M. anisopliae (Metschnikoff) Sorokin strain ESC1 was moderately pathogenic, with an LC50 of 107 spores/ml and induced 70% mortality at 109 spores/ml. In a field study, however, 109 spores/ml M. anisopliae did not effectively control questing I. scapularis nymphs, and significant differences were not detected in pre- and post-treatment densities. For nymphs collected and returned to the laboratory for observation, mortality was low in treatment groups, ranging from 20 to 36%. To assess whether a chemical acaricide would synergistically enhance pathogenicity of the fungus, we challenged unfed nymphal I. scapularis with combinations of M. anisopliae and permethrin, a relatively safe pyrethroid acaricide, in two separate bioassays. Significant interactions between M. anisopliae and permethrin were not observed, supporting neither synergism nor antagonism.
Ramos, Rafael Antonio Nascimento; Campbell, Bronwyn Evelyn; Whittle, Alice; Lia, Riccardo Paolo; Montarsi, Fabrizio; Parisi, Antonio; Dantas-Torres, Filipe; Wall, Richard; Otranto, Domenico
Natural enemies of ticks include the parasitoid wasp Ixodiphagus hookeri (Hymenoptera: Encyrtidae). The aim of this preliminary study was to investigate the occurrence of I. hookeri DNA in a community of ticks (Ixodes ricinus, Dermacentor marginatus, Hyalomma marginatum, Haemaphysalis inermis and Rhipicephalus turanicus). From May 2010 to March 2012, ticks were collected monthly by dragging and flagging, identified, and 481 adults and 305 nymphs screened molecularly for infection with I. hookeri. Of the samples tested (n=786), 3.1% (n=25) were positive for I. hookeri DNA, 7.2% (n=22) in nymphs and 0.6% (n=3) in adults. I. hookeri DNA was only detected in I. ricinus. This study shows that I. hookeri infests I. ricinus in southern Italy, with nymphs being the main developmental stage affected by this wasp.
Venzal, José Manuel; Estrada-Peña, Agustín; Portillo, Aránzazu; Mangold, Atilio J; Castro, Oscar; de Souza, Carlos G; Félix, María L; Pérez-Martínez, Laura; Santibánez, Sonia; Oteo, José A
Amblyomma triste is the most prevalent tick species reported in human tick bites in Uruguay and has been found to be infected with Rickettsia parkeri, but no other microorganisms have been reported from this tick. A sample of 254 adults of A. triste was collected by flagging on vegetation in suburban areas in southern Uruguay. Pools of five ticks were assembled and a screening for the DNA from the resulting 51 pools was realized by PCR assays using primers for amplifying a fragment of 16S rRNA gene for members of Anaplasmataceae. Seventeen pools were positive (33%) and the sequenciation of the gene fragment amplified revealed the presence of a putative new Alpha-Proteobacterium (denominated Atri-uru). The phylogenetic analysis showed that this microorganism is closely related to the symbiont of I. ricinus denominated 'Candidatus Midichloria mitochondrii' and other associated organisms. This rickettsial symbiont of ticks is included in a recent new clade proposed for the Alpha subclass of the Proteobacteria. The discovery of this bacterium in A. triste is the first evidence of this group of Rickettsiales detected in the Genus Amblyomma, and the first record in South America. Also, in two of 17 positive samples a Gamma-Proteobacterium related to Francisella-like organisms was detected.
of the blue-faced booby (Sula dactylatra melanops) on Hasikiya Island, Arabian Sea (Ixodoidea, Argasidae). Proceedings of the Entomological Society ...1962). In addition to the Journal of Parasitology, the Journal of Medical Entomology and the Annals of the Entomological Society of America were...Annals of the Entomological Society of America, 50, 544–549. Hoogstraal, H. (1958) Bat ticks of the genus Argas (Ixodoidea, Argasidae). 3. The subgenus
Oorebeek, M; Rismiller, P
In 2006, we examined Kangaroo Island kangaroos, Macropusfuliginosusfuliginosus, for ticks. We collected three tick species: Ixodes hirsti Hassall, Hemaphysalis bancrofti Nuttall & Warburton, and Bothriocroton concolor (Neumann). Surprisingly, the specimens included eight females and one nymph of B. concolor, which had previously been considered strictly host specific to the echidna (Tachyglossus sp.). This is the first record of B. concolor on the Kangaroo Island kangaroo.
The Ixodidae include the most common tick species encountered in Europe. The ticks transmit a variety of bacterial and protozoan agents of medical and veterinary significance. The aim of the current work was to investigate distribution of Ixodes ricinus and Dermacentor reticulatus ticks in Kyiv, the...
Nematodes within the Xiphinema americanum species complex are economically important because they vector nepoviruses which cause considerable damage to a variety of agricultural crops. The taxonomy of X. americanum is controversial, with the number of putative species being the subject of debate. Ac...
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...
The Tuckerellidae is the only a phytophagous family within the Tetranychoidea (Acari) that retains the ancestral prostigmatan condition of three nymphal stages during development; however it is only the female developmental sequence that retains a tritonymphal stage. Adult females develop from a tr...
The γ-proteobacterium Francisella tularensis causes seasonal tick-transmitted tularemia outbreaks in natural rabbit hosts and incidental infections in humans in the south-central United States. Although Dermacentor variabilis is considered a primary vector for F. tularensis, Amblyomma americanum is the most abundant tick species in this endemic region. A systematic study of F. tularensis colonization of A. americanum was undertaken to better understand its potential to serve as an overwintering reservoir for F. tularensis and as a bridging vector for human infections. Colony-reared A. americanum were artificially fed F. tularensis subspecies holarctica strain LVS via glass capillaries and colonization levels determined. Capillary-fed larva and nymph were initially infected with 104 CFU/tick which declined prior to molting for both stages, but rebounded post-molting in nymphs and persisted in 53% at 103 to 108 CFU/nymph at 168 days post-capillary feeding (longest sampling time in the study). In contrast, only 18% of adults molted from colonized nymphs maintained LVS colonization at 101 to 105 CFU/adult at 168 days post-capillary feeding (longest sampling time). For adults, LVS initially colonized the gut and disseminated to salivary glands by 24 h and had an ID50 of <5CFU in mice. Francisella tularensis infected the ovaries of gravid females, but transmission to eggs was infrequent and transovarial transmission to hatched larvae was not observed. The prolonged persistence of F. tularensis in A. americanum nymphs supports A. americanum as an overwintering reservoir for F. tularensis from which seasonal epizootics may originate; however, although the rapid dissemination of F. tularensis from gut to salivary glands in adults A. americanum is compatible with intermittent feeding adult males acting as bridging vectors for incidental F. tularensis infections of humans, acquisition of F. tularensis by adults may be unlikely based on adult feeding preference for larger
Because of their small size and tolerance to many of the control procedures used for a wide variety of commodities, Acari species have become one of the fastest, unwanted pest travelers since the beginning of this century. This special issue includes eleven studies on adventive and invasive Acari sp...
Henning, Tyler C; Orr, John M; Smith, Joshua D; Arias, Jorge R; Rasgon, Jason L; Norris, Douglas E
Ticks collected in 2011 were screened for the presence of filarial nematode genetic material, and positive samples were sequenced for analysis. Monanema-like filarial nematode DNA was recently discovered in Amblyomma americanum in northern Virginia, marking the first time genetic material from this parasite has been discovered in ticks in the state. Phylogenetic analysis revealed that this material was directly related to a previously discovered filarial nematode in A. americanum populations in Maryland as well as recently identified parasites in Ixodes scapularis from southern Connecticut. Further study is warranted to visually confirm the presence of these nematodes, characterize their distribution, and determine if these ticks are intermediate hosts.
Woodman, N.; Branstrator, J.W.
In June 1978 the partial skeleton of an American mastodon, Mammut americanum, was salvaged from a drainage ditch in Fulton County, north-central Indiana. The remains were recovered mostly from ca. 170-260 cm below the current land surface in marl overlain by peat and peaty marl. The stratigraphy of the site indicates that the remains were deposited in a small, open-water pond that subsequently filled. The skeleton, which is 41-48% complete, is that of a mature female, ca. 30-34 y old at death based on dental eruption and wear. Postcranial bone measurements indicate that this individual was relatively large for a female. Radiocarbon dating of wood from under the pelvis of the mastodon provided a maximum date of 12,575 ? 260 14C y BP [15,550-13,850 cal y BP] for the animal, which is up to 2575 14C y before the species is believed to have become extinct. Pollen samples from the site corroborate the interpretation that the regional climate was cooler and more humid than at present and supported a mixed spruce-deciduous parkland assemblage. The relatively small size of the molars of this and other mastodons from Indiana supports the hypothesis that late-glacial mastodons - just prior to their extinction - were smaller in size relative to earlier, full-glacial conspecifics. The relationship between molar size and body size is not clear, however, and there may be geographical factors as well as a temporal influence to size variation in these animals.
Mountain goats (Oreamnos americanum) were first introduced into the East Humboldt and Ruby Mountains of Elko County, Nevada in the 1960’s. These contiguous mountain ranges are also home to introduced Rocky Mountain bighorn sheep and native mule deer and are surrounded by both public and private rang...
In addition to damaging trees, the eastern tent caterpillar, (Malacosoma americanum (F.)) is implicated in early fetal loss and late-term abortion in horses. In a field study, we evaluated the potential biological control of eastern tent caterpillar using eastern tent caterpillar nuclear polyhedros...
Brown, H.E.; Yates, K.F.; Dietrich, G.; MacMillan, K.; Graham, C.B.; Reese, S.M.; Helterbrand, Wm. S.; Nicholson, W.L.; Blount, K.; Mead, P.S.; Patrick, S.L.; Eisen, R.J.
In the United States, tickborne diseases occur focally. Missouri represents a major focus of several tickborne diseases that includes spotted fever rickettsiosis, tularemia, and ehrlichiosis. Our study sought to determine the potential risk of human exposure to human-biting vector ticks in this area. We collected ticks in 79 sites in southern Missouri during June 7-10, 2009, which yielded 1,047 adult and 3,585 nymphal Amblyomma americanum, 5 adult Amblyomma maculatum, 19 adult Dermacentor variabilis, and 5 nymphal Ixodes brunneus. Logistic regression analysis showed that areas posing an elevated risk of exposure to A. americanum nymphs or adults were more likely to be classified as forested than grassland, and the probability of being classified as elevated risk increased with increasing relative humidity during the month of June (30-year average). Overall accuracy of each of the two models was greater than 70% and showed that 20% and 30% of the state were classified as elevated risk for human exposure to nymphs and adults, respectively. We also found a significant positive association between heightened acarologic risk and counties reporting tularemia cases. Our study provides an updated distribution map for A. americanum in Missouri and suggests a wide-spread risk of human exposure to A. americanum and their associated pathogens in this region. Copyright ?? 2011 by The American Society of Tropical Medicine and Hygiene.
There are approximately 55,000 described Acari species, accounting for almost half of all known Arachnida species, but total estimated Acari diversity is reckoned to be far greater. One important source of currently hidden Acari diversity is cryptic speciation, which poses challenges to taxonomists ...
Background The 5’ region of cytochrome oxidase I (COI) is the standard marker for DNA barcoding. However, COI has proved to be of limited use in identifying some species, and for some taxa, the coding sequence is not efficiently amplified by PCR. These deficiencies lead to uncertainty as to whether COI is the most suitable barcoding fragment for species identification of ticks. Methods In this study, we directly compared the relative effectiveness of COI, 16S ribosomal DNA (rDNA), nuclear ribosomal internal transcribed spacer 2 (ITS2) and 12S rDNA for tick species identification. A total of 307 sequences from 84 specimens representing eight tick species were acquired by PCR. Besides the 1,834 published sequences of 189 tick species from GenBank and the Barcode of Life Database, 430 unpublished sequences representing 59 tick species were also successfully screened by Bayesian analyses. Thereafter, the performance of the four DNA markers to identify tick species was evaluated by identification success rates given by these markers using nearest neighbour (NN), BLASTn, liberal tree-based or liberal tree-based (+threshold) methods. Results Genetic divergence analyses showed that the intra-specific divergence of each marker was much lower than the inter-specific divergence. Our results indicated that the rates of correct sequence identification for all four markers (COI, 16S rDNA, ITS2, 12S rDNA) were very high (> 96%) when using the NN methodology. We also found that COI was not significantly better than the other markers in terms of its rate of correct sequence identification. Overall, BLASTn and NN methods produced higher rates of correct species identification than that produced by the liberal tree-based methods (+threshold or otherwise). Conclusions As the standard DNA barcode, COI should be the first choice for tick species identification, while 16S rDNA, ITS2, and 12S rDNA could be used when COI does not produce reliable results. Besides, NN and BLASTn are efficient methods for species identification of ticks. PMID:24589289
Siuda, Krzysztof; Nowak, Magdalena; Kedryna, Mariusz
103 specimens of Python regius brought to Poland between October 2002 and March 2004 were examined. Occurrence of tick Aponomma latum was reported from 80.6% of the examined reptiles. 549 specimens of A. latum were collected including 341 males, 149 females and 59 nymphs at the various stage of engorgement. Tick A. latum is frequently transferred beyond its natural range of occurrence--Afrotropical region.
Lerat, Sylvain; Gauci, Rachel; Catford, Jean G; Vierheilig, Horst; Piché, Yves; Lapointe, Line
We investigated in the field the carbon (C) transfer between sugar maple (Acer saccharum) saplings and the spring ephemeral Erythronium americanum via the mycelium of arbuscular mycorrhizal (AM) fungi. Sugar maple saplings and E. americanum plants were planted together in pots placed in the ground of a maple forest in 1999. Ectomycorrhizal yellow birches (Betula alleghaniensis) were added as control plants. In spring 2000, during leaf expansion of sugar maple saplings, the leaves of E. americanum were labelled with (14)CO2. Seven days after labelling, radioactivity was detected in leaves, stem and roots of sugar maples. Specific radioactivity in sugar maples was 13-fold higher than in yellow birches revealing the occurrence of a direct transfer of (14)C between the AM plants. The quantity of (14)C transferred to sugar maple saplings was negatively correlated with the percentage of (14)C allocated to the storage organ of E. americanum. A second labelling was performed in autumn 2000 on sugar maple leaves during annual growth of E. americanum roots. Radioactivity was detected in 7 of 22 E. americanum root systems and absent in yellow birches. These results suggest that AM fungi connecting different understorey species can act as reciprocal C transfer bridges between plant species in relation with the phenology of the plants involved.
Garrett, Jennifer Jane; Kocan, A Alan; Reichard, Mason V; Panciera, Roger J; Bahr, Robert J; Ewing, Sidney A
Each of five adult and four juvenile coyotes (Canis latrans) was exposed to an oral dose of 50 Hepatozoon americanum oocysts recovered from Amblyomma maculatum ticks that previously fed on either naturally infected domestic dogs (Canis familiaris) or naturally infected wild coyotes. All coyotes exposed to H. americanum became infected, regardless of isolate source, and all exhibited mild to moderate clinical disease that simulated American canine hepatozoonosis in naturally infected dogs. At 100 days postexposure, parasitemia was greater in juvenile than adult coyotes (0.9% and 0.3%, respectively); radiographic imaging of femurs revealed moderate exostosis in all juveniles and mild to moderate new bone growth in four of five (80%) adult coyotes. Gross postmortem analysis of bone lesions demonstrated variation between age groups of coyotes but not between isolates of H. americanum. Microscopic evaluation of skeletal muscle revealed that parasite-induced lesions were significantly more numerous (t = 5.0, df = 7, P = 0.001) in juvenile than adult coyotes. Results of this study indicate that juvenile and adult coyotes are equally susceptible to experimental infection with H. americanum isolated from domestic dog and wild coyote sources. The age of coyotes at the time of exposure, and possibly the number of H. americanum oocysts ingested, might influence morbidity and mortality, but it appears that both adult and juvenile coyotes could be reservoirs of H. americanum.
Johnson, E M; Panciera, R J; Allen, K E; Sheets, M E; Beal, J D; Ewing, S A; Little, S E
The range of American canine hepatozoonosis (ACH) is expanding from the southern USA northward. Transmission of Hepatozoon americanum occurs by ingestion of infected Gulf Coast ticks, Amblyomma maculatum. The source of the protozoan for the tick remains undetermined; infected dogs are unusual hosts for the tick. Compare possible sources of infection by field investigations of 2 multiple-dog outbreaks of ACH. Twenty-eight privately owned dogs (Canis familiaris), 1 coyote (Canis latrans), 31 wild-trapped cotton rats (Sigmodon hispidus), 24 wild-trapped field mice (Peromyscus leucopus), and 9 wild-caught rabbits (Sylvilagus spp.) from sites in eastern Oklahoma were monitored for hepatozoonosis. Six laboratory-raised cotton rats (S. hispidus), 6 Sprague-Dawley rats (Rattus norvegicus), 6 C57BL/6J-Lystbg-J/J mice (Mus musculus), 6 outbred white mice (M. musculus), 6 New Zealand white rabbits (Oryctolagus cuniculus), and 2 dogs were acquired through commercial vendors for experimental transmission trials of H. americanum. Four of 15 dogs in a rural neighborhood and 5/12 hunting Beagles were confirmed to be infected by blood smear examination, muscle biopsy, and polymerase chain reaction assay of the 18S rRNA gene of Hepatozoon species. Histories and tick host preferences led to field collections of common prey of canids and experimental transmission trials of H. americanum to selected prey (M. musculus, S. hispidus, R. norvegicus, and O. cuniculus). Dogs with ready access to prey (4/15 dogs) or that were fed prey retrieved from hunts (5/12 hunting Beagles) became infected, providing evidence that predation is an important epidemiologic component of ACH infection. Experimental transmission studies identified a quiescent, infectious stage (cystozoite) of the parasite that provides an alternate mode of transmission to canids through predation, demonstrating that cotton rats, mice, and rabbits but not brown rats may act as paratenic hosts of H. americanum. Predation of prey
The Xiphinema americanum group contains over two-dozen different species of nematode. They are economically important because they vector nepoviruses, which cause damage to several crops. Taxonomic differentiation among species of the X. americanum complex is problematic because many of the species ...
The Genus Ixodes (Acari: Ixodidae) in Mexico: Adult Identification Keys, Diagnoses, Hosts, and Distribution (El genero Ixodes (Acari: Ixodidae) en Mexico: claves de identificacion para adultos, diagnosis, huespedes y distribucion)
Revista Mexicana de Biodiversidad 81: 289- 298, 2010 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection...internal spur of coxa I overlapping anterior margin of coxa II .................I. tovari Revista Mexicana de Biodiversidad 80: 289- 298, 2010...Revista Mexicana de Biodiversidad 80: 289- 298, 2010 293 I with internal and external spurs about equal in length; coxae II-IV with small
Kim, Tae Kwon; Tirloni, Lucas; Radulovic, Zeljko; Lewis, Lauren; Bakshi, Mariam; Hill, Creston; da Silva Vaz, Itabajara; Logullo, Carlos; Termignoni, Carlos; Mulenga, Albert
Tick saliva serine protease inhibitors (serpins) facilitate tick blood meal feeding through inhibition of protease mediators of host defense pathways. We previously identified a highly conserved Amblyomma americanum serpin 19 that is characterised by its reactive center loop being 100% conserved in ixodid ticks. In this study, biochemical characterisation reveals that the ubiquitously transcribed A. americanum serpin 19 is an anti-coagulant protein, inhibiting the activity of five of the eight serine protease blood clotting factors. Pichia pastoris-expressed recombinant (r) A. americanum serpin 19 inhibits the enzyme activity of trypsin, plasmin and blood clotting factors (f) Xa and XIa, with stoichiometry of inhibition estimated at 5.1, 9.4, 23.8 and 28, respectively. Similar to typical inhibitory serpins, recombinant A. americanum serpin 19 forms irreversible complexes with trypsin, fXa and fXIa. At a higher molar excess of recombinant A. americanum serpin 19, fXIIa is inhibited by 82.5%, and thrombin (fIIa), fIXa, chymotrypsin and tryptase are inhibited moderately by 14-29%. In anti-hemostatic functional assays, recombinant A. americanum serpin 19 inhibits thrombin but not ADP and cathepsin G activated platelet aggregation, delays clotting in recalcification and thrombin time assays by up to 250s, and up to 40s in the activated partial thromboplastin time assay. Given A. americanum serpin 19 high cross-tick species conservation, and specific reactivity of recombinant A. americanum serpin 19 with antibodies to A. americanum tick saliva proteins, we conclude that recombinant A. americanum serpin 19 is a potential candidate for development of a universal tick vaccine.
Raghavan, Ram K.; Goodin, Douglas G.; Hanzlicek, Gregg A.; Zolnerowich, Gregory; Dryden, Michael W.; Anderson, Gary A.; Ganta, Roman R.
Abstract The potential distribution of Amblyomma americanum ticks in Kansas was modeled using maximum entropy (MaxEnt) approaches based on museum and field-collected species occurrence data. Various bioclimatic variables were used in the model as potentially influential factors affecting the A. americanum niche. Following reduction of dimensionality among predictor variables using principal components analysis, which revealed that the first two principal axes explain over 87% of the variance, the model indicated that suitable conditions for this medically important tick species cover a larger area in Kansas than currently believed. Soil moisture, temperature, and precipitation were highly correlated with the first two principal components and were influential factors in the A. americanum ecological niche. Assuming that the niche estimated in this study covers the occupied distribution, which needs to be further confirmed by systematic surveys, human exposure to this known disease vector may be considerably under-appreciated in the state. PMID:26824880
Wright, S A; Lane, R S; Clover, J R
To investigate the reservoir potential of the southern alligator lizard, Elgaria multicarinata (Blainville), for the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, 14 lizards were collected from 1 county on each side of the northern Central Valley of California. Seven animals were collected from a Placer County site (Drivers Flat) and a Yolo County site (Cache Creek) where B. burgdorferi had been isolated previously from Ixodes pacificus Cooley & Kohls. Overall, the mean abundance of I. pacificus on all 14 lizards was 34.1 (range, 3-63) for larvae and 11.0 (range, 1-28) for nymphs. In captivity, field-attached I. pacificus larvae and nymphs required, on average, 12.6 (range, 1-37) and 14.4 (range, 5-44) d to feed to repletion, respectively. The prevalence of B. burgdorferi infection in host-seeking I. pacificus nymphs was 1.4% in Cache Creek Canyon and 9.9% in Drivers Flat. Attempts to isolate spirochetes from lizard blood or ticks that had fed on lizards and subsequently molted were unsuccessful as were efforts to cultivate spirochetes in lizard sera. These data suggest that the southern alligator lizard is not a competent reservoir for B. burgdorferi, although it is an important host for I. pacificus subadults.
Wellington, Kevin W; Leboho, Tlabo; Sakong, Bellonah M; Adenubi, Olubukola T; Eloff, Jacobus N; Fouche, Gerda
The goal of our research is to develop a lower cost eco-friendly tick control method because acaricides that are commonly used to control ticks are often toxic, harmful to the environment or too expensive for resource-limited farmers. Acetone and ethanol extracts were prepared and their acaricidal activities determined against the southern cattle tick, Rhipicephalus (Boophilus) microplus. A 1% solution of each of the plant extracts was prepared for efficacy testing using the adapted Shaw Larval Immersion Test (SLIT). The acetone stem extract from Cissus quadrangularis (Vitaceae) and the ethanol leaf and flower extract from Calpurnia aurea (Fabaceae) had potent activity like that of the commercial acaricide, chlorfenvinphos [corrected mortality (CM)=100.0%]. The ethanol extracts of the stem of C. quadrangularis (CM=98.9%) and that of the roots, leaves and fruit of Senna italica subsp arachoides (CM=96.7%) also had good acaricidal activity. There is potential for the development of botanicals as natural acaricides against R. (B.) microplus that can be used commercially to protect animals against tick infestation. Further studies to isolate the acaricidal active compounds and to determine the environmental fate, species toxicity and skin toxicity of these plants species are, however, required before they can be considered as a treatment against ticks. Copyright © 2016 Elsevier B.V. All rights reserved.
Markowski, D.; Hyland, K.E.; Ginsberg, H.S.
Larval blacklegged ticks, Ixodes scapularis, were collected from white-footed mice, Peromyscus leucopus, on Prudence Island (where Microtus pennsylavanicus were not captured) and from meadow voles, M. pennsylvanicus, on Patience Island (where P. leucopus was absent) in Narragansett Bay, Rhode Island from June to October 1992. Ixodes scapularis larvae were also collected by flagging in the vicinity of host captures. On both islands, the relative density of larvae changed from July to September in samples from hosts, but not in flagging samples. Consequently, different sampling techniques can give different assessments of tick populations. Larvae were highly aggregated on both of the host species throughout the sampling period. As the mean relative density of larvae increased in the environment (based on flagging samples), larvae on the hosts became more dense and more crowded. Increased densities of larvae in the environment were not correlated with increased patchiness in the distribution of larvae among host animals on either island. Changes in the spatial distribution of larval I. scapularis on each host species had similar trends as larval densities and distributions within the environment. These results suggest that M. pennsylvanicus can serve as an alternative host for immature I. scapularis in a P. leucopus-free environment and have similar distributional characteristics.
Guerrero, F D; Davey, R B; Miller, R J
A polymerase chain reaction-based assay was developed to detect the presence of a pyrethroid resistance-associated amino acid substitution in Boophilus microplus (Canestrini). The assay uses a simple method for the extraction of genomic DNA from individual larvae and genotypes individuals for the presence of a Phe-->Ile amino acid substitution in the S6 transmembrane segment of domain III of the para-like sodium channel, clearly distinguishing heterozygotes from homozygotes. High frequencies for this amino acid substitution were found in the Corrales and San Felipe strains, which have target site insensitivity mechanisms for pyrethroid resistance. The Caporal resistant strain contained lower yet substantial numbers of amino acid-substituted alleles. Low amino acid substitution frequencies were found in the susceptible reference Gonzales strain and the Coatzacoalcos strain, which has metabolic esterase-mediated pyrethroid resistance. The amino acid substitution was not found in six other strains that were susceptible to pyrethroids.
Schulze, Terry L; Jordan, Robert A; Hung, Robert W; Puelle, Rose S; Markowski, Daniel; Chomsky, Martin S
Using polymerase chain reaction, we analyzed 529 Ixodes scapularis Say adults collected from 16 of New Jersey's 21 counties for the presence of Borrelia burgdorferi, the etiological agent of Lyme disease. Overall, 261 (49.3%) were positive. B. burgdorferi was detected in ticks obtained from each county and from 53 of the 58 (93.1%) municipalities surveyed. The observed statewide prevalence in New Jersey is similar to those reported from other northeastern and mid-Atlantic states.
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...
Synergistic effects of verbutin, a member of aryl alkynyl derivatives, to three commonly used acaricides were evaluated with the modified Food and Agricultural Organization Larval Packet Test (FAO-LPT) against both susceptible and resistant strains of the southern cattle tick Rhipicephalus (Boophilu...
Rhipicephalus sanguineus (Latreille), the brown dog tick, is a veterinary canine and urban pest. These ticks have been found to develop permethrin resistance and fipronil tolerance, two commonly used acaricides. We developed a discriminating concentration that can be used to rapidly detect permethri...
Remedio, R N; Sampieri, B R; Vendramini, M C R; Souza, N M; Anholeto, L A; Denardo, T A G B; Camargo-Mathias, M I
The intestinal epithelial cells of ticks are fundamental for their full feeding and reproductive success, besides being considered important sites for the development of pathogens. Rhipicephalus sanguineus ticks are known for their great medical and veterinary importance, and for this reason, the knowledge of their intestinal morphology may provide relevant subsidies for the control of these animals, either by direct acaricidal action over these cells or by the production of vaccines. Therefore, this study aimed to describe the midgut morphology of male and female R. sanguineus ticks in different feeding stages, by means of histological analysis. Significant differences were observed between the genders, and such alterations may refer mainly to the distinct demands for nutrients, much higher in females, which need to develop and carry out the egg-laying process. In general, the midgut is coated by a thin muscle layer and presents a pseudostratified epithelium, in which two basic types of cells can be observed, connected to a basal membrane-generative or stem and digestive cells. The latter was classified as follows: residual, deriving from the phase anterior to ecdysis; pinocytic, with vesicles containing liquid or pre-digested components of blood; phagocytic, with entire cells or remnants of nuclear material inside cytoplasmic vesicles; and mature, free in the lumen. Digestion is presumably intracellular and asynchronous and corresponds to a process which starts with the differentiation of generative cells into pinocytic digestive cells, which subsequently start to phagocytize intact blood cells and finally detach from the epithelium, being eliminated with feces.
Ma, Miling; Guan, Guiquan; Liu, Qing; Dang, Zhisheng; Liu, Aihong; Ren, Qiaoyun; Liu, Zhijie; Li, Youquan; Chen, Ze; Liu, Junlong; Yang, Jifei; Yin, Hong; Luo, Jianxun
Currently, the most efficient and widely used method for tick control is the application of acaricides, especially deltamethrin and alpha-cypermethrin, two pyrethroids with neurotoxic action. In this study, the in vitro efficacy of deltamethrin and alpha-cypermethrin was assessed on engorged female Haemaphysalis qinghaiensis ticks. An in vitro bioassay (adult immersion test) was carried out to determine the LC (lethal concentration) 50 and LC90 of both compounds, calculated by probit analysis. The LC50 and LC90 values of deltamethrin and alpha-cypermethrin were 5.67 (LC50) and 51.72ppm (LC90), and 166.56 (LC50) and 1366.69ppm (LC90), respectively. This study provides important information on the efficacy of deltamethrin and alpha-cypermethrin for the control of H. qinghaiensis. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.
Nelson, Suzanne L; Durden, Lance A; Reuter, Jon D
Ticks parasitizing introduced white-tailed deer, Odocoileus virginianus (Zimmermann), on St. John, U.S. Virgin Islands, were recorded during and after drought conditions. Tick infestation prevalences were 22% at the start of the drought (July 2015), 66% at the height of the drought (March 2016), and 35% after the drought had ended (July 2016; n = 67 deer). Samples of ticks from 22 tranquilized deer in July 2016 revealed the presence of two species, the southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), and the tropical horse tick, Dermacentor (Anocentor) nitens Neumann. Both tick species have considerable veterinary importance, especially for cattle and horses, respectively, as nuisance biters and also as vectors of parasitic piroplasms or of Anaplasma marginale Theiler. All 22 deer examined were infested by R. microplus, whereas 14 (64%) of the samples also included specimens of D. nitens. Because of the large numbers of ticks recorded, wild deer on St. John could develop associated health problems (pruritis, alopecia, anemia, low weight gain, tick-borne pathogens and parasites) and could also serve as a source of these ticks for cattle and horses. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
M.E. (2008) Rickettsia parkeri rickettsiosis and its clinical distinction from Rocky Mountain spotted fever . Clinical Infectious Diseases, 47...collected specimens for the presence of Rickettsia parkeri, the causative agent of Tidewater spotted fever in humans (Jiang et al. 2012). The collection
Tabari, Mohaddeseh Abouhosseini; Youssefi, Mohammad Reza; Maggi, Filippo; Benelli, Giovanni
The castor bean tick, Ixodes ricinus, is a species of medical and veterinary importance. The use of synthetic acaricides for tick control has led to development of resistance, residues in the environment and animal products, and public health concerns. In this regard, plant essential oils and their main constituents represent an appealing alternative strategy to combat ticks. The phenols thymol and carvacrol and the alcohol linalool are monoterpenoids occurring in essential oils of several aromatic and medicinal plants, such as thyme, oregano, savory, lavender and coriander. Recent studies have shown toxicity of these monoterpenoids against selected mosquito vectors and other arthropod pests. However, information on their bioactivity on I. ricinus is not available. On this basis, here we evaluated the ovicidal, larvicidal and repellency effects of these compounds against I. ricinus. Concentrations of 0.25, 0.5, 1, 2 and 5% were sprayed on the egg masses, then hatching rates were noted. Larvicidal assays were conducted on unengorged larvae, following the larval packet technique. The repellency was determined by measuring the vertical migration behavior of ticks in laboratory conditions. Carvacrol and thymol at all concentrations tested led to a significant hatching decrease, showing an efficacy higher than permethrin, whereas linalool did not cause any significant effect. In the larvae treated with carvacrol and thymol (1, 2 and 5%), mortality rates reached 100% after 24h, showing a larvicidal efficacy higher than permethrin, whereas no effect was seen in the larval groups treated with linalool. Carvacrol and thymol at all concentrations tested showed >90% repellency on I. ricinus. Linalool was scarcely effective (50.24% repellency) only at the concentration of 5%. Overall, based on these results, the phenols carvacrol and thymol can be considered as candidate ingredients for the development of novel acaricidal formulations to control the populations of I. ricinus and the spread of related tick-borne diseases. Copyright © 2017 Elsevier B.V. All rights reserved.
Santos-Silva, Maria Margarida; Almeida, Victor Carlos; Bacellar, Fátima; Dumler, John Stephen
A total of 278 Ixodes ticks, collected from Madeira Island and Setúbal District, mainland Portugal, were examined by polymerase chain reaction (PCR) for the presence of Anaplasma phagocytophilum. Six (4%) of 142 Ixodes ricinus nymphs collected in Madeira Island and 1 nymph and 1 male (2%) of 93 I. ventalloi collected in Setúbal District tested positive for A. phagocytophilum msp2 genes or rrs. Infection was not detected among 43 I. ricinus on mainland Portugal. All PCR products were confirmed by nucleotide sequencing to be identical or to be most closely related to A. phagocytophilum. To our knowledge, this is the first evidence of A. phagocytophilum in ticks from Setúbal District, mainland Portugal, and the first documentation of Anaplasma infection in I. ventalloi. Moreover, these findings confirm the persistence of A. phagocytophilum in Madeira Island's I. ricinus. PMID:15498168
Santos, Ana Sofia; Santos-Silva, Maria Margarida; Almeida, Victor Carlos; Bacellar, Fátima; Dumler, John Stephen
A total of 278 Ixodes ticks, collected from Madeira Island and Setubal District, mainland Portugal, were examined by polymerase chain reaction (PCR) for the presence of Anaplasma phagocytophilum. Six (4%) of 142 Ixodes ricinus nymphs collected in Madeira Island and 1 nymph and 1 male (2%) of 93 I. ventalloi collected in Setubal District tested positive for A. phagocytophilum msp2 genes or rrs. Infection was not detected among 43 I. ricinus on mainland Portugal. All PCR products were confirmed by nucleotide sequencing to be identical or to be most closely related to A. phagocytophilum. To our knowledge, this is the first evidence of A. phagocytophilum in ticks from Setubal District, mainland Portugal, and the first documentation of Anaplasma infection in I. ventalloi. Moreover, these findings confirm the persistence of A. phagocytophilum in Madeira Island's I. ricinus.
Hexane extract of chinaberry, Melia azedarach L., unripe fruits obtained from different municipalities of Goias state in Brazil were evaluated on the southern cattle fever tick, Rhipicephalus microplus (Canestrini), engorged females. Hexanic extracts were assayed in decreasing concentrations from 0....
Flores-Fernández, José Miguel; Gutiérrez-Ortega, Abel; Padilla-Camberos, Eduardo; Rosario-Cruz, Rodrigo; Hernández-Gutiérrez, Rodolfo; Martínez-Velázquez, Moisés
The cattle tick Rhipicephalus (Boophilus) microplus is the most economically important ectoparasite affecting the cattle industry in tropical and subtropical areas around the world. The principal method of tick control has relied mainly on the use of chemical acaricides, including ivermectin; however, cattle tick populations resistant to ivermectin have recently been reported in Brazil, Mexico, and Uruguay. Currently, the molecular basis for ivermectin susceptibility and resistance are not well understood in R. microplus. This prompted us to search for potential molecular targets for ivermectin. Here, we report the cloning and molecular characterization of a R. microplus glycine-like receptor (RmGlyR) gene. The characterized mRNA encodes for a 464-amino acid polypeptide, which contains features common to ligand-gated ion channels, such as a large N-terminal extracellular domain, four transmembrane domains, a large intracellular loop and a short C-terminal extracellular domain. The deduced amino acid sequence showed around 30% identity to GlyRs from some invertebrate and vertebrate organisms. The polypeptide also contains the PAR motif, which is important for forming anion channels, and a conserved glycine residue at the third transmembrane domain, which is essential for high ivermectin sensitivity. PCR analyses showed that RmGlyR is expressed at egg, larval and adult developmental stages. Our findings suggest that the deduced receptor is an additional molecular target to ivermectin and it might be involved in ivermectin resistance in R. microplus.
Laboratory test were carried out on larvae and adults of the cattle tick, Rhipicephalus (Boophilus) microplus, to determine fipronil toxicity. Adult immersion test (AIT), larval immersion test (LIT) and larval packet test (LPT) were standardized using susceptible strain (Mozo). Curves dose-response ...
Eiden, Amanda L; Kaufman, Phillip E; Allan, Sandra A; Oi, Faith
Rhipicephalus sanguineus (Latreille), the brown dog tick, is a veterinary canine and urban pest. These ticks have been found to develop resistance and tolerance to the two commonly used acaricides permethrin and fipronil respectively. We have developed a discriminating concentration that can be used for rapid detection of permethrin and fipronil resistance in brown dog tick populations. The availability of a discriminating concentration for the brown dog tick provides an inexpensive and rapid resistance diagnostic technique that can be used to guide tick management plans for companion animals and aid in the selection of environmental treatment options. Establishing the discriminating concentration for permethrin and fipronil in brown dog ticks enables a resistant:susceptible screening. For permethrin the discriminating concentration was set at 0.19%, and for fipronil at 0.15%. Three additional diagnostic concentrations were chosen to evaluate resistance levels when larval tick numbers were available for screening. Future tick submissions from residences and kennel facilities can be subjected to a single chemical concentration to diagnose resistance, which minimizes time, costs and tick rearing requirements and guides effective control plans. With the standardized use of larval ticks, a client-submission quantity of ideally five engorged females would provide sufficient larval numbers to utilize this technique. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.
Bertrand, M R; Wilson, M L
The effects of habitat and microclimate on survival of unfed nymphal black-legged ticks, Ixodes scapularis Say (approximately I. damnini Spielman, Clifford, Piesman & Corwin), were studied under natural conditions in southcentral and northwestern Connecticut. At both coastal and inland locations, survival of 3 groups of 20 wild-caught questing nymphs placed in nylon mesh bags was monitored in each of 3 different habitats (field, forest canopy, and forest/field edge) during summer 1995. Simultaneously, soil temperature, ground-level air temperature, and relative humidity were measured continuously within each habitat at both sites. The number of ticks surviving in each habitat was monitored weekly. Average daily survival rates of nymphs were related inversely to soil temperature but were not related to air temperature or humidity. Overall, nymphal ticks at the inland site survived significantly longer than those at the coastal site; however, no significant differences in mortality rates were found among habitats. These results suggest that inland environmental conditions are suitable for lengthy survival of unfed nymphal I. scapularis in regions where this tick is not yet abundant.
Hernández-A, F; Teel, P D; Corson, M S; Grant, W E
Ranchers in Venezuela historically have controlled the cattle-fever tick, Boophilus microplus (Canestrini), with acaricide treatments of cattle but no technical planning. We developed a simulation model to evaluate cattle-tick population dynamics in systematic pasture rotation systems and Integrated Pest Management (IPM) approaches to managing ticks in the tropical dry-forest ecological zone of Venezuela. Model output showed five generations of cattle-ticks produced each year throughout the dry and rainy seasons that occur in this zone. Sensitivity analyses showed disproportionately large changes in on-host B. microplus populations in response to small changes in larval mortality rates, such as those resulting from differences in the innate resistance of cattle to tick parasitism. Simulation results with 1-6 pasture systems suggest that adjusting the graze:rest sequence with systematic rotation among 4-6 pastures could suppress, but not eradicate, tick populations.
Lane, Robert S.; Mun, Jeomhee; Stubbs, Harrison A.
The nymph of the western black-legged tick (Ixodes pacificus) is an important bridging vector of the Lyme disease spirochete (Borrelia burgdorferi) to humans in the far-western United States. The previously unknown dispersal capabilities of this life stage were studied in relation to logs, tree trunks, and adjacent leaf-litter areas in a mixed hardwood forest using mark-release-recapture methods. In two spatially and temporally well-spaced trials involving logs, the estimated mean distances that nymphs dispersed ranged from ≈0.04 to 0.20 m/day on logs vs 0.11 to 0.72 m/day in litter. Prior to recapture in either trial and within the confines of the sampling grids, the greatest estimated dispersal distances by individual nymphs released on logs, and in litter 0.5 m or 1.5 m from logs, were 2.4, 3.0, and 3.0 m, respectively. Nymphs released on logs or litter tended to remain within the same biotopes in which they were freed while host-seeking. In two simultaneous trials involving trunks spaced close-at-hand, nymphs released at the trunk/litter interface on all four aspects collectively dispersed a mean of 0.353 m/day on trunks vs 0.175 m/day in litter. In either trial, the greatest distances that recaptured nymphs climbed trunks, or dispersed in litter in an encircling 3-m grid, were 1.55 m and 2.97 m, respectively. Nymphs ascending trunks did not exhibit a preference for any one aspect, and the B. burgdorferi-infection prevalences in nymphs that climbed trunks (3.2–4.0%) did not differ significantly from those that moved horizontally into litter (10.5–17.6%). We conclude that I. pacificus nymphs use an ambush host-seeking strategy; that they disperse slowly in all biotopes studied; that they usually continue to host-seek in or on whatever substratum they access initially; and that B. burgdorferi-infected nymphs are as likely to move horizontally as vertically when offered a choice. PMID:20352083
Acaricidal activity of organophosphate (OP) and carbamate acaricides is believed to result from inhibition of acetylcholinesterase (AChE). Previous studies in Rhipicephalus (Boophilus) microplus demonstrated the presence of three presumptive AChE genes (BmAChEs). Biochemical characterization of re...
Tagliapietra, V; Rosà, R; Arnoldi, D; Cagnacci, F; Capelli, G; Montarsi, F; Hauffe, H C; Rizzoli, A
The wood tick Ixodes ricinus, one of the most common arthropod-borne disease vectors, is of increasing relevance for human and animal health in Europe. The aim of this study was to determine the relative contribution of several abiotic and biotic factors potentially affecting questing activity and local abundance of I. ricinus in Italy, considering the scale at which these factors interact with the host-seeking ticks. Within EDEN, a large-scale EU collaborative project on eco-epidemiology of vector-borne diseases, we collected questing ticks for three consecutive years using a standard protocol at eleven sites in the Italian Alps and Apennines. A total of 25 447 I. ricinus were collected. All sites showed the same annual pattern of tick activity (bimodal for nymphs and unimodal for larvae and adults), although the abundance of nymphs was statistically different between sites and years. A Generalized Linear Mixed Model and a Linear Mixed Model fitted to data for nymphs, showed that while the principal variables affecting the local abundance of questing ticks were saturation deficit (an index combining temperature and relative humidity) and red deer density, the most important variable affecting questing nymph activity was saturation deficit. As for the timing of seasonal emergence, we confirmed that the threshold temperature at this latitude for larvae is 10°C (mean maximum) while that for nymphs is 8°C.
Yu, Zhi-Jun; Lu, Yu-Lan; Yang, Xiao-Long; Chen, Jie; Wang, Hui; Wang, Duo; Liu, Jing-Ze
The survival of overwintering ticks, is critical for their subsequent population dynamics in the spring, and consequent transmission of tick-borne diseases. Survival is largely influenced by the severity of the winter temperatures and their degree of cold hardiness at the overwintering stage. The bush tick Haemaphysalis longicornis, is widely distributed in China, and can transmit various pathogens that pose serious medical/veterinary problems. In the present study we investigated the effect of low temperature stress to tick survival, super-cooling point and body content of water, glycerol and total protein. After various temperature acclimations, the super-cooling point was measured by Ni/CrNi-thermocouples with a precision temperature recorder. Water content was determined from weight loss of the sample exposed to 60°C for 48 h. Glycerol content was determined using Free Glycerol Reagent as directed by the manufacturer, and total protein was determined using the Bradford assay. The 50% mortality temperatures for the adults and nymphs were -13.7°C and -15.2°C, respectively; and the discriminating temperatures for the adults and nymphs were -16.0°C and -17.0°C, respectively. The super-cooling points of the adults and nymphs were -19.0°C and -22.7°C, respectively. The water content of adult H. longicornis decreased substantially after acclimation at 0°C for 10 d, whereas the nymphs decreased after acclimation at 0°C for 20 d, and the glycerol and proteins of both nymphs and adults were significantly increased (p < 0.01) when stressed at 0°C for 10 d. In H. longicornis, low temperature stress can enhance its cold hardiness and trigger appropriate responses, including reducing water content, and increasing glycerol and total protein content.
Hornok, Sándor; Görföl, Tamás; Estók, Péter; Tu, Vuong Tan; Kontschán, Jenő
In a recent study on ixodid bat ticks from Eurasia, a high genetic difference was found between Ixodes vespertilionis from Europe and Vietnam. Accordingly, it was proposed that I. vespertilionis is a species complex, with at least one additional, hitherto undescribed species. The aim of the present study was to investigate the morphology of bat ticks from Vietnam and to assess their taxonomic status in comparison with those collected in Europe. Ixodid bat ticks (two females and two nymphs) collected from the pomona leaf-nosed bat (Hipposideros pomona) (Hipposideridae) and intermediate horseshoe bat (Rhinolophus affinis) (Rhinolophidae) in Vietnam showed major morphological differences from European isolates of I. vespertilionis, including the shape of the scutum, the enclosure and shape of porose areas, the presence of a caudo-lateral collar-like ridge ventrally on the basis capituli, polytrich coxae with short setae, and grouped (non-linear) arrangement of anterior pit sensillae in Haller's organ. In this study the female and the nymph of an ixodid bat tick species from Vietnam are described for the first time. The genetic and morphological differences between I. vespertilionis Koch, 1844 and these bat ticks from Vietnam justify the status of the latter as a distinct species, Ixodes collaris Hornok n. sp.
Shemshad, Khadijeh; Rafinejad, Javad; Kamali, Karim; Piazak, Norayer; Sedaghat, Mohammad Mahdi; Shemshad, Masoomeh; Biglarian, Akbar; Nourolahi, Fathollah; Valad Beigi, Enshallah; Enayati, Ahmad Ali
This report presents the results of the first faunistic study of hard ticks in Qazvin province of Iran. The primary objective was to determine the species diversity and geographic distribution of hard ticks that parasitize domestic ruminants. Information about the abiotic preferences of these species has been provided. A total of 286 cattle, 1,053 goats, and 2,050 sheep were examined in 13 villages in 28 flocks distributed throughout the studied areas. Total direct body collections of ticks were made from each domestic ruminant. A total of 228 Ixodid specimens belonging to nine species in three different genera were recorded in the areas, including Boophilus annulatus (Say, 1821), Hyalomma anatolicum Koch, 1844, Hyalomma asiaticum (Schulze and Schlettke, 1929), Hyalomma detritum Schulze, 1919, Hyalomma dromedarii Koch, 1844, Hyalomma marginatum Koch 1844, Hyalomma schulzei Olenev, 1931, Rhipicephalus bursa Canestrini and Fanz, 1878 and Rhipicephalus sanguineus (Latreille, 1806). The most abundant species on sheep was R. sanguineus (46.92%), while B. annulatus (6.6%) found only on cattle. A finding of great significance was that R. sanguineus, the main vector of babesiosis, is firmly established throughout the counties. A further objective of the study was to compare the abundance of the major tick species on domestic ruminants. This was carried out at 19 sampling sites. The highest number of ticks was collected in July-August during the hot season.
Ferrolho, Joana; Antunes, Sandra; Sanches, Gustavo S; Couto, Joana; Évora, Patrícia M; Rosa, Catarina; André, Marcos R; Machado, Rosângela Z; Bechara, Gervásio H; Domingos, Ana
Rhipicephalus sanguineus sensu lato (s.l.) is a very common ectoparasite of domestic dogs able to transmit several pathogens of human and veterinary importance. Tick infestations and tick-borne diseases (TBDs) remain a serious and persistent problem, due to the lack of efficient control measures. It is therefore vital that novel approaches to control are pursued. Whilst vaccination is recognised as a potential control method to reduce tick infestation, no anti-R. sanguineus vaccine is available. Ticks depend on their blood meals to obtain nutrients and to achieve sexual maturity, which exposes them to vast amounts of iron. Although an essential molecule for several biological processes, its excess can lead to oxidative stress. Iron homeostasis is achieved with the help of iron-binding proteins called ferritins, among others, present in several tick tissues and developmental stages. These evolutionarily conserved proteins regulate iron homeostasis by storing and releasing iron in a controlled manner. In this study the R. sanguineus ferritin 1 gene was silenced through RNA interference (RNAi) in adult females exposed to an experimental infection with Ehrlichia canis. The purpose of this study was to assess the role of this protein in tick feeding, ovary development, oogenesis, and pathogen acquisition. Our data has shown that silencing ferritin 1 alters tick competence to normally engorge and causes morphologic and histochemical changes in the ovaries (OV) and oocytes. Furthermore, our data revealed that no E. canis DNA was found in either experimental group. Determining the function of molecules that act in key biological processes, such as blood digestion or reproduction, and that could be considered potential tick antigens will contribute towards the improvement of current control measures against these ectoparasites and the pathogens they vector.
Aléssio, Filipe Martins; Dantas-Torres, Filipe; Siqueira, Daniel Barreto; Lizée, Marie-Hélène; Marvulo, Maria Fernanda Vianna; Martins, Thiago Fernandes; Labruna, Marcelo Bahia; Silva, Jean Carlos Ramos; Mauffrey, Jean-François
We investigated the Amblyomma fuscum load on a pullulating wild rodent population and the environmental and biological factors influencing the tick load on the hosts. One hundred and three individuals of Thrichomys laurentius were caught in an Atlantic forest fragment in northeastern Brazil, as part of a longitudinal survey on ticks infesting non-volant small mammals. Ticks (n = 342) were found on 45 individuals and the overall mean intensity of infestation was 7.6 ticks per infested rodent. Ticks were highly aggregated in the host population and the negative binomial distribution model provides a statistically satisfactory fit. The aggregated distribution was influenced by sex and age of the host. The microhabitat preference by T. laurentius probably increases contact opportunities between hosts and aggregated infesting stages of the ticks and represents important clues about the habitat suitability for A. fuscum.
In a collaboration with Purdue University researchers, we sequenced a 143,606 base pair Rhipicephalus microplus BAC library clone that contained the coding region for acetylcholinesterase 1 (AChE1). Sequencing was by Sanger protocols and the final assembly resulted in 15 contigs of varying length, e...
Foley, Janet E; Hasty, Jeomhee M; Lane, Robert S
Cervids host multiple species of ixodid ticks, other ectoparasites, and a variety of rickettsiae. However, diagnostic test cross-reactivity has precluded understanding the specific role of deer in rickettsial ecology. In our survey of 128 Columbian black-tailed deer (Odocoileus hemionus columbianus (Richardson)) and their arthropod parasites from two northern Californian herds, combined with reports from the literature, we identified four distinct Anaplasma spp. and one Ehrlichia species. Two keds, Lipoptena depressa (Say) and Neolipoptena ferrisi Bequaert, and two ixodid ticks, Ixodes pacificus Cooley and Kohls and Dermacentor occidentalis Marx, were removed from deer. One D. occidentalis was PCR-positive for E. chaffeensis; because it was also PCR-positive for Anaplasma sp., this is an Anaplasma/Ehrlichia co-infection prevalence of 4.3%. 29% of L. depressa, 23% of D. occidentalis, and 14% of deer were PCR-positive for Anaplasma spp. DNA sequencing confirmed A. bovis and A. ovis infections in D. occidentalis, A. odocoilei in deer and keds, and Anaplasma phagocytophilum strain WI-1 in keds and deer. This is the first report of Anaplasma spp. in a North America deer ked, and begs the question whether L. depressa may be a competent vector of Anaplasma spp. or merely acquire such bacteria while feeding on rickettsemic deer. © 2016 The Society for Vector Ecology.
Lee, Xia; Hardy, Kristin; Johnson, Diep Hoang; Paskewitz, Susan M
As a result of the increasing incidence of Lyme disease and other tick-borne pathogens in Wisconsin, we assessed the distribution of adult blacklegged ticks through collections from hunter-killed deer in 2008 and 2009 and compared results with prior surveys beginning in 1981. Volunteers staffed 21 Wisconsin Department of Natural Resources registration stations in 21 counties in the eastern half of Wisconsin in 2008 and 10 stations in seven counties in northwestern Wisconsin in 2009. In total, 786 and 300 white-tailed deer (Odocoileus virginianus) were examined in 2008 and 2009, respectively. All but three stations in 2008 were positive for ticks and all stations in 2009 were positive for ticks. The three sites negative for ticks occurred within the eastern half of Wisconsin. The results indicate that range expansion of Ixodes scapularis (Say) is continuing and the risk of tick exposure is increasing, especially in the eastern one-third of the state.
Keirans, J E; Hutcheson, H J; Durden, L A; Klompen, J S
The blacklegged tick, Ixodes (Ixodes) scapularis Say, 1821, is redescribed, based on laboratory reared specimens originating in Bulloch County, Georgia. Information on distribution, host associations, morphological variation, and medical/veterinary importance is also presented. A great deal of recent work has focused on this species because it is the principal vector of the agent of Lyme disease (Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner) in eastern North America. Its distribution appears to be expanding, and includes the state of Florida in the southeastern United States north to the provinces of Nova Scotia and Prince Edward Island, Canada, west to North and South Dakota, United States, and south to the state of Coahuila, Mexico. Although I. scapularis feeds on at least 125 species of North American vertebrates (54 mammalian, 57 avian, and 14 lizard species), analysis of the U.S. National Tick Collection holdings show that white-tailed deer, Odocoileus virginianus (Zimmermann), cattle, Bos taurus L., dogs, Canis lupus L., and other medium-to-large sized mammals are important hosts for adults as are native mice and other small mammals, certain ground-frequenting birds, skinks, and glass lizards for nymphs and larvae. This tick is a polytypic species exhibiting north-south and east-west morphological clines. Analysis of variance and Student-Newman-Keuls multiple comparisons revealed significant interpopulational variation that is expressed most significantly in the nymphal stage. Nymphs from northern (Minnesota, Massachusetts, Maryland) populations had relatively larger basis capituli with shorter cornua (except Maryland) than southern (North Carolina, Georgia) populations. Midwestern populations (Minnesota, Missouri) differed from eastern populations (Massachusetts, Maryland, North Carolina, Georgia) in idiosomal characters (broader scuta, larger coxae III, and IV). In addition to Lyme disease, this tick is also a primary vector of the agent of human and rodent babesiosis, Babesia microti Franca. Under laboratory conditions it has transmitted the agents of deer babesiosis, Babesia odocoilei Emerson & Wright, tularemia, Francisella tularensis McCoy & Chapin, and anaplasmosis, Anaplasma marginale Theiler. Moreover, I. scapularis can reach pest proportions on livestock, and females can cause tick paralysis in dogs.
Poucher, K L; Hutcheson, H J; Keirans, J E; Durden, L A; Black, W C
A taxonomic key, based on restriction enzyme analysis of the second internal-transcribed spacer (ITS-2) in the nuclear ribosomal DNA gene, was developed for identification of 17 Ixodes tick species in the United States. This key includes: Ixodes affinis Neumann, Ixodes angustus Neumann, Ixodes baergi Cooley and Kohls, Ixodes brunneus Koch, Ixodes cookei Packard, Ixodes dentatus Marx, Ixodes jellisoni Cooley and Kohls, Ixodes kingi Bishopp, Ixodes minor Neumann, Ixodes muris Bishopp and Smith, Ixodes pacificus Cooley and Kohls, Ixodes scapularis Say, Ixodes sculpularis Neumann, I. spinipalpis Hadwen and Nuttall, Ixodes texanus Banks, Ixodes uriae White, and Ixodes woodi Bishopp. A 900-bp fragment of the ITS-2 was amplified using the polymerase chain reaction. This fragment was then digested with the restriction enzymes MspI and CfoI, and the digested fragments were size fractionated on a 2.5% high-resolution agarose gel. A dichotomous key was developed based on digested fragment sizes relative to a standard set of size markers. Little intraspecific variation in restriction fragment banding patterns was detected.
Rodríguez-Vivas, R I; Ojeda-Chi, M M; Rosado-Aguilar, J A; Trinidad-Martínez, I C; Torres-Acosta, J F J; Ticante-Perez, V; Castro-Marín, J M; Tapia-Moo, C A; Vázquez-Gómez, G
Rhipicephalus microplus is the most economically important cattle tick in the Mexican tropics. Wild ungulate species, including red deer (Cervus elaphus), are gaining popularity in diversified livestock ranching operations in Mexico. However, there is no information available on the susceptibility of red deer to infestation with the cattle tick, R. microplus, under hot, subhumid tropical conditions in Mexico. Biological data on R. microplus as an ectoparasite of cattle and red deer in a farm in the Mexican tropics are presented here. Ticks collected from red deer were identified as R. microplus (97 %) and Amblyomma cajennense (3 %), and tick species infesting cattle included R. microplus (95 %) and A. cajennense (5 %). Standard counts of R. microplus engorged females on red deer were 11 times higher than on cattle (428 ± 43 vs. 40 ± 18; p < 0.001). The reproductive efficiency index and larval hatching of R. microplus collected from cattle and red deer were similar (p > 0.05). Hemolymph samples of R. microplus collected from cattle were positive for Babesia spp. (10 %, 2/50) and all the samples from ticks infesting red deer were negative. Seventeen and ten percent of the blood samples from cattle and red deer were positive for Anaplasma marginale, respectively. The role of red deer as a host of R. microplus in Yucatan, Mexico and the importance of this host-parasite relationship relative to the epidemiology of R. microplus-borne diseases are discussed.
Estrada-Peña, Agustín; Estrada-Sánchez, Adrián; Estrada-Sánchez, David
Foci of tick species occur at large spatial scales. They are intrinsically difficult to detect because the effect of geographical factors affecting conceptual influence of climate gradients. Here we use a large dataset of occurrences of ticks in the Afrotropical region to outline the main associations of those tick species with the climate space. Using a principal components reduction of monthly temperature and rainfall values over the Afrotropical region, we describe and compare the climate spaces of ticks in a gridded climate space. The dendrogram of distances among taxa according to occurrences in the climate niche is used to draw functional groups, or clusters of species with similar occurrences in the climate space, as different from morphologically derived (taxonomical) groups. We aim to further define the drivers of species richness and endemism at such a grid as well as niche similarities (climate space overlap) among species. Groups of species, as defined from morphological traits alone, are uncorrelated with functional clusters. Taxonomically related species occur separately in the climate gradients. Species belonging to the same functional group share more niche among them than with species in other functional groups. However, niche equivalency is also low for species within the same taxonomic cluster. Thus, taxa evolving from the same lineage tend to maximize the occupancy of the climate space and avoid overlaps with other species of the same taxonomic group. Richness values are drawn across the gradient of seasonal variation of temperature, higher values observed in a portion of the climate space with low thermal seasonality. Richness and endemism values are weakly correlated with mean values of temperature and rainfall. The most parsimonious explanation for the different taxonomic groups that exhibit common patterns of climate space subdivision is that they have a shared biogeographic history acting over a group of ancestrally co-distributed organisms. PMID:22629349
Eisen, Rebecca J; Eisen, Lars; Beard, Charles B
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.
Barros-Battesti, Darci Moraes; Landulfo, Gabriel Alves; Luz, Hermes Ribeiro; Marcili, Arlei; Onofrio, Valeria Castilho; Famadas, Kátia Maria
Most argasid ticks from the Neotropical region are parasites of mammals and birds, with a few records from reptiles. Many species of the genus Ornithodoros are known only through larval descriptions, and their chaetotaxy and morphological characteristics have been used to separate the taxa. In the present study, we describe the larva and the nymph of first instar of a new species of the genus Ornithodoros that was collected from frogs of the species Thoropa miliaris. Larvae of Ornithodoros were collected from frogs of the species T. miliaris at waterfalls in the state of Rio de Janeiro, southeastern Brazil. The larval and nymphal description was based on optical and scanning electron microscopy. Molecular analysis using the argasid 16S rRNA sequences available in GenBank was also conducted. Ornithodoros faccinii sp. n. is closely related to Ornithodoros clarki Jones & Clifford, Ornithodoros marinkellei Kohls, Clifford & Jones, Ornithodoros capensis Neumann and Ornithodoros sawaii Kitaoka & Susuki. However, the larval morphology of the new species is unique. The mitochondrial 16S rDNA partial sequence of O. faccinii generated in the present study was deposited in GenBank under the number KP861242. The larvae collected from Thoropa miliaris are a new species, Ornithodoros faccinii n. sp. This is the first report of argasid ticks on frogs in Brazil, the second on frogs and the third on Amphibia in the Neotropical region.
Ginsberg, Howard; Lee, Chong; Volson, Barry; Dyer, Megan C.; LeBrun, Roger A.
The relationship between engorgement weight of female Ixodes scapularis Say and characteristics of offspring was studied using field-collected females fed on rabbits in the laboratory. The number of eggs laid was positively related to maternal engorgement weight in one trial, and larval size (estimated by scutal area) was positively related to maternal engorgement weight in the other. These results suggest a trade-off in number of eggs produced versus average size of offspring, possibly determined during late engorgement. The adults for the two trials were collected from different sites in southern Rhode Island and in different seasons (the fall adults were newly emerged, while the spring adults had presumably lived through the winter), so it is not clear whether these results reflect genetic differences or subtle environmental differences between trials. Percent egg hatch and average fat content of larvae were not related to female engorgement weight. We present a modified method to measure lipid content of pooled larval ticks.
Paskewitz, S M; Vandermause, M; Belongia, E A; Kazmierczak, J J
Four state parks located in Lyme disease endemic regions of Wisconsin were surveyed for the presence of Ixodes scapularis Say during May and June of 1998 by drag sampling along hiking trails. Nymphal abundance varied between parks, with the average number of nymphs encountered in 1 h ranging from 6.2 +/- 3.8-47.1 +/- 36.3 (mean +/- SD). Questing nymphs were tested for the presence of Borrelia burgdorferi by culture in BSK medium and 7-12% was found to be infected. The average risk of encountering an infected nymph (entomologic risk index) ranged from 0.5 to 5.2 infected nymphs per hour. The highest entomological risk index was recorded from a small island park in northwestern Wisconsin during the last week in May (8.0 infected nymphs per hour). These results indicate a lower risk for human Lyme disease exposure in Wisconsin state parks in comparison with highly endemic areas of the northeastern United States.
Guglielmone, A A; Estrada-Peña, A; Mangold, A J; Barros-Battesti, D M; Labruna, M B; Martins, J R; Venzal, J M; Arzua, M; Keirans, J E
DNA sequences of Amblyomma aureolatum (Pallas, 1772) and Amblyomma ovale Koch, 1844 were obtained to determine genetic differences between these tick species. Collections of these species are discussed in relation to distribution and hosts. Seven ticks collections (four from Brazil, one from Argentina, one from Uruguay and one from USA) house a total of 1272 A. aureolatum (224 males, 251 females, 223 nymphs and 574 larvae) and 1164 A. ovale (535 males, 556 females, 66 nymphs and 7 larvae). The length of the sequenced mitochondrial 16S rRNA gene fragment for A. aureolatum was 370bp and for A. ovale was 373bp. The DNA sequence analysis showed a 13.1% difference between the two species. Apart from one male A. ovale found on a toad, all adult ticks were found on mammals. The majority of adult specimens of both tick species were removed from Carnivora (96.1 and 84.3% of A. aureolatum and A. ovale, respectively), especially from dogs (53.1% of A. aureolatum, and 46.4% of A. ovale). Collections on wild Canidae were higher for A. aureolatum (23.3%) than for A. ovale (7.1%). On the other hand, collections of A. ovale adults on wild Felidae were higher (18.3%) than findings of A. aureolatum (9.2%). The contribution of other mammalian orders as hosts for adults of A. aureolatum and A. ovale was irrelevant, with the exception of Perissodactyla because Tapiridae contributed with 13.0% of the total number of A. ovale adults. Adults of both tick species have been found occasionally on domestic hosts (apart of the dog) and humans. Most immature stages of A. aureolatum were found on Passeriformes birds, while rodents and carnivores were the most common hosts for nymphs and larvae of A. ovale. A. aureolatum has been found restricted to the Neotropical region, covering the eastern area of South America from Uruguay to Surinam, including northeastern Argentina, eastern Paraguay, southeastern Brazil and French Guiana. A. ovale showed a distribution that covers the Neotropical region from central-northern Argentina throughout the Neotropics into the Nearctic region of Mexico with a few records from the USA, also with collection sites in Paraguay, Bolivia, most Brazilian states, Peru, Ecuador, French Guiana, Surinam, Guyana, Trinidad & Tobago, Venezuela, Colombia, Panama, Costa Rica, Nicaragua, Belize, Guatemala and several states of Mexico.
Ibrahim, M A; Ghazy, A H; Maharem, T; Khalil, M
Two forms of the nymphal thrombin inhibitors (NTI) 3.2 kDa and 14.9 kDa were purified by chromatography on CM-cellulose. Sephacryl S-300 and Sephadex G-50 columns and designated NTI- 1 and NTI-2 respectively. The NTI-2 turned out to be homogenous monomeric protein in both native-PAGE and denatured SDS-PAGE with M(r) value of 14.9 kDa approximately and its pI value ranged from 7.2 to 7.5. The NTI-1 and NTI-2 displayed anticoagulant activity since they prolonged both the activated partial thromboplastin time (APTT) and the prothrombin time (PT) of the camel plasma in a concentration-dependent manner. The potency of NTI-I toward thrombin was 5-fold higher than that toward FXa, while NTI-2 was 3-fold active toward FXa than thrombin. However, both of them did not inhibit any of the other examined proteases. The types of inhibition of thrombin by NTI-1 and NTI-2 were non-competitive and competitive with inhibition constants (Ki) values of 11.7 microM and 211 nM respectively. One binding site was deduced on thrombin for each inhibitor.
De Clercq, E M; Leta, S; Estrada-Peña, A; Madder, M; Adehan, S; Vanwambeke, S O
Rhipicephalus microplus is one of the most widely distributed and economically important ticks, transmitting Babesia bigemina, B. bovis and Anaplasma marginale. It was recently introduced to West Africa on live animals originating from Brazil. Knowing the precise environmental suitability for the tick would allow veterinary health officials to draft vector control strategies for different regions of the country. To test the performance of modelling algorithms and different sets of environmental explanatory variables, species distribution models for this tick species in Benin were developed using generalized linear models, linear discriminant analysis and random forests. The training data for these models were a dataset containing reported absence or presence in 104 farms, randomly selected across Benin. These farms were sampled at the end of the rainy season, which corresponds with an annual peak in tick abundance. Two environmental datasets for the country of Benin were compared: one based on interpolated climate data (WorldClim) and one based on remotely sensed images (MODIS). The pixel size for both environmental datasets was 1 km. Highly suitable areas occurred mainly along the warmer and humid coast extending northwards to central Benin. The northern hot and drier areas were found to be unsuitable. The models developed and tested on data from the entire country were generally found to perform well, having an AUC value greater than 0.92. Although statistically significant, only small differences in accuracy measures were found between the modelling algorithms, or between the environmental datasets. The resulting risk maps differed nonetheless. Models based on interpolated climate suggested gradual variations in habitat suitability, while those based on remotely sensed data indicated a sharper contrast between suitable and unsuitable areas, and a patchy distribution of the suitable areas. Remotely sensed data yielded more spatial detail in the predictions. When computing accuracy measures on a subset of data along the invasion front, the modelling technique Random Forest outperformed the other modelling approaches, and results with MODIS-derived variables were better than those using WorldClim data. The high environmental suitability for R. microplus in the southern half of Benin raises concern at the regional level for animal health, including its potential to substantially alter transmission risk of Babesia bovis. The northern part of Benin appeared overall of low environmental suitability. Continuous surveillance in the transition zone however remains relevant, in relation to important cattle movements in the region, and to the invasive character of R. microplus. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.
Gharbi, Mohamed; Hayouni, Mohamed Ettaïeb; Sassi, Limam; Dridi, Walid; Darghouth, Mohamed Aziz
Hyalomma scupense is a two-host tick infesting mainly cattle representing in North Africa the vector of tropical theileriosis (Theileria annulata infection), a major tick-borne disease affecting cattle. Any effective control programme of ticks requires a good knowledge of the biology of the target species. In the present study, three cattle farms in northeast Tunisia were surveyed during the activity seasons for adult and nymphs of Hyalomma scupense. Several indicators were studied, including chronological indicators, infestation prevalence, infestation intensity and feeding predilection sites of the ticks. The adult ticks were present from mid-June to late November. Nymphs were observed on animals from early September to late November. A large proportion of the ticks were attached in the posterior udder quarters: 41% and 64% of adult ticks and nymphs, respectively. The animals that were heavily infested by adult ticks were also heavily infested by nymphs. Moreover, 17% of adult ticks and 53% of nymphs were present on only 5% of cattle population. These data are important for the success of targeted acaricide application leading to a dramatic decrease of acaricide quantity needed for the treatment. When the preferential sites of attachment are known, the effectiveness of manual removal of ticks can be improved. The presence of highly infested animals is to be considered when any control programme is implemented, since these animals harbour a high proportion of the ticks. PMID:23547915
Arzua, Márcia; Navarro Da Silva, Mário Antonio; Famadas, Kátia Maria; Beati, Lorenza; Barros-Battesti, Darci Moraes
Between January 1999 and December 2000, 876 bird specimens were captured in three different ecological environments from the Reinhard Maack Park, Curitiba, State of Paraná, southern Brazil. A total of 142 birds (16.2%) were infested with Amblyomma aureolatum (Pallas 1772) (N=699) and/or Ixodes auritulus Neumann, 1904 (N=18) ticks. Questing A. aureolatum nymphs (N=2) and adults (N=5) were also collected from the soil and the vegetation. None of the I. auritulus were collected off-host. We collected only immatures of A. aureolatum on birds, but all life stages of I. auritulus. The latter species was collected on Turdus rufiventris and on Synallaxis ruficapilla, which is herein recognized as a host of I. auritulus for the first time. Moreover, this is also the first report of A. aureolatum infesting birds, and 16 different bird species were found infested. It was observed that larval infestation was positively correlated with the dry and cold season, while nymphal infestation was positively correlated with the warm and rainy season. Although only 2-years worth of data is provided, our results suggest the infestation of birds by ticks was significantly higher at the biotopes formed by forest at its first stage of regeneration 'capoeira' and the original Araucaria forest habitat 'mata' than the ecotone between forest and urban areas 'peripheral area'.
McIntosh, Douglas; Bezerra, Rodrigo Alves; Luz, Hermes Ribeiro; Faccini, João Luiz Horacio; Gaiotto, Fernanda Amato; Giné, Gastón Andrés Fernandez; Albuquerque, George Rego
Studies investigating rickettsial infections in ticks parasitizing wild animals in the Northeast region of Brazil have been confined to the detection of Rickettsia amblyommii in immature stages of Amblyomma longirostre collected from birds in the state of Bahia, and in immatures and females of Amblyomma auriculariumcollected from the striped hog-nosed skunk (Conepatus semistriatus) and armadillos (Euphractus sexcinctus) in the state of Pernambuco. The current study extends the distribution of R. amblyommii (strain Aranha), which was detected in A. longirostre collected from the thin-spined porcupine Chaetomys subspinosus and the hairy dwarf porcupine Coendou insidiosus. In addition, we report the first detection of Rickettsia bellii in adults of A. longirostre collected from C. insidiosus in the state of Bahia. PMID:26413074
Dolan, Marc C; Breuner, Nicole E; Hojgaard, Andrias; Boegler, Karen A; Hoxmeier, J Charles; Replogle, Adam J; Eisen, Lars
The recently recognized Lyme disease spirochete, Borrelia mayonii, has been detected in host-seeking Ixodes scapularis Say ticks and is associated with human disease in the Upper Midwest. Although experimentally shown to be vector competent, studies have been lacking to determine the duration of time from attachment of a single B. mayonii-infected I. scapularis nymph to transmission of spirochetes to a host. If B. mayonii spirochetes were found to be transmitted within the first 24 h after tick attachment, in contrast to Borrelia burgdorferi spirochetes (>24 h), then current recommendations for tick checks and prompt tick removal as a way to prevent transmission of Lyme disease spirochetes would need to be amended. We therefore conducted a study to determine the probability of transmission of B. mayonii spirochetes from single infected nymphal I. scapularis ticks to susceptible experimental mouse hosts at three time points postattachment (24, 48, and 72 h) and for a complete feed (>72-96 h). No evidence of infection with or exposure to B. mayonii occurred in mice that were fed upon by a single infected nymph for 24 or 48 h. The probability of transmission by a single infected nymphal tick was 31% after 72 h of attachment and 57% for a complete feed. In addition, due to unintended simultaneous feeding upon some mice by two B. mayonii-infected nymphs, we recorded a single occasion in which feeding for 48 h by two infected nymphs resulted in transmission and viable infection in the mouse. We conclude that the duration of attachment of a single infected nymphal I. scapularis tick required for transmission of B. mayonii appears to be similar to that for B. burgdorferi: transmission is minimal for the first 24 h of attachment, rare up to 48 h, but then increases distinctly by 72 h postattachment. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.
Muñoz-Leal, Sebastián; Tarragona, Evelina L; Martins, Thiago F; Martín, Claudia M; Burgos-Gallardo, Freddy; Nava, Santiago; Labruna, Marcelo B; González-Acuña, Daniel
Adults of Amblyomma parvitarsum are common ectoparasites of South American camelids of the genera Lama and Vicugna, occuring in highlands of Argentina, Bolivia, Chile, Peru and also in Argentinean Patagonia. Whereas larval stages of this tick are known to feed on small lizards, host records for the nymphal instar have remained unreported. Supported by morphological and molecular analyses, herein we report A. parvitarsum nymphs parasitizing two Liolaemus species (Reptilia: Squamata) in the Andean Plateau of Argentina and Chile. Additionally, by a PCR screening targetting gltA and ompA genes, DNA of Rickettsia was detected in one of the collected nymphs. Obtained sequences of this agent were identical to a recent Rickettsia sp. described infecting adults of this tick species in Chile and Argentina.
Labruna, Marcelo B; Gerardi, Monize; Krawczak, Felipe S; Moraes-Filho, Jonas
Recent studies have shown that the taxon Rhipicephalus sanguineus sensu lato (s.l.) is represented in Latin America by two distinct species, designated as 'tropical species' (distributed from Mexico to Brazil) and 'temperate species' (restricted to the southern cone of South America). Since both tropical and temperate species of R. sanguineus s.l. are parasites primarily of domestic dogs, the reasons for their distinct geographical distribution in South America could be related to particular requirements of abiotic conditions for off-host development. With the purpose to test this hypothesis, this study evaluated the off-host developmental stages (eggs, engorged larvae, nymphs and females) of both tick species simultaneously inside incubators with temperature and photoperiod regimens that simulated the summer and winter conditions of tropical Brazil (where the 'tropical species' occurs) and temperate Brazil (where the 'temperate species' occurs). Results showed that the temperate species had significantly higher survival rates than the tropical species, when engorged ticks (larvae, nymphs and females) and eggs were incubated at lower temperatures simulating winter seasons of many parts of the southern cone of South America, where the temperate species is known to occur. These results suggest that the absence of established populations of the tropical species in temperate areas of South America is related to the low overwinter capacity of the tropical species in those areas. Regarding the temperate species, unfed adults that molted from nymphs under summer conditions of either tropical or temperate Brazil remained dormant, at the state of behavioral diapause for at least 20 weeks. Contrastingly, when engorged nymphs of the temperate species were held at winter conditions for at least 3 months, and then transferred to summer conditions to complete molting, no diapause was observed in adult ticks. These results were corroborated by infestation trials, which showed that diapausing adult ticks took more days to attach to rabbits, and did in lesser numbers, when compared to nondiapausing adult ticks. Contextualization of our results in the current literature suggests that absence of established populations of the temperate species in tropical Brazil is linked to the fact that adult ticks would become inactive (diapause) right after molting from nymphs at any period of the year. On the other hand, absence of established populations of the tropical species in temperate Brazil is linked to the fact that this tick species would not enter diapause, and therefore, could not synchronize its life-cycle to avoid the lethal effects of a more severe winter on its developmental stages. Indeed, such assumptions should be corroborated by additional studies testing different populations of the tropical and temperate species, including more studies under natural conditions.
Uspensky, I; Rubina, M
A phenomenon of host substitution by the taiga tick (Ixodes persulcatus) larvae was observed by the authors in the western part of the Soviet Far East. In the mountain forests where the highest abundance of I. persulcatus was found, larvae usually fed on small mammals (primarily on Clethrionomys rufocanus, C. rutilus and Apodemus speciosus). Numerous larvae were found, however, on the mountain hare (Lepus timidus) in the years of deep depression in the abundance of small mammals. The host substitution is considered as one of the mechanisms stabilizing the abundance of I. persulcatus adults.
Patterns of attacking hosts by two closely related species of ixodid ticks (Ixodes persulcatus and I. ricinus) were compared in parallel field tests. The ability of active unfed adults of both sexes to adhere to a flannel flag dragged over grass vegetation and to remain on the flag during this process were estimated. The tests were conducted under two temperature conditions, 6-10 degrees C and 17-22 degrees C. In all test versions, adults of I. persulcatus were more successful both in adhering to the flag and in remaining on it. There were no consistent differences between males and females of the same species. The results demonstrated a differing ability of successful attack in both tick species. This ability is a complex derivative of the tick activity and aggressiveness. An attempt is made to analyse the latter phenomenon, which is considered as a general one for all bloodsucking arthropods. The aggressiveness of arthropods should be taken into account as one of the leading factors influencing the sampling results.
Uspensky, Igor; Ioffe-Uspensky, Inna
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.
Martin, P A; Schmidtmann, E T
The spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Benner is transmitted by Ixodes scapularis Say, a vector of Lyme disease. As a 1st step into investigating the possibility of biocontrol of the tick, we identified the microbiota associated with the ticks. We collected, identified, and determined the sex of ticks from foliage and deer. Seventy-three initial bacterial isolates were recovered from 43 ticks (27 adults and 16 nymphs). The bacteria isolated from nymphs were qualitatively different (mainly gram-negative cocci) from the bacteria isolated from adult ticks (gram-negative and gram-positive rods). To determine long-term viability, these isolates were stored for 6 mo under laboratory conditions. After storage, 63 surviving bacterial isolates were characterized using the Biology System of identification by substrate utilization. Forty-four isolates were identified to the species level. Our characterization efforts focused on the 40 spore-forming bacteria, which could prove useful in the biocontrol of ticks. Eleven species of Bacillus were identified. Bacillus thuringiensis-B. cereus was the predominant species group isolated. Six isolates from this group formed crystals.
Fernández-Salas, A; Alonso-Díaz, M A; Acosta-Rodríguez, R; Torres-Acosta, J F J; Sandoval-Castro, C A; Rodríguez-Vivas, R I
The objectives of this study were to evaluate the in vitro acaricidal effects of lyophilized extracts of four tannin rich plants (Acacia pennatula, Piscidia piscipula, Leucaena leucocephala and Lysiloma latisiliquum) against diverse stages of Rhipicephalus (Boophilus) microplus, and to asses whether tannins were involved in the acaricidal effect using polyethylene glycol (PEG) to block tannins. Larval immersion (LIT) and adult immersion (AIT) tests were used to evaluate the acaricidal effect of each of the lyophilized extracts against larval and adult stages of R. microplus respectively. Larvae and adult ticks were exposed to increasing concentrations of each plant extract (0, 1200, 2400, 4800, 9600 and 19,200 μg ml(-1)) for 10 min. Larval mortality was recorded at 48 h post-incubation. Adult mortality was recorded daily over 14 days, at which point their reproductive efficiency was evaluated. PEG was added to the extracts to verify whether tannins were involved in the acaricidal effect. The effect on egg laying inhibition and larval mortality was analyzed using the GLM procedure in SAS. A Kruskal-Wallis test was used to assess the effect of PEG on LIT results. Calculation of the lethal concentration 50 (LC50) was performed using a probit analysis. All extracts reduced the viability of R. microplus larval stages (P<0.001), and viability was restored with the addition of PEG suggesting an important role of tannins in the acaricidal effect (P<0.001). The LC50 values of L. latisiliquum and P. piscipula plant extracts were 6.402 and 2.466 μg ml(-1). None of the tannin-rich plant extracts affected adult mortality (P>0.05). Lysiloma latisiliquum extract inhibited egg hatching of R. microplus (P<0.01). Tannin-rich plant extracts from A. pennatula, P. piscipula, L. leucocephala and L. latisiliquum showed potential acaricidal activity. Further in vivo studies are needed to confirm this finding.
Camargo-Mathias, Maria Izabel; Pereira, Natalia Rubio Claret; da Silva Reis, Camila; de Almeida, Cristiane Regina; Dos Santos Mendes, Douglas Rodrigo; de Araújo, Giselle Bezerra; Postali, Lays; Figueroa, Tober; Ferreira, Allan Roberto Fernandes; Santos, Juan Parente; de Oliveira, Patrícia Rosa
The cosmopolitan species Rhipicephalus sanguineus s.l. is one of the most widely distributed ticks all over the world. These ectoparasites are vectors of several pathogens and cause significant direct damage to their hosts. The biological success of these ectoparasites has been attributed to their ovaries and salivary glands, organs that ensure their survival in various environmental conditions. The importance of the ovaries in ticks is that, after mating, the individuals are able to lay approximately three thousand eggs. The present study had the objective to demonstrate the effects of deltamethrin obtained from the product Butox P CE 25(®) (MSD Saúde Animal, São Paulo, Brazil) on the ovarian development of R. sanguineus s.l. females. The chemical was tested in the concentrations of 25, 50, 100 and 200 ppm (respectively 80, 40, 20 and 10 times lower than the recommended by the manufacturer). Through the application of histological techniques and HE staining, the results showed that the deltamethrin was potentially able to modify the morphophysiology of the oocytes in all developmental stages, interfering in the vitellogenesis, causing intense vacuolation, cytoplasmic disorganization, and alterations in the chorion secretion. In addition, the chemical affected the germ vesicle of some oocytes, causing damages and hypertrophy, fragmenting the chromatin and forming bodies strongly stained by hematoxylin. Therefore, this study confirmed that the deltamethrin had an important action on the reproductive system of the R. sanguineus s.l. females, causing the precocious structural disorganization of the germ cells, consequently preventing the generation of new individuals.
Tajeri, S; Razmi, G R
Hard ticks have great importance because of blood feeding and transmitting dangerous human and animal diseases. Each year, they cause a lot of economical damage to the livestock industry. Control of ticks and tick-borne diseases is a major priority in most parts of the world and many studies have been done in this field. We know that studying haemoparasites and assessing the effect of different compounds on ticks requires a lot of money, support and sometimes it is time consuming. Considering all of these problems, today, in some research laboratories throughout the world, artificial in vitro feeding of ticks has become common. Development and application of such methods provide a cheap and accessible background for investigating haemoparasitic diseases under controlled conditions. For the first time we report successful in vitro feeding of two important ixodid ticks of the genus Hyalomma. Copyright © 2011 Elsevier B.V. All rights reserved.
Singh, Nirbhay Kumar; Singh, Harkirat; Jyoti; Prerna, Mranalini; Rath, Shitanshu S
The larval immersion test (LIT) was used on the progenies of Rhipicephalus (Boophilus) microplus collected from four districts of the Punjab state, India to test the resistance to ivermectin. The regression graphs of probit mortality of larval ticks plotted against log values of increasing concentrations of ivermectin were utilized for the determination of slope of mortality, lethal concentration for 50%(LC50), 95%(LC95), resistance ratios (RR50, RR95) and the resistance levels (RL). Values of the coefficient of determination (R(2)) for LIT ranged from 0.900 to 0.978, and the RR50 and RR95 values against ivermectin ranged from 2.97 to 8.85 and 2.42 to 8.47, respectively, indicating resistance status in all field isolates. On the basis of RR values, three field isolates (BAT, GUR, HOS) showed level II, whereas PTK isolate showed presence of level I resistance status against ivermectin. This appears to be the first report of ivermectin resistance in R. (B.) microplus from Punjab, India.
Keskin, Adem; Erciyas-Yavuz, Kiraz
Ticks are mandatory blood-feeding ectoparasites of mammals, birds, reptiles, and even amphibians. Turkey has a rich bird fauna and is located on the main migration route for many birds. However, information on ticks infesting birds is very limited. In the present study, we aimed to determine ticks infesting birds in Kızılırmak Delta, Turkey. In 2014 autumn bird migration season, a total of 7,452 birds belonging to 79 species, 52 genera, 35 families, and 14 orders were examined for tick infestation. In total, 287 (234 larvae, 47 nymphs, 6♀) ticks were collected from 54 passerine birds (prevalence = 0.72%) belonging to 12 species. Ticks were identified as Amblyomma sp., Dermacentor marginatus (Sulzer), Haemaphysalis concinna Koch, Haemaphysalis punctata Canestrini and Fanzago, Hyalomma sp., Ixodes frontalis (Panzer), and Ixodes ricinus (L). The most common tick species were I. frontalis (223 larvae, 23 nymphs, 6♀) followed by I. ricinus (3 larvae, 12 nymphs) and H. concinna (4 larvae, 6 nymphs). Based on our results, it can be said that Erithacus rubecula (L.) is the main host of immature I. frontalis, whereas Turdus merula L. is the most important carrier of immature stages of some ticks in Kızılırmak Delta, Turkey. To the best of our knowledge, most of the tick-host associations found in this study have never been documented in the literature. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Sun, Ming; Ren, Qiaoyun; Guan, Guiquan; Li, Yufeng; Han, Xueqing; Ma, Chao; Yin, Hong; Luo, Jianxun
Owing to the need to combat the spread of acaricide-resistant ticks, the development of long-term biological control has become a hot topic for tick control. In this study, we investigated the pathogenicity of three Beauveria bassiana isolates on the engorged female Rhipicephalus (Boophilus) microplus ticks using different conidial concentrations. The results showed that B. bassiana B.bAT17 was highly pathogenic against engorged R. (B.) microplus females, resulting in lethal time (LT50 and LT90) of 7.14 and 9.33 days at a concentration of 10(9)conidia/ml. R. (B.) microplus females treated with B. bassiana B.bAT17 significantly reduced the amount of ovipositioning; and most ticks died before they could begin to oviposit. Proteases and chitinases were analyzed in order to establish a screening method for identification of high virulent strains. This study has confirmed the significant pathogenic effect of entomopathogenic fungi against engorged R. (B.) microplus females in China, and further studies on the efficiency of the fungus against ticks in the field are required.
Barbosa, Carolina da Silva; Borges, Ligia Miranda Ferreira; Nicácio, José; Alves, Reginaldo Dias; Miguita, Carlos Henrique; Violante, Ivana Maria Póvoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Garcez, Fernanda Rodrigues
A total of 73 ethanol extracts from different anatomical parts of 44 plant species belonging to 24 families, native to the Mid-Western region of Brazil, were assessed in vitro for their effect on the reproductive cycle of engorged females of the cattle tick Rhipicephalus (Boophilus) microplus, using the adult immersion test. All extracts were evaluated at the concentration of 0.2 % and, among the extracts tested, the one obtained from the fruits of Guarea kunthiana (Meliaceae) proved to be highly efficacious, showing 99.1 % of product effectiveness. Extracts from other three species were shown to be moderately active, namely Nymphaea amazonum trunk (Nymphaeaceae) [51.7 %], Strychnos pseudoquina trunk (Loganiaceae) [48 %] [corrected] and Ocotea lancifolia leaves (Lauraceae) [34.5 %], while the remaining extracts were shown to be weakly active or inactive. This is the first report on the bioactivity of these species on egg production by engorged females of R. microplus.
Silva, Wilson Castro; Martins, João Ricardo de Souza; de Souza, Hellen Emília Menezes; Heinzen, Horacio; Cesio, Maria Verônica; Mato, Mauricio; Albrecht, Francine; de Azevedo, João Lúcio; de Barros, Neiva Monteiro
The mortality of 14-21-day-old Rhipicephalus (Boophilus) microplus larvae, and the mortality and fertility of groups of engorged adult females exposed to different concentrations of hexane, ethyl acetate and ethanol extracts of spiked pepper (Piper aduncum) were evaluated, using a completely randomized design with five treatment groups, two control groups, and two replicates for the larvae and five replicates for the adult females. Similar methodology was used to investigate the toxicity of the essential oil hydro-distillate (94.84% dillapiole) obtained from the P. aduncum crude hexane extract. The LC(50) of the hexane extract was 9.30 mg ml(-1) for larvae and the reproduction reduction ranged from 12.48% to 54.22%, while 0.1mg/ml(-1) of the essential oil induced 100% mortality in larvae. Literature reports on natural products active against R. microplus were listed and compared with the results presented here. These results indicate that P. aduncum extracts, and particularly its essential oil, are potential alternative control agents for R. microplus.
Anderson, Jennifer M; Sonenshine, Daniel E; Valenzuela, Jesus G
Background Ticks are obligate blood feeders. The midgut is the first major region of the body where blood and microbes ingested with the blood meal come in contact with the tick's internal tissues. Little is known about protein expression in the digestive tract of ticks. In this study, for analysis of global gene expression during tick attachment and feeding, we generated and sequenced 1,679 random transcripts (ESTs) from cDNA libraries from the midguts of female ticks at varying stages of feeding. Results Sequence analysis of the 1,679 ESTs resulted in the identification of 835 distinct transcripts, from these, a total of 82 transcripts were identified as proteins putatively directly involved in blood meal digestion, including enzymes involved in oxidative stress reduction/antimicrobial activity/detoxification, peptidase inhibitors, protein digestion (cysteine-, aspartic-, serine-, and metallo-peptidases), cell, protein and lipid binding including mucins and iron/heme metabolism and transport. A lectin-like protein with a high match to lectins in other tick species, allergen-like proteins and surface antigens important in pathogen recognition and/or antimicrobial activity were also found. Furthermore, midguts collected from the 6-day-fed ticks expressed twice as many transcripts involved in bloodmeal processing as midguts from unfed/2-day-fed ticks. Conclusion This tissue-specific transcriptome analysis provides an opportunity to examine the global expression of transcripts in the tick midgut and to compare the gut response to host attachment versus blood feeding and digestion. In contrast to those in salivary glands of other Ixodid ticks, most proteins in the D. variabilis midgut cDNA library were intracellular. Of the total ESTs associated with a function, an unusually large number of transcripts were associated with peptidases, cell, lipid and protein binding, and oxidative stress or detoxification. Presumably, this is consistent with their role in intracellular processing of the blood meal and response to microbial infections. The presence of many proteins with similar functions is consistent with the hypothesis that gene duplication contributed to the successful adaptation of ticks to hematophagy. Furthermore, these transcripts may be useful to scientists investigating the role of the tick midgut in blood-meal digestion, antimicrobial activity or the transmission of tick-borne pathogens. PMID:19021911
Rot, A; Gindin, G; Ment, D; Mishoutchenko, A; Glazer, I; Samish, M
Ticks are obligatory blood-sucking arthropods. Their life cycle includes a relatively short period of feeding on a vertebrate host and a long off-host period spent in the upper layer of the soil. Entomopathogenic fungi are known to be highly effective tick pathogens and the on-host application of these fungi may be a promising economic approach for tick control. In this study, we evaluated the tick control provided by spraying Metarhizium brunneum onto the tick's vertebrate host, specifically gerbils (Meriones tristrami) and rabbits (Oryctolagus cuniculus). The efficacy of the fungal treatment was not limited to a direct effect on the mortality of feeding ticks, but continued during molting (off host) and, in the case of female ticks, the treatment reduced the production of eggs and their hatching rate. The direct control of the on-host stages was relatively low (from 19 to 38%); whereas the effects of the applied fungus on subsequent tick development reduced the yield of the following engorged stages up to 30-63%. Engorged females that dropped from rabbits sprayed with M. brunneum laid 21.5% fewer eggs than the control females. Moreover, these ticks transmitted conidia by contact to the eggs which they laid, resulting a 3-fold reduction in the rate of hatching relative to the control. Based on theoretical cumulative calculations, these results suggest that if the progeny of each unfed stage feed on fungus-sprayed hosts, there will be a 92% reduction in the tick population within one generation. Two spray formulations, one based on mineral oil and another based on a starch-sucrose mixture, significantly enhanced on-host tick control, in comparison with an unformulated conidial suspension. The reduction in the number of nymphs that fed on the treated host and later developed into unfed adults was 54.9% for unformulated conidia, 70.4% for the oil formulation and 86.4% for the starch-sucrose formulation. Increasing the environmental humidity around the gerbils while the ticks fed on them to 90% RH significantly improved the control of the on-host developmental stages, reducing the number of engorged ticks that dropped from fungus-sprayed gerbils 3-fold in comparison with the same animals kept at 30-60% RH. There was no difference between the efficacy of the observed tick control at an ambient temperature of 21°C and that observed at 28°C. Copyright © 2012 Elsevier B.V. All rights reserved.
Fakoorziba, Mohammad Reza; Naddaf-Sani, Ali Asghar; Moemenbellah-Fard, Mohammad Djaefar; Azizi, Kourosh; Ahmadnia, Sara; Chinikar, Sadegh
Crimean-Congo haemorrhagic fever (CCHF) is a potentially fatal systemic viral disease in many parts of the world, including Iran. The nationwide incidence of human CCHF in endemic areas was 870 confirmed cases with 126 deaths (case fatality rate, CFR = 17.6 %) in the decade leading to 2012. The detection of the CCHF virus (CCHFV) genome in tick vectors is of fundamental importance for identifying these ticks as potential reservoirs of CCHFV infection. From May to October 2013, following detection of four new clinical cases resulting in two deaths in the city of Mashhad (northeast Iran), hard ticks were recovered from infested livestock in 40 villages in Khorasan-Razavi province and examined by the microscopic method for species identification. About a quarter of the ticks were then subjected to reverse-transcription polymerase chain reaction (RT-PCR) to detect the CCHFV genome. The PCR products were then sequenced, and their phylogenetic lineages were determined. A total of 407 hard ticks were captured, representing seven different species in two distinct genera. Members of the genus Hyalomma were widely distributed in all but two of the villages studied, and this was also the most frequent (83.3 %) tick genus. Of 105 adult ticks subjected to RT-PCR, four (3.8 %) ticks were found positive for the CCHFV genome. One brown ear tick, Rhipicephalus appendiculatus, was found to be naturally infected for the first time anywhere in the world. Ticks of Hyalomma asiaticum, Hyalomma marginatum, and Rhipicephalus turanicus were also found to be naturally infected with CCHFV. CCHFV found in these four different tick species were clustered in the same lineage with the Matin and SR3 strains from Pakistan and some other strains from Iran, indicating that these tick species were naturally infected with genetically closely related CCHFV in the region. The presence of CCHFV infection in four different hard tick species was confirmed using RT-PCR in northeast Iran. Part of this infection was attributed to Rh. appendiculatus, which is thus a potential new natural vector of CCHFV in Iran. It is also confirmed by phylogenetic analysis that CCHFV in this region is genetically closely related, even in the different tick species.
de Oliveira, Patrícia Rosa; Calligaris, Izabela Braggião; Roma, Gislaine Cristina; Bechara, Gervásio Henrique; Camargo-Mathias, Maria Izabel
The present study demonstrated the effects of the arthropod growth regulator, fluazuron (Acatak®), in the formation of the integument and digestive processes of Rhipicephalus sanguineus nymphs fed on rabbits treated with different doses of this chemical acaricide. For this, three different doses of fluazuron (20, 40, or 80 mg/kg) were applied "pour on" to the hosts (groups II, III, and IV), as well as distilled water to the control group. On the first day after treatment (24 h), the hosts were artificially infested with R. sanguineus nymphs. After full engorgement (7 days), the nymphs were removed, placed on labeled Petri dishes, and kept in biochemical oxygen demand incubator for 7 days. The engorged nymphs were then taken for morphological, histochemical, and histological analyses. The results showed the occurrence of cytological, morphohistological, and histochemical alterations in the integument and midgut of nymphs from all the different treated groups. These alterations occurred at cuticular level in the subdivisions of the cuticle, related to the size of the digestive cells, amount of accumulated blood elements, and digestive residues, as well as the presence of vacuoles in the cytoplasm of the digestive cells. Thus, this study demonstrated that fluazuron acts on the integument and midgut cells of R. sanguineus nymphs fed on treated rabbits and pointed out the possibility of the use of this chemical-which is more specific, less toxic, and less harmful to the environment and nontarget organisms-in the control of R. sanguineus, at least in the nymphal stage of its biological cycle.
Labruna, Marcelo B; Keirans, James E; Camargo, Luis Marcelo A; Ribeiro, Alberto F; Soares, Rodrigo M; Camargo, Erney P
In 2000, we initiated an investigation on the tick fauna of Rondônia State, where we collected many specimens of Amblyomma scalpturatum Neumann, 1906 and Amblyomma incisum Neumann, 1906. In addition, we also collected a third group of ticks that were morphologically closely related to those 2 species, but sufficiently different to be considered a distinct species; members of this group were subsequently identified as Amblyomma latepunctatum Tonelli-Rondelli, 1939, through comparison with the type specimens of this taxon. Herein, we redescribe both sexes of A. scalpturatum and A. incisum, the female of A. latepunctatum, and provide the first description of the male of this latter species. Molecular analysis of the second internal transcribed spacer (ITS2) from rDNA of specimens of the 3 species supports morphological results. Examination of both A. scalpturatum and A. incisum deposited in different tick collections revealed that A. latepunctatum appeared relatively frequently in the vials believed to contain specimens of A. incisum or A. scalpturatum. Before this study, A. latepunctatum was considered a synonym of A. scalpturatum. Herein, we provide morphological and molecular evidence to validate the species A. latepunctatum. The South American tapir (Tapirus terrestris) seems to be the primary host for the adult stage of A. latepunctatum, A. scalpturatum, and A. incisum.
Valente, Paula Pimentel; Amorim, Juliana Mendes; Castilho, Rachel Oliveira; Leite, Romário Cerqueira; Ribeiro, Múcio Flávio Barbosa
The tick Rhipicephalus microplus causes significant losses in livestock cattle and has developed increasing resistance to the primary acaricides that are used to treat these infections. The objective of this study was to identify new biomolecules or isolated substances showing acaricidal activity from plants. Larval packet tests were conducted to evaluate the effects of 11 species of plants and three isolated substances (betulinic acid, eugenol, and nerolidol) on R. microplus. An adult female immersion test was performed with the substance that showed the highest larvicidal activity, which was evaluated for inhibition of reproduction. Tests using Licania tomentosa, Hymenaea stigonocarpa, Hymenaea courbaril, Stryphnodendron obovatum, Jacaranda cuspidifolia, Jacaranda ulei, Struthanthus polyrhizus, Chrysobalanus icaco, Vernonia phosphorea, Duguetia furfuracea, and Simarouba versicolor extracts as well as the isolated substance betulinic acid indicated lower acaricidal effects on R. microplus larvae. The extract displaying the best larvicidal activity was the ethanolic extract from L. tomentosa at a concentration of 60%, resulting in a mortality rate of 40.3%. However, nerolidol and eugenol showed larvicidal activity, which was highest for eugenol. Nerolidol caused a 96.5% mortality rate in the R. microplus larvae at a high concentration of 30%, and eugenol caused 100% mortality at a concentration of 0.3%. In the adult immersion test, 5% eugenol was identified as a good biomolecule for controlling R. microplus, as demonstrated by its high acaricidal activity and inhibition of oviposition.
Allan, S A; Simmons, L A; Burridge, M J
The tortoise tick Amblyomma marmoreum Koch was found to be established on a reptile facility in central Florida. Over a 5-mo period, 443 ticks were collected from tortoises, dogs, and vegetation. Collections from hosts were primarily from 3 species of exotic tortoises, including leopard tortoises, Aldabra tortoises, and yellow-footed tortoises. The total numbers of ticks present, the presence of all life stages, and the slow development of this species indicate that this is not a recent infestation. The source of the infestation is unknown because no tortoises were imported or moved onto this premise within the previous year. The propensity of this tick to feed on mammals and reptiles as immatures, its status as an experimental heartwater vector, and potential for further accidental introductions to the United States elicit concern toward the more widespread establishment of this species.
Fouche, Gerda; Ramafuthula, Mary; Maselela, Vusi; Mokoena, Moses; Senabe, Jeremiah; Leboho, Tlabo; Sakong, Bellonah M; Adenubi, Olubukola T; Eloff, Jacobus N; Wellington, Kevin W
The African blue tick, Rhipicephalus (Boophilus) decoloratus, is a common tick species found in South Africa and affects cattle production as well as vectoring pathogens in regions of Africa and Asia. In an attempt to develop a non-toxic, lower cost and environmentally friendly tick control method, twenty-six plant extracts were prepared from thirteen plant species using 99.5% acetone and 99% ethanol. The adapted Shaw Larval Immersion Test (SLIT) was used to test the efficacy of the extracts. A 1% solution of each of the plant extracts was prepared for efficacy testing and the ethanol extracts were found to have better acaricidal activity than the acetone extracts. The ethanol extract from the leaves and flowers of Calpurnia aurea had the best activity [corrected mortality (CM)=82.9%] which was followed by the stem extract of Cissus quadrangularis (CM=80.4%). The plant species were screened against Vero cells and were found to have low toxicity. From this study it is apparent that there is potential for the development of botanicals as natural acaricides against R. (B.) decoloratus.
Osman, Ilham M; Mohammed, A S; Abdalla, A B
Laboratory test were carried out on eggs, larvae, nymphs and adults of Hyalomma anatolicum to determine the acaricidal activities of petroleum ether (PE) and crude ethanolic extracts (EE) from the leaves of Guiera senegalensis J.F. Gmel. (Combrataceae) using immersion method. Stock solutions, of 300 mg/ml (30%) of the each two extract, were prepared. Six two-fold serial dilutions each with three replicates were used. Both extracts, at the highest concentration 150 mg/ml (15%), induced 100% failure of hatching of the treated eggs. The concentrations of PE and EE that induced 50% inhibition of the hatchability (IC50) were 1.71 and 0.508%, respectively. In the larval immersion test (LIT), EE at 15% concentration caused complete mortality while the same concentration of PE resulted in 96% mortality. The mortalities increased with concentrations. There was a correlation between the mortalities and increased concentrations, the values of the linear correlation coefficient (r) for PE and EE were 0.93 and 0.79, and The LC50 and LC99 were 2.08 and 14.09, and 0.787 and 11.054, respectively. At the concentrations of 3.75%, 7.5% and 15%, PE inhibited the molting of the nymphs by 40, 55 and 65%, respectively, while EE induced 46.49, 64.3 and 71.4% inhibition, respectively. The effectiveness of the treatment against unfed adult females was assessed by measuring the feeding performance and egg production using adult immersion test (AIT). Although, there was no mortality in unfed adults, PE and EE inhibited feeding and egg-laying of the survived females by 35-100% and 6.16-100%, respectively. Our results indicated that G. senegalensis is a promising biocontrol candidate as an acaricidal agent against H. anatolicum.
Rosado-Aguilar, J A; Aguilar-Caballero, A; Rodriguez-Vivas, R I; Borges-Argaez, R; Garcia-Vazquez, Z; Mendez-Gonzalez, M
The acaricidal activity of crude extracts and fractions from stems and leaves of Petiveria alliacea (Phytolaccaceae) was carried out on larvae and adults of the cattle tick Rhipicephalus (Boophilus) microplus using the larval immersion test (LIT) and adult immersion test (AIT), respectively. Methanolic extracts of stems and leaves of P. alliacea showed 100% mortality on the LIT bioassay. On the other hand, methanolic extracts of leaves and stem on the AIT test showed 26% and 86% of mortality, respectively, egg laying inhibition of 40% and 91%, respectively and hatchability inhibition of 26% and 17%, respectively. Purification of the active stem methanolic extract showed that the activity was present in the n-hexane non-polar fraction. Bioassay-guided purification of the n-hexane fraction produced 10 semi-purified fractions; fraction B had the highest activity against tick larvae (100% mortality). Gas chromatography-mass spectrometry demonstrated that the chemical composition of the active fraction B samples were mainly composed of benzyltrisulfide (BTS) and benzyldisulfide (BDS). These metabolites might be responsible for the acaricidal activity of stem extract of P. alliacea. However, further experiments to evaluate the acaricidal activity of BTS and BDS on larvae and adults of R. (B.) microplus are needed. Our results showed that P. alliacea is a promising biocontrol candidate as acaricide against R. (B.) microplus resistant strains.
Daemon, Erik; Monteiro, Caio Márcio Oliveira; Maturano, Ralph; Senra, Tatiane Oliveira Souza; Calmon, Fernanda; Faza, Aline; de Azevedo Prata, Márcia Cristina; Georgopoulos, Stéfanos Leite; de Oliveira, Luiz Fernando Cappa
The acaricidal activity of three thymol formulations was investigated at five concentrations (1.25, 2.5, 5.0, 7.5, and 10.0 mg/ml) on Rhipicephalus microplus larvae, and the behavior of its solubility in these formulations was analyzed. The thymol was dissolved in distilled water plus 1 % dimethylsulfoxide as adjuvant under two heating regimes (water bath in formulation 1 and hot plate in formulation 2) as well as without heating in 50 % ethanol and 50 % water (v/v). The acaricidal activity was assessed by the modified larval packet test, and the solubilization behavior was investigated by ultraviolet-visible spectroscopy, based on the Beer-Lambert law. With formulations 1 and 2, the mortality was greater than 95 % starting at the thymol concentrations of 5.0 and 7.5 mg/ml, respectively, while with formulation 3, this mortality level was reached starting at a concentration of 2.5 mg/ml, showing that the addition of ethanol in the solution enhanced the acaricidal action of thymol. This result was supported by the LC 90 values, which were 3.3, 2.4, and 1.6 mg/ml of thymol for formulations 1, 2, and 3, respectively. This result is related to the better solubility of thymol in the hydroethanolic formulation, since the spectroscopic analysis revealed that the thymol dissolved more completely in this formulation. This fact was evident once the R (2) obtained from the linear regression analysis of the relation absorbance × concentration of the formulations 1, 2, and 3 approached the optimal value (R (2) = 1) in the following sequence: 1, 2, and 3 (0.717, 0.901, and 0.968, respectively).
Nong, Xiang; Tan, Yong-Jian; Wang, Jia-Hai; Xie, Yue; Fang, Chun-Lin; Chen, Lin; Liu, Tian-Fei; Yang, De-Ying; Gu, Xiao-Bin; Peng, Xue-Rong; Wang, Shu-Xian; Yang, Guang-You
The aim of this study was to evaluate the acaricidal activity of a botanical extract from Eupatorium adenophorum against the hard tick Haemaphysalis longicornis. This could result in developing effective extracts of E. adenophorum as a source of natural, low-toxicity plant-based acaricidal drugs. Adult engorged females of H. longicornis were collected from naturally infected goats. The engorged females were reared in the laboratory and their offspring (larvae and nymphs) were used as test ectoparasites. The toxic effects of botanical extracts from E. adenophorum against larvae and nymphs of H. longicornis were evaluated. The results showed that the extracts with 1.5 and 1.0g/ml (w/v) concentrations were toxic for H. longicornis, comparable to a toxic effect of 2% chlorpyrifos (positive control). The median lethal time (LT50) for larval and nymphal ticks with 1.5g/ml (w/v) concentration of extract were 0.790 (LT99=1.065) and 1.018 (LT99=10.608) hours, respectively, whereas the LT50 of 1.0g/ml (w/v) concentration were 1.445 (LT99=6.047) and 1.313 (LT99=29.932) hours for larval and nymphal ticks, respectively. At a concentration of 1.5g/ml (w/v), an acaricidal effect of 100% was achieved for both larval and nymphal ticks, while a concentration of 1.0g/ml (w/v) resulted in 100% (for larvae) and 93% (for nymphs) within a 6h period. In additional, we found that the relatively low concentration (0.5g/ml) also obtained a good acaricidal effect during the short experimental period, with 2.22 and 2.651h LT50 for larval and nymphal ticks, respectively. These results indicate that E. adenophorum contains potent acaricidal ingredients against the hard tick H. longicornis.
Field testing tick repellents intended for use on human skin can be difficult, particularly when multiple concentrations of multiple repellents must be tested. Therefore, laboratory tests using laboratory reared ticks have been important. To address concerns that test results obtained with laborator...
Hexane extract of chinaberry, Melia azedarach L., unripe fruits obtained from different municipalities of Goias state in Brazil were evaluated on the southern cattle fever tick, Rhipicephalus microplus (Canestrini), engorged females. Hexanic extracts were assayed in decreasing concentrations from 0....
McIntosh, Douglas; Bezerra, Rodrigo Alves; Luz, Hermes Ribeiro; Faccini, João Luiz Horacio; Gaiotto, Fernanda Amato; Giné, Gastón Andrés Fernandez; Albuquerque, George Rego
Studies investigating rickettsial infections in ticks parasitizing wild animals in the Northeast region of Brazil have been confined to the detection of Rickettsia amblyommii in immature stages of Amblyomma longirostre collected from birds in the state of Bahia, and in immatures and females of Amblyomma auricularium collected from the striped hog-nosed skunk (Conepatus semistriatus) and armadillos (Euphractus sexcinctus) in the state of Pernambuco. The current study extends the distribution of R. amblyommii (strain Aranha), which was detected in A. longirostre collected from the thin-spined porcupine Chaetomys subspinosus and the hairy dwarf porcupine Coendou insidiosus. In addition, we report the first detection of Rickettsia bellii in adults of A. longirostre collected from C. insidiosus in the state of Bahia.
Garcia, Marcos Valério; Andreotti, Renato; Reis, Fernando Alvarenga; Aguirre, André de Abreu Rangel; Barros, Jacqueline Cavalcante; Matias, Jaqueline; Koller, Wilson Werner
Hair sheep breeds are a new, cost-effective option for the diversification of livestock in the Midwest region of Brazil. They are grazed extensively with cattle as well as in isolation in small areas. Hair sheep breeds are vulnerable to infestation by parasites such as the cattle tick, Rhipicephalus microplus, which causes various types of damage and can transmit diseases. In this study, Santa Inês hair sheep were naturally infested in an area contaminated by infested cattle and then monitored to determine the ability of these animals to maintain the local tick population in the absence of cattle. After engorged tick females of each generation fell off, the animals were placed in another pasture and were returned only after larvae reappeared in the original pasture. Tick counts were performed every ten days for three generations of sheep, and average infestations per animal of 34, 12 and 4 ticks were observed for each successive generation. These numbers suggest the acquisition of resistance; however, additional studies are needed to ensure resistance is achieved. The average length of the parasitic phase for each generation of ticks was 25 days. We concluded that this hair sheep breed, even if kept separate from cattle, is able to maintain tick populations for at least three generations, although a gradual decrease in the population levels of R. microplus over three generations was observed. We also detected two positive cases of Anaplasma spp. Therefore, it appears that the Santa Inês hair sheep breed contributes to the circulation of this bacterium among other ruminants.
Bharadwaj, Anuja; Hayes, Laura E; Stafford, Kirby C
We conducted field trials to evaluate the ability of a garlic juice-based product to control or suppress nymphal activity of the blacklegged tick, Ixodes scapularis Say, at residential properties in Connecticut in 2009, 2010, and 2011. The product was applied at a rate of 0.2 g AI/m2. Percent control of nymphal densities achieved by the spray treatment at 6, 11, and 18 d postspray for the 3 yr was 37.0, 59.0, and 47.4%, respectively. Differences between nymphal densities were greatest during the first post-spray sampling period. While garlic may require multiple applications for the suppression of tick activity, this product could provide a minimal-risk option for the short-term control of nymphal I. scapularis in the residential landscape. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Tomassone, L; Pagani, P; De Meneghi, D
A reverse line blot hybridisation (RLB) assay was applied to screen Amblyomma variegatum adult ticks (n = 504) collected from N'Dama cattle in the Republic of Guinea. In a PCR, the V1 hypervariable region of the 16S ribosomal RNA (rRNA) gene was amplified with a set of primers unique for species of the genera Anaplasma and Ehrlichia, and the V4 hypervariable region of the 18S rRNA gene was amplified with primers specific for members of the genera Theileria and Babesia. Amplified PCR products from A. variegatum ticks were hybridised onto a membrane, to which oligonucleotide probes species-specific for Ehrlichia/Anaplasma and Theileria/Babesia parasites were covalently linked. No pathogens belonging to Ehrlichia/Anaplasma species were found, while 10 DNA samples resulted positive for Babesia caballi and 5 samples for Theileria velifera. This is the first report of B. caballi in A. variegatum ticks. One of the B. caballi positive samples was sequenced. This new strain (BcabGuinea) showed a 97% similarity to the Z15104 B. caballi GenBank sequence.
Gerardi, Monize; Martins, Maria Marlene; Nava, Santiago; Szabó, Matias Pablo Juan
Amblyomma parvum is a Neotropical tick that is widely spread and a potential vector of pathogens, including Rickettsiae. Genetic differences are remarkable between A. parvum populations from Brazil and Argentina. In this work, feeding and reproduction parameters of A. parvum ticks from these two populations were compared on some key host species to evaluate possible differences in host suitability between them. On the whole parameters of these tick populations were similar when fed on the same host and varied similarly on different host species. Still, bovines were more suitable host for Argentinian larvae than for Brazilian cohorts. It was observed that guinea pigs were the best host A. parvum immatures from both origins, as depicted from higher recovery rate of larvae and heavier engorged nymph weights. Canids and bovids were host species most suitable to adults of both tick populations as shown by the highest number of larvae produced by adult females that engorged on these hosts. Taken together, results showed that in spite of the genetic divergence, A. parvum from Argentina and Brazil have similar biological performance on various host species.
Hilburn, L R; Gunn, S J; Castillo, C
A survey of Amblyomma Koch tick populations in southern Texas revealed that A. imitator Kohls was restricted to the two most southern counties, but that A. cajennense (Fabricius) ranged at least as far north as Kingsville, Tex. Females of the two species could be distinguished by the presence of chitinous tubercles on the festoons of A. cajennense and the presence of projections over both sides of the apron of the genital aperture in A. imitator. Males were distinguished by size, ornamentation, and the elongate ventral scutes of A. imitator. In addition, six enzymes, AATA, ACONA, IDH2, LDH, MPI, and PEP, were diagnostic for the two species and two others, aGPD and ACONC, had high diagnostic values. Resulting interspecific divergence was significant, I = 0.582. Genetic variability was higher in A. imitator (h = 0.092) than in A. cajennense (h = 0.057), but neither species exhibited marked interpopulation divergence (I = 0.991 in A. imitator, I = 0.994 in A. cajennense).
Rosen, M E; Hamer, S A; Gerhardt, R R; Jones, C J; Muller, L I; Scott, M C; Hickling, G J
Lyme disease (LD), caused by the bacterium Borrelia burgdorferi and transmitted in the eastern United States by blacklegged ticks, Ixodes scapularis Say, is classified as nonendemic in Tennessee and surrounding states in the Southeast. Low incidence of LD in these states has been attributed, in part, to vector ticks being scarce or absent; however, tick survey data for many counties are incomplete or out of date. To improve our knowledge of the distribution, abundance, and Borrelia spp. prevalence of I. scapularis, we collected ticks from 1,018 hunter-harvested white-tailed deer (Odocoileus virginianus (Zimmerman)) from 71 of 95 Tennessee counties in fall 2007 and 2008. In total, 160 deer (15.7%) from 35 counties were infested with adult I. scapularis; 30 of these counties were new distributional records for this tick. The mean number of I. scapularis collected per infested deer was 5.4 +/- 0.6 SE. Of the 883 I. scapularis we removed from deer, none were positive for B. burgdorferi and one tested positive for B. miyamotoi. Deer are not reservoir hosts for B. burgdorferi; nevertheless, past surveys in northern LD-endemic states have readily detected B. burgdoreferi in ticks collected from deer. We conclude that I. scapularis is far more widespread in Tennessee than previously reported. The absence of detectable B. burgdorferi infection among these ticks suggests that the LD risk posed by I. scapularis in the surveyed areas of Tennessee is much lower than in LD-endemic areas of the Northeast and upper Midwest.
Livanova, N N; Livanov, S G
A count of the tick species Ixodes persulcatus Schulze, 1930 was carried out in the "Denezhkin Kamen" Nature Reserve and adjacent territories (the Severoural'sk and Ivdel' Districts of the Sverdlovsk Region, the Northern Urals geographical province) in the 2005. The abundance and distribution of unengorged adults has been evaluated on an area of 22.5 square kilometers (N 60 degrees 27'-60 degrees 30' E 059 degrees 38'-059 degrees 42'). The area includes proportionally main landscape and vegetation elements of the region studied, from mountain analogues of the middle and northern taiga up to tundra. One tick species, I. persulcatus, has been collected by flagging with the abundance from 0.4 up to 6.8 (average 1.6 +/- 0.9) specimens per flag-hour. The observed values of abundance are classified into three classes (I - ticks are absent, II - 1-2 specimens, and III - 3-7 specimens per flag-hour). The class I amounts 20, II - 75, and III - 5% of the area examined. It has been revealed by the expert evaluation of the 2003-2004 and counts of the 2005 that ticks occur stably in the Northern Ural, reaching N 61 degrees and 400 m above sea level. The level of the species abundance remained constant till the middle of summer. In this period the activity of ticks dependent on the weather optimum only.
Flores-Fernández, José Miguel; Gutiérrez-Ortega, Abel; Padilla-Camberos, Eduardo; Rosario-Cruz, Rodrigo; Hernández-Gutiérrez, Rodolfo; Martínez-Velázquez, Moisés
The cattle tick Rhipicephalus (Boophilus) microplus is the most economically important ectoparasite affecting the cattle industry in tropical and subtropical areas around the world. The principal method of tick control has relied mainly on the use of chemical acaricides, including ivermectin; however, cattle tick populations resistant to ivermectin have recently been reported in Brazil, Mexico, and Uruguay. Currently, the molecular basis for ivermectin susceptibility and resistance are not well understood in R. microplus. This prompted us to search for potential molecular targets for ivermectin. Here, we report the cloning and molecular characterization of a R. microplus glycine-like receptor (RmGlyR) gene. The characterized mRNA encodes for a 464-amino acid polypeptide, which contains features common to ligand-gated ion channels, such as a large N-terminal extracellular domain, four transmembrane domains, a large intracellular loop and a short C-terminal extracellular domain. The deduced amino acid sequence showed around 30% identity to GlyRs from some invertebrate and vertebrate organisms. The polypeptide also contains the PAR motif, which is important for forming anion channels, and a conserved glycine residue at the third transmembrane domain, which is essential for high ivermectin sensitivity. PCR analyses showed that RmGlyR is expressed at egg, larval and adult developmental stages. Our findings suggest that the deduced receptor is an additional molecular target to ivermectin and it might be involved in ivermectin resistance in R. microplus. PMID:25174962
Grech-Angelini, Sébastien; Stachurski, Frédéric; Lancelot, Renaud; Boissier, Jérôme; Allienne, Jean-François; Marco, Sylvain; Maestrini, Oscar; Uilenberg, Gerrit
Corsica is a mountainous French island in the north-western Mediterranean presenting a large diversity of natural environments where many interactions between domestic animals and wild fauna occur. Despite a favourable context for ticks and tick-borne diseases (TBDs), the tick fauna of Corsica has not systematically been investigated. For one year (May 2014-May 2015), a survey of ticks infesting cattle was performed in the three Corsican cattle slaughterhouses. Two of these were visited monthly and one quarterly; the ticks were manually collected, just after flaying. Ticks were identified on their morphology; when necessary, some specimens were also molecularly identified by sequencing mitochondrial cox1 (cytochrome c oxidase subunit 1) and 16S ribosomal RNA genes and ITS2 (internal transcribed spacer 2). During the same period, ticks from other domestic animals (small ruminants, horses, domestic carnivores) and wild animals (wild boars, mouflons, deer) were occasionally collected. A total of 1,938 ticks was collected from 264 of 418 cattle examined, reared in 86 different localities. Eight tick species were found infesting cattle: Rhipicephalus bursa (56.1 %), Hyalomma marginatum (21.5 %), Hy. scupense (8.7 %), Ixodes ricinus (5.7 %), Haemaphysalis punctata (4.8 %), Rh. sanguineus (sensu lato) (2.3 %), Rh. (Boophilus) annulatus (0.7 %) and Dermacentor marginatus (0.2 %). The cattle infestation rate remained high all year (more than 50 %). Several tick species showed seasonal variation of their activity. From other Corsican animals 1,196 ticks were collected. Comparing ticks collected from cattle with those found on other animals, several host preferences were shown. A noteworthy record is that of a few Ha. sulcata on mouflons which were mainly infested by Rh. bursa. The Corsican tick fauna is characterized by typical Mediterranean species (Rh. bursa and Hy. marginatum), but the mild climate and diversified environment provide satisfactory habitats both for species usually found in dry areas (Hy. scupense) and species usually collected in humid areas (I. ricinus).
Eisen, Rebecca J.; Eisen, Lars; Beard, Charles B.
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
Vilcins, Inger-Marie E; Kosoy, Michael; Old, Julie M; Deane, Elizabeth M
A total of 42 ticks comprising Ixodes tasmani (n = 41) and Ixodes trichosuri (n = 1) were collected from wild koalas (Phascolarctos cinereus) at the Koala Convention Centre, Philip Island, Victoria, Australia and screened for the presence of Bartonella using the target gene gltA. Bartonella-like DNA was detected in 4 of the 19 pooled tick samples (21%). All positive ticks were male. Analysis of partial sequences for the gltA gene indicated the presence of a Bartonella-related species similar to that reported in another Ixodid species. This is the first report of Bartonella-like organisms in a native Australian marsupial.
Though largely eradicated from the U.S. for the past half century, the reemergence of populations of southern cattle tick (Rhipicephalus (Boophilus) microplus) is of major concern to the U.S. cattle industry. Southern cattle ticks are vectors of blood parasites that cause a lethal cattle disease, es...
Roth, Tara; Lane, Robert S; Foley, Janet
Francisella tularensis and Rickettsia spp. have been cultured from Haemaphysalis leporispalustris Packard, but their prevalence in this tick has not been determined using modern molecular methods. We collected H. leporispalustris by flagging vegetation and leaf litter and from lagomorphs (Lepus californicus Gray and Sylvilagus bachmani (Waterhouse)) in northern California. Francisella tularensis DNA was not detected in any of 1,030 ticks tested by polymerase chain reaction (PCR), whereas 0.4% of larvae tested in pools, 0 of 117 individual nymphs, and 2.3% of 164 adult ticks were PCR-positive for Rickettsia spp. Positive sites were Laurel Canyon Trail in Tilden Regional Park in Alameda Contra Costa County, with a Rickettsia spp. prevalence of 0.6% in 2009, and Hopland Research and Extension Center in Mendocino County, with a prevalence of 4.2% in 1988. DNA sequencing revealed R. felis, the agent of cat-flea typhus, in two larval pools from shaded California bay and live oak leaf litter in Contra Costa County and one adult tick from a L. californicus in chaparral in Mendocino County. The R. felis in unfed, questing larvae demonstrates that H. leporispalustris can transmit this rickettsia transovarially. Although R. felis is increasingly found in diverse arthropods and geographical regions, prior literature suggests a typical epidemiological cycle involving mesocarnivores and the cat flea, Ctenocephalides felis. To our knowledge, this is the first report of R. felis in H. leporispalustris. Natural infection and transovarial transmission of this pathogen in the tick indicate the existence of a previously undocumented wild-lands transmission cycle that may intersect mesocarnivore-reservoired cycles and collectively affect human health risk.
The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, spends as much as 80–90% of its life cycle as a larva questing for a host. Standard control methods are limited to on-host applications, leaving a need for methods directed at the pasture infesting stages. Reports from Brazil indic...
Zhioua, E; Ginsberg, H S; Humber, R A; Lebrun, R A
Free-living larval, nymphal, and adult Ixodes scapularis Say were collected from scattered locales in southern New England and New York to determine infection rates with entomopathogenic fungi. Infection rates of larvae, nymphs, males, and females were 0% (571), 0% (272), 0% (57), and 4.3% (47), respectively. Two entomopathogenic fungi were isolated from field-collected I. scapularis females from Fire Island, NY. Isolates were identified as Verticillium lecanii (Zimmermann) Viegas and Verticillium sp. (a member of the Verticillium lecanii species complex).
the extent of ornamentation and the degree of punctationmare highly variable . Therefore, while we are listing this name for the sake of...Agropecuaria Rafaela del Instituto Nacional de Tecnologfa Agropecuada and to the Consejo Nacional de Investigaciones Cientfficas y T6cnicas, Argentina
Allan, S A; Patrican, L A
The efficacy of two commercially available formulations of a desiccant and insecticidal soap were compared with chlorpyrifos wettable powder (0.6 kg [AI]/ha) against the immatures of Ixodes scapularis Say in a woodlot in Westchester County, New York. The desiccant formulation (Drione) was applied at 61.04 kg/ha and an insecticidal soap (Safer's) was applied as a mixture (39 ml concentrate per liter of water) at 107 liters/ha. By 1 wk after application, all treatments significantly reduced the density of nymphs in comparison to untreated plots. Only plots treated with chlorpyrifos had significantly reduced nymphal densities 2 wk after application. By 6 wk after application, there were no differences in nymphal density between treated and untreated plots, which was likely the result of a decline in overall nymphal populations. None of the treatments against nymphs affected larval densities sampled 6 wk after application. Larval density was significantly lower 1 wk after application in plots treated with chlorpyrifos and Safer's insecticidal soap than in untreated plots. By 2 wk after treatment, only plots treated with chlorpyrifos had lower larval densities than untreated plots. Results indicate that the desiccant Drione and Safer's insecticidal soap are good for short-term control of immature I. scapularis.
Martins, João R; Salomão, Edson L; Doyle, Rovaina L; Teixeira, Mariana C; Onofrio, Valeria C; Barros-Battesti, Darci M
A female of Amblyomma aureolatum was found on the howler monkey Alouatta guariba, in Cachoeira do Sul, Rio Grande do Sul, Southern Brazil. This is the first record of this tick species parasitizing this primate species in Brazil.
Brugger, Katharina; Boehnke, Denise; Petney, Trevor; Dobler, Gerhard; Pfeffer, Martin; Silaghi, Cornelia; Schaub, Günter A; Pinior, Beate; Dautel, Hans; Kahl, Olaf; Pfister, Kurt; Süss, Jochen; Rubel, Franz
The castor bean tick Ixodes ricinus (L.) is the principal vector for a variety of viral, bacterial, and protozoan pathogens causing a growing public-health issue over the past decades. However, a national density map of I. ricinus is still missing. Here, I. ricinus nymphs in Germany were investigated by compiling a high-resolution map depicting the mean annually accumulated nymphal density, as observed by monthly flagging an area of 100 m(2) Input data comprise ticks collected at 69 sampling sites. The model domain covers an area of about 357,000 km(2) (regional scale). Two negative binomial regression models were fitted to the data to interpolate the tick densities to unsampled locations using bioclimatic variables and land cover, which were selected according to their significance by the Akaike information criterion (AIC). The default model was fitted to the complete dataset resulting in AIC = 842. An optimized model resulted in a significantly better value of AIC = 732. Tick densities are very low in urban (green) areas. Maximum annual densities up to 1,000 nymphs per 100 m(2) are observed in broad-leaved forests. The tick maps were verified by leave-one-out cross-validation. Root mean square errors of RMSE = 137 and RMSE = 126 nymphs per 100 m(2) were estimated for the two models, respectively. These errors are of the order of the interannual variation of the tick densities. The compilation of a high-resolution density map of unfed nymphal I. ricinus for Germany provides a novel, nationwide insight into the distribution of an important disease vector. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Hahn, Micah B; Jarnevich, Catherine S; Monaghan, Andrew J; Eisen, Rebecca J
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. 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 United States.
Veronez, Viviane Aparecida; Freitas, Beatriz Zanolli; Olegário, Maria Marlene Martins; Carvalho, William Mendes; Pascoli, Graziela Virginia Tolesano; Thorga, Khelma; Garcia, Marcos Valério; Szabó, Matias Pablo Juan
Cerrado biome, the South American savannah, covers about 2 million km(2) and is very rich in endemic species but threatened by agriculture. In this report free-living tick species are presented, and their seasonal and relative distribution within the various phytophysiognomies in a small Cerrado reserve in Minas Gerais State, Brazil. Overall 2,694 free-living ticks were found during a 2 years sampling period with CO(2) traps and cloth dragging. Of these, 73.5% were Amblyomma cajennense and 0.6% Amblyomma dubitatum. All other ticks (25.9%) were retained as Amblyomma spp. Adults of A. cajennense peaked in spring, the nymphs in winter of both years. Amblyomma larval clusters were found in autumn and winter. Adult ticks (46.7%) and nymphs (39.5%) were most often found in woodlands, whereas most larval clusters were found in valley-side marshes (39%). Amblyomma cajennense, Anocentor nitens, Rhipicephalus (Boophilus) microplusand Rhipicephalus sanguineus ticks were found on domestic animals from neighboring properties. Search for Rickettsia in the hemolymph of 497 A. cajennense and one A. dubitatum ticks yielded negative results. Results confirmed earlier reports on the overwhelming prevalence of A. cajennense ticks in the Cerrado biome of Brazil and added information to habitat preferences of this tick species, a major vector in Brazil of the Rocky Mountain spotted fever.
Vassallo, M; Pichon, B; Cabaret, J; Figureau, C; Pérez-Eid, C
To assess the Lyme borreliosis vector population density we set up a methodology for sampling the Ixodes ricinus L. population host questing on the vegetation. We focused on the collection of the nymphal stage, which is the principal stage of disease transmission to humans. This study was carried out in Rambouillet forest (Yvelines, France) where seven study areas were demarcated. These areas are maximally homogeneous for plant species using a finer scale than the phytosociological classification as defined by the method of landscape diagnostics. Out of 23 collections performed from March 1997 to May 1998, 2,906 I. ricinus nymphs were collected. The sampling technique chosen was the cloth lure technique. The technical parameters were studied and fixed (cloth type, cloth size, sample size, researcher position). It appeared that toweling was the best cloth type to optimize the number of ticks collected; the position of the researcher had no effect on tick samples. To satisfy the criteria for correct sampling, we studied representativity, randomness, and nonselectivity of our methodology. The spatial distribution of nymphs in a homogeneous area was close to random and thus very few subsamples were needed to obtain a relative density which was representative. No significant differences were found between random samples and following transect samples; and nonselectivity was totally satisfied because we only worked on questing nymphs. We grouped the samples that presented no significant differences to attribute a density index, which varied from 0 to 5. This methodology, applied with the same parameters, offers potential for producing comparable results from studies in different geographical areas and at different times of the years.
Barros-Battesti, Darci M; Ramirez, Diego G; Sampaio, Janio dos Santos; Famadas, Katia M; Faccini, João Luiz H; Nunes, Pablo Henrique; Martins, Thiago F; Ogrzewalska, Maria; Labruna, Marcelo B; Marcili, Arlei; Barbieri, Fabio da Silva
The description of the larva of Amblyomma romitii Tonelli-Rondelli is based on optical and scanning electron microscopy. Larvae were obtained under laboratory conditions from an engorged female collected on capybara from Rurópolis municipality, State of Pará, Northern Brazil. Several characters are presented including the chaetotaxy of idiosoma, palpi and Haller's organ. The larval porotaxy (topographical and numerical patterns of integumentary structures) was presented and compared to that of the other Amblyomma spp. larvae. The mitochondrial 16S rDNA partial sequence of A. romitii generated in the present study was aligned with sequences previously determined for other Amblyomma species available in Genbank and with some species presently sequenced. The larval morphology of A. romitii and other Neotropical Amblyomma spp. larvae is discussed as well as the DNA sequence and its phylogenetic position among other species of the genus.
Lima, Cássia A; Torquato, Ricardo J S; Sasaki, Sergio D; Justo, Giselle Z; Tanaka, Aparecida S
A novel chymotrypsin inhibitor identified in fat body and hemocyte cDNA libraries of Boophilus microplus was named BmCI (B. microplus Chymotrypsin Inhibitor) (Genbank EU636772). The putative BmCI amino acid sequence presented a 22-residue-signal peptide and 58-residue-mature protein. BmCI amino acid sequence analysis allowed its classification as a Kunitz-BPTI inhibitor with six cysteine residues, a theoretical pI of 7.8, and the presence of Tyr at P1 position in the putative reactive site, suggesting inhibitory activity toward chymotrypsin. In this work, we reported the biochemical characterization of BmCI. The recombinant BmCI expressed in yeast Pichia pastoris was purified by size exclusion and reverse phase chromatographies. rBmCI expression yield was of 1mgL(-1) of culture. Purified rBmCI confirmed its chymotrypsin inhibitory activity with a low K(i) (6.2pM). The BmCI gene expression analysis by semi-quantitative RT-PCR indicated its transcription in the hemocytes, salivary gland and ovary. The cytotoxic activity of purified rBmCI was demonstrated in BALB/c 3T3 mouse fibroblasts. As assessed by the MTT reduction assay, rBMCI induced a dose-dependent decrease in 3T3 fibroblasts viability (IC(50)=8microM). Moreover, flow cytometry analysis revealed that rBmCI is able to induce apoptosis, whereas no effect was observed on cell cycle progression. In conclusion, we demonstrated that rBmCI is cytotoxic against mammalian cells and obtained evidence that this growth inhibition is caused by an apoptosis-inducing activity.
Barci, Leila A G; de Almeida, José Eduardo M; de Campos Nogueira, Adriana H; Zappelini, Luciano O; do Prado, Angelo P
This study was carried out to select isolates of the entomopathogenic fungus Beauveria bassiana with pathogenic potential to control the Rhipicephalus (Boophilus) microplus tick. The effectiveness of thirty isolates was first tested at a concentration of 5 x 108 conidia.mL(-1). Of these, eight were evaluated (IBCB01, IBCB02, IBCB07, IBCB17, IBCB21, IBCB74, IBCB149, IBCB165) and showed an effectiveness between 90 and 99%; thirteen (IBCB03, IBCB14, IBCB16, IBCB24, IBCB95, IBCB97, IBCB102, IBCB141, IBCB146, IBCB147, IBCB150, IBCB154, IBCB157) between 80 and 89,5%; six (IBCB47, IBCB75, IBCB84, IBCB145, IBCB161, IBCB164) between 70 and 79%, and only two (IBCB13 and IBCB143) had lower pathogenicity (70% or below). In the second step of the study, the five more effective strains in the first phase of the experiment (IBCB01, IBCB07, IBCB21, IBCB66, IBCB165) were analyzed comparatively. Based on in vitro results, it can be concluded that IBCB66 and IBCB21 are the isolates with higher potential for field control of R. (B.) microplus. IBCB01, IBCB07, IBCB21, IBCB66 e IBCB165 isolates were submitted to a conidial production test using a rice-based substrate. The best mass production of the entomopathogenic fungus was obtained with the IBCB66 strain.
Rhipicephalus microplus, the cattle fever tick, is a global economic problem to the cattle industry due to direct infestation of cattle and pathogens transmitted during feeding. Cattle fever tick outbreaks continue to occur along the Mexico-U.S. border even though the tick has been eradicated from t...
Hahn, Micah; Jarnevich, Catherine S.; Monaghan, Andrew J.; Eisen, Rebecca J.
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.
Szabó, Matias P J; Labruna, Marcelo B; Castagnolli, Karina C; Garcia, Marcos V; Pinter, Adriano; Veronez, Viviane A; Magalhães, Geórgia M; Castro, Márcio B; Vogliotti, Alexandre
While conducting projects on ticks from deer and on tick ecology in animal trails in an Atlantic rainforest reserve in Southeastern Brazil, researchers of our group were bitten by ticks several times. Some of these episodes were recorded. Three species of adult ticks attached to humans: Amblyomma brasiliense Aragão, Amblyomma incisum Neumann, and Amblyomma ovale Koch. Eight nymphal attachments with engorgement on humans were recorded. From these, six molted to adults of A. incisum, one to an adult of A. brasiliense, and one had an anomalous molting, therefore the adult tick could not be properly identified. Local reactions to tick attachment varied among individual hosts from almost imperceptible to intense. Especially itching, but hyperemia and swelling as well, were prominent features of the reaction. Overall it can be affirmed that human beings can be a physiologically suitable host species for ticks in the Atlantic rainforest and that itching was an important if not the major component of the resistance to tick bite.
Barbieri, Fábio S; Brito, Luciana G; Labruna, Marcelo B; Barros-Battesti, Darci M; Camargo, Luis Marcelo A; Famadas, Kátia M
The larval stage of Amblyomma calcaratum Neumann is described using optical and scanning electron microscopy. Unfed larvae were obtained from a colony of A. calcaratum originating from engorged females collected on Tamandua tetradactyla in the Jaraguá Mountain (23°40'S, 45°44'W), São Paulo County, Brazil. Eleven larvae were prepared and mounted on slides and observed under a light microscope equipped with a drawing tube. Three specimens were prepared for SEM. Several morphological characters are described, including the chaetotaxy of the idiosoma, palpi, and Haller's organ, as well as morphological features of the idiosoma, gnathosoma, and legs of A. calcaratum larvae. In addition, topographical and numerical patterns of integumentary structures on the larval idiosoma are described using a recently proposed nomenclature. On the idiosoma, setaes, lyrifissures, small glands, and large wax glands were found. These structures were observed isolated or associated over the entire idiosoma, except on the scutum, which lacks large wax glands. The topographical and numerical patterns of integumentary structures of the A. calcaratum larva showed only minor differences when compared with patterns of other Amblyomma larvae; however, a few key features can be used to differentiate A. calcaratum from other members of this genus. Copyright © 2013 Elsevier GmbH. All rights reserved.
Burtis, J C; Ostfeld, R S; Yavitt, J B; Fahey, T J
We explored the relationship between the diversity and abundance of the soil arthropod predator community and the overwinter survival of engorged larval Ixodes scapularis Say under variable snow cover in a hardwood forest. We reduced the snow cover over 30 soil core field microcosms, simulating predicted changes in snow pack in the northeastern United States. An additional 29 microcosms were used as references with no snow pack manipulation. Each microcosm contained 15 engorged larval I. scapularis. We expected lower soil temperature without insulating snow cover to reduce tick survival. However, we observed that reduced snow cover had no effect, with 44.2 and 44.7% overwintering successfully in the reference and snow-removal plots, respectively. Increasing taxonomic family richness of arthropod predators and the total number of large (>1 mm) arthropod predators significantly reduced the overwinter survivorship of I. scapularis within the microcosms. Small (<1 mm) arthropod predator abundance had no effect. Our results suggest that forests with complex natural arthropod predator communities show reduced tick survival.
Dutta, S; Godara, R; Katoch, R; Yadav, A; Katoch, M; Singh, N K
Detection of resistance levels against amitraz and malathion in Rhipicephalus (Boophilus) microplus collected from four districts of Jammu region (India) was carried out using the adult immersion test. The regression graphs of probit mortality of ticks plotted against log values of concentration of drugs were utilised for the determination of slope of mortality, lethal concentration for 50% (LC50), 95% (LC95) and resistance factor (RF). On the basis of the data generated on variables (mortality, egg mass weight, reproductive index and percentage inhibition of oviposition) the resistance level was categorised as I, II, III and IV. Out of these four districts, resistance to amitraz was detected at level I in Udhampur (RF = 2.81), Jammu (RF = 2.53) and Samba isolates (RF = 2.24) whereas Rajouri isolate was found susceptible (RF = 1.0). Resistance to malathion was detected at level I in Udhampur (RF = 4.01) and Jammu isolates (RF = 1.76) whereas Rajouri (RF = 0.472) and Samba (RF = 0.199) isolates were found susceptible. The data generated on amitraz and malathion resistance status will help in formulating a tick control strategy in the region.
Shemshad, Masoomeh; Shemshad, Khadijeh; Sedaghat, Mohammad Mehdi; Shokri, Majid; Barmaki, Alireza; Baniardalani, Mojgan; Rafinejad, Javad
Objective To carry out the distribution survey of hard ticks of livestock in Boeen Zahra and Takistan counties of Qazvin province from April 2010 to September 2010. Methods Nearly about 2 638 sheep, 461 goats and 318 cattle of 38 herds in different geographical areas were searched for tick infestation. Results The species compositions collected from the livestock of Boeen Zahra and Takistan were Haemaphysalis concinna (0.63%), Haemaphysalis sulcata (12.66%), Hyalomma anatolicum (3.80%), Hyalomma asiaticum (3.16%), Hyalomma detritum (5.70%), Hyalomma dromedarii (28.48%), Hyalomma marginatum (13.29%), Hyalomma schulzei (1.89%), Rhipicephalus bursa (3.16%) and Rhipicephalus sanguineus (3.16%), and for Takistan's livestock were Hyalomma dromedarii (9.86%), Hyalomma marginatum (13.29%), Hyalomma schulzei (1.89%) and Rhipicephalus sanguineus (3.16%), respectively. Hard ticks compositions in different topographic areas were different. Hyalomma species had the most prevalence in the areas. Conclusions The veterinary and public health investigation of the above species should be taken. PMID:23569956
Grigoryeva, L A; Stanyukovich, M K
The life cycle of Ixodes persulcatus lasts 3 years in the conditions of the Leningrad province (North-West Russia), the development of each phase taking a year. The normal age of the taiga tick is 3 years. The calendar age of larvae and nymphs reaches 11-12 months under favorable abiotic and biotic factors, while the calendar age of adults does not exceed 11 months. At the preimaginal phases of development the ticks that breed in August can feed before or after winter. However, their metamorphosis begins and reaches completion within the same timeframes (from late June to early August) and lasts for about 30-50 (60) days. The survival rate of hungry and engorged larvae and nymphs after wintering is quite high (88.6-100 %). We explain the low activity of larvae and nymphs in late summer and autumn by incomplete development. Morphogenetic diapause of engorged larvae and nymphs interrupts digestion but not metamorphosis which starts only in late June and July after the complete absorption of blood from the gut cavity.
Uspensky, Igor; Garruto, Ralph M; Goldfarb, Lev
The finding of an unfed adult female of the taiga tick Ixodes persulcatus Schulze is reported from the northern part of Eastern Siberia (the central part of the Sakha Republic [former Yakutia]) of Russia. This finding supplements other reported single findings of the taiga tick in different sites of the central part of the Sakha Republic, thus increasing its distributional range. The reproductive range of the taiga tick is limited to two separate areas in the southern parts of the Republic. The most probable mode of tick introduction northwards from the border of the reproductive range is by spring bird migrations from their wintering areas to breeding sites. The possibility of the establishment of stable tick populations in the areas of introduction is also considered.
Li, Andrew Y; Davey, Ronald B; Miller, Robert J; George, John E
The levels of resistance to two organophosphate acaricides, coumaphos and diazinon, in several Mexican strains of Boophilus microplus (Canestrini) were evaluated using the FAO larval packet test. Regression analysis of LC50 data revealed a significant cross-resistance pattern between those two acaricides. Metabolic mechanisms of resistance were investigated with synergist bioassays. Piperonyl butoxide (PBO) reduced coumaphos toxicity in susceptible strains, but synergized coumaphos toxicity in resistant strains. There was a significant correlation between PBO synergism ratios and the coumaphos resistance ratios. The results suggest that an enhanced cytochrome P450 monooxygenase (cytP450)-mediated detoxification mechanism may exist in the resistant strains, in addition to the cytP450-mediated metabolic pathway that activates coumaphos. PBO failed to synergize diazinon toxicity in resistant strains, suggesting the cytP450 involved in detoxification were specific. Triphenylphosphate (TPP) synergized toxicity of both acaricides in both susceptible and resistant strains, and there was no correlation between TPP synergism ratios and the LC50 estimates for either acaricide. Esterases may not play a major role in resistance to coumaphos and diazinon in those strains. Bioassays with diethyl maleate (DEM) revealed a significant correlation between DEM synergism ratios and LC50 estimates for diazinon, suggesting a possible role for glutathione S-transferases in diazinon detoxification. Resistance to coumaphos in the Mexican strains of B. microplus was likely to be conferred by both a cytP450-mediated detoxification mechanism described here and the mechanism of insensitive acetylcholinesterases reported elsewhere. The results of this study also underscore the potential risk of coumaphos resistance in B. microplus from Mexico to the U.S. cattle fever tick eradication program.
Nchu, Felix; Magano, Solomon R; Eloff, Jacobus N
In this study we examined the anti-tick properties of the essential oil of Tagetes minuta L. (Asteraceae: Asterales) against Hyalomma rufipes ticks. We obtained the essential oil of T. minuta by hydro-distillation of a combination of fresh flowers, leaves and soft stems, and analysed these by using gas chromatography (GC) and gas chromatography-linked mass spectrometry (GC-MS). The oil had a high percentage of monoterpenes and the major compounds identified were cis-ocimene (28.5%), beta-ocimene (16.83%) and 3-methyl-2-(2-methyl-2-butenyl)-furan (11.94%). Hyalomma rufipes adults displayed a significant (P < 0.05) dose repellent response to the essential oil of T. minuta. Probit analysis indicated a repellent EC50 of T. minuta essential oil for male ticks to be 0.072 mL/mL (CI 0.053 mL/mL to 0.086 mL/mL) and 0.070 mL/mL (CI 0.052 mL/mL to 0.084 mL/mL) for female ticks. There were no significant differences in repellent responses between male and female ticks. The oil also significantly (P < 0.05) delayed moulting of 60% of H. rufipes engorged nymphs. These results suggest that T. minuta may be a potential source of anti-tick agents.
Van Oosten, A R; Heylen, D J A; Jordaens, K; Backeljau, T; Matthysen, E
The endophilic tick Ixodes arboricola infests cavity-nesting birds, and its dispersal strongly depends on the movements of its host. Population genetic structure of I. arboricola was studied with seven polymorphic microsatellite markers. We collected 268 ticks from 76 nest boxes in four woodlots near Antwerp, Belgium. These nest boxes are mainly used by the principal hosts of I. arboricola, the great tit Parus major and the blue tit Cyanistes caeruleus. As these birds typically return to the same cavity for roosting or breeding, ticks within nest boxes were expected to be highly related, and tick populations were expected to be spatially structured among woodlots and among nest boxes within woodlots. In line with the expectations, genetic population structure was found among woodlots and among nest boxes within woodlots. Surprisingly, there was considerable genetic variation among ticks within nest boxes. This could be explained by continuous gene flow from ticks from nearby tree holes, yet this remains to be tested. A pairwise relatedness analysis conducted for all pairs of ticks within nest boxes showed that relatedness among larvae was much higher than among later instars, which suggests that larvae are the most important instar for tick dispersal. Overall, tick populations at the studied spatial scale are not as differentiated as predicted, which may influence the scale at which host–parasite evolution occurs. PMID:24781806
Ghosh, Srikanta; Tiwari, Shashi Shankar; Kumar, Bhanu; Srivastava, Sharad; Sharma, Anil Kumar; Kumar, Sachin; Bandyopadhyay, A; Julliet, Sanis; Kumar, Rajesh; Rawat, A K S
To develop an eco-friendly tick control method, seven plant extracts were prepared using 50 and 95% ethanol and evaluated for acaricidal activity against cattle tick, Rhipicephalus (Boophilus) microplus. The adult immersion test was adopted for testing different extracts. Based on 72 h screening criterion, 95% ethanolic extracts of Datura metel fruits and Argemone mexicana whole plant were found effective showing more than 50% mortality of treated ticks. The 95% ethanolic extracts of D. metel fruits and A. mexicana whole plant exhibited acaricidal and reproductive inhibitory effects on treated ticks. The LC90 values of D. metel and A. mexicana extracts were determined as 7.13 and 11.3%, respectively. However, although both the extracts were found efficacious against deltamethrin-resistant IVRI-4 and multi-acaricide resistant IVRI-5 lines of R. (B.) microplus, they caused less mortality than treated ticks of the reference IVRI-I line. Phytochemical studies indicated the presence of alkaloids and glucosides in D. metel fruits and alkaloids, terpenoids, flavonoids and phenolics in A. mexicana whole plant extracts. The results indicated that these botanicals may play an important role in reducing the use of chemicals for tick control and possibly to manage resistant tick population in environment friendly manner.
da Silva, Elis Maressa Gonçalves; Rodrigues, Vinicius da Silva; Jorge, Jaciara de Oliveira; Osava, Carolina Fonseca; Szabó, Matias Pablo Juan; Garcia, Marcos Valério; Andreotti, Renato
Ticks from Rhipicephalus sanguineus complex are widely distributed in the world and one species from this complex is the most common tick on dogs in Brazil, notably in urban areas. This tick is a vector of several diseases. Among others it transmits the agent of canine Ehrlichiosis, a major dog infectious disease and the agent of Rocky Mountain spotted fever. This tick can spread rapidly and develop intolerable infestations within no time. Currently tick control is done with acaricides and demand for such drugs has grown fast. However, R. sanguineus has already developed resistance to the main active compounds and the development of new acaricides is necessary. Many essential oils of plants have acaricidal effect and may be an important source of molecules for the synthesis of new acaricide products. In this study, we evaluated the effectiveness of a new herbal phytotherapic, consisting of the essential oil of Tagetes minuta L., against R. sanguineus in vitro and on dogs undergoing experimental infestations. The product displayed 100% efficacy against larvae, nymphs and adults of the tick on all tested conditions.
Mannelli, Alessandro; Nebbia, Patrizia; Tramuta, Clara; Grego, Elena; Tomassone, Laura; Ainardi, Romina; Venturini, Lucia; De Meneghi, Daniele; Meneguz, Pier Giuseppe
Birds belonging to 59 species (n = 1,206) were live captured in Piemonte, northwestern Italy, in 2001. Ixodes ricinus (L.) larvae were collected from 59 birds belonging to nine species, and nymphs were recovered on 79 birds belonging to 10 species. Eurasian blackbirds, Turdus merula L., had significantly higher levels of infestation by ticks than other passerine species. Larval I. ricinus of blackbirds peaked in summer, when prevalence was 39% (95% confidence interval 24.2-55.5) and mean number of ticks per host was 3.3 (1.6-7.2), whereas nymphs peaked in spring, when prevalence was 72.2% (54.8-85.8) and mean number of ticks per host was 6.9 (4.4-10.7). Immature I. ricinus were coincidentally aggregated on blackbirds, with 15 blackbirds feeding 67.4% of nymphs and 40.3% of larvae, and coinfestation by both stages was relatively high in summer: Kappa = 0.64 (0.40-0.88). Borrelia burgdorferi sensu lato was identified by polymerase chain reaction (PCR) in 58.3% (35.9-78.5) of larvae with engorgement ratio > or = 3 that were collected from blackbirds. Larvae that were collected from other passerine species gave negative PCR results. Sixteen of 21 PCR-positive samples belonged to B. garinii (76.2%), and five (23.8%) were Borrelia valaisiana. Results of this study suggest that blackbirds play an important role as hosts for immature I. ricinus and as reservoir of Borrelia garinii in northwestern Italy.
Carroll, J F; Klun, J A; Schmidtmann, E T
Unfed adult blacklegged ticks Ixodes scapularis Say, were tested under laboratory conditions for behavioral responses to substances rubbed from external glands on legs of white-tailed deer, Odocoileus virginianus (Zimmermann). In replicated trials, significantly more female ticks became stationary on portions of vertical glass tubing rubbed with the tarsal gland substances of both bucks and does than on nontreated tubing. This behavior, apparently an arrestant response, was infrequent among males. White-tailed deer urinate upon their tarsal glands, and doe urine also produced an arrestant response among female ticks. Metatarsal gland secretions of bucks elicited no arrestant response in either male or female I. scapularis, but doe metatarsal gland secretions elicited low-level positive responses from both sexes. A low-level arrestant response also was exhibited by females to secretions from the interdigital glands of bucks. In a second bioassay, three times as many females came to rest on the terminal ends of vertical glass rods whose bases were treated with secretions from buck interdigital glands than on rods with nontreated bases. This suggests that interdigital gland secretion influences blacklegged tick climbing behavior. Substances produced by or associated with the leg glands of O. virginianus may therefore serve as kairomones for host-seeking adult I. scapularis; interdigital gland secretions on soil or leaf litter may signal active deer trails, and tarsal gland substances may denote portions of vegetation contacted previously by white-tailed deer. In nature, use of these chemical cues by host-seeking adult I. scapularis may increase the probability of acquiring a suitable host.
Remedio, R N; Nunes, P H; Anholeto, L A; Oliveira, P R; Sá, I C G; Camargo-Mathias, M I
Neem (Azadirachta indica) has attracted the attention of researchers worldwide due to its repellent properties and recognized effects on the morphology and physiology of arthropods, including ticks. Therefore, this study aimed to demonstrate the effects of neem seed oil enriched with azadirachtin on salivary glands of Rhipicephalus sanguineus ticks, targets of great veterinary interest because of their ability to transmit pathogens to dogs. For this, R. sanguineus semi-engorged females were subjected to treatment with neem seed oil, with known azadirachtin concentrations (200, 400 and 600ppm). After dissection, salivary glands were collected and evaluated through morphological techniques in light microscopy, confocal scanning laser microscopy and transmission electron microscopy, so that the possible relation between neem action and further impairment in these ectoparasites feed performance could be established. Neem oil demonstrated a clear dose-dependent effect in the analyzed samples. The agranular (type I) and granular acini (types II and III) showed, particularly in individuals treated with the highest concentrations of the product, cells with irregular shape, intense cytoplasmic disorganization and vacuolation, dilation of rough endoplasmic reticulum lumen, besides alterations in mitochondrial intermembrane space. These morphological damages may indicate modifications in salivary glands physiology, demonstrating the harmful effects of compounds present in neem oil on ticks. These results reinforce the potential of neem as an alternative method for controlling R. sanguineus ticks, instead of synthetic acaricides.
Kaufman, W Reuben; Flynn, Peter C; Reynolds, Stuart E
The degree of plasticization of the alloscutal cuticle of a 'hard' (ixodid) tick, Amblyomma hebraeum, and a 'soft' (argasid) tick, Ornithodoros moubata, was assessed throughout the blood-feeding period. Cuticle viscosity was calculated from rate of creep of cuticle under constant load using a Maxwell model. Feeding-related plasticization (i.e. increased rate of extension under a constant load) occurred in A. hebraeum but not in O. moubata. Maxwell viscosity of unfed A. hebraeum cuticle was relatively high (approximately 720 GPa s) but was significantly lower in feeding ticks. Small partially fed ticks displayed a viscosity of approximately 108 GPa s. Still lower values (42 GPa s) were observed in the largest of the engorged ticks. Following cessation of feeding, there was a significant but limited reversal in viscosity back to approximately 100 GPa s. The water content of cuticle of unfed A. hebraeum (23.4% of wet mass) rose sharply after the onset of feeding and reached a plateau value of 34.0% at a fed/unfed weight ratio of 3 and beyond. Ixodid ticks lay down new endocuticle during the feeding period. The observed increase in cuticle hydration suggests that both old and new cuticles are hydrated during feeding. Monoamines may play an important role in controlling cuticle viscosity. Dopamine (DA) injected into partially fed A. hebraeum caused plasticization. 5-Hydroxytryptamine (serotonin, 5-HT), which induces plasticization in the blood-sucking insect Rhodnius prolixus, had no statistically significant effect on tick cuticle. Octopamine (OA) and tyramine both caused cuticle stiffening (i.e. opposed plasticization). This suggests a possible inhibitory effect but co-injection of OA with DA did not reduce DA-induced plasticization. The mechanism leading to plasticization of tick cuticle may involve a change in cuticular pH. The viscosity of tick cuticle loops was highest at pH 8.0 (389 GPa s) and fell precipitously in the acidic range to a low value of 2.2 GPa s at pH 5.5-5.7. A cuticular pH of approximately 6.5 would account for the lowest viscosity observed under physiological conditions (42.4 GPa s for large, day 0, engorged ticks). The V-ATPase inhibitor, concanamycin A, was a potent inhibitor of DA-induced plasticization. These results are consistent with a model in which DA acts to cause plasticization through transport of H(+) ions into the cuticle. Measurement of cuticular ion (Na(+), K(+), Ca(2+), Mg(2+)) content did not suggest that plasticization is caused by any of these ions. Taken together, our results suggest that the mechanism of cuticular plasticization in feeding A. hebraeum is related to hydration, and involves the transport of H(+) ions into the sub-cuticular space by cells in the hypodermis. Feeding-induced plasticization was not observed in the rapid feeding tick, O. moubata.
de la Fuente, José; Manzano-Roman, Raúl; Naranjo, Victoria; Kocan, Katherine M; Zivkovic, Zorica; Blouin, Edmour F; Canales, Mario; Almazán, Consuelo; Galindo, Ruth C; Step, Douglas L; Villar, Margarita
The lone star tick, Amblyomma americanum, vectors pathogens of emerging diseases of humans and animals in the United States. Currently, measures are not available for effective control of A. americanum infestations. Development of vaccines directed against tick proteins may reduce tick infestations and the transmission of tick-borne pathogens. However, the limiting step in tick vaccine development has been the identification of tick protective antigens. Herein, we report the application of RNA interference (RNAi) for screening an A. americanum cDNA library for discovery of tick protective antigens that reduce tick survival and weights after feeding. Four cDNA clones, encoding for putative threonyl-tRNA synthetase (2C9), 60S ribosomal proteins L13a (2D10) and L13e (2B7), and interphase cytoplasm foci protein 45 (2G7), were selected for vaccine studies in cattle, along with subolesin, a tick protective protein identified previously. In vaccinated cattle, an overall efficacy (E)>30% was obtained when considering the vaccine effect on both nymphs and adults, but only 2D10, 2G7 and subolesin affected both tick stages. The highest efficacy of control for adult ticks (E>55%) was obtained in cattle vaccinated with recombinant 2G7 or subolesin. These collective results demonstrated the feasibility of developing vaccines for the control of lone star tick infestations. The use of RNAi for identification of tick protective antigens proved to be a rapid and cost-effective tool for discovery of candidate vaccine antigens, and this approach could likely be applied to other parasites of veterinary and medical importance.
Kim, Tae K.; Radulovic, Zeljko; Mulenga, Albert
Amblyomma americanum tick serine protease inhibitor (serpin, AAS) 19, is a highly conserved protein that is characterized by its functional domain being 100% conserved across tick species. We also reported that AAS19 was an immunogenic tick saliva protein with anti-haemostatic functions and an inhibitor of trypsin-like proteases including five of the eight serine protease factors in the blood clotting cascade. In this study the goal was to validate the importance of AAS19 in A. americanum tick physiology, assess immunogenicity and investigate tick vaccine efficacy of yeast-expressed recombinant (r) AAS19. We confirm that AAS19 is important to A. americanum fitness and blood meal feeding. AAS19 mRNA disruption by RNAi silencing caused ticks to obtain blood meals that were 50% smaller than controls, and treated ticks being morphologically deformed with 100% of the deformed ticks dying in incubation. We show that rAAS19 is highly immunogenic in that two 500 µg inoculations mixed with TiterMax Gold adjuvant provoked antibody titers of more than 1:320000 that specifically reacted with native AAS19 in unfed and partially fed tick tissue. Since AAS19 is injected into animals during tick feeding, we challenge infested immunized rabbits twice to test if tick infestations of immunized rabbits could act as booster. While in the first infestation significantly smaller tick blood meals were observed on one of the two immunized rabbits, smaller blood meals were observed on both rabbits, but 60% of ticks that engorged on immunized rabbits in the second infestation failed to lay eggs. It is notable that ticks fed faster on immunized animals despite obtaining smaller blood meals. We conclude that rAAS19 is a potential component of cocktail tick vaccine. PMID:26746129
Kim, Tae K; Radulovic, Zeljko; Mulenga, Albert
Amblyomma americanum tick serine protease inhibitor (serpin, AAS) 19, is a highly conserved protein that is characterized by its functional domain being 100% conserved across tick species. We also reported that AAS19 was an immunogenic tick saliva protein with anti-haemostatic functions and an inhibitor of trypsin-like proteases including five of the eight serine protease factors in the blood clotting cascade. In this study the goal was to validate the importance of AAS19 in A. americanum tick physiology, assess immunogenicity and investigate tick vaccine efficacy of yeast-expressed recombinant (r) AAS19. We confirm that AAS19 is important to A. americanum fitness and blood meal feeding. AAS19 mRNA disruption by RNAi silencing caused ticks to obtain blood meals that were 50% smaller than controls, and treated ticks being morphologically deformed with 100% of the deformed ticks dying in incubation. We show that rAAS19 is highly immunogenic in that two 500 μg inoculations mixed with TiterMax Gold adjuvant provoked antibody titers of more than 1:320,000 that specifically reacted with native AAS19 in unfed and partially fed tick tissue. Since AAS19 is injected into animals during tick feeding, we challenge infested immunized rabbits twice to test if tick infestations of immunized rabbits could act as booster. While in the first infestation significantly smaller tick blood meals were observed on one of the two immunized rabbits, smaller blood meals were observed on both rabbits, but 60% of ticks that engorged on immunized rabbits in the second infestation failed to lay eggs. It is notable that ticks fed faster on immunized animals despite obtaining smaller blood meals. We conclude that rAAS19 is a potential component of cocktail tick vaccine.
Crump, D; Silverstein, R M; Williams, H J; Fitzgerald, T D
Previous studies have shown that larvae of the eastern tent caterpillar (Malacosoma americanum F.) mark trails, leading from their tent to feeding sites on host trees, with a pheromone secreted from the posterior tip of the abdominal sternum. 5β-Cholestane-3,24-dione (1) has been identified as an active component of the trail. The larvae have a threshold sensitivity to the pheromone of 10(-11) g/mm of trail. Several related compounds elicit the trail-following response. Two other species of tent caterpillars also responded positively to the pheromone in preliminary laboratory tests.
Trout Fryxell, R. T.; DeBruyn, J. M.
The Lone Star tick, Amblyomma americanum, transmits several bacterial pathogens including species of Anaplasma and Ehrlichia. Amblyomma americanum also hosts a number of non-pathogenic bacterial endosymbionts. Recent studies of other arthropod and insect vectors have documented that commensal microflora can influence transmission of vector-borne pathogens; however, little is known about tick microbiomes and their possible influence on tick-borne diseases. Our objective was to compare bacterial communities associated with A. americanum, comparing Anaplasma/Ehrlichia -infected and uninfected ticks. Field-collected questing specimens (n = 50) were used in the analyses, of which 17 were identified as Anaplasma/Ehrlichia infected based on PCR amplification and sequencing of groEL genes. Bacterial communities from each specimen were characterized using Illumina sequencing of 16S rRNA gene amplicon libraries. There was a broad range in diversity between samples, with inverse Simpson’s Diversity indices ranging from 1.28–89.5. There were no statistical differences in the overall microbial community structure between PCR diagnosed Anaplasma/Ehrlichia-positive and negative ticks, but there were differences based on collection method (P < 0.05), collection site (P < 0.05), and sex (P < 0.1) suggesting that environmental factors may structure A. americanum microbiomes. Interestingly, there was not always agreement between Illumina sequencing and PCR diagnostics: Ehrlichia was identified in 16S rRNA gene libraries from three PCR-negative specimens; conversely, Ehrlichia was not found in libraries of six PCR-positive ticks. Illumina sequencing also helped identify co-infections, for example, one specimen had both Ehrlichia and Anaplasma. Other taxa of interest in these specimens included Coxiella, Borrelia, and Rickettsia. Identification of bacterial community differences between specimens of a single tick species from a single geographical site indicates that intra
Zhan, Xiangqiang; Yang, Lan; Wang, Dong; Zhu, Jian Kang; Lang, Zhaobo
Ocimum americanum var. pilosum is a chilling-sensitive, widely distributed plant that is consumed as a vegetable in central and southern China. To increase our understanding of cold stress responses in this species, we performed de novo transcriptome assembly for O. americanum var. pilosum and compared the transcriptomes of plants grown under normal and low temperatures. A total of 115,022,842 high quality, clean reads were obtained from four libraries (two replicates of control samples and two replicates of chilling-treated samples) and were used to perform de novo transcriptome assembly. After isoforms were considered, 42,816 unigenes were generated, 30,748 of which were similar to known proteins as determined by a BLASTx search (E-value < =1.0E-05) against NCBI non-redundant, Swiss-Prot, Gene Ontology, KEGG, and Cluster of COG databases. Comparative analysis of transcriptomes revealed that 5179 unigenes were differentially expressed (with at least 2-fold changes, FDR < 0.01) in chilling-treated samples, and that 2344 and 2835 unigenes were up- and down-regulated by chilling stress, respectively. Expression of the 10 most up-regulated and the five most down-regulated unigenes was validated by qRT-PCR. To increase our understanding of these differentially expressed unigenes, we performed Gene ontology and KEGG pathway enrichment analyses. The CBF-mediated transcriptional cascade, a well-known cold tolerance pathway, was reconstructed using our de novo assembled transcriptome. Our study has generated a genome-wide transcript profile of O. americanum var. pilosum and a de novo assembled transcriptome, which can be used to characterize genes related to diverse biological processes. This is the first study to assess the cold-responsive transcriptome in an Ocimum species. Our results suggest that cold temperature significantly affects genes related to protein translation and cellular metabolism in this chilling sensitive species. Although most of the CBF
Nchu, Felix; Magano, Solomon R; Eloff, Jacobus N
Dichloromethane (DCM) extract of garlic (Allium sativum Linn.) bulbs was assessed for its repellent effect against the hard tick, Hyalomma rufipes (Acari: Ixodidae) using two tick behavioural bioassays; Type A and Type B repellency bioassays, under laboratory conditions. These bioassays exploit the questing behaviour of H. rufipes, a tick that in nature displays ambush strategy, seeking its host by climbing up on vegetation and attaching to a passing host. One hundred microlitres (100 µL) of the test solution containing DCM extract of garlic bulbs and DCM at concentrations of 0.35%, 0.7% or 1.4% w/v were evaluated. DCM only was used for control. Tick repellency increased significantly (R2 = 0.98) with increasing concentration (40.03% - 86.96%) yielding an EC50 of 0.45% w/v in Type B repellency bioassay. At concentration of 1.4% w/v, the DCM extract of garlic bulbs produced high repellency index of 87% (male ticks) and 87.5% (female ticks) in the Type A repellency bioassay. Only 4% avoidance of male ticks or female ticks was recorded in the Type B repellency bioassay. In the corresponding controls, the mean numbers of non-repelled male or female ticks were 80% and 41 males or 38 females of 50 ticks in the Type A and Type B repellency bioassays, respectively. The variations in the results could be attributed to the difference in tick repellent behaviours that were assessed by the two repellency bioassays; the Type A repellency bioassay assessed repellent effect of garlic extracts without discriminating between deterrence and avoidance whereas the Type B repellency bioassay only assessed avoidance response. Generally, DCM extract of garlic was repellent against H. rufipes, albeit weak tick repellency was obtained in the Type B repellency bioassay. Furthermore, this study established that the tick repellent activity of garlic extracts is predominantly by deterrence.
Carroll, J F; Benante, J P; Klun, J A; White, C E; Debboun, M; Pound, J M; Dheranetra, W
The repellent efficacies of the U.S. military repellent 33% N,N-diethyl-3-methylbenzamide (deet), 10% and 20% (1S, 2'S) 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) and 10% and 20% 1-methyl-propyl-2-(hydroxyethyl)-1-piperidinecarboxylate (Bayrepel) cream formulations on human volunteers against the lone star tick Amblyomma americanum (L.) were evaluated in a simulated forest floor environment over a 12-h testing period. At 2-h intervals, volunteers, with repellent applied in a 5-cm-wide band around each ankle, stood for 5 min in plastic tubs containing leaf litter and 100 host-seeking A. americanum nymphs. Ticks were allowed to remain on a volunteer's feet and ankles for an additional 5 min after the volunteer exited the tub. All repellent formulations provided high levels of protection for the entire 12 h. No ticks crossed 5-cm-wide bands of 20% SS220 and Bayrepel during any challenge, and thus 100% protection was afforded throughout the test. These formulations showed a long-lasting efficacy hitherto unknown in tick repellents intended for use on human skin.
Klyachko, Olga; Stein, Barry D; Grindle, Nathan; Clay, Keith; Fuqua, Clay
A Coxiella-type microbe occurs at 100% frequency in all Amblyomma americanum ticks thus far tested. Using laboratory-reared ticks free of other microbes, we identified the Amblyomma-associated Coxiella microbe in several types of tissue and at various stages of the life cycle of A. americanum by 16S rRNA gene sequencing and diagnostic PCR. We visualized Amblyomma-associated Coxiella through the use of a diagnostic fluorescence in situ hybridization (FISH) assay supplemented with PCR-based detection, nucleic acid fluorescent staining, wide-field epifluorescence and confocal microscopy, and transmission electron microscopy (TEM). Specific fluorescent foci were observed in several tick tissues, including the midgut and the Malpighian tubules, but particularly bright signals were observed in the granular acini of salivary gland clusters and in both small and large oocytes. TEM confirmed intracellular bacterial structures in the same tissues. The presence of Amblyomma-associated Coxiella within oocytes is consistent with the vertical transmission of these endosymbionts. Further, the presence of the Amblyomma-associated Coxiella symbiont in other tissues such as salivary glands could potentially lead to interactions with horizontally acquired pathogens.
Mixson, Tonya R; Lydy, Shari L; Dasch, Gregory A; Real, Leslie A
A hierarchial population genetic study was conducted on 703 individual Amblyomma americanum from nine populations in Georgia, U.S.A. Populations were sampled from the Coastal Plain, midland Piedmont region, and the upper Piedmont region. Twenty-nine distinct haplotypes were found. A minimum spanning tree was constructed that indicated these haplotypes comprised two lineages, the root of which was distinctly star-like. The majority of the variation found was among ticks within each population, indicating high amounts of gene flow and little genetic differentiation between the three regions. An overall F(ST) value of 0.006 supported the lack of genetic structuring between collection sites in Georgia. Mantel regression analysis revealed no isolation by distance. Signatures of population expansion were detected in the shapes of the mismatch distribution and tests of neutrality. The absence of genetic differentiation combined with the rejection of the null model of isolation by distance may indicate recent range expansion in Georgia or insufficient time to reach an equilibrium where genetic drift may have affected allele frequencies. Alternatively, the high degree of panmixia found within A. americanum in Georgia may be due to bird-mediated dispersal of ticks increasing the genetic similarity between geographically separated populations.
Scott Dahlgren, F.; Paddock, Christopher D.; Springer, Yuri P.; Eisen, Rebecca J.; Behravesh, Casey Barton
Spotted fever group (SFG) Rickettsia species are etiologic agents of a wide range of human infections from asymptomatic or mild infections to severe, life-threatening disease. In the United States, recent passive surveillance for SFG rickettsiosis shows an increased incidence and decreased severity of reported cases. The reasons for this are not well understood; however, we hypothesize that less pathogenic rickettsiae are causing more human infections, while the incidence of disease caused by more pathogenic rickettsiae, particularly Rickettsia rickettsii, is relatively stable. During the same period, the range of Amblyomma americanum has expanded. Amblyomma americanum is frequently infected with Candidatus Rickettsia amblyommii, a SFG Rickettsia of unknown pathogenicity. We tested our hypothesis by modeling incidence rates from 1993 to 2013, hospitalization rates from 1981 to 2013, and case fatality rates from 1981 to 2013 regressed against the presence of A. americanum, the decade of onset of symptoms, and the county of residence. Our results support the hypothesis, and we show that the expanding range of A. americanum is associated with changes in epidemiology reported through passive surveillance. We believe epidemiological and acarological data collected on individual cases from enhanced surveillance may further elucidate the reasons for the changing epidemiology of SFG rickettsiosis. PMID:26503270
The lone star tick, Amblyomma americanum, is one of important Ixodid tick species that are known ectoparasites and disease vectors affecting animal and human health in the United States. New pesticides or repellents with novel mode of action would help control resistant ticks and protect humans from...
Jiang, Zhao; Ma, Bingbing; Erinle, Kehinde Olajide; Cao, Bo; Liu, Xiaoxue; Ye, Siyuan; Zhang, Ying
Plants belonging to the genus Pennisetum have been reported to be resistant to atrazine, a widely used herbicide that also can cause serious pollution of soil and water. To evaluate the enzymatic antioxidant defense mechanism to the oxidative stress of atrazine, experiments focusing on the malondialdehyde (MDA) content and antioxidant enzyme in the leaf and root of Pennisetum americanum (L.) K. Schum (P. americanum) during long-term (68days) atrazine exposure were carried out. The test plant had not suffered obvious lipid membrane peroxidation, which was further confirmed by the result that the MDA content in the root and the leaf of the test plant did not significantly increase when treated with various concentrations of atrazine. The activity of the well-known antioxidases, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD), was increased when the plants were exposed to atrazine, especially at moderate concentrations (20mgkg(-1) or below). These results revealed that antioxidant enzymes played important roles in protecting P. americanum from the oxidative damage induced by atrazine. The increased and more stable SOD activity in the leaf compared to in the root portion of the plant under increasing atrazine concentrations and increasing exposure time indicated that the leaf exhibited more pronounced superoxide radical scavenging ability than the root. Furthermore, correlation analysis showed that the studied antioxidases were positively correlated with the exposure time, suggesting that the antioxidant defense in P. americanum seedlings might become stronger as the plant matures. In conclusion, the increasing antioxidant enzyme activities enable P. americanum seedlings to cope with the oxidative stress induced by moderate concentrations (20mgkg(-1) or below) of atrazine. Copyright © 2016 Elsevier B.V. All rights reserved.
Harmon, Jessica R; Scott, M Cathy; Baker, Ellen M; Jones, Carl J; Hickling, Graham J
The current status of tick-borne diseases in the southeastern United States is challenging to define due to emerging pathogens, uncertain tick/host relationships, and changing disease case definitions. A golf-oriented retirement community on the Cumberland Plateau in Tennessee experienced an ehrlichiosis outbreak in 1993, prompting efforts to reduce the local tick population using '4-Poster' acaricide devices targeting white-tailed deer (Odocoileus virginianus). In 2009, the prevalence of Ehrlichia spp. in questing ticks was surveyed in the area and compared to a Tennessee state park where acaricide had not been applied. The range of wildlife hosts that immature Amblyomma americanum fed upon and the role that these hosts may play in pathogen dynamics were investigated using a reverse line blot (RLB) bloodmeal analysis technique. Amblyomma americanum was by far the most common tick species in both study areas (>99% of ticks collected). Of 303 adult and nymphal A. americanum tested at the retirement community, six were positive for Ehrlichia chaffeensis (2.0%), 16 were positive for E. ewingii (5.3%), and six were positive for Panola Mountain Ehrlichia (2.0%). This is the first confirmation of Panola Mountain Ehrlichia in A. americanum from the state of Tennessee. The 9.3% prevalence of Ehrlichia spp. in ticks from the retirement community was similar to that detected at the state park site (5.5%), suggesting that the 4-Poster treatment had not been sufficient to reduce Ehrlichia spp. cycling in the tick population. At both study sites, A. americanum fed on a wide range of mammal and bird species, with a minority of detectable bloodmeals coming from deer. Of the Ehrlichia-infected nymphs with positive bloodmeal identification, none fed on deer, indicating that multiple vertebrate species are contributing to sylvatic maintenance of Ehrlichia spp. at these sites. This highlights the difficulty of attempting to reduce the risk of tick-borne disease through host
Bior, Abdelaziz D; Essenberg, Richard C; Sauer, John R
Genes expressed differentially in the salivary glands of unfed and fed male ticks, Amblyomma americanum (L.), were identified, cloned and sequenced, and some were compared with those expressed in the salivary glands of Dermacentor andersoni. Total protein and RNA increased sixfold in the salivary glands of fed male A. americanum, while in fed male D. andersoni salivary glands, RNA increased approximately 3.5 times. Feeding D. andersoni in the presence of females increased total RNA by 25% over those fed in the absence of females. Complementary DNAs were synthesized from RNA obtained from unfed and fed ticks and amplified using RNA arbitrarily primed polymerase chain reaction (RAP-PCR) with three different primers in separate reactions. Differential display showed clear banding differences between the fed and the unfed ticks in A. americanum and D. andersoni. Sixty-one cDNA fragments that appeared to be from differentially expressed genes in A. americanum were isolated, cloned and sequenced. Hybridization reactions with labeled cDNA probes confirmed the differential expression of many of the genes in unfed and fed ticks' salivary glands; however, many of the bands contained more than one fragment and some of the fragments isolated from apparently differential bands were not specific. Sequences for 28 of the cDNA fragments (150-600 nucleotides in length) demonstrated similarity to genes in the databases, but nine of these were similar to sequences of unknown function. Some of the gene fragments identified may be important to tick feeding or tick salivary gland physiology, including a histamine-binding protein, an organic ion transporter, an apoptosis inhibitor, a cathepsin-B-like cysteine protease, proteins involved in gene regulation and several proteins involved in protein synthesis. Cross-hybridization of identified cDNAs from A. americanum with cDNA probes synthesized from D. andersoni total RNA did not show significant similarity between the two species.
Testo, Weston L; Watkins, James E
Understanding the ecology of rare species can inform aspects of conservation strategies; however, the mechanisms of rarity remain elusive for most pteridophytes, which possess independent and ecologically distinct gametophyte and sporophyte generations. To elucidate factors contributing to recent declines of the rare fern Asplenium scolopendrium var. americanum, we studied the ecology and ecophysiology of its gametophyte generation, focusing on responses to competition, temperature, and water stress. Gametophytes of A. scolopendrium var. americanum, its widespread European relative A. scolopendrium var. scolopendrium, and five co-occurring fern species were grown from spores. Gametophytes were grown at 20°C and 25°C, and germination rates, intra- and interspecific competition, desiccation tolerance, and sporophyte production were determined for all species. Gametophytes of A. scolopendrium var. americanum had the lowest rates of germination and sporophyte production among all species studied and exhibited the greatest sensitivity to interspecific competition, temperature increases, and desiccation. Mature gametophytes of A. scolopendrium var. americanum grown at 25°C were 84.6% smaller than those grown at 20°C, and only 1.5% produced sporophytes after 200 d in culture. Similar responses were not observed in other species studied. The recent declines and current status of populations of A. scolopendrium var. americanum are linked to its gametophyte's limited capacity to tolerate competition and physiological stress linked to climate change. This is the first study to develop a mechanistic understanding of rarity and decline in a fern and demonstrates the importance of considering the ecology of the gametophyte in plants with independent sporophyte and gametophyte generations.
Zasada, Inga A.; Peetz, Amy; Howe, Dana K.; Wilhelm, Larry J.; Cheam, Daravuth; Denver, Dee R.; Smythe, Ashleigh B.
Nematodes within the Xiphinema americanum species complex are economically important because they vector nepoviruses which cause considerable damage to a variety of agricultural crops. The taxonomy of X. americanum species complex is controversial, with the number of putative species being the subject of debate. Accurate phylogenetic knowledge of this group is highly desirable as it may ultimately reveal genetic differences between species. For this study, nematodes belonging to the X. americanum species complex, including potentially mixed species populations, were collected from 12 geographically disparate locations across the U.S. from different crops and in varying association with nepoviruses. At least four individuals from each population were analyzed. A portion of the 18S nuclear ribosomal DNA (rDNA) gene was sequenced for all individuals while the internal transcribed spacer region 1 (ITS1) of rDNA was cloned and 2 to 6 clones per individual were sequenced. Mitochondrial genomes for numerous individuals were sequenced in parallel using high-throughput DNA sequencing (HTS) technology. Phylogenetic analysis of the 18S rDNA revealed virtually identical sequences across all populations. Analysis of ITS1 rDNA sequences revealed several well-supported clades, with some degree of congruence with geographic location and viral transmission, but also numerous presumably paralogous sequences that failed to form clades with other sequences from the same population. Analysis of mitochondrial DNA (mtDNA) indicated the presence of three distinct monophyletic clades of X. americanum species complex nematodes. Two clades contained nematodes found in association with nepovirus and the third contained divergent mtDNA sequences from three nematode populations from the western U.S. where nepovirus was absent. The inherent heterogeneity in ITS1 rDNA sequence data and lack of informative sites in 18S rDNA analysis suggests that mtDNA may be more useful in sorting out the
Osperalycus tenerphagus, a new genus and species of Nematalycidae (Acari: Endeostigmata), is described from Ohio, USA, using light microscopy and low temperature scanning electron microscopy. Specimens were extracted from two different loam soils. This genus can be readily distinguished from the oth...
Ermilov, Sergey G.
Abstract A species list of identified oribatid mite taxa (Acari, Oribatida) in the fauna of Vietnam is provided. During 1967–2015, a total of 535 species/subspecies from 222 genera and 81 families was registered. Of these, 194 species/subspecies were described as new for science from Vietnam. PMID:26798306
Fritzen, Charissa M.; Huang, Junjun; Westby, Kathleen; Freye, James D.; Dunlap, Brett; Yabsley, Michael J.; Schardein, Mike; Dunn, John R.; Jones, Timothy F.; Moncayo, Abelardo C.
Rocky Mountain spotted fever, Lyme disease, and ehrlichiosis are tick-borne diseases that are reported annually in Kentucky. We conducted a survey to describe infection prevalence of tick-borne pathogens in Amblyomma americanum and Dermacentor variabilis ticks collected in Kentucky. During 2007–2008, we collected 287 ticks (179 D. variabilis and 108 A. americanum) from canine, feral hog, horse, raccoon, white-tailed deer, and human hosts in six counties in Kentucky. Ticks were screened for Rickettsia spp., Borrelia spp., and Ehrlichia spp. by using polymerase chain reaction. Forty-one (14.3%) ticks (31 A. americanum and 10 D. variabilis) were polymerase chain reaction–positive for a Rickettsia spp. Fourteen (4.9%) ticks (6 A. americanum and 8 D. variabilis) were positive for E. chaffeensis, and 4 A. americanum (1.4%) were positive for E. ewingii. One (0.4%) A. americanum was positive for Borrelia lonestari. Although Rocky Mountain spotted fever is diagnosed in Kentucky, no R. rickettsii was found in ticks in this study. PMID:21976578
Fritzen, Charissa M; Huang, Junjun; Westby, Kathleen; Freye, James D; Dunlap, Brett; Yabsley, Michael J; Schardein, Mike; Dunn, John R; Jones, Timothy F; Moncayo, Abelardo C
Rocky Mountain spotted fever, Lyme disease, and ehrlichiosis are tick-borne diseases that are reported annually in Kentucky. We conducted a survey to describe infection prevalence of tick-borne pathogens in Amblyomma americanum and Dermacentor variabilis ticks collected in Kentucky. During 2007-2008, we collected 287 ticks (179 D. variabilis and 108 A. americanum) from canine, feral hog, horse, raccoon, white-tailed deer, and human hosts in six counties in Kentucky. Ticks were screened for Rickettsia spp., Borrelia spp., and Ehrlichia spp. by using polymerase chain reaction. Forty-one (14.3%) ticks (31 A. americanum and 10 D. variabilis) were polymerase chain reaction-positive for a Rickettsia spp. Fourteen (4.9%) ticks (6 A. americanum and 8 D. variabilis) were positive for E. chaffeensis, and 4 A. americanum (1.4%) were positive for E. ewingii. One (0.4%) A. americanum was positive for Borrelia lonestari. Although Rocky Mountain spotted fever is diagnosed in Kentucky, no R. rickettsii was found in ticks in this study.
Monzón, Javier D.; Atkinson, Elizabeth G.; Henn, Brenna M.; Benach, Jorge L.
The lone star tick, Amblyomma americanum, is an important disease vector and the most frequent tick found attached to humans in the eastern United States. The lone star tick has recently experienced a rapid range expansion into the Northeast and Midwest, but despite this emerging infectious threat to wildlife, livestock, and human health, little is known about the genetic causes and consequences of the geographic expansion. In the first population genomic analysis of any tick species, we characterize the genetic diversity and population structure of A. americanum across its current geographic range, which has recently expanded. Using a high-throughput genotyping-by-sequencing approach, we discovered more than 8,000 single nucleotide polymorphisms in 90 ticks from five locations. Surprisingly, newly established populations in New York (NY) and Oklahoma (OK) are as diverse as historic range populations in North and South Carolina. However, substantial population structure occurs among regions, such that new populations in NY and OK are genetically distinct from historic range populations and from one another. Ticks from a laboratory colony are genetically distinct from wild populations, underscoring the need to account for natural variation when conducting transmission or immunological studies, many of which utilize laboratory-reared ticks. An FST-outlier analysis comparing a recently established population to a long-standing population detected numerous outlier sites, compatible with positive and balancing selection, highlighting the potential for adaptation during the range expansion. This study provides a framework for applying high-throughput DNA sequencing technologies for future investigations of ticks, which are common vectors of diseases. PMID:27190204
Williams-Newkirk, Amanda Jo; Rowe, Lori A.; Mixson-Hayden, Tonya R.; Dasch, Gregory A.
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
Sayler, Katherine A; Wamsley, Heather L; Pate, Melanie; Barbet, Anthony F; Alleman, A Rick
Rickettsia amblyommii is a bacterium in the spotted fever group of organisms associated with the lone star tick (LST), Amblyomma americanum. The LST is the most commonly reported tick to parasitize humans in the southeastern US. Within this geographic region, there have been suspected cases of Rocky Mountain spotted fever (RMSF) where the causative agent, R. rickettsii, was not identified in the local tick population. In these areas, patients with clinical signs of RMSF had low or no detectable antibodies to R. rickettsii, resulting in an inability to confirm a diagnosis. R. amblyommii was cultivated from host-seeking LSTs trapped in Central Florida and propagated in ISE6 (Ixodes scapularis) and AAE2 (A. americanum) cells. Quantitative PCR targeting the 17-kD gene of Rickettsia spp. identified the genus of the organism in culture. Variable regions of groEL, gtlA and rompA genes were amplified and sequenced to confirm the species. The prevalence of R. amblyommii in LSTs within the geographic region was determined by qPCR followed by conventional PCR and direct sequencing. Analyses of amplified sequences from the cultured organism were 100% homologous to R. amblyommii. The overall prevalence of Rickettsia spp. in the local population of LSTs was 57.1% and rompA sequence analysis identified only R. amblyommii in LSTs. A Florida strain of R. amblyommii was successfully cultivated in two tick cell lines. Further evaluation of the new strain and comparisons to the other geographic strains is needed. The prevalence of this SFG organism in the tick population warrants further investigation into the organism's ability to cause clinical disease in mammalian species.
Williams-Newkirk, Amanda Jo; Rowe, Lori A; Mixson-Hayden, Tonya R; Dasch, Gregory A
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
Monzón, Javier D; Atkinson, Elizabeth G; Henn, Brenna M; Benach, Jorge L
The lone star tick, Amblyomma americanum, is an important disease vector and the most frequent tick found attached to humans in the eastern United States. The lone star tick has recently experienced a rapid range expansion into the Northeast and Midwest, but despite this emerging infectious threat to wildlife, livestock, and human health, little is known about the genetic causes and consequences of the geographic expansion. In the first population genomic analysis of any tick species, we characterize the genetic diversity and population structure of A. americanum across its current geographic range, which has recently expanded. Using a high-throughput genotyping-by-sequencing approach, we discovered more than 8,000 single nucleotide polymorphisms in 90 ticks from five locations. Surprisingly, newly established populations in New York (NY) and Oklahoma (OK) are as diverse as historic range populations in North and South Carolina. However, substantial population structure occurs among regions, such that new populations in NY and OK are genetically distinct from historic range populations and from one another. Ticks from a laboratory colony are genetically distinct from wild populations, underscoring the need to account for natural variation when conducting transmission or immunological studies, many of which utilize laboratory-reared ticks. An FST-outlier analysis comparing a recently established population to a long-standing population detected numerous outlier sites, compatible with positive and balancing selection, highlighting the potential for adaptation during the range expansion. This study provides a framework for applying high-throughput DNA sequencing technologies for future investigations of ticks, which are common vectors of diseases.
Mixson, T.R.; Ginsberg, H.S.; Campbell, S.R.; Sumner, J.W.; Paddock, C.D.
The lone star tick, Amblyomma americanum (L.), has increased in abundance in several regions of the northeastern United States, including areas of Long Island, NY. Adult and nymphal stage A. americanum collected from several sites on Long Island were evaluated for infection with Ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (HME), by using a nested polymerase chain reaction assay. Fifty-nine (12.5%) of ,17.3 adults and eight of 11.3 pools of five nymphs each (estimated minimum prevalence of infection 1.4%) contained DNA of E. chaffeensis. These data, coupled with the documented expansion of lone star tick populations in the northeastern United States, confirm that E. chaffeensis is endemic to many areas of Long Island and that HME should be considered among the differential diagnoses of the many distinct tick-borne diseases that occur in this region.
George, J E; Osburn, R L; Wikel, S K
Purebred and crossbred Bos indicus calves were infested 1, 2, or 3 times with 10 female and 5 male Amblyomma americanum. Resistance was acquired by both the purebred and the crossbred calves after 1 infestation and resulted in statistically significant decreases in the percentages of females that engorged, the mean weights of engorged females, and the mean weights of egg masses. Comparisons between breeds of the percent of female ticks that engorged during the first and second infestations indicate that purebred B. indicus expressed a stronger acquired resistance to A. americanum more readily than did crossbred animals. However, calves of both genetic compositions displayed similar levels of resistance during a third exposure. All tick-exposed and control animals were skin tested with salivary gland extracts of A. americanum, A. cajennense and Dermacentor andersoni. Control, uninfested calves, did not display significant cutaneous reactivity to these extracts. All calves that had been infested had immediate, 30-min, 5-hr and delayed, 24-hr, skin reactions to Amblyomma species antigens. Reactions to D. andersoni salivary antigens in tests of both purebred and crossbred calves with acquired resistance to A. americanum suggest that Amblyomma species salivary gland antigens might have cross reactive moieties with a salivary extract prepared from D. andersoni. Peripheral blood lymphocyte in vitro responsiveness to Amblyomma species antigens was detected in purebred calves after a first, second, and third infestation, indicating the presence of cells of the immune system capable of recognizing and undergoing blast transformation in response to tick salivary components.(ABSTRACT TRUNCATED AT 250 WORDS)
Williams-Newkirk, Amanda Jo; Rowe, Lori A; Mixson-Hayden, Tonya R; Dasch, Gregory A
We used next generation sequencing to detect the bacterium "Candidatus Midichloria mitochondrii" for the first time in lone star ticks (Amblyomma americanum) from the eastern United States. 177 individuals and 11 tick pools from seven sites in four states were tested by pyrosequencing with barcoded 16S rRNA gene eubacterial primers targeting variable regions 5-3. Average infection prevalence was 0.15 across all surveyed populations (range 0-0.29) and only the site with the smallest sample size (n = 5) was negative. Three genotypes differing by 2.6-4.1 % in a 271 bp region of 16S rRNA gene were identified. Two variants co-occurred in sites in North Carolina and New York, but were not observed in the same tick at those sites. The third genotype was found only in Georgia. Phylogenetic analysis of this fragment indicated that the three variants are more closely related to "Candidatus Midichloria mitochondrii" genotypes from other tick species than to each other. This variation suggests that multiple independent introductions occurred in A. americanum which may provide insight into bacterial spread within its ecosystem and parasitism on this tick. Whether the presence of this bacterium affects acquisition or maintenance of other pathogens and symbionts in A. americanum or the survival, biology and evolution of the tick itself is unknown.
Zhang, Xing; Norris, Douglas E; Rasgon, Jason L
The lone star tick Amblyomma americanum is host to a wide diversity of endosymbiotic bacteria. We identified a novel Wolbachia symbiont infecting A. americanum. Multilocus sequence typing phylogenetically placed the endosymbiont in the increasingly div