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Sample records for carry flea-borne rickettsia

  1. [Probable case of flea-borne spotted fever (Rickettsia felis)].

    PubMed

    Faccini-Martínez, Álvaro A; Forero-Becerra, Elkin G; Cortés-Vecino, Jesús A; Polo-Teran, Luis J; Jácome, Jorge H; Vargas, Jimmy J; Valbuena, Gustavo; Hidalgo, Marylin

    2013-09-01

    Rickettsia felis is the etiologic agent of flea-borne spotted fever, with Ctenocephalides felis as its main vector and reservoir. Typically, the disease presents as acute fever associated with headache, asthenia, generalized maculo-papular rash, and in some cases, an inoculation eschar. In recent years, R. felis has acquired an important role in the etiology of the acute febrile syndrome; it is indeed an emerging infectious disease, albeit underdiagnosed. Indirect immunofluorescence assay (IFA) is currently the reference diagnostic method. However, this technique has limitations related to the cross reactivity among different species of rickettsiae. Herein, we describe a case of a 16 year-old patient with an acute febrile syndrome secondary to probable infection with R. felis. PMID:24652244

  2. Detection of flea-borne Rickettsia species in the Western Himalayan region of India.

    PubMed

    Chahota, R; Thakur, S D; Sharma, M; Mittra, S

    2015-01-01

    Human infections by various rickettsial species are frequently reported globally. We investigated a flea-borne rickettsial outbreak infecting 300 people in Western Himalayan region of India. Arthropod vectors (ticks and fleas) and animal and human blood samples from affected households were analysed by gltA and ompB genes based polymerase chain reaction (PCR). Rat flea (Ceratophyllus fasciatus) samples were found harbouring a Rickettsia sp. Phylogenetic analysis based on gltA gene using PHYLIP revealed that the detected Rickettsia sp. has 100% identity with SE313 and RF2125 strains of Rickettsia sp. of flea origin from Egypt and Thai-Myanmar border, respectively and cf1 and 5 strains from fleas and lice from the USA. But, the nucleotide sequence of genetically variable gene ompB of R14 strain was found closely related to cf9 strain, reported from Ctenocephalides felis fleas. These results highlight the public health importance of such newly discovered or less recognised Rickettsia species/strains, harboured by arthropod vectors like fleas. PMID:26068348

  3. Detection of Rickettsia Species in Fleas Collected from Cats in Regions Endemic and Nonendemic for Flea-Borne Rickettsioses in California.

    PubMed

    Billeter, Sarah A; Diniz, Pedro Paulo Vissotto de Paiva; Jett, Lindsey A; Wournell, Andrea L; Kjemtrup, Anne M; Padgett, Kerry A; Yoshimizu, Melissa Hardstone; Metzger, Marco E; Barr, Margaret C

    2016-03-01

    Rickettsia typhi, transmitted by rat fleas, causes most human flea-borne rickettsioses worldwide. Another rickettsia, Rickettsia felis, found in cat fleas, Ctenocephalides felis, has also been implicated as a potential human pathogen. In the continental United States, human cases of flea-borne rickettsioses are reported primarily from the southern regions of Texas and California where the cat flea is considered the principal vector. In California, more than 90% of locally acquired human cases are reported from suburban communities within Los Angeles and Orange counties despite the almost ubiquitous presence of cat fleas and their hosts throughout the state. The objective of this study is to assess the presence and infection rate of Rickettsia species in cat fleas from selected endemic and nonendemic regions of California. Cat fleas were collected from cats in Los Angeles County (endemic region) and Sacramento and Contra Costa counties (nonendemic region). Sequencing of 17 amplicons confirmed the presence of R. felis in both the endemic and non-endemic regions with a calculated maximum likelihood estimation of 131 and 234 per 1000 fleas, respectively. R. typhi was not detected in any flea pools. Two R. felis-like genotypes were also detected in fleas from Los Angeles County; Genotype 1 was detected in 1 flea pool and Genotype 2 was found in 10 flea pools. Genotype 1 was also detected in a single flea pool from Sacramento County. Results from this study show that R. felis is widespread in cat flea populations in both flea-borne rickettsioses endemic and nonendemic regions of California, suggesting that a high prevalence of this bacterium in cat fleas does not predispose to increased risk of human infection. Further studies are needed to elucidate the role of R. felis and the two R. felis-like organisms as etiologic agents of human flea-borne rickettsioses in California. PMID:26824189

  4. Transmission of flea-borne zoonotic agents.

    PubMed

    Eisen, Rebecca J; Gage, Kenneth L

    2012-01-01

    Flea-borne zoonoses such as plague (Yersinia pestis) and murine typhus (Rickettsia typhi) caused significant numbers of human cases in the past and remain a public health concern. Other flea-borne human pathogens have emerged recently (e.g., Bartonella henselae, Rickettsia felis), and their mechanisms of transmission and impact on human health are not fully understood. Our review focuses on the ecology and epidemiology of the flea-borne bacterial zoonoses mentioned above with an emphasis on recent advancements in our understanding of how these organisms are transmitted by fleas, maintained in zoonotic cycles, and transmitted to humans. Emphasis is given to plague because of the considerable number of studies generated during the first decade of the twenty-first century that arose, in part, because of renewed interest in potential agents of bioterrorism, including Y. pestis. PMID:21888520

  5. Flea-Borne Rickettsioses in the North of Caldas Province, Colombia

    PubMed Central

    Montoya, Viviana; Martínez, Alejandra; Mercado, Marcela; De la Ossa, Alberto; Vélez, Carolina; Estrada, Gloria; Pérez, Jorge E.; Faccini-Martínez, Alvaro A.; Labruna, Marcelo B.; Valbuena, Gustavo

    2013-01-01

    Abstract Rickettsia typhi and R. felis are the etiological agents of murine typhus and flea-borne spotted fever, respectively. Both are emerging acute febrile zoonotic diseases for which fleas are vectors; they also have similar clinical characteristics and global distribution. In 2005, we identified the circulation of murine typhus in 6 towns within the mountainous coffee-growing area north of Caldas, Colombia. We now report the specific seroprevalence against R. typhi and R. felis, and associated risk factors in 7 towns of this province. The combined seroprevalence against the 2 flea-borne rickettsioses is the highest yet reported in the literature: 71.7% (17.8% for R. felis, 25.2% for R. typhi, and 28.7% for both). We also report a prospective analysis of 26 patients with a febrile illness compatible with rickettsioses, including murine typhus; 9 of these patients had a rickettsiosis. This supports our sero-epidemiological results and highlights the diagnostic complexity of febrile syndromes in this region. PMID:23473218

  6. Rickettsial Infections among Ctenocephalides felis and Host Animals during a Flea-Borne Rickettsioses Outbreak in Orange County, California

    PubMed Central

    Fogarty, Carrie; Krueger, Laura; Macaluso, Kevin R.; Odhiambo, Antony; Nguyen, Kiet; Farris, Christina M.; Luce-Fedrow, Alison; Bennett, Stephen; Jiang, Ju; Sun, Sokanary; Cummings, Robert F.; Richards, Allen L.

    2016-01-01

    Due to a resurgence of flea-borne rickettsioses in Orange County, California, we investigated the etiologies of rickettsial infections of Ctenocephalides felis, the predominant fleas species obtained from opossums (Didelphis virginiana) and domestic cats (Felis catus), collected from case exposure sites and other areas in Orange County. In addition, we assessed the prevalence of IgG antibodies against spotted fever group (SFGR) and typhus group (TGR) rickettsiae in opossum sera. Of the 597 flea specimens collected from opossums and cats, 37.2% tested positive for Rickettsia. PCR and sequencing of rickettsial genes obtained from C. felis flea DNA preparations revealed the presence of R. typhi (1.3%), R. felis (28.0%) and R. felis-like organisms (7.5%). Sera from opossums contained TGR-specific (40.84%), but not SFGR-specific antibodies. The detection of R. felis and R. typhi in the C. felis fleas in Orange County highlights the potential risk for human infection with either of these pathogens, and underscores the need for further investigations incorporating specimens from humans, animal hosts, and invertebrate vectors in endemic areas. Such studies will be essential for establishing a link in the ongoing flea-borne rickettsioses outbreaks. PMID:27537367

  7. Rickettsial Infections among Ctenocephalides felis and Host Animals during a Flea-Borne Rickettsioses Outbreak in Orange County, California.

    PubMed

    Maina, Alice N; Fogarty, Carrie; Krueger, Laura; Macaluso, Kevin R; Odhiambo, Antony; Nguyen, Kiet; Farris, Christina M; Luce-Fedrow, Alison; Bennett, Stephen; Jiang, Ju; Sun, Sokanary; Cummings, Robert F; Richards, Allen L

    2016-01-01

    Due to a resurgence of flea-borne rickettsioses in Orange County, California, we investigated the etiologies of rickettsial infections of Ctenocephalides felis, the predominant fleas species obtained from opossums (Didelphis virginiana) and domestic cats (Felis catus), collected from case exposure sites and other areas in Orange County. In addition, we assessed the prevalence of IgG antibodies against spotted fever group (SFGR) and typhus group (TGR) rickettsiae in opossum sera. Of the 597 flea specimens collected from opossums and cats, 37.2% tested positive for Rickettsia. PCR and sequencing of rickettsial genes obtained from C. felis flea DNA preparations revealed the presence of R. typhi (1.3%), R. felis (28.0%) and R. felis-like organisms (7.5%). Sera from opossums contained TGR-specific (40.84%), but not SFGR-specific antibodies. The detection of R. felis and R. typhi in the C. felis fleas in Orange County highlights the potential risk for human infection with either of these pathogens, and underscores the need for further investigations incorporating specimens from humans, animal hosts, and invertebrate vectors in endemic areas. Such studies will be essential for establishing a link in the ongoing flea-borne rickettsioses outbreaks. PMID:27537367

  8. Retracing the evolutionary path that led to flea-borne transmission of Yersinia pestis.

    PubMed

    Sun, Yi-Cheng; Jarrett, Clayton O; Bosio, Christopher F; Hinnebusch, B Joseph

    2014-05-14

    Yersinia pestis is an arthropod-borne bacterial pathogen that evolved recently from Yersinia pseudotuberculosis, an enteric pathogen transmitted via the fecal-oral route. This radical ecological transition can be attributed to a few discrete genetic changes from a still-extant recent ancestor, thus providing a tractable case study in pathogen evolution and emergence. Here, we determined the genetic and mechanistic basis of the evolutionary adaptation of Y. pestis to flea-borne transmission. Remarkably, only four minor changes in the bacterial progenitor, representing one gene gain and three gene losses, enabled transmission by flea vectors. All three loss-of-function mutations enhanced cyclic-di-GMP-mediated bacterial biofilm formation in the flea foregut, which greatly increased transmissibility. Our results suggest a step-wise evolutionary model in which Y. pestis emerged as a flea-borne clone, with each genetic change incrementally reinforcing the transmission cycle. The model conforms well to the ecological theory of adaptive radiation. PMID:24832452

  9. Ecological Opportunity, Evolution, and the Emergence of Flea-Borne Plague.

    PubMed

    Hinnebusch, B Joseph; Chouikha, Iman; Sun, Yi-Cheng

    2016-07-01

    The plague bacillus Yersinia pestis is unique among the pathogenic Enterobacteriaceae in utilizing an arthropod-borne transmission route. Transmission by fleabite is a recent evolutionary adaptation that followed the divergence of Y. pestis from the closely related food- and waterborne enteric pathogen Yersinia pseudotuberculosis A combination of population genetics, comparative genomics, and investigations of Yersinia-flea interactions have disclosed the important steps in the evolution and emergence of Y. pestis as a flea-borne pathogen. Only a few genetic changes, representing both gene gain by lateral transfer and gene loss by loss-of-function mutation (pseudogenization), were fundamental to this process. The emergence of Y. pestis fits evolutionary theories that emphasize ecological opportunity in adaptive diversification and rapid emergence of new species. PMID:27160296

  10. Molecular detection of Rickettsia felis and Candidatus Rickettsia Asemboensis in Fleas from Human Habitats, Asembo, Kenya

    PubMed Central

    Jiang, Ju; Maina, Alice N.; Knobel, Darryn L.; Cleaveland, Sarah; Laudisoit, Anne; Wamburu, Kabura; Ogola, Eric; Parola, Philippe; Breiman, Robert F.; Njenga, M. Kariuki

    2013-01-01

    Abstract The flea-borne rickettsioses murine typhus (Rickettsia typhi) and flea-borne spotted fever (FBSF) (Rickettsia felis) are febrile diseases distributed among humans worldwide. Murine typhus has been known to be endemic to Kenya since the 1950s, but FBSF was only recently documented in northeastern (2010) and western (2012) Kenya. To characterize the potential exposure of humans in Kenya to flea-borne rickettsioses, a total of 330 fleas (134 pools) including 5 species (Xenopsylla cheopis, Ctenocephalides felis, Ctenocephalides canis, Pulex irritans, and Echidnophaga gallinacea) were collected from domestic and peridomestic animals and from human dwellings within Asembo, western Kenya. DNA was extracted from the 134 pooled flea samples and 89 (66.4%) pools tested positively for rickettsial DNA by 2 genus-specific quantitative real-time PCR (qPCR) assays based upon the citrate synthase (gltA) and 17-kD antigen genes and the Rfelis qPCR assay. Sequences from the 17-kD antigen gene, the outer membrane protein (omp)B, and 2 R. felis plasmid genes (pRF and pRFd) of 12 selected rickettsia-positive samples revealed a unique Rickettsia sp. (n=11) and R. felis (n=1). Depiction of the new rickettsia by multilocus sequence typing (MLST) targeting the 16S rRNA (rrs), 17-kD antigen gene, gltA, ompA, ompB, and surface cell antigen 4 (sca4), shows that it is most closely related to R. felis but genetically dissimilar enough to be considered a separate species provisionally named Candidatus Rickettsia asemboensis. Subsequently, 81 of the 134 (60.4%) flea pools tested positively for Candidatus Rickettsia asemboensis by a newly developed agent-specific qPCR assay, Rasemb. R. felis was identified in 9 of the 134 (6.7%) flea pools, and R. typhi the causative agent of murine typhus was not detected in any of 78 rickettsia-positive pools assessed using a species-specific qPCR assay, Rtyph. Two pools were found to contain both R. felis and Candidatus Rickettsia asemboensis DNA and 1

  11. Genomic diversification in strains of Rickettsia felis Isolated from different arthropods.

    PubMed

    Gillespie, Joseph J; Driscoll, Timothy P; Verhoeve, Victoria I; Utsuki, Tadanobu; Husseneder, Claudia; Chouljenko, Vladimir N; Azad, Abdu F; Macaluso, Kevin R

    2015-01-01

    Rickettsia felis (Alphaproteobacteria: Rickettsiales) is the causative agent of an emerging flea-borne rickettsiosis with worldwide occurrence. Originally described from the cat flea, Ctenocephalides felis, recent reports have identified R. felis from other flea species, as well as other insects and ticks. This diverse host range for R. felis may indicate an underlying genetic variability associated with host-specific strains. Accordingly, to determine a potential genetic basis for host specialization, we sequenced the genome of R. felis str. LSU-Lb, which is an obligate mutualist of the parthenogenic booklouse Liposcelis bostrychophila (Insecta: Psocoptera). We also sequenced the genome of R. felis str. LSU, the second genome sequence for cat flea-associated strains (cf. R. felis str. URRWXCal2), which are presumably facultative parasites of fleas. Phylogenomics analysis revealed R. felis str. LSU-Lb diverged from the flea-associated strains. Unexpectedly, R. felis str. LSU was found to be divergent from R. felis str. URRWXCal2, despite sharing similar hosts. Although all three R. felis genomes contain the pRF plasmid, R. felis str. LSU-Lb carries an additional unique plasmid, pLbaR (plasmid of L. bostrychophila associated Rickettsia), nearly half of which encodes a unique 23-gene integrative conjugative element. Remarkably, pLbaR also encodes a repeats-in-toxin-like type I secretion system and associated toxin, heretofore unknown from other Rickettsiales genomes, which likely originated from lateral gene transfer with another obligate intracellular parasite of arthropods, Cardinium (Bacteroidetes). Collectively, our study reveals unexpected genomic diversity across three R. felis strains and identifies several diversifying factors that differentiate facultative parasites of fleas from obligate mutualists of booklice. PMID:25477419

  12. Genomic Diversification in Strains of Rickettsia felis Isolated from Different Arthropods

    PubMed Central

    Gillespie, Joseph J.; Driscoll, Timothy P.; Verhoeve, Victoria I.; Utsuki, Tadanobu; Husseneder, Claudia; Chouljenko, Vladimir N.; Azad, Abdu F.; Macaluso, Kevin R.

    2015-01-01

    Rickettsia felis (Alphaproteobacteria: Rickettsiales) is the causative agent of an emerging flea-borne rickettsiosis with worldwide occurrence. Originally described from the cat flea, Ctenocephalides felis, recent reports have identified R. felis from other flea species, as well as other insects and ticks. This diverse host range for R. felis may indicate an underlying genetic variability associated with host-specific strains. Accordingly, to determine a potential genetic basis for host specialization, we sequenced the genome of R. felis str. LSU-Lb, which is an obligate mutualist of the parthenogenic booklouse Liposcelis bostrychophila (Insecta: Psocoptera). We also sequenced the genome of R. felis str. LSU, the second genome sequence for cat flea-associated strains (cf. R. felis str. URRWXCal2), which are presumably facultative parasites of fleas. Phylogenomics analysis revealed R. felis str. LSU-Lb diverged from the flea-associated strains. Unexpectedly, R. felis str. LSU was found to be divergent from R. felis str. URRWXCal2, despite sharing similar hosts. Although all three R. felis genomes contain the pRF plasmid, R. felis str. LSU-Lb carries an additional unique plasmid, pLbaR (plasmid of L. bostrychophila associated Rickettsia), nearly half of which encodes a unique 23-gene integrative conjugative element. Remarkably, pLbaR also encodes a repeats-in-toxin-like type I secretion system and associated toxin, heretofore unknown from other Rickettsiales genomes, which likely originated from lateral gene transfer with another obligate intracellular parasite of arthropods, Cardinium (Bacteroidetes). Collectively, our study reveals unexpected genomic diversity across three R. felis strains and identifies several diversifying factors that differentiate facultative parasites of fleas from obligate mutualists of booklice. PMID:25477419

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

    PubMed

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

    2015-09-01

    Ticks are second to mosquitoes as the most important disease vectors, and recent decades have witnessed the emergence of many novel tick-borne rickettsial diseases, but systematic surveys of ticks and tick-borne rickettsioses are generally lacking in Asia. We collected and identified ticks from small mammal hosts between 2006 and 2010 in different parts of Taiwan. Rickettsia spp. infections in ticks were identified by targeting ompB and gltA genes with nested polymerase chain reaction. In total, 2,732 ticks were collected from 1,356 small mammals. Rhipicephalus haemaphysaloides Supino (51.8% of total ticks), Haemaphysalis bandicota Hoogstraal & Kohls (28.0%), and Ixodes granulatus Supino (20.0%) were the most common tick species, and Rattus losea Swinhoe (44.7% of total ticks) and Bandicota indica Bechstein (39.9%) were the primary hosts. The average Rickettsia infective rate in 329 assayed ticks was 31.9% and eight Rickettsia spp. or closely related species were identified. This study shows that rickettsiae-infected ticks are widespread in Taiwan, with a high diversity of Rickettsia spp. circulating in the ticks. Because notifiable rickettsial diseases in Taiwan only include mite-borne scrub typhus and flea-borne murine typhus, more studies are warranted for a better understanding of the real extent of human risks to rickettsioses in Taiwan. PMID:26336223

  14. Detection of Rickettsia felis, Rickettsia typhi, Bartonella Species and Yersinia pestis in Fleas (Siphonaptera) from Africa

    PubMed Central

    Leulmi, Hamza; Socolovschi, Cristina; Laudisoit, Anne; Houemenou, Gualbert; Davoust, Bernard; Bitam, Idir; Raoult, Didier; Parola, Philippe

    2014-01-01

    Little is known about the presence/absence and prevalence of Rickettsia spp, Bartonella spp. and Yersinia pestis in domestic and urban flea populations in tropical and subtropical African countries. Methodology/Principal findings Fleas collected in Benin, the United Republic of Tanzania and the Democratic Republic of the Congo were investigated for the presence and identity of Rickettsia spp., Bartonella spp. and Yersinia pestis using two qPCR systems or qPCR and standard PCR. In Xenopsylla cheopis fleas collected from Cotonou (Benin), Rickettsia typhi was detected in 1% (2/199), and an uncultured Bartonella sp. was detected in 34.7% (69/199). In the Lushoto district (United Republic of Tanzania), R. typhi DNA was detected in 10% (2/20) of Xenopsylla brasiliensis, and Rickettsia felis was detected in 65% (13/20) of Ctenocephalides felis strongylus, 71.4% (5/7) of Ctenocephalides canis and 25% (5/20) of Ctenophthalmus calceatus calceatus. In the Democratic Republic of the Congo, R. felis was detected in 56.5% (13/23) of Ct. f. felis from Kinshasa, in 26.3% (10/38) of Ct. f. felis and 9% (1/11) of Leptopsylla aethiopica aethiopica from Ituri district and in 19.2% (5/26) of Ct. f. strongylus and 4.7% (1/21) of Echidnophaga gallinacea. Bartonella sp. was also detected in 36.3% (4/11) of L. a. aethiopica. Finally, in Ituri, Y. pestis DNA was detected in 3.8% (1/26) of Ct. f. strongylus and 10% (3/30) of Pulex irritans from the villages of Wanyale and Zaa. Conclusion Most flea-borne infections are neglected diseases which should be monitored systematically in domestic rural and urban human populations to assess their epidemiological and clinical relevance. Finally, the presence of Y. pestis DNA in fleas captured in households was unexpected and raises a series of questions regarding the role of free fleas in the transmission of plague in rural Africa, especially in remote areas where the flea density in houses is high. PMID:25299702

  15. Rickettsia africae and Candidatus Rickettsia barbariae in Ticks in Israel

    PubMed Central

    Waner, Trevor; Keysary, Avi; Eremeeva, Marina E.; Din, Adi Beth; Mumcuoglu, Kosta Y.; King, Roni; Atiya-Nasagi, Yafit

    2014-01-01

    DNA of several spotted fever group rickettsiae was found in ticks in Israel. The findings include evidence for the existence of Rickettsia africae and Candidatus Rickettsia barbariae in ticks in Israel. The DNA of R. africae was detected in a Hyalomma detritum tick from a wild boar and DNA of C. Rickettsia barbariae was detected in Rhipicephalus turanicus and Rhipicephalus sanguineus collected from vegetation. The DNA of Rickettsia massiliae was found in Rh. sanguineus and Haemaphysalis erinacei, whereas DNA of Rickettsia sibirica mongolitimonae was detected in a Rhipicephalus (Boophilus) annulatus. Clinicians should be aware that diseases caused by a variety of rickettsiae previously thought to be present only in other countries outside of the Middle East may infect residents of Israel who have not necessarily traveled overseas. Furthermore, this study reveals again that the epidemiology of the spotted fever group rickettsiae may not only involve Rickettsia conorii but may include other rickettsiae. PMID:24615133

  16. Rickettsia and Bartonella Species in Fleas from Reunion Island

    PubMed Central

    Dieme, Constentin; Parola, Philippe; Guernier, Vanina; Lagadec, Erwan; Le Minter, Gildas; Balleydier, Elsa; Pagès, Frederic; Dellagi, Koussay; Tortosa, Pablo; Raoult, Didier; Socolovschi, Cristina

    2015-01-01

    Rickettsia felis, Rickettsia typhi, and Bartonella DNA was detected by molecular tools in 12% of Rattus rattus fleas (Xenopsylla species) collected from Reunion Island. One-third of the infested commensal rodents captured during 1 year carried at least one infected flea. As clinical signs of these zoonoses are non-specific, they are often misdiagnosed. PMID:25646263

  17. Rickettsia felis in cat fleas, Ctenocephalides felis parasitizing opossums, San Bernardino County, California.

    PubMed

    Abramowicz, K F; Wekesa, J W; Nwadike, C N; Zambrano, M L; Karpathy, S E; Cecil, D; Burns, J; Hu, R; Eremeeva, M E

    2012-12-01

    Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouché, 1835). The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine typhus in this area, no evidence for circulation of R. typhi in fleas was found during the present study. Factors contributing to the absence of R. typhi in these cat fleas in contrast to its presence in cat fleas from Orange and Los Angeles Counties are unknown and need to be investigated further in San Bernardino County. PMID:22712460

  18. A Molecular Survey of Rickettsia felis in Fleas from Cats and Dogs in Sicily (Southern Italy)

    PubMed Central

    Giudice, Elisabetta; Di Pietro, Simona; Alaimo, Antonio; Blanda, Valeria; Lelli, Rossella; Francaviglia, Francesco; Caracappa, Santo; Torina, Alessandra

    2014-01-01

    Rickettsia felis, the agent of flea-borne spotted fever, has a cosmopolitan distribution. Its pathogenic role in humans has been demonstrated through molecular and serologic tests in several cases. The cat flea (Ctenocephalides felis) is considered the main reservoir and the biological vector. The aim of this study was to assess the presence and occurrence of R. felis in fleas collected from dogs and cats in various sites of Palermo (Sicily). Between August and October 2012, 134 fleas were collected from 42 animals: 37 fleas from 13 dogs and 97 fleas from 29 cats. Two species of fleas were identified: 132 Ctenocephalides felis (98.51%) collected on all animals and only two C. canis (1.49%) on one dog. Out of 132 C. felis, 34 (25.76%), 12 from dogs (32.43%) and 22 (22.68%) from cats, were positive for R. felis DNA by a polymerase chain reaction (PCR), confirmed by sequencing. The only two C. canis fleas were negative. About half of examined animals (47.62%, 20/42) were infested with at least one infected flea; in particular 46.15% of dogs (6/13) and 48.28% of cats (14/29). It seems that in the Palermo district there is a peri-domestic cycle, with a relatively high prevalence of R. felis infection in the cat flea, an insect widely diffused in home environments and which can frequently bite humans. The results also suggest that R. felis should be considered in the human differential diagnosis of any spotted-like fever or febrile illness without a clear source of infection in Sicily, especially if the patient is known to have been exposed to flea bites. PMID:25203839

  19. Immunoproteomic profiling of Rickettsia parkeri and Rickettsia amblyommii.

    PubMed

    Pornwiroon, Walairat; Bourchookarn, Apichai; Paddock, Christopher D; Macaluso, Kevin R

    2015-09-01

    Rickettsia parkeri is an Amblyomma-associated, spotted fever group Rickettsia species that causes an eschar-associated, febrile illness in multiple countries throughout the Western Hemisphere. Many other rickettsial species of known or uncertain pathogenicity have been detected in Amblyomma spp. ticks in the Americas, including Rickettsia amblyommii, "Candidatus Rickettsia andeanae" and Rickettsia rickettsii. In this study, we utilized an immunoproteomic approach to compare antigenic profiles of low-passage isolates of R. parkeri and R. amblyommii with serum specimens from patients with PCR- and culture-confirmed infections with R. parkeri. Five immunoreactive proteins of R. amblyommii and nine immunoreactive proteins of R. parkeri were identified by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry. Four of these, including the outer membrane protein (Omp) A, OmpB, translation initiation factor IF-2, and cell division protein FtsZ, were antigens common to both rickettsiae. Serum specimens from patients with R. parkeri rickettsiosis reacted specifically with cysteinyl-tRNA synthetase, DNA-directed RNA polymerase subunit alpha, putative sigma (54) modulation protein, chaperonin GroEL, and elongation factor Tu of R. parkeri which have been reported as virulence factors in other bacterial species. Unique antigens identified in this study may be useful for further development of the better serological assays for diagnosing infection caused by R. parkeri. PMID:26234571

  20. Analysis of Rickettsia typhi-infected and uninfected cat flea (Ctenocephalides felis) midgut cDNA libraries: deciphering molecular pathways involved in host response to R. typhi infection

    PubMed Central

    Dreher-Lesnick, S. M.; Ceraul, S. M.; Lesnick, S. C.; Gillespie, J. J.; Anderson, J. M.; Jochim, R. C.; Valenzuela, J. G.; Azad, A. F.

    2011-01-01

    Murine typhus is a flea-borne febrile illness that is caused by the obligate intracellular bacterium, Rickettsia typhi. The cat flea, Ctenocephalides felis, acquires R. typhi by imbibing a bloodmeal from a rickettsemic vertebrate host. To explore which transcripts are expressed in the midgut in response to challenge with R. typhi, cDNA libraries of R. typhi-infected and uninfected midguts of C. felis were constructed. In this study, we examined midgut transcript levels for select C. felis serine proteases, GTPases and defence response genes, all thought to be involved in the fleas response to feeding or infection. An increase in gene expression was observed for the serine protease inhibitors and vesicular trafficking proteins in response to feeding. In addition, R. typhi infection resulted in an increase in gene expression for the chymotrypsin and rab5 that we studied. Interestingly, R. typhi infection had little effect on expression of any of the defence response genes that we studied. We are unsure as to the physiological significance of these gene expression profiles and are currently investigating their potential roles as it pertains to R. typhi infection. To our knowledge, this is the first report of differential expression of flea transcripts in response to infection with R. typhi. PMID:20017753

  1. Rickettsiae and rickettsial diseases

    PubMed Central

    Brezina, R.; Murray, E. S.; Tarizzo, M. L.; Bögel, K.

    1973-01-01

    This paper summarizes present knowledge on rickettsiae and rickettsial diseases, and on their epidemiological characteristics, control, and public health significance. There are many natural foci of rickettsial diseases, from where the disease may spread to other areas in the world under changing socioeconomic conditions. Because of rapid long-distance travel, sporadic cases of serious rickettsial diseases may today appear far from endemic areas where the infection occurred. Even in endemic areas the disease may be misdiagnosed and deaths may occur as a result of inadequate treatment. Rapid treatment of rickettsial infections (preferably with tetracyclines) is therefore most important. Epidemic louse-borne typhus, though no longer subject to the International Health Regulations, remains one of the diseases in the WHO epidemiological surveillance programme. This disease continues to be a major cause of morbidity and mortality in some parts of Africa and it is present also in parts of the Americas and of Asia. Scrub typhus remains a continuing and serious public health problem in areas of South-East Asia and in the Western Pacific. The annual number of reported cases of Rocky Mountain spotted fever in the USA showed an increase during the last two decades, which may be due to improved recognition as well as to increased outdoor activities and migration of people from the city centres to the suburbs. Related forms of tick-borne typhus occur in South America, the Mediterranean region, Africa, South-East Asia, the Far East, and the Western Pacific. Increasing in number, though still sporadic, are reports of serious illness from chronic Q fever infection in many parts of the world. PMID:4547297

  2. Laboratory Maintenance of Rickettsia rickettsii

    PubMed Central

    Beier-Sexton, Magda; Azad, Abdu F.

    2009-01-01

    This unit includes protocols for the laboratory maintenance of the obligate intracellular bacterium Rickettsia rickettsii, including propagation in mammalian cell cultures, as well as isolation, counting, and storage procedures. Regulations for working with R. rickettsii in biosafety level 3 containment are also discussed. PMID:19016440

  3. Candidatus Rickettsia hoogstraalii in Ethiopian Argas persicus ticks.

    PubMed

    Pader, Vera; Nikitorowicz Buniak, Joanna; Abdissa, Alemseged; Adamu, Haileeysus; Tolosa, Tadele; Gashaw, Abebaw; Cutler, Ronald R; Cutler, Sally J

    2012-12-01

    Ethiopian soft ticks Argas persicus, hard ticks including both Amblyomma variegatum and Rhipicephalus (Boophilus) spp., and fleas were collected from livestock, traditional human dwellings, and cracks and crevices of trees. They were assessed in pools for the presence of Rickettsia using PCR-based methods. The extracted tick DNA was subjected to molecular screening for Rickettsia, which revealed 50.5% of the pooled samples to be positive for Rickettsia spp. These were then subjected to multi-gene analysis using both outer surface proteins and housekeeping genes with proven discriminatory potential. Sequencing of the citrate synthase and outer membrane genes clearly led to the identification of three distinct rickettsial species, Candidatus Rickettsia hoogstraalii in Argas persicus ticks; R. africae in hard tick pools, and R. felis in fleas. Furthermore, we demonstrated the presence of the plasmid-borne small heat-shock protein gene hsp2 in DNA from A. persicus ticks suggesting that Candidatus R. hoogstraalii carried by these ticks possess a plasmid. Unlike chromosomal gene sequences, the hsp2 gene failed to cluster with Candidatus R. hoogstraalii, instead falling into an isolated separate clade, suggesting a different origin for the plasmid. PMID:23140898

  4. Secretome of obligate intracellular Rickettsia

    PubMed Central

    Gillespie, Joseph J.; Kaur, Simran J.; Rahman, M. Sayeedur; Rennoll-Bankert, Kristen; Sears, Khandra T.; Beier-Sexton, Magda; Azad, Abdu F.

    2014-01-01

    The genus Rickettsia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) is comprised of obligate intracellular parasites, with virulent species of interest both as causes of emerging infectious diseases and for their potential deployment as bioterrorism agents. Currently, there are no effective commercially available vaccines, with treatment limited primarily to tetracycline antibiotics, although others (e.g. josamycin, ciprofloxacin, chloramphenicol, and azithromycin) are also effective. Much of the recent research geared toward understanding mechanisms underlying rickettsial pathogenicity has centered on characterization of secreted proteins that directly engage eukaryotic cells. Herein, we review all aspects of the Rickettsia secretome, including six secretion systems, 19 characterized secretory proteins, and potential moonlighting proteins identified on surfaces of multiple Rickettsia species. Employing bioinformatics and phylogenomics, we present novel structural and functional insight on each secretion system. Unexpectedly, our investigation revealed that the majority of characterized secretory proteins have not been assigned to their cognate secretion pathways. Furthermore, for most secretion pathways, the requisite signal sequences mediating translocation are poorly understood. As a blueprint for all known routes of protein translocation into host cells, this resource will assist research aimed at uniting characterized secreted proteins with their apposite secretion pathways. Furthermore, our work will help in the identification of novel secreted proteins involved in rickettsial ‘life on the inside’. PMID:25168200

  5. Evolution and diversity of Rickettsia bacteria

    PubMed Central

    Weinert, Lucy A; Werren, John H; Aebi, Alexandre; Stone, Graham N; Jiggins, Francis M

    2009-01-01

    Background Rickettsia are intracellular symbionts of eukaryotes that are best known for infecting and causing serious diseases in humans and other mammals. All known vertebrate-associated Rickettsia are vectored by arthropods as part of their life-cycle, and many other Rickettsia are found exclusively in arthropods with no known secondary host. However, little is known about the biology of these latter strains. Here, we have identified 20 new strains of Rickettsia from arthropods, and constructed a multi-gene phylogeny of the entire genus which includes these new strains. Results We show that Rickettsia are primarily arthropod-associated bacteria, and identify several novel groups within the genus. Rickettsia do not co-speciate with their hosts but host shifts most often occur between related arthropods. Rickettsia have evolved adaptations including transmission through vertebrates and killing males in some arthropod hosts. We uncovered one case of horizontal gene transfer among Rickettsia, where a strain is a chimera from two distantly related groups, but multi-gene analysis indicates that different parts of the genome tend to share the same phylogeny. Conclusion Approximately 150 million years ago, Rickettsia split into two main clades, one of which primarily infects arthropods, and the other infects a diverse range of protists, other eukaryotes and arthropods. There was then a rapid radiation about 50 million years ago, which coincided with the evolution of life history adaptations in a few branches of the phylogeny. Even though Rickettsia are thought to be primarily transmitted vertically, host associations are short lived with frequent switching to new host lineages. Recombination throughout the genus is generally uncommon, although there is evidence of horizontal gene transfer. A better understanding of the evolution of Rickettsia will help in the future to elucidate the mechanisms of pathogenicity, transmission and virulence. PMID:19187530

  6. Genome Sequence of Rickettsia bellii Illuminates the Role of Amoebae in Gene Exchanges between Intracellular Pathogens

    PubMed Central

    Ogata, Hiroyuki; La Scola, Bernard; Audic, Stéphane; Renesto, Patricia; Blanc, Guillaume; Robert, Catherine; Fournier, Pierre-Edouard; Claverie, Jean-Michel; Raoult, Didier

    2006-01-01

    The recently sequenced Rickettsia felis genome revealed an unexpected plasmid carrying several genes usually associated with DNA transfer, suggesting that ancestral rickettsiae might have been endowed with a conjugation apparatus. Here we present the genome sequence of Rickettsia bellii, the earliest diverging species of known rickettsiae. The 1,552,076 base pair–long chromosome does not exhibit the colinearity observed between other rickettsia genomes, and encodes a complete set of putative conjugal DNA transfer genes most similar to homologues found in Protochlamydia amoebophila UWE25, an obligate symbiont of amoebae. The genome exhibits many other genes highly similar to homologues in intracellular bacteria of amoebae. We sought and observed sex pili-like cell surface appendages for R. bellii. We also found that R. bellii very efficiently multiplies in the nucleus of eukaryotic cells and survives in the phagocytic amoeba, Acanthamoeba polyphaga. These results suggest that amoeba-like ancestral protozoa could have served as a genetic “melting pot” where the ancestors of rickettsiae and other bacteria promiscuously exchanged genes, eventually leading to their adaptation to the intracellular lifestyle within eukaryotic cells. PMID:16703114

  7. Rickettsia parkeri in Amblyomma triste from Uruguay

    PubMed Central

    Portillo, Aránzazu; Estrada-Peña, Agustín; Castro, Oscar; Cabrera, Perla A.; Oteo, José A.

    2004-01-01

    Our goal was to detect whether spotted fever group Rickettsia are found in the suspected vector of rickettsioses, Amblyomma triste, in Uruguay. Rickettsia parkeri was detected in A. triste, which suggests that this species could be considered a pathogenic agent responsible for human rickettsioses in Uruguay. PMID:15496258

  8. Loop-Mediated Isothermal Amplification for Rickettsia typhi (the Causal Agent of Murine Typhus): Problems with Diagnosis at the Limit of Detection

    PubMed Central

    Dittrich, Sabine; Castonguay-Vanier, Josée; Moore, Catrin E.; Thongyoo, Narongchai; Newton, Paul N.

    2014-01-01

    Murine typhus is a flea-borne disease of worldwide distribution caused by Rickettsia typhi. Although treatment with tetracycline antibiotics is effective, treatment is often misguided or delayed due to diagnostic difficulties. As the gold standard immunofluorescence assay is imperfect, we aimed to develop and evaluate a loop-mediated isothermal amplification (LAMP) assay. LAMP assays have the potential to fulfill the WHO ASSURED criteria (affordable, sensitive, specific, user friendly, robust and rapid, equipment free, deliverable to those who need them) for diagnostic methodologies, as they can detect pathogen-derived nucleic acid with low technical expenditure. The LAMP assay was developed using samples of bacterial isolates (n = 41), buffy coat specimens from R. typhi PCR-positive Lao patients (n = 42), and diverse negative controls (n = 47). The method was then evaluated prospectively using consecutive patients with suspected scrub typhus or murine typhus (n = 266). The limit of detection was ∼40 DNA copies/LAMP reaction, with an analytical sensitivity of <10 DNA copies/reaction based on isolate dilutions. Despite these low cutoffs, the clinical sensitivity was disappointing, with 48% (95% confidence interval [95% CI], 32.5 to 62.7%) (specificity, 100% [95% CI, 100 to 100%]) in the developmental phase and 33% (95% CI, 9.2 to 56.8%) (specificity, 98.5% [95% CI, 97.0% to 100%]) in the prospective study. This low diagnostic accuracy was attributed to low patient R. typhi bacterial loads (median, 210 DNA copies/ml blood; interquartile range, 130 to 500). PCR-positive but LAMP-negative samples demonstrated significantly lower bacterial loads than LAMP-positive samples. Our findings highlight the diagnostic challenges for diseases with low pathogen burdens and emphasize the need to integrate pathogen biology with improved template production for assay development strategies. PMID:24371248

  9. Integrated morphological and molecular identification of cat fleas (Ctenocephalides felis) and dog fleas (Ctenocephalides canis) vectoring Rickettsia felis in central Europe.

    PubMed

    Lawrence, Andrea L; Hii, Sze-Fui; Jirsová, Dagmar; Panáková, Lucia; Ionică, Angela M; Gilchrist, Katrina; Modrý, David; Mihalca, Andrei D; Webb, Cameron E; Traub, Rebecca J; Šlapeta, Jan

    2015-06-15

    Fleas of the genus Ctenocephalides are the most common ectoparasites infesting dogs and cats world-wide. The species Ctenocephalides felis and Ctenocephalides canis are competent vectors for zoonotic pathogens such as Rickettsia felis and Bartonella spp. Improved knowledge on the diversity and phylogenetics of fleas is important for understanding flea-borne pathogen transmission cycles. Fleas infesting privately owned dogs and cats from the Czech Republic (n=97) and Romania (n=66) were subjected to morphological and molecular identification and phylogenetic analysis. There were a total of 59 (60.82%) cat fleas (Ctenocephalides felis felis), 30 (30.93%) dog fleas (Ctenocephalides canis), 7 (7.22%) European chicken fleas (Ceratophyllus gallinae) and 1 (1.03%) northern rat flea (Nosopsyllus fasciatus) collected in the Czech Republic. Both C. canis and C. felis felis were identified in Romania. Mitochondrial DNA sequencing at the cox1 gene on a cohort of 40 fleas revealed the cosmopolitan C. felis felis clade represented by cox1 haplotype 1 is present in the Czech Republic. A new C. felis felis clade from both the Czech Republic and Romania is also reported. A high proportion of C. canis was observed from dogs and cats in the current study and phylogeny revealed that C. canis forms a sister clade to the oriental cat flea Ctenocephalides orientis (syn. C. felis orientis). Out of 33 fleas tested, representing C. felis felis, C. canis and Ce. gallinae, 7 (21.2%) were positive for R. felis using diagnostic real-time PCR targeting the gltA gene and a conventional PCR targeting the ompB gene. No samples tested positive for Bartonella spp. using a diagnostic real-time PCR assay targeting ssrA gene. This study confirms high genetic diversity of C. felis felis globally and serves as a foundation to understand the implication for zoonotic disease carriage and transmission by the flea genus Ctenocephalides. PMID:25899079

  10. Spotted fever Rickettsia species in Hyalomma and Ixodes ticks infesting migratory birds in the European Mediterranean area

    PubMed Central

    2014-01-01

    Background A few billion birds migrate annually between their breeding grounds in Europe and their wintering grounds in Africa. Many bird species are tick-infested, and as a result of their innate migratory behavior, they contribute significantly to the geographic distribution of pathogens, including spotted fever rickettsiae. The aim of the present study was to characterize, in samples from two consecutive years, the potential role of migrant birds captured in Europe as disseminators of Rickettsia-infected ticks. Methods Ticks were collected from a total of 14,789 birds during their seasonal migration northwards in spring 2009 and 2010 at bird observatories on two Mediterranean islands: Capri and Antikythira. All ticks were subjected to RNA extraction followed by cDNA synthesis and individually assayed with a real-time PCR targeting the citrate synthase (gltA) gene. For species identification of Rickettsia, multiple genes were sequenced. Results Three hundred and ninety-eight (2.7%) of all captured birds were tick-infested; some birds carried more than one tick. A total number of 734 ticks were analysed of which 353 ± 1 (48%) were Rickettsia-positive; 96% were infected with Rickettsia aeschlimannii and 4% with Rickettsia africae or unidentified Rickettsia species. The predominant tick taxon, Hyalomma marginatum sensu lato constituted 90% (n = 658) of the ticks collected. The remaining ticks were Ixodes frontalis, Amblyomma sp., Haemaphysalis sp., Rhipicephalus sp. and unidentified ixodids. Most ticks were nymphs (66%) followed by larvae (27%) and adult female ticks (0.5%). The majority (65%) of ticks was engorged and nearly all ticks contained visible blood. Conclusions Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations. The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination. PMID:25011617

  11. Rickettsia parkeri Rickettsiosis, Arizona, USA.

    PubMed

    Herrick, Kristen L; Pena, Sandra A; Yaglom, Hayley D; Layton, Brent J; Moors, Amanda; Loftis, Amanda D; Condit, Marah E; Singleton, Joseph; Kato, Cecilia Y; Denison, Amy M; Ng, Dianna; Mertins, James W; Paddock, Christopher D

    2016-05-01

    In the United States, all previously reported cases of Rickettsia parkeri rickettsiosis have been linked to transmission by the Gulf Coast tick (Amblyomma maculatum). Here we describe 1 confirmed and 1 probable case of R. parkeri rickettsiosis acquired in a mountainous region of southern Arizona, well beyond the recognized geographic range of A. maculatum ticks. The likely vector for these 2 infections was identified as the Amblyomma triste tick, a Neotropical species only recently recognized in the United States. Identification of R. parkeri rickettsiosis in southern Arizona demonstrates a need for local ecologic and epidemiologic assessments to better understand geographic distribution and define public health risk. Education and outreach aimed at persons recreating or working in this region of southern Arizona would improve awareness and promote prevention of tickborne rickettsioses. PMID:27089251

  12. Rickettsia parkeri Rickettsiosis, Arizona, USA

    PubMed Central

    Herrick, Kristen L.; Pena, Sandra A.; Yaglom, Hayley D.; Layton, Brent J.; Moors, Amanda; Loftis, Amanda D.; Condit, Marah E.; Singleton, Joseph; Kato, Cecilia Y.; Denison, Amy M.; Ng, Dianna; Mertins, James W.

    2016-01-01

    In the United States, all previously reported cases of Rickettsia parkeri rickettsiosis have been linked to transmission by the Gulf Coast tick (Amblyomma maculatum). Here we describe 1 confirmed and 1 probable case of R. parkeri rickettsiosis acquired in a mountainous region of southern Arizona, well beyond the recognized geographic range of A. maculatum ticks. The likely vector for these 2 infections was identified as the Amblyomma triste tick, a Neotropical species only recently recognized in the United States. Identification of R. parkeri rickettsiosis in southern Arizona demonstrates a need for local ecologic and epidemiologic assessments to better understand geographic distribution and define public health risk. Education and outreach aimed at persons recreating or working in this region of southern Arizona would improve awareness and promote prevention of tickborne rickettsioses. PMID:27089251

  13. Absence of Rickettsia rickettsii and Occurrence of Other Spotted Fever Group Rickettsiae in Ticks from Tennessee

    PubMed Central

    Moncayo, Abelardo C.; Cohen, Sara B.; Fritzen, Charissa M.; Huang, Eileen; Yabsley, Michael J.; Freye, James D.; Dunlap, Brett G.; Huang, Junjun; Mead, Daniel G.; Jones, Timothy F.; Dunn, John R.

    2010-01-01

    Rocky Mountain spotted fever (RMSF) is the most common tick-borne illness in Tennessee. Little is known about the occurrence of R. rickettsii, the causative agent, in ticks in Tennessee. To better understand the prevalence and distribution of rickettsial agents in ticks, we tested 1,265 Amblyomma, Dermacentor, and Ixodes adult and nymphal ticks. Additionally, we tested 231 Amblyomma americanum larvae. Ticks were collected from 49 counties from humans, wild animals, domestic canines, and flannel drags. Spotted fever group rickettsiae (SFGR) DNA was detected by polymerase chain reaction (PCR) in 32% of adult and nymphal ticks. A total minimum infection rate of 85.63 was found in larval pools tested. Three rickettsial species, Rickettsia montana, Rickettsia amblyommii, and Rickettsia cooleyi were identified by molecular analysis. Rickettsia rickettsii was not detected. This study suggests that some RMSF cases reported in Tennessee may be caused by cross-reactivity with other SFGR antigenically related to R. rickettsii. PMID:20810834

  14. Molecular detection of Rickettsia conorii and other zoonotic spotted fever group rickettsiae in ticks, Romania.

    PubMed

    Ionita, Mariana; Silaghi, Cornelia; Mitrea, Ioan Liviu; Edouard, Sophie; Parola, Philippe; Pfister, Kurt

    2016-02-01

    The diverse tick fauna as well as the abundance of tick populations in Romania represent potential risks for both human and animal health. Spotted fever group (SFG) rickettsiae are recognized as important agents of emerging human tick-borne diseases worldwide. However, the epidemiology of rickettsial diseases has been poorly investigated in Romania. In urban habitats, companion animals which are frequently exposed to tick infestation, play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Therefore, the aim of the present study was to investigate the occurrence of SFG rickettsiae in ticks infesting dogs in a greater urban area in South-eastern Romania. Adult ixodid ticks (n=205), including Rhipicephalus sanguineus sensu lato (n=120), Dermacentor reticulatus (n=76) and Ixodes ricinus (n=9) were collected from naturally infested dogs and were screened for SFG rickettsiae using conventional PCR followed by sequencing. Additionally, ticks were screened for DNA of Babesia spp., Hepatozoon spp., Ehrlichia canis, and Anaplasma platys. Four zoonotic SFG rickettsiae were identified: Rickettsia raoultii (16%) and Rickettsia slovaca (3%) in D. reticulatus, Rickettsia monacensis (11%) in I. ricinus, and Rickettsia conorii (0.8%) in Rh. sanguineus s.l. Moreover, pathogens of veterinary importance, such as B. canis (21%) in D. reticulatus and E. canis (7.5%) in Rh. sanguineus s.l. were identified. The findings expand the knowledge on distribution of SFG rickettsiae as well as canine pathogens in Romania. Additionally, this is the first report describing the molecular detection of R. conorii in ticks from Romania. PMID:26507182

  15. The Rickettsia Endosymbiont of Ixodes pacificus Contains All the Genes of De Novo Folate Biosynthesis.

    PubMed

    Hunter, Daniel J; Torkelson, Jessica L; Bodnar, James; Mortazavi, Bobak; Laurent, Timothy; Deason, Jeff; Thephavongsa, Khanhkeo; Zhong, Jianmin

    2015-01-01

    Ticks and other arthropods often are hosts to nutrient providing bacterial endosymbionts, which contribute to their host's fitness by supplying nutrients such as vitamins and amino acids. It has been detected, in our lab, that Ixodes pacificus is host to Rickettsia species phylotype G021. This endosymbiont is predominantly present, and 100% maternally transmitted in I. pacificus. To study roles of phylotype G021 in I. pacificus, bioinformatic and molecular approaches were carried out. MUMmer genome alignments of whole genome sequence of I. scapularis, a close relative to I. pacificus, against completely sequenced genomes of R. bellii OSU85-389, R. conorii, and R. felis, identified 8,190 unique sequences that are homologous to Rickettsia sequences in the NCBI Trace Archive. MetaCyc metabolic reconstructions revealed that all folate gene orthologues (folA, folC, folE, folKP, ptpS) required for de novo folate biosynthesis are present in the genome of Rickettsia buchneri in I. scapularis. To examine the metabolic capability of phylotype G021 in I. pacificus, genes of the folate biosynthesis pathway of the bacterium were PCR amplified using degenerate primers. BLAST searches identified that nucleotide sequences of the folA, folC, folE, folKP, and ptpS genes possess 98.6%, 98.8%, 98.9%, 98.5% and 99.0% identity respectively to the corresponding genes of Rickettsia buchneri. Phylogenetic tree constructions show that the folate genes of phylotype G021 and homologous genes from various Rickettsia species are monophyletic. This study has shown that all folate genes exist in the genome of Rickettsia species phylotype G021 and that this bacterium has the genetic capability for de novo folate synthesis. PMID:26650541

  16. The Rickettsia Endosymbiont of Ixodes pacificus Contains All the Genes of De Novo Folate Biosynthesis

    PubMed Central

    Bodnar, James; Mortazavi, Bobak; Laurent, Timothy; Deason, Jeff; Thephavongsa, Khanhkeo; Zhong, Jianmin

    2015-01-01

    Ticks and other arthropods often are hosts to nutrient providing bacterial endosymbionts, which contribute to their host’s fitness by supplying nutrients such as vitamins and amino acids. It has been detected, in our lab, that Ixodes pacificus is host to Rickettsia species phylotype G021. This endosymbiont is predominantly present, and 100% maternally transmitted in I. pacificus. To study roles of phylotype G021 in I. pacificus, bioinformatic and molecular approaches were carried out. MUMmer genome alignments of whole genome sequence of I. scapularis, a close relative to I. pacificus, against completely sequenced genomes of R. bellii OSU85-389, R. conorii, and R. felis, identified 8,190 unique sequences that are homologous to Rickettsia sequences in the NCBI Trace Archive. MetaCyc metabolic reconstructions revealed that all folate gene orthologues (folA, folC, folE, folKP, ptpS) required for de novo folate biosynthesis are present in the genome of Rickettsia buchneri in I. scapularis. To examine the metabolic capability of phylotype G021 in I. pacificus, genes of the folate biosynthesis pathway of the bacterium were PCR amplified using degenerate primers. BLAST searches identified that nucleotide sequences of the folA, folC, folE, folKP, and ptpS genes possess 98.6%, 98.8%, 98.9%, 98.5% and 99.0% identity respectively to the corresponding genes of Rickettsia buchneri. Phylogenetic tree constructions show that the folate genes of phylotype G021 and homologous genes from various Rickettsia species are monophyletic. This study has shown that all folate genes exist in the genome of Rickettsia species phylotype G021 and that this bacterium has the genetic capability for de novo folate synthesis. PMID:26650541

  17. First report on the occurrence of Rickettsia slovaca and Rickettsia raoultii in Dermacentor silvarum in China

    PubMed Central

    2012-01-01

    Background Rickettsioses are among both the longest known and most recently recognized infectious diseases. Although new spotted fever group rickettsiae have been isolated in many parts of the world including China, Little is known about the epidemiology of Rickettsia pathogens in ticks from Xinjiang Autonomous Region of China. Methods In an attempt to assess the potential risk of rickettsial infection after exposure to ticks in Xinjiang Uygur Autonomous Region of China, a total of 200 Dermacentor silvarum ticks collected in Xinyuan district were screened by polymerase chain reaction based on the outer membrane protein A gene. Results 22 of the 200 specimens (11%) were found to be positive by PCR. Phylogenetic analysis of OmpA sequences identified two rickettsial species, Rickettsia raoultii (4.5%) and Rickettsia slovaca (6.5%). Conclusions This study has reported the occurrence of Rickettsia raoultii and Rickettsia slovaca in Xinjiang Autonomous Region of China and suggests that Dermacentor silvarum could be involved in the transmission of rickettsial agents in China. Further studies on the characterization and culture of rickettsial species found in Dermacentor silvarum should be performed to further clarify this. Additionally, the screening of human specimens for rickettsial disease in this region will define the incidence of infection. PMID:22257726

  18. Detection of Rickettsia and Anaplasma from hard ticks in Thailand.

    PubMed

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

    2015-12-01

    We collected a total of 169 adult hard ticks and 120 nymphs from under the leaves of plants located along tourist nature trails in ten localities. The results present data examining the vector competence of ticks of different genera and the presence of Rickettsia and Anaplasma species. The ticks belonged to three genera, Amblyomma, Dermacentor, and Haemaphysalis, comprising 11 species. Rickettsia bacteria were detected at three collection sites, while Anaplasma bacteria were detected at only one site. Phylogenetic analysis revealed new rickettsia genotypes from Thailand that were closely related to Rickettsia tamurae, Rickettsia monacensis, and Rickettsia montana. This study was also the first to show that Anaplasma bacteria are found in Haemaphysalis shimoga ticks and are closely related evolutionarily to Anaplasma bovis. These results provide additional information for the geographical distribution of tick species and tick-borne bacteria in Thailand and can therefore be applied for ecotourism management. PMID:26611960

  19. Possible Rickettsia massiliae Infection in Greece: an Imported Case.

    PubMed

    Chochlakis, Dimosthenis; Bongiorni, Christine; Partalis, Nikolaos; Tselentis, Yannis; Psaroulaki, Anna

    2016-07-22

    Tick-borne rickettsioses are endemic in Greece; however, until recently, only Rickettsia typhi and R. conorii were tested routinely in human samples arriving at the National Reference Center. During the last few years, the identification of different rickettsia species in ticks led to the introduction of other spotted fever group rickettsiae in routine analysis. Under the new scheme, R. massiliae is now tested routinely in human samples; herein, we describe a human case of this infection. PMID:26370425

  20. Detection of fibrils associated with Rickettsia rickettsii.

    PubMed Central

    Todd, W J; Burgdorfer, W; Wray, G P

    1983-01-01

    The ultrastructural appearance of the "halozone" formed at the interface between the spotted fever agent Rickettsia rickettsii and the cytoplasm of persistently infected cultured vole cells (Microtus pennsylvanicus) was studied by transmission electron microscopy. In sections of epoxy-embedded specimens stained with uranyl acetate and lead citrate, the halozone appeared clear and devoid of ultrastructural features. However, when unembedded preparations of whole infected cells were examined at 1,000 kV, fine structural features were observed within the halozone. These features, associated with the rickettsial outer membrane, were more clearly detectable when the infected cells were extracted with the detergent Triton X-100 before fixation. Under such conditions, long extensions of the rickettsial outer membrane, microfilament-like structures attached to that membrane, and extensive attachments between adjacent rickettsiae were seen. The fine structural features within the rickettsial halozone were also seen at 75 kV when unembedded sections were prepared from polyethylene glycol-embedded specimens. Thus, epoxy-embedding medium obscures the fine structural features within the halozone surrounding the rickettsiae in infected cells. Images PMID:6411620

  1. Phylogenetic Variants of Rickettsia africae, and Incidental Identification of "Candidatus Rickettsia Moyalensis" in Kenya

    PubMed Central

    Kimita, Gathii; Mutai, Beth; Nyanjom, Steven Ger; Wamunyokoli, Fred; Waitumbi, John

    2016-01-01

    Background Rickettsia africae, the etiological agent of African tick bite fever, is widely distributed in sub-Saharan Africa. Contrary to reports of its homogeneity, a localized study in Asembo, Kenya recently reported high genetic diversity. The present study aims to elucidate the extent of this heterogeneity by examining archived Rickettsia africae DNA samples collected from different eco-regions of Kenya. Methods To evaluate their phylogenetic relationships, archived genomic DNA obtained from 57 ticks a priori identified to contain R. africae by comparison to ompA, ompB and gltA genes was used to amplify five rickettsial genes i.e. gltA, ompA, ompB, 17kDa and sca4. The resulting amplicons were sequenced. Translated amino acid alignments were used to guide the nucleotide alignments. Single gene and concatenated alignments were used to infer phylogenetic relationships. Results Out of the 57 DNA samples, three were determined to be R. aeschlimanii and not R. africae. One sample turned out to be a novel rickettsiae and an interim name of “Candidatus Rickettsia moyalensis” is proposed. The bonafide R. africae formed two distinct clades. Clade I contained 9% of the samples and branched with the validated R. africae str ESF-5, while clade II (two samples) formed a distinct sub-lineage. Conclusions This data supports the use of multiple genes for phylogenetic inferences. It is determined that, despite its recent emergence, the R. africae lineage is diverse. This data also provides evidence of a novel Rickettsia species, Candidatus Rickettsia moyalensis. PMID:27387337

  2. Plasmids and Rickettsial Evolution: Insight from Rickettsia felis

    PubMed Central

    Gillespie, Joseph J.; Beier, Magda S.; Rahman, M. Sayeedur; Ammerman, Nicole C.; Shallom, Joshua M.; Purkayastha, Anjan; Sobral, Bruno S.; Azad, Abdu F.

    2007-01-01

    Background The genome sequence of Rickettsia felis revealed a number of rickettsial genetic anomalies that likely contribute not only to a large genome size relative to other rickettsiae, but also to phenotypic oddities that have confounded the categorization of R. felis as either typhus group (TG) or spotted fever group (SFG) rickettsiae. Most intriguing was the first report from rickettsiae of a conjugative plasmid (pRF) that contains 68 putative open reading frames, several of which are predicted to encode proteins with high similarity to conjugative machinery in other plasmid-containing bacteria. Methodology/Principal Findings Using phylogeny estimation, we determined the mode of inheritance of pRF genes relative to conserved rickettsial chromosomal genes. Phylogenies of chromosomal genes were in agreement with other published rickettsial trees. However, phylogenies including pRF genes yielded different topologies and suggest a close relationship between pRF and ancestral group (AG) rickettsiae, including the recently completed genome of R. bellii str. RML369-C. This relatedness is further supported by the distribution of pRF genes across other rickettsiae, as 10 pRF genes (or inactive derivatives) also occur in AG (but not SFG) rickettsiae, with five of these genes characteristic of typical plasmids. Detailed characterization of pRF genes resulted in two novel findings: the identification of oriV and replication termination regions, and the likelihood that a second proposed plasmid, pRFδ, is an artifact of the original genome assembly. Conclusion/Significance Altogether, we propose a new rickettsial classification scheme with the addition of a fourth lineage, transitional group (TRG) rickettsiae, that is unique from TG and SFG rickettsiae and harbors genes from possible exchanges with AG rickettsiae via conjugation. We offer insight into the evolution of a plastic plasmid system in rickettsiae, including the role plasmids may have played in the acquirement of

  3. High Seroprevalence for Typhus Group Rickettsiae, Southwestern Tanzania

    PubMed Central

    Dill, Tatjana; Dobler, Gerhard; Saathoff, Elmar; Clowes, Petra; Kroidl, Inge; Ntinginya, Elias; Machibya, Harun; Maboko, Leonard; Löscher, Thomas; Hoelscher, Michael

    2013-01-01

    Rickettsioses caused by typhus group rickettsiae have been reported in various African regions. We conducted a cross-sectional survey of 1,227 participants from 9 different sites in the Mbeya region, Tanzania; overall seroprevalence of typhus group rickettsiae was 9.3%. Risk factors identified in multivariable analysis included low vegetation density and highway proximity. PMID:23347529

  4. Importation of exotic ticks and tick-borne spotted fever group rickettsiae into the United States by migrating songbirds

    PubMed Central

    Mukherjee, Nabanita; Beati, Lorenza; Sellers, Michael; Burton, Laquita; Adamson, Steven; Robbins, Richard G.; Moore, Frank; Karim, Shahid

    2013-01-01

    Birds are capable of carrying ticks and, consequently, tick-transmitted microorganisms over long distances and across geographical barriers such as oceans and deserts. Ticks are hosts for several species of spotted fever group rickettsiae (SFGR), which can be transmitted to vertebrates during blood meals. In this study, the prevalence of this group of rickettsiae was examined in ticks infesting migratory songbirds by using polymerase chain reaction (PCR). During the 2009 and 2010 spring migration season, 2064 northward-migrating passerine songbirds were examined for ticks at Johnson Bayou, Louisiana. A total of 91 ticks was removed from 35 individual songbirds for tick species identification and spotted fever group rickettsia detection. Ticks were identified as Haemaphysalis juxtakochi (n=38, 42%), Amblyomma longirostre (n=22, 24%), Amblyomma nodosum (n=17, 19%), Amblyomma calcaratum (n=11, 12%), Amblyomma maculatum (n=2, 2%), and Haemaphysalis leporispalustris (n=1, 1%) by comparing their 12S rDNA gene sequence to homologous sequences in GenBank. Most of the identified ticks were exotic species originating outside of the United States. The phylogenetic analysis of the 71 ompA gene sequences of the rickettsial strains detected in the ticks revealed the occurrence of 6 distinct rickettsial genotypes. Two genotypes (corresponding to a total of 28 samples) were included in the Candidatus Rickettsia amblyommii clade (less than 1% divergence), 2 of them (corresponding to a total of 14 samples) clustered with Rickettsia sp. “Argentina” with less than 0.2% sequence divergence, and 2 of them (corresponding to a total of 27 samples), although closely related to the R. parkeri–R. africae lineage (2.50–3.41% divergence), exhibited sufficient genetic divergence from its members to possibly constitute a new rickettsial genotype. Overall, there does not seem to be a specific relationship between exotic tick species, the rickettsiae they harbor, or the reservoir

  5. STUDIES ON THE PHYSIOLOGY OF RICKETTSIAE V.

    PubMed Central

    Mallavia, L.; Paretsky, D.

    1963-01-01

    Mallavia, L. (University of Kansas, Lawrence) and D. Paretsky. Studies on the physiology of rickettsiae. V. Metabolism of carbamyl phosphate by Coxiella burnetii. J. Bacteriol. 86:232–238. 1963.—Preparations of disrupted Coxiella burnetii catalyze synthesis of citrulline from ornithine and carbamyl phosphate at an optimal pH of 7.0 to 7.5. Rickettsial synthesis of the pyrimidine precursor, ureidosuccinate, is demonstrated and confirmed by isolating C14-labeled ureidosuccinate from reaction mixtures of carbamyl phosphate and labeled aspartate. The data suggest a further rickettsial synthesis of orotate and imply rickettsial competence for host-independent pyrimidine synthesis. PMID:14058946

  6. Rickettsiae and Borrelia burgdorferi in ixodid ticks.

    PubMed Central

    Magnarelli, L A; Andreadis, T G; Stafford, K C; Holland, C J

    1991-01-01

    Nymphs and adults of hard-bodied ticks were collected in Connecticut and tested by direct and indirect immunofluorescence staining methods for rickettsiae and Borrelia burgdorferi. Of the 609 Ixodes dammini ticks examined, 59 (9.7%) harbored rickettsialike microorganisms in hemocytes (blood cells). These bacteria reacted with fluorescein-conjugated antiserum to Ehrlichia canis, the etiologic agent of with fluorescein-conjugated antiserum to Ehrlichia canis, the etiologic agent of canine ehrlichiosis. Prevalence of infection ranged from 6.8 to 12.7% for males and females, respectively. Although the specific identities of the hemocytic rickettsialike organisms are unknown, they share antigens with ehrlichiae. Electron microscopy revealed rickettsiae in ovarian tissues of I. dammini that also had infected hemocytes. Rickettsialike organisms were also observed in the hemocytes of 5 (6.9%) of 73 Dermacentor variabilis ticks. In analyses for B. burgdorferi, 146 (23.7%) of 617 I. dammini ticks harbored these spirochetes in midguts. Hemocytic rickettsialike microorganisms coexisted with B. burgdorferi in 36 (6.7%) of the 537 nymphs and adults of I. dammini examined. I. dammini, with its broad host range, has the potential to acquire multiple microorganisms. Images PMID:1757551

  7. Candidatus ‘Rickettsia senegalensis’ in cat fleas in Senegal

    PubMed Central

    Mediannikov, O.; Aubadie-Ladrix, M.; Raoult, D.

    2014-01-01

    Epidemiological studies of Rickettsia felis and related bacteria are very important, because the natural cycle of this important infection has not yet been established. The recent emergence of R. felis-associated febrile diseases in West and East Africa demands insightful epidemiological studies of the vectors and reservoirs of this bacterium in Africa. Twenty-nine cat fleas, Ctenocephalides felis, were tested for the presence of rickettsiae, including R. felis, bartonellae, and borreliae, with specific quantitative real-time PCR assays. Supporting our previous studies, R. felis was not detected in the fleas collected. In addition, neither Bartonella nor Borrelia was found. In five (17%) examined fleas, we found another species of rickettsia. We isolated three rickettsial strains, and genetic analysis demonstrated that these strains represent a probable new species, provisionally called Candidatus Rickettsia senegalensis here. PMID:25755888

  8. Zoonotic surveillance for rickettsiae in domestic animals in Kenya.

    PubMed

    Mutai, Beth K; Wainaina, James M; Magiri, Charles G; Nganga, Joseph K; Ithondeka, Peter M; Njagi, Obadiah N; Jiang, Ju; Richards, Allen L; Waitumbi, John N

    2013-06-01

    Abstract Rickettsiae are obligate intracellular bacteria that cause zoonotic and human diseases. Arthropod vectors, such as fleas, mites, ticks, and lice, transmit rickettsiae to vertebrates during blood meals. In humans, the disease can be life threatening. This study was conducted amidst rising reports of rickettsioses among travelers to Kenya. Ticks and whole blood were collected from domestic animals presented for slaughter at major slaughterhouses in Nairobi and Mombasa that receive animals from nearly all counties in the country. Blood samples and ticks were collected from 1019 cattle, 379 goats, and 299 sheep and were screened for rickettsiae by a quantitative PCR (qPCR) assay (Rick17b) using primers and probe that target the genus-specific 17-kD gene (htrA). The ticks were identified using standard taxonomic keys. All Rick17b-positive tick DNA samples were amplified and sequenced with primers sets that target rickettsial outer membrane protein genes (ompA and ompB) and the citrate-synthase encoding gene (gltA). Using the Rick17b qPCR, rickettsial infections in domestic animals were found in 25/32 counties sampled (78.1% prevalence). Infection rates were comparable in cattle (16.3%) and sheep (15.1%) but were lower in goats (7.1%). Of the 596 ticks collected, 139 had rickettsiae (23.3%), and the detection rates were highest in Amblyomma (62.3%; n=104), then Rhipicephalus (45.5%; n=120), Hyalomma (35.9%; n=28), and Boophilus (34.9%; n=30). Following sequencing, 104 out of the 139 Rick17b-positive tick DNA had good reverse and forward sequences for the 3 target genes. On querying GenBank with the generated consensus sequences, homologies of 92-100% for the following spotted fever group (SFG) rickettsiae were identified: Rickettsia africae (93.%, n=97), Rickettsia aeschlimannii (1.9%, n=2), Rickettsia mongolotimonae (0.96%, n=1), Rickettsia conorii subsp. israelensis (0.96%, n=1), Candidatus Rickettsia kulagini (0.96% n=1), and Rickettsia spp. (1.9% n=2). In

  9. Dynamics of the endosymbiont Rickettsia in an insect pest.

    PubMed

    Cass, Bodil N; Yallouz, Rachel; Bondy, Elizabeth C; Mozes-Daube, Netta; Horowitz, A Rami; Kelly, Suzanne E; Zchori-Fein, Einat; Hunter, Martha S

    2015-07-01

    A new heritable bacterial association can bring a fresh set of molecular capabilities, providing an insect host with an almost instantaneous genome extension. Increasingly acknowledged as agents of rapid evolution, inherited microbes remain underappreciated players in pest management programs. A Rickettsia bacterium was tracked sweeping through populations of an invasive whitefly provisionally described as the "B" or "MEAM1" of the Bemisia tabaci species complex, in the southwestern USA. In this population, Rickettsia provides strong fitness benefits and distorts whitefly sex ratios under laboratory conditions. In contrast, whiteflies in Israel show few apparent fitness benefits from Rickettsia under laboratory conditions, only slightly decreasing development time. A survey of B. tabaci B samples revealed the distribution of Rickettsia across the cotton-growing regions of Israel and the USA. Thirteen sites from Israel and 22 sites from the USA were sampled. Across the USA, Rickettsia frequencies were heterogeneous among regions, but were generally very high, whereas in Israel, the infection rates were lower and declining. The distinct outcomes of Rickettsia infection in these two countries conform to previously reported phenotypic differences. Intermediate frequencies in some areas in both countries may indicate a cost to infection in certain environments or that the frequencies are in flux. This suggests underlying geographic differences in the interactions between bacterial symbionts and this serious agricultural pest. PMID:25626393

  10. Rickettsia species in fleas collected from small mammals in Slovakia.

    PubMed

    Špitalská, Eva; Boldiš, Vojtech; Mošanský, Ladislav; Sparagano, Olivier; Stanko, Michal

    2015-11-01

    Epidemiological and epizootiological studies of Rickettsia felis and other Rickettsia spp. are very important, because their natural cycle has not yet been established completely. In total, 315 fleas (Siphonaptera) of 11 species of Ceratophyllidae, Hystrichopsyllidae and Leptopsyllidae families were tested for the presence of Rickettsia species and Coxiella burnetii with conventional and specific quantitative real-time PCR assays. Fleas were collected from five rodent hosts (Myodes glareolus, Apodemus flavicollis, Apodemus agrarius, Microtus subterraneus, Microtus arvalis) and three shrew species (Sorex araneus, Neomys fodiens, Crocidura suaveolens) captured in Eastern and Southern Slovakia. Overall, Rickettsia spp. was found in 10.8% (34/315) of the tested fleas of Ctenophthalmus agyrtes, Ctenophthalmus solutus, Ctenophthalmus uncinatus and Nosopsyllus fasciatus species. Infected fleas were coming from A. flavicollis, A. agrarius, and M. glareolus captured in Eastern Slovakia. C. burnetii was not found in any fleas. R. felis, Rickettsia helvetica, unidentified Rickettsia, and rickettsial endosymbionts were identified in fleas infesting small mammals in the Košice region, Eastern Slovakia. This study is the first report of R. felis infection in C. solutus male flea collected from A. agrarius in Slovakia. PMID:26346455

  11. Human Infections by Multiple Spotted Fever Group Rickettsiae in Tennessee.

    PubMed

    Delisle, Josie; Mendell, Nicole L; Stull-Lane, Annica; Bloch, Karen C; Bouyer, Donald H; Moncayo, Abelardo C

    2016-06-01

    Rocky Mountain spotted fever is the most common tick-borne disease in Tennessee. However, Rickettsia rickettsii has rarely been isolated from endemic ticks, suggesting rickettsioses may be caused by other species. A total of 56 human serum samples that were serologically positive for exposure to Rickettsia were obtained from commercial laboratories in 2010 and 2011. In addition, 20 paired sera from patients with encephalitis and positive Rickettsia serology were obtained from the Tennessee Unexplained Encephalitis Surveillance (TUES) study. Using an immunofluorescence assay, reactivity of the sera to R. rickettsii, Rickettsia montanensis, Rickettsia parkeri, and Rickettsia amblyommii was tested, and a comparison of endpoint titers was used to determine the probable antigen that stimulated the antibody response. Cross-absorption was conducted for 94.8% (N = 91) of the samples due to serologic cross-reactivity. Of the commercial laboratory samples, 55.4% (N = 31) had specific reactivity to R. amblyommii and 44.6% (N = 25) were indeterminate. Of the paired TUES samples, 20% (N = 4) had specific reactivity to R. amblyommii, 5% (N = 1) to R. montanensis, and 5% (N = 1) to R. parkeri Patients with specific reactivity to R. amblyommii experienced fever (75%), headache (68%) and myalgia (58%). Rash (36%) and thrombocytopenia (40%) were less common. To our knowledge, this is the first time R. amblyommii has been reported as a possible causative agent of rickettsioses in Tennessee. PMID:27022147

  12. Rickettsia massiliae and Rickettsia conorii Israeli Spotted Fever Strain Differentially Regulate Endothelial Cell Responses

    PubMed Central

    Bechelli, Jeremy; Smalley, Claire; Milhano, Natacha; Walker, David H.; Fang, Rong

    2015-01-01

    Rickettsiae primarily target microvascular endothelial cells. However, it remains elusive how endothelial cell responses to rickettsiae play a role in the pathogenesis of rickettsial diseases. In the present study, we employed two rickettsial species with high sequence homology but differing virulence to investigate the pathological endothelial cell responses. Rickettsia massiliae is a newly documented human pathogen that causes a mild spotted fever rickettsiosis. The “Israeli spotted fever” strain of R. conorii (ISF) causes severe disease with a mortality rate up to 30% in hospitalized patients. At 48 hours post infection (HPI), R. conorii (ISF) induced a significant elevation of IL-8 and IL-6 while R. massiliae induced a statistically significant elevated amount of MCP-1 at both transcriptional and protein synthesis levels. Strikingly, R. conorii (ISF), but not R. massiliae, caused a significant level of cell death or injury in HMEC-1 cells at 72 HPI, demonstrated by live-dead cell staining, annexin V staining and lactate dehydrogenase release. Monolayers of endothelial cells infected with R. conorii (ISF) showed a statistically significant decrease in electrical resistance across the monolayer compared to both R. massiliae-infected and uninfected cells at 72 HPI, suggesting increased endothelial permeability. Interestingly, pharmacological inhibitors of caspase-1 significantly reduced the release of lactate dehydrogenase by R. conorii (ISF)-infected HMEC-1 cells, which suggests the role of caspase-1 in mediating the death of endothelial cells. Taken together, our data illustrated that a distinct proinflammatory cytokine profile and endothelial dysfunction, as evidenced by endothelial cell death/injury and increased permeability, are associated with the severity of rickettsial diseases. PMID:26394396

  13. Molecular Evidence of Different Rickettsia Species in Villeta, Colombia.

    PubMed

    Faccini-Martínez, Álvaro A; Ramírez-Hernández, Alejandro; Forero-Becerra, Elkin; Cortés-Vecino, Jesús A; Escandón, Patricia; Rodas, Juan D; Palomar, Ana M; Portillo, Aránzazu; Oteo, José A; Hidalgo, Marylin

    2016-02-01

    The aim of this work was to detect and identify Rickettsia species in ticks collected in rural areas of Villeta, Colombia. Tick specimens were collected from domestic animals and walls of houses in five rural villages of Villeta town and from humans in Naranjal village (same town). Moreover, a flea collected from the same area was also processed. DNA was extracted and tested by conventional, semi-nested, and nested PCR reactions targeting rickettsial genes. In the ticks collected from humans from Naranjal village, a nymph of Amblyomma cajennense sensu lato was amplified using primers for ompA and sequenced (100% identity with "Candidatus Rickettsia amblyommii"). Last, three amplicons from the Ctenocephalides felis flea, corresponding to gltA, ompB, and 16S rRNA genes, showed high identity with R. felis (98.5%, 97.3%, and 99.2%, respectively) and "Candidatus Rickettsia asemboensis" (99.7% and 100%, respectively). To our knowledge, these results correspond to the first molecular detection in Colombia of "Candidatus Rickettsia amblyommii" and "Ca. Rickettsia asemboensis" in fleas. PMID:26789730

  14. A Case of Human Infection by Rickettsia slovaca in Greece.

    PubMed

    Kostopoulou, Vasiliki; Chochlakis, Dimosthenis; Kanta, Chrysoula; Katsanou, Andromachi; Rossiou, Konstantina; Rammos, Aidonis; Papadopoulos, Spyridon-Filippos; Katsarou, Theodora; Tselentis, Yannis; Psaroulaki, Anna; Boukas, Chrysostomos

    2016-07-22

    Although tick-borne rickettsiosis is endemic in Greece, until recently, human samples arriving at the National Reference Centre under suspicion of rickettsial infection were routinely tested only for Rickettsia typhi and R. conorii. However, identification of additional rickettsia species in ticks prompted revision of the protocol in 2010. Until that year, all human samples received by the laboratory were tested for antibodies against R. conorii and R. typhi only. Now, tests for R. slovaca, R. felis, and R. mongolotimonae are all included in routine analysis. The current description of a human R. slovaca case is possible as a result of these changes in routine testing. PMID:26370429

  15. Which Way In? The RalF Arf-GEF Orchestrates Rickettsia Host Cell Invasion

    PubMed Central

    Rennoll-Bankert, Kristen E.; Rahman, M. Sayeedur; Gillespie, Joseph J.; Guillotte, Mark L.; Kaur, Simran J.; Lehman, Stephanie S.; Beier-Sexton, Magda; Azad, Abdu F.

    2015-01-01

    Bacterial Sec7-domain-containing proteins (RalF) are known only from species of Legionella and Rickettsia, which have facultative and obligate intracellular lifestyles, respectively. L. pneumophila RalF, a type IV secretion system (T4SS) effector, is a guanine nucleotide exchange factor (GEF) of ADP-ribosylation factors (Arfs), activating and recruiting host Arf1 to the Legionella-containing vacuole. In contrast, previous in vitro studies showed R. prowazekii (Typhus Group) RalF is a functional Arf-GEF that localizes to the host plasma membrane and interacts with the actin cytoskeleton via a unique C-terminal domain. As RalF is differentially encoded across Rickettsia species (e.g., pseudogenized in all Spotted Fever Group species), it may function in lineage-specific biology and pathogenicity. Herein, we demonstrate RalF of R. typhi (Typhus Group) interacts with the Rickettsia T4SS coupling protein (RvhD4) via its proximal C-terminal sequence. RalF is expressed early during infection, with its inactivation via antibody blocking significantly reducing R. typhi host cell invasion. For R. typhi and R. felis (Transitional Group), RalF ectopic expression revealed subcellular localization with the host plasma membrane and actin cytoskeleton. Remarkably, R. bellii (Ancestral Group) RalF showed perinuclear localization reminiscent of ectopically expressed Legionella RalF, for which it shares several structural features. For R. typhi, RalF co-localization with Arf6 and PI(4,5)P2 at entry foci on the host plasma membrane was determined to be critical for invasion. Thus, we propose recruitment of PI(4,5)P2 at entry foci, mediated by RalF activation of Arf6, initiates actin remodeling and ultimately facilitates bacterial invasion. Collectively, our characterization of RalF as an invasin suggests that, despite carrying a similar Arf-GEF unknown from other bacteria, different intracellular lifestyles across Rickettsia and Legionella species have driven divergent roles for Ral

  16. Prevalence of antibodies to Rickettsiae in different regions of Serbia.

    PubMed

    Samardzic, Svetomir; Marinkovic, Tatjana; Marinkovic, Dragan; Djuricic, Bosiljka; Ristanovic, Elizabeta; Simovic, Tatjana; Lako, Branislav; Vukov, Biljana; Bozovic, Bojana; Gligic, Ana

    2008-04-01

    We assayed the presence of antibodies specific for Rickettsia typhi, R. akari, and R. conorii in sera of persons from several localities in Serbia with different geographic, climatic, and lifestyle characteristics. Sera from 140 patients with unclear clinical symptoms and 273 healthy persons were tested for the presence of rickettsiae-specific antibodies by indirect immunofluorescence assay. In this study, for the first time we detected the presence of rickettsiae from the spotted fever group in Serbia. We detected the presence of antibodies against R. conorii in the samples from all tested localities. The proportion of positive cases was low in the plain agricultural areas but reached up to 23% in the mountain areas. We also observed a significant number of cases positive for antibodies against R. akari. Antibodies specific for the antigens of R. typhi were detected in only 2 samples from the municipality of Pec (Kosovo region). These findings contribute to the prevalence of Rickettsia species in Southeast Europe. Our study also revealed a dramatic lack of awareness of rickettsioses among medical personnel and pointed to the need for urgent measures that would help improve the current situation in the region. PMID:18240971

  17. Rickettsia sibirica mongolitimonae Infection, France, 2010–2014

    PubMed Central

    Angelakis, Emmanouil; Richet, Herve

    2016-01-01

    To further characterize human infections caused by Rickettsia sibirica mongolitimonae, we tested skin biopsy and swab samples and analyzed clinical, epidemiologic, and diagnostic characteristics of patients with a rickettsiosis. The most common (38%) indigenous species was R. sibirica mongolitimonae. Significantly more cases of R. sibirica mongolitimonae infection occurred during spring and summer. PMID:27088367

  18. Genome Sequence of the Tick-Borne Pathogen Rickettsia raoultii

    PubMed Central

    El Karkouri, Khalid; Mediannikov, Oleg; Robert, Catherine; Raoult, Didier

    2016-01-01

    Rickettsia raoultii is a tick-associated spotted fever group (SFG) organism, causing scalp eschar and neck lymphadenopathy after tick bite (SENLAT) in humans. We report here the genome sequence of R. raoultii strain KhabarovskT (CSUR R3T, ATCC VR-1596T), which was isolated from a Dermacentor silvarum tick collected in Russia. PMID:27103706

  19. Genome Sequence of the Tick-Borne Pathogen Rickettsia raoultii.

    PubMed

    El Karkouri, Khalid; Mediannikov, Oleg; Robert, Catherine; Raoult, Didier; Fournier, Pierre-Edouards

    2016-01-01

    ITALIC! Rickettsia raoultiiis a tick-associated spotted fever group (SFG) organism, causing scalp eschar and neck lymphadenopathy after tick bite (SENLAT) in humans. We report here the genome sequence of ITALIC! R. raoultiistrain Khabarovsk(T)(CSUR R3(T), ATCC VR-1596(T)), which was isolated from a ITALIC! Dermacentor silvarumtick collected in Russia. PMID:27103706

  20. Human infection with Rickettsia sibirica mongolitimonae, Spain, 2007-2011.

    PubMed

    Ramos, José M; Jado, Isabel; Padilla, Sergio; Masiá, Mar; Anda, Pedro; Gutiérrez, Félix

    2013-02-01

    Human infection with Rickettsia sibirica mongolitimonae was initially reported in 1996, and reports of a total of 18 cases have been published. We describe 6 additional cases that occurred in the Mediterranean coast region of Spain during 2007-2011. Clinicians should consider this infection in patients who have traveled to this area. PMID:23343524

  1. Abducens Nerve Palsy and Meningitis by Rickettsia typhi

    PubMed Central

    Moy, Wai Lun; Ooi, Say Tat

    2015-01-01

    Patients with rickettsial infection may present with encephalitis or meningitis but neurologic involvement is rare in murine typhus. Here, we report two patients with Rickettsia typhi meningitis who presented with cranial neuropathy, presumably caused by two distinct disease processes. Recognition of the disease manifestations is important because rickettsial infections are potentially associated with significant morbidity. Simple effective treatments are available. PMID:25548377

  2. 21 CFR 866.3500 - Rickettsia serological reagents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rickettsia serological reagents. 866.3500 Section 866.3500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3500...

  3. 21 CFR 866.3500 - Rickettsia serological reagents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Rickettsia serological reagents. 866.3500 Section 866.3500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3500...

  4. 21 CFR 866.3500 - Rickettsia serological reagents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Rickettsia serological reagents. 866.3500 Section 866.3500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3500...

  5. 21 CFR 866.3500 - Rickettsia serological reagents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Rickettsia serological reagents. 866.3500 Section 866.3500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3500...

  6. 21 CFR 866.3500 - Rickettsia serological reagents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Rickettsia serological reagents. 866.3500 Section 866.3500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3500...

  7. 'Candidatus Rickettsia mendelii', a novel basal group rickettsia detected in Ixodes ricinus ticks in the Czech Republic.

    PubMed

    Hajduskova, Eva; Literak, Ivan; Papousek, Ivo; Costa, Francisco B; Novakova, Marketa; Labruna, Marcelo B; Zdrazilova-Dubska, Lenka

    2016-04-01

    A novel rickettsial sequence in the citrate synthase gltA gene indicating a novel Rickettsia species has been detected in 7 out of 4524 Ixodes ricinus ticks examined within several surveys performed in the Czech Republic from 2005 to 2009. This new Candidatus Rickettsia sp. sequence has been found in 2 nymphs feeding on wild birds (Luscinia megarhynchos and Erithacus rubecula), in a male tick from vegetation, and 4 ticks feeding on a dog (3 males, 1 female tick). Portions of the ompA, ompB, sca4, and htrA genes were not amplifiable in these samples. A maximum likelihood tree of rickettsiae based on comparisons of partial amino acid sequences of citrate synthase and nucleotide sequences of 16S rDNA genes and phylogenetic analysis revealed a basal position of the novel species in the proximity of R. bellii and R. canadensis. The novel species has been named 'Candidatus Rickettsia mendelii' after the founder of genetics, Gregor Mendel. PMID:26873811

  8. Flying squirrel-associated Rickettsia prowazekii (epidemic typhus rickettsiae) characterized by a specific DNA fragment produced by restriction endonuclease digestion.

    PubMed

    Regnery, R L; Fu, Z Y; Spruill, C L

    1986-01-01

    The DNA from flying squirrel-associated Rickettsia prowazekii was characterized by using a specific DNA fragment produced by digestion with the enzyme BamHI. The DNA fragment was cloned into a plasmid vector and used to readily distinguish between available human- and flying squirrel-associated R. prowazekii DNAs derived from crude cytoplasmic extracts. PMID:3009528

  9. Detection of “Candidatus Rickettsia sp. strain Argentina”and Rickettsia bellii in Amblyomma ticks (Acari: Ixodidae) from Northern Argentina

    PubMed Central

    Tomassone, L.; Nuñez, P.; Ceballos, L. A.; Gürtler, R. E.; Kitron, U.; Farber, M.

    2011-01-01

    Ixodid ticks were collected from vegetation and from humans, wild and domestic mammals in a rural area in the semi-arid Argentine Chaco in late spring 2006 to evaluate their potential role as vectors of Spotted Fever Group (SFG) rickettsiae. A total of 233 adult ticks, identified as Amblyomma parvum, Amblyomma tigrinum and Amblyomma pseudoconcolor, was examined for Rickettsia spp. We identified an SFG rickettsia of unknown pathogenicity, “Candidatus Rickettsia sp. strain Argentina”, in A. parvum and A. pseudoconcolor by PCR assays targeting gltA, ompA, ompB and 17-kDa outer membrane antigen rickettsial genes. Rickettsia bellii was detected in a host-seeking male of A. tigrinum. Amblyomma parvum is widespread in the study area and is a potential threat to human health. PMID:20186466

  10. Rickettsia Phylogenomics: Unwinding the Intricacies of Obligate Intracellular Life

    PubMed Central

    Gillespie, Joseph J.; Williams, Kelly; Shukla, Maulik; Snyder, Eric E.; Nordberg, Eric K.; Ceraul, Shane M.; Dharmanolla, Chitti; Rainey, Daphne; Soneja, Jeetendra; Shallom, Joshua M.; Vishnubhat, Nataraj Dongre; Wattam, Rebecca; Purkayastha, Anjan; Czar, Michael; Crasta, Oswald; Setubal, Joao C.; Azad, Abdu F.; Sobral, Bruno S.

    2008-01-01

    Background Completed genome sequences are rapidly increasing for Rickettsia, obligate intracellular α-proteobacteria responsible for various human diseases, including epidemic typhus and Rocky Mountain spotted fever. In light of phylogeny, the establishment of orthologous groups (OGs) of open reading frames (ORFs) will distinguish the core rickettsial genes and other group specific genes (class 1 OGs or C1OGs) from those distributed indiscriminately throughout the rickettsial tree (class 2 OG or C2OGs). Methodology/Principal Findings We present 1823 representative (no gene duplications) and 259 non-representative (at least one gene duplication) rickettsial OGs. While the highly reductive (∼1.2 MB) Rickettsia genomes range in predicted ORFs from 872 to 1512, a core of 752 OGs was identified, depicting the essential Rickettsia genes. Unsurprisingly, this core lacks many metabolic genes, reflecting the dependence on host resources for growth and survival. Additionally, we bolster our recent reclassification of Rickettsia by identifying OGs that define the AG (ancestral group), TG (typhus group), TRG (transitional group), and SFG (spotted fever group) rickettsiae. OGs for insect-associated species, tick-associated species and species that harbor plasmids were also predicted. Through superimposition of all OGs over robust phylogeny estimation, we discern between C1OGs and C2OGs, the latter depicting genes either decaying from the conserved C1OGs or acquired laterally. Finally, scrutiny of non-representative OGs revealed high levels of split genes versus gene duplications, with both phenomena confounding gene orthology assignment. Interestingly, non-representative OGs, as well as OGs comprised of several gene families typically involved in microbial pathogenicity and/or the acquisition of virulence factors, fall predominantly within C2OG distributions. Conclusion/Significance Collectively, we determined the relative conservation and distribution of 14354 predicted

  11. Detection of spotted fever group Rickettsia spp. from bird ticks in the U.K.

    PubMed

    Graham, R I; Mainwaring, M C; Du Feu, R

    2010-09-01

    Migratory birds are known to play a role in the long-distance transportation of microorganisms. To investigate whether this is true for rickettsial agents, we undertook a study to characterize tick infestation in populations of the migratory passerine bird Riparia riparia (Passeriformes: Hirundinidae), the sand martin. A total of 194 birds were sampled and ticks removed from infested birds. The ticks were identified as female Ixodes lividus (Acari: Ixodidae) using standard morphological and molecular techniques. Tick DNA was assayed to detect Rickettsia spp. using polymerase chain reaction and DNA was sequenced for species identification. A single Rickettsia spp. was detected in 100% of the ticks and was designated Rickettsia sp. IXLI1. Partial sequences of 17-kDa and ompA genes showed greatest similarity to Rickettsia sp. TCM1, an aetiological agent of Japanese spotted fever-like illness, previously described in Thailand. Phylogenetic analysis showed that Rickettsia sp. IXLI1 fitted neatly into a group containing strains Rickettsia japonica, Rickettsia sp. strain Davousti and Rickettsia heilongjiangensis. In conclusion, this research shows that U.K. migratory passerine birds host ticks infected with Rickettsia species and contribute to the geographic distribution of spotted fever rickettsial agents. PMID:20546129

  12. Rickettsia infection in Amblyomma tonelliae, a tick species from the Amblyomma cajennense complex.

    PubMed

    Tarragona, Evelina L; Cicuttin, Gabriel L; Mangold, Atilio J; Mastropaolo, Mariano; Nazarena De Salvo, M; Nava, Santiago

    2015-03-01

    The present study was performed to evaluate the Rickettsia infection in Amblyomma tonelliae ticks from Argentina. All ticks were subjected to DNA extraction and tested by a battery of PCRs to amplify fragments of four rickettsial genes, 23S-5S, gltA, ompA and htrA. Two ticks were positive. The Rickettsia detected in one tick represents a new lineage which is named Rickettsia sp. strain El Tunal. This new strain belongs to the canadensis group because it is closely related to Rickettsia monteiroi, Rickettsia canadensis and Candidatus "Rickettsia tarasevichiae". They clustered together on a high supported clade with both gltA and htrA genes. The other positive tick was infected with Candidatus "Rickettsia amblyommii". The results presented in this study constitute the first records of Rickettsia infection in A. tonelliae ticks. However, the medical relevance of these findings should be considered cautiously because the pathogenicity of Rickettsia sp. strain El Tunal and Candidatus "R. amblyommii" remains undetermined. PMID:25544308

  13. Detection of a novel Rickettsia (Alphaproteobacteria: Rickettsiales) in rotund ticks (Ixodes kingi) from Saskatchewan, Canada.

    PubMed

    Anstead, Clare A; Chilton, Neil B

    2013-04-01

    A novel Rickettsia was detected in the rotund tick, Ixodes kingi Bishopp, 1911, based on comparative DNA sequence analyses of 4 genes; the rickettsial-specific 17-kDa antigen gene, citrate synthase gene (gltA), the outer surface membrane protein A gene (ompA), and the 16S rRNA gene. The rickettsiae in I. kingi differed in nucleotide sequence from those of other Rickettsia species by 5.8-18.3% for the 17-kDa gene, 0.9-13.9% for gltA, 5.5-22.8% for ompA, and 0.9-1.6% for the 16S rRNA gene. Phylogenetic analyses of the sequence data revealed that this putative new species of Rickettsia, provisionally named Candidatus Rickettsia kingi, does not belong to the spotted fever group or typhus group of rickettsiae, but represents a sister taxon to R. canadensis and Candidatus Rickettsia tarasevichiae. This novel Rickettsia was found in 60 of the 87 (69%) ticks examined, which included all feeding life cycle stages of I. kingi. Although adult I. kingi occasionally parasitize dogs and humans, it remains to be determined if this Rickettsia is pathogenic to these host species. PMID:23419865

  14. Human endothelial cell culture plaques induced by Rickettsia rickettsii.

    PubMed Central

    Walker, D H; Firth, W T; Edgell, C J

    1982-01-01

    Primary cultures of human umbilical vein endothelial cells were inoculated with plaque-purified Rickettsia rickettsii. After adsorption of rickettsiae, monolayers were overlaid with medium containing 0.5% agarose. Small plaques appeared on day 4 postinoculation, and distinct 1- to 2-mm plaques were observed on day 5. Plaquing efficiency was less than that of primary chicken embryo cells in the same medium. Human endothelial cell monolayers were susceptible to infection by R. rickettsii and underwent necrosis as demonstrated by supravital staining. The topographic association of endothelial cell necrosis and rickettsial infection in the plaque model confirmed the direct cytopathic effect of R. rickettsii on human endothelium. Uninfected cells appeared normal by supravital staining and transmission electron microscopy. This model offers the possibility of investigating rickettsial pathogenesis and mechanisms of enhanced severity of Rocky Mountain spotted fever in specific genetically determined conditions. Images PMID:6809631

  15. Identification of an isolate of Rickettsia canada from California.

    PubMed

    Philip, R N; Casper, E A; Anacker, R L; Peacock, M G; Hayes, S F; Lane, R S

    1982-11-01

    A strain of Rickettsia canada was recovered in 1980 an adult rabbit tick, Haemaphysalis leporispalustris, taken from a black-tailed jack rabbit, Lepus californicus, in Mendocino County, California. In all examined biologic characteristics, this isolate, CA410, is indistinguishable from the prototype, strain 2678, isolated in Ontario, Canada, in 1963. These similarities include serologic and immunologic reactivity in laboratory mice and guinea pigs, cultural characteristics in Vero cells, chick embryo cells and embryonated eggs, low pathogenicity for mice, meadow voles and guinea pigs, unusual resistance to streptomycin, morphology by electron microscopy, and molar percentages of guanine plus cytosine of the deoxyribonucleic acids. Recovery of this second strain in the same species of tick, but far removed in time and place from the origin of the prototype, provides evidence that R. canada is an established, ecologically stable, rickettsia in North America. PMID:6756179

  16. Rickettsia australis Activates Inflammasome in Human and Murine Macrophages

    PubMed Central

    Smalley, Claire; Bechelli, Jeremy; Rockx-Brouwer, Dedeke; Saito, Tais; Azar, Sasha R.; Ismail, Nahed; Walker, David H.; Fang, Rong

    2016-01-01

    Rickettsiae actively escape from vacuoles and replicate free in the cytoplasm of host cells, where inflammasomes survey the invading pathogens. In the present study, we investigated the interactions of Rickettsia australis with the inflammasome in both mouse and human macrophages. R. australis induced a significant level of IL-1β secretion by human macrophages, which was significantly reduced upon treatment with an inhibitor of caspase-1 compared to untreated controls, suggesting caspase-1-dependent inflammasome activation. Rickettsia induced significant secretion of IL-1β and IL-18 in vitro by infected mouse bone marrow-derived macrophages (BMMs) as early as 8–12 h post infection (p.i.) in a dose-dependent manner. Secretion of these cytokines was accompanied by cleavage of caspase-1 and was completely abrogated in BMMs deficient in caspase-1/caspase-11 or apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC), suggesting that R. australis activate the ASC-dependent inflammasome. Interestingly, in response to the same quantity of rickettsiae, NLRP3-/- BMMs significantly reduced the secretion level of IL-1β compared to wild type (WT) controls, suggesting that NLRP3 inflammasome contributes to cytosolic recognition of R. australis in vitro. Rickettsial load in spleen, but not liver and lung, of R. australis-infected NLRP3-/- mice was significantly greater compared to WT mice. These data suggest that NLRP3 inflammasome plays a role in host control of bacteria in vivo in a tissue-specific manner. Taken together, our data, for the first time, illustrate the activation of ASC-dependent inflammasome by R. australis in macrophages in which NLRP3 is involved. PMID:27362650

  17. Detection of Rickettsia bellii and Rickettsia amblyommii in Amblyomma longirostre (Acari: Ixodidae) from Bahia state, Northeast Brazil.

    PubMed

    McIntosh, Douglas; Bezerra, Rodrigo Alves; Luz, Hermes Ribeiro; Faccini, João Luiz Horacio; Gaiotto, Fernanda Amato; Giné, Gastón Andrés Fernandez; Albuquerque, George Rego

    2015-01-01

    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. PMID:26413074

  18. Detection of Rickettsia bellii and Rickettsia amblyommii in Amblyomma longirostre (Acari: Ixodidae) from Bahia state, Northeast Brazil

    PubMed Central

    McIntosh, Douglas; Bezerra, Rodrigo Alves; Luz, Hermes Ribeiro; Faccini, João Luiz Horacio; Gaiotto, Fernanda Amato; Giné, Gastón Andrés Fernandez; Albuquerque, George Rego

    2015-01-01

    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

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

    PubMed Central

    Eremeeva, Marina E.; Dasch, Gregory A.

    2015-01-01

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

  20. Rickettsioses in Europe.

    PubMed

    Portillo, Aránzazu; Santibáñez, Sonia; García-Álvarez, Lara; Palomar, Ana M; Oteo, José A

    2015-01-01

    Bacteria of the genera Rickettsia and Orientia (family rickettsiaceae, order rickettsiales) cause rickettsioses worldwide, and are transmitted by lice, fleas, ticks and mites. In Europe, only Rickettsia spp. cause rickettsioses. With improvement of hygiene, the risk of louse-borne rickettsiosis (epidemic typhus) is low in Europe. Nevertheless, recrudescent form of Rickettsia prowazekii infection persists. There could be an epidemic typhus outbreak if a body lice epidemic occurs under unfavorable sanitary conditions. In Europe, endemic typhus or Rickettsia typhi infection, transmitted by rats and fleas, causes febrile illness. At the beginning of this century, flea-borne spotted fever cases caused by Rickettsia felis were diagnosed. Flea-borne rickettsiosis should be suspected after flea bites if fever, with or without rash, is developed. Tick-borne rickettsioses are the main source of rickettsia infections in Europe. Apart from Rickettsia conorii, the Mediterranean Spotted Fever (MSF) agent, other Rickettsia spp. cause MSF-like: Rickettsia helvetica, Rickettsia monacensis, Rickettsia massiliae or Rickettsia aeschlimannii. In the 1990s, two 'new' rickettsioses were diagnosed: Lymphangitis Associated Rickettsiosis (LAR) caused by Rickettsia sibirica mongolitimonae, and Tick-Borne Lymphadenopathy/Dermacentor-Borne-Necrosis-Erythema-Lymphadenopathy/Scalp Eschar Neck Lymphadenopathy (TIBOLA/DEBONEL/SENLAT), caused by Rickettsia slovaca, Candidatus Rickettsia rioja and Rickettsia raoultii. Lastly, European reports about mite-borne rickettsiosis are scarce. PMID:26384814

  1. Serological evidence of typhus group Rickettsia in a homeless population: Houston, Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sera from 176 homeless people in Houston was tested for antibodies against typhus group rickettsiae (TGR). Sera from 19 homeless people were reactive to TGR antigens by ELISA and IFA. Two people had antibodies against Rickettsia prowazekii (epidemic typhus) and the remaining 17 had antibodies agains...

  2. [Experimental study of the inoculative transmission of Rickettsia typhi by gamasid mites (Gamasidae) Ornithonyssus bacoti].

    PubMed

    Grabarev, P A; Suroviatkin, A V; Tikhonova, Iu Iu; Mishchenko, O A; Potapenko, O V

    2009-01-01

    The authors' studies have established that the concentration of Rickettsia typhi may increase about 100-fold in the infected Ornithonyssus bacoti mites. At the time, when on feeding 20 to 200 adult mites on guinea-pigs and albino rats 4 to 36 days after inoculation, they did not transmit Rickettsia typhi on blood sucking. PMID:19566066

  3. Rickettsia felis Infection in a Common Household Insect Pest, Liposcelis bostrychophila (Psocoptera: Liposcelidae)▿ †

    PubMed Central

    Behar, Adi; McCormick, Laurie J.; Perlman, Steve J.

    2010-01-01

    Many species of Rickettsia are well-known mammalian pathogens transmitted by blood-feeding arthropods. However, molecular surveys are continually uncovering novel Rickettsia species, often in unexpected hosts, including many arthropods that do not feed on blood. This study reports a systematic molecular characterization of a Rickettsia infecting the psocid Liposcelis bostrychophila (Psocoptera: Liposcelidae), a common and cosmopolitan household pest. Surprisingly, the psocid Rickettsia is shown to be Rickettsia felis, a human pathogen transmitted by fleas that causes serious morbidity and occasional mortality. The plasmid from the psocid R. felis was sequenced and was found to be virtually identical to the one in R. felis from fleas. As Liposcelis insects are often intimately associated with humans and other vertebrates, it is speculated that they acquired R. felis from fleas. Whether the R. felis in psocids causes disease in vertebrates is not known and warrants further study. PMID:20139311

  4. Identification of Rickettsia felis in the Salivary Glands of Cat Fleas

    PubMed Central

    Pornwiroon, Walairat; Popov, Vsevolod L.; Foil, Lane D.

    2008-01-01

    Abstract Rickettsia felis, a flea-associated rickettsial pathogen, has been identified in many tissues, including the digestive and reproductive tissues, within the cat flea, Ctenocephalides felis. We utilized transmission electron microscopy and polymerase chain reaction to identify R. felis in the salivary glands of fed fleas and further define the distribution of R. felis within the arthropod host. We identified Rickettsia-like organisms in salivary glands using electron microscopy. Sequence analysis of portions of the Rickettsia genus-specific 17-kDa antigen gene and R. felis plasmid confirmed the morphological identification of R. felis in cat flea salivary glands. This is the first report of R. felis in tissues critical for horizontal transmission of rickettsiae. Key Words: Cat flea—Ctenocephalides felis—Rickettsia felis. PMID:18399779

  5. Phylogenetic analysis of the rompB genes of Rickettsia felis and Rickettsia prowazekii European-human and North American flying-squirrel strains.

    PubMed

    Moron, C G; Bouyer, D H; Yu, X J; Foil, L D; Crocquet-Valdes, P; Walker, D H

    2000-05-01

    The rickettsial outer membrane protein B (rompB) gene encodes the major surface antigens of Rickettsia species. We undertook sequencing and molecular analysis of the rompB gene of Rickettsia felis and a comparison with its homologs in spotted fever group (SFG) and typhus group (TG) rickettsiae, including the complete sequences of two North American flying squirrel strains and two European human strains of Rickettsia prowazekii. We sequenced 5,226 base pairs (bp) of the R. felis rompB, encoding a protein of 1,654 amino acids. We also sequenced 5,015 bp of rompB of the flying squirrel strains, encoding a protein of 1,643 amino acids. Analysis of the R. felis rompB gene sequence showed 10-13% divergence from SFG rickettsiae and 18% divergence from the TG rickettsiae. The rompB of all sequenced strains of R. prowazekii showed an overall similarity of 99.7-99.9%. PMID:11289671

  6. Spotted fever group rickettsiae in ixodid ticks in Oromia, Ethiopia.

    PubMed

    Kumsa, Bersissa; Socolovschi, Cristina; Raoult, Didier; Parola, Philippe

    2015-02-01

    In Ethiopia, information on the transmission of human zoonotic pathogens through ixodid ticks remains scarce. To address the occurrence and molecular identity of spotted fever group rickettsiae using molecular tools, a total of 767 ixodid ticks belonging to thirteen different species were collected from domestic animals from September 2011 to March 2014. Rickettsia africae DNA was detected in 30.2% (16/53) Amblyommma variegatum, 28.6% (12/42) Am. gemma, 0.8% (1/119) Am. cohaerens, 18.2% (4/22) Amblyomma larvae, 6.7% (2/60) Amblyomma nymphs, 0.7% (1/139) Rhipicephalus (Boophilus) decoloratus and 25% (1/4) nymphs of Rh. (Bo.) decoloratus. A markedly low prevalence of R. africae was recorded in both Am. cohaerens and Rh. (Bo.) decoloratus (p<0.0001) compared with that in Am. variegatum and Am. gemma. The prevalence of R. africae was markedly low in the western districts (Gachi and Abdela) (p<0.0001); however, the prevalence of R. africae was relatively high in the central (Ada'a, Wolmara and Arsi) and eastern (Arero, Moyale and Yabelo) districts, where Am. variegatum and Am. gemma were predominantly associated with R. africae, respectively. R. aeschlimannii DNA was detected in 45.4% (5/11) Hyalomma marginatum rufipes and 2.2% (1/46) Hy. truncatum. Moreover, the first report of R. massiliae DNA in 1.9% (1/52) Rhipicephalus praetextatus ticks in Ethiopia is presented herein. Altogether, these results suggest that the transmission of spotted fever group rickettsiae through ixodid ticks is a potential risk for human health in different parts of Ethiopia. Clinicians in this country should consider these pathogens as a potential cause of febrile illness in patients. PMID:25262832

  7. Gene gain and loss events in Rickettsia and Orientia species

    PubMed Central

    2011-01-01

    Background Genome degradation is an ongoing process in all members of the Rickettsiales order, which makes these bacterial species an excellent model for studying reductive evolution through interspecies variation in genome size and gene content. In this study, we evaluated the degree to which gene loss shaped the content of some Rickettsiales genomes. We shed light on the role played by horizontal gene transfers in the genome evolution of Rickettsiales. Results Our phylogenomic tree, based on whole-genome content, presented a topology distinct from that of the whole core gene concatenated phylogenetic tree, suggesting that the gene repertoires involved have different evolutionary histories. Indeed, we present evidence for 3 possible horizontal gene transfer events from various organisms to Orientia and 6 to Rickettsia spp., while we also identified 3 possible horizontal gene transfer events from Rickettsia and Orientia to other bacteria. We found 17 putative genes in Rickettsia spp. that are probably the result of de novo gene creation; 2 of these genes appear to be functional. On the basis of these results, we were able to reconstruct the gene repertoires of "proto-Rickettsiales" and "proto-Rickettsiaceae", which correspond to the ancestors of Rickettsiales and Rickettsiaceae, respectively. Finally, we found that 2,135 genes were lost during the evolution of the Rickettsiaceae to an intracellular lifestyle. Conclusions Our phylogenetic analysis allowed us to track the gene gain and loss events occurring in bacterial genomes during their evolution from a free-living to an intracellular lifestyle. We have shown that the primary mechanism of evolution and specialization in strictly intracellular bacteria is gene loss. Despite the intracellular habitat, we found several horizontal gene transfers between Rickettsiales species and various prokaryotic, viral and eukaryotic species. Open peer review Reviewed by Arcady Mushegian, Eugene V. Koonin and Patrick Forterre. For

  8. Molecular detection of spotted fever group rickettsiae in Amblyomma variegatum ticks from Benin.

    PubMed

    Adjou Moumouni, Paul Franck; Terkawi, Mohamad Alaa; Jirapattharasate, Charoonluk; Cao, Shinuo; Liu, Mingming; Nakao, Ryo; Umemiya-Shirafuji, Rika; Yokoyama, Naoaki; Sugimoto, Chihiro; Fujisaki, Kozo; Suzuki, Hiroshi; Xuan, Xuenan

    2016-07-01

    Spotted fever group (SFG) rickettsiae are obligate intracellular, Gram-negative bacteria transmitted by ticks and causing febrile illness in humans. Despite the presence of suitable tick vectors, the occurrence of SFG rickettsiae has never been investigated in the Republic of Benin (West Africa). In the present study, 910 Amblyomma variegatum ticks collected from 8 different locations in North Eastern Benin were tested for SFG rickettsiae. The samples were first screened for the presence of rickettsial bacteria using 16S rDNA PCR and positive samples were subsequently characterized by ompA PCR. Randomly selected samples among those positive for both assays were subjected to sequencing of 16S rDNA and ompA genes for species identification. The 16S rDNA gene was amplified in 63.4% of the samples (585/910) and the SFG rickettsia-specific ompA gene was detected in 29.4% of the samples (267/910). The prevalence of SFG rickettsiae varied according to the location, and tick gender. Sequence analyses demonstrated the presence of Rickettsia africae and/or closely related species in Benin. These findings extend the geographic distribution of R. africae and spotted fever rickettsioses in Africa. Clinicians in Benin and those treating travellers should be aware of the possibility of SFG rickettsiae infection when they are treating patients with febrile illness. PMID:27150592

  9. Molecular detection of Rickettsia, Anaplasma, Coxiella and Francisella bacteria in ticks collected from Artiodactyla in Thailand.

    PubMed

    Sumrandee, Chalao; Baimai, Visut; Trinachartvanit, Wachareeporn; Ahantarig, Arunee

    2016-07-01

    A total of 79 ticks collected from Sambar deer (Cervus unicolor), Barking deer (Muntiacus muntjak) and Wild boar (Sus scrofa) were examined by PCR for the presence of Rickettsia, Anaplasma, Coxiella, and Francisella bacteria. Of the 79 ticks, 13% tested positive for Rickettsia, 15% tested positive for Anaplasma, 4% tested positive for Coxiella, and 3% tested positive for Francisella. Interestingly, triple infection with Anaplasma, Rickettsia and Francisella was determined in a Dermacentor auratus tick. Moreover, another triple infection with Rickettsia, Anaplasma, and Coxiella was found in a Haemaphysalis lagrangei tick. Double infection of Rickettsia with Coxiella was also detected in another H. lagrangei tick. From the phylogenetic analyses, we found a Rickettsia sp. with a close evolutionary relationship to Rickettsia bellii in the H. lagrangei tick. We also found the first evidence of a Rickettsia sp. that is closely related to Rickettsia tamurae in Rhipicephalus (Boophilus) microplus ticks from Thailand. H. lagrangei and Haemaphysalis obesa ticks collected from Sambar deer tested positive for Anaplasma species form the same clade with Anaplasma bovis. In contrast, other H. lagrangei ticks collected from Sambar deer and D. auratus ticks collected from Wild boar were also reported for the first time to be infected with an Anaplasma species that is closely related to Anaplasma platys. The phylogenetic analysis of the 16S rRNA gene of Coxiella bacteria revealed that Coxiella symbionts from H. lagrangei formed a distinctly different lineage from Coxiella burnetii (a human pathogen). Additionally, Francisella bacteria identified in D. auratus ticks were found to be distantly related to a group of pathogenic Francisella species. The identification of these bacteria in several feeding ticks suggests the risk of various emerging tick-borne diseases and endosymbionts in humans, wildlife, and domestic animals in Thailand. PMID:26934997

  10. Murine and epidemic typhus rickettsiae: how close is their relationship?

    PubMed

    Woodward, T E

    1982-01-01

    Typhus fever has occurred globally as epidemic and endemic disorders. In 1910, Brill reported a typhus-like illness which Zinsser and others determined to be recurrent epidemic typhus fever. Maxcy, in 1926, proposed rodents and fleas as reservoir and vector, respectively, of endemic typhus, which Dyer confirmed in 1930. Animals experimentally infected with epidemic typhus (Rickettsia prowazeki) are immune to murine typhus (Rickettsia typhi) and vice versa. Similar solid cross-immunity exists for humans. The two diseases are clinically similar in pathologic and serologic reactions. Human epidemic typhus presumably involved a man-louse-man cycle without an animal reservoir. This concept is now questioned. Antibodies to R. prowazeki have been reported in livestock in Africa, rats in Manila, and from flying squirrels and humans in the United States. R. prowazeki was recovered from blood specimens of goats, sheep, from ixodid ticks, louse, and flea-ectoparasites of flying squirrels, and tissues of flying squirrels. More than 20 cases of squirrel-related acute epidemic typhus have been reported in the United States. R. prowazeki has not been recovered from human cases. Chemical studies of R. prowazeki and R. typhi show genetic similarities but differences in genome size and degree of hybridization suggest that interconversions between the two agents do not occur rapidly in nature. It is proposed that, with time, their relatedness will become even closer. PMID:6817526

  11. Prostatitis, Steatitis, and Diarrhea in a Dog following Presumptive Flea-Borne Transmission of Bartonella henselae

    PubMed Central

    Balakrishnan, Nandhakumar; Pritchard, Jessica; Ericson, Marna; Grindem, Carol; Phillips, Kathryn; Jennings, Samuel; Mathews, Kyle; Tran, Huy; Birkenheuer, Adam J.

    2014-01-01

    Bartonella henselae is increasingly associated with a variety of pathological entities, which are often similar in dogs and human patients. Following an acute flea infestation, a dog developed an unusual clinical presentation for canine bartonellosis. Comprehensive medical, microbiological, and surgical interventions were required for diagnosis and to achieve a full recovery. PMID:24920774

  12. Classic flea-borne transmission does not drive plague epizootics in prairie dogs

    PubMed Central

    Webb, Colleen T.; Brooks, Christopher P.; Gage, Kenneth L.; Antolin, Michael F.

    2006-01-01

    We lack a clear understanding of the enzootic maintenance of the bacterium (Yersinia pestis) that causes plague and the sporadic epizootics that occur in its natural rodent hosts. A key to elucidating these epidemiological dynamics is determining the dominant transmission routes of plague. Plague can be acquired from the bites of infectious fleas (which is generally considered to occur via a blocked flea vector), inhalation of infectious respiratory droplets, or contact with a short-term infectious reservoir. We present results from a plague modeling approach that includes transmission from all three sources of infection simultaneously and uses sensitivity analysis to determine their relative importance. Our model is completely parameterized by using data from the literature and our own field studies of plague in the black-tailed prairie dog (Cynomys ludovicianus). Results of the model are qualitatively and quantitatively consistent with independent data from our field sites. Although infectious fleas might be an important source of infection and transmission via blocked fleas is a dominant paradigm in the literature, our model clearly predicts that this form of transmission cannot drive epizootics in prairie dogs. Rather, a short-term reservoir is required for epizootic dynamics. Several short-term reservoirs have the potential to affect the prairie dog system. Our model predictions of the residence time of the short-term reservoir suggest that other small mammals, infectious prairie dog carcasses, fleas that transmit plague without blockage of the digestive tract, or some combination of these three are the most likely of the candidate infectious reservoirs. PMID:16603630

  13. Comparative growth of spotted fever group Rickettsia spp. strains in Vero cells

    PubMed Central

    Silva, Arannadia Barbosa; Duarte, Myrian Morato; Vizzoni, Vinicius Figueiredo; Duré, Ana Íris de Lima; Lopéz, Diego Montenegro; Nogueira, Rita de Maria Seabra; Soares, Carlos Augusto Gomes; Machado-Ferreira, Erik; Gazêta, Gilberto Salles

    2016-01-01

    In Brazil, the spotted fever group (SFG) Rickettsia rickettsii and Rickettsia parkeri related species are the etiological agents of spotted fever rickettsiosis. However, the SFG, Rickettsia rhipicephali, that infects humans, has never been reported. The study of growth dynamics can be useful for understanding the infective and invasive capacity of these pathogens. Here, the growth rates of the Brazilian isolates R. rickettsii str. Taiaçu, R. parkeri str. At#24, and R. rhipicephali HJ#5, were evaluated in Vero cells by quantitative polymerase chain reaction. R. rhipicephali showed different kinetic growth compared to R. rickettsii and R. parkeri. PMID:27508322

  14. Comparative growth of spotted fever group Rickettsia spp. strains in Vero cells.

    PubMed

    Silva, Arannadia Barbosa; Duarte, Myrian Morato; Vizzoni, Vinicius Figueiredo; Duré, Ana Íris de Lima; Lopéz, Diego Montenegro; Nogueira, Rita de Maria Seabra; Soares, Carlos Augusto Gomes; Machado-Ferreira, Erik; Gazêta, Gilberto Salles

    2016-08-01

    In Brazil, the spotted fever group (SFG) Rickettsia rickettsii and Rickettsia parkeri related species are the etiological agents of spotted fever rickettsiosis. However, the SFG, Rickettsia rhipicephali, that infects humans, has never been reported. The study of growth dynamics can be useful for understanding the infective and invasive capacity of these pathogens. Here, the growth rates of the Brazilian isolates R. rickettsii str. Taiaçu, R. parkeri str. At#24, and R. rhipicephali HJ#5, were evaluated in Vero cells by quantitative polymerase chain reaction. R. rhipicephali showed different kinetic growth compared to R. rickettsii and R. parkeri. PMID:27508322

  15. Molecular detection and groEL typing of Rickettsia aeschlimannii in Sardinian ticks.

    PubMed

    Chisu, Valentina; Zobba, Rosanna; Foxi, Cipriano; Pisu, Danilo; Masala, Giovanna; Alberti, Alberto

    2016-09-01

    Rickettsia aeschlimannii is an emerging tick-borne pathogen of the spotted fever group Rickettsiae with considerable impact on both human and animal health. This study reports the molecular detection and groEL characterization of R. aeschlimannii in ticks collected from birds and ruminants in a typical Mediterranean environment. Phylogeny of R. aeschlimannii and species representative of the spotted fever and typhus groups based on the groEL gene is reconstructed for the first time. Results expand the knowledge on distribution and typing of emerging human tick-borne diseases in Sardinia and pave the way for future molecular epidemiology studies of zoonotic Rickettsiae. PMID:27130322

  16. Sequencing and comparison of the Rickettsia genomes from the whitefly Bemisia tabaci Middle East Asia Minor I.

    PubMed

    Zhu, Dan-Tong; Xia, Wen-Qiang; Rao, Qiong; Liu, Shu-Sheng; Ghanim, Murad; Wang, Xiao-Wei

    2016-08-01

    The whitefly, Bemisia tabaci, harbors the primary symbiont 'Candidatus Portiera aleyrodidarum' and a variety of secondary symbionts. Among these secondary symbionts, Rickettsia is the only one that can be detected both inside and outside the bacteriomes. Infection with Rickettsia has been reported to influence several aspects of the whitefly biology, such as fitness, sex ratio, virus transmission and resistance to pesticides. However, mechanisms underlying these differences remain unclear, largely due to the lack of genomic information of Rickettsia. In this study, we sequenced the genome of two Rickettsia strains isolated from the Middle East Asia Minor 1 (MEAM1) species of the B. tabaci complex in China and Israel. Both Rickettsia genomes were of high coding density and AT-rich, containing more than 1000 coding sequences, much larger than that of the coexisted primary symbiont, Portiera. Moreover, the two Rickettsia strains isolated from China and Israel shared most of the genes with 100% identity and only nine genes showed sequence differences. The phylogenetic analysis using orthologs shared in the genus, inferred the proximity of Rickettsia in MEAM1 and Rickettsia bellii. Functional analysis revealed that Rickettsia was unable to synthesize amino acids required for complementing the whitefly nutrition. Besides, a type IV secretion system and a number of virulence-related genes were detected in the Rickettsia genome. The presence of virulence-related genes might benefit the symbiotic life of the bacteria, and hint on potential effects of Rickettsia on whiteflies. The genome sequences of Rickettsia provided a basis for further understanding the function of Rickettsia in whiteflies. PMID:27273750

  17. Detection of Rickettsia parkeri from within Piura, Peru, and the First Reported Presence of Candidatus Rickettsia andeanae in the Tick Rhipicephalus sanguineus

    PubMed Central

    Flores-Mendoza, Carmen; Florin, David; Felices, Vidal; Pozo, Edwar J.; Graf, Paul C.F.; Richards, Allen L.

    2013-01-01

    Abstract Domestic farm animals (n=145) were sampled for the presence of ectoparasites in northwestern Peru during March, 2008. Ninety domestic animals (62%) were positive for the presence of an ectoparasite(s) and produced a total collection of the following: 728 ticks [Amblyomma maculatum, Anocentor nitens, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus, and Otobius megnini], 12 lice (Haematopinus suis), and 3 fleas (Ctenocephalides felis). A Rickettsia genus-specific qPCR assay was performed on nucleic acid preparations of the collected ectoparasites that resulted in 5% (37/743, 35 ticks and 2 fleas) of the ectoparasites positive for the presence of Rickettsia. DNA from the positive individual ticks was tested with 2 other qPCR assays for the presence of the ompB gene in Candidatus Rickettsia andeanae or Rickettsia parkeri. Candidatus R. andeanae was found in 25 A. maculatum ticks and in two Rh. sanguineus ticks, whereas R. parkeri was detected in 6 A. maculatum ticks. Two A. maculatum were co-infected with both Candidatus R. andeanae and R. parkeri. Rickettsia felis was detected in 2 fleas, Ctenocephalides felis, by multilocus sequence typing of the 17-kD antigen and ompA genes. These findings expand the geographic range of R. parkeri to include Peru as well as expand the natural arthropod vector of Candidatus R. andeanae to include Rhipicephalus sanguineus. PMID:23488453

  18. Detection of Rickettsia parkeri from within Piura, Peru, and the first reported presence of Candidatus Rickettsia andeanae in the tick Rhipicephalus sanguineus.

    PubMed

    Flores-Mendoza, Carmen; Florin, David; Felices, Vidal; Pozo, Edwar J; Graf, Paul C F; Burrus, Roxanne G; Richards, Allen L

    2013-07-01

    Domestic farm animals (n=145) were sampled for the presence of ectoparasites in northwestern Peru during March, 2008. Ninety domestic animals (62%) were positive for the presence of an ectoparasite(s) and produced a total collection of the following: 728 ticks [Amblyomma maculatum, Anocentor nitens, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus, and Otobius megnini], 12 lice (Haematopinus suis), and 3 fleas (Ctenocephalides felis). A Rickettsia genus-specific qPCR assay was performed on nucleic acid preparations of the collected ectoparasites that resulted in 5% (37/743, 35 ticks and 2 fleas) of the ectoparasites positive for the presence of Rickettsia. DNA from the positive individual ticks was tested with 2 other qPCR assays for the presence of the ompB gene in Candidatus Rickettsia andeanae or Rickettsia parkeri. Candidatus R. andeanae was found in 25 A. maculatum ticks and in two Rh. sanguineus ticks, whereas R. parkeri was detected in 6 A. maculatum ticks. Two A. maculatum were co-infected with both Candidatus R. andeanae and R. parkeri. Rickettsia felis was detected in 2 fleas, Ctenocephalides felis, by multilocus sequence typing of the 17-kD antigen and ompA genes. These findings expand the geographic range of R. parkeri to include Peru as well as expand the natural arthropod vector of Candidatus R. andeanae to include Rhipicephalus sanguineus. PMID:23488453

  19. Evidence of Rickettsia and Orientia Infections Among Abattoir Workers in Djibouti.

    PubMed

    Horton, Katherine C; Jiang, Ju; Maina, Alice; Dueger, Erica; Zayed, Alia; Ahmed, Ammar Abdo; Pimentel, Guillermo; Richards, Allen L

    2016-08-01

    Of 49 workers at a Djiboutian abattoir, eight (16%, 95% confidence interval [CI]: 9-29) were seropositive against spotted fever group rickettsiae (SFGR), two (4%, 95% CI: 1-14) against typhus group rickettsiae, and three (6%, 95% CI: 2-17) against orientiae. One worker (9%, 95% CI: 2-38) seroconverted against orientiae during the study period. This is the first evidence of orientiae exposure in the Horn of Africa. SFGR were also identified by polymerase chain reaction in 32 of 189 (11%, 95% CI: 8-15) tick pools from 26 of 72 (36%) cattle. Twenty-five (8%, 95% CI: 6-12) tick pools were positive for Rickettsia africae, the causative agent of African tick-bite fever. Health-care providers in Djibouti should be aware of the possibility of rickettsiae infections among patients, although further research is needed to determine the impact of these infections in the country. PMID:27273647

  20. A Focus of Dogs and Rickettsia massiliae–Infected Rhipicephalus sanguineus in California

    PubMed Central

    Beeler, Emily; Abramowicz, Kyle F.; Zambrano, Maria L.; Sturgeon, Michele M.; Khalaf, Nada; Hu, Renjie; Dasch, Gregory A.; Eremeeva, Marina E.

    2011-01-01

    A recurrent focus of Rhipicephalus sanguineus infestation was investigated in a suburban area of southern California after reports of suspected Rocky Mountain spotted fever in two dogs on the same property. Abundant quantities of Rh. sanguineus were collected on the property and repeatedly from each dog, and Rickettsia massiliae DNA was detected by polymerase chain reaction (PCR). Whole blood and serum samples from four dogs were tested by using PCR and microimmunofluorescent assay for antibodies against spotted fever group rickettsiae. Serum samples from all four dogs contained antibodies reactive with R. massiliae, R. rhipicephali, R. rickettsii, and 364D Rickettsia but no rickettsial DNA was detected by PCR of blood samples. Serum cross-absorption and Western blot assays implicated R. massiliae as the most likely spotted fever group rickettsiae responsible for seropositivity. To our knowledge, this is the first detection of R. massiliae in ticks in California. PMID:21292893

  1. Spotted fever group rickettsiae in ticks collected from wild animals in Israel.

    PubMed

    Keysary, Avi; Eremeeva, Marina E; Leitner, Moshe; Din, Adi Beth; Wikswo, Mary E; Mumcuoglu, Kosta Y; Inbar, Moshe; Wallach, Arian D; Shanas, Uri; King, Roni; Waner, Trevor

    2011-11-01

    We report molecular evidence for the presence of spotted fever group rickettsiae (SFGR) in ticks collected from roe deer, addax, red foxes, and wild boars in Israel. Rickettsia aeschlimannii was detected in Hyalomma marginatum and Hyalomma detritum while Rickettsia massiliae was present in Rhipicephalus turanicus ticks. Furthermore, a novel uncultured SFGR was detected in Haemaphysalis adleri and Haemaphysalis parva ticks from golden jackals. The pathogenicity of the novel SFGR for humans is unknown; however, the presence of multiple SFGR agents should be considered when serological surveillance data from Israel are interpreted because of significant antigenic cross-reactivity among Rickettsia. The epidemiology and ecology of SFGR in Israel appear to be more complicated than was previously believed. PMID:22049050

  2. Phospholipase A and the interaction of Rickettsia prowazekii and mouse fibroblasts (L-929 cells)

    SciTech Connect

    Winkler, H.H.; Miller, E.T.

    1982-10-01

    L-929 cells were killed when approximately 50 viable Rickettsia prowazekii organisms per L-cell were centrifuged onto a monolayer. The glycerophospholipids of the L-cell were hydrolyzed to lysophosphatides and free fatty acids. Concomitantly, there was a loss of membrane integrity as shown by release of lactate dehydrogenase and 86Rb and permeability to trypan blue dye. No glycerophospholipid hydrolysis or cytotoxicity occurred when the rickettsiae were inactivated by heat, UV irradiation, N-ethylmaleimide, or metabolic inhibitors before their addition to the L-929 cells. On the other hand, treatment of the L929 cells with the cytoskeleton agents colchicine or cytochalasin B or with N-ethylmaleimide inhibited neither the phospholipase A activity nor the loss of membrane integrity. Cytochalasin B-treated cells could be damaged by even small numbers of rickettsiae. We suggest that this phospholipase A activity is used by the rickettsiae to escape from the phagosomes into the cytoplasm of host cells.

  3. Spotted Fever Group Rickettsiae in Ticks Collected from Wild Animals in Israel

    PubMed Central

    Keysary, Avi; Eremeeva, Marina E.; Leitner, Moshe; Din, Adi Beth; Wikswo, Mary E.; Mumcuoglu, Kosta Y.; Inbar, Moshe; Wallach, Arian D.; Shanas, Uri; King, Roni; Waner, Trevor

    2011-01-01

    We report molecular evidence for the presence of spotted fever group rickettsiae (SFGR) in ticks collected from roe deer, addax, red foxes, and wild boars in Israel. Rickettsia aeschlimannii was detected in Hyalomma marginatum and Hyalomma detritum while Rickettsia massiliae was present in Rhipicephalus turanicus ticks. Furthermore, a novel uncultured SFGR was detected in Haemaphysalis adleri and Haemaphysalis parva ticks from golden jackals. The pathogenicity of the novel SFGR for humans is unknown; however, the presence of multiple SFGR agents should be considered when serological surveillance data from Israel are interpreted because of significant antigenic cross-reactivity among Rickettsia. The epidemiology and ecology of SFGR in Israel appear to be more complicated than was previously believed. PMID:22049050

  4. Prevalence of antibodies to spotted fever group rickettsiae along the eastern coast of the Adriatic sea.

    PubMed Central

    Radulovic, S; Walker, D H; Weiss, K; Dzelalija, B; Morovic, M

    1993-01-01

    A seroepidemiological survey in coastal Croatia detected antibodies reactive with Rickettsia conorii in 4.2% of sera by immunofluorescence assay and in 5.0% of sera by enzyme immunoassay. Western immunoblotting demonstrated antibodies to the 120-kDa surface protein in all 20 positive serum samples examined and to rickettsial lipopolysaccharide in 3 of these serum samples. Humans in this area are clearly being exposed to spotted fever rickettsiae. PMID:8370756

  5. Infection of Amblyomma ovale by Rickettsia sp. strain Atlantic rainforest, Colombia.

    PubMed

    Londoño, Andrés F; Díaz, Francisco J; Valbuena, Gustavo; Gazi, Michal; Labruna, Marcelo B; Hidalgo, Marylin; Mattar, Salim; Contreras, Verónica; Rodas, Juan D

    2014-10-01

    Our goal was to understand rickettsial spotted fevers' circulation in areas of previous outbreaks reported from 2006 to 2008 in Colombia. We herein present molecular identification and isolation of Rickettsia sp. Atlantic rainforest strain from Amblyomma ovale ticks, a strain shown to be pathogenic to humans. Infected ticks were found on dogs and a rodent in Antioquia and Córdoba Provinces. This is the first report of this rickettsia outside Brazil, which expands its known range considerably. PMID:25090976

  6. Rickettsia retinitis cases in India: a few comments.

    PubMed

    Tripathy, Koushik; Chawla, Rohan; Sharma, Yog Raj; Vohra, Rajpal

    2016-12-01

    An important cause of infectious retinitis, not well-described in Indian literature, has been analyzed in detail systematically by Kawali A. and colleagues. However, Rickettsia retinitis (RR) was diagnosed at titres of 1:160 by the Weil-Felix test (WFT). The sensitivity and specificity of WFT at this level are poor compared to the gold standard immunofluorescent antibody assay. However, we understand that financial constraints of the Indian patients limit the availability of more definite tests. In our opinion, the optical coherence tomography features of RR described by the authors may be mimicked by other causes of retinitis, such as toxoplasma retinitis or even cotton wool spots. Infectious retinitis including RR should be treated by an antimicrobial agent with or without oral steroids until larger series or randomized controlled trials prove otherwise. PMID:26920002

  7. ESCCAR international congress on Rickettsia and other intracellular bacteria.

    PubMed

    de Barsy, Marie; Bertelli, Claire; Jacquier, Nicolas; Kebbi-Beghdadi, Carole; Greub, Gilbert

    2015-10-01

    The European Society for the study of Chlamydia, Coxiella, Anaplasma and Rickettsia (ESCCAR) held his triennial international meeting in Lausanne. This meeting gathered 165 scientists from 28 countries and all 5 continents, allowing efficient networking and major scientific exchanges. Topics covered include molecular and cellular microbiology, genomics, as well as epidemiology, veterinary and human medicine. Several breakthroughs have been revealed at the meeting, such as (i) the presence of CRISPR (the "prokaryotic immune system") in chlamydiae, (ii) an Anaplasma effector involved in host chromatin remodelling, (iii) the polarity of the type III secretion system of chlamydiae during the entry process revealed by cryo-electron tomography. Moreover, the ESCCAR meeting was a unique opportunity to be exposed to cutting-edge science and to listen to comprehensive talks on current hot topics. PMID:26297854

  8. Experimental Infection of Amblyomma aureolatum Ticks with Rickettsia rickettsii

    PubMed Central

    Ogrzewalska, Maria; Soares, João F.; Martins, Thiago F.; Soares, Herbert S.; Moraes-Filho, Jonas; Nieri-Bastos, Fernanda A.; Almeida, Aliny P.; Pinter, Adriano

    2011-01-01

    We experimentally infected Amblyomma aureolatum ticks with the bacterium Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever (RMSF). These ticks are a vector for RMSF in Brazil. R. rickettsii was efficiently conserved by both transstadial maintenance and vertical (transovarial) transmission to 100% of the ticks through 4 laboratory generations. However, lower reproductive performance and survival of infected females was attributed to R. rickettsii infection. Therefore, because of the high susceptibility of A. aureolatum ticks to R. rickettsii infection, the deleterious effect that the bacterium causes in these ticks may contribute to the low infection rates (<1%) usually reported among field populations of A. aureolatum ticks in RMSF-endemic areas of Brazil. Because the number of infected ticks would gradually decrease after each generation, it seems unlikely that A. aureolatum ticks could sustain R. rickettsii infection over multiple successive generations solely by vertical transmission. PMID:21529391

  9. Rickettsia Detected in the Reptile Tick Bothriocroton hydrosauri from the Lizard Tiliqua rugosa in South Australia.

    PubMed

    Whiley, Harriet; Custance, Georgie; Graves, Stephen; Stenos, John; Taylor, Michael; Ross, Kirstin; Gardner, Michael G

    2016-01-01

    Rickettsiosis is a potentially fatal tick borne disease. It is caused by the obligate intracellular bacteria Rickettsia, which is transferred to humans through salivary excretions of ticks during the biting process. Globally, the incidence of tick-borne diseases is increasing; as such, there is a need for a greater understanding of tick-host interactions to create more informed risk management strategies. Flinders Island spotted fever rickettsioses has been identified throughout Australia (Tasmania, South Australia, Queensland and Torres Strait Islands) with possible identifications in Thailand, Sri Lanka and Italy. Flinders Island spotted fever is thought to be spread through tick bites and the reptile tick Bothriocroton hydrosauri has been implicated as a vector in this transmission. This study used qPCR to assay Bothriocroton hydrosauri ticks collected from Tiliqua rugosa (sleepy lizard) hosts on mainland South Australia near where spotted fever cases have been identified. We report that, although we discovered Rickettsia in all tick samples, it was not Rickettsia honei. This study is the first to use PCR to positively identify Rickettsia from South Australian Bothriocroton hydrosauri ticks collected from Tiliqua rugosa (sleepy lizard) hosts. These findings suggest that B. hydrosauri may be a vector of multiple Rickettsia spp. Also as all 41 tested B. hydrosauri ticks were positive for Rickettsia this indicates an extremely high prevalence within the studied area in South Australia. PMID:27338482

  10. Molecular evidence of spotted fever group rickettsiae and Anaplasmataceae from ticks and stray dogs in Bangladesh.

    PubMed

    Qiu, Yongjin; Nakao, Ryo; Thu, May June; Akter, Shirin; Alam, Mohammad Zahangir; Kato, Satomi; Katakura, Ken; Sugimoto, Chihiro

    2016-03-01

    Emerging tick-borne diseases (TBDs) are important foci for human and animal health worldwide. However, these diseases are sometimes over looked, especially in countries with limited resources to perform molecular-based surveys. The aim of this study was to detect and characterize spotted fever group (SFG) rickettsiae and Anaplasmataceae in Bangladesh, which are important tick-borne pathogens for humans and animals worldwide. A total of 50 canine blood samples, 15 ticks collected from dogs, and 154 ticks collected from cattle were screened for the presence of SFG rickettsiae and Anaplasmataceae using molecular-based methods such as PCR and real-time PCR. The sequence analysis of the amplified products detected two different genotypes of SFG rickettsiae in ticks from cattle. The genotype detected in Rhipicephalus microplus was closely related to Rickettsia monacensis, while the genotype detected in Haemaphysalis bispinosa was closely related to Rickettsia sp. found in Korea and Japan. Anaplasma bovis was detected in canine blood and ticks (Rhipicephalus sanguineus and H. bispinosa). Unexpectedly, the partial genome sequence of Wolbachia sp., presumably associated with the nematode Dirofilaria immitis, was identified in canine blood. The present study provides the first molecular evidence of SFG rickettsiae and A. bovis in Bangladesh, indicating the possible emergence of previously unrecognized TBDs in this country. PMID:26573516

  11. Rickettsia Detected in the Reptile Tick Bothriocroton hydrosauri from the Lizard Tiliqua rugosa in South Australia

    PubMed Central

    Whiley, Harriet; Custance, Georgie; Graves, Stephen; Stenos, John; Taylor, Michael; Ross, Kirstin; Gardner, Michael G.

    2016-01-01

    Rickettsiosis is a potentially fatal tick borne disease. It is caused by the obligate intracellular bacteria Rickettsia, which is transferred to humans through salivary excretions of ticks during the biting process. Globally, the incidence of tick-borne diseases is increasing; as such, there is a need for a greater understanding of tick–host interactions to create more informed risk management strategies. Flinders Island spotted fever rickettsioses has been identified throughout Australia (Tasmania, South Australia, Queensland and Torres Strait Islands) with possible identifications in Thailand, Sri Lanka and Italy. Flinders Island spotted fever is thought to be spread through tick bites and the reptile tick Bothriocroton hydrosauri has been implicated as a vector in this transmission. This study used qPCR to assay Bothriocroton hydrosauri ticks collected from Tiliqua rugosa (sleepy lizard) hosts on mainland South Australia near where spotted fever cases have been identified. We report that, although we discovered Rickettsia in all tick samples, it was not Rickettsia honei. This study is the first to use PCR to positively identify Rickettsia from South Australian Bothriocroton hydrosauri ticks collected from Tiliqua rugosa (sleepy lizard) hosts. These findings suggest that B. hydrosauri may be a vector of multiple Rickettsia spp. Also as all 41 tested B. hydrosauri ticks were positive for Rickettsia this indicates an extremely high prevalence within the studied area in South Australia. PMID:27338482

  12. Detection of a novel spotted fever group Rickettsia in the gophertortoise tick.

    PubMed

    Zemtsova, Galina E; Gleim, Elizabeth; Yabsley, Michael J; Conner, L Mike; Mann, Tom; Brown, Mary D; Wendland, Lori; Levin, Michael L

    2012-05-01

    The gophertortoise tick, Amblyomma tuberculatum (Marx), is distributed throughout the southeastern United States, and its immature life stages have been reported to occasionally bite humans. Here we report detection of a novel spotted fever group (SFG) Rickettsia in A. tuberculatum ticks collected in the southern United States. Among questing ticks collected in Georgia, 10 pools of larvae were identified as gophertortoise ticks, A. tuberculatum. Each of these samples was positive for SFG Rickettsiae. The restriction fragment-length polymorphism profiles were identical to each other, but distinct from those of other rickettsiae previously found in Amblyomma spp. ticks. Partial genetic characterization of the novel agent was achieved by sequencing the 17 kDa, gltA, ompB, ompA, rpoB, and sca4 genes. Analysis of a concatenated tree of four genes (gltA, ompB, ompA, and sca4) demonstrates close relatedness of the detected Rickettsia to several SFG Rickettsia spp. The identical rickettsial DNA was detected in 50 and 70% of adult A. tuberculatum ticks from Mississippi and Florida, respectively. The results indicate wide distribution of a novel Rickettsia, capability for transovarial transmission, and high prevalence in tested tick populations. PMID:22679890

  13. Conditional fitness benefits of the Rickettsia bacterial symbiont in an insect pest.

    PubMed

    Cass, Bodil N; Himler, Anna G; Bondy, Elizabeth C; Bergen, Jacquelyn E; Fung, Sierra K; Kelly, Suzanne E; Hunter, Martha S

    2016-01-01

    Inherited bacterial symbionts are common in arthropods and can have strong effects on the biology of their hosts. These effects are often mediated by host ecology. The Rickettsia symbiont can provide strong fitness benefits to its insect host, Bemisia tabaci, under laboratory and field conditions. However, the frequency of the symbiont is heterogeneous among field collection sites across the USA, suggesting that the benefits of the symbiont are contingent on additional factors. In two whitefly genetic lines collected from the same location, we tested the effect of Rickettsia on whitefly survival after heat shock, on whitefly competitiveness at different temperatures, and on whitefly competitiveness at different starting frequencies of Rickettsia. Rickettsia did not provide protection against heat shock nor affect the competitiveness of whiteflies at different temperatures or starting frequencies. However, there was a strong interaction between Rickettsia infection and whitefly genetic line. Performance measures indicated that Rickettsia was associated with significant female bias in both whitefly genetic lines, but in the second whitefly genetic line it conferred no significant fitness benefits nor conferred any competitive advantage to its host over uninfected whiteflies in population cages. These results help to explain other reports of variation in the phenotype of the symbiosis. Furthermore, they demonstrate the complex nature of these close symbiotic associations and the need to consider these interactions in the context of host population structure. PMID:26376661

  14. Identification and Characterization of Novel Small RNAs in Rickettsia prowazekii

    PubMed Central

    Schroeder, Casey L. C.; Narra, Hema P.; Sahni, Abha; Rojas, Mark; Khanipov, Kamil; Patel, Jignesh; Shah, Riya; Fofanov, Yuriy; Sahni, Sanjeev K.

    2016-01-01

    Emerging evidence implicates a critically important role for bacterial small RNAs (sRNAs) as post-transcriptional regulators of physiology, metabolism, stress/adaptive responses, and virulence, but the roles of sRNAs in pathogenic Rickettsia species remain poorly understood. Here, we report on the identification of both novel and well-known bacterial sRNAs in Rickettsia prowazekii, known to cause epidemic typhus in humans. RNA sequencing of human microvascular endothelial cells (HMECs), the preferred targets during human rickettsioses, infected with R. prowazekii revealed the presence of 35 trans-acting and 23 cis-acting sRNAs, respectively. Of these, expression of two trans-acting (Rp_sR17 and Rp_sR60) and one cis-acting (Rp_sR47) novel sRNAs and four well-characterized bacterial sRNAs (RNaseP_bact_a, α-tmRNA, 4.5S RNA, 6S RNA) was further confirmed by Northern blot or RT-PCR analyses. The transcriptional start sites of five novel rickettsial sRNAs and 6S RNA were next determined using 5′ RLM-RACE yielding evidence for their independent biogenesis in R. prowazekii. Finally, computational approaches were employed to determine the secondary structures and potential mRNA targets of novel sRNAs. Together, these results establish the presence and expression of sRNAs in R. prowazekii during host cell infection and suggest potential functional roles for these important post-transcriptional regulators in rickettsial biology and pathogenesis. PMID:27375581

  15. Multimethylation of Rickettsia OmpB Catalyzed by Lysine Methyltransferases*

    PubMed Central

    Abeykoon, Amila; Wang, Guanghui; Chao, Chien-Chung; Chock, P. Boon; Gucek, Marjan; Ching, Wei-Mei; Yang, David C. H.

    2014-01-01

    Methylation of rickettsial OmpB (outer membrane protein B) has been implicated in bacterial virulence. Rickettsial methyltransferases RP789 and RP027-028 are the first biochemically characterized methyltransferases to catalyze methylation of outer membrane protein (OMP). Methylation in OMP remains poorly understood. Using semiquantitative integrated liquid chromatography-tandem mass spectroscopy, we characterize methylation of (i) recombinantly expressed fragments of Rickettsia typhi OmpB exposed in vitro to trimethyltransferases of Rickettsia prowazekii RP027-028 and of R. typhi RT0101 and to monomethyltransferases of R. prowazekii RP789 and of R. typhi RT0776, and (ii) native OmpBs purified from R. typhi and R. prowazekii strains Breinl, RP22, and Madrid E. We found that in vitro trimethylation occurs at relatively specific locations in OmpB with consensus motifs, KX(G/A/V/I)N and KT(I/L/F), whereas monomethylation is pervasive throughout OmpB. Native OmpB from virulent R. typhi contains mono- and trimethyllysines at locations well correlated with methylation in recombinant OmpB catalyzed by methyltransferases in vitro. Native OmpBs from highly virulent R. prowazekii strains Breinl and RP22 contain multiple clusters of trimethyllysine in contrast to a single cluster in OmpB from mildly virulent R. typhi. Furthermore, OmpB from the avirulent strain Madrid E contains mostly monomethyllysine and no trimethyllysine. The native OmpB from Madrid E was minimally trimethylated by RT0101 or RP027-028, consistent with a processive mechanism of trimethylation. This study provides the first in-depth characterization of methylation of an OMP at the molecular level and may lead to uncovering the link between OmpB methylation and rickettsial virulence. PMID:24497633

  16. High prevalence of "Candidatus Rickettsia amblyommii" in Amblyomma ticks from a Spotted Fever Endemic Region in North Argentina.

    PubMed

    Mastropaolo, Mariano; Tarragona, Evelina L; Silaghi, Cornelia; Pfister, Kurt; Thiel, Claudia; Nava, Santiago

    2016-06-01

    Ticks from an endemic Spotted Fever region in Argentina were analysed by PCR for Spotted Fever Group Rickettsiae. DNA of "Candidatus Rickettsia amblyommii" was found in 21.3% of Amblyomma hadanii and in 44.0% of A. neumanni. Amblyomma sculptum (formerly A. cajennense) and Haemaphysalis juxtakochi were negative for rickettsial DNA. DNA of Rickettsia rickettsii, the etiological agent of the clinical cases reported within the studied region was not detected in the analysed sample. PMID:27260814

  17. Changes in immunoferritin labeling of Rickettsia tsutsugamushi after serial cultivation in 60Co-irradiated BHK cells.

    PubMed Central

    Rikihisa, Y; Rota, T; Lee, T H; MacDonald, A B; Ito, S

    1979-01-01

    The immunolabeling characteristics of Rickettsia tsutsugamushi (Gilliam strain) were examined by using a purified immunoglobulin G fraction of antibody to R. tsutsugamushi raised in rabbits. Formalin-fixed rickettsiae were reacted with this antibody and then with ferritin-conjugated goat anti-rabbit Fc antibody. R. tsutsugamushi cultivated in yolk sacs was used to raise antibody for this study. When rickettsiae in BHK-21 cells infected from yolk sac seed material were immunoferritin labeled, the binding of ferritin was found to be dense and uniform on the outer surface of the rickettsiae in disrupted host cells. Immunolabeling of purified suspensions of extracellular rickettsiae resulted in the uniform ferritin labeling of the microorganism. Aggregation of these rickettsiae by antibody appeared to depend upon the purity of the pellets. Immunoferritin labeling examined at high magnification revealed ferritin very close to the outer dense leaflet of the outer membrane. On some rickettsiae or on focal sites of others, the labelin; was several ferritin particles thick, suggesting the presence of a thick coating. The immunoferritin labeling of R. tsutsugamushi during successive serial passages in BHK-21 cells revealed decreased labeling with each passage, and by the 10th passage there was no detectable labeling. However, these rickettsiae inoculated back into yolk sacs regained their immunoferritin labeling. R. tsutsugamushi passed back into yolk sacs after four serial propagations in BHK-21 cells regained their labeling on the first passage in yolk sacs. However, rickettsiae from the 20th serial passage in BHK-21 cells required five passages in yolk sacs to reestablish their previous labeling affinity. Rickettsiae which did not label after 20 passages in BHK cells regained some of their labeling characteristics when sonicated. Antibody against rickettsiae cultivated in BHK-21 cells continued labeling rickettsiae even after 9 serial passages in BHK-21 cells. Images PMID

  18. Exposure of dogs to spotted fever group rickettsiae in urban sites associated with human rickettsioses in Costa Rica.

    PubMed

    Moreira-Soto, Andrés; Carranza, Marco V; Taylor, Lizeth; Calderón-Arguedas, Olger; Hun, Laya; Troyo, Adriana

    2016-07-01

    The zoonotic transmission cycles of Rickettsia rickettsii and other spotted fever group (SFG) rickettsiae in Latin America have usually been associated with rural or sylvatic environments, although domestic dogs can be implicated in more populated settings. In this study, exposure of dogs to SFG rickettsiae in the Greater Metropolitan Area of Costa Rica was investigated. Dogs from sites associated with human cases and from dog shelters were evaluated by indirect immunofluorescence assay (IFA) using antigen of SFG rickettsiae. Rickettsia spp. were detected in ectoparasites by polymerase chain reaction (PCR). A total 18.5% (31/168) of dogs associated with human cases and 6.8% (11/161) of dogs in shelters had IgG end titers≥64 to Rickettsia spp. The odds of being seropositive were greater in dogs from areas associated with human cases when compared to shelters (OR: 3.2; 95% C.I: 1.5-5.6). Rhipicephalus sanguineus sensu lato (s. l.) was present in all sites associated with human cases. Rickettsia felis URRWXCal2 and R. felis-like RF2125 were detected in Ctenocephalides felis, and Rickettsia sp. IbR/CRC in Ixodes boliviensis. Results demonstrate that dogs from the main urban center of Costa Rica have been exposed to SFG rickettsiae, especially in areas with known human infection. Both human and animal health sectors must be aware of possible rickettsial diseases in urban areas, where dogs may also serve as sentinels for human infection. PMID:26995323

  19. Detection of Rickettsia and Ehrlichia spp. in Ticks Associated with Exotic Reptiles and Amphibians Imported into Japan.

    PubMed

    Andoh, Masako; Sakata, Akiko; Takano, Ai; Kawabata, Hiroki; Fujita, Hiromi; Une, Yumi; Goka, Koichi; Kishimoto, Toshio; Ando, Shuji

    2015-01-01

    One of the major routes of transmission of rickettsial and ehrlichial diseases is via ticks that infest numerous host species, including humans. Besides mammals, reptiles and amphibians also carry ticks that may harbor Rickettsia and Ehrlichia strains that are pathogenic to humans. Furthermore, reptiles and amphibians are exempt from quarantine in Japan, thus facilitating the entry of parasites and pathogens to the country through import. Accordingly, in the current study, we examined the presence of Rickettsia and Ehrlichia spp. genes in ticks associated with reptiles and amphibians originating from outside Japan. Ninety-three ticks representing nine tick species (genera Amblyomma and Hyalomma) were isolated from at least 28 animals spanning 10 species and originating from 12 countries (Ghana, Jordan, Madagascar, Panama, Russia, Sri Lanka, Sudan, Suriname, Tanzania, Togo, Uzbekistan, and Zambia). None of the nine tick species are indigenous in Japan. The genes encoding the common rickettsial 17-kDa antigen, citrate synthase (gltA), and outer membrane protein A (ompA) were positively detected in 45.2% (42/93), 40.9% (38/93), and 23.7% (22/93) of the ticks, respectively, by polymerase chain reaction (PCR). The genes encoding ehrlichial heat shock protein (groEL) and major outer membrane protein (omp-1) were PCR-positive in 7.5% (7/93) and 2.2% (2/93) of the ticks, respectively. The p44 gene, which encodes the Anaplasma outer membrane protein, was not detected. Phylogenetic analysis showed that several of the rickettsial and ehrlichial sequences isolated in this study were highly similar to human pathogen genes, including agents not previously detected in Japan. These data demonstrate the global transportation of pathogenic Rickettsia and Ehrlichia through reptile- and amphibian-associated ticks. These imported animals have potential to transfer pathogens into human life. These results highlight the need to control the international transportation of known and

  20. Detection of Rickettsia and Ehrlichia spp. in Ticks Associated with Exotic Reptiles and Amphibians Imported into Japan

    PubMed Central

    Andoh, Masako; Sakata, Akiko; Takano, Ai; Kawabata, Hiroki; Fujita, Hiromi; Une, Yumi; Goka, Koichi; Kishimoto, Toshio; Ando, Shuji

    2015-01-01

    One of the major routes of transmission of rickettsial and ehrlichial diseases is via ticks that infest numerous host species, including humans. Besides mammals, reptiles and amphibians also carry ticks that may harbor Rickettsia and Ehrlichia strains that are pathogenic to humans. Furthermore, reptiles and amphibians are exempt from quarantine in Japan, thus facilitating the entry of parasites and pathogens to the country through import. Accordingly, in the current study, we examined the presence of Rickettsia and Ehrlichia spp. genes in ticks associated with reptiles and amphibians originating from outside Japan. Ninety-three ticks representing nine tick species (genera Amblyomma and Hyalomma) were isolated from at least 28 animals spanning 10 species and originating from 12 countries (Ghana, Jordan, Madagascar, Panama, Russia, Sri Lanka, Sudan, Suriname, Tanzania, Togo, Uzbekistan, and Zambia). None of the nine tick species are indigenous in Japan. The genes encoding the common rickettsial 17-kDa antigen, citrate synthase (gltA), and outer membrane protein A (ompA) were positively detected in 45.2% (42/93), 40.9% (38/93), and 23.7% (22/93) of the ticks, respectively, by polymerase chain reaction (PCR). The genes encoding ehrlichial heat shock protein (groEL) and major outer membrane protein (omp-1) were PCR-positive in 7.5% (7/93) and 2.2% (2/93) of the ticks, respectively. The p44 gene, which encodes the Anaplasma outer membrane protein, was not detected. Phylogenetic analysis showed that several of the rickettsial and ehrlichial sequences isolated in this study were highly similar to human pathogen genes, including agents not previously detected in Japan. These data demonstrate the global transportation of pathogenic Rickettsia and Ehrlichia through reptile- and amphibian-associated ticks. These imported animals have potential to transfer pathogens into human life. These results highlight the need to control the international transportation of known and

  1. INFECTION BY Rickettsia felis IN OPOSSUMS (Didelphis sp.) FROM YUCATAN, MEXICO.

    PubMed

    Peniche-Lara, Gaspar; Ruiz-Piña, Hugo A; Reyes-Novelo, Enrique; Dzul-Rosado, Karla; Zavala-Castro, Jorge

    2016-01-01

    Rickettsia felis is an emergent pathogen and the causative agent of a typhus-like rickettsiosis in the Americas. Its transmission cycle involves fleas as biological vectors (mainly Ctenocephalides felis) and multiple domestic and synanthropic mammal hosts. Nonetheless, the role of mammals in the cycle of R. felis is not well understood and many efforts are ongoing in different countries of America to clarify it. The present study describes for the first time in Mexico the infection of two species of opossum (Didelphis virginiana and D. marsupialis) by R. felis. A diagnosis was carried out from blood samples by molecular methods through the gltA and 17 kDa genes and sequence determination. Eighty-seven opossum samples were analyzed and 28 were found to be infected (32.1%) from five out of the six studied localities of Yucatan. These findings enable recognition of the potential epidemiological implications for public health of the presence of infected synanthropic Didelphis in households. PMID:27074326

  2. INFECTION BY Rickettsia felis IN OPOSSUMS (Didelphis sp.) FROM YUCATAN, MEXICO

    PubMed Central

    PENICHE-LARA, Gaspar; RUIZ-PIÑA, Hugo A.; REYES-NOVELO, Enrique; DZUL-ROSADO, Karla; ZAVALA-CASTRO, Jorge

    2016-01-01

    Rickettsia felis is an emergent pathogen and the causative agent of a typhus-like rickettsiosis in the Americas. Its transmission cycle involves fleas as biological vectors (mainly Ctenocephalides felis) and multiple domestic and synanthropic mammal hosts. Nonetheless, the role of mammals in the cycle of R. felis is not well understood and many efforts are ongoing in different countries of America to clarify it. The present study describes for the first time in Mexico the infection of two species of opossum (Didelphis virginiana and D. marsupialis) by R. felis. A diagnosis was carried out from blood samples by molecular methods through the gltAand 17 kDa genes and sequence determination. Eighty-seven opossum samples were analyzed and 28 were found to be infected (32.1%) from five out of the six studied localities of Yucatan. These findings enable recognition of the potential epidemiological implications for public health of the presence of infected synanthropic Didelphis in households. PMID:27074326

  3. Molecular detection of Rickettsia, Borrelia, and Babesia species in Ixodes ricinus sampled in northeastern, central, and insular areas of Italy.

    PubMed

    Castro, Lyda R; Gabrielli, Simona; Iori, Albertina; Cancrini, Gabriella

    2015-07-01

    The aim of the present study was to provide insight into the diversity of tick-borne pathogens circulating in Italy, carried/transmitted by Ixodes ricinus, one of the most abundant tick species in the country. A total of 447 specimens sampled in five areas of northeastern, central and insular Italy were analysed by polymerase chain reaction and sequencing for the presence of rickettsiae, borreliae and babesiae. Several rickettsial species of the spotted fever group of zoonotic concern and other zoonotic pathogens were found, such as Borrelia burgdorferi s.s., Borrelia afzelii, Borrelia garinii, and Babesia venatorum. These findings confirm a wide distribution of tick-borne bacterial and protozoan species in Italy, and highlight the sanitary importance of I. ricinus, often recorded as feeding on humans. PMID:25784072

  4. Molecular characterization of 'Candidatus Rickettsia vini' in Ixodes arboricola from the Czech Republic and Slovakia.

    PubMed

    Novakova, Marketa; Bulkova, Alexandra; Costa, Francisco B; Kristin, Anton; Krist, Milos; Krause, Frantisek; Liznarova, Eva; Labruna, Marcelo B; Literak, Ivan

    2015-04-01

    The aim of this study was to analyze the prevalence of rickettsiae in the tree-hole tick Ixodes arboricola in the Czech Republic and Slovakia. During May to September of 2009 and 2013, bird boxes belonging to three different areas were screened for ticks. In total, 454 nestlings and 109 nests of 10 hole-breeding bird species were examined. Ticks were found on Ficedula albicollis, Parus major, Cyanistes caeruleus and Sitta europaea and/or in their nests. In total, 166 ticks (17 nymphs, 10 males and 139 females) were found at 3 areas (arithmetic mean±standard error: 55.3±45.9). All ticks were tested for the presence of Rickettsia species by polymerase chain reaction targeting the rickettsial genes gltA, ompA, ompB and htrA and amplicon sequencing. All individuals except 3 nymphs were infected with 'Candidatus Rickettsia vini'. Multilocus sequence typing showed closest proximity to Rickettsia japonica and Rickettsia heilongjiangensis cluster. The presence of 'Ca. R. vini' is reported for the first time in Slovakia. PMID:25769386

  5. The Facultative Symbiont Rickettsia Protects an Invasive Whitefly against Entomopathogenic Pseudomonas syringae Strains

    PubMed Central

    Hunter, Martha S.; Baltrus, David A.

    2014-01-01

    Facultative endosymbionts can benefit insect hosts in a variety of ways, including context-dependent roles, such as providing defense against pathogens. The role of some symbionts in defense may be overlooked, however, when pathogen infection is transient, sporadic, or asymptomatic. The facultative endosymbiont Rickettsia increases the fitness of the sweet potato whitefly (Bemisia tabaci) in some populations through mechanisms that are not yet understood. In this study, we investigated the role of Rickettsia in mediating the interaction between the sweet potato whitefly and Pseudomonas syringae, a common environmental bacterium, some strains of which are pathogenic to aphids. Our results show that P. syringae multiplies within whiteflies, leading to host death, and that whiteflies infected with Rickettsia show a decreased rate of death due to P. syringae. Experiments using plants coated with P. syringae confirmed that whiteflies can acquire the bacteria at a low rate while feeding, leading to increased mortality, particularly when the whiteflies are not infected with Rickettsia. These results suggest that P. syringae may affect whitefly populations in nature and that Rickettsia can ameliorate this effect. This study highlights the possible importance of interactions among opportunistic environmental pathogens and endosymbionts of insects. PMID:25217020

  6. Spotted fever group--Rickettsiae in the Tyrols: evidence by seroepidemiology and PCR.

    PubMed

    Sonnleitner, S T; Simeoni, J; Lang, S; Dobler, G; Speck, S; Zelger, R; Schennach, H; Lass-Flörl, C; Walder, G

    2013-06-01

    The aim of our study was to assess the occurrence of Rickettsia in the inner-alpine valleys of the Eastern Alps and to determine the amount of seroreaction among the local human population. Ticks were investigated by PCR and the percentage of seropositives was determined among local blood donors by an in-house immunofluorescence assay. The local cut-off titre for screening of IgG was set at 1 : 128 with a well-characterised low-risk collective according to WHO-guidelines. Positive sera were confirmed by independent re-testing. Rickettsia is present in ticks north and south of the continental divide. Of 259 ticks investigated, 12.4% are positive for Rickettsia. Of over 1200 blood donors tested so far, 7.7% bear IgG at a titre of 1 : 128 or higher against R. helvetica. R. helvetica is present in the study area, causes immunoreaction among local residents and is associated with anamnestic erythema. Furthermore, screening with a second Spotted Fever Group Rickettsia indicates that significant parts of the Tyrolean population are exposed to a Rickettsia other than R. helvetica. PMID:22883690

  7. Lysis of typhus-group rickettsia-infected targets by lymphokine activated killers

    SciTech Connect

    Carl, M.; Dasch, G.A.

    1986-03-01

    The authors recently described a subset of OKT8, OKT3-positive lymphocytes from typhus-group rickettsia immune individuals which were capable of lysing autologous PHA-blasts or Epstein-Barr virus transformed B cells (LCL) infected with typhus-group rickettsiae. In order to determine if killing by these effectors was HLA-restricted, they stimulated peripheral blood mononuclear cells (PBMC) from typhus-group rickettsia immune individuals in vitro with typhus-group rickettsia-derived antigen for one week and then measured lysis of autologous LCL or HLA-mismatched LCL in a 4-6 hour Cr/sup 51/-release assay. There was significant lysis of both the autologous and the HLA-mismatched infected targets as compared to the corresponding uninfected targets. Since this suggested that the effectors were lymphokine activated killers (LAK) rather than cytotoxic T lymphocytes, they then tested this hypothesis by stimulating PBMC from both immune and non-immune individuals in vitro for one week with purified interleukin 2 and measuring lysis of infected, autologous LCL. PBMC thus treated, from both immune and non-immune individuals, were capable of significantly lysing autologous, infected LCL as compared to the non-infected control. They therefore conclude that targets infected with typhus-group rickettsiae are susceptible to lysis to LAK.

  8. Outbreak of Rickettsia typhi infection - Austin, Texas, 2008.

    PubMed

    2009-11-20

    Murine typhus is a fleaborne rickettsial disease caused by the organism Rickettsia typhi. Symptoms include fever, headache, chills, vomiting, nausea, myalgia, and rash. Although murine typhus is endemic in southern Texas, only two cases had been reported during the past 10 years from Austin, located in central Texas. On August 8, 2008, the Austin/Travis County Department of Health and Human Services (ATCDHHS) contacted the Texas Department of State Health Services (TDSHS) concerning a cluster of 14 illnesses with serologic findings indicative of murine typhus. On August 12, 2008, TDSHS initiated an investigation with assistance from CDC to characterize the magnitude of the outbreak and assess potential animal reservoirs and peridomestic factors that might have contributed to disease. This report summarizes the clinical and environmental findings of that investigation. Thirty-three confirmed cases involved illness comparable to that associated with previous outbreaks of murine typhus. Illness ranged from mild to severe, with 73% of patients requiring hospitalization. Delayed diagnosis and administration of no or inappropriate antibiotics might have contributed to illness severity. Environmental investigation suggested that opossums and domestic animals likely played a role in the maintenance and spread of R. typhi; however, their precise role in the outbreak has not been determined. These findings underscore the need to increase awareness of murine typhus and communicate appropriate treatment and prevention measures through the distribution of typhus alerts before and throughout the peak vector season of March-November. PMID:19940832

  9. Transmission potential of Rickettsia felis infection by Anopheles gambiae mosquitoes

    PubMed Central

    Dieme, Constentin; Bechah, Yassina; Socolovschi, Cristina; Audoly, Gilles; Berenger, Jean-Michel; Faye, Ousmane; Raoult, Didier; Parola, Philippe

    2015-01-01

    A growing number of recent reports have implicated Rickettsia felis as a human pathogen, paralleling the increasing detection of R. felis in arthropod hosts across the globe, primarily in fleas. Here Anopheles gambiae mosquitoes, the primary malarial vectors in sub-Saharan Africa, were fed with either blood meal infected with R. felis or infected cellular media administered in membrane feeding systems. In addition, a group of mosquitoes was fed on R. felis-infected BALB/c mice. The acquisition and persistence of R. felis in mosquitoes was demonstrated by quantitative PCR detection of the bacteria up to day 15 postinfection. R. felis was detected in mosquito feces up to day 14. Furthermore, R. felis was visualized by immunofluorescence in salivary glands, in and around the gut, and in the ovaries, although no vertical transmission was observed. R. felis was also found in the cotton used for sucrose feeding after the mosquitoes were fed infected blood. Natural bites from R. felis-infected An. gambiae were able to cause transient rickettsemias in mice, indicating that this mosquito species has the potential to be a vector of R. felis infection. This is particularly important given the recent report of high prevalence of R. felis infection in patients with “fever of unknown origin” in malaria-endemic areas. PMID:26056256

  10. Common Epidemiology of Rickettsia felis Infection and Malaria, Africa

    PubMed Central

    Mediannikov, Oleg; Socolovschi, Cristina; Edouard, Sophie; Fenollar, Florence; Mouffok, Nadjet; Bassene, Hubert; Diatta, Georges; Tall, Adama; Niangaly, Hamidou; Doumbo, Ogobara; Lekana-Douki, Jean Bernard; Znazen, Abir; Sarih, M’hammed; Ratmanov, Pavel; Richet, Herve; Ndiath, Mamadou O.; Sokhna, Cheikh; Parola, Philippe

    2013-01-01

    This study aimed to compare the epidemiology of Rickettsia felis infection and malaria in France, North Africa, and sub-Saharan Africa and to identify a common vector. Blood specimens from 3,122 febrile patients and from 500 nonfebrile persons were analyzed for R. felis and Plasmodium spp. We observed a significant linear trend (p<0.0001) of increasing risk for R. felis infection. The risks were lowest in France, Tunisia, and Algeria (1%), and highest in rural Senegal (15%). Co-infections with R. felis and Plasmodium spp. and occurrences of R. felis relapses or reinfections were identified. This study demonstrates a correlation between malaria and R. felis infection regarding geographic distribution, seasonality, asymptomatic infections, and a potential vector. R. felis infection should be suspected in these geographical areas where malaria is endemic. Doxycycline chemoprophylaxis against malaria in travelers to sub-Saharan Africa also protects against rickettsioses; thus, empirical treatment strategies for febrile illness for travelers and residents in sub-Saharan Africa may require reevaluation. PMID:24188709

  11. Ectoparasite Infestations and Canine Infection by Rickettsiae and Ehrlichiae in a Semi-Arid Region of Northeastern Brazil.

    PubMed

    Araes-Santos, Ana Isabel; Moraes-Filho, Jonas; Peixoto, Renata M; Spolidorio, Mariana G; Azevedo, Sérgio S; Costa, Mateus M; Labruna, Marcelo B; Horta, Mauricio C

    2015-11-01

    This study investigated the prevalence of Rickettsia spp. and Ehrlichia canis infection in dogs and their ectoparasites from rural and urban areas of two municipalities, Petrolina and Juazeiro, within a semiarid region (Caatinga biome) of northeastern Brazil, by immunofluorescence assay (IFA) and polymerase chain reaction (PCR). Overall, 12.1% (61/504) and 23.0% (116/504) of canine plasma samples had antibodies reactive to Rickettsia spp. and E. canis. E. canis DNA was detected by PCR in 8.3% (42/504) of canine blood samples, whereas no blood sample was positive for Rickettsia spp. The infection by E. canis was determined by PCR in 4.9% (14/285) Rhipicephalus sanguineus sensu lato (s.l.) ticks and by Rickettsia felis in 1.1% (3/285) and 40.6% (74/182) ticks and fleas, respectively. Multivariate regression analyses revealed that canine seropositivity to Rickettsia spp. was associated statistically with the variables "to reside in Petrolina" and "presence of ectoparasites." Our results indicate that canine infection by E. canis might be endemic in the Caatinga biome as it is in other Brazilian biomes. Although no previous serosurvey for Rickettsia spp. has been conducted on dogs from the Caatinga biome, our values are much lower than the ones reported for rural dogs from other Brazilian biomes. These differences are likely related to the semiarid climate of the aatinga biome, which minimizes the exposure of rural dogs to Amblyomma spp. ticks, the most common vectors of Rickettsia spp. in Brazil. Considering that dogs are excellent sentinels for human exposure to Rickettsia spp., we can infer that the risks of human acquiring tick-borne rickettsiosis in the Caatinga region of the present study are low. The rickettsial infection rates in fleas and ticks were not related to canine seropositivity; i.e., areas with higher Rickettsia infection rates in fleas had the lowest canine seroreactivity to Rickettsia spp. PMID:26565771

  12. Molecular Detection and Identification of Spotted Fever Group Rickettsiae in Ticks Collected from the West Bank, Palestinian Territories

    PubMed Central

    Ereqat, Suheir; Nasereddin, Abedelmajeed; Al-Jawabreh, Amer; Azmi, Kifaya; Harrus, Shimon; Mumcuoglu, Kosta; Apanaskevich, Dimtry; Abdeen, Ziad

    2016-01-01

    Background Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group (SFG) rickettsiae. Although Spotted Fever is prevalent in the Middle East, no reports for the presence of tick-borne pathogens are available or any studies on the epidemiology of this disease in the West Bank. We aimed to identify the circulating hard tick vectors and genetically characterize SFG Rickettsia species in ixodid ticks from the West Bank-Palestinian territories. Methodology/Principal Findings A total of 1,123 ixodid ticks belonging to eight species (Haemaphysalis parva, Haemaphysalis adleri, Rhipicephalus turanicus, Rhipicephalus sanguineus, Rhipicephalus bursa, Hyalomma dromedarii, Hyalomma aegyptium and Hyalomma impeltatum) were collected from goats, sheep, camels, dogs, a wolf, a horse and a tortoise in different localities throughout the West Bank during the period of January-April, 2014. A total of 867 ticks were screened for the presence of rickettsiae by PCR targeting a partial sequence of the ompA gene followed by sequence analysis. Two additional genes, 17 kDa and 16SrRNA were also targeted for further characterization of the detected Rickettsia species. Rickettsial DNA was detected in 148 out of the 867 (17%) tested ticks. The infection rates in Rh. turanicus, Rh. sanguineus, H. adleri, H. parva, H. dromedarii, and H. impeltatum ticks were 41.7, 11.6, 16.7, 16.2, 11.8 and 20%, respectively. None of the ticks, belonging to the species Rh. bursa and H. aegyptium, were infected. Four SFG rickettsiae were identified: Rickettsia massiliae, Rickettsia africae, Candidatus Rickettsia barbariae and Candidatus Rickettsia goldwasserii. Significance The results of this study demonstrate the geographic distribution of SFG rickettsiae and clearly indicate the presence of at least four of them in collected ticks. Palestinian clinicians should be aware of emerging tick-borne diseases in the West Bank, particularly infections due to R

  13. [Microbiological diagnosis of emerging bacterial pathogens: Anaplasma, Bartonella, Rickettsia, and Tropheryma whipplei].

    PubMed

    Blanco, José Ramón; Jado, Isabel; Marín, Mercedes; Sanfeliu, Isabel; Portillo, Aránzazu; Anda, Pedro; Pons, Immaculada; Oteo, José Antonio

    2008-11-01

    Ehrlichia/Anaplasma, Bartonella, Rickettsia and Tropheryma whipplei (formerly called whippelii) are fastidious bacterial organisms, considered the causative agents of potentially severe emerging and re-emerging diseases with repercussions on public health. The recent availability of advanced molecular biology and cell culture techniques has led to the implication of many of these species in human pathologies. These issues are extensively covered in number 27 of the SEIMC microbiological procedure: Diagnóstico microbiológico de las infecciones por patógenos bacterianos emergentes: Anaplasma, Bartonella, Rickettsia y Tropheryma whippelii (Microbiological diagnosis of Anaplasma, Bartonella, Rickettsia and Tropheryma whippelii infections) (2nd ed., 2007) (www.seimc.org/documentos/protocolos/microbiologia/). PMID:19100178

  14. Detection of Rickettsia africae in Rhipicephalus (Boophilus) decoloratus ticks from the Republic of Botswana, South Africa.

    PubMed

    Portillo, Aránzazu; Pérez-Martínez, Laura; Santibáñez, Sonia; Blanco, José R; Ibarra, Valvanera; Oteo, José A

    2007-08-01

    A total of 53 engorged adult ticks belonging to the species Rhipicephalus (Boophilus) decoloratus (N = 9), Rhipicephalus evertsi evertsi (N = 27), Rhipicephalus appendiculatus (N = 9), Amblyomma hebraeum (N = 5), and Hyalomma marginatum turanicum (N = 3), were removed from oryx in Botswana (South Africa). They were tested for the presence of spotted fever group (SFG) Rickettsia and Anaplasma phagocytophilum using polymerase chain reaction (PCR). Seventy-seven percent of R. decoloratus as well as twenty percent of A. hebraeum were positive for ompA, gltA and 16S rRNA SFG Rickettsia PCR assays. All nucleotide sequences were homologous to Rickettsia africae, the agent of African tick-bite fever (ATBF). None of the tested ticks was positive for 16S rRNA A. phagocytophilum PCR assays. These results suggest for the first time that R. decoloratus ticks may be reservoirs of R. africae, and support the ATBF risk in this area. PMID:17690416

  15. Differences in Intracellular Fate of Two Spotted Fever Group Rickettsia in Macrophage-Like Cells

    PubMed Central

    Curto, Pedro; Simões, Isaura; Riley, Sean P.; Martinez, Juan J.

    2016-01-01

    Spotted fever group (SFG) rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (Rickettsia conorii) and Rocky Mountain spotted fever (Rickettsia rickettsii). Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickettsial diseases. These studies raise the hypothesis that the role of macrophages in rickettsial pathogenesis may have been underappreciated. Herein, we evaluated the ability of two SFG rickettsial species, R. conorii (a recognized human pathogen) and Rickettsia montanensis (a non-virulent member of SFG) to proliferate in THP-1 macrophage-like cells, or within non-phagocytic cell lines. Our results demonstrate that R. conorii was able to survive and proliferate in both phagocytic and epithelial cells in vitro. In contrast, R. montanensis was able to grow in non-phagocytic cells, but was drastically compromised in the ability to proliferate within both undifferentiated and PMA-differentiated THP-1 cells. Interestingly, association assays revealed that R. montanensis was defective in binding to THP-1-derived macrophages; however, the invasion of the bacteria that are able to adhere did not appear to be affected. We have also demonstrated that R. montanensis which entered into THP-1-derived macrophages were rapidly destroyed and partially co-localized with LAMP-2 and cathepsin D, two markers of lysosomal compartments. In contrast, R. conorii was present as intact bacteria and free in the cytoplasm in both cell types. These findings suggest that a phenotypic difference between a non-pathogenic and a pathogenic SFG member lies in their respective ability to proliferate in macrophage-like cells, and may provide an explanation as to why certain SFG rickettsial species are not associated

  16. Production of monoclonal antibodies against Rickettsia massiliae and their use in antigenic and epidemiological studies.

    PubMed Central

    Xu, W; Raoult, D

    1997-01-01

    Rickettsiae are gram-negative, obligate intracellular bacteria which have historically been divided into three groups: the typhus group, the scrub typhus group, and the spotted fever group (SFG). Recently, several new SFG rickettsiae have been characterized, and most of these species are associated with ticks and have, as yet, no known pathogenicity toward humans. Rickettsia massiliae, which is widely distributed in Europe and Africa, is one such rickettsia. In order to investigate the antigenic relationships between R. massiliae and other rickettsial species and to develop a more convenient methodology for identifying R. massiliae, we produced monoclonal antibodies against the type strain (Mtu1T) of R. massiliae by fusing immunized splenocytes with SP2/0-Ag14 myeloma cells. A panel of 16 representatives were selected from the 163 positive hybridomas identified on initial screening, and their secreted monoclonal antibodies were further characterized. The reactivities of these 16 monoclonal antibodies with a large panel of rickettsial species were assessed by the microimmunofluorescence assay. All species of the SFG rickettsiae reacted with the monoclonal antibodies directed against epitopes on lipopolysaccharide, which is the common antigen among the SFG rickettsiae. Some closely related species of the SFG, such as Bar29, "R. aeschlimanni," and R. rhipicephali, showed strong cross-reactivities with the monoclonal antibodies directed against epitopes on the two major high-molecular-mass heat-labile proteins (106 and 120 kDa). In addition, species-specific monoclonal antibodies demonstrated that R. massiliae is antigenically different from other rickettsial species. Moreover, these species-specific monoclonal antibodies were successfully used for identifying R. massiliae in the ticks collected from southern France, and are therefore potentially useful tools in the identification and investigation of R. massiliae in ticks in large-scale field work. PMID:9196180

  17. Amblyomma maculatum Feeding Augments Rickettsia parkeri Infection in a Rhesus Macaque Model: A Pilot Study.

    PubMed

    Banajee, Kaikhushroo H; Embers, Monica E; Langohr, Ingeborg M; Doyle, Lara A; Hasenkampf, Nicole R; Macaluso, Kevin R

    2015-01-01

    Rickettsia parkeri is an emerging eschar-causing human pathogen in the spotted fever group of Rickettsia and is transmitted by the Gulf coast tick, Amblyomma maculatum. Tick saliva has been shown to alter both the cellular and humoral components of the innate and adaptive immune systems. However, the effect of this immunomodulation on Rickettsia transmission and pathology in an immunocompetent vertebrate host has not been fully examined. We hypothesize that, by modifying the host immune response, tick feeding enhances infection and pathology of pathogenic spotted fever group Rickettsia sp. In order to assess this interaction in vivo, a pilot study was conducted using five rhesus macaques that were divided into three groups. One group was intradermally inoculated with low passage R. parkeri (Portsmouth strain) alone (n = 2) and another group was inoculated during infestation by adult, R. parkeri-free A. maculatum (n = 2). The final macaque was infested with ticks alone (tick feeding control group). Blood, lymph node and skin biopsies were collected at several time points post-inoculation/infestation to assess pathology and quantify rickettsial DNA. As opposed to the tick-only animal, all Rickettsia-inoculated macaques developed inflammatory leukograms, elevated C-reactive protein concentrations, and elevated TH1 (interferon-γ, interleukin-15) and acute phase inflammatory cytokines (interleukin-6) post-inoculation, with greater neutrophilia and interleukin-6 concentrations in the tick plus R. parkeri group. While eschars formed at all R. parkeri inoculation sites, larger and slower healing eschars were observed in the tick feeding plus R. parkeri group. Furthermore, dissemination of R. parkeri to draining lymph nodes early in infection and increased persistence at the inoculation site were observed in the tick plus R. parkeri group. This study indicates that rhesus macaques can be used to model R. parkeri rickettsiosis, and suggests that immunomodulatory factors

  18. Amblyomma maculatum Feeding Augments Rickettsia parkeri Infection in a Rhesus Macaque Model: A Pilot Study

    PubMed Central

    Banajee, Kaikhushroo H.; Embers, Monica E.; Langohr, Ingeborg M.; Doyle, Lara A.; Hasenkampf, Nicole R.; Macaluso, Kevin R.

    2015-01-01

    Rickettsia parkeri is an emerging eschar-causing human pathogen in the spotted fever group of Rickettsia and is transmitted by the Gulf coast tick, Amblyomma maculatum. Tick saliva has been shown to alter both the cellular and humoral components of the innate and adaptive immune systems. However, the effect of this immunomodulation on Rickettsia transmission and pathology in an immunocompetent vertebrate host has not been fully examined. We hypothesize that, by modifying the host immune response, tick feeding enhances infection and pathology of pathogenic spotted fever group Rickettsia sp. In order to assess this interaction in vivo, a pilot study was conducted using five rhesus macaques that were divided into three groups. One group was intradermally inoculated with low passage R. parkeri (Portsmouth strain) alone (n = 2) and another group was inoculated during infestation by adult, R. parkeri-free A. maculatum (n = 2). The final macaque was infested with ticks alone (tick feeding control group). Blood, lymph node and skin biopsies were collected at several time points post-inoculation/infestation to assess pathology and quantify rickettsial DNA. As opposed to the tick-only animal, all Rickettsia-inoculated macaques developed inflammatory leukograms, elevated C-reactive protein concentrations, and elevated TH1 (interferon-γ, interleukin-15) and acute phase inflammatory cytokines (interleukin-6) post-inoculation, with greater neutrophilia and interleukin-6 concentrations in the tick plus R. parkeri group. While eschars formed at all R. parkeri inoculation sites, larger and slower healing eschars were observed in the tick feeding plus R. parkeri group. Furthermore, dissemination of R. parkeri to draining lymph nodes early in infection and increased persistence at the inoculation site were observed in the tick plus R. parkeri group. This study indicates that rhesus macaques can be used to model R. parkeri rickettsiosis, and suggests that immunomodulatory factors

  19. Tick cell culture isolation and growth of Rickettsia raoultii from Dutch Dermacentor reticulatus ticks

    PubMed Central

    Alberdi, M. Pilar; Nijhof, Ard M.; Jongejan, Frans; Bell-Sakyi, Lesley

    2012-01-01

    Tick cell lines play an important role in research on ticks and tick-borne pathogenic and symbiotic microorganisms. In an attempt to derive continuous Dermacentor reticulatus cell lines, embryo-derived primary cell cultures were set up from eggs laid by field ticks originally collected as unfed adults in The Netherlands and maintained for up to 16 months. After several months, it became evident that cells in the primary cultures were infected with a Rickettsia-like intracellular organism. Supernatant medium containing some D. reticulatus cells was inoculated into cultures of 2 Rhipicephalus (Boophilus) microplus cell lines, BME/CTVM2 and BME/CTVM23, where abundant growth of the bacteria occurred intracellularly on transfer to both cell lines. Bacterial growth was monitored by light (live, inverted microscope, Giemsa-stained cytocentrifuge smears) and transmission electron microscopy revealing heavy infection with typical intracytoplasmic Rickettsia-like bacteria, not present in uninfected cultures. DNA was extracted from bacteria-infected and uninfected control cultures, and primers specific for Rickettsia 16S rRNA, ompB, and sca4 genes were used to generate PCR products that were subsequently sequenced. D. reticulatus primary cultures and both infected tick cell lines were positive for all 3 Rickettsia genes. Sequencing of PCR products revealed 99–100% identity with published Rickettsia raoultii sequences. The R. raoultii also grew abundantly in the D. nitens cell line ANE58, poorly in the D. albipictus cell line DALBE3, and not at all in the D. andersoni cell line DAE15. In conclusion, primary tick cell cultures and cell lines are useful systems for isolation and propagation of fastidious tick-borne microorganisms. In vitro isolation of R. raoultii from Dutch D. reticulatus confirms previous PCR-based detection in field ticks, and presence of the bacteria in the tick eggs used to initiate the primary cultures confirms that transovarial transmission of this

  20. Differences in Intracellular Fate of Two Spotted Fever Group Rickettsia in Macrophage-Like Cells.

    PubMed

    Curto, Pedro; Simões, Isaura; Riley, Sean P; Martinez, Juan J

    2016-01-01

    Spotted fever group (SFG) rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (Rickettsia conorii) and Rocky Mountain spotted fever (Rickettsia rickettsii). Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickettsial diseases. These studies raise the hypothesis that the role of macrophages in rickettsial pathogenesis may have been underappreciated. Herein, we evaluated the ability of two SFG rickettsial species, R. conorii (a recognized human pathogen) and Rickettsia montanensis (a non-virulent member of SFG) to proliferate in THP-1 macrophage-like cells, or within non-phagocytic cell lines. Our results demonstrate that R. conorii was able to survive and proliferate in both phagocytic and epithelial cells in vitro. In contrast, R. montanensis was able to grow in non-phagocytic cells, but was drastically compromised in the ability to proliferate within both undifferentiated and PMA-differentiated THP-1 cells. Interestingly, association assays revealed that R. montanensis was defective in binding to THP-1-derived macrophages; however, the invasion of the bacteria that are able to adhere did not appear to be affected. We have also demonstrated that R. montanensis which entered into THP-1-derived macrophages were rapidly destroyed and partially co-localized with LAMP-2 and cathepsin D, two markers of lysosomal compartments. In contrast, R. conorii was present as intact bacteria and free in the cytoplasm in both cell types. These findings suggest that a phenotypic difference between a non-pathogenic and a pathogenic SFG member lies in their respective ability to proliferate in macrophage-like cells, and may provide an explanation as to why certain SFG rickettsial species are not associated

  1. Detection of Rickettsia felis in Wild Mammals from Three Municipalities in Yucatan, Mexico.

    PubMed

    Panti-May, Jesús Alonso; Torres-Castro, Marco; Hernández-Betancourt, Silvia; Dzul-Rosado, Karla; Zavala-Castro, Jorge; López-Avila, Karina; Tello-Martín, Raúl

    2015-09-01

    The aim of this study was to provide information of the occurrence of Rickettsia felis in wild mammals from three municipalities in Yucatan, Mexico. The reactivity of rodent serum to Rickettsia antigens was detected in 80.9% (17 of 21) samples using immunofluorescence assay. Polymerase chain reaction identified rickettsial DNA in spleens of 43.5% (10 of 23) rodents and 57.1% (4 of 7) opossums. The identification of the rickettsial DNA was confirmed as R. felis by restriction fragment length polymorphism and DNA sequencing. This study comprises the first report of R. felis detection in wild mammals in Yucatan. PMID:25537628

  2. Survey for Hantaviruses, Tick-Borne Encephalitis Virus, and Rickettsia spp. in Small Rodents in Croatia

    PubMed Central

    Dobler, Gerhard; Markotić, Alemka; Kurolt, Ivan-Christian; Speck, Stephanie; Habuš, Josipa; Vucelja, Marko; Krajinović, Lidija Cvetko; Tadin, Ante; Margaletić, Josip; Essbauer, Sandra

    2014-01-01

    Abstract In Croatia, several rodent- and vector-borne agents are endemic and of medical importance. In this study, we investigated hantaviruses and, for the first time, tick-borne encephalitis virus (TBEV) and Rickettsia spp. in small wild rodents from two different sites (mountainous and lowland region) in Croatia. In total, 194 transudate and tissue samples from 170 rodents (A. flavicollis, n=115; A. agrarius, n=2; Myodes glareolus, n=53) were tested for antibodies by indirect immunoflourescence assays (IIFT) and for nucleic acids by conventional (hantaviruses) and real-time RT-/PCRs (TBEV and Rickettsia spp.). A total of 25.5% (24/94) of the rodents from the mountainous area revealed specific antibodies against hantaviruses. In all, 21.3% (20/94) of the samples from the mountainous area and 29.0% (9/31) from the lowland area yielded positive results for either Puumala virus (PUUV) or Dobrava–Belgrade virus (DOBV) using a conventional RT-PCR. All processed samples (n=194) were negative for TBEV by IIFT or real-time RT-PCR. Serological evidence of rickettsial infection was detected in 4.3% (4/94) rodents from the mountainous region. Another 3.2% (3/94) rodents were positive for Rickettsia spp. by real-time PCR. None of the rodents (n=76) from the lowland area were positive for Rickettsia spp. by real-time PCR. Dual infection of PUUV and Rickettsia spp. was found in one M. glareolus from the mountainous area by RT-PCR and real-time PCR, respectively. To our knowledge, this is the first detection of Rickettsia spp. in small rodents from Croatia. Phylogenetic analyses of S- and M-segment sequences obtained from the two study sites revealed well-supported subgroups in Croatian PUUV and DOBV. Although somewhat limited, our data showed occurrence and prevalence of PUUV, DOBV, and rickettsiae in Croatia. Further studies are warranted to confirm these data and to determine the Rickettsia species present in rodents in these areas. PMID:24866325

  3. Rickettsia amblyommii infecting Amblyomma sculptum in endemic spotted fever area from southeastern Brazil.

    PubMed

    Nunes, Emília de Carvalho; Vizzoni, Vinicius Figueiredo; Navarro, Daniel Leal; Iani, Felipe Campos de Melo; Durães, Liliane Silva; Daemon, Erik; Soares, Carlos Augusto Gomes; Gazeta, Gilberto Salles

    2015-12-01

    The Rickettsia bacteria include the aetiological agents for the human spotted fever (SF) disease. In the present study, a SF group Rickettsia amblyommii related bacterium was detected in a field collected Amblyomma sculptum (Amblyomma cajennense species complex) tick from a Brazilian SF endemic site in southeastern Brazil, in the municipality of Juiz de Fora, state of Minas Gerais. Genetic analysis based on genes ompA,ompB and htrA showed that the detected strain, named R. amblyommii str. JF, is related to the species R. amblyommii. PMID:26676317

  4. Rickettsia sp. strain colombianensi (Rickettsiales: Rickettsiaceae): a new proposed Rickettsia detected in Amblyomma dissimile (Acari: Ixodidae) from iguanas and free-living larvae ticks from vegetation.

    PubMed

    Miranda, Jorge; Portillo, Aránzazu; Oteo, José A; Mattar, Salim

    2012-07-01

    From January to December 2009, 55 Amblyomma dissimile (Koch) ticks removed from iguanas in the municipality of Monteria and 3,114 ticks [458 Amblyomma sp. larvae, 2,636 Rhipicephalus microplus (Canestrini) larvae and 20 Amblyomma sp. nymphs] collected over vegetation in Los Cordobas were included in the study. The ticks were pooled into groups from which DNA was extracted. For initial screening of Rickettsia sp., each pool was analyzed by gltA real-time polymerase chain reaction (PCR). Positive pools were further studied using gltA, ompA, and ompB conventional PCR assays. Sequencing and phylogenetic analysis were also conducted. Rickettsial DNA was found in 28 pools of ticks (16 A. dissimile pools and 12 free-living larvae pools) out of 113 (24.7%) using real-time PCR. The same 28 pools were also positive using conventional PCR assays aimed to amplify gltA, ompA, and ompB. For each gene analyzed, PCR products obtained from 4/28 pools (two pools of A. dissimile, one pool of Amblyomma sp. larvae and one pool of Rh. microplus larvae) were randomly chosen and sequenced twice. Nucleotide sequences generated were identical to each other for each of the rickettsial genes gltA, ompA, and ompB, and showed 99.4, 95.6, and 96.4% identity with those of Rickettsia tamurae. They were deposited in the GenBank database under accession numbers JF905456, JF905458, and JF905457, respectively. In conclusion, we present the first molecular evidence of a novel Rickettsia (Rickettsia sp. strain Colombianensi) infecting A. dissimile ticks collected from iguanas, and also Rh. microplus and unspeciated Amblyomma larvae from vegetation in Colombia. PMID:22897060

  5. A novel spotted fever group Rickettsia infecting Amblyomma parvitarsum (Acari: Ixodidae) in highlands of Argentina and Chile.

    PubMed

    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

    2016-04-01

    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. PMID:26826974

  6. Seroepidemiological survey of Rickettsia spp. in dogs from the endemic area of Rickettsia parkeri rickettsiosis in Uruguay.

    PubMed

    Lado, Paula; Costa, Francisco B; Verdes, José M; Labruna, Marcelo B; Venzal, José M

    2015-06-01

    Rickettsia parkeri rickettsiosis is a vector-borne zoonosis that occurs in some countries of the American continent. Following the first description and determination of the pathogenicity to humans in 2004 in USA, this bacterium has been reported in several South American countries. Human cases have been diagnosed in both Uruguay and Argentina in the past years. This study consisted in a serosurvey of 1000 domestic dogs living in the endemic area of rickettsiosis in Uruguay, where Amblyomma triste is the tick vector. Sera were analyzed by Indirect Immunofluorescence Assay (IFA), against antigens of three different rickettsial species: R. rhipicephali, R. felis and R. parkeri. It was determined that 20.3% of the dogs had antibodies that reacted to at least one of the three species tested, taking as cut off ≥64 titers. Furthermore, 140 of the seropositive dogs (14%) had a titer at least 4 times higher to R. parkeri than those of any of the other species, thus, it was considered that the immune response was stimulated by that species in particular. This is the first serological survey in primary hosts for adults of A. triste in Uruguay, and therefore the first prevalence values are reported. Adult A. triste ticks collected from the environment as well as from dogs were analyzed by PCR in order to confirm the current circulation of the agent in the area. In this matter, two out of 28 ticks from dogs, and 3 out of 53 ticks from the environment were positive, and the corresponding sequence analysis revealed 100% similarity with R. parkeri strain maculatum. PMID:25735816

  7. Draft Genome Sequence of a New Zealand Rickettsia-Like Organism Isolated from Farmed Chinook Salmon

    PubMed Central

    Draper, Jenny; Brosnahan, Cara L.; Orr, Della; McFadden, Andrew; Jones, Brian

    2016-01-01

    We report here the draft genome sequence of a rickettsia-like organism, isolated from a New Zealand Chinook salmon farm experiencing high mortality. The genome is approximately 3 Mb in size, has a G+C content of approximately 39.2%, and is predicted to contain 2,870 coding sequences. PMID:27365345

  8. Draft Genome Sequence of a New Zealand Rickettsia-Like Organism Isolated from Farmed Chinook Salmon.

    PubMed

    Gias, Edna; Draper, Jenny; Brosnahan, Cara L; Orr, Della; McFadden, Andrew; Jones, Brian

    2016-01-01

    We report here the draft genome sequence of a rickettsia-like organism, isolated from a New Zealand Chinook salmon farm experiencing high mortality. The genome is approximately 3 Mb in size, has a G+C content of approximately 39.2%, and is predicted to contain 2,870 coding sequences. PMID:27365345

  9. Detection of Rickettsia spp in Ticks by MALDI-TOF MS

    PubMed Central

    Yssouf, Amina; Almeras, Lionel; Terras, Jérôme; Socolovschi, Cristina; Raoult, Didier; Parola, Philippe

    2015-01-01

    Background Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has been shown to be an effective tool for the rapid identification of arthropods, including tick vectors of human diseases. Methodology/Principal Findings The objective of the present study was to evaluate the use of MALDI-TOF MS to identify tick species, and to determine the presence of rickettsia pathogens in the infected Ticks. Rhipicephalus sanguineus and Dermacentor marginatus Ticks infected or not by R. conorii conorii or R. slovaca, respectively, were used as experimental models. The MS profiles generated from protein extracts prepared from tick legs exhibited mass peaks that distinguished the infected and uninfected Ticks, and successfully discriminated the Rickettsia spp. A blind test was performed using Ticks that were laboratory-reared, collected in the field or removed from patients and infected or not by Rickettsia spp. A query against our in-lab arthropod MS reference database revealed that the species and infection status of all Ticks were correctly identified at the species and infection status levels. Conclusions/Significance Taken together, the present work demonstrates the utility of MALDI-TOF MS for a dual identification of tick species and intracellular bacteria. Therefore, MALDI-TOF MS is a relevant tool for the accurate detection of Rickettsia spp in Ticks for both field monitoring and entomological diagnosis. The present work offers new perspectives for the monitoring of other vector borne diseases that present public health concerns. PMID:25659152

  10. Prevalence of Rickettsia and Bartonella species in Spanish cats and their fleas.

    PubMed

    Gracia, María Jesús; Marcén, José Miguel; Pinal, Rocio; Calvete, Carlos; Rodes, Daniel

    2015-12-01

    The aim of this study was to determine the prevalence of Bartonella henselae, Rickettsia felis, and Rickettsia typhi in fleas and companion cats (serum and claws) and to assess their presence as a function of host, host habitat, and level of parasitism. Eighty-nine serum and claw samples and 90 flea pools were collected. Cat sera were assayed by IFA for Bartonella henselae and Rickettssia species IgG antibodies. Conventional PCRs were performed on DNA extracted from nails and fleas collected from cats. A large portion (55.8%) of the feline population sampled was exposed to at least one of the three tested vector-borne pathogens. Seroreactivity to B. henselae was found in 50% of the feline studied population, and to R. felis in 16.3%. R. typhi antibodies were not found in any cat. No Bartonella sp. DNA was amplified from the claws. Flea samples from 41 cats (46%) showed molecular evidence for at least one pathogen; our study demonstrated a prevalence rate of 43.3 % of Rickettsia sp and 4.4% of Bartonella sp. in the studied flea population. None of the risk factors studied (cat's features, host habitat, and level of parasitation) was associated with either the serology or the PCR results for Bartonella sp. and Rickettsia sp.. Flea-associated infectious agents are common in cats and fleas and support the recommendation that stringent flea control should be maintained on cats. PMID:26611956

  11. Novel Candidatus Rickettsia Species Detected in Nostril Tick from Human, Gabon, 2014

    PubMed Central

    Lopez-Velez, Rogelio; Palomar, Ana M.; Oteo, José A.; Norman, Francesca F.; Pérez-Molina, José A.

    2015-01-01

    We report the identification of a nymphal nostril tick (Amblyomma sp.) from a national park visitor in Gabon and subsequent molecular detection and characterization of tickborne bacteria. Our findings provide evidence of a potentially new Rickettsia sp. circulating in Africa and indicate that tick bites may pose a risk to persons visiting parks in the region. PMID:25625886

  12. Rickettsia buchneri sp. nov., a rickettsial endosymbiont of the blacklegged tick Ixodes scapularis

    PubMed Central

    Felsheim, Roderick F.; Burkhardt, Nicole Y.; Oliver, Jonathan D.; Heu, Chan C.; Munderloh, Ulrike G.

    2015-01-01

    We obtained a rickettsial isolate from the ovaries of the blacklegged tick, Ixodes scapularis. The isolate (ISO7T) was grown in the Ixodes ricinus embryonic cell line IRE11. We characterized the isolate by transmission electron microscopy and gene sequencing. Phylogenetic analysis of 11 housekeeping genes demonstrated that the isolate fulfils the criteria to be classified as a representative of a novel rickettsial species closely related to ‘Rickettsia monacensis’. These rickettsiae form a clade separate from other species of rickettsiae. Gene sequences indicated that several genes important in rickettsial motility, invasiveness and temperature adaptation were mutated (e.g. sca2, rickA, hsp22, pldA and htrA). We propose the name Rickettsia buchneri sp. nov. for this bacterium that infects the ovaries of the tick I. scapularis to acknowledge the pioneering contributions of Professor Paul Buchner (1886–1978) to research on bacterial symbionts. The type strain of R. buchneri sp. nov. is strain ISO-7T ( = DSM 29016T = ATCC VR-1814T). PMID:25563918

  13. First report of Rickettsia raoultii in field collected Dermacentor reticulatus ticks from Austria.

    PubMed

    Duscher, Georg G; Hodžić, Adnan; Weiler, Martin; Vaux, Alexander G C; Rudolf, Ivo; Sixl, Wolfdieter; Medlock, Jolyon M; Versteirt, Veerle; Hubálek, Zdenek

    2016-07-01

    In a set of pooled field collected Dermacentor reticulatus ticks, Rickettsia raoultii, the causative agent of Tick-borne lymphadenopathy/Dermacentor-borne necrosis erythema and lymphadenopathy, was found for the first time in Austria. The coordinates of the positive locations for tick and pathogen abundance are given and shown in a map. PMID:26976704

  14. Pathogenic potential of a Costa Rican strain of 'Candidatus Rickettsia amblyommii' in guinea pigs (Cavia porcellus) and protective immunity against Rickettsia rickettsii.

    PubMed

    Rivas, Juan J; Moreira-Soto, Andrés; Alvarado, Gilberth; Taylor, Lizeth; Calderón-Arguedas, Olger; Hun, Laya; Corrales-Aguilar, Eugenia; Morales, Juan Alberto; Troyo, Adriana

    2015-09-01

    'Candidatus Rickettsia amblyommii' is a spotted fever group rickettsia that is not considered pathogenic, although there is serologic evidence of possible infection in animals and humans. The aim of this study was to evaluate the pathogenic potential of a Costa Rican strain of 'Candidatus R. amblyommii' in guinea pigs and determine its capacity to generate protective immunity against a subsequent infection with a local strain of Rickettsia rickettsii isolated from a human case. Six guinea pigs were inoculated with 'Candidatus R. amblyommii' strain 9-CC-3-1 and two controls with cell culture medium. Health status was evaluated, and necropsies were executed at days 2, 4, and 13. Blood and tissues were processed by PCR to detect the gltA gene, and end titers of anti-'Candidatus R. amblyommii' IgG were determined by indirect immunofluorescence. To evaluate protective immunity, another 5 guinea pigs were infected with 'Candidatus R. amblyommii' (IGPs). After 4 weeks, these 5 IGPs and 3 controls (CGPs) were inoculated with pathogenic R. rickettsii. Clinical signs and titers of anti-Rickettsia IgG were determined. IgG titers reached 1:512 at day 13 post-infection with 'Candidatus R. amblyommii'. On day 2 after inoculation, two guinea pigs had enlarged testicles and 'Candidatus R. amblyommii' DNA was detected in testicles. Histopathology confirmed piogranulomatous orchitis with perivascular inflammatory infiltrate in the epididymis. In the protective immunity assay, anti-Rickettsia IgG end titers after R. rickettsii infection were lower in IGPs than in CGPs. IGPs exhibited only transient fever, while CGP showed signs of severe disease and mortality. R. rickettsii was detected in testicles and blood of CGPs. Results show that the strain 9-CC-3-1 of 'Candidatus R. amblyommii' was able to generate pathology and an antibody response in guinea pigs. Moreover, its capacity to generate protective immunity against R. rickettsii may modulate the epidemiology and severity of Rocky

  15. Fast carry accumulator design

    NASA Technical Reports Server (NTRS)

    Mastin, W. C.

    1971-01-01

    Simple iterative accumulator combined with gated-carry, carry-completion detection, and skip-carry circuits produces three accumulators with decreased carry propagation times. Devices are used in machine control, measurement equipment, and computer applications to increase speed of binary addition. NAND gates are used in combining network.

  16. Analysis of Fluorescent Protein Expression in Transformants of Rickettsia monacensis, an Obligate Intracellular Tick Symbiont

    PubMed Central

    Baldridge, Gerald D.; Burkhardt, Nicole; Herron, Michael J.; Kurtti, Timothy J.; Munderloh, Ulrike G.

    2005-01-01

    We developed and applied transposon-based transformation vectors for molecular manipulation and analysis of spotted fever group rickettsiae, which are obligate intracellular bacteria that infect ticks and, in some cases, mammals. Using the Epicentre EZ::TN transposon system, we designed transposons for simultaneous expression of a reporter gene and a chloramphenicol acetyltransferase (CAT) resistance marker. Transposomes (transposon-transposase complexes) were electroporated into Rickettsia monacensis, a rickettsial symbiont isolated from the tick Ixodes ricinus. Each transposon contained an expression cassette consisting of the rickettsial ompA promoter and a green fluorescent protein (GFP) reporter gene (GFPuv) or the ompB promoter and a red fluorescent protein reporter gene (DsRed2), followed by the ompA transcription terminator and a second ompA promoter CAT gene cassette. Selection with chloramphenicol gave rise to rickettsial populations with chromosomally integrated single-copy transposons as determined by PCR, Southern blotting, and sequence analysis. Reverse transcription-PCR and Northern blots demonstrated transcription of all three genes. GFPuv transformant rickettsiae exhibited strong fluorescence in individual cells, but DsRed2 transformants did not. Western blots confirmed expression of GFPuv in R. monacensis and in Escherichia coli, but DsRed2 was expressed only in E. coli. The DsRed2 gene, but not the GFPuv gene, contains many GC-rich amino acid codons that are rare in the preferred codon suite of rickettsiae, possibly explaining the failure to express DsRed2 protein in R. monacensis. We demonstrated that our vectors provide a means to study rickettsia-host cell interactions by visualizing GFPuv-fluorescent R. monacensis associated with actin tails in tick host cells. PMID:15812043

  17. Transcriptional Analysis of the Conjugal Transfer Genes of Rickettsia bellii RML 369-C

    PubMed Central

    Heu, Chan C.; Kurtti, Timothy J.; Nelson, Curtis M.; Munderloh, Ulrike G.

    2015-01-01

    Rickettsia bellii is an obligate intracellular bacterium that is one of the few rickettsiae that encode a complete set of conjugative transfer (tra) genes involved in bacterial conjugation and has been shown to exhibit pili-like structures. The reductive genomes of rickettsiae beg the question whether the tra genes are nonfunctional or functioning to enhance the genetic plasticity and biology of rickettsiae. We characterized the transcriptional dynamics of R. bellii tra genes in comparison to genes transcribed stably and above the background level to understand when and at what levels the tra genes are active or whether the tra genes are degenerative. We determined that the best reference genes, out of 10 tested, were methionyl tRNA ligase (metG) or a combination of metG and ribonucleoside diphosphate reductase 2 subunit beta (nrdF), using statistical algorithms from two different programs: Normfinder and BestKeeper. To validate the use of metG with other rickettsial genes exhibiting variable transcriptional patterns we examined its use with sca2 and rickA, genes involved in actin based motility. Both were shown to be up-regulated at different times of replication in Vero cells, showing variable and stable transcription levels of rickA and sca2, respectively. traATi was up-regulated at 72 hours post inoculation in the tick cell line ISE6, but showed no apparent changes in the monkey cell line Vero and mouse cell line L929. The transcription of tra genes was positively correlated with one another and up-regulated from 12 to 72 hours post inoculation (HPI) when compared to RBE_0422 (an inactivated transposase-derivative found within the tra cluster). Thus, the up-regulation of the tra genes indicated that the integrity and activity of each gene were intact and may facilitate the search for the optimal conditions necessary to demonstrate conjugation in rickettsiae. PMID:26352829

  18. Spotted fever group Rickettsia in Amblyomma dubitatum tick from the urban area of Campo Grande, Mato Grosso do Sul, Brazil.

    PubMed

    Matias, Jaqueline; Garcia, Marcos Valério; Cunha, Rodrigo Casquero; Aguirre, André de Abreu Rangel; Barros, Jacqueline Cavalvante; Csordas, Bárbara Guimarães; Andreotti, Renato

    2015-03-01

    Rickettsia infection of each tick was evaluated by the hemolymph test and polymerase chain reaction (PCR) targeting gltA and ompA genes. All hemolymph tests were negative and PCR of one A. dubitatum detected both Rickettsia genes. Sequence of ompA exhibited a 99% identity with Rickettsia parkeri and R. africae and a 98% identity with R. sibirica. Rickettsia of the spotted fever group in A. dubitatum is described for the first time in an urban area within the municipality of Campo Grande in the state of Mato Grosso do Sul (MS), Brazil. This finding reinforces the importance of more detailed studies to determine the role of A. dubitatum in the transmission of spotted fever agents. PMID:25454606

  19. New Spotted Fever Group Rickettsia in a Rhipicephalus turanicus Tick Removed from a Child in Eastern Sicily, Italy

    PubMed Central

    Eremeeva, Marina E.; Stromdahl, Ellen Y.

    2011-01-01

    A new genotype of spotted fever group Rickettsia (SFGR) was identified in Rhipicephalus turanicus from eastern Sicily. On the basis of current molecular criteria, the genetic characteristics obtained from multiple locus sequence typing satisfy the requirements for Candidatus status of this SFGR. Further detection and identification of this SFGR during entomological and clinical surveys will be required to establish the prevalence of this Rickettsia and its potential pathogenicity for humans. PMID:21212209

  20. Rickettsia in synanthropic and domestic animals and their hosts from two areas of low endemicity for Brazilian spotted fever in the eastern region of Minas Gerais, Brazil.

    PubMed

    Milagres, Bruno S; Padilha, Amanda F; Barcelos, Rafael M; Gomes, Gabriel G; Montandon, Carlos E; Pena, Dárlen C H; Nieri Bastos, Fernanda A; Silveira, Iara; Pacheco, Richard; Labruna, Marcelo B; Bouyer, Donald H; Freitas, Renata N; Walker, David H; Mafra, Cláudio L; Galvao, Márcio A M

    2010-12-01

    The aim of this study was to understand the current epidemiology of rickettsial diseases in two rickettsial-endemic regions in Brazil. In the municipalities of Pingo D'Agua and Santa Cruz do Escalvado, among serum samples obtained from horses and dogs, reactivity by immunofluorescent assay against spotted fever group rickettsiae was verified. In some serum samples from opossums (Didelphis aurita) captured in Santa Cruz do Escalvado, serologic response against rickettsiae was also verified. Polymerase chain reaction identified rickettsiae only in ticks and fleas obtained in Santa Cruz do Escalvado. Rickettsiae in samples had 100% sequence homology with Rickettsia felis. These results highlight the importance of marsupials in maintenance of the sylvatic cycle of rickettsial disease and potential integration with the domestic cycle. Our data also support the importance of horses and dogs as sentinels in monitoring circulation of rickettsiae in an urban area. PMID:21118939

  1. Rickettsia in Synanthropic and Domestic Animals and Their Hosts from Two Areas of Low Endemicity for Brazilian Spotted Fever in the Eastern Region of Minas Gerais, Brazil

    PubMed Central

    Milagres, Bruno S.; Padilha, Amanda F.; Barcelos, Rafael M.; Gomes, Gabriel G.; Montandon, Carlos E.; Pena, Dárlen C. H.; Nieri Bastos, Fernanda A.; Silveira, Iara; Pacheco, Richard; Labruna, Marcelo B.; Bouyer, Donald H.; Freitas, Renata N.; Walker, David H.; Mafra, Cláudio L.; Galvao, Márcio A. M.

    2010-01-01

    The aim of this study was to understand the current epidemiology of rickettsial diseases in two rickettsial-endemic regions in Brazil. In the municipalities of Pingo D'Agua and Santa Cruz do Escalvado, among serum samples obtained from horses and dogs, reactivity by immunofluorescent assay against spotted fever group rickettsiae was verified. In some serum samples from opossums (Didelphis aurita) captured in Santa Cruz do Escalvado, serologic response against rickettsiae was also verified. Polymerase chain reaction identified rickettsiae only in ticks and fleas obtained in Santa Cruz do Escalvado. Rickettsiae in samples had 100% sequence homology with Rickettsia felis. These results highlight the importance of marsupials in maintenance of the sylvatic cycle of rickettsial disease and potential integration with the domestic cycle. Our data also support the importance of horses and dogs as sentinels in monitoring circulation of rickettsiae in an urban area. PMID:21118939

  2. A Rickettsia WASP-like protein activates the Arp2/3 complex and mediates actin-based motility.

    PubMed

    Jeng, Robert L; Goley, Erin D; D'Alessio, Joseph A; Chaga, Oleg Y; Svitkina, Tatyana M; Borisy, Gary G; Heinzen, Robert A; Welch, Matthew D

    2004-08-01

    Spotted fever group Rickettsia are obligate intracellular pathogens that exploit the host cell actin cytoskeleton to promote motility and cell-to-cell spread. Although other pathogens such as Listeria monocytogenes use an Arp2/3 complex-dependent nucleation mechanism to generate comet tails consisting of Y-branched filament arrays, Rickettsia polymerize tails consisting of unbranched filaments by a previously unknown mechanism. We identified genes in several Rickettsia species encoding proteins (termed RickA) with similarity to the WASP family of Arp2/3-complex activators. Rickettsia rickettsii RickA activated both the nucleation and Y-branching activities of the Arp2/3 complex like other WASP-family proteins, and was sufficient to direct the motility of microscopic beads in cell extracts. Actin tails generated by RickA-coated beads consisted of Y-branched filament networks. These data suggest that Rickettsia use an Arp2/3 complex-dependent actin-nucleation mechanism similar to that of other pathogens. We propose that additional Rickettsia or host factors reorganize the Y-branched networks into parallel arrays in a manner similar to a recently proposed model of filopodia formation. PMID:15236643

  3. Sympatric occurrence of Ixodes ricinus, Dermacentor reticulatus and Haemaphysalis concinna ticks and Rickettsia and Babesia species in Slovakia.

    PubMed

    Svehlová, Andrea; Berthová, Lenka; Sallay, Balázs; Boldiš, Vojtech; Sparagano, Olivier A E; Spitalská, Eva

    2014-09-01

    Vojka nad Dunajom in the south-west of the Slovak Republic is a locality with sympatric occurrence of 3 species of ticks. This study investigated the spatial distribution of Dermacentor reticulatus, Ixodes ricinus, and Haemaphysalis concinna ticks in this area and determined the prevalence of Babesia and Rickettsia species in questing adults of these tick species considered as potential risk for humans and animals. Ticks were collected by blanket dragging over the vegetation from September 2011 to October 2012. All ticks were subjected to DNA extraction and individually assayed with PCR-based methods targeting the gltA, sca4, 23S rRNA genes of Rickettsia spp. and the 18S rRNA gene of Babesia spp. D. reticulatus was the dominant species occurring in this area (67.7%, n=600), followed by I. ricinus (31.8%, n=282) and H. concinna (0.5%, n=4) ticks. Rickettsial infection was determined in 10.8% (n=65) and 11.7% (n=33) of D. reticulatus and I. ricinus ticks, respectively. Babesia spp. infection was confirmed in 1.8% (n=11) of D. reticulatus and 0.4% (n=1) of I. ricinus ticks. DNA of 6 different pathogenic tick-borne species, Rickettsia helvetica, Rickettsia monacensis, Rickettsia slovaca, Rickettsia raoultii, Babesia canis, and Babesia venatorum were identified in this locality with sympatric occurrence of I. ricinus, D. reticulatus, and H. concinna ticks. PMID:24973275

  4. An Anomalous Type IV Secretion System in Rickettsia Is Evolutionarily Conserved

    PubMed Central

    Gillespie, Joseph J.; Ammerman, Nicole C.; Dreher-Lesnick, Sheila M.; Rahman, M. Sayeedur; Worley, Micah J.; Setubal, Joao C.; Sobral, Bruno S.; Azad, Abdu F.

    2009-01-01

    Background Bacterial type IV secretion systems (T4SSs) comprise a diverse transporter family functioning in conjugation, competence, and effector molecule (DNA and/or protein) translocation. Thirteen genome sequences from Rickettsia, obligate intracellular symbionts/pathogens of a wide range of eukaryotes, have revealed a reduced T4SS relative to the Agrobacterium tumefaciens archetype (vir). However, the Rickettsia T4SS has not been functionally characterized for its role in symbiosis/virulence, and none of its substrates are known. Results Superimposition of T4SS structural/functional information over previously identified Rickettsia components implicate a functional Rickettsia T4SS. virB4, virB8 and virB9 are duplicated, yet only one copy of each has the conserved features of similar genes in other T4SSs. An extraordinarily duplicated VirB6 gene encodes five hydrophobic proteins conserved only in a short region known to be involved in DNA transfer in A. tumefaciens. virB1, virB2 and virB7 are newly identified, revealing a Rickettsia T4SS lacking only virB5 relative to the vir archetype. Phylogeny estimation suggests vertical inheritance of all components, despite gene rearrangements into an archipelago of five islets. Similarities of Rickettsia VirB7/VirB9 to ComB7/ComB9 proteins of ε-proteobacteria, as well as phylogenetic affinities to the Legionella lvh T4SS, imply the Rickettsiales ancestor acquired a vir-like locus from distantly related bacteria, perhaps while residing in a protozoan host. Modern modifications of these systems likely reflect diversification with various eukaryotic host cells. Conclusion We present the rvh (Rickettsiales vir homolog) T4SS, an evolutionary conserved transporter with an unknown role in rickettsial biology. This work lays the foundation for future laboratory characterization of this system, and also identifies the Legionella lvh T4SS as a suitable genetic model. PMID:19279686

  5. Orientia, rickettsia, and leptospira pathogens as causes of CNS infections in Laos: a prospective study

    PubMed Central

    Dittrich, Sabine; Rattanavong, Sayaphet; Lee, Sue J; Panyanivong, Phonepasith; Craig, Scott B; Tulsiani, Suhella M; Blacksell, Stuart D; Dance, David A B; Dubot-Pérès, Audrey; Sengduangphachanh, Amphone; Phoumin, Phonelavanh; Paris, Daniel H; Newton, Paul N

    2015-01-01

    Summary Background Scrub typhus (caused by Orientia tsutsugamushi), murine typhus (caused by Rickettsia typhi), and leptospirosis are common causes of febrile illness in Asia; meningitis and meningoencephalitis are severe complications. However, scarce data exist for the burden of these pathogens in patients with CNS disease in endemic countries. Laos is representative of vast economically poor rural areas in Asia with little medical information to guide public health policy. We assessed whether these pathogens are important causes of CNS infections in Laos. Methods Between Jan 10, 2003, and Nov 25, 2011, we enrolled 1112 consecutive patients of all ages admitted with CNS symptoms or signs requiring a lumbar puncture at Mahosot Hospital, Vientiane, Laos. Microbiological examinations (culture, PCR, and serology) targeted so-called conventional bacterial infections (Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, S suis) and O tsutsugamushi, Rickettsia typhi/Rickettsia spp, and Leptospira spp infections in blood or cerebrospinal fluid (CSF). We analysed and compared causes and clinical and CSF characteristics between patient groups. Findings 1051 (95%) of 1112 patients who presented had CSF available for analysis, of whom 254 (24%) had a CNS infection attributable to a bacterial or fungal pathogen. 90 (35%) of these 254 infections were caused by O tsutsugamushi, R typhi/Rickettsia spp, or Leptospira spp. These pathogens were significantly more frequent than conventional bacterial infections (90/1051 [9%] vs 42/1051 [4%]; p<0·0001) by use of conservative diagnostic definitions. CNS infections had a high mortality (236/876 [27%]), with 18% (13/71) for R typhi/Rickettsia spp, O tsutsugamushi, and Leptospira spp combined, and 33% (13/39) for conventional bacterial infections (p=0·076). Interpretation Our data suggest that R typhi/Rickettsia spp, O tsutsugamushi, and Leptospira spp infections are important causes of CNS infections in Laos

  6. Detection of Babesia Sp. EU1 and members of spotted fever group rickettsiae in ticks collected from migratory birds at Curonian Spit, North-Western Russia.

    PubMed

    Movila, Alexandru; Reye, Anna L; Dubinina, Helen V; Tolstenkov, Oleg O; Toderas, Ion; Hübschen, Judith M; Muller, Claude P; Alekseev, Andrey N

    2011-01-01

    To reveal the prevalence of spotted fever group (SFG) rickettsiae and Babesia sp. in Ixodes ricinus (L.) ticks from migratory birds, 236 specimens represented 8 species of Passeriformes and were collected at Curonian Spit in Kaliningrad enclave of North-Western Russia. The ticks (total 126) being detached from four bird species, Turdus philomelos, Fringilla coelebs, Parus major, and Sturnus vulgaris, were investigated by PCR using the primers Rp CS.877p/Rp CS.1258n for the detection of Rickettsia and BJ1/BN2 for Babesia spp. Babesia spp. were detected in 2 of 126 (1.6%) ticks. The partial sequence of 18S rDNA had 100% similarity to human pathogenic Babesia sp. EU1. The SFG rickettsiae were detected in 19 of 126 (15.1%) ticks collected from the above-mentioned bird species. BLAST analysis of SFG rickettsia gltA assigned sequences to human pathogenic Rickettsia helvetica (10.3%), Rickettsia monacensis (3.9%), and Rickettsia japonica (0.8%) with 98%-100% sequence similarity. The SFG rickettsiae and Babesia sp. EU1 in ticks collected from the passerines in Russia were detected for the first time. The survey indicates that migratory birds may become a reservoir for Babesia spp. and SFG rickettsiae. Future investigations need to characterize the role of birds in the epidemiology of these human pathogens in the region. PMID:20553110

  7. Defending the fort: a role for defensin-2 in limiting Rickettsia montanensis infection of Dermacentor variabilis

    PubMed Central

    Pelc, R S; McClure, J C; Sears, K T; Chung, A; Rahman, M S; Ceraul, S M

    2014-01-01

    The importance of tick defensins is evidenced by their expression in a wide variety of tick tissues and prevalence across many tick genera. To date, the functional and biological significance of defensin-2 as a rickettsiastatic or rickettsiacidal antimicrobial peptide has not been addressed. In a previous study, defensin-2 transcription was shown to increase in Dermacentor variabilis ticks challenged with Rickettsia montanensis. In the present study, the hypothesis that defensin-2 is functional as a rickettsiastatic and/or rickettsiacidal antimicrobial peptide is tested. We show that defensin-2 plays a role in reducing burden after acquisition of Rickettsia montanensis through capillary feeding. Moreover, defensin-2 is shown to associate with R. montanensis in vitro and in vivo, causing cytoplasmic leakiness. PMID:24779891

  8. Molecular detection of Rickettsia, Coxiella and Rickettsiella DNA in three native Australian tick species.

    PubMed

    Vilcins, Inger-Marie E; Old, Julie M; Deane, Elizabeth

    2009-11-01

    Three Australian native animal species yielded 60 samples composed of three indigenous ticks. Hosts included twelve koalas, two echidnas and one wombat from Victoria, and ticks were of the species Ixodes tasmani (n = 42), Bothriocroton concolor (n = 8) and B. auruginans (n = 10), respectively. PCR screening and sequencing detected a species of Coxiella, sharing closest sequence identity to C. burnetii (>98%), in all B. auruginans, as well as a species of Rickettsia, matching closest to R. massiliae, in 70% of the same samples. A genotype sharing closest similarity to Rickettsia bellii (>99%) was identified in three female B. concolor collected from one of the echidnas. Three samples of I. tasmani, taken from three koalas, yielded different genotypes of Rickettsiella. These results represent the first detection of the three genera in each tick species and identify a high level of previously undetected bacterial diversity in Australian ticks. PMID:19296229

  9. Tests on ticks from wild birds collected in the eastern United States for rickettsiae and viruses

    USGS Publications Warehouse

    Clifford, C.M.; Sonenshine, D.E.; Atwood, E.L.; Robbins, C.S.; Hughes, L.E.

    1969-01-01

    Results of tests for rickettsiae and viruses on 4,266 ticks taken from more than 10,000 birds, comprising 150 species, in the eastern United States indicated the presence of two agents: Rickettsia rickettsii and an agent of the typhus group. Infection with R. rickettsii was indicated in 24 pools of Haemaphysalis leporispalustris, five pools of Ixodes dentatus, one pool of Ixodes brunneus, and two pools that contained both I. dentatus and H. leporispalustris. The pools positive for R. rickettsii were from a variety of locations in the eastern U. S. The typhus-group agent was demonstrated only once, in a single pool of H. leporispalustris taken at Kent Point, Maryland. A strain of R. rickettsii was isolated from a pool of 21 larval H. leporispalustris collected at Ocean City, Maryland. This agent possessed several characteristics of other strains of low virulence isolated previously in this region by various authors.

  10. Genotypic comparison of five isolates of Rickettsia prowazekii by multilocus sequence typing.

    PubMed

    Ge, Hong; Tong, Min; Jiang, Ju; Dasch, Gregory A; Richards, Allen L

    2007-06-01

    Genetic traits of five Rickettsia prowazekii isolates, including the first from Africa and North America, and representatives from human and flying squirrels were compared using multilocus sequence typing. Four rickettsial genes encoding 17 kDa genus-common antigen (17 kDa gene), citrate synthase (gltA), OmpB immunodominant antigen (ompB) and 120 kDa cytoplasmic antigen (sca4) were examined. Sequence identities of 17 kDa gene and gltA were 100% among the isolates. Limited sequence diversity of ompB (0.02-0.11%) and sca4 (0.03-0.20%) was enough to distinguish the isolates, and evaluation of the combined four genes provided a method to easily differentiate R. prowazekii from other rickettsiae. PMID:17419766

  11. Molecular Investigations of Rickettsia helvetica Infection in Dogs, Foxes, Humans, and Ixodes Ticks▿

    PubMed Central

    Boretti, Felicitas S.; Perreten, Andrea; Meli, Marina L.; Cattori, Valentino; Willi, Barbara; Wengi, Nicole; Hornok, Sándor; Honegger, Hanspeter; Hegglin, Daniel; Woelfel, Roman; Reusch, Claudia E.; Lutz, Hans; Hofmann-Lehmann, Regina

    2009-01-01

    Rickettsia helvetica, a tick-borne member of the spotted-fever-group rickettsiae, is a suspected pathogen in humans; however, its role in animals is unknown. The aims of this study were to establish a R. helvetica-specific real-time TaqMan PCR assay and apply it to the analysis of tick vectors (to determine potential exposure risk) and blood samples from Canidae and humans (to determine prevalence of infection). The newly designed 23S rRNA gene assay for R. helvetica was more sensitive than a published citrate synthase gene (gltA) assay for several rickettsiae. Blood samples from 884 dogs, 58 foxes, and 214 human patients and 2,073 ticks (Ixodes spp.) collected from either vegetation or animals were analyzed. Although the maximal likelihood estimate of prevalence was 12% in unfed ticks and 36% in ticks collected from animals, none of the 1,156 blood samples tested PCR positive. Ticks from cats were more frequently PCR positive than ticks from dogs. Sequencing of the 23S rRNA and/or the gltA gene of 17 tick pools confirmed the presence of R. helvetica. Additionally, Rickettsia monacensis, which has not been previously found in Switzerland, was identified. In conclusion, R. helvetica was frequently detected in the tick population but not in blood samples. Nevertheless, due to the broad host range of Ixodes ticks and the high rate of infestation with this agent (i.e., R. helvetica was 13 times more frequent in unfed ticks than the tick-borne encephalitis virus), many mammals may be exposed to R. helvetica. The PCR assay described here represents an important tool for studying this topic. PMID:19329665

  12. Molecular Investigations of Rickettsia helvetica infection in dogs, foxes, humans, and Ixodes ticks.

    PubMed

    Boretti, Felicitas S; Perreten, Andrea; Meli, Marina L; Cattori, Valentino; Willi, Barbara; Wengi, Nicole; Hornok, Sándor; Honegger, Hanspeter; Hegglin, Daniel; Woelfel, Roman; Reusch, Claudia E; Lutz, Hans; Hofmann-Lehmann, Regina

    2009-05-01

    Rickettsia helvetica, a tick-borne member of the spotted-fever-group rickettsiae, is a suspected pathogen in humans; however, its role in animals is unknown. The aims of this study were to establish a R. helvetica-specific real-time TaqMan PCR assay and apply it to the analysis of tick vectors (to determine potential exposure risk) and blood samples from Canidae and humans (to determine prevalence of infection). The newly designed 23S rRNA gene assay for R. helvetica was more sensitive than a published citrate synthase gene (gltA) assay for several rickettsiae. Blood samples from 884 dogs, 58 foxes, and 214 human patients and 2,073 ticks (Ixodes spp.) collected from either vegetation or animals were analyzed. Although the maximal likelihood estimate of prevalence was 12% in unfed ticks and 36% in ticks collected from animals, none of the 1,156 blood samples tested PCR positive. Ticks from cats were more frequently PCR positive than ticks from dogs. Sequencing of the 23S rRNA and/or the gltA gene of 17 tick pools confirmed the presence of R. helvetica. Additionally, Rickettsia monacensis, which has not been previously found in Switzerland, was identified. In conclusion, R. helvetica was frequently detected in the tick population but not in blood samples. Nevertheless, due to the broad host range of Ixodes ticks and the high rate of infestation with this agent (i.e., R. helvetica was 13 times more frequent in unfed ticks than the tick-borne encephalitis virus), many mammals may be exposed to R. helvetica. The PCR assay described here represents an important tool for studying this topic. PMID:19329665

  13. Nonselective Persistence of a Rickettsia conorii Extrachromosomal Plasmid during Mammalian Infection.

    PubMed

    Riley, Sean P; Fish, Abigail I; Garza, Daniel A; Banajee, Kaikhushroo H; Harris, Emma K; del Piero, Fabio; Martinez, Juan J

    2016-03-01

    Scientific analysis of the genus Rickettsia is undergoing a rapid period of change with the emergence of viable genetic tools. The development of these tools for the mutagenesis of pathogenic bacteria will permit forward genetic analysis of Rickettsia pathogenesis. Despite these advances, uncertainty still remains regarding the use of plasmids to study these bacteria in in vivo mammalian models of infection, namely, the potential for virulence changes associated with the presence of extrachromosomal DNA and nonselective persistence of plasmids in mammalian models of infection. Here, we describe the transformation of Rickettsia conorii Malish 7 with the plasmid pRam18dRGA[AmTrCh]. Transformed R. conorii stably maintains this plasmid in infected cell cultures, expresses the encoded fluorescent proteins, and exhibits growth kinetics in cell culture similar to those of nontransformed R. conorii. Using a well-established murine model of fatal Mediterranean spotted fever, we demonstrate that R. conorii(pRam18dRGA[AmTrCh]) elicits the same fatal outcomes in animals as its untransformed counterpart and, importantly, maintains the plasmid throughout infection in the absence of selective antibiotic pressure. Interestingly, plasmid-transformed R. conorii was readily observed both in endothelial cells and within circulating leukocytes. Together, our data demonstrate that the presence of an extrachromosomal DNA element in a pathogenic rickettsial species does not affect either in vitro proliferation or in vivo infectivity in models of disease and that plasmids such as pRam18dRGA[AmTrCh] are valuable tools for the further genetic manipulation of pathogenic rickettsiae. PMID:26755154

  14. The Rickettsia conorii Autotransporter Protein Sca1 Promotes Adherence to Nonphagocytic Mammalian Cells ▿ †

    PubMed Central

    Riley, Sean P.; Goh, Kenneth C.; Hermanas, Timothy M.; Cardwell, Marissa M.; Chan, Yvonne G. Y.; Martinez, Juan J.

    2010-01-01

    The pathogenesis of spotted fever group (SFG) Rickettsia species, including R. conorii and R. rickettsii, is acutely dependent on adherence to and invasion of host cells, including cells of the mammalian endothelial system. Bioinformatic analyses of several rickettsia genomes revealed the presence of a cohort of genes designated sca genes that are predicted to encode proteins with homology to autotransporter proteins of Gram-negative bacteria. Previous work demonstrated that three members of this family, rOmpA (Sca0), Sca2, and rOmpB (Sca5) are involved in the interaction with mammalian cells; however, very little was known about the function of other conserved rickettsial Sca proteins. Here we demonstrate that sca1, a gene present in nearly all SFG rickettsia genomes, is actively transcribed and expressed in R. conorii cells. Alignment of Sca1 sequences from geographically diverse SFG Rickettsia species showed that there are high degrees of sequence identity and conservation of these sequences, suggesting that Sca1 may have a conserved function. Using a heterologous expression system, we demonstrated that production of R. conorii Sca1 in the Escherichia coli outer membrane is sufficient to mediate attachment to but not invasion of a panel of cultured mammalian epithelial and endothelial cells. Furthermore, preincubation of a recombinant Sca1 peptide with host cells blocked R. conorii cell association. Together, these results demonstrate that attachment to mammalian cells can be uncoupled from the entry process and that Sca1 is involved in the adherence of R. conorii to host cells. PMID:20176791

  15. Carrying Backpacks: Physical Effects

    ERIC Educational Resources Information Center

    Illinois State Board of Education, 2006

    2006-01-01

    It is estimated that more than 40 million U.S. youth carry school materials in backs, routinely carrying books, laptop computers, personal and other items used on a daily basis. The Consumer Product Safety Commission (CPSC) estimates that 7,277 emergency visits each year result from injuries related to backpacks. Injury can occur when a child…

  16. The Phylogeny of Rickettsia Using Different Evolutionary Signatures: How Tree-Like is Bacterial Evolution?

    PubMed Central

    Murray, Gemma G. R.; Weinert, Lucy A.; Rhule, Emma L.; Welch, John J.

    2016-01-01

    Rickettsia is a genus of intracellular bacteria whose hosts and transmission strategies are both impressively diverse, and this is reflected in a highly dynamic genome. Some previous studies have described the evolutionary history of Rickettsia as non-tree-like, due to incongruity between phylogenetic reconstructions using different portions of the genome. Here, we reconstruct the Rickettsia phylogeny using whole-genome data, including two new genomes from previously unsampled host groups. We find that a single topology, which is supported by multiple sources of phylogenetic signal, well describes the evolutionary history of the core genome. We do observe extensive incongruence between individual gene trees, but analyses of simulations over a single topology and interspersed partitions of sites show that this is more plausibly attributed to systematic error than to horizontal gene transfer. Some conflicting placements also result from phylogenetic analyses of accessory genome content (i.e., gene presence/absence), but we argue that these are also due to systematic error, stemming from convergent genome reduction, which cannot be accommodated by existing phylogenetic methods. Our results show that, even within a single genus, tests for gene exchange based on phylogenetic incongruence may be susceptible to false positives. PMID:26559010

  17. Disrupting Protein Expression with Peptide Nucleic Acids Reduces Infection by Obligate Intracellular Rickettsia

    PubMed Central

    Pelc, Rebecca S.; McClure, Jennifer C.; Kaur, Simran J.; Sears, Khandra T.; Rahman, M. Sayeedur; Ceraul, Shane M.

    2015-01-01

    Peptide Nucleic Acids (PNAs) are single-stranded synthetic nucleic acids with a pseudopeptide backbone in lieu of the phosphodiester linked sugar and phosphate found in traditional oligos. PNA designed complementary to the bacterial Shine-Dalgarno or start codon regions of mRNA disrupts translation resulting in the transient reduction in protein expression. This study examines the use of PNA technology to interrupt protein expression in obligate intracellular Rickettsia sp. Their historically intractable genetic system limits characterization of protein function. We designed PNA targeting mRNA for rOmpB from Rickettsia typhi and rickA from Rickettsia montanensis, ubiquitous factors important for infection. Using an in vitro translation system and competitive binding assays, we determined that our PNAs bind target regions. Electroporation of R. typhi and R. montanensis with PNA specific to rOmpB and rickA, respectively, reduced the bacteria’s ability to infect host cells. These studies open the possibility of using PNA to suppress protein synthesis in obligate intracellular bacteria. PMID:25781160

  18. Arsenophonus nasoniae and Rickettsiae Infection of Ixodes ricinus Due to Parasitic Wasp Ixodiphagus hookeri

    PubMed Central

    Bohacsova, Monika; Mediannikov, Oleg; Kazimirova, Maria; Raoult, Didier; Sekeyova, Zuzana

    2016-01-01

    Arsenophonus nasoniae, a male-killing endosymbiont of chalcid wasps, was recently detected in several hard tick species. Following the hypothesis that its presence in ticks may not be linked to the direct occurrence of bacteria in tick's organs, we identified A. nasoniae in wasps emerging from parasitised nymphs. We confirmed that 28.1% of Ixodiphagus hookeri wasps parasitizing Ixodes ricinus ticks were infected by A. nasoniae. Moreover, in examined I. ricinus nymphs, A. nasoniae was detected only in those, which were parasitized by the wasp. However, in part of the adult wasps as well as in some ticks that contained wasp's DNA, we did not confirm A. nasoniae. We also found, that in spite of reported male-killing, some newly emerged adult wasp males were also infected by A. nasoniae. Additionally, we amplified the DNA of Rickettsia helvetica and Rickettsia monacensis (known to be Ixodes ricinus-associated bacteria) in adult parasitoid wasps. This may be related either with the digested bacterial DNA in wasp body lumen or with a role of wasps in circulation of rickettsiae among tick vectors. PMID:26901622

  19. Emerging Tick-borne Rickettsia and Ehrlichia at Joint Base Langley-Eustis, Fort Eustis, Virginia.

    PubMed

    Miller, Melissa K; Jiang, Ju; Truong, Melissa; Yarina, Tamasin; Evans, Holly; Christensen, Timothy P; Richards, Allen L

    2016-01-01

    Four species of ticks known to parasitize humans (Amblyomma americanum (lone star tick), Dermacentor variabilis (American dog tick), Amblyomma maculatum (Gulf Coast tick), and Ixodes scapularis (black-legged tick)) were collected at Joint Base Langley-Eustis, Fort Eustis, Virginia during 2009. These ticks were tested individually (adults and nymphs) and in pools of 15 (larvae) for pathogens of public health importance within the genera: Rickettsia, Borrelia, and Ehrlichia, by quantitative real-time polymerase chain reaction (qPCR) assays and, where appropriate, multilocus sequence typing (MLST). Of the 340 A americanum ticks tested, a minimum of 65 (19%), 4 (1%), 4 (1%), and one (<1%) were positive for Rickettsia amblyommii, B lonestari, E ewingii and E chaffeensis, respectively. One of 2 (50%) A maculatum ticks collected was found to be positive for R parkeri by MLST and qPCR analyses. All 33 D variabilis ticks were negative for evidence of rickettsial infections. Likewise, no pathogenic organisms were detected from the single Ixodes scapularis tick collected. Pathogenic rickettsiae and ehrlichiae are likely emerging and cause under-recognized diseases, which threaten people who live, work, train, or otherwise engage in outdoor activities at, or in the vicinity of, Fort Eustis, Virginia. PMID:27613206

  20. Arsenophonus nasoniae and Rickettsiae Infection of Ixodes ricinus Due to Parasitic Wasp Ixodiphagus hookeri.

    PubMed

    Bohacsova, Monika; Mediannikov, Oleg; Kazimirova, Maria; Raoult, Didier; Sekeyova, Zuzana

    2016-01-01

    Arsenophonus nasoniae, a male-killing endosymbiont of chalcid wasps, was recently detected in several hard tick species. Following the hypothesis that its presence in ticks may not be linked to the direct occurrence of bacteria in tick's organs, we identified A. nasoniae in wasps emerging from parasitised nymphs. We confirmed that 28.1% of Ixodiphagus hookeri wasps parasitizing Ixodes ricinus ticks were infected by A. nasoniae. Moreover, in examined I. ricinus nymphs, A. nasoniae was detected only in those, which were parasitized by the wasp. However, in part of the adult wasps as well as in some ticks that contained wasp's DNA, we did not confirm A. nasoniae. We also found, that in spite of reported male-killing, some newly emerged adult wasp males were also infected by A. nasoniae. Additionally, we amplified the DNA of Rickettsia helvetica and Rickettsia monacensis (known to be Ixodes ricinus-associated bacteria) in adult parasitoid wasps. This may be related either with the digested bacterial DNA in wasp body lumen or with a role of wasps in circulation of rickettsiae among tick vectors. PMID:26901622

  1. Isolation and identification of Rickettsia massiliae from Rhipicephalus sanguineus ticks collected in Arizona.

    PubMed

    Eremeeva, Marina E; Bosserman, Elizabeth A; Demma, Linda J; Zambrano, Maria L; Blau, Dianna M; Dasch, Gregory A

    2006-08-01

    Twenty Rhipicephalus sanguineus ticks collected in eastern Arizona were tested by PCR assay to establish their infection rate with spotted fever group rickettsiae. With a nested PCR assay which detects a fragment of the Rickettsia genus-specific 17-kDa antigen gene (htrA), five ticks (25%) were found to contain rickettsial DNA. One rickettsial isolate was obtained from these ticks by inoculating a suspension of a triturated tick into monolayers of Vero E6 monkey kidney cells and XTC-2 clawed toad cells, and its cell culture and genotypic characteristics were determined. Fragments of the 16S rRNA, GltA, rOmpA, rOmpB, and Sca4 genes had 100%, 100%, 99%, 99%, and 99%, respectively, nucleotide similarity to Rickettsia massiliae strain Bar29, previously isolated from R. sanguineus in Catalonia, Spain (L. Beati et al., J. Clin. Microbiol. 34:2688-2694, 1996). The new isolate, AZT80, does not elicit cytotoxic effects in Vero cells and causes a persistent infection in XTC-2 cells. The AZT80 strain is susceptible to doxycycline but resistant to rifampin and erythromycin. Whether R. massiliae AZT80 is pathogenic or infectious for dogs and humans or can cause seroconversion to spotted fever group antigens in the United States is unknown. PMID:16885311

  2. The Phylogeny of Rickettsia Using Different Evolutionary Signatures: How Tree-Like is Bacterial Evolution?

    PubMed

    Murray, Gemma G R; Weinert, Lucy A; Rhule, Emma L; Welch, John J

    2016-03-01

    Rickettsia is a genus of intracellular bacteria whose hosts and transmission strategies are both impressively diverse, and this is reflected in a highly dynamic genome. Some previous studies have described the evolutionary history of Rickettsia as non-tree-like, due to incongruity between phylogenetic reconstructions using different portions of the genome. Here, we reconstruct the Rickettsia phylogeny using whole-genome data, including two new genomes from previously unsampled host groups. We find that a single topology, which is supported by multiple sources of phylogenetic signal, well describes the evolutionary history of the core genome. We do observe extensive incongruence between individual gene trees, but analyses of simulations over a single topology and interspersed partitions of sites show that this is more plausibly attributed to systematic error than to horizontal gene transfer. Some conflicting placements also result from phylogenetic analyses of accessory genome content (i.e., gene presence/absence), but we argue that these are also due to systematic error, stemming from convergent genome reduction, which cannot be accommodated by existing phylogenetic methods. Our results show that, even within a single genus, tests for gene exchange based on phylogenetic incongruence may be susceptible to false positives. PMID:26559010

  3. Structural properties of lipopolysaccharides from Rickettsia typhi and Rickettsia prowazekii and their chemical similarity to the lipopolysaccharide from Proteus vulgaris OX19 used in the Weil-Felix test.

    PubMed

    Amano, K I; Williams, J C; Dasch, G A

    1998-03-01

    The lipopolysaccharides (LPSs) isolated from typhus group (TG) rickettsiae Rickettsia typhi and Rickettsia prowazekii were characterized by chemical analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by silver staining. LPSs from two species of TG rickettsiae contained glucose, 3-deoxy-D-manno-octulosonic acid, glucosamine, quinovosamine, phosphate, and fatty acids (beta-hydroxylmyristic acid and heneicosanoic acid) but not heptose. The O-polysaccharides of these LPSs were composed of glucose, glucosamine, quinovosamine, and phosphorylated hexosamine. Resolution of these LPSs by their apparent molecular masses by SDS-PAGE showed that they have a common ladder-like pattern. Based on the results of chemical composition and SDS-PAGE pattern, we suggest that these LPSs act as group-specific antigens. Furthermore, glucosamine, quinovosamine, and phosphorylated hexosamine were also found in the O-polysaccharide of the LPS from Proteus vulgaris OX19 used in the Weil-Felix test, suggesting that they may represent the antigens common to LPSs from TG rickettsiae and P. vulgaris OX19. PMID:9488376

  4. Implication of the Bacterial Endosymbiont Rickettsia spp. in Interactions of the Whitefly Bemisia tabaci with Tomato yellow leaf curl virus

    PubMed Central

    Kliot, Adi; Cilia, Michelle; Czosnek, Henryk

    2014-01-01

    ABSTRACT Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. We report here that infection with Rickettsia spp., a facultative endosymbiont of whiteflies, altered TYLCV-B. tabaci interactions. A B. tabaci strain infected with Rickettsia acquired more TYLCV from infected plants, retained the virus longer, and exhibited nearly double the transmission efficiency compared to an uninfected B. tabaci strain with the same genetic background. Temporal and spatial antagonistic relationships were discovered between Rickettsia and TYLCV within the whitefly. In different time course experiments, the levels of virus and Rickettsia within the insect were inversely correlated. Fluorescence in situ hybridization analysis of Rickettsia-infected midguts provided evidence for niche exclusion between Rickettsia and TYLCV. In particular, high levels of the bacterium in the midgut resulted in higher virus concentrations in the filter chamber, a favored site for virus translocation along the transmission pathway, whereas low levels of Rickettsia in the midgut resulted in an even distribution of the virus. Taken together, these results indicate that Rickettsia, by infecting the midgut, increases TYLCV transmission efficacy, adding further insights into the complex association between persistent plant viruses, their insect vectors, and microorganism tenants that reside within these insects. IMPORTANCE Interest in bacterial endosymbionts in arthropods and many aspects of their host biology in agricultural and human health systems has been increasing. A recent and relevant studied example is the influence of Wolbachia on dengue virus transmission by mosquitoes. In parallel with our recently studied whitefly-Rickettsia-TYLCV system, other studies have shown that dengue virus levels in the mosquito vector are inversely correlated with

  5. Molecular detection of spotted fever group rickettsia in feral raccoons (Procyon lotor) in the western part of Japan.

    PubMed

    Baba, Kenji; Kaneda, Toshiya; Nishimura, Hitoshi; Sato, Hiroshi

    2013-02-01

    Rickettsial infection in feral raccoons (Procyon lotor) in the western part of Japan (Shimane, Fukuoka, Saga and Nagasaki Prefectures) was surveyed by a nested polymerase chain reaction (PCR) assay detecting the rickettsial citrate synthase (gltA) gene. Four of one hundred and ninety-four feral raccoon spleens (2.1%) were positive for Rickettsia spp. One gltA gene sequence was identical to R. helvetica, whereas the other 3 sequences were identical and had the highest similarity (98.4%) to R. amblyommii. Simultaneously, we determined a partial sequence of the rickettsial 17-kilodalton (17K) genus-common antigen gene in the later 3 raccoon samples. Their sequences were identical and had the highest similarity (98.5%) to Rickettsia sp. Hj126. Based on the sequences of gltA and 17K antigen genes, these raccoons might be infected with spotted fever group (SFG) rickettsia most closely related to R. amblyommii and/or Rickettsia sp. Hj126. Feral raccoons may be a susceptible reservoir for SFG rickettsiae in Japan. PMID:22986299

  6. Absence of serological evidence of Rickettsia spp., Bartonella spp., Ehrlichia spp. and Coxiella burnetii infections in American Samoa.

    PubMed

    Lau, Colleen; Musso, Didier; Fournier, Pierre-Edouard; Parola, Philippe; Raoult, Didier; Weinstein, Philip

    2016-07-01

    Little is known about the epidemiology of zoonotic diseases in American Samoa (Pacific). A review of literature did not identify any published information on human Rickettsia spp., Bartonella spp., Ehrlichia spp. or Coxiella burnetii infections in this country. To determine the presence of these diseases, we conducted a serosurvey of American Samoans. The presence of immunoglobulin G antibodies against Rickettsia felis, Rickettsia typhi, Rickettsia conorii, C. burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis was evaluated by indirect immunofluorescence assay in sera from 197 American Samoan adults. None of the samples had antibodies at a significant level against Rickettsia spp., Bartonella spp., Ehrlichia spp. or C. burnetii (seroprevalence 0%; one-tailed 95% CI 0-1.86%). We cannot conclude that these pathogens are absent in American Samoa but, if present, their prevalence is probably very low. Q fever has been reported worldwide except in New Zealand and French Polynesia; these new data suggest that the prevalence of Q fever is likely to be very low in the Pacific Islands. PMID:26965788

  7. Rickettsia ‘In’ and ‘Out’: Two Different Localization Patterns of a Bacterial Symbiont in the Same Insect Species

    PubMed Central

    Caspi-Fluger, Ayelet; Inbar, Moshe; Mozes-Daube, Netta; Mouton, Laurence; Hunter, Martha S.; Zchori-Fein, Einat

    2011-01-01

    Intracellular symbionts of arthropods have diverse influences on their hosts, and their functions generally appear to be associated with their localization within the host. The effect of localization pattern on the role of a particular symbiont cannot normally be tested since the localization pattern within hosts is generally invariant. However, in Israel, the secondary symbiont Rickettsia is unusual in that it presents two distinct localization patterns throughout development and adulthood in its whitefly host, Bemisia tabaci (B biotype). In the “scattered” pattern, Rickettsia is localized throughout the whitefly hemocoel, excluding the bacteriocytes, where the obligate symbiont Portiera aleyrodidarum and some other secondary symbionts are housed. In the “confined” pattern, Rickettsia is restricted to the bacteriocytes. We examined the effects of these patterns on Rickettsia densities, association with other symbionts (Portiera and Hamiltonella defensa inside the bacteriocytes) and on the potential for horizontal transmission to the parasitoid wasp, Eretmocerus mundus, while the wasp larvae are developing within the whitefly nymph. Sequences of four Rickettsia genes were found to be identical for both localization patterns, suggesting that they are closely related strains. However, real-time PCR analysis showed very different dynamics for the two localization types. On the first day post-adult emergence, Rickettsia densities were 21 times higher in the “confined” pattern vs. “scattered” pattern whiteflies. During adulthood, Rickettsia increased in density in the “scattered” pattern whiteflies until it reached the “confined” pattern Rickettsia density on day 21. No correlation between Rickettsia densities and Hamiltonella or Portiera densities were found for either localization pattern. Using FISH technique, we found Rickettsia in the gut of the parasitoid wasps only when they developed on whiteflies with the “scattered” pattern. The

  8. High Prevalence of Rickettsia typhi and Bartonella Species in Rats and Fleas, Kisangani, Democratic Republic of the Congo

    PubMed Central

    Laudisoit, Anne; Falay, Dadi; Amundala, Nicaise; Akaibe, Dudu; de Bellocq, Joëlle Goüy; Van Houtte, Natalie; Breno, Matteo; Verheyen, Erik; Wilschut, Liesbeth; Parola, Philippe; Raoult, Didier; Socolovschi, Cristina

    2014-01-01

    The prevalence and identity of Rickettsia and Bartonella in urban rat and flea populations were evaluated in Kisangani, Democratic Republic of the Congo (DRC) by molecular tools. An overall prevalence of 17% Bartonella species and 13% Rickettsia typhi, the agent of murine typhus, was found in the cosmopolitan rat species, Rattus rattus and Rattus norvegicus that were infested by a majority of Xenopsylla cheopis fleas. Bartonella queenslandensis, Bartonella elizabethae, and three Bartonella genotypes were identified by sequencing in rat specimens, mostly in R. rattus. Rickettsia typhi was detected in 72% of X. cheopis pools, the main vector and reservoir of this zoonotic pathogen. Co-infections were observed in rodents, suggesting a common mammalian host shared by R. typhi and Bartonella spp. Thus, both infections are endemic in DRC and the medical staffs need to be aware knowing the high prevalence of impoverished populations or immunocompromised inhabitants in this area. PMID:24445202

  9. Rickettsiae in arthropods collected from the North African Hedgehog (Atelerix algirus) and the desert hedgehog (Paraechinus aethiopicus) in Algeria.

    PubMed

    Khaldi, Mourad; Socolovschi, Cristina; Benyettou, Meryam; Barech, Ghania; Biche, Mohamed; Kernif, Tahar; Raoult, Didier; Parola, Philippe

    2012-03-01

    Hedgehogs have become a popular pet despite their potential role in zoonotic disease transmission. We conducted an entomological study in a mountainous region of northeast Algeria in which we collected 387 fleas (Archeopsylla erinacei) and 342 ticks (Rhipicephalus sanguineus and Haemaphysalis erinacei) from Paraechinus aethiopicus and Atelerix algirus hedgehogs. Of the hedgehogs sampled, 77.7% and 91% were infested with fleas and ticks, respectively. Significantly more ticks and fleas were collected from A. algirus than from P. aethiopicus. Rickettsia felis was detected in 95.5% of fleas and R. massiliae was detected in 6.25% of Rh. sanguineus ticks by molecular tools. A new Rickettsia species of the spotted fever group was detected in 11.25% of Rh. sanguineus and in 77% of H. erinacei ticks. Overall, we show that hedgehogs can act as hosts for ectoparasites infected with several rickettsial agents. These data justify a more detailed investigation of animal reservoirs for Rickettsiae. PMID:22222114

  10. Rickettsia sp. Strain Atlantic Rainforest Infection in a Patient from a Spotted Fever-Endemic Area in Southern Brazil.

    PubMed

    Krawczak, Felipe S; Muñoz-Leal, Sebastián; Guztzazky, Ana Carolina; Oliveira, Stefan V; Santos, Fabiana C P; Angerami, Rodrigo N; Moraes-Filho, Jonas; de Souza, Julio C; Labruna, Marcelo B

    2016-09-01

    Santa Catarina State in southern Brazil is the state with the second highest number of laboratory-confirmed cases of spotted fever illness in Brazil. However, all these cases were confirmed solely by serological analysis (seroconversion to spotted fever group rickettsiae), which has not allowed identification of the rickettsial agent. Here, a clinical case of spotted fever illness from Santa Catarina is shown by seroconversion and molecular analysis to be caused by Rickettsia sp. strain Atlantic rainforest. This is the third confirmed clinical case due to this emerging rickettsial agent in Brazil. Like the previous two cases, the patient presented an inoculation eschar at the tick bite site. Our molecular diagnosis was performed on DNA extracted from the crust removed from the eschar. These results are supported by previous epidemiological studies in Santa Catarina, which showed that nearly 10% of the most common human-biting ticks were infected by Rickettsia sp. strain Atlantic rainforest. PMID:27325804

  11. Rickettsia rickettsii isolation from naturally infected Amblyomma parvum ticks by centrifugation in a 24-well culture plate technique

    PubMed Central

    Dzul-Rosado, K.; Peniche-Lara, G.; Tello-Martín, R.; Zavala-Velázquez, J.; Pacheco, R. de Campos; Labruna, M.B.; Sánchez, E.C.; Zavala-Castro, J.

    2013-01-01

    Rocky Mountain spotted fever is an acute illness caused by Rickettsia rickettsii (R. rickettsii) and is transmitted by the bite of ticks of the genera Dermacentor, Amblyomma and Rhipicephalus. The illness results in a high mortality rate and may be easily confused with other febrile syndromes. In Yucatan State, Mexico, childhood cases with a high mortality have been reported. In this work we report the isolation of a Mexican R. rickettsii strain from a tick egg mass using an alternative method for Rickettsia isolation with 24-well plates. We also identified a potential vector of R. rickettsii in the southeast of Mexico, which is Amblyomma parvum. PMID:26623321

  12. Detection of Borrelia burgdorferi sensu lato and spotted fever group rickettsiae in hard ticks (Acari, Ixodidae) parasitizing bats in Poland.

    PubMed

    Piksa, Krzysztof; Stańczak, Joanna; Biernat, Beata; Górz, Andrzej; Nowak-Chmura, Magdalena; Siuda, Krzysztof

    2016-04-01

    A total of 491 Ixodes vespertilionis and 8 Ixodes ricinus collected from bats and cave walls in southern Poland between 2010 and 2012 were examined by the polymerase chain reaction for tick-transmitted pathogens. PCR analysis for Borrelia burgdorferi s.l., Rickettsia spp., and Anaplasma phagocytophilum yielded negative results for all I. vespertilionis. DNA of Rickettsia helvetica was detected in three specimens of I. ricinus attached to Rhinolophus hipposideros or Myotis myotis, while Borrelia garinii was found in one tick parasitizing Myotis daubentonii. These pathogens were recorded for the first time in hard ticks that parasitized bats. PMID:26833325

  13. Two Bacterial Genera, Sodalis and Rickettsia, Associated with the Seal Louse Proechinophthirus fluctus (Phthiraptera: Anoplura)

    PubMed Central

    Allen, Julie M.; Koga, Ryuichi; Fukatsu, Takema; Sweet, Andrew D.; Johnson, Kevin P.; Reed, David L.

    2016-01-01

    ABSTRACT Roughly 10% to 15% of insect species host heritable symbiotic bacteria known as endosymbionts. The lice parasitizing mammals rely on endosymbionts to provide essential vitamins absent in their blood meals. Here, we describe two bacterial associates from a louse, Proechinophthirus fluctus, which is an obligate ectoparasite of a marine mammal. One of these is a heritable endosymbiont that is not closely related to endosymbionts of other mammalian lice. Rather, it is more closely related to endosymbionts of the genus Sodalis associated with spittlebugs and feather-chewing bird lice. Localization and vertical transmission of this endosymbiont are also more similar to those of bird lice than to those of other mammalian lice. The endosymbiont genome appears to be degrading in symbiosis; however, it is considerably larger than the genomes of other mammalian louse endosymbionts. These patterns suggest the possibility that this Sodalis endosymbiont might be recently acquired, replacing a now-extinct, ancient endosymbiont. From the same lice, we also identified an abundant bacterium belonging to the genus Rickettsia that is closely related to Rickettsia ricketsii, a human pathogen vectored by ticks. No obvious masses of the Rickettsia bacterium were observed in louse tissues, nor did we find any evidence of vertical transmission, so the nature of its association remains unclear. IMPORTANCE Many insects are host to heritable symbiotic bacteria. These heritable bacteria have been identified from numerous species of parasitic lice. It appears that novel symbioses have formed between lice and bacteria many times, with new bacterial symbionts potentially replacing existing ones. However, little was known about the symbionts of lice parasitizing marine mammals. Here, we identified a heritable bacterial symbiont in lice parasitizing northern fur seals. This bacterial symbiont appears to have been recently acquired by the lice. The findings reported here provide insights

  14. Rickettsia amblyommii infecting Amblyomma auricularium ticks in Pernambuco, northeastern Brazil: isolation, transovarial transmission, and transstadial perpetuation.

    PubMed

    Saraiva, Danilo G; Nieri-Bastos, Fernanda A; Horta, Maurício C; Soares, Herbert S; Nicola, Patricia A; Pereira, Luiz Cezar M; Labruna, Marcelo B

    2013-09-01

    This study investigated rickettsial infection in Amblyomma auricularium ticks from the state of Pernambuco, northeastern Brazil. An engorged female of A. auricularium collected from a skunk (Conepatus semistriatus) was sent alive to the laboratory, where the female was found through molecular analysis to be infected by Rickettsia amblyommii. This engorged female oviposited, and its offspring was reared through three consecutive generations, always using tick-naïve rabbits to feed the ticks. PCR performed on five egg pools, 10 larvae, 10 nymphs, and 10 adults of each of the three generations always yielded rickettsial DNA, indicating maintenance of rickettsial infection in the ticks by transstadial and transovarial passages. DNA sequences of random PCR products from eggs, larvae, nymphs, and adults were identified as R. amblyommii. All infested rabbits seroconverted to R. amblyommii antigens at the 21(st) day after infestation, indicating that larvae, nymphs, and adults transmitted R. amblyommii through parasitism. However, no infested rabbit presented fever or any clinical alteration during the experimental period. Rickettsiae were successfully isolated from the two A. auricularium females, and the isolates were established in Vero cell culture. Molecular characterization of the isolates confirmed R. amblyommii by sequencing partial gltA, ompA, and ompB genes. From another sample of 15 A. auricularium adult ticks collected from two armadillos (Euphractus sexcinctus), eight (53.3%) were infected by R. amblyommii. This study reports R. amblyommii infecting the tick A. auricularium for the first time. This is also the first report of rickettsia infecting ticks in the northeastern region of Brazil. PMID:23705586

  15. Notes from the Field: Rickettsia parkeri Rickettsiosis - Georgia, 2012-2014.

    PubMed

    Straily, Anne; Feldpausch, Amanda; Ulbrich, Carl; Schell, Kiersten; Casillas, Shannon; Zaki, Sherif R; Denison, Amy M; Condit, Marah; Gabel, Julie; Paddock, Christopher D

    2016-01-01

    During 2012-2014, five cases of Rickettsia parkeri rickettsiosis were identified by a single urgent care practice in Georgia, located approximately 40 miles southwest of Atlanta. Symptom onset occurred during June-October, and all patients had a known tick bite. Patients ranged in age from 27 to 72 years (median = 53 years), and all were male. The most commonly reported initial signs were erythema (n = 3) and swelling (n = 2) at the site of the bite. Two patients reported fever and a third patient reported a rash and lymphadenopathy without fever. Other symptoms included myalgia (n = 3), chills (n = 3), fatigue (n = 2), arthralgia (n = 2), and headache (n = 2). Eschar biopsy specimens were collected from each patient using a 4-mm or 5-mm punch and placed in 10% neutral buffered formalin or sterile saline. These specimens were tested by immunohistochemical (IHC) stains, quantitative polymerase chain reaction (qPCR) assays, or cell culture isolation to determine if there was evidence of infection with a Rickettsia species (1). IHC evidence of spotted fever group rickettsiae was found in the eschar biopsy specimens in all five cases. In four cases, the biopsy specimens were also positive for R. parkeri by qPCR. The fifth case (specimen positive only by IHC testing) was considered a probable R. parkeri case based on clinical signs and symptoms. R. parkeri was grown in cell culture from one specimen from which isolation was attempted. All patients were treated with oral doxycycline (100 mg twice daily) for a minimum of 10 days, and all recovered. PMID:27442517

  16. Detection of Borrelia, Ehrlichia, and Rickettsia spp. in ticks in northeast Missouri.

    PubMed

    Hudman, D A; Sargentini, N J

    2016-07-01

    We evaluated Amblyomma americanum (lone star tick) and Dermacentor variabilis (American dog tick) in northeast Missouri for the presence of Borrelia, Ehrlichia, and Rickettsia bacteria. We collected actively questing ticks from four sites within Adair County, Missouri. A total of 15,162 ticks were collected, of which 13,980 were grouped in 308 pools (lone star ticks, 288 pools; American dog ticks, 20 pools) and tested for presence/absence of bacteria using polymerase chain reaction. Infection rates were calculated as the maximum likelihood estimation (MLE) with 95% confidence intervals (CI). Of the 308 pools tested, 229 (74.4%) were infected with bacteria and the overall MLE of the infection rate per 100 ticks was calculated as 2.9% (CI 2.61-3.21). Infection rates varied among life stages, 28.6% (CI 23.89-33.97) in adults, 7.0% (CI 5.10-9.86) in nymphs, and 1.0% (CI 0.75-1.20) in larvae. In the 116 adult lone star pools, infection rates were calculated for Borrelia lonestari (1.4%), Borrelia spp. (2.7%), Ehrlichia chaffeensis (6.1%), Ehrlichia ewingii (3.3%), Rickettsia amblyommii (18.3%), and Rickettsia montanensis (0.4%). Infection rates for the 52 nymphal lone star pools were calculated as B. lonestari (1.03%), Borrelia spp. (0.40%), E. chaffeensis (2.02%), E. ewingii (0.24%), and R. amblyommii (2.70%). In the 20 adult American dog tick pools, infection rates were determined as E. chaffeensis (9.47%), E. ewingii (5.47%), and R. montanensis (8.06%). Eight Borrelia samples were sequenced with five 99-100% identical to B. burgdorferi (s.l.) and three 99% identical to B. lonestari. Eight samples were sequenced for E. chaffeensis (all 99-100% identical) and one sample was sequenced for E. ewingii (99% identical). Seven samples were sequenced for Rickettsia and three were 99% identical to R. montanensis and four were 100% identical to R. amblyommii. This study demonstrates B. lonestari, E. chaffeensis, E. ewingii, R. amblyommii, and R. montanensis in northeast

  17. Bartonella and Rickettsia in arthropods from the Lao PDR and from Borneo, Malaysia☆

    PubMed Central

    Kernif, Tahar; Socolovschi, Cristina; Wells, Konstans; Lakim, Maklarin B.; Inthalad, Saythong; Slesak, Günther; Boudebouch, Najma; Beaucournu, Jean-Claude; Newton, Paul N.; Raoult, Didier; Parola, Philippe

    2012-01-01

    Rickettsioses and bartonelloses are arthropod-borne diseases of mammals with widespread geographical distributions. Yet their occurrence in specific regions, their association with different vectors and hosts and the infection rate of arthropod-vectors with these agents remain poorly studied in South-east Asia. We conducted entomological field surveys in the Lao PDR (Laos) and Borneo, Malaysia by surveying fleas, ticks, and lice from domestic dogs and collected additional samples from domestic cows and pigs in Laos. Rickettsia felis was detected by real-time PCR with similar overall flea infection rate in Laos (76.6%, 69/90) and Borneo (74.4%, 268/360). Both of the encountered flea vectors Ctenocephalides orientis and Ctenocephalides felis felis were infected with R. felis. The degrees of similarity of partial gltA and ompA genes with recognized species indicate the rickettsia detected in two Boophilus spp. ticks collected from a cow in Laos may be a new species. Isolation and further characterization will be necessary to specify it as a new species. Bartonella clarridgeiae was detected in 3/90 (3.3%) and 2/360 (0.6%) of examined fleas from Laos and Borneo, respectively. Two fleas collected in Laos and one flea collected in Borneo were co-infected with both R. felis and B. clarridgeiae. Further investigations are needed in order to isolate these agents and to determine their epidemiology and aetiological role in unknown fever in patients from these areas. PMID:22153360

  18. Proteome Analysis and Serological Characterization of Surface-Exposed Proteins of Rickettsia heilongjiangensis

    PubMed Central

    Qi, Yong; Xiong, Xiaolu; Wang, Xile; Duan, Changsong; Jia, Yinjun; Jiao, Jun; Gong, Wenping; Wen, Bohai

    2013-01-01

    Background Rickettsia heilongjiangensis, the agent of Far-Eastern spotted fever (FESF), is an obligate intracellular bacterium. The surface-exposed proteins (SEPs) of rickettsiae are involved in rickettsial adherence to and invasion of host cells, intracellular bacterial growth, and/or interaction with immune cells. They are also potential molecular candidates for the development of diagnostic reagents and vaccines against rickettsiosis. Methods R. heilongjiangensis SEPs were identified by biotin-streptavidin affinity purification and 2D electrophoreses coupled with ESI-MS/MS. Recombinant SEPs were probed with various sera to analyze their serological characteristics using a protein microarray and an enzyme-linked immune sorbent assay (ELISA). Results Twenty-five SEPs were identified, most of which were predicted to reside on the surface of R. heilongjiangensis cells. Bioinformatics analysis suggests that these proteins could be involved in bacterial pathogenesis. Eleven of the 25 SEPs were recognized as major seroreactive antigens by sera from R. heilongjiangensis-infected mice and FESF patients. Among the major seroreactive SEPs, microarray assays and/or ELISAs revealed that GroEL, OmpA-2, OmpB-3, PrsA, RplY, RpsB, SurA and YbgF had modest sensitivity and specificity for recognizing R. heilongjiangensis infection and/or spotted fever. Conclusions Many of the SEPs identified herein have potentially important roles in R. heilongjiangensis pathogenicity. Some of them have potential as serodiagnostic antigens or as subunit vaccine antigens against the disease. PMID:23894656

  19. Growth of Rickettsia typhi in irradiated L cells enhanced by lysosomal stabilization.

    PubMed Central

    Woodman, D R; Schultz, W W; Woodman, K L; Weiss, E

    1979-01-01

    The growth of some obligate intracellular parasites is contingent upon avoidance of lysosomal activation during growth in their host cells. This is accomplished by the various parasites by different mechanisms and with different degrees of efficiency. The possibility was tested that the lysosomal stabilizer cortisone acetate might protect and thus enhance the growth of Rickettsia typhi in mouse L cells irradiated 6 days earlier. Beginning 2 days before infection of the L cells with a multiplicity of 10 rickettsiae, 20 microgram of cortisone per ml was added in medium 199 containing 5% fetal calf serum. This concentration of cortisone was below the cytotoxic level, as determined by viability staining, but was sufficient to significantly alter the ratios of cellular and released acid phosphatase and beta-glucuronidase in uninfected and infected cells, as shown by spectrophotometric analysis. Rickettsial replication, measured by hemolytic activity at 96 h and confirmed by microscopic observations at earlier stages of infection, was increased by the cortisone. Cortisone concentrations of 10 or 40 microgram/ml were less effective, and cortisone was ineffective when the rickettsial multiplicity per L cell was 2 or lower. These results indicate that amounts of cortisone that increase lysosomal stabilization in L cells favor rickettsial multiplication when the multiplicity of infection is relatively high. PMID:106007

  20. Seroprevalence of antibodies to Rickettsia typhi in the Waikato region of New Zealand.

    PubMed

    Lim, M Y; Weinstein, P; Bell, A; Hambling, T; Tompkins, D M; Slaney, D

    2016-08-01

    The first reported New Zealand-acquired case of murine typhus occurred near Auckland in 1989. Since then, 72 locally acquired cases have been recorded from northern New Zealand. By 2008, on the basis of the timing and distribution of cases, it appeared that murine typhus was escalating and spreading southwards. To explore the presence of Rickettsia typhi in the Waikato region, we conducted a seroprevalence study, using indirect immunofluorescence, Western blot, and cross-adsorption assays of blood donor samples. Of 950 human sera from Waikato, 12 (1·3%) had R. typhi antibodies. The seroprevalence for R. typhi was slightly higher in northern Waikato (1·4%) compared to the south (1·2%; no significant difference, χ 2 P = 0·768 at P < 0·05). Our results extend the reported southern range of R. typhi by 140 km and indicate it is endemic in Waikato. Evidence of past Rickettsia felis infections was also detected in six sera. Globally, R. felis is an emerging disease of concern and this pathogen should also be considered when locally acquired rickettsiosis is suspected. If public health interventions are to be implemented to reduce the risk of rickettsioses as a significant public health problem, improvements in rickettsial diagnostics and surveillance will be necessary. PMID:27040715

  1. Detection of a novel Rickettsia sp. in soft ticks (Acari: Argasidae) in Algeria.

    PubMed

    Lafri, Ismail; Leulmi, Hamza; Baziz-Neffah, Fadhila; Lalout, Reda; Mohamed, Chergui; Mohamed, Karakallah; Parola, Philippe; Bitam, Idir

    2015-01-01

    Argasid ticks are vectors of viral and bacterial agents that can infect humans and animals. In Africa, relapsing fever borreliae are neglected arthropod-borne pathogens that cause mild to deadly septicemia and miscarriage. It would be incredibly beneficial to be able to simultaneous detect and identify other pathogens transmitted by Argasid ticks. From 2012 to 2014, we conducted field surveys in 4 distinct areas of Algeria. We investigated the occurrence of soft ticks in rodent burrows and yellow-legged gull (Larus michahellis) nests in 10 study sites and collected 154 soft ticks. Molecular identification revealed the occurrence of two different soft tick genera and five species, including Carios capensis in yellow-legged gull nests and Ornithodoros occidentalis, Ornithodoros rupestris, Ornithodoros sonrai, Ornithodoros erraticus in rodent burrows. Rickettsial DNA was detected in 41/154, corresponding to a global detection rate of 26.6%. Sequences of the citrate synthase (gltA) gene suggest that this agent is a novel spotted fever group Rickettsia. For the first time in Algeria, we characterize a novel Rickettsia species by molecular means in soft ticks. PMID:26408401

  2. A cluster of Rickettsia rickettsii infection at an animal shelter in an urban area of Brazil.

    PubMed

    Rozental, T; Ferreira, M S; Gomes, R; Costa, C M; Barbosa, P R A; Bezerra, I O; Garcia, M H O; Oliveira E Cruz, D M; Galliez, R; Oliveira, S; Brasil, P; Rezende, T; De Lemos, E R S

    2015-08-01

    Rickettsia rickettsii infection is being increasingly recognized as an important cause of fatal acute illness in Brazil, where this tick-borne disease is designated Brazilian spotted fever (BSF). In this study we report five fatal cases of BSF in employees of an animal shelter in an urban area in the municipality of Rio de Janeiro in southeast Brazil after a natural disaster on 11 January 2011. Four of the cases occurred from 27 January to 11 April 2011, while the fifth fatal case was identified in April 2012. Three cases were confirmed by molecular analysis and two by epidemiological linkage. An investigation of BSF was performed in the animal shelter, and blood samples were collected from 115 employees and 117 randomly selected dogs. The presence of high levels (1024-4096) of antibodies against spotted fever group rickettsiae was found in three (2·6%) employees and 114 (97·5%) dogs. These findings emphasize the need to consider BSF as a possible cause of undifferentiated febrile illness, especially dengue and leptospirosis, in patients occupationally exposed to dogs heavily infested by ticks, mainly working at kennels and animal shelters that have inadequate space for the animals housed and frequently providing an environment conducive to exposure to pathogens such as R. rickettsii. PMID:25483025

  3. Serological evidence of Rickettsia and Coxiella burnetii in humans of Buenos Aires, Argentina.

    PubMed

    Cicuttin, Gabriel Leonardo; Degiuseppe, Juan Ignacio; Mamianetti, Andrea; Corin, Marcela Viviana; Linares, María Cielo; De Salvo, María Nazarena; Dohmen, Federico Eugenio Gury

    2015-12-01

    In Buenos Aires city (Argentina), the circulation of these agents has been detected mainly in vectors and animals, few human cases having been described. The aim of our study was to determine the seroprevalence of Rickettsia (spotted fever--SFG--and typhus--TG--groups) and Coxiella burnetii (Q fever agent) in residents of Buenos Aires city. The study involved 99 participants. Rickettsia IgG antibodies against SFG and TG were detected by IFA in 28.3% and 16.2% of serum samples, respectively. SFG titers were mostly 1/64 (53.6%) with a maximum of 1/512 (3.5%) whereas TG titers ranged between 1/64 (62.5%) and 1/256 (6.3%). Only one sample showed a titer of 1/32 for C. burnetii (phases I and II). The circulation of these pathogens in urban areas such as the city of Buenos Aires should be considered by health services, especially at the primary care level. PMID:26616661

  4. Prevalence of Rickettsia species in Dermacentor variabilis ticks from Ontario, Canada.

    PubMed

    Wood, Heidi; Dillon, Liz; Patel, Samir N; Ralevski, Filip

    2016-07-01

    Relatively little is known about the prevalence of rickettsial species in Dermacentor ticks in eastern Canada. In this study, Dermacentor ticks from the province of Ontario, Canada, were tested for the presence of spotted fever group rickettsial (SFGR) species, Coxiella burnetii and Francisella tularensis. Rickettsia rickettsii was not detected in any ticks tested, but R. montanensis was detected at a prevalence of 2.2% in D. variabilis (17/778). Two other SFGR species, R. parkeri and Candidatus R. andeanae, were detected individually in 2 Amblyomma maculatum ticks. Rickettsia peacockii, a non-pathogenic endosymbiont, was detected in two D. andersonii ticks. Given the highly abundant nature of D. variabilis, surveillance for human pathogens in this species of tick has important public health implications, but the lack of detection of known human pathogens indicates a low risk of infection via this tick species in Ontario. However, the detection of R. parkeri in an adventive A. maculatum tick indicates that health care providers should be aware of the possibility of spotted fever rickettsioses in individuals with a history of travel outside of Ontario and symptoms compatible with a spotted fever rickettsiosis. Coxiella burnetii and Francisella tularensis, human pathogens also potentially transmitted by D. variabilis, were not detected in a subset of the ticks. PMID:27318438

  5. "Christian carrying goomies".

    PubMed

    1994-01-01

    Dr. Passingan Usurup tells critics of his pragmatic approach on condom promotion that he is a Christian carrying condoms for Christ. He is head of the University of Papua New Guinea Medical Center and is credited with developing an AIDS/HIV policy for the Papua New Guinea Defence Force. The condoms were named Goomy and promoted at launching in 1992 in a blue packet under the slogan "The bond that guards." Goomy was chosen as the name because it is pidgin for rubber, chewing gum, and anything associated with rubber. Blue packets were chosen over the calls of most soldiers for a camouflage design because of its universal appeal as the color of the sea and sky and because it was the preference of women in the airlines. Once firmly ensconced in his role at the University, Usurup plans to develop a policy for students and staff and help to conduct AIDS prevention and education activities on campus. He will encourage students to test for HIV rather than highlighting the gloom and doom of infection and disease. PMID:12345555

  6. Absence of antibodies to Rickettsia spp., Bartonella spp., Ehrlichia spp. and Coxiella burnetii in Tahiti, French Polynesia

    PubMed Central

    2014-01-01

    Abtract Background In the Pacific islands countries and territories, very little is known about the incidence of infectious diseases due to zoonotic pathogens. To our knowledge, human infections due to Rickettsia spp., Coxiella burnetii, Ehrlichia spp. and Bartonella spp. have never been reported in French Polynesia; and infections due to C. burnetti have been reported worldwide except in New Zealand. To evaluate the prevalence of this disease, we conducted a serosurvey among French Polynesian blood donors. Methods The presence of immunoglobulin G antibodies against R. felis, R. typhi, R. conorii, C. burnetii, B. henselae, B. quintana, and E. chaffeensis was evaluated by indirect immunofluorescence assay in sera from 472 French Polynesian blood donors collected from 2011 to 2013. In addition, 178 ticks and 36 cat fleas collected in French Polynesia were also collected and tested by polymerase chain reaction to detect Rickettsia spp., B. henselae and Ehrlichia spp. Results None of the blood donors had antibodies at a significant level against Rickettsia spp., Coxiella burnetii, Ehrlichia spp. and Bartonella spp. All tested ticks and cat fleas were PCR-negative for Rickettsia spp., B. henselae, and Ehrlichia spp. Conclusion We cannot conclude that these pathogens are absent in French Polynesia but, if present, their prevalence is probably very low. C. burnetii has been reported worldwide except in New Zealand. It may also be absent from French Polynesia. PMID:24885466

  7. Infection of the whitefly Bemisia tabaci with Rickettsia spp. alters its interactions with Tomato yellow leaf curl virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. Here we report that infection with Rickettsia spp., a facultative endosymbiont of whiteflies...

  8. Multispacer Typing (MST) of Spotted Fever Group Rickettsiae Isolated from Humans and Rats in Chengmai County, Hainan Province, China.

    PubMed

    Cheng, Xueqin; Jin, Yuming; Lao, Shijun; Huang, Changhe; Huang, Fang; Jia, Pengben; Zhang, Lijuan

    2014-09-01

    Spotted fever caused by spotted fever group rickettsiae (SFGR) is found throughout China. During 2007-2008, 28 human SFGR isolates and 34 rat SFGR isolates including 15 isolates from Rattus fulvescens, 5 isolates from R. edwardsi, 7 isolates from Callosciurus erythraeus roberti and 7 isolates from Dremomys rufigenis) were obtained from L929 cell culture. Previous research indicated that the 62 strains of SFGR mentioned above shared not only the same serophenotype but also 100% of identity sequences of 16S rRNA, gltA, ompA, groEL and 17KD, which enabled us to apply multispacer typing (MST) to the 62 SFGR isolates in the study. Six primer pairs, which were used for typing of Rickettsia rickettsii and Rickettsia conorii, were chosen, and the results exhibited greater nucleotide polymorphisms among the 62 isolates tested. A total of 48 distinct genotypes were identified. The dominant genotype, represented by h3 isolates, accounted for 21.7% (13/60) of the isolates tested, and the remaining 47 genotypes were all unique. Phylogenetic analysis showed that all the 48 genotypes could be classified in the same clade, while the genetically related strain, R. heilongjiangensis, was close but not the same as the cluster. We concluded that the genetically diverse of spotted fever group rickettsiae strains are endemic in Chengmai County, Hainan Province, China. PMID:25324688

  9. Genome Sequencing of Four Strains of Rickettsia prowazekii, the Causative Agent of Epidemic Typhus, Including One Flying Squirrel Isolate.

    PubMed

    Bishop-Lilly, Kimberly A; Ge, Hong; Butani, Amy; Osborne, Brian; Verratti, Kathleen; Mokashi, Vishwesh; Nagarajan, Niranjan; Pop, Mihai; Read, Timothy D; Richards, Allen L

    2013-01-01

    Rickettsia prowazekii is a notable intracellular pathogen, the agent of epidemic typhus, and a potential biothreat agent. We present here whole-genome sequence data for four strains of R. prowazekii, including one from a flying squirrel. PMID:23814035

  10. RC1339/APRc from Rickettsia conorii is a novel aspartic protease with properties of retropepsin-like enzymes.

    PubMed

    Cruz, Rui; Huesgen, Pitter; Riley, Sean P; Wlodawer, Alexander; Faro, Carlos; Overall, Christopher M; Martinez, Juan J; Simões, Isaura

    2014-08-01

    Members of the species Rickettsia are obligate intracellular, gram-negative, arthropod-borne pathogens of humans and other mammals. The life-threatening character of diseases caused by many Rickettsia species and the lack of reliable protective vaccine against rickettsioses strengthens the importance of identifying new protein factors for the potential development of innovative therapeutic tools. Herein, we report the identification and characterization of a novel membrane-embedded retropepsin-like homologue, highly conserved in 55 Rickettsia genomes. Using R. conorii gene homologue RC1339 as our working model, we demonstrate that, despite the low overall sequence similarity to retropepsins, the gene product of rc1339 APRc (for Aspartic Protease from Rickettsia conorii) is an active enzyme with features highly reminiscent of this family of aspartic proteases, such as autolytic activity impaired by mutation of the catalytic aspartate, accumulation in the dimeric form, optimal activity at pH 6, and inhibition by specific HIV-1 protease inhibitors. Moreover, specificity preferences determined by a high-throughput profiling approach confirmed common preferences between this novel rickettsial enzyme and other aspartic proteases, both retropepsins and pepsin-like. This is the first report on a retropepsin-like protease in gram-negative intracellular bacteria such as Rickettsia, contributing to the analysis of the evolutionary relationships between the two types of aspartic proteases. Additionally, we have also shown that APRc is transcribed and translated in R. conorii and R. rickettsii and is integrated into the outer membrane of both species. Finally, we demonstrated that APRc is sufficient to catalyze the in vitro processing of two conserved high molecular weight autotransporter adhesin/invasion proteins, Sca5/OmpB and Sca0/OmpA, thereby suggesting the participation of this enzyme in a relevant proteolytic pathway in rickettsial life-cycle. As a novel bona fide member

  11. RC1339/APRc from Rickettsia conorii Is a Novel Aspartic Protease with Properties of Retropepsin-Like Enzymes

    PubMed Central

    Cruz, Rui; Huesgen, Pitter; Riley, Sean P.; Wlodawer, Alexander; Faro, Carlos; Overall, Christopher M.; Martinez, Juan J.; Simões, Isaura

    2014-01-01

    Members of the species Rickettsia are obligate intracellular, gram-negative, arthropod-borne pathogens of humans and other mammals. The life-threatening character of diseases caused by many Rickettsia species and the lack of reliable protective vaccine against rickettsioses strengthens the importance of identifying new protein factors for the potential development of innovative therapeutic tools. Herein, we report the identification and characterization of a novel membrane-embedded retropepsin-like homologue, highly conserved in 55 Rickettsia genomes. Using R. conorii gene homologue RC1339 as our working model, we demonstrate that, despite the low overall sequence similarity to retropepsins, the gene product of rc1339 APRc (for Aspartic Protease from Rickettsia conorii) is an active enzyme with features highly reminiscent of this family of aspartic proteases, such as autolytic activity impaired by mutation of the catalytic aspartate, accumulation in the dimeric form, optimal activity at pH 6, and inhibition by specific HIV-1 protease inhibitors. Moreover, specificity preferences determined by a high-throughput profiling approach confirmed common preferences between this novel rickettsial enzyme and other aspartic proteases, both retropepsins and pepsin-like. This is the first report on a retropepsin-like protease in gram-negative intracellular bacteria such as Rickettsia, contributing to the analysis of the evolutionary relationships between the two types of aspartic proteases. Additionally, we have also shown that APRc is transcribed and translated in R. conorii and R. rickettsii and is integrated into the outer membrane of both species. Finally, we demonstrated that APRc is sufficient to catalyze the in vitro processing of two conserved high molecular weight autotransporter adhesin/invasion proteins, Sca5/OmpB and Sca0/OmpA, thereby suggesting the participation of this enzyme in a relevant proteolytic pathway in rickettsial life-cycle. As a novel bona fide member

  12. Molecular Detection of Zoonotic Rickettsiae and Anaplasma spp. in Domestic Dogs and Their Ectoparasites in Bushbuckridge, South Africa.

    PubMed

    Kolo, Agatha O; Sibeko-Matjila, Kgomotso P; Maina, Alice N; Richards, Allen L; Knobel, Darryn L; Matjila, Paul T

    2016-04-01

    Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-borne and can cause mild to fatal diseases in humans worldwide. There is little information on the zoonotic rickettsial pathogens that may be harbored by dogs from rural localities in South Africa. To characterize rickettsial pathogens infecting dogs, we screened 141 blood samples, 103 ticks, and 43 fleas collected from domestic dogs in Bushbuckridge Municipality, Mpumalanga Province of South Africa, between October 2011 and May 2012 using the reverse line blot (RLB) and Rickettsia genus and species-specific quantitative real-time PCR (qPCR) assays. Results from RLB showed that 49% of blood samples and 30% of tick pools were positive for the genus-specific probes for Ehrlichia/Anaplasma; 16% of the blood samples were positive for Ehrlichia canis. Hemoparasite DNA could not be detected in 36% of blood samples and 30% of tick pools screened. Seven (70%) tick pools and both flea pools were positive for Rickettsia spp; three (30%) tick pools were positive for Rickettsia africae; and both flea pools (100%) were positive for Rickettsia felis. Sequencing confirmed infection with R. africae and Candidatus Rickettsia asemboensis; an R. felis-like organism from one of the R. felis-positive flea pools. Anaplasma sp. South Africa dog strain (closely related to Anaplasma phagocytophilum), A. phagocytophilum, and an Orientia tsutsugamushi-like sequence were identified from blood samples. The detection of emerging zoonotic agents from domestic dogs and their ectoparasites in a rural community in South Africa highlights the potential risk of human infection that may occur with these pathogens. PMID:26974185

  13. The Sca2 Autotransporter Protein from Rickettsia conorii Is Sufficient To Mediate Adherence to and Invasion of Cultured Mammalian Cells▿

    PubMed Central

    Cardwell, Marissa M.; Martinez, Juan J.

    2009-01-01

    Obligate intracellular bacteria of the genus Rickettsia must adhere to and invade the host endothelium in order to establish an infection. These processes require the interaction of rickettsial surface proteins with mammalian host cell receptors. A previous bioinformatic analysis of sequenced rickettsial species identified a family of at least 17 predicted “surface cell antigen” (sca) genes whose products resemble autotransporter proteins. Two members of this family, rOmpA and rOmpB of spotted fever group (SFG) rickettsiae have been identified as adhesion and invasion factors, respectively; however, little is known about the putative functions of the other sca gene products. An intact sca2 gene is found in the majority of pathogenic SFG rickettsiae and, due to its sequence conservation among these species, we predict that Sca2 may play an important function at the rickettsial surface. Here we have shown that sca2 is transcribed and expressed in Rickettsia conorii and have used a heterologous gain-of-function assay in E. coli to determine the putative role of Sca2. Using this system, we have demonstrated that expression of Sca2 at the outer membrane of nonadherent, noninvasive E. coli is sufficient to mediate adherence to and invasion of a panel of mammalian cells, including endothelial cells. Furthermore, soluble Sca2 protein is capable of diminishing R. conorii invasion of cultured mammalian cells. This is the first evidence that Sca2 participates in the interaction between SFG rickettsiae and host cells and suggests that in addition to other surface proteins, Sca2 may play a critical role in rickettsial pathogenesis. PMID:19805531

  14. Experimental infection of ectoparasitic arthropods with Rickettsia prowazekii (GvF-16 strain) and transmission to flying squirrels.

    PubMed

    Bozeman, F M; Sonenshine, D E; Williams, M S; Chadwick, D P; Lauer, D M; Elisberg, B L

    1981-01-01

    Epizootiologic studies conducted during the past few years showed the existence of widespread natural infection of the southern flying squirrel, Glaucomys volans, with epidemic typhus rickettsiae, Rickettsia prowazekii. The ecological findings strongly implicated transmission of the etiologic agent by an arthropod vector. Studies were conducted under controlled laboratory conditions to determine whether ectoparasites naturally associated with flying squirrels (squirrel fleas, lice, mites and ticks) were capable of acquiring, maintaining and transmitting the infection. Also studied were the cat flea, oriental rat flea and the human body louse. Flying squirrels inoculated with the GvF-16 strain of R. prowazekii circulated rickettsiae in their blood for 2-3 weeks, thus providing ample opportunity for arthropods feeding on them to become infected. The results with Dermacentor variabilis ticks indicated that the rickettsiae did not consistently survive in this insect and were not passed to the eggs of adult females that had been infected subcuticularly. Mites became infected by feeding on infectious blood but failed to sustain the infection. Also, mites fed on an infected flying squirrel did not transmit the infection to a normal squirrel. Squirrel, cat, and oriental rat fleas readily became infected by feeding on a rickettsemic host or on infectious blood through membranes, but failed to transmit the infection to susceptible flying squirrels. In the studies with flying squirrel lice, however, transmission of epidemic typhus from infected to uninfected flying squirrels was demonstrated. Infection of the human body louse with the GvF-16 flying squirrel strain of R. prowazekii was similar to that previously observed with classical human strains, viz., multiplication of the rickettsiae and excretion in the feces. PMID:6782900

  15. Candidatus Rickettsia andeanae, a spotted fever group agent infecting Amblyomma parvum ticks in two Brazilian biomes

    PubMed Central

    Nieri-Bastos, Fernanda Aparecida; Lopes, Marcos Gomes; Cançado, Paulo Henrique Duarte; Rossa, Giselle Ayres Razera; Faccini, João Luiz Horácio; Gennari, Solange Maria; Labruna, Marcelo Bahia

    2014-01-01

    Adult ticks of the species Amblyomma parvum were collected from the vegetation in the Pantanal biome (state of Mato Grosso do Sul) and from horses in the Cerrado biome (state of Piauí) in Brazil. The ticks were individually tested for rickettsial infection via polymerase chain reaction (PCR) targeting three rickettsial genes, gltA, ompA and ompB. Overall, 63.5% (40/63) and 66.7% (2/3) of A. parvum ticks from Pantanal and Cerrado, respectively, contained rickettsial DNA, which were all confirmed by DNA sequencing to be 100% identical to the corresponding fragments of the gltA, ompA and ompB genes of Candidatus Rickettsia andeanae. This report is the first to describe Ca. R. andeanae in Brazil. PMID:24714968

  16. A case of uveitis due to Rickettsia conorii infection in Southeastern France.

    PubMed

    Caisso, Cecile; Payan, Jacques; Dunais, Brigitte; Neri, Dominique; Vassallo, Matteo

    2016-03-01

    We describe a case of skin rash and bilateral uveitis secondary to Rickettsia conorii infection. A 60-year-old female patient, living in the rural hinterland of Cannes, was referred to our hospital in mid-August 2012 for skin rash, fever, and arthromyalgia. Blood tests showed increased inflammatory markers, hepatic cytolysis and anicteric cholestasis. Ophthalmic examination revealed bilateral papillitis and focal chorio-retinitis. Fluoroscopic angiography demonstrated early hypofluorescence, with a few arteriolar occlusions, and subsequent hyperfluorescence and focal vasculitis. R. conorii antibodies were identified by immunofluorescence antibody test. Investigation of other infective agents and the immunological panel were negative. A 2-week course of doxycycline 200 mg/day was prescribed, and fever rapidly subsided, the skin rash resolved and vision improved. Ophthalmic examination a month and a half later showed almost all retinal lesions had disappeared and inflammation markers had returned to normal. PMID:26711674

  17. A Confirmed Case of Rickettsia parkeri Infection in a Traveler from Uruguay

    PubMed Central

    Portillo, Aránzazu; García-García, Concepción; Sanz, M. Mercedes; Santibáñez, Sonia; Venzal, José M.; Oteo, José A.

    2013-01-01

    The first confirmed case of Rickettsia parkeri infection in Uruguay is reported. To date, in South America, molecularly confirmed cases of human infection have been found in Argentina and probably, Brazil. Our patient returned to Spain after a 7-day trip to Colonia Suiza (Southwestern Uruguay). He presented fever (39°C), chills, and two eschars (tache noire-like) surrounded by an indurated, erythematous halo on the inner side of the left ankle besides a maculopapular rash on the legs. After treatment with doxycycline for 7 days, he fully recovered. R. parkeri infection was diagnosed by molecular-based detection of the microorganism in a swab specimen of the eschar. Diagnosis was supported by seroconversion between acute- and convalescent-phase sera specimens. PMID:24166040

  18. Feeding Period Required by Amblyomma aureolatum Ticks for Transmission of Rickettsia rickettsii to Vertebrate Hosts

    PubMed Central

    Saraiva, Danilo G.; Soares, Herbert S.; Soares, João Fábio

    2014-01-01

    Rocky Mountain spotted fever is endemic to the São Paulo metropolitan area, Brazil, where the etiologic agent, Rickettsia rickettsii, is transmitted to humans by adult Amblyomma aureolatum ticks. We determined the minimal feeding period required by A. aureolatum nymphs and adults to transmit R. rickettsii to guinea pigs. Unfed nymphs and unfed adult ticks had to be attached to the host for >10 hours to transmit R. rickettsii. In contrast, fed ticks needed a minimum of 10 minutes of attachment to transmit R. rickettsii to hosts. Most confirmed infections of Rocky Mountain spotted fever in humans in the São Paulo metropolitan area have been associated with contact with domestic dogs, the main host of A. aureolatum adult ticks. The typical expectation that transmission of tickborne bacteria to humans as well as to dogs requires ≥2 hours of tick attachment may discourage persons from immediately removing them and result in transmission of this lethal bacterium. PMID:25148391

  19. Phylogeography of Rickettsia rickettsii Genotypes Associated with Fatal Rocky Mountain Spotted Fever

    PubMed Central

    Paddock, Christopher D.; Denison, Amy M.; Lash, R. Ryan; Liu, Lindy; Bollweg, Brigid C.; Dahlgren, F. Scott; Kanamura, Cristina T.; Angerami, Rodrigo N.; Pereira dos Santos, Fabiana C.; Brasil Martines, Roosecelis; Karpathy, Sandor E.

    2014-01-01

    Rocky Mountain spotted fever (RMSF), a tick-borne zoonosis caused by Rickettsia rickettsii, is among the deadliest of all infectious diseases. To identify the distribution of various genotypes of R. rickettsii associated with fatal RMSF, we applied molecular typing methods to samples of DNA extracted from formalin-fixed, paraffin-embedded tissue specimens obtained at autopsy from 103 case-patients from seven countries who died of RMSF. Complete sequences of one or more intergenic regions were amplified from tissues of 30 (29%) case-patients and revealed a distribution of genotypes consisting of four distinct clades, including the Hlp clade, regarded previously as a non-pathogenic strain of R. rickettsii. Distinct phylogeographic patterns were identified when composite case-patient and reference strain data were mapped to the state and country of origin. The phylogeography of R. rickettsii is likely determined by ecological and environmental factors that exist independently of the distribution of a particular tick vector. PMID:24957541

  20. Molecular Detection of Rickettsia felis in Humans, Cats, and Cat Fleas in Bangladesh, 2013-2014.

    PubMed

    Ahmed, Rajib; Paul, Shyamal Kumar; Hossain, Muhammad Akram; Ahmed, Salma; Mahmud, Muhammad Chand; Nasreen, Syeda Anjuman; Ferdouse, Faria; Sharmi, Rumana Hasan; Ahamed, Farid; Ghosh, Souvik; Urushibara, Noriko; Aung, Meiji Soe; Kobayashi, Nobumichi

    2016-05-01

    High prevalence of Rickettsia felis in patients with fever of unknown origin was revealed in the north-central Bangladesh from 2012 to 2013. Subsequently, in this study, prevalence of R. felis in cats and cat fleas (Ctenocephalides felis), together with febrile patients, was studied by PCR detection of 17 kDa antigen gene and DNA sequencing. R. felis was detected in 28% (28/100) and 21% (14/68) of cat blood and cat flea samples, respectively, whereas 42% (21/50) of patients were positive for R. felis. R. felis-positive cat fleas were detected at significantly higher rate on R. felis-positive cats. The results suggested a potential role of cats and cat fleas for transmission of R. felis to humans in Bangladesh. PMID:26901499

  1. High prevalence of Rickettsia africae variants in Amblyomma variegatum ticks from domestic mammals in rural western Kenya: implications for human health.

    PubMed

    Maina, Alice N; Jiang, Ju; Omulo, Sylvia A; Cutler, Sally J; Ade, Fredrick; Ogola, Eric; Feikin, Daniel R; Njenga, M Kariuki; Cleaveland, Sarah; Mpoke, Solomon; Ng'ang'a, Zipporah; Breiman, Robert F; Knobel, Darryn L; Richards, Allen L

    2014-10-01

    Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya. Of the 100 serum specimens tested from each species of domestic ruminant 43% of goats, 23% of sheep, and 1% of cattle had immunoglobulin G (IgG) antibodies to the SFG rickettsiae. None of these sera were positive for IgG against typhus group rickettsiae. We detected Rickettsia africae-genotype DNA in 92.6% of adult Amblyomma variegatum ticks collected from domestic ruminants, but found no evidence of the pathogen in blood specimens from cattle, goats, or sheep. Sequencing of a subset of 21 rickettsia-positive ticks revealed R. africae variants in 95.2% (20/21) of ticks tested. Our findings show a high prevalence of R. africae variants in A. variegatum ticks in western Kenya, which may represent a low disease risk for humans. This may provide a possible explanation for the lack of African tick-bite fever cases among febrile patients in Kenya. PMID:25325312

  2. Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES

    PubMed Central

    PENICHE-LARA, Gaspar; DZUL-ROSADO, Karla; PÉREZ-OSORIO, Carlos; ZAVALA-CASTRO, Jorge

    2015-01-01

    Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán. PMID:25923891

  3. Fluorescence Activated Cell Sorting of Rickettsia prowazekii-Infected Host Cells Based on Bacterial Burden and Early Detection of Fluorescent Rickettsial Transformants

    PubMed Central

    Driskell, Lonnie O.; Tucker, Aimee M.; Woodard, Andrew; Wood, Raphael R.; Wood, David O.

    2016-01-01

    Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate intracellular bacterium that replicates only within the cytosol of a eukaryotic host cell. Despite the barriers to genetic manipulation that such a life style creates, rickettsial mutants have been generated by transposon insertion as well as by homologous recombination mechanisms. However, progress is hampered by the length of time required to identify and isolate R. prowazekii transformants. To reduce the time required and variability associated with propagation and harvesting of rickettsiae for each transformation experiment, characterized frozen stocks were used to generate electrocompetent rickettsiae. Transformation experiments employing these rickettsiae established that fluorescent rickettsial populations could be identified using a fluorescence activated cell sorter within one week following electroporation. Early detection was improved with increasing amounts of transforming DNA. In addition, we demonstrate that heterogeneous populations of rickettsiae-infected cells can be sorted into distinct sub-populations based on the number of rickettsiae per cell. Together our data suggest the combination of fluorescent reporters and cell sorting represent an important technical advance that will facilitate isolation of distinct R. prowazekii mutants and allow for closer examination of the effects of infection on host cells at various infectious burdens. PMID:27010457

  4. TolC-Dependent Secretion of an Ankyrin Repeat-Containing Protein of Rickettsia typhi

    PubMed Central

    Rahman, M. Sayeedur; Ammerman, Nicole C.; Beier-Sexton, Magda; Ceraul, Shane M.; Gillespie, Joseph J.; Azad, Abdu F.

    2012-01-01

    Rickettsia typhi, the causative agent of murine (endemic) typhus, is an obligate intracellular pathogen with a life cycle involving both vertebrate and invertebrate hosts. In this study, we characterized a gene (RT0218) encoding a C-terminal ankyrin repeat domain-containing protein, named Rickettsia ankyrin repeat protein 1 (RARP-1), and identified it as a secreted effector protein of R. typhi. RT0218 showed differential transcript abundance at various phases of R. typhi intracellular growth. RARP-1 was secreted by R. typhi into the host cytoplasm during in vitro infection of mammalian cells. Transcriptional analysis revealed that RT0218 was cotranscribed with adjacent genes RT0217 (hypothetical protein) and RT0216 (TolC) as a single polycistronic mRNA. Given one of its functions as a facilitator of extracellular protein secretion in some Gram-negative bacterial pathogens, we tested the possible role of TolC in the secretion of RARP-1. Using Escherichia coli C600 and an isogenic tolC insertion mutant as surrogate hosts, our data demonstrate that RARP-1 is secreted in a TolC-dependent manner. Deletion of either the N-terminal signal peptide or the C-terminal ankyrin repeats abolished RARP-1 secretion by wild-type E. coli. Importantly, expression of R. typhi tolC in the E. coli tolC mutant restored the secretion of RARP-1, suggesting that TolC has a role in RARP-1 translocation across the outer membrane. This work implies that the TolC component of the putative type 1 secretion system of R. typhi is involved in the secretion process of RARP-1. PMID:22773786

  5. Liolaemus lizards (Squamata: Liolaemidae) as hosts for the nymph of Amblyomma parvitarsum (Acari: Ixodidae), with notes on Rickettsia infection.

    PubMed

    Muñoz-Leal, Sebastián; Tarragona, Evelina L; Martins, Thiago F; Martín, Claudia M; Burgos-Gallardo, Freddy; Nava, Santiago; Labruna, Marcelo B; González-Acuña, Daniel

    2016-10-01

    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. PMID:27406395

  6. Prevalence of antibodies against Rickettsia conorii, Babesia canis, Ehrlichia canis, and Anaplasma phagocytophilum antigens in dogs from the Stretto di Messina area (Italy).

    PubMed

    Pennisi, Maria-Grazia; Caprì, Alessandra; Solano-Gallego, Laia; Lombardo, Gabriella; Torina, Alessandra; Masucci, Marisa

    2012-12-01

    The aims of this study were to determine the seroprevalence for Rickettsia conorii, Ehrlichia canis, Anaplasma phagocytophilum, and Babesia canis in outdoor-kennelled dogs (n=249) from the Stretto di Messina (Italy) and to compare seroprevalence in 2 public shelters and 4 privately-owned kennels where different tick-preventive measures were implemented in order to focus on the specific sanitary risk posed by public shelters in southern Italy for tick-borne pathogens. R. conorii (72%) and B. canis (70%) were the most prevalent infections when compared to E. canis (46%) and A. phagocytophilum (38%). Seroprevalence for R. conorii, E. canis, and A. phagocytophilum was significantly higher in public shelters than in private kennels. However, B. canis seropositivity was similar in both types of kennels. In addition, in private kennels where a regular ectocide treatment was carried out by means of spot-on devices, dogs did not present E. canis and A. phagocytophilum antibodies. One hundred fifty-one dogs out of 249 (61%) were seropositive to more than one pathogen with R. conorii and B. canis the most common ones. Coinfections were more frequently found in public-shelter dogs. This study demonstrated high seroprevalences against R. conorii, B. canis, E. canis, and A. phagocytophilum in kennelled dogs from both coastal sites of the Stretto di Messina and the importance of regular tick-bite prevention by means of individual spot-on devices. PMID:23140895

  7. [BRILL-ZINSER DISEASE AS A CONSEQUENCE OF RICKETTSIA PROWAZEKII PERSISTENCE IN PREVIOUSLY ILL WHO HAVE HAD EPIDEMIC TYPHUS (EPIDEMIOLOGIC ASPECTS)].

    PubMed

    Tarasevich, I V; Shpynov, S N; Pantyukhina, A N

    2015-01-01

    Materials, that summarize data of original research and scientific literature on epidemiology and problems of persistence during epidemic typhus, whose causative agent (Rickettsia prowazekii) is reactivated in the organism of the previously ill and is manifested as Brill-Zinser disease, are presented. A retrospective analysis was carried out with the data obtained by Russian (All-Union) Centre for Rickettsioses during study of epidemiologic examination maps of 5705 typhus nidi and results of 19 463 blood sera analysis during study of immunologic structure of population in the territories of the former USSR for the period from 1970 to 1992. A decrease of epidemic typhus morbidity and an increase of the fraction of Brill-Zinser disease took place as a result of pediculosis corporis control. In separate territories specific weight of Brill-Zinser disease was 48% in 1952, up to 80% in 1969, and from 1977 all the ill were previously ill. However, during the perestroika period and afterwards, due to a reduction of economic and hygienic living conditions, appearance of refugees, the immune structure regarding typhus began to change. Due to the buildup of the population migration process and the presence of risk groups (refugees, homeless) among population of regions, where local wars are waged, the enhancement of methods of epidemic typhus and Brill-Zinser disease diagnostics and pediculosis corporis eradication is necessary. Study of R. prowazekii by molecular-genetics methods is necessary for complete understanding of its mechanism of persistence. PMID:26470431

  8. Rickettsia conorii infection stimulates the expression of ISG15 and ISG15 protease UBP43 in human microvascular endothelial cells

    PubMed Central

    Colonne, Punsiri M.; Sahni, Abha; Sahni, Sanjeev K.

    2011-01-01

    Rickettsia conorii, an obligate intracellular bacterium and the causative agent of Mediterranean spotted fever, preferentially infects microvascular endothelial cells of the mammalian hosts leading to onset of innate immune responses, characterized by the activation of intracellular signaling mechanisms, release of pro-inflammatory cytokines and chemokines, and killing of intracellular rickettsiae. Our recent studies have shown that interferon (IFN)-β, a cytokine traditionally considered to be involved in antiviral immunity, plays an important role in the autocrine/paracrine regulation of host defense mechanism and control of R. conorii growth in the host endothelial cells. Here, we show that R. conorii infection induces the expression of ISG15 (an interferon-stimulated gene coding a protein of 17 kD) and UBP43 (an ISG15-specific protease) at the levels of mRNA and protein and report the evidence of ISGylation of as yet unidentified target proteins in cultured human microvascular endothelium. Infection-induced expression of ISG15 and UBP43 requires intracellular replication of rickettsiae and production of IFN-β, because treatment with tetracycline and presence of an antibody capable of neutralizing IFN-β activity resulted in near complete attenuation of both responses. Inhibition of R. conorii-induced ISG15 by RNA interference results in significant increase in the extent of rickettsial replication, whereas UBP43 knockdown yields a reciprocal inhibitory effect. In tandem, these results demonstrate the stimulation of interferon-β-mediated innate immune mechanisms capable of perturbing the growth and replication of pathogenic rickettsiae and provide first evidence for ISG!5-mediated post-translational modification of host cellular proteins during infection with an intracellular bacterium. PMID:22100648

  9. Diversity of Bartonella and Rickettsia spp. in Bats and Their Blood-Feeding Ectoparasites from South Africa and Swaziland

    PubMed Central

    Dietrich, Muriel; Tjale, Mabotse A.; Weyer, Jacqueline; Kearney, Teresa; Seamark, Ernest C. J.; Nel, Louis H.; Monadjem, Ara; Markotter, Wanda

    2016-01-01

    In addition to several emerging viruses, bats have been reported to host multiple bacteria but their zoonotic threats remain poorly understood, especially in Africa where the diversity of bats is important. Here, we investigated the presence and diversity of Bartonella and Rickettsia spp. in bats and their ectoparasites (Diptera and Siphonaptera) collected across South Africa and Swaziland. We collected 384 blood samples and 14 ectoparasites across 29 different bat species and found positive samples in four insectivorous and two frugivorous bat species, as well as their Nycteribiidae flies. Phylogenetic analyses revealed diverse Bartonella genotypes and one main group of Rickettsia, distinct from those previously reported in bats and their ectoparasites, and for some closely related to human pathogens. Our results suggest a differential pattern of host specificity depending on bat species. Bartonella spp. identified in bat flies and blood were identical supporting that bat flies may serve as vectors. Our results represent the first report of bat-borne Bartonella and Rickettsia spp. in these countries and highlight the potential role of bats as reservoirs of human bacterial pathogens. PMID:26999518

  10. Molecular characterization of Rickettsia massiliae and Anaplasma platys infecting Rhipicephalus sanguineus ticks and domestic dogs, Buenos Aires (Argentina).

    PubMed

    Cicuttin, Gabriel L; Brambati, Diego F; Rodríguez Eugui, Juan I; Lebrero, Cecilia González; De Salvo, María N; Beltrán, Fernando J; Gury Dohmen, Federico E; Jado, Isabel; Anda, Pedro

    2014-09-01

    Rickettsioses, ehrlichioses and anaplasmoses are emerging diseases that are mainly transmitted by arthropods and that affect humans and animals. The aim of the present study was to use molecular techniques to detect and characterize those pathogens in dogs and ticks from Buenos Aires city. We studied 207 Rhipicephalus sanguineus ticks and 52 canine blood samples from poor neighborhoods of Buenos Aires city. The samples were molecularly screened for the genera Rickettsia, Ehrlichia, and Anaplasma by PCR and sequencing. DNA of Rickettsia massiliae (3.4%) and Anaplasma platys (13.5%) was detected in ticks and blood samples, respectively. For characterization, the positive samples were subjected to amplification of a fragment of the 190-kDa outer membrane protein gene (spotted fever group rickettsiae) and a fragment of the groESL gene (specific for A. platys). A phylogenetic tree was constructed using the neighbor-joining method, revealing that the sequences were closely related to those of strains from other geographic regions. The results indicate that human and animal pathogens are abundant in dogs and their ticks in Buenos Aires city and portray the potentially high risk of human exposure to infection with these agents, especially in poor neighborhoods, where there is close contact with animals in an environment of poor health conditions. PMID:24907186

  11. High Seroprevalence for Rickettsia rickettsii in Equines Suggests Risk of Human Infection in Silent Areas for the Brazilian Spotted Fever.

    PubMed

    Souza, Celso Eduardo; Camargo, Luciana Bonato; Pinter, Adriano; Donalisio, Maria Rita

    2016-01-01

    Equines play a role in the epidemiology of Brazilian spotted fever (BSF) since they are a primary host for the tick Amblyomma sculptum. We studied the seroprevalence for three species of Rickettsia in equines in four endemic (with human cases) and in four non-endemic areas (no human cases) in the Piracicaba River Basin, São Paulo, Brazil. A serological survey of 504 equines was performed: around 63 animals were sampled in each area and tested through indirect immunofluorescence assay for R. rickettsii, R. parkeri, and R. bellii in 2012-2013. Blood samples were seropositive for 183 equines (36.3%) in which 73 (39.9%) were from non-endemic areas. In the studied sites equines were highly exposed to Rickettsia infection ranging from 6.1% to 54.7%, with Geometric Mean Titers greater in endemic area (p = 0.012). Results suggest that Rickettsia may be more widespread than the surveillance of BSF has detected. These results highlight the need to include data on the seroprevalence of sentinel animals to improve human diagnoses and surveillance in areas with no reported human cases. PMID:27064788

  12. High Seroprevalence for Rickettsia rickettsii in Equines Suggests Risk of Human Infection in Silent Areas for the Brazilian Spotted Fever

    PubMed Central

    2016-01-01

    Equines play a role in the epidemiology of Brazilian spotted fever (BSF) since they are a primary host for the tick Amblyomma sculptum. We studied the seroprevalence for three species of Rickettsia in equines in four endemic (with human cases) and in four non-endemic areas (no human cases) in the Piracicaba River Basin, São Paulo, Brazil. A serological survey of 504 equines was performed: around 63 animals were sampled in each area and tested through indirect immunofluorescence assay for R. rickettsii, R. parkeri, and R. bellii in 2012–2013. Blood samples were seropositive for 183 equines (36.3%) in which 73 (39.9%) were from non-endemic areas. In the studied sites equines were highly exposed to Rickettsia infection ranging from 6.1% to 54.7%, with Geometric Mean Titers greater in endemic area (p = 0.012). Results suggest that Rickettsia may be more widespread than the surveillance of BSF has detected. These results highlight the need to include data on the seroprevalence of sentinel animals to improve human diagnoses and surveillance in areas with no reported human cases. PMID:27064788

  13. Diversity of Bartonella and Rickettsia spp. in Bats and Their Blood-Feeding Ectoparasites from South Africa and Swaziland.

    PubMed

    Dietrich, Muriel; Tjale, Mabotse A; Weyer, Jacqueline; Kearney, Teresa; Seamark, Ernest C J; Nel, Louis H; Monadjem, Ara; Markotter, Wanda

    2016-01-01

    In addition to several emerging viruses, bats have been reported to host multiple bacteria but their zoonotic threats remain poorly understood, especially in Africa where the diversity of bats is important. Here, we investigated the presence and diversity of Bartonella and Rickettsia spp. in bats and their ectoparasites (Diptera and Siphonaptera) collected across South Africa and Swaziland. We collected 384 blood samples and 14 ectoparasites across 29 different bat species and found positive samples in four insectivorous and two frugivorous bat species, as well as their Nycteribiidae flies. Phylogenetic analyses revealed diverse Bartonella genotypes and one main group of Rickettsia, distinct from those previously reported in bats and their ectoparasites, and for some closely related to human pathogens. Our results suggest a differential pattern of host specificity depending on bat species. Bartonella spp. identified in bat flies and blood were identical supporting that bat flies may serve as vectors. Our results represent the first report of bat-borne Bartonella and Rickettsia spp. in these countries and highlight the potential role of bats as reservoirs of human bacterial pathogens. PMID:26999518

  14. On fast carry select adders

    NASA Technical Reports Server (NTRS)

    Shamanna, M.; Whitaker, S.

    1992-01-01

    This paper presents an architecture for a high-speed carry select adder with very long bit lengths utilizing a conflict-free bypass scheme. The proposed scheme has almost half the number of transistors and is faster than a conventional carry select adder. A comparative study is also made between the proposed adder and a Manchester carry chain adder which shows that the proposed scheme has the same transistor count, without suffering any performance degradation, compared to the Manchester carry chain adder.

  15. High detection rate of Rickettsia africae in Amblyomma variegatum but low prevalence of anti-rickettsial antibodies in healthy pregnant women in Madagascar.

    PubMed

    Keller, Christian; Krüger, Andreas; Schwarz, Norbert Georg; Rakotozandrindrainy, Raphael; Rakotondrainiarivelo, Jean Philibert; Razafindrabe, Tsiry; Derschum, Henri; Silaghi, Cornelia; Pothmann, Daniela; Veit, Alexandra; Hogan, Benedikt; May, Jürgen; Girmann, Mirko; Kramme, Stefanie; Fleischer, Bernhard; Poppert, Sven

    2016-02-01

    Tick-borne spotted fever group (SFG) rickettsioses are emerging infectious diseases in Sub-Saharan Africa. In Madagascar, the endemicity of tick-borne rickettsiae and their vectors has been incompletely studied. The first part of the present study was conducted in 2011 and 2012 to identify potential anthropophilic tick vectors for SFG rickettsiae on cattle from seven Malagasy regions, and to detect and characterize rickettsiae in these ticks. Amblyomma variegatum was the only anthropophilic tick species found on 262 cattle. Using a novel ompB-specific qPCR, screening for rickettsial DNA was performed on 111 A. variegatum ticks. Rickettsial DNA was detected in 96 of 111 ticks studied (86.5%). Rickettsia africae was identified as the only infecting rickettsia using phylogenetic analysis of ompA and ompB gene sequences and three variable intergenic spacers from 11 ticks. The second part of the study was a cross-sectional survey for antibodies against SFG rickettsiae in plasma samples taken from healthy, pregnant women at six locations in Madagascar, two at sea level and four between 450 and 1300m altitude. An indirect fluorescent antibody test with Rickettsia conorii as surrogate SFG rickettsial antigen was used. We found R. conorii-seropositives at all altitudes with prevalences between 0.5% and 3.1%. Our results suggest that A. variegatum ticks highly infected with R. africae are the most prevalent cattle-associated tick vectors for SFG rickettsiosis in Madagascar. Transmission of SFG rickettsiosis to humans occurs at different altitudes in Madagascar and should be considered as a relevant cause of febrile diseases. PMID:26318262

  16. Development and Validation of an Improved PCR Method Using the 23S-5S Intergenic Spacer for Detection of Rickettsiae in Dermacentor variabilis Ticks and Tissue Samples from Humans and Laboratory Animals

    PubMed Central

    Kakumanu, Madhavi L.; Ponnusamy, Loganathan; Sutton, Haley T.; Meshnick, Steven R.; Nicholson, William L.

    2016-01-01

    A novel nested PCR assay was developed to detect Rickettsia spp. in ticks and tissue samples from humans and laboratory animals. Primers were designed for the nested run to amplify a variable region of the 23S-5S intergenic spacer (IGS) of Rickettsia spp. The newly designed primers were evaluated using genomic DNA from 11 Rickettsia species belonging to the spotted fever, typhus, and ancestral groups and, in parallel, compared to other Rickettsia-specific PCR targets (ompA, gltA, and the 17-kDa protein gene). The new 23S-5S IGS nested PCR assay amplified all 11 Rickettsia spp., but the assays employing other PCR targets did not. The novel nested assay was sensitive enough to detect one copy of a cloned 23S-5S IGS fragment from “Candidatus Rickettsia amblyommii.” Subsequently, the detection efficiency of the 23S-5S IGS nested assay was compared to those of the other three assays using genomic DNA extracted from 40 adult Dermacentor variabilis ticks. The nested 23S-5S IGS assay detected Rickettsia DNA in 45% of the ticks, while the amplification rates of the other three assays ranged between 5 and 20%. The novel PCR assay was validated using clinical samples from humans and laboratory animals that were known to be infected with pathogenic species of Rickettsia. The nested 23S-5S IGS PCR assay was coupled with reverse line blot hybridization with species-specific probes for high-throughput detection and simultaneous identification of the species of Rickettsia in the ticks. “Candidatus Rickettsia amblyommii,” R. montanensis, R. felis, and R. bellii were frequently identified species, along with some potentially novel Rickettsia strains that were closely related to R. bellii and R. conorii. PMID:26818674

  17. Spotted fever group Rickettsia in small rodents from areas of low endemicity for Brazilian spotted fever in the eastern region of Minas Gerais State, Brazil.

    PubMed

    Milagres, Bruno S; Padilha, Amanda F; Montandon, Carlos E; Freitas, Renata N; Pacheco, Richard; Walker, David H; Labruna, Marcelo B; Mafra, Cláudio L; Galvão, Márcio A M

    2013-05-01

    We investigated the humoral immune response against different species of Rickettsia in serum samples from small rodents collected in two areas of a silent focus for Brazilian spotted fever in the eastern region of Minas Gerais State, Brazil. Sera samples were analyzed by indirect immunofluorescence assay using antigens from Rickettsia species of the spotted fever, ancestral, and transition groups. Titers ≥ 1:64 were considered positive. In Santa Cruz do Escalvado, 94% (30 of 32) of the samples collected from Rattus rattus, 22% (5 of 23) from Nectomys squamipes, and 80% (4 of 5) from Akodon sp., reacted by indirect immunofluorescence assay with Rickettsia antigens of the spotted fever group. In the municipality of Pingo D'Água, 84% (26 of 31) of the samples collected from R. rattus, 86% (6 of 7) of the samples from Oryzomys subflavus, 86% (6 of 7) from N. squamipes, and 100% (1 of 1) from Bolomys sp. contained antibodies that reacted with rickettsial antigens of the spotted fever group. These results demonstrated the previous exposure of small rodents to spotted fever group Rickettsia, suggesting the participation of these animals in the natural history of these rickettsiae in this region. PMID:23509125

  18. Spotted Fever Group Rickettsia in Small Rodents from Areas of Low Endemicity for Brazilian Spotted Fever in the Eastern Region of Minas Gerais State, Brazil

    PubMed Central

    Milagres, Bruno S.; Padilha, Amanda F.; Montandon, Carlos E.; Freitas, Renata N.; Pacheco, Richard; Walker, David H.; Labruna, Marcelo B.; Mafra, Cláudio L.; Galvão, Márcio A. M.

    2013-01-01

    We investigated the humoral immune response against different species of Rickettsia in serum samples from small rodents collected in two areas of a silent focus for Brazilian spotted fever in the eastern region of Minas Gerais State, Brazil. Sera samples were analyzed by indirect immunofluorescence assay using antigens from Rickettsia species of the spotted fever, ancestral, and transition groups. Titers ≥ 1:64 were considered positive. In Santa Cruz do Escalvado, 94% (30 of 32) of the samples collected from Rattus rattus, 22% (5 of 23) from Nectomys squamipes, and 80% (4 of 5) from Akodon sp., reacted by indirect immunofluorescence assay with Rickettsia antigens of the spotted fever group. In the municipality of Pingo D'Água, 84% (26 of 31) of the samples collected from R. rattus, 86% (6 of 7) of the samples from Oryzomys subflavus, 86% (6 of 7) from N. squamipes, and 100% (1 of 1) from Bolomys sp. contained antibodies that reacted with rickettsial antigens of the spotted fever group. These results demonstrated the previous exposure of small rodents to spotted fever group Rickettsia, suggesting the participation of these animals in the natural history of these rickettsiae in this region. PMID:23509125

  19. Rickettsia helvetica and R. monacensis infections in immature Ixodes ricinus ticks derived from sylvatic passerine birds in west-central Poland.

    PubMed

    Biernat, Beata; Stańczak, Joanna; Michalik, Jerzy; Sikora, Bożena; Cieniuch, Stella

    2016-09-01

    The aim of this study was to assess the importance of forest passerine birds in spreading ixodid ticks infected with rickettsiae of spotted fever group (SFG) in sylvatic habitats in western Poland. In total, 834 immature Ixodes ricinus ticks were found on 64 birds of 11 species which were captured during the tick-questing season between May and September of 2006. Ground-foraging passerines hosted most of the ticks compared with arboreal species, and therefore, only the former group was included into a detailed analysis. Significant predominance of larvae over nymphs was observed (581 vs. 253, respectively). Blackbirds and song thrushes hosted 82 % (n = 681) of the ticks collected from all infested passerines. The overall prevalence range of SF rickettsiae (including Rickettsia helvetica and Rickettsia monacensis) in bird-derived ticks was 10.5-26.9 %, exceeding that in questing ticks, and in ticks feeding on rodents and deer reported earlier from the same study area. This high prevalence of infection in immature I. ricinus ticks feeding on passerine birds strongly implies that they are involved in the enzootic maintenance of spotted fever group rickettsiae in the tick vector populations occurring in sylvatic habitats. PMID:27164834

  20. [Polypeptide and phospholipid composition of the Rickettsia prowazekii membrane and its immunogenic properties].

    PubMed

    Zezerov, E G; Loginov, V S; Berezneva, A S

    1985-06-01

    The composition of the cell membrane in R. prowazekii strain Breinl has been studied by the methods of electrophoresis in 7.5% polyacrylamide gel with 0.1% sodium dodecyl sulfate, iodination with Na125I in the presence of chloramine T or lactoperoxidase and the thin-layer chromatography of the common lipid fraction. Of six major polypeptides contained in whole rickettsial particles (3, 16, 26, 27, 28, 29), five polypeptides (3, 26, 27, 28, 29) making up 54% of all polypeptides of purified rickettsiae have been detected in membrane preparations obtained by either treatment. The molecular weights of these membrane polypeptides are, respectively, 133600, 34000, 29600, 21500 and 12400 daltons. The main membrane phospholipids are phosphatidylethanolamine (68.4%), phosphatidylglycerol (17.2%), phosphatidylcholine (5.1%) and cardiolipin (2.1%). The presence of cholesterol has also been established. The preparations of R. prowazekii membranes and individual membrane polypeptides are immunogenic and induce the formation of specific antibodies in white mice. The preparations of both membranes and surface polypeptide 3 (glycoprotein) have been found to possess a certain protective activity: the effect of the protection of white mice inoculated with R. prowazekii culture has proved to be 64%. PMID:3929506

  1. Introduction to the alpha-proteobacteria: Wolbachia and Bartonella, Rickettsia, Brucella, Ehrlichia, and Anaplasma.

    PubMed

    Bowman, Dwight D

    2011-11-01

    Wolbachia is an obligate intracellular endosymbiont and likely mutualist living within the heartworm Dirofilaria immitis and a number of other filarial nematodes in the family Onchocercidae. The bacterial infection is passed from worm to worm transovarially; the organisms are in ovarian cells, the developing microfilariae, and multiply and persist in all later developmental stages through the mosquito and into the next host. Besides being present in the ovaries of the adult worms, they also are present in large numbers within the hypodermal tissues of the nematode. It is now know that these bacteria that were first observed in heartworms more than 30 years ago are actually related to similar Wolbachia bacteria that are found in arthropods. Wolbachia is an alpha-proteobacteria, and this group includes a number of important arthropod-transmitted bacterial agents of dogs and cats: Rickettsia rickettsii, R. felis, Anaplasma platys, Ehrlichia canis, E. chaffeensis, and E. ewingii. Alpha-proteobacteria are also important as obligate intracellular mutualists in plants in which they are responsible for nitrogen fixation. Recent work on the treatment of heartworms in dogs with doxycycline stems from related work with the human filarial nematode Onchocerca volvulus that causes river blindness in people. PMID:22152604

  2. Molecular evidence of Ehrlichia canis and Rickettsia massiliae in ixodid ticks of carnivores from South Hungary.

    PubMed

    Hornok, Sándor; Fuente, José; Horváth, Gábor; Fernández de Mera, Isabel G; Wijnveld, Michiel; Tánczos, Balázs; Farkas, Róbert; Jongejan, Frans

    2013-03-01

    To monitor the emergence of thermophilic, Mediterranean ixodid tick species and tick-borne pathogens in southern Hungary, 348 ticks were collected from shepherd dogs, red foxes and golden jackals during the summer of 2011. Golden jackals shared tick species with both the dog and the red fox in the region. Dermacentor nymphs were collected exclusively from dogs, and the sequence identification of these ticks indicated that dogs are preferred hosts of both D. reticulatus and D. marginatus nymphs, unlike previously reported. Subadults of three ixodid species were selected for reverse line blot hybridisation (RLB) analysis to screen their vector potential for 40 pathogens/groups. Results were negative for Anaplasma, Babesia and Theileria spp. Investigation of D. marginatus nymphs revealed the presence of Ehrlichia canis, Rickettsia massiliae and Borrelia afzelii for the first time in this tick species. These findings broaden the range of those tick-borne agents, which are typically transmitted by Rhipicephalus sanguineus, but may also have Dermacentor spp. as potential or alternative vectors. Ehrlichiacanis was also newly detected in Ixodes canisuga larvae from red foxes. In absence of transovarial transmission in ticks this implies that Eurasian red foxes may play a reservoir role in the epidemiology of canine ehrlichiosis. PMID:23439290

  3. Possible Role of Rickettsia felis in Acute Febrile Illness among Children in Gabon

    PubMed Central

    Mourembou, Gaël; Lekana-Douki, Jean Bernard; Mediannikov, Oleg; Nzondo, Sydney Maghendji; Kouna, Lady Charlene; Essone, Jean Claude Biteghe Bi; Fenollar, Florence

    2015-01-01

    Rickettsia felis has been reported to be a cause of fever in sub-Saharan Africa, but this association has been poorly evaluated in Gabon. We assessed the prevalence of this bacterium among children <15 years of age in 4 areas of Gabon; the locations were in urban, semiurban, and rural areas. DNA samples from 410 febrile children and 60 afebrile children were analyzed by quantitative PCR. Overall, the prevalence of R. felis among febrile and afebrile children was 10.2% (42/410 children) and 3.3% (2/60 children), respectively. Prevalence differed among febrile children living in areas that are urban (Franceville, 1.3% [1/77]), semiurban (Koulamoutou, 2.1% [3/141]), and rural (Lastourville, 11.2% [15/134]; Fougamou, 39.7% [23/58]). Furthermore, in a rural area (Fougamou), R. felis was significantly more prevalent in febrile (39.7% [23/58]) than afebrile children (5.0% [1/20]). Additional studies are needed to better understand the pathogenic role of R. felis in this part of the world. PMID:26402580

  4. Structural features of the O-antigen of Rickettsia typhi, the etiological agent of endemic typhus.

    PubMed

    Peturova, M; Vitiazeva, V; Toman, R

    2015-09-01

    Elucidation of the O-specific polysaccharide chain of lipopolysaccharide (LPS) from Rickettsia typhi, the etiological agent of endemic typhus, is described. Structural information was established by a combination of monosaccharide and methylation analyses of the O-chain, and by mass (MS) and nuclear magnetic resonance (NMR) spectrometries of oligosaccharides arised through its hydrofluoric (HF) acid degradation. Based on the combined data from these experiments, two major polymer populations of the O-specific chain have been determined with the following structural features: α-L-QuiNAc-(1→4)-[α-D-Glc-(1→3)-α-L-QuiNAc-(1→4)]n-α-D-Glc-(1→4)-α-D-Glc→, α-D-Glc-(1→3)-α-L-QuiNAc-(1→4)-[α-D-Glc-(1→3)-α-L-QuiNAc-(1→4)]n-α-D-Glc→. The linear backbone is most probably flanked with short side chains of D-GlcNAc-(1→3)-α-L-QuiNAc-(1→3)-D-GlcNAc→ that are attached to it via L-QuiNAc as a branching point. It is suggested that a dimer α-L-QuiNAc-(1→3)-α-D-GlcNAc may represent a common epitope in the O-antigens of Proteus vulgaris OX19 and R. typhi responsible for the observed serological cross-reactivity. PMID:26435145

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

    PubMed

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

    2016-04-01

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

  6. A Rickettsia Genome Overrun by Mobile Genetic Elements Provides Insight into the Acquisition of Genes Characteristic of an Obligate Intracellular Lifestyle

    PubMed Central

    Joardar, Vinita; Williams, Kelly P.; Driscoll, Timothy; Hostetler, Jessica B.; Nordberg, Eric; Shukla, Maulik; Walenz, Brian; Hill, Catherine A.; Nene, Vishvanath M.; Azad, Abdu F.; Sobral, Bruno W.; Caler, Elisabet

    2012-01-01

    We present the draft genome for the Rickettsia endosymbiont of Ixodes scapularis (REIS), a symbiont of the deer tick vector of Lyme disease in North America. Among Rickettsia species (Alphaproteobacteria: Rickettsiales), REIS has the largest genome sequenced to date (>2 Mb) and contains 2,309 genes across the chromosome and four plasmids (pREIS1 to pREIS4). The most remarkable finding within the REIS genome is the extraordinary proliferation of mobile genetic elements (MGEs), which contributes to a limited synteny with other Rickettsia genomes. In particular, an integrative conjugative element named RAGE (for Rickettsiales amplified genetic element), previously identified in scrub typhus rickettsiae (Orientia tsutsugamushi) genomes, is present on both the REIS chromosome and plasmids. Unlike the pseudogene-laden RAGEs of O. tsutsugamushi, REIS encodes nine conserved RAGEs that include F-like type IV secretion systems similar to that of the tra genes encoded in the Rickettsia bellii and R. massiliae genomes. An unparalleled abundance of encoded transposases (>650) relative to genome size, together with the RAGEs and other MGEs, comprise ∼35% of the total genome, making REIS one of the most plastic and repetitive bacterial genomes sequenced to date. We present evidence that conserved rickettsial genes associated with an intracellular lifestyle were acquired via MGEs, especially the RAGE, through a continuum of genomic invasions. Robust phylogeny estimation suggests REIS is ancestral to the virulent spotted fever group of rickettsiae. As REIS is not known to invade vertebrate cells and has no known pathogenic effects on I. scapularis, its genome sequence provides insight on the origin of mechanisms of rickettsial pathogenicity. PMID:22056929

  7. Evaluation of a new serological test for the detection of anti-Coxiella and anti-Rickettsia antibodies.

    PubMed

    Bizzini, Alain; Péter, Olivier; Baud, David; Edouard, Sophie; Meylan, Pascal; Greub, Gilbert

    2015-01-01

    Coxiella burnetii and members of the genus Rickettsia are obligate intracellular bacteria. Since cultivation of these organisms requires dedicated techniques, their diagnosis usually relies on serological or molecular biology methods. Immunofluorescence is considered the gold standard to detect antibody-reactivity towards these organisms. Here, we assessed the performance of a new automated epifluorescence immunoassay (InoDiag) to detect IgM and IgG against C. burnetii, Rickettsia typhi and Rickettsia conorii. Samples were tested with the InoDiag assay. A total of 213 sera were tested, of which 63 samples from Q fever, 20 from spotted fever rickettsiosis, 6 from murine typhus and 124 controls. InoDiag results were compared to micro-immunofluorescence. For acute Q fever, the sensitivity of phase 2 IgG was only of 30% with a cutoff of 1 arbitrary unit (AU). In patients with acute Q fever with positive IF IgM, sensitivity reached 83% with the same cutoff. Sensitivity for chronic Q fever was 100% whereas sensitivity for past Q fever was 65%. Sensitivity for spotted Mediterranean fever and murine typhus were 91% and 100%, respectively. Both assays exhibited a good specificity in control groups, ranging from 79% in sera from patients with unrelated diseases or EBV positivity to 100% in sera from healthy patients. In conclusion, the InoDiag assay exhibits an excellent performance for the diagnosis of chronic Q fever but a very low IgG sensitivity for acute Q fever likely due to low reactivity of phase 2 antigens present on the glass slide. This defect is partially compensated by the detection of IgM. Because it exhibits a good negative predictive value, the InoDiag assay is valuable to rule out a chronic Q fever. For the diagnosis of rickettsial diseases, the sensitivity of the InoDiag method is similar to conventional immunofluorescence. PMID:26432518

  8. Evaluation of Antibiotic Susceptibilities of Three Rickettsial Species Including Rickettsia felis by a Quantitative PCR DNA Assay

    PubMed Central

    Rolain, Jean-Marc; Stuhl, Laetitia; Maurin, Max; Raoult, Didier

    2002-01-01

    Rickettsiae grow only intracellularly, and the antibiotic susceptibilities of these bacteria have been assessed by either plaque, dye uptake, or immunofluorescence assays, which are time-consuming. We used a quantitative PCR (with the LightCycler instrument) to assess the levels of inhibition of Rickettisa felis, R. conorii, and R. typhi DNA synthesis in the presence of various antibiotics. We established the kinetics of rickettsial DNA during growth and showed that R. conorii grows more quickly than R. typhi in cell culture, with maximum replication occurring after 5 and 7 days, respectively. The MICs of the antibiotics tested for R. conorii and R. typhi by the quantitative PCR assay were similar to those previously obtained by plaque and dye uptake assays. We found that R. felis is susceptible to doxycycline, rifampin, thiamphenicol, and fluoroquinolones but not to gentamicin, erythromycin, amoxicillin, or trimethoprim-sulfamethoxazole. The resistance of this new species to erythromycin is consistent with its current taxonomic position within the spotted fever group. We believe that quantitative PCR could be used in the future to simplify and shorten antibiotic susceptibility assays of other rickettsiae and other strict intracellular pathogens. PMID:12183224

  9. The role of cottontail rabbits (Sylvilagus spp.) in the ecology of Rickettsia rickettsii in the United States.

    PubMed

    Burgdorfer, W; Cooney, J C; Mavros, A J; Jellison, W L; Maser, C

    1980-07-01

    Rocky Mountain (Sylvilagus nuttallii) and eastern (S. floridanus) cottontails were examined for their susceptibility to virulent and avirulent strains of the spotted fever agent, Rickettsia rickettsii. Both species of rabbits responded to inoculation of yolk sac suspensions containing 500 egg LD50 of either virulent or avirulent rickettsiae, with rickettsemias detectable as early as 3 days after inoculation and lasting up to 7 days. When fed upon by infected ticks, only one of three Rocky Mountain and one of four eastern cottontails developed rickettsemias detectable in embryonated hens' eggs. Rickettsial concentrations in the peripheral blood fo Rocky Mountain cottontails, infected either by syringe or by bites of one or more Dermacentor andersoni ticks harboring virulent R. rickettsii, were sufficient to infect simultaneously feeding normal larvae of this tick species. However, infection rates wre low and did not exceed 11.7%. In a single experiment, the bites of D. variabilis, infected with an avirulent strain of R. rickettsii, did not produce rickettsemias sufficient to infect normal D. variabilis larvae. These laboratory findings suggest that cottontail rabbits, although susceptible to R. rickettsii, do not serve as efficient reservoirs for infecting ticks. PMID:7406116

  10. Immunosuppression associated with the development of chronic infections with Rickettsia tsutsugamushi: adherent suppressor cell activity and macrophage activation.

    PubMed Central

    Jerrells, T R

    1985-01-01

    Measures of general immunocompetency such as lymphocyte responses to mitogens and alloantigens and the ability to produce antibody to T-dependent and T-independent antigens were evaluated during the development of chronic infections with Rickettsia tsutsugamushi resulting from subcutaneous infection of BALB/c mice. It was found that a transient immunosuppression was demonstrable regardless of the infecting strain of rickettsiae; however, the immunosuppression produced by the Karp and Kato strains was more pronounced and longer lived. As a marked splenomegaly resulting from inflammatory macrophage influx accompanied this immunosuppression, mitogen- and antigen-induced lymphocyte proliferation was also evaluated after adherent cell depletion or in the presence of indomethacin, and both treatments significantly improved the responses. Isolated splenic macrophages were shown to suppress the responses of lymphocytes from naive mice as well as to exhibit parameters of activation including tumor cell cytolysis and cytostasis and the ability to inhibit the replication of R. tsutsugamushi in vitro. These data suggest an association between macrophage activation involved in rickettsial clearance and a transient immunosuppression. PMID:2931378