Co-circulating microorganisms in questing Ixodes scapularis nymphs in Maryland

Ixodes scapularis can be infected with Borrelia burgdorferi, Anaplasma phagocytophilum, Bartonella spp., Babesia microti, and Rickettsia spp., including spotted-fever group Rickettsia. As all of these microorganisms have been reported in Maryland, the potential for these ticks to have concurrent infections exists in this region. To assess the frequency of these complex infections, 348 I. scapularis nymphs collected in 2003 were screened for these microorganisms by PCR with positives being confirmed by DNA sequencing. Borrelia burgdorferi was detected in 14.7% of nymphs. Anaplasma phagocytophilum (0.3%), Rickettsia spp. (19.5%), and an uncategorized agent (0.9%) was also detected. Dual infections were detected with B. burgdorferi and Rickettsia spp. as well as a triple infection with B. burgdorferi, Rickettsia spp., and an uncategorized agent. Infections with B. burgdorferi and Rickettsia spp. were statistically independent of one another. However, infection with B. burgdorferi and any one of these other microorganisms appears to occur more frequently than by chance alone, probably as a result of shared enzootic cycles. This study confirms that multiple microorganisms co-circulate with B. burgdorferi in I. scapularis in Maryland and demonstrates that Rickettsia spp. and B. burgdorferi circulate independently and at nearly equal frequencies, while A. phagocytophilum and other unrecognized organisms are less common.     

Louse-borne bacterial pathogens in lice (Phthiraptera) of rodents and cattle from Egypt

We collected 1,023 lice, representing 5 species, from rats and domestic cattle throughout 13 governorates in Egypt and tested these lice for Anaplasma marginale, Bartonella spp., Brucella spp., Borrelia recurrentis, Coxiella burnetii, Francisella tularensis, and Rickettsia spp. by PCR amplification and sequencing. Five different louse-borne bacterial agents were detected in lice from rodents or cattle, including "Bartonella rattimassiliensis", "B. phoceensis", and Bartonella sp. near Bartonella tribocorum, Coxiella burnetii, and Rickettsia typhi. More lice from governorates bordering the Mediterranean and Red Seas contained pathogens. Our data indicate that lice of urban and domestic animals harbor pathogenic or potentially pathogenic bacterial agents throughout Egypt.     

Tick-borne zoonotic bacteria in wild and domestic small mammals in northern Spain

The prevalence and diversity of tick-borne zoonotic bacteria (Borrelia spp., Anaplasma phagocytophilum, Coxiella burnetii, and spotted fever group rickettsiae) infecting 253 small mammals captured in the Basque Country (Spain) were assessed using PCR and reverse line blot hybridization. Trapping sites were selected around sheep farms (study 1, 2000 to 2002) and recreational parks (study 2, 2003 to 2005). The majority of the studied mammals (162) were wood mice (Apodemus sylvaticus), but six other different species were also analyzed: yellow-necked mice (Apodemus flavicollis), shrews (Crocidura russula and Sorex coronatus), bank voles (Clethrionomys glareolus), domestic mice (Mus domesticus), and moles (Talpa europaea). The results showed an infection rate ranging from 10.7% to 68.8%, depending on the small mammal species. One C. russula shrew and one A. sylvaticus mouse gave positive reactions for A. phagocytophilum, and C. burnetii was detected in two domestic mice and one A. sylvaticus mouse in a farm. The DNA of Borrelia spp. was detected in 67 animals (26.5%), most of them presenting positive hybridization with the probe for Borrelia sp. strain R57, the new Borrelia species previously detected in small mammals in our region. Furthermore, a second PCR and reverse line blot hybridization specific for B. burgdorferi sensu lato revealed the presence of Borrelia afzelii in 6.3% of C. glareolus voles and 14.3% of S. coronatus shrews. All small mammals were negative for spotted fever group rickettsiae. These results highlight the relevance of small mammals as reservoirs of some zoonotic bacteria.     

Infections and coinfections of questing Ixodes ricinus ticks by emerging zoonotic pathogens in Western Switzerland

In Europe, Ixodes ricinus is the vector of many pathogens of medical and veterinary relevance, among them Borrelia burgdorferi sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and Anaplasma phagocytophilum in questing ticks. In this study, questing nymph and adult I. ricinus ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of B. burgdorferi sensu lato, Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and A. phagocytophilum. B. burgdorferi sensu lato, Rickettsia spp., and "Candidatus Neoehrlichia mikurensis" were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively. Babesia- and A. phagocytophilum-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like Borrelia spielmanii, Borrelia lusitaniae, and Rickettsia monacensis, were identified. Infections with more than one pathogenic species, involving mostly Borrelia spp. and Rickettsia helvetica, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in I. ricinus in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite.     

Dog tick-borne diseases in Sicily

In Sicily many tick borne diseases are endemic, in particular way those that see like main carrier ticks that prefer, for their vital cycle, climatic conditions characterized by high temperatures and a warmth-humid atmosphere. The more important pathologies transmitted by ticks causing diseases in dogs are babesiosis and ehrlichiosis. Borrelia burgdorferi, Anaplasma phagocytophilum, Rickettsia conorii, Coxiella burnetii and tick transmitted encephalitis virus assume particular relevance because they are agents of zoonosis. Our centre, C.R.A.Ba.R.T, have conducted many researches and carried out many tests for diagnostic aim in order to estimate the spread of the main tick borne diseases in Sicilians' dogs. A study lead on 342 dogs has evidenced seroprevalence for Babesia canis, Ehrlichia canis and Rickettsia respective of 5.17%, 21.70% and 53.43%. A study on zoonotic agent seroprevalences in dogs gave the following percentages: C. burnetii 31.50%, R. conorii 73.60% and A. phagocytophilum 32.80%. The data carried out from IZS Sicily diagnostic service on 5,634 tests done in 2004-2005, confirm the experimental results on the presence of B. canis, E. canis, R. conorii, A. phagocytophilum, C. burnetii, Rickettsia spp., Anaplasma spp. and Ehrlichia spp. in all the Sicilian areas.     

Coexistence of emerging bacterial pathogens in Ixodes ricinus ticks in Serbia

The list of tick-borne pathogens is long, varied and includes viruses, bacteria, protozoa and nematodes. As all of these agents can exist in ticks, their co-infections have been previously reported. We studied co-infections of emerging bacterial pathogens (Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum and Francisella tularensis) in Ixodes ricinus ticks in Serbia. Using PCR technique, we detected species-specific sequences, rrf-rrl rDNA intergenic spacer for B. burgdorferi s.l., p44/msp2 paralogs for A. phagocytophilum, and the 17 kDa lipoprotein gene, TUL4, for F. tularensis, respectively, in total DNA extracted from the ticks. Common infections with more than one pathogen were detected in 42 (28.8%) of 146 infected I. ricinus ticks. Co-infections with two pathogens were present in 39 (26.7%) of infected ticks. Simultaneous presence of A. phagocytophilum and different genospecies of B. burgdorferi s.l. complex was recorded in 16 ticks, co-infection with different B. burgdorferi s. l. genospecies was found in 15 ticks and eight ticks harbored mixed infections with F. tularensis and B. burgdorferi s.l. genospecies. Less common were triple pathogen species infections, detected in three ticks, one infected with A. phagocytophilum / B. burgdorferi s.s. / B. lusitaniae and two infected with F. tularensis / B. burgdorferi s.s. / B. lusitaniae. No mixed infections of A. phagocytophilum and F. tularensis were detected.     

Cell-mediated immune response to high-passage Borrelia spirochetes in C57bl/6 mice is strictly dependent on antigen specificity

Inbred C57bl/6 mice were challenged with high-passage Borrelia afzelii, Borrelia garinii and Borrelia burgdorferi sensu stricto and tested for antigen specific T-cell response in vitro. Sonicated preparations of washed spirochetes were potent cell activators, capable of stimulating polyclonal proliferation after 72h of culture while increasing the incubation time up to 120h provoked specific cell-mediated response. Isolated murine spleocytes previously sensitized to B. burgdorferi sensu lato but not those from control mice could be induced for antigen-specific proliferation in vitro, as revealed by [3H]thymidine incorporation assay, Moreover, in mice presensitized to B. burgdorferi sensu lato, detectable cell-mediated response could be induced only with antigen preparations derived from a corresponding strain but not with those obtained from other Borrelia genospecies. The current study emphasises that the B. burgdorferi antigen-specific response may also be expected in different genospecies infections in men.     

Prevalence and distribution of Borrelia and Babesia species in ticks feeding on dogs in the U.K.

Ticks were collected during March–July 2015 from dogs by veterinarians throughout the U.K. and used to estimate current prevalences and distributions of pathogens. DNA was extracted from 4750 ticks and subjected to polymerase chain reaction and sequence analysis to identify Borrelia burgdorferi sensu lato (Spirochaetales: Spirochaetaceae) and Babesia (Piroplasmida: Babesiidae) species. Of 4737 ticks [predominantly Ixodes ricinus Linneaus (Ixodida: Ixodidae)], B. burgdorferi s.l. was detected in 94 (2.0%). Four Borrelia genospecies were identified: Borrelia garinii (41.5%); Borrelia afzelli (31.9%); Borrelia burgdorferi sensu stricto (25.5%), and Borrelia spielmanii (1.1%). One Rhipicephalus sanguineus Latreille (Ixodida: Ixodidae), collected from a dog with a history of travel outside the U.K., was positive for B. garinii. Seventy ticks (1.5%) were positive for Babesia spp. Of these, 84.3% were positive for Babesia venatorum, 10.0% for Babesia vulpes sp. nov., 2.9% for Babesia divergens/Babesia capreoli and 1.4% for Babesia microti. One isolate of Babesia canis was detected in a Dermacentor reticulatus (Ixodida: Ixodidae) tick collected from a dog that had recently travelled to France. Prevalences of B. burgdorferi s.l. and Babesia spp. did not differ significantly between different regions of the U.K. The results map the widespread distribution of B. burgdorferi s.l. and Babesia spp. in ticks in the U.K. and highlight the potential for the introduction and establishment of exotic ticks and tick‐borne pathogens.     

The cell-mediated immune response to Borrelia afzelii, garinii and burgdorferi in C57BL/6 mice is dependent on antigen specificity

Inbred C57BL/6 mice were challenged with Borrelia afzelii, Borrelia garinii and Borrelia burgdorferi sensu stricto and tested for antigen-specific T-cell response in vitro. The sonicated preparations of in vitro grown spirochetes were capable of stimulating polyclonal proliferation and specific cell-mediated response, depending on duration of the cell culture. Murine splenocytes previously sensitized to B. burgdorferi sensu lato (s.l. ), but not those from control mice, could be induced for antigen-specific proliferation in vitro. Moreover, detectable cell-mediated response could be induced only with antigen preparations derived from a corresponding strain but not with those obtained from other Borrelia genospecies as revealed by the [(3)H]thymidine incorporation assay. The current study considers that the strict B. burgdorferi s.l. antigen-specific response may also be expected in infections in humans and contributes to the explanation of the frequently poor antibody- and cell-mediated immune response observed in patients diagnosed with Lyme disease.     

Identification of four genomic groups ofBorrelia burgdorferi sensu lato inIxodes ricinus ticks collected in a Lyme borreliosis endemic region of northern Croatia

We investigated the presence ofBorrelia burgdorferi sensu lato inIxodes ricinus ticks collected in a Lyme borreliosis (LB) endemic region of northern Croatia. Ticks (n=124) were collected at five locations and analysed by the polymerase chain reaction (PCR). A DNA fragment from the internal transcribed spacer (ITS2) ofI. ricinus was detected in all tick lysates, indicating that PCR inhibitors were not present.Borrelia burgdorferi sensu lato DNA was detected in 56 out of 124 ticks (45%). Four genomic groups were identified:Borrelia afzelii (n=26),Borrelia garinii (n=5), group VS116 (n=5) andB. burgdorferi sensu stricto (n=1). Mixed infections ofB. afzelii with group VS116 (n=10) andB. afzelii withB. burgdorferi sensu stricto (n=1) were also detected. Eight ticks containedB. burgdorferi sensu lato, which could not be typed. The detection ofB. afzelii andB. garinii in ticks was in agreement with manifestations of LB found locally. The occurrence of group VS116 in northern Croatia and in an earlier study in The Netherlands, infers that this genomic group may be well established in EuropeanI. ricinus.     

Tick borne zoonosis: selected clinical and diagnostic aspects

Tick-borne zoonotic infections are among the most diffuse vector borne diseases: these large group of infections is caused by different microorganisms: Babesia spp., Borrelia spp., Rickettsia spp., Ehrlichia spp., Francisella tularensis, Coxiella burnetii) and tick-borne encephalitis virus. Babesiosis is caused by the protozoa (sporozoa) Babesia microti and it is quite rare in humans in Europe. The ixodids ticks are the competent vectors. A few symptomatic cases have been reported, mainly in splenectomized patients. The laboratory diagnosis is made by the microscopic identification of the parasites within the red blood cells in blood smears. The serologic diagnosis, based mainly upon IFA and WB techniques has only an epidemiological interest. Lyme borreliosis (Lyme disease) has been recognized as the most frequent vector borne disease in mild climate areas. The etiologic agent is a spirochete, belonging to the Borrelia burgdorferi sensu lato complex: B. burgdorferi sensu stricto, B. garinii and B. afzelii. Several additional species of this geno-complex have been identified but their pathogenic capability for humans still needs to be elucidated. Lyme borreliosis is clinically divided into three different clinical stages: the early disease, the disseminated infection and the persistent infection. Individual stages are caused by the diffusion of the spirochetes to different anatomic districts of the body. The main clinical symptoms are, for each stage: the erythema chronicum migrans in the early infection, the peripheral nerves and joint involvement in disseminated diseases and the acrodermatitis chronica atrophica (ACA) with central nervous system involvement in the late disseminated infection. The microbiological diagnosis is achieved by serologic techniques (IFA, EIA, WB) and by isolation of the spirochetes (in vitro culture and DNA amplification methods). Tick-borne relapsing fever (TBRF) is occasionally transmitted to humans by the soft ticks Ornithodorus and is caused by Borrelia spp. Different borreliae are responsible for TBRF in various geographic areas. The laboratory diagnosis is based upon the identification of spirochetes in peripheral blood by microscopic observation of Giemsa stained smears. Rickettsiosis diseases are caused worldwide by the obligate intracellular bacteria belonging to the genus Rickettsia. In the Mediterranean area the most frequently identified rickettsia is R. conorii, that causes the so called Mediterranean spotted fever. The serologic detection of a specific antibody response by IFA techniques is the most prominent tool for the diagnosis. In addition, the PCR method can be applied. Bacteria of the genus Ehrlichia are well known pathogens in veterinary medicine. Since the last decade their zoonotic capability has emerged and E. chafeensis, E. canis and the so called human granulocytic agent (HGE) have been identified in human diseases following a tick bite. The ehrlichiosis is characterized, in human, by a mild fever associated with lymphoadenopathy. The diagnosis is made on the identification of morulae (the intracytoplasmatic inclusion of the growing rickettsiae) in the white cells of peripheral blood. In addition the molecular diagnosis is also possible by PCR. Tick-borne encephalitis (TBE) is the only viral arthropod-borne encephalitis in Europe: it is caused by a flavivirus and it can also be transmitted by the ingestion of goat raw milk. The more relevant epidemiological figure is limited to the Alps, in particular to the Northern side (Austria). Isolated cases have been reported also in Italy. TBE is a benign self-limiting illness that usually recovers without any reliquate. The laboratory diagnosis is obtained by isolating the virus in cell cultures from the CSF or blood of acute phase patients. Serology is anyway the main laboratory tool to perform this diagnosis. Complement fixation and EIA IgM are the most used methods: the latter technique is particularly sensitive in early infection.     

Controlled activation of the Cpx system is essential for growth of Yersinia enterocolitica

Until recently, three spirochete genospecies were considered to be the causative agents of Lyme borreliosis (LB) in Europe: Borrelia burgdorferi sensu stricto, Borrelia afzelii and Borrelia garinii . However, the DNA of Borrelia valaisiana, Borrelia lusitaniae, Borrelia spielmanii and Borrelia bissettii has already been detected in samples of human origin, or the spirochetes were isolated from the patients with symptoms of LB. Molecular analysis of 12 selected serum samples collected in the regional hospital confirmed the presence of B. bissettii DNA in cases of single and multiple infection in patients with symptomatic borreliosis or chronic borrelial infection. The presence of B. bissettii as a single strain in patients provides strong support of the fact that B. bissettii might be a causative agent of the disease. After the first isolation of B. bissettii from the samples of human origin in Slovenia, following the detection of this species in cardiac valve tissue of the patient with endocarditis and aortic valve stenosis in the Czech Republic, here we present additional molecular data supporting the involvement of B. bissettii in LB in Europe.     

Longitudinal analysis of tick densities and Borrelia, Anaplasma, and Ehrlichia infections of Ixodes ricinus ticks in different habitat areas in The Netherlands

From 2000 to 2004, ticks were collected by dragging a blanket in four habitat areas in The Netherlands: dunes, heather, forest, and a city park. Tick densities were calculated, and infection with Borrelia burgdorferi and Anaplasma and Ehrlichia species was investigated by reverse line blot analysis. The lowest tick density was observed in the heather area (1 to 8/100 m2). In the oak forest and city park, the tick densities ranged from 26 to 45/100 m2. The highest tick density was found in the dune area (139 to 551/100 m2). The infection rates varied significantly for the four study areas and years, ranging from 0.8 to 11. 5% for Borrelia spp. and 1 to 16% for Ehrlichia or Anaplasma (Ehrlichia/Anaplasma) spp. Borrelia infection rates were highest in the dunes, followed by the forest, the city park, and heather area. In contrast, Ehrlichia/Anaplasma was found most often in the forest and less often in the city park. The following Borrelia species were found: Borrelia sensu lato strains not identified to the species level (2.5%), B. afzelii (2.5%), B. valaisiana (0.9%), B. burgdorferi sensu stricto (0.13%), and B. garinii (0.13%). For Ehrlichia/Anaplasma species, Ehrlichia and Anaplasma spp. not identified to the species level (2.5%), Anaplasma schotti variant (3.5%), Anaplasma phagocytophilum variant (0.3%), and Ehrlichia canis (0.19%) were found. E. canis is reported for the first time in ticks in The Netherlands in this study. Borrelia lusitaniae, Ehrlichia chaffeensis, and the human granylocytic anaplasmosis agent were not detected. About 1.6% of the ticks were infected with both Borrelia and Ehrlichia/Anaplasma, which was higher than the frequency predicted from the individual infection rates, suggesting hosts with multiple infections or a possible selective advantage of coinfection.     

Inhibition of fibroblast apoptosis by Borrelia afzelii, Coxiella burnetii and Bartonella henselae

Apoptosis is a genetically controlled mechanism of cell death involved in the regulation of tissue homeostasis. The aim of this study was to investigate the influence of Borrelia afzelii, Coxiella burnetii, and Bartonella henselae bacteria on apoptosis measured as the level of caspase 3 activity in human fibroblast cells HEL-299. Our findings show that C. burnetii bacteria may inhibit the process of apoptosis in the host cells for a long time. This can permit intracellular survival in the host and mediatingthe development of chronic disease.     

Methylated DNA in Borrelia species.

The DNA of Borrelia species was examined for the presence of methylated GATC sequences. The relapsing-fever Borrelia sp., B. coriaceae, and only 3 of 22 strains of B. burgdorferi contained adenine methylation systems. B. anserina lacked an adenine methylation system. Fundamental differences in DNA methylation exist among members of the genus Borrelia.     

Borrelia burgdorferi sensu lato detected in skin of Norwegian mountain hares (Lepus timidus) without signs of dissemination

The mountain hare (Lepus timidus) population in southern Norway appears to be in decline. Necropsy and laboratory examinations of 36 hares found dead or diseased during 2007-2009 in Vest- and Aust-Agder counties showed that disease and deaths were attributed to multiple causes, with no specific etiology emerging as a cause for population decline. To investigate whether Borrelia burgdorferi sensu lato (s.l.) infection is associated with mortality in mountain hares, tissues and ticks collected from hares were investigated for infection with the spirochete. Borrelia burgdorferi s.l. DNA was not detected in samples from internal organs, whereas Borrelia afzelii, B. burgdorferi sensu stricto (s.s.), and the not-yet-defined Borrelia sp. SV1 were found in skin samples from hares and in adult and nymphal Ixodes ricinus feeding on hares. Only B. burgdorferi s.s. and Borrelia sp. SV1 were detected in larvae feeding on hares. Our results indicate that disseminated Borrelia infection in hares rarely occurs and, presumably, does not play a central role in the suspected population decline. The results also suggest that the mountain hare to some degree functions as a transmission host for B. burgdorferi s.s. and Borrelia sp. SV1.     

The presence of Borrelia valaisiana-related genospecies in ticks and a rodent in Taiwan

A field survey was conducted to investigate the presence of Borrelia burgdorferi sensu lato (s.l.) in six counties of Taiwan. Spirochetes were successfully isolated from one rodent ear sample out of 485 rodent ears and 53 live, fed tick (Ixodes granulatus) samples. The spirochetes were confirmed to be B. burgdorferi s.l. by real-time PCR. In addition, 23 of 113 tick samples were tested positive for Borrelia DNA according to real-time PCR. The Borrelia isolate from the rodent and the 23 Borrelia DNA samples from the ticks were identified as B. valaisiana-related genospecies by phylogenetic analysis based on flagellin gene sequences. These findings suggest that the Borrelia valaisiana-related strains are maintained in a zoonotic cycle between tick vectors and reservoir hosts in Taiwan.     

Tick-borne bacteria in mouflons and their ectoparasites in Cyprus

The Cypriot mouflon (Ovis orientalis ophion), a once almost extirpated species of wild sheep, is under strict surveillance because it can be threatened by likely transmission of pathogenic bacteria, such as Anaplasma spp., Rickettsia spp., and Coxiella burnetii, primarily from domestic ungulates. We collected 77 blood samples from Cypriot mouflons and 663 of their ectoparasites (Rhipicephalus turanicus, Rhipicephalus sanguineus, Rhipicephalus bursa, Hyalomma anatolicum excavatum, Hyalomma marginatum, Haemaphysalis punctata, Haemaphysalis sulcata, and Ixodes gibossus) and tested them by polymerase chain reaction and sequencing. Twenty-three mouflon blood samples (30%) were positive for C. burnetii, 23 (30%) for Rickettsia spp., and 8 (10%) for Anaplasma ovis. Of 109 pools of ectoparasites, 32.1% were positive for C. burnetii, 28.4% for Rickettsia spp., and 10.9% for A. ovis; 11.9% were positive for both C. burnetii and Rickettsia spp., 6.4% for both Rickettsia spp. and A. ovis, and 2.8% for all three pathogens. This is the first survey that records the presence of tick-borne pathogens, both in the Cypriot mouflon and in ticks parasitizing it.     

Hidden in plain sight: Borrelia burgdorferi and the extracellular matrix

Borrelia burgdorferi, the tick-transmitted etiologic agent of Lyme borreliosis, can colonize and persist in multiple tissue sites despite vigorous host immune responses. The extracellular matrix appears to provide a protective niche for the spirochete. Recent studies in mice suggest that B. burgdorferi interacts in various ways with collagen and its associated molecules, exploiting molecular and structural features to establish microcolonial refugia. Better knowledge of the genetic and structural bases for these interactions of B. burgdorferi with the extracellular matrix will be required before an understanding of the persistence of B. burgdorferi in the tissues and development of chronic infections can be achieved.     

Antibodies to Rickettsia rickettsii, Rickettsia typhi, Coxiella burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis among healthy population in Minas Gerais, Brazil

Rickettsial diseases except those belonging to spotted fever group rickettsioses are poorly studied in South America particularly in Brazil where few epidemiological reports have been published. We describe a serosurvey for Rickettsia rickettsii, R. typhi, Coxiella burnetii, Bartonella henselae, B. quintana, and Ehrlichia chaffeensis in 437 healthy people from a Brazilian rural community. The serum samples were tested by indirected micro-immunoflourescence technique and a cutoff titer of 1:64 was used. The seroprevalence rates for R. rickettsii, R. typhi, C. burnetii, B. henselae, B. quintana, and E. chaffeensis were respectively 1.6% (7 samples); 1.1% (5 samples); 3.9% (17 samples); 13.7% (60 samples); 12.8% (56 samples), and 10.5% (46 samples). Frequent multiple/cross-reactivity was observed in this study. Age over 40 years old, urban profession, and rural residence were significantly associated with some but not all infections rate. Low seropositivity rates for R. rickettsii, R. typhi, and C. burnetii contrasted with higher rates of seropositivity for B. quintana, B. henselae, and E. chaffeensis. These results show that all tested rickettsial species or antigenically closely related possible exist in this particular region.