Novel Anaplasmataceae agents Candidatus Ehrlichia hydrochoerus and Anaplasma spp. Infecting Capybaras, Brazil.

We amplified Ehrlichia and Anaplasma DNA from Amblyomma dubitatum tick-infested capybaras (Hydrochoerus hydrochaeris) in southern Brazil. Sequencing of 16S rRNA, sodB, and groEL indicated a novel Ehrlichia species, and sequencing of 16S rRNA from 2 capybaras indicated a novel Anaplasma species. The tick vectors remain unknown.

Seroprevalence of Rickettsia spp. in Equids and Molecular Detection of 'Candidatus Rickettsia amblyommii' in Amblyomma cajennense Sensu Lato Ticks From the Pantanal Region of Mato Grosso, Brazil.

The aim of the study was to evaluate exposure of equids to rickettsial agents (Rickettsia rickettsii, Rickettsia parkeri, 'Candidatus Rickettsia amblyommii', Rickettsia rhipicephali, and Rickettsia bellii) and rickettsial infection in ticks of a Pantanal region of Brazil. Sera of 547 equids (500 horses and 47 donkeys) were evaluated by indirect immunofluorescence assay. In total, 665 adults and 106 nymphal pools of Amblyomma cajennense F. sensu lato, 10 Dermacentor nitens Neumann ticks, and 88 larval pools of Amblyomma sp. were tested by polymerase chain reaction (PCR). Overall, 337 (61.6%) equids were reactive (titer ≥64) to at least one antigen of Rickettsia spp. The prevalence values for Rickettsia were 66%, and the highest endpoint titers were observed for 'Ca. R. amblyommii'. By PCR 3 (0.45%) A. cajennense s.l. females were positive for 'Ca. R. amblyommii'. Minimum infection rates of 0.75% for nymphs and 0.34% for larvae were calculated. Positive samples of ticks have had a fragment of the 16S mitochondrial rRNA gene sequenced and sequences showed 99% identity to Amblyomma sculptum Berlese. This study reports a wide exposure of equids to Rickettsia agents, and PCR evidence of infection with 'Ca. R. amblyommii', for the first time, in A. sculptum.

Correlation between canine biochemical analytes and TRP36 ELISA seropositivity for Ehrlichia canis in Brazil.

BACKGROUND: Synthetic peptides of tandem repeat proteins (TRPs) have been employed in the serologic analysis of canine monocytic ehrlichiosis (CME) and used in epidemiological studies in Brazil. Based on molecular studies of TRPs, different genotypes of Ehrlichia canis have been described, but data on their pathogenicity remain unknown. OBJECTIVES: To correlate hepatic, renal, and muscular alterations in relation to different genotypes of E. canis in naturally exposed dogs using enzyme-linked immunosorbent assay (ELISA) with TRP19 and TRP36 synthetic protein antigens. METHODS: Two hundred serum samples were subjected to ELISA with the antigens of TRP19 and three genotypes (US, Br, and CR) of TRP36 of E. canis circulating in Brazil. Positive sera were evaluated through eight biochemical parameters, and the results were evaluated by principal component analysis and canonical correlation. RESULTS: ELISA revealed that 47 (23.5%) serum samples reacted to the BrTRP36 peptide, 36 (18%) reacted to the TRP19 peptide, and 8 (4%) reacted to the USTRP36 and CRTRP36 peptides separately. The most frequent biochemical alterations observed were for CK (59.4%), ALB (31.8%), GLO (28.9%), TP (28.9%), ALP (26%), urea (24.6%), creatinine (14.4%), and ALT (14.4%). The most prominent diagnostic method in canonical correlation analysis was BrTRP36, followed by TRP19, which correlated with hyperglobulinemia and hypoalbuminemia. CONCLUSIONS: Antibodies that reacted against the Brazilian genotype of E. canis correlated positively with hyperglobulinemia and increases in serum urea and creatinine. According to our results, the Brazilian genotype of E. canis is related to the chronic phase of CME.

First molecular detection of Mycoplasma ovis in horses from Brazil.

This study aimed to determine the occurrence of hemoplasmas and tick-borne pathogens (TBP) (Theileria equi, Babesia caballi, and Ehrlichia sp.) in horses and ticks' salivary glands, and determine the factors associated with exposure/infection in a rural settlement in southern Brazil. Blood samples from 22 horses were screened for anti-T. equi and anti-Ehrlichia sp. antibodies by an indirect fluorescent antibody test (IFAT) assays. Samples were also tested by PCR assays for T. equi and B. caballi (18S rRNA and rap-1 genes, respectively), hemoplasmas (16S rRNA gene), and Ehrlichia sp. (dsb gene). Ticks were removed from the animals (inspection) and the environment (flannel trawling and dry ice traps), and morphologically identified. Additionally, salivary glands DNA was extracted from 28 adult ticks infesting the animals and four nymphs from the environment, and further screened for Ehrlichia sp. and hemotropic Mycoplasma sp. Anti-T. equi and anti-Ehrlichia sp. antibodies were detected in 40.91% (nine/22; 95% CI: 23.26-61.27) and 31.81% (seven/22; 95% CI: 16.36-52.68) horses, respectively. Theileria equi, B. caballi, and hemotropic Mycoplasma sp. DNA was detected in 59.09% (13/22), 4.55% (one/22), and 50% (11/22) horses, respectively. All horses tested negative in the PCR for Ehrlichia sp. All sequences showed ≥99% identity with multiple T. equi, B. caballi, and Mycoplasma ovis sequences deposited in GenBank database. Adult ticks were identified as Dermacentor nitens (44/47; 93.62%) and Rhipicephalus microplus (three/47; 6.38%). Ticks' salivary glands were negative for Ehrlichia sp., while 39.29% from adults (11/28) and 50% from nymphs (two/four) from the environment were positive for hemotropic Mycoplasma sp. This is the first report of M. ovis infection in horses from Brazil and the first detection of hemoplasma DNA in salivary glands of D. nitens and R. microplus ticks. Further studies are needed to elucidate the vector competence of ticks to transmit hemoplasmas.

Diversity and prevalence of intestinal parasites of zoonotic potential in animal hosts from different biomes in the central region of Brazil.

The Brazilian state of Mato Grosso comprises the biomes Cerrado, Pantanal, and Amazon rainforest. The animals that make up the biodiversity of these biomes have an ongoing relationship with domestic animals. This study aimed to describe the prevalence and diversity of intestinal parasites in different class of animal hosts, domestic and wild, from the three biomes of Brazil's central region, during 2019. We analyzed animal faecal samples by sedimentation tests and centrifugal flotation in sucrose. The Shannon index test to calculate diversity and equitability, was used. In the 280 samples analyzed, 79.64% was positive. Domestic animals showed positivity of 87% and wild animals of 51%, being mammals the most prevalent, with 81%. Blastocystis sp. was the most prevalent protozoan, and Ascaris sp. of the helminths. Shannon's indexes were higher for the Pantanal. Overall, pigs, cows, and chickens had high prevalence values and diversity and equitability of enteroparasites. Due to the great diversity of parasites found in pigs, cows and chickens, these animals can play an important role in the transmission and maintenance of the infection to other mammals, including humans.

First Evidence of Ehrlichia minasensis Infection in Horses from Brazil.

The genus Ehrlichia includes tick-borne bacterial pathogens affecting humans, domestic and wild mammals. Ehrlichia minasensis has been identified in different animal species and geographical locations, suggesting that this is a widely distributed and generalist Ehrlichia. In the present study, we evaluated Ehrlichial infection in 148 Equidae presented to the Medical Clinic Department of a Veterinary Hospital from a midwestern region of Brazil. Blood samples and ticks collected from the animals were tested by Polymerase Chain Reaction (PCR) for the presence of Ehrlichia spp. A multigenic approach including Anaplasmataceae-specific (i.e., 16S rRNA, groEL, gltA) and Ehrlichia-specific (i.e., dsb and trp36) genes was used for accurate bacteria identification. Sera samples were also collected and evaluated for the detection of anti-Ehrlichia antibodies by indirect fluorescent antibody test (IFA). Possible associations between molecular and serological diagnostics and clinical and hematological manifestations were tested using chi-squared or Fisher's exact tests. Sequence analysis of the dsb fragment revealed that three horses (2.03%) were exposed to E. minasensis. Sixty-one (41.2%) Equidae (58 equines and three mules), were seropositive for Ehrlichia spp., with antibody titers ranging between 40 and 2560. Seropositivity to ehrlichial antigens was statistically associated with tick infestation, rural origin, hypoalbuminemia and hyperproteinemia (p ≤ 0.05). The present study reports the first evidence of natural infection by E. minasensis in horses from Brazil.

Morphometric Patterns and Blood Biochemistry of Capybaras (Hydrochoerus hydrochaeris) from Human-Modified Landscapes and Natural Landscapes in Brazil.

The capybara, Hydrochoerus hydrochaeris, is the largest extant rodent of the world. To better understand the correlation between size and body mass, and biochemical parameters of capybaras from areas with different degrees of anthropization (i.e., different food supplies), we sampled free-ranging capybaras from areas of natural landscapes (NLs) and human-modified landscapes (HMLs) in Brazil. Analyses of biometrical and biochemical parameters of capybaras showed that animals from HMLs were heavier (higher body mass) than those from NL, a condition possibly related to fat deposit rather than body length, as indicated by Body Condition Index (BCI) analyses. Biochemical parameters indicated higher serum levels of albumin, creatine kinase, cholesterol, fructosamine and total protein among capybaras from HMLs than from NLs; however, when all adult capybaras were analyzed together only cholesterol and triglycerides were positively correlated with body mass. We propose that the biochemical profile differences between HMLs and NLs are related to the obesity condition of capybaras among HMLs. Considering that heavier animals might live longer and reproduce more often, our results could have important implications in the population dynamics of capybaras among HMLs, where this rodent species is frequently represented by overgrowth populations that generate several levels of conflicts with human beings.

Small mammals, ticks and rickettsiae in natural and human-modified landscapes: Diversity and occurrence of Brazilian spotted fever in Brazil.

We studied communities of small mammals and their ticks in endemic (E) and non-endemic (NE) areas for Brazilian spotted fever (BSF), aiming to infer if diversity parameters of parasites and hosts could be related to occurrence and prevalence of rickettsial infection, especially Rickettsia rickettsii. We compared E and NE areas in human-modified landscapes (HMLs) and natural areas (BIO) with no report of BSF cases. Composition and equitability were important components of diversity explaining differences among areas. The marsupial Didelphis albiventris was dominant in HMLs, but not in natural areas, and this opossum was the main host for the tick Amblyomma sculptum, principal vector of R. rickettsii, especially in E areas. Communities of ticks were dominated by A. sculptum, followed by Amblyomma dubitatum in E areas. In NE areas, this dominance was inverted, with more A. dubitatum than A. sculptum infesting small mammals, but the numbers of ticks were much lower than in E areas. Composition and abundance of ticks in natural areas were very dissimilar from HMLs, with the lowest tick burdens. Didelphis albiventris in E areas presented higher seroprevalence and endpoint titres against R. rickettsii than in other areas. At least three Rickettsia species, non-pathogenic to humans, were detected in natural areas (Rickettsia bellii, Rickettsia amblyommatis and 'Candidatus Rickettsia andeanae'), and only one non-pathogenic species in HMLs (R. bellii). Our results suggest that higher diversity of ticks, hosts and rickettsiae could be relevant factors in buffering the effect in BSF occurrence. Particularly for D. albiventris, its importance has to be quantified in further studies considering the epidemiological scenario of BSF.

Canonical correlative analyses among an enzyme-linked immunosorbent assay using synthetic peptides, an indirect fluorescent antibody test, and hematologic measurements in dogs infected with Ehrlichia canis.

BACKGROUND: Immunoreactive tandem repeat proteins (TRPs) in amino acid sequences were identified and employed in the serologic diagnosis of canine monocytic ehrlichiosis (CME). OBJECTIVES: This study evaluated using TRP19 and TRP36 synthetic protein antigens with enzyme-linked immunosorbent assays (ELISAs) and compared the results with an indirect fluorescent antibody test (IFAT) to diagnose CME in the serum of dogs with suspected CME. METHODS: The sera of 243 dogs that exhibited clinical and hematologic signs suggestive of CME had IFATs performed. An ELISA with synthetic TRP19 and TRP36 antigens from two E canis genotypes (USTRP36 and BrTRP36) that circulate in Brazil were also performed. Canonical correlations and chi-square tests were evaluated on the results of these tests. RESULTS: Among the 243 dogs, 179 (73.6%) were reactive at an IFAT ≥ 40, 167 (68.72%) reacted at the cut-off ≥160, and 149 (61.31%) reacted at ≥640. The ELISA revealed that 172 (70.8%) dogs reacted to TRP19 peptide, 163 (67.1%) reacted to USTRP36, and 114 (46.9%) reacted to BrTRP36. The canonical correlation analyses showed that the TRP19 ELISA was the most effective diagnostic method. Serum total protein levels showed strong positive correlations with the USTRP36 peptide. Qualitative analyses revealed an association between the TRP19 peptide and the presence of anemia, thrombocytopenia, and hyperproteinemia. The IFAT results at titers of ≥160 and ≥640 were associated with thrombocytopenia. CONCLUSIONS: The results of this study indicated that the TRP19 peptide was an excellent antigen and that the IFAT was diagnostically important in confirming the diagnosis of CME in serum samples.

Habitat selection in natural and human-modified landscapes by capybaras (Hydrochoerus hydrochaeris), an important host for Amblyomma sculptum ticks.

Human activities are changing landscape structure and function globally, affecting wildlife space use, and ultimately increasing human-wildlife conflicts and zoonotic disease spread. Capybaras (Hydrochoerus hydrochaeris) are linked to conflicts in human-modified landscapes (e.g. crop damage, vehicle collision), as well as the spread and amplification of Brazilian spotted fever (BSF), the most human-lethal tick-borne disease in the world. Even though it is essential to understand the link between capybaras, ticks and BSF, many knowledge gaps still exist regarding the effects of human disturbance in capybara space use. Here, we analyzed diurnal and nocturnal habitat selection strategies of capybaras across natural and human-modified landscapes using resource selection functions (RSF). Selection for forested habitats was higher across human-modified landscapes, mainly during day- periods, when compared to natural landscapes. Across natural landscapes, capybaras avoided forests during both day- and night periods. Water was consistently selected across both landscapes, during day- and nighttime. Distance to water was also the most important variable in predicting capybara habitat selection across natural landscapes. Capybaras showed slightly higher preferences for areas near grasses/shrubs across natural landscapes, and distance to grasses/shrubs was the most important variable in predicting capybara habitat selection across human-modified landscapes. Our results demonstrate human-driven variation in habitat selection strategies by capybaras. This behavioral adjustment across human-modified landscapes may be related to increases in A. sculptum density, ultimately affecting BSF.

First report of a canine morbillivirus infection in a giant anteater (Myrmecophaga tridactyla) in Brazil.

Canine morbillivirus, also known as canine distemper virus (CDV), induces a contagious multisystemic disease caused by an enveloped RNA virus belonging to the genus Morbillivirus within the family Paramyxoviridae. CDV replicates readily in epithelial, nerve and lymphoid tissues; it is excreted in urine, feces, saliva, oral and nasal discharge; and its major route of entry for infection is through the respiratory system. Although the virus was originally believed to infect domestic dogs, new studies have shown that it can also naturally or experimentally infect non-domestic hosts. A recent blood test performed on a giant anteater (Myrmecophaga tridactyla) found Lentz inclusions in the animal's leucocytes. A rapid CDV test, an RT-PCR assay and pathology findings confirmed this report of canine morbillivirus in this species, which corresponds to the second report of CDV infection in the order Pilosa, family Myrmecophagidae in central west Brazil.

Complete Genome Sequence of an Ehrlichia minasensis Strain Isolated from Cattle.

Ehrlichia minasensis is a tick-borne pathogen affecting cattle, cervids, and dogs, and it is closely related to the monocytotropic pathogen Ehrlichia canis Here, we announce the draft genome sequence of Ehrlichia minasensis strain Cuiabá, isolated from a naturally infected calf from Santo Antônio do Leverger, Mato Grosso, Brazil.

Tick-borne pathogens in carthorses from Foz do Iguaçu City, Paraná State, southern Brazil: A tri-border area of Brazil, Paraguay and Argentina.

Tick-borne diseases (TBD) constitute an important group of illness affecting animals and humans worldwide. In Brazil, carthorses are frequently exposed to ticks and tick-borne pathogens, leading to impairment of horse performance and imposing restrictions by the international veterinary authorities for the importation of horses. Accordingly, this study has aimed to i) determine the prevalence of the TBD agents Theileria equi, Babesia caballi, Ehrlichia spp., and hemotropic mycoplasmas in carthorses, ii) identify the tick species parasitizing the animals, and iii) determine factors associated with exposure/infection in Foz do Iguaçu City, Parana state, southern Brazil. A total of 103 carthorses were screened for anti-T. equi and anti-Ehrlichia spp. antibodies by indirect fluorescent antibody assays (IFA). Samples were also tested by PCR assays targeting the 18S rRNA gene of T. equi and B. caballi, and 16S rRNA gene of hemoplasmas. Additionally, PCR assays targeting the 16S rRNA, disulfide bond formation protein (dsb) and tandem repeat proteins 36 (trp36) genes of Ehrlichia spp. were also performed. Antibodies to T. equi and Ehrlichia spp. were detected in 43/103 (41.75%; 95% CI: 32.10-51.88%) and 5/103 (4.85%; 95% CI: 1.59-10.97%) horses by IFA, respectively. DNA of T. equi and B. caballi were found in 25/103 (24.27%; 95% CI: 16.36-33.71%) and 10/103 (9.71%; 95% CI: 4.75-17.13%) carthorses, respectively, and all tested negative for Ehrlichia spp. and hemoplasmas. All sequences showed ≥99% identity with multiple T. equi and B. caballi 18S rRNA gene sequences deposited in GenBank. Overall, 191 Dermacentor nitens ticks were collected from 25/103 (24.27%) animals. Carthorses older than 5 years were more likely to be positive for T. equi (p < 0.05). In conclusion, equine piroplasmosis agents are highly prevalent in carthorses from Foz do Iguaçu City. The low prevalence of Ehrlichia spp. found may be due to the absence of Amblyomma ticks infesting animals, which should be further investigated.

Divergent coronaviruses detected in wild birds in Brazil, including a central park in São Paulo.

Coronaviruses are single-stranded positive-sense RNA viruses associated with important avian diseases. Their relatively high rates of mutation and recombination frequencies allow them to adapt to new hosts and ecological niches. Although Brazil has 18% of global avian species diversity, studies regarding the presence of avian viral diseases in wild birds in South America are scarce. In this study, we performed a retrospective analysis of the presence of CoVs in 746 wild birds. Oropharyngeal and cloacal swabs were obtained and placed together in vials containing VTM transport medium collected in different regions of Brazil between 2006 and 2013. Screening for viral nucleic acid was performed using conventional RT-PCR and pancoronavirus nested PCR. Positive samples were characterized by partial sequencing of the RNA-dependent RNA polymerase (RdRp) gene, and ensuing phylogenetic analysis was performed to investigate the association between virus epidemiology and bird migration routes. Coronavirus RNA were detected and sequenced from six samples, in which three were related to gammacoronaviruses group and the other three to deltacoronavirus group. Our study documents the presence of CoVs related to avian gamma- and deltacoronaviruses circulating in both urban- and poultry-farm regions of Brazil, implicating wild birds as potential carriers of CoVs which may represent a risk to poultry farms and public health in Brazil.

Epidemiology of capybara-associated Brazilian spotted fever.

BACKGROUND: Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, has been associated with the transmission by the tick Amblyomma sculptum, and one of its main hosts, the capybara (Hydrochoerus hydrochaeris). METHODS: During 2015-2019, we captured capybaras and ticks in seven highly anthropic areas of São Paulo state (three endemic and four nonendemic for BSF) and in two natural areas of the Pantanal biome, all with established populations of capybaras. RESULTS: The BSF-endemic areas were characterized by much higher tick burdens on both capybaras and in the environment, when compared to the BSF-nonendemic areas. Only two tick species (A. sculptum and Amblyomma dubitatum) were found in the anthropic areas; however, with a great predominance of A. sculptum (≈90% of all ticks) in the endemic areas, in contrast to a slight predominance of A. dubitatum (≈60%) in the nonendemic areas. Tick species richness was higher in the natural areas, where six species were found, albeit with a predominance of A. sculptum (≈95% of all ticks) and environmental tick burdens much lower than in the anthropic areas. The BSF-endemic areas were characterized by overgrowth populations of A. sculptum that were sustained chiefly by capybaras, and decreased populations of A. dubitatum. In contrast, the BSF-nonendemic areas with landscape similar to the endemic areas differed by having lower tick burdens and a slight predominance of A. dubitatum over A.sculptum, both sustained chiefly by capybaras. While multiple medium- to large-sized mammals have been incriminated as important hosts for A. sculptum in the natural areas, the capybara was the only important host for this tick in the anthropic areas. CONCLUSIONS: The uneven distribution of R. rickettsii infection among A. sculptum populations in highly anthropic areas of São Paulo state could be related to the tick population size and its proportion to sympatric A. dubitatum populations.

Isolation of Toxoplasma gondii from capybaras (Hydrochaeris hydrochaeris) from São Paulo State, Brazil.

The capybara (Hydrochaeris hydrochaeris) is a large rodent used for human consumption in certain areas of South America. In the present study, viable Toxoplasma gondii was isolated for the first time from this host. Antibodies to T. gondii were assayed in the sera of 64 capybaras from 6 counties of São Paulo State, Brazil, using the modified agglutination test (MAT, > or =1:25 dilution) and the indirect fluorescent antibody test (IFAT, > or =1:16 dilution), and antibodies were found in 48 (75%) by MAT, and 49 (76.6%) by IFAT. Samples of brain, heart, and tongue of 40 seropositive capybaras were pooled, digested in pepsin, and bioassayed in mice. Toxoplasma gondii was isolated from tissue homogenates of 36 capybaras, and the isolates were designated TgCyBrl-36. Most isolates were lethal to mice; 17 of the 36 isolates killed 100% of infected mice, 11 isolates caused mortality in 25-90% of infected mice, and 8 isolates were nonpathogenic to mice. Results indicate that asymptomatic capybaras can harbor mouse-virulent T. gondii, and hence they can serve as a source of infection for humans.

In vitro isolation and molecular characterization of an Ehrlichia canis strain from São Paulo, Brazil.

An Ehrlichia canis isolate was obtained from an naturally infected dog exhibiting clinical signs of ehrlichiosis in São Paulo Municipality, state of São Paulo, Brazil. The isolate was characterized by PCR and DNA sequencing of portions of the ehrlichial genes dsb, 16SrRNA, and p28. Partial dsb and 16S rRNA sequences were identical to three and five other E. canis strains, respectively, from different countries and continents (including North America, Africa, Asia and Europe). Conversely, the p28 partial sequence for this E. canis (São Paulo) differed by 1, 2, and 2 nucleotides from the corresponding sequences of the E. canis strains Jake (from USA), Oklahoma (USA), and VHE (Venezuela), respectively. The results in this study indicate that E. canis is the only recognized Ehrlichia species infecting dogs in Brazil.

Prevalence of Rickettsia infection in dogs from the urban and rural areas of Monte Negro municipality, western Amazon, Brazil.

The present study evaluated the rickettsial infection among dogs living in the rural and urban areas of Monte Negro, state of Rondônia, western Brazilian Amazon. Canine sera were tested by the indirect immunofluorescence assay (IFA) using six rickettsial antigens: Rickettsia bellii, Rickettsia amblyommii, Rickettsia rhipicephali, Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia felis. While the first three Rickettsia species are known to occur in the study site, the latter three species are known to occur in southeastern Brazil. For each serum, end point titer reacting with each Rickettsia antigen was determined. Serum showing for a Rickettsia species titer at least fourfold higher than that observed for any other Ricketttsia species was considered homologous to the first Rickettsia species or to a very closely related genotype. A total of 164 rural and 153 urban dogs were tested. Overall, 19 (11.6%) and 6 (3.9%) dogs from rural and urban areas, respectively, reacted positively to at least one Rickettsia species. In the rural area, three sera showed titers to R. parkeri at least four-fold higher than any of the other five antigens. These sera were considered to be homologous to R. parkeri or a very closely related genotype. Using the same criteria, two rural sera were considered homologous to R. amblyommii, two other rural sera to R. rhipicephali, and one urban serum to R. parkeri. Because dogs living in the rural area of Monte Negro are commonly infested by the same tick species infesting humans, they indeed serve as sentinels for human rickettsial diseases. Thus, humans living in Monte Negro are likely to be infected by at least three Rickettsia species: R. parkeri, R. amblyommii, and R. rhipicephali. While R. parkeri is a known human pathogen, further studies are required to verify the potential role of R. amblyommii and R. rhipicephali as human pathogens.

Prevalence of Ehrlichia canis (Rickettsiales: Anaplasmataceae) in dogs and Rhipicephalus sanguineus (Acari: Ixodidae) ticks from Brazil.

The current study evaluated the prevalence of Ehrlichia canis Donatien and Lestoquard in domestic dogs, Canis familiaris L., and Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) ticks from different areas of Brazil. In Monte Negro County (state of Rondônia, Brazilian western Amazon), the indirect immunofluorescence assay detected E. canis-reactive antibodies (titer > or = 40) in 58/153 (37.9%) and 40/161 (24.8%) dogs from the urban and rural areas, respectively. These values were significantly different between the two areas. Ticks from a household in the urban area of Monte Negro, and from households in three other localities (162-165 adult ticks per household) in the state of São Paulo (SP) were tested by polymerase chain reaction (PCR) targeting an erlichial dsb gene fragment. The prevalence of infected ticks (given as minimal infection rate) was 2.3, 6.2, and 3.7% for populations 1 (Monte Negro), 2 (Jundiaí, SP), and 3 (São Paulo I, SP), respectively, which were statistically similar. In contrast, no infected tick was detected in population 4 (São Paulo II, SP). DNA sequences were determined for some of the PCR products generated from ticks and dogs from populations 1-3, being all identical to each other and to available sequences of E. canis in GenBank. These results reinforce previous records of E. canis-infecting dogs in Brazil. Natural infection of R. sanguineus ticks by E. canis is reported for the first time in Brazil, where this tick is the commonest species infesting dogs.

A preliminary investigation of Ehrlichia species in ticks, humans, dogs, and capybaras from Brazil.

A molecular epidemiologic investigation in two Brazilian states (Rondônia and São Paulo) was undertaken to determine if Ehrlichia species responsible for human and animal ehrlichioses in North America could be found in Brazilian vectors, potential natural mammalian reservoirs and febrile human patients with a tick bite history. Samples, including 376 ticks comprising 9 Amblyomma species, 29 capybara (Hydrochaeris hydrochaeris) spleens, 5 canine blood, and 75 human blood samples from febrile patients with history of tick bites were tested by a real-time PCR assay targeting a fragment of the Ehrlichia dsb gene. Ehrlichia DNA was not detected in any tick, capybara or human samples. In contrast, 4 out of 5 dogs contained Ehrlichia canis DNA in their blood, which were sequenced, representing the first report of E. canis infecting dogs in the Amazon region of Brazil. Further studies are needed to evaluate the presence of other agents of human and animal ehrlichioses in Brazil.