Molecular detection of Hepatozoon canis and Babesia canis vogeli in domestic dogs from Cuiabá, Brazil

Tick-borne pathogens Ehrlichia, Hepatozoon, and Babesia co-infection in owned dogs in Central Thailand

Tick-borne pathogens are transmitted by a wide range of tick species and affect both human and animal health. Understanding the diversity of these pathogens and their co-infection rates in domesticated animals in urban areas is crucial for effective disease management and prevention. In this study, a total of 565 owned dogs in the central region of Thailand were investigated for the infection rate of three genera of Ehrlichia, Hepatozoon, and Babesia infection using multiplex PCR. The results revealed an overall infection rate of 19.1%, with Ehrlichia having the highest infection rate (12.2%), followed by Babesia (2.5%) and Hepatozoon (1.4%). The rate of co-infection was 3%, with mixed infections involving two or three genera. Male dogs exhibited a slightly higher infection rate compared to females, although not statistically significant. Young adult dogs (1-3 years) showed the highest infection rate of both single infections and co-infections. Monthly infection rate indicated variations throughout the year, with co-infection rate significantly associated with overall infection rate. Clinical manifestations in three genera of infected dogs included thrombocytopenia and eosinopenia. The results of this study are useful to design strategies for the management and prevention of tick-borne diseases in the study area.

Canine piroplasmids: Molecular detection and laboratory characterization in dogs from Brasilia, Brazil, with the first molecular evidence of dog exposure to a novel opossum-associated Babesia sp

Canine piroplasmid infections can be caused by Babesia spp., Theileria spp. and Rangelia vitalii. In Brazil, canine babesiosis caused by Babesia vogeli is endemic and reported throughout the country. On the other hand, Rangeliosis caused by R. vitalii has only been described so far in the South and Southeast regions. Despite that, studies analyzing the laboratory and molecular characterization of these hemoprotozoa are still scarce. To investigate the occurrence, the laboratory features, the molecular characterization, and the diversity of piroplasmids from Midwestern Brazil, a survey was performed using blood samples obtained from 276 domestic dogs from Brasília, Federal District, Midwestern Brazil. A broad-range quantitative PCR (qPCR) targeting the mitochondrial large subunit ribosomal DNA (LSU4) was used to detect piroplasmid DNA. The overall molecular occurrence of piroplasmids was 11.2% (31/276), with 9.7% (27/276) of the sequences identified as Babesia vogeli (98-100% identity to B. vogeli isolate from the USA). Based on a partial 18S rRNA sequence pairwise alignment (-250 bp), 1.4% (4/276) of the sequences showed only 76.8% identity with B. vogeli but 100% identity with opossum-associated Babesia sp. (MW290046-53). These findings suggest the exposure of dogs from Brazil to a recently described Babesia sp. isolated from white-eared opossum. None of the analyzed dogs was positive for Theileria spp. or R. vitalii. Subsequently, all positive sequences were submitted to three additional PCR assays based on the 18S rRNA, cox-1, and cytb genes, aiming at performing a haplotype network analysis. Haplotype network using cox-1 sequences showed the presence of six different haplotypes of B. vogeli; one of them was shared with isolates from Brazil, the USA, and India. When including animals co-infected with other vector-borne diseases, piroplasmid-positive dogs had 2.3 times higher chance of having thrombocytopenia than the negative ones. The molecular results demonstrated that the compared Babesia vogeli sequences showed a low variability as well as evidence of exposure to a putative novel opossum-associated Babesia sp. in dogs from Midwestern Brazil.

Occurrence of tick-borne pathogens in dogs in a coastal region of the state of Ceará, northeastern Brazil

The aim of this study was to determine the occurrence of tick-borne pathogens (Ehrlichia canis, Babesia vogeli, Hepatozoon spp. and Rickettsia spp.) in dogs in Vila de Jericoacoara, coastal region of Ceará, Brazil. Blood samples were collected from 153 animals and analyzed using molecular and serological methods. Sixty animals were found to be infected or exposed to at least one of the pathogens studied. Babesia vogeli was the most prevalent pathogen (15%), followed by E. canis (13.7%) and Hepatozoon spp. (11.8%), which was identified as Hepatozoon canis through sequencing. Twenty dogs (13%) were seroreactive to Rickettsia spp. Rhipicephalus sanguineus sensu lato was observed on 11.8% of the animals. There were associations between age (< 3 years old) and positivity for B. vogeli, and between habitation (stray dogs) and positivity for H. canis. There were also associations between anemia and infection with H. canis, and between leukopenia and exposure to Rickettsia spp. No association was detected between clinical alterations and infection with or exposure to the pathogens studied. The results confirmed that pathogens of veterinary importance are circulating in northeastern Brazil and showed that dogs are exposed to Rickettsia species with zoonotic potential, thus indicating a need for vector control measures.

Microscopic Detection, Hematological Evaluation and Molecular Characterization of Piroplasms from Naturally Infected Dogs in Rio de Janeiro, Brazil

PURPOSE

This study aimed to analyze the frequency of piroplasmids in the blood of dogs in Rio de Janeiro, compare the performance of microscopic techniques, assess the risk factors associated with infections and also molecularly and morphologically characterize the piroplasmids identified.

METHODS

In all, 407 blood samples were collected from dogs between 2018 and 2019. These were subjected to microscopic parasitological techniques for thin and thick smears, stained with Giemsa and using a rapid staining kit. The slides were read under an optical microscope and the protozoa were characterized morphometrically. In addition, the blood samples were subjected to molecular characterization for diagnosing piroplasmid species using primers that amplified the gene 18S rRNA.

RESULTS

Piroplasmids were detected in 38 (9.3%) samples. Of these, 33 samples presented nucleotide sequences compatible with Babesia vogeli. Most of the positive samples were young, male, defined breeds dogs that had been attended in clinics in São Gonçalo city. Thrombocytopenia and leukopenia were the hematological alterations more observed in positive samples, but positive samples without alterations were also detected. The sex was the only variable that showed statistical differences. Males dogs being more often infected than females (p < 0.05). The microscope slides mostly showed piriform and oval merozoites measuring greater than 2.5 µm in length, which were compatible with B. vogeli. However, smaller forms were also identified, thus demonstrating the polymorphic nature of this parasite.

CONCLUSION

Babesia vogeli was detected in blood samples from dogs in the metropolitan cities of Rio de Janeiro by molecular techniques in different parasite morphotypes.

Epidemiology of canine visceral leishmaniasis in a vulnerable region in Brazil

Visceral leishmaniasis (VL) is a neglected and endemic zoonosis that occurs throughout Brazil; nevertheless, few studies have focused on the early detection of the disease. The municipality of Ourinhos is a non-receptive, silent and vulnerable area for VL, where the seroprevalence of this disease has so far not been investigated. The present study aimed to determine the seroprevalence of canine VL in Ourinhos-SP, and to identify the presence of risk factors. Blood samples were obtained from 604 dogs during a rabies vaccination campaign together with application of a socioeconomic questionnaire, environmental and animal characteristics and tutor's knowledge about the disease. The samples were subjected to indirect ELISA and new samples were collected from reactive and suspect animals, including whole blood and lymph node aspiration evaluated by parasitological method, complete blood count and PCR. No animal was diagnosed as positive based on the combination of direct and indirect tests and the tutors' answers indicated little knowledge about leishmaniasis, being often confused with other diseases transmitted by arthropods; hence, according to the proposed methods, the presence of canine leishmaniasis in the city of Ourinhos was not confirmed and health education campaigns about the disease should be carried out.

Molecular evaluation of piroplasms and hematological changes in canine blood stored in a clinical laboratory in Niterói, Rio de Janeiro

Piroplasm species were analyzed by molecular tools in total 31 blood samples from positive dogs, previously checked by stained slides, stored until DNA extraction between 2016 to 2018 in the laboratory Clinical Analyzes in Niterói, Rio de Janeiro. The piroplasms were identified by PCR, targeting the 18S rRNA gene and sequencing. From the total number of samples only 24 (77.4%) were positive and show adequate nucleotide sequences for interpretation with identity between 93%-100% with Babesia vogeli in compared to the sequences isolated of infected dogs from other states in Brazil deposited on GenBank. Most of dogs infected with B. vogeli had anemia (62.5%) and thrombocytopenia (95.8%). The findings of this study are compatible with previous reports in the literature and highlight B. vogeli as the most incriminated species in canine piroplasmosis in Brazil, and thrombocytopenia the hematological alteration most frequently identified in this infection. It is important to note that this is the first study involving the molecular characterization of piroplasms in the metropolitan region of Rio de Janeiro, based on PCR followed by sequencing.

Canine babesiosis: A literature review of prevalence, distribution, and diagnosis in Latin America and the Caribbean

Canine babesiosis is a tick-borne disease with worldwide distribution and global significance. Traditionally, canine babesiosis was caused by B. canis (large Babesia) and B. gibsoni (small Babesia) based on cytological examination of stained blood smears. Currently, molecular techniques have demonstrated that several Babesia species infect dogs: B. canis, B. vogeli, and B. rossi (large forms) and B. gibsoni, B. conradae, and B. vulpes (small forms). In this study, we compiled and reviewed currently available data on Babesia infections in dogs in Latin America and the Caribbean, as well as on distribution of Babesia species with respect to prevalence, geographic location, and methods of detection. Forty-three studies on canine babesiosis published from 2005 to 2019 were included. The publications retrieved reported three species of Babesia (B. vogeli, B. gibsoni, and B. caballi) based on molecular confirmation of the species. Babesia vogeli was reported in Mexico, Costa Rica, Granada, Haiti, Nicaragua, Saint Kitts and Nevis, Trinidad and Tobago, Argentina, Brazil, Chile, Colombia, Paraguay, Peru, and Venezuela. In contrast, B. gibsoni was recorded in Costa Rica, Nicaragua, Saint Kitts and Nevis, and Brazil. Babesia caballi was found in a dog from Brazil. Babesia prevalence in dogs varied considerably based on parasite species and geographic location, with values close zero to 26.2%. Besides molecular techniques such as PCR, studies included examination of blood smears by microscopy and/or serologic tests. Few countries in the region, e.g., Brazil and Costa Rica, possess profound data availability, whereas the majority of them have scarce information or no data. A deeper understanding of the ecology and epidemiology of Babesia spp. in dogs is needed for the region.

Employment of the 18s rRNA screening PCR technique in the detection of Equine Piroplasmosis, in horses of sports and military operations, of the Brazilian Army

ABSTRACT The present work had the objective of detecting the occurrence of Equine Piroplasmosis in horses housed in the 3rd Guards Cavalry Regiment (GCR) - Brazilian Army (BA) ˗ Porto Alegre, RS-Brazil, as well as to demonstrate the proactivity of PCR (Polymerase Chain Reaction) technique, aiming at the judicious use of the resources involved in the training and employment of Equines in the Brazilian Army. Fifty horses of the 3rd GCR - Porto Alegre ˗ RS, which are employed for Sport, Military Ceremonial, Law and Order Guarantee Operations (LOGO), were evaluated by means of the 18s r RNA screening with PCR technique, thirty eight horses with Babesia Caballi and Theileria Equi were detected, which corresponds to an incidence of 76% of the horses effective analyzed at the time. In this way, it can be verified that the Military activity have its "performance and effectiveness" factors threatened in case the health of the principal of his means employed, that is the horse, is compromised. The PCR technique then offers a reliable and feasible tool for the detection of Equine Piroplasmosis in BA horses.

Molecular detection of vector borne pathogens in anemic and thrombocytopenic dogs in southern Brazil

Abstract Arthropod-borne pathogens are medically important because of their ability to cause diseases in their hosts. The purpose of this study was to detect the occurrence of Ehrlichia spp., piroplasmids and Hepatozoon spp. in dogs with anemia and thrombocytopenia in southern Brazil. EDTA-whole blood was collected from 75 domestic dogs presenting anemia or/and thrombocytopenia from Guarapuava, state of Paraná, Brazil. DNA samples were subjected to conventional PCR assays for Ehrlichia spp. (dsb), piroplasmids (18S rRNA) and Hepatozoon spp. (18S rRNA), followed by sequencing and phylogenetic analyses. Among the 75 dogs, one (1.33%) was positive for Hepatozoon sp. and six (8%) were positive for piroplasmids in 18S rRNA cPCR assays. None of the dogs showed positive results in Ehrlichia spp.-cPCR targeting dsb gene. The phylogenetic analyses revealed that three piroplasm sequences were clustered with Rangellia vitalii, while one sequence was grouped with B. vogeli. The only sequence obtained from Hepatozoon spp.-PCR protocol was pooled with H. canis. Therefore, there is urgent need for differential molecular diagnosis of the two piroplasm species cited as etiological agents in clinical cases of canine hemoparasitic diseases, given the higher pathogenic potential of R. vitalii than of B. vogeli.

Tick-borne infections in dogs and horses in the state of Espírito Santo, Southeast Brazil

This work aims to identify and quantify the percentage of Rickettsia spp., Ehrlichia spp., Babesia spp. and Hepatozoon spp. positive pet dogs, and to identify ticks collected on these animals in the state of Espírito Santo, in the Southeast region of Brazil. The study included 378 dogs, 226 females and 152 males, of various breeds and ages (mean age of 4.1 years). All animals were examined for ticks, and whole blood was collected and processed by conventional PCR protocols for Babesia spp., Anaplasmataceae, Hepatozoon spp. and by real-time PCR for Ehrlichia canis. Of the 378 dogs examined, 157 (41.53%) had ticks at the time of the study, which were identified as R. sanguineus s.l. in 154 animals (98.10%), Amblyomma ovale in one animal (0.63%), and Amblyomma sculptum in 2 animals (1.27%). In the PCR for Babesia spp., 5 animals (1.32%) were positive, producing DNA sequences 100% identical to Babesia vogeli. For Anaplasmataceae, 34 animals (9%) were positive, 10 of which generated DNA sequences 100% similar to Ehrlichia canis. The other 24 samples generated fragments 100% identical to Anaplasma platys. In the PCR for Hepatozoon spp, 39 animals (10.31%) were positive, producing sequences 100% identical to Hepatozoon canis. Finally, in the real-time PCR specific for E. canis, 28 animals (7.40%) were positive. Coinfection with 2 or 3 agents was observed in 20 animals (5.29%). Of the 378 dogs sampled, 312 were analyzed by indirect immunofluorescence assay (IFA) for E. canis and five species of Rickettsia (R. rickettsii, R. parkeri, R. amblyommatis, R. rhipicephali and R. bellii). Among them, 71 dogs (22.75%) had a positive reaction for E. canis and 16 dogs (5.13%) had antibody titers higher than 64 to at least one Rickettsia species, 5 of them (1.60%) to R. rickettsii. Samples of blood were collected from 10 equines in the regions where dogs were found with positive serology for any one of the Rickettsia sp. tested. In the municipality of Vila Velha, two equines were positive for R. bellii with inverse titers of 64 and 128. These results indicate that tick-transmitted agents, such as E. canis, A. platys, B. vogeli, H. canis, and several spotted fever group Rickettsia are circulating in the canine population of the Brazilian state of Espirito Santo.

Survey of Ehrlichia canis, Babesia spp. and Hepatozoon spp. in dogs from a semiarid region of Brazil

This study assessed the occurrence of Ehrlichia spp., Babesia spp. and Hepatozoon spp. infections in 100 tick-harboring dogs from a semiarid region of the State of Paraíba, Northeastern Brazil. Blood samples and ticks were collected from the animals, and a questionnaire was submitted to dog owners to obtain general data. Blood samples were used to perform hemogram, direct blood smear and immunological and molecular hemoparasite detection. The 1,151 ticks collected were identified as Rhipicephalus sanguineus; direct smears revealed E. canis-like morulae in the monocytes of 4% (4/100) of the non-vaccinated female dogs, and 34% and 25% of the dogs tested positive for Ehrlichia canis by indirect immunofluorescence assay (IFA) and polymerase chain reaction (PCR), respectively. Blood smear examination revealed Babesia-suggestive merozoites in the erythrocytes of 2% (2/100) of the animals. Babesia vogeli was detected by PCR in ten animals (10%) and was correlated with young age (p = 0.007) and thrombocytopenia (p = 0.01). None of the animals showed Hepatozoon spp. positivity. These results indicate that E. canis is the main tick-borne canine pathogen in the study area and provide the first report of B. vogeli infection in dogs from Paraiba State.

Seroprevalence of Tick-Borne Pathogens and Tick Infestation in Dogs from Tapirapé and Karajá Indigenous Communities, Brazil

With the aim of studying some tick-borne diseases, a total of 327 dogs (114 from Tapirapé and 213 from Karajá indigenous ethnicity, Mato Grosso, MT, Brazil) were sampled. Serum samples were submitted to the indirect fluorescence antibody test (IFAT) to detect antibodies against Babesia vogeli, Ehrlichia canis, and Rickettsia spp. Possible associations of risk factors and the occurrence of seroreativity to tick-borne agents and tick infestations were analyzed through chi-squared tests. Among 327 dogs, 46 (13.15%) were seropositive for B. vogeli and 47 (14.37%) for E. canis. The B. vogeli seroprevalence was higher for Karajá and for adult dogs (p>0.05). No association was found for E. canis seroprevalence. From 103 serum samples tested with rickettsial antigens, 90 (87%) dogs were seropositive to Rickettsia spp., with highest reactivity to Rickettsia amblyommii. Canine seropositivity to Rickettsia spp. was associated (p<0.05) with ethnicity (higher seroprevalence in Tapirapé dogs), age (higher in adults), and hunting (higher among hunting dogs). From the 327 dogs, 39 (11.9%) were infested by ticks (Amblyomma cajennense sensu stricto, Amblyomma ovale, Amblyomma oblongoguttatum, Amblyomma tigrinum, and Rhipicephalus sanguineus). Infestations by Amblyomma spp. ticks were higher in dogs from Tapirapé community and in hunting dogs (p<0.05). Regarding R. sanguineus, infestations were higher (p<0.05) among young dogs.

Rangelia vitalii in a free-ranging maned wolf (Chrysocyon brachyurus) and co-infections

An adult free-ranged female maned wolf was rescued from a periurban area subject to anthropogenic disturbances in the Minas Gerais, Brazil. The animal presented poor body condition and anemia. The clinical condition rapidly deteriorated culminating in dead and a necropsy was performed. The main gross lesions were marked anemia and blood content in the intestines accompanied by many types of parasites. The protozoa Rangelia vitalii was identified by histopathological analysis predominantly within the cytoplasm of endothelial cells of capillaries of the small intestine. The lymph nodes, spleen, bone marrow, dermis, lungs and kidney had similar protozoal forms but with mild or moderate intensity. Rangelia vitalii was confirmed by molecular assays. Hepatozoon sp., Leishmania sp., and Entamoeba spp., apparently not related to the clinical signs were also detected. The myriad parasites found in the intestines included nematodes (Ancylostoma caninum, A. braziliensis,, Molineus sp., Pterygodermatites sp., and Trichuris sp.), cestodes (Spirometra sp.) and (acanthocephalans. To our knowledge, R. vitalii was identified in C. brachyurus for the first time. These findings emphasize the fragility of Brazilian ecosystems, especially in disturbed areas, reinforcing the necessity of efforts to preserve these areas and wild carnivores, some of which are threatened with extinction, such as the maned wolf.

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Rangelia vitalii was found in Chrysocyon brachyurus, especially in small intestine.

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Co-infections with other parasites were found, including some with zoonotic potential.

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Anemia was likely linked to R. vitalii, Ancylostoma spp and perhaps Spirometra.

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Health status of the near threatened maned wolf reflects anthropogenic disturbed of habitat.

Detecção de Theileria equi e Babesia caballi e anticorpos anti-Ehrlichia spp. em equídeos do Pantanal Mato-Grossense, Brasil

O presente estudo avaliou equídeos de 19 fazendas da região do Pantanal Mato-Grossense, sendo 121 equídeos testados pela reação em cadeia pela polimerase (PCR), para detectar fragmentos dos genes dos seguintes gêneros: Babesia, Theileria, Anaplasma, Ehrlichia, e Neorickettsia, e pela reação de imunofluorescência indireta (RIFI), para detectar anticorpos anti-Ehrlichia spp. Das amostras testadas na PCR, 17 (14,0%) animais de nove (47,3%) fazendas foram positivos. Das amostras positivas, 16 foram 100% idênticas a sequencias de Theileria equi e uma foi 99% similar à sequência de Babesia caballi, todas disponíveis no GenBank. Pela RIFI, 48 (39,6%) equídeos foram soropositivos para antígenos de E. canis, sendo 40 (83,3%) amostras com títulos de 40 e oito (16,6%) com títulos de 320. Todas as fazendas avaliadas (100%) apresentaram equídeos soropositivos. Os resultados do presente estudo demonstram que T. equi e B. caballi infectam equinos na região, e a presença de anticorpos anti-Ehrlichia spp. indica a circulação de espécies antigenicamente relacionadas aos gêneros Ehrlichia e Anaplasma, apesar de a negatividade nos exames de PCR indicar provável processo crônico desses agentes.

Survey of canine tick-borne diseases in Lábrea, Brazilian Amazon: ‘accidental’ findings of Dirofilaria immitis infection

Blood samples were collected from 99 domestic dogs from the urban and rural areas of the Lábrea municipality, state of Amazonas, Brazil. Canine serum samples were tested by immunofluorescence assay against Rickettsia spp., which revealed that only 3.0% (1/33) and 7.6% (5/66) of the dogs from urban and rural areas, respectively, reacted positively to at least one Rickettsia species. DNA was extracted from canine blood and tested by a battery of PCR assays targeting protozoa of the genera Babesia and Hepatozoon, and bacteria of the genera Rickettsia and Ehrlichia and family Anaplasmataceae. All samples were negative in the PCR assays targeting the genera Babesia, Hepatozoon, Ehrlichia and Rickettsia. For Anaplasmataceae, 3% (1/33) and 39.4% (26/66) of the urban and rural dogs, respectively, yielded amplicons that generated DNA sequences 100% identical to the corresponding sequence of Wolbachia endosymbiont of Dirofilaria immitis. Because of these results, all canine DNA samples were further tested in a PCR assay targeting filarial nematodes, which was positive for 18.2% (6/33) and 57.6% (38/66) urban and rural dogs, respectively. Filarial-PCR products generated DNA sequences 100% identical to D. immitis. While tick-borne infections were rare in Lábrea, D. immitis infection rates were among the highest reported in South America.

Optimization of a molecular method for the diagnosis of canine babesiosis

Babesiosis is a hemolytic disease caused by protozoans of the genus Babesia (Apicomplexa). This disease occurs worldwide and is transmitted by ticks to a variety of mammals, including humans. The objective of the present study was to optimize a molecular approach for the detection of a fragment of 18S rDNA of Babesia canis, Babesia vogeli, Babesia rossi or Babesia gibsoni based on a single semi-nested Polymerase Chain Reaction (PCR), and compare the efficiency of this approach with that of a simple PCR protocol. To this end, 100 blood samples collected from dogs with suspected hemoparasite infections were analyzed. A comparison of the results of simple PCR and semi-nested PCR indicated a highly significant difference (p value = 0.0000). While only five (5%) of the samples tested positive using the simple protocol, 22 (22%) were positive using the snPCR technique. The results of this study reinforce the findings of previous studies, which have demonstrated the greater sensitivity of tests based on nested or semi-nested PCR. Therefore, to avoid false-negative results due to low levels of parasitemia, we suggest the preferential use of this protocol in epidemiological studies of canine babesiosis, particularly those that require reliable estimates of the prevalence of infection.

Molecular and serological detection of tick-borne pathogens in dogs from an area endemic for Leishmania infantumin Mato Grosso do Sul, Brazil

Tick-borne pathogens affect a wide range of vertebrate hosts. To identify tick-borne pathogens among dogs from Campo Grande, MS, Brazil testing seropositive for Leishmania infantum (syn. L. chagasi), a serological and molecular study was conducted to detectEhrlichia canis, Anaplasma platys and Babesia vogeli in 60 serum and spleen samples. A confirmatory diagnosis ofL. infantum based on serological and molecular assays was also performed, as was sequence alignment and phylogenetic analysis to assess the identity of the parasite species infecting these animals. IgG antibodies toEhrlichia spp., B. vogeli and L. infantum were found, respectively, in 39 (65%), 49 (81.6%) and 60 (100%) of the sampled dogs. Twenty-seven (45%), fifty-four (90%), fifty-three (88.3%), two (3.3%) and one (1.6%) dog were positive, respectively, forE. canis, Leishmania spp., Leishmania donovani complex, Babesia sp. and Anaplasma sp. in PCR assays. After sequencing, the amplicons showed 99% of identity with E. canis, B. vogeli, A. platys andLeishmania chagasi isolates. The findings of this study indicate that L. infantum-seropositive dogs from Campo Grande are exposed to multiple tick-borne pathogens, which should therefore be included in the differential diagnosis of dogs with clinical suspicion of leishmaniasis.

Serosurvey for tick-borne diseases in dogs from the Eastern Amazon, Brazil

Canine ehrlichiosis and babesiosis are the most prevalent tick-borne diseases in Brazilian dogs. Few studies have focused attention in surveying tick-borne diseases in the Brazilian Amazon region. A total of 129 blood samples were collected from dogs living in the Brazilian eastern Amazon. Seventy-two samples from dogs from rural areas of 19 municipalities and 57 samples from urban stray dogs from Santarém municipality were collected. Serum samples were submitted to Indirect Immunofluorescence Assay (IFA) with antigens ofBabesia canis vogeli, Ehrlichia canis, and six Rickettsia species. The frequency of dogs containing anti-B. canis vogeli, anti-E. canis, and anti-Rickettsia spp. antibodies was 42.6%, 16.2%, and 31.7%, respectively. Anti-B. canis vogeli antibodies were detected in 59.6% of the urban dogs, and in 29.1% of the rural dogs (P < 0.05). For E. canis, seroprevalence was similar among urban (15.7%) and rural (16.6%) dogs. ForRickettsia spp., rural dogs presented significantly higher (P < 0.05) prevalence (40.3%) than urban animals (21.1%). This first study on tick-borne pathogens in dogs from the Brazilian eastern Amazon indicates that dogs are exposed to several agents, such asBabesia organisms, mostly in the urban area; Spotted Fever group Rickettsia organisms, mostly in the rural area; andEhrlichia organisms, in dogs from both areas studied.