The Guarapiranga Dam region, in the metropolitan area of São Paulo, has been an endemic area for Brazilian spotted fever (BSF), a tick-borne disease caused by the bacterium Rickettsia rickettsii. In this particular area, R. rickettsii is known to be transmitted to humans by Amblyomma aureolatum, a typical dog tick that is not associated with horses. In other BSF-endemic areas, R. rickettsii transmission is associated with Amblyomma sculptum, a tick species that typically infest capybaras and horses. The Guarapiranga Dam bears abundant populations of capybaras and horses; however, since nothing is known about a possible cycle of transmission of R. rickettsii by A. sculptum in this area, this study evaluated such transmission by performing a serosurvey of horses living in the Guarapiranga Dam region. A total of 206 equids living in the margins of the Guarapiranga Dam were serologically tested for antibodies reactive to five Rickettsia species, four of the spotted fever group (R. rickettsii, R. parkeri, R. amblyommatis, R. rhipicephali) and one basal group species, R. bellii. Overall, 171 (83%) equids reacted positively to at least one Rickettsia species. A total of 160 (78%), 123 (60%), 80 (39%), 72 (35%), and 71 (34%), equid sera reacted to R. bellii, R. rickettsii, R. parkeri, R. rhipicephali, and R. amblyommatis, respectively, with endpoint titers ranging from 64 to 1024 for R. bellii, and 64 to 512 for the remaining four Rickettsia species. Endpoint titers to R. bellii (median: 256) was significantly higher (P<0.05) than the endpoint titers to the other four Rickettsia species, for which the median values varied from 64 to 128. A total of 65 (32%) equid sera showed endpoint titers to R. bellii at least 4-fold higher than those to any of the other four antigens, indicating that they have been exposed to R. bellii or a very closely related species. Our results provide serological evidence that the sampled equids were not frequently exposed to R. rickettsii-infected ticks. Since horses are a highly suitable sentinel for R. rickettsii transmission by A. sculptum, we conclude that this tick species has no epidemiological role in the transmission of R. rickettsii in the BSF-endemic area of the Guarapiranga Dam in the metropolitan area of São Paulo Municipality.

Brazilian spotted fever is a serious and lethal illness for humans and is caused by the Rickettsia rickettsii bacteria. In the state of São Paulo/SP (Brazil), the etiological agent of this disease is transmitted by the Amblyomma sculptum tick. It was already shown that horses infected with this bacteria produce a strong immune response and could be important sentinels for the detection of the disease in a proper region. The present investigation performed a serological survey in horses from five farms of Vale do Paraíba, São Paulo state, Brazil, searching for antibodies against, Rickettsia rickettsii, Rickettsia parkeri, Rickettsia amblyommatis, Rickettsia rhipicephali, and Rickettsia bellii. In each farm, ticks were also collected that were taxonomically identified and examined by real-time PCR for Rickettsia spp DNA. Blood samples were collected from 206 horses, and 334 ticks were picked up from these animals from January to December 2017. Eighty ticks wereA. sculptum and 254 Dermacentor nitens. Of the blood samples, 7.3% seroconverted to Rickettsia spp. Of these, 0.97% had a positive serological response to R. bellii. None of the 80 A. sculptum ticks were positive through real-time PCR for Rickettsia spp. Although there was no detection of ticks infected by Rickettsia spp in five farms of Paraíba Valley, the horses presented serological positive reactions against this agent. Thus, further large studies should be conducted in the area targeting hosts and vectors to generate data for control measures of the transmission of Brazilian spotted fever.

A leptospirose é uma enfermidade infectocontagiosa que pode acometer os animais e o homem. Nos países tropicais e em desenvolvimento ocorrem 70% dos casos humanos, com mortalidade variando entre 10 a 70%. Os cães podem se tornar portadores assintomáticos por um longo período, podendo transmitir a Leptospira para humanos. Devido ao intenso convívio com o ser humano, os cães podem servir como sentinelas da contaminação ambiental. Esse trabalho investigou a frequência de ocorrência da leptospirose canina em populações assintomáticas da região sudoeste do estado de São Paulo. Para isso foram examinadas pela técnica de soroaglutinação microscópica (MAT), amostras de sangue provenientes de 572 cães assintomáticos dos municípios de Apiaí, Cananeia, Itapeva e Itu por amostragem de conveniência, oriundos de campanhas de castração. Em Apiaí, foram encontrados 40,5% dos animais reagentes para Leptospira spp.; em Itapeva, 42,6%; em Cananeia, 7,7% e em Itu, 5,1%. Os dados encontrados demonstram que, pelo menos, um animal dos municípios de Itapeva, Apiaí e Cananeia apresentaram título igual ou maior que 800, indicando a circulação da bactéria nessas localidades e que a equipe envolvida nas campanhas de castração precisam ser alertadas sobre o correto uso de equipamento de proteção individual, principalmente no esvaziamento mecânico da bexiga antes do procedimento cirúrgico. O estudo também sugere que as campanhas de castração podem ser estratégicas no monitoramento de doenças zoonóticas e poderiam auxiliar no estabelecimento de ações preventivas para a saúde humana e animal.

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OBJECTIVE: To evaluate hematological changes in dogs diagnosed with Ehrlichia canis. METHODS: 54 dogs treated at the Veterinary Hospital of the Santo Amaro University were analyzed. During the consultation, the animals' real temperature was measured; and venous blood samples were collected for hemogram; and performed serological and molecular tests, through Immunofluorescence and PCR in real time, respectively. RESULTS: Among the 54 animals suspected of having E. canis, 32 (59.3%) were diagnosed as positive. Of these, 23 (42.6%) were positive only in the serological test, while 9 (16.7%) had positive results in the serological and molecular tests. Thrombocytopenia was the most important alteration found in this study and was the only parameter found in the blood count that showed a statistical difference. CONCLUSION: It was concluded that thrombocytopenia was the main finding in infected animals and that the combination of molecular and serological diagnoses may increase the chances of detection of infection or exposure to the agent.