Diagnóstico sorológico e aspectos epidemiológicos de Theileria equi e Borrelia spp. em equinos de uso militar, no município de Resende, Rio de Janeiro

Abstract

The tick-borne diseases in addition to have a worldwide distribution, related to the dispersion of these vectors, and a complex epidemiologic network, making them difficult to control and prevention, cause major impacts on human and animal health. Brazil, the second largest herd of horses in the world, has the Theileria equi as a major hemoparasites transmitted by ticks to such animals, causing serious barriers to equideocultura in the country, which is considered endemic. Moreover, some aspects of its epidemiology, as the real vector of the disease in the country, are still not well understood. Regarding zoonotic diseases that the animals are involved, an emerging borreliosis, the Baggio - Yoshinari Syndrome, has drawn attention because horses seropositive for Borrelia spp. has been evidenced in our country, suggesting possible involvement of these animals in its epidemiology. Thus, this study aimed to perform serological diagnosis and assess the risk factors associated with seropositivity for Theileria equi and Borrelia spp. in the herd of horses for military use in the municipality of Resende, state of Rio de Janeiro. Samples of 174 horses for military use were tested by indirect ELISA immunoassay for Theileria equi and Borrelia burgdorferi strain G39/40. The dependent variable (seroreactivity) was tested through bivariate analysis for the association as the independent variables (gender, age, racial definition, group management, creation time in AMAN, system creation, origin of the horse, the presence of infestation by Dermacentor nitens, by Amblyomma cajennense, level of tick infestation and presence of tick infestation). The variables that were associated in bivariate analysis (p < 0.25) were included in the logistic regression model for multivariate analysis. It was found that the prevalence Borrelia spp. was 29.89%, and the T. equi prevalence was 74.14 %. Multivariate analysis demonstrated that the presence of tick infestation is associated (p < 0.05) with seropositivity for Borrelia spp. in horses (OR 3,45; CI 1,2 – 9,7), and the creation time in AMAN greater than 15 years associated with seropositivity for T.equi (OR 5,70; CI 1,23 - 22,1). From the results obtained it can be inferred that ticks are related in the transmission of Borrelia spp in the herd studied, with their probable vectors. Further evidence of circulating Borrelia spp. in horses reinforces their role as sentinels, warning of the occurrence of human cases. Regarding Theileria equi, it was found that the area is endemic for the disease with a high prevalence of asymptomatic carriers, evoking care and preventive measures in the introduction of horses, coming from areas unaffected or enzootic instability, in the herd.