Infecção e diversidade genética de Babesia caballi e Theileria equi em equídeos do estado de Mato Grosso.

Abstract

Equine piroplasmosis is a tick-borne disease caused by the hemoprotozoa Theileria equi and Babesia caballi. It has economic importance due to the impact on the international movement of horses for trade and for participation in events. The aim of this study was to investigate the distribution of T. equi and B. caballi in equidae from the Mato Grosso state, by molecular methods to identify risk factors associated with positivity and to evaluate the genetic diversity of the agents. We examined 1624 equidae, distributed in 973 farms, and the epidemiological data of animal and property. Polymerase chain reaction (PCR) was identified by amplification of a fragment of the EMA-1 (Erythrocyte merozoite antigen 1) gene of T. equi gene () and a fragment of the RAP-1 (Rhoptry associated protein-1) gene () of B. caballi. For molecular characterization and phylogenetic studies, 13 and 60 sequences of the RAP-1 and EMA-1 genes, respectively, were used to construct a dendogram using maximum parsimony. The molecular prevalence of B. caballi infection in animals was 2.74%, and T. equi was 25.91%. In the analysis of the variables, equidae raised in the Pantanal are less likely to be infected by B. caballi and T. equi in 2.9% and 19.65% respectively. Animals aged 6 months to 2 years and 11 months presented a 1.20 times greater chance of being infected by T. equi, while animals older than 10 years presented 10.08% less chance of being infected by T. equi. The prevalence of positive properties was 4.11% for B. caballi and 28.16% for T. equi. The location of the property in the Pantanal biome decreased the chance of being positive for T. equi in 56.23%, and the properties that used equidae to perform the farm service were less likely to have T. equi infected animals .equi in 83.02%. In the phylogenetic analysis, B. caballi sequences presented intraspecific variability of 1.95%, contrasting with 2.99% in T. equi, but they did not allow us to distinguish the subgroups related to the different biomes. Equine piroplasmosis occurs in the state of Mato Grosso, with higher prevalence of both agents, in animals and in properties in the Amazon biome, followed by the Cerrado and the Pantanal.