The seroprevalence of equine trypanosomosis in the pantanal

Since little information is available on the epizootiological status of Try panosoma evansi in South America and particularly, Brazil, Mle evaluated eq uine serum samples collected in 1993, 1994, 1995 and 1997 for the presence of antibodies against this trypanosome species. Our study shows corroborati ve evidence about the correlation among high T, evansi seroprevalence and t he rainy season in the Pantanal, Brazil. The higher seroprevalence was 79.2 % in horses from a ranch located iii the Nhecolandia subregion ill 1994 and the lower 5.8% in animals from the same ranch in 1997. No seroprevalence w as found in 1993. The possible re-introduction of T. evansi in the region a s well as the relationship among our results with the outbreaks reported in 1994, are briefly discussed.