Frequency of seropositive equines for Theileria equi in the Southern Rio Grande do Sul State, Brazil

a study on equine theileriosis was carried out in the southern region of the brazilian state of rio grande do sul (rs). blood samples were collected from 113 mares from an equine breeding farm located in the city ofbagé, latitude 31 "30's and a longitude of 54 u10' w. the serological testing was carried out with the use of indirect fluorescence test (ifat) and compared with nested polimerase chain reaction (npcr). among the sera collected from 118 horses, 25 were found positive to theileria equi by the ifat, while by npcr 17 positive for t. equi was observed, corresponding to a frequency of22.1%> and 15.0%, respectively. the racial analysis showed 15.05% (14) thoroughbred and 55% (11) crioulo breed horses to be positive by ifat.