MEDICINA VETERINÁRIA SEROLOGICAL EVIDENCE OF EXPOSURE TO Anaplasma phagocytophilum IN HORSES FROM THE RIO DE JANEIRO STATE MOUNTED POLICE BRED IN THE URBAN ZONE

Anaplasma phagocytophilum is an emergent hemoparasite in regions where ticks are regularly found. In order to investigate the rate of anti-A. phagocytophilum antibody in horses of the Mounted Police of Rio de Janeiro state and therefore the presence of this agent, 41 horses from the Cavalry Squadron (CS) and 50 from the Regiment of Mounted Police (RMP) were selected. For the serologic diagnosis the Indirect Fluorescent Antibody test was performed. In the present work, among 91 equine sera samples anti-A. phagocytophilum antibodies, with titer ≥ 1:80, were detected in 11 animals (12%), being five (5%) from males and six (7%) females, with no statistical difference. The adult animals with ages varying between five and 14 years presented the highest rate of positive reaction, although antibodies were detected in animals of all ages. We did not observe statistic differences in relation to the presence of anti-A. phagocytophilum antibodies among the animals bred in the CS and RMP. The presence of anti-A.phagocytophilim antibodies in horses of the Mounted Police with no clinical signs is indicative that the parasite is present in the enzootic form among the horses of the urban area. The circulation of the parasite among the animals is not dependent of the presence of tick infestations