Agentes da theileriose e da anaplasmose granulocítica em equídeos de microrregiões do estado do Rio de Janeiro

Abstract

This study was carried out in the microregions of Itaguaí and Serrana, State of Rio de Janeiro in order to study of granulocytic anaplasmosis and theileriosis equine agents. Blood and serum samples were subjected to indirect fluorescent antibody test (IFAT), real time polymerase chain reaction (RT-PCR) and hematological analysis. The overall prevalence for T. equi was 81.09% (n=579), with higher prevalence (p<0.05) for Itaguaí microregion (85.43%), when compared to Serrana (76.92%). The region, altitude, level of farm and origin of horses were associated (p<0.05) with seropositivity for T. equi. Horses reared in the Itaguaí microregion had 11% more likely (PR=1.11, p=0.003) of having contact with T. equi compared to those reared in the Serrana microregion. Moreover, when are raired at altitudes below 500m showed 10% chance less (PR=1.10; p=0,014) of becoming seropositive. Horses reared in poor level farms (PR=1.13, p=0.018) and born on the farm (PR=1.10, p=0.008) showed more chance of having contact with T. equi. The main ticks found attached in horses were Amblyomma cajennense and Dermacentor (Anocentor) nitens. The frequency of seropositive horses for A. phagocytophilum was 17% (n=17) of the samples tested in the Seropédica county. No association (p>0.05) was observed among the studied factors and seropositivity of horses to A. phagocytophilum. Of 350 samples tested by RT-PCR, 0.86% (n=3) showed specific amplification for msp2 gene. The positive samples showed average CT value of 35.09±1.48 cycles and Tm of 78.56±0.53°C, similar to the positive control, 78.45±0.32°C. The Itaguaí and Serrana microregions are endemic for equine theileriosis and of enzootic stability for T. equi. Only factors related to collection area influenced the seropositivity of horses for T. equi in the microregions studied. The presence of anti-A. phagocytophilum antibodies and molecular evidence of infection by this pathogen in horses of Seropédica municipality in the Rio de Janeiro state, suggests the circulation of A. phagocytophilum in this region.