Seroprevalence and risk factors associated with seropositivity for equine encephalomyelitis virus in horses in Rio Grande do Norte, Brazil

ABSTRACT The present objective was to investigate the presence of anti-equine viral encephalomyelitis (EVE) antibodies and the possible risk factors for its dissemination in horses raised in the East and West Potiguar mesoregions of the state of Rio Grande do Norte, Brazil. Serological diagnosis for neutralizing antibodies against Eastern (EEEV), Western (WEEV) and Venezuelan (VEEV). Equine viral encephalomyelitis was performed using a seroneutralization technique on 811 blood samples from horses from ninety properties and sixteen municipalities between July 2018 and February 2019. Factors associated with EVE were evaluated using an investigative epidemiological questionnaire, and the data were statistically analyzed using the Epi Info 3.5.2 software with a confidence level of 95%. The seroprevalence of anti-EVE antibodies was 14.2% (115), with 10.36% (84) for EEEV, 6.9% (56) for WEEV, and null for EVE. When analyzing risk factors, it can be concluded that horses raised in properties that do not clean installations and/or rent out their pasture are more likely to have anti-EVE antibodies. These results show evidence that horses raised in the East and West Potiguar mesoregions were exposed to EEEV and WEEV, thus reinforcing the importance of vaccination and serological survey of nonvaccinated horses as a means of monitoring the disease.