ABSTRACT
The occurrence of EHV-1 antibodypositive horses was determined on serum samples collected from 1,341 animals of 30 farms from the northwest of São Paulo-Brazil. Antibody against EHV-1 was detect by virus neutralization in 365 (27.2%) horses. All farms, except one in Penápolis city, showed positive animals although abortion was just observed in 6 farms. The high antibody level described in association with asymptomatic infected horses suggested that EHV-1 infection can be more frequent than have been reported in Brazil.
KEY WORDS:
Equine herpesvirus 1; EHV-1; antibody.