Serological Survey of Equine Coronavirus Infection in Horses in Hokkaido, Japan

Abstract

For the serological survey of equine coronavirus (ECoV) infection, 560 equine serum samples collected from the Tokachi area, Hokkaido, Japan from 1989 to 2009 were examined using virus neutralization tests. The results revealed a high prevalence rate (84.4%‐100%) of antibodies against ECoV in each year except 2004, indicating that ECoV has been prevalent among horses in the Tokachi area at least from 1989. In addition, a total of 18 serum samples, collected three times from six horses in the stables of the racetrack where the ECoV outbreak had occurred in the past, were examined against two ECoV strains (isolated during the outbreaks at this racetrack) and bovine coronavirus (BCoV) using a neutralization test. The prevalence rate and geometric mean titers of antibodies against ECoV were higher than those of antibodies against BCoV. Furthermore, antigenic differences were also observed between ECoV strains in the neutralization tests.