Seroprevalence of antibodies against equine arteritis virus in horses residing in the United States and imported horses

Objective-To compare seroprevalence of antibodies against equine arteritis virus (EAV) in horses residing in the United States with that of imported h orses. Design-Serologic survey. Sample Population-Serum samples from 364 horses on 44 equine operations in California and 226 horses imported from various countries. Procedure-Serum samples were collected from each imported horse and from up to 20 horses on each operation. For resident horses, the number of sampled horses on each operation was determined on the basis of the number of hors es on the operation. Samples were tested for antibodies against EAV by use of a serum neutralization test. Results-1.9% of resident horses and 18.6% of imported horses were seroposit ive to EAV, including 16.1% of imported stallions. Conclusions and Clinical Relevance-Results indicate that the EAV seropreval ence of horses residing in California is considerably lower than that of im ported horses, including imported stallions.