Ontario. Equine arteritis virus isolated from a Standardbred foal with pneumonia.

n April of 1988 a five-day-old male Standardbred foal was presented for necropsy to the Veterinary Laboratory Services Branch of the Ontario Ministry of Agriculture and Food. Postmortem examination revealed bronchointerstitial pneumonia and petechial hemorrhages in the kidney and adrenal cortices. On June 15, a virus was isolated from a lung-spleen tissue pool, using both equine dermis cells and a rabbit kidney cell line (RK-13). This isolate passed through a 50 nm filter and was resistant to chloroform. Fluorescent antibody tests for EHV-1, adenovirus, and influenza A were negative. On July 7 the isolate was forwarded to the New York State Diagnostic Laboratory for confirmation of a diagnosis of equine arteritis virus (EAV). Fluorescent antibody assays, using polyclonal antiserum specific for EAV that had been prepared in a colostrum-deprived foal, confirmed a diagnosis of EAV on July 28. This is the first time EAV has been isolated in Ontario.