In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. | Photo: Kevin Thompson/The Horse

On Jan. 18, the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) received notice of two cases of equine herpesvirus-1 (EHV-1) abortion at a farm in Haldimand County, Ontario, Canada, the agency said in a statement.

“The two mares aborted during their ninth and 10th months of pregnancy,” OMAFRA said. “One week prior to the abortions, two horses on the same farm suddenly developed neurological signs consistent with the neurological form of EHV-1 infection, also known as equine herpes myeloencephalopathy (EHM). These horses were euthanized and no further diagnostic testing was performed. The farm owner has voluntarily placed the premises under quarantine to reduce the risk of disease transmission.”

The agency said current EHV-1 vaccines that protect against abortion should be administered during the fifth, seventh, and ninth months of pregnancy and according to the manufacturer’s guidelines