In many horses, the first sign of EHV-1 infection is fever, which can go undetected. | Photo: Stephanie L. Church/The Horse

The Canadian Animal Health Surveillance System reported a case of equine herpesvirus myeloencephalopathy (EHM), the neurologic form of equine herpesvirus-1 (EHV-1), the Equine Disease Communication Center (EDCC) said July 13.

“An unvaccinated 19-year-old Quarter Horse gelding presented with hind end ataxia with no improvement on anti-inflammatory treatment,” the EDCC said. “The index case tested negative on PCR but showed a high antibody titer for EHV-1/4 on ELISA. The other six horses on the premises tested negative and none have been moved off the premises since the diagnosis was made; however, the positive horse was present at a roping/rodeo event in Alberta just prior to diagnosis.”

The EDCC said the exact event the EHM-positive horse attended is currently unknown