A horse from Deschutes County tested positive for Equine Herpesvirus (EHV-1) on May 4, 2022. Confirmation came from an out-of-state laboratory. The horse had recently attended the Oregon Horse Center at the Prairie Arena in Eugene from April 22-25. The horse has not attended any other events since that time. EHV-1 can cause upper-respiratory disease, neurological disease, abortions, and/or neonatal death. This horse showed neurological symptoms but did not show signs of nasal discharge or an elevated temperature. Unfortunately, due to delayed reporting, this case was only recently shared with the department.
A second horse from Deschutes County became symptomatic on May 13. The infected horse attended a show on May 6-7, also at the Oregon Horse Center in Eugene. Confirmation of EHV-1 came from the Oregon State University Oregon Veterinary Diagnostic Laboratory on May 16.
Both horses were humanely euthanized and both ranches are currently under quarantine. The required quarantine will last a minimum of 28 days.
Equine herpesvirus information
The EHV-1 virus is highly contagious and is spread via aerosolized secretions from infected coughing horses, by direct and indirect contact with nasal secretions, and fetal fluids. EHV-1 typically has an incubation period of 2-10 days. Respiratory shedding of the virus generally occurs for 7-10 days but may persist longer in infected horses.
Following basic biosecurity practices is an important factor in reducing risk of exposure to all contagious equine diseases. Basic biosecurity measures to follow to decrease potential disease spread at equine events include:
• Limit horse-to-horse contact.
• Limit horse-to-human-to-horse contact.
• Avoid use of communal water sources.
• Avoid sharing of equipment unless thoroughly cleaned and disinfected between uses.
• Monitor your horse for clinical signs of disease and report any temperature over 102°F to a veterinarian.
The above statement is from the Oregon State Veterinarian, Dr. Ryan Scholz.