Following an Equine Herpes Virus (EHV) outbreak in Europe with a death toll that has now reached 17, with additional positive tests relating to a third Spanish Tour, the Florida Department of Agriculture and Consumer Services confirmed two cases of the virus in what is believed to be a similar but unrelated outbreak at a boarding facility in Marion County this month.

Equine Herpesvirus myeloencephalopathy (EHM) is the neurologic form of equine herpes and may occur as isolated cases or an outbreak. EHV-1, the virus at issue in these outbreaks, is one of nine different such viruses that have been identified to date, and can cause neurologic disease, as well as respiratory disease and reproductive disease, including abortion and neonatal death. The virus does not affect humans.

Because EHV-1 is highly contagious among horses and can lead to death, the United States Equestrian Federation (USEF), the International Federation for Equestrian Sports (FEI), competition organizers, veterinarians, and government authorities are working to limit its spread.

For example, on March 12, 2021, FEI extended its shutdown of international events in mainland Europe through at least April 11, 2021, announcing that the Longines FEI Jumping World Cup Final and FEI Dressage World Cup Final in Sweden were canceled, as part of efforts to contain the virus. Recently, an additional 856 horses that participated in the Spring Mediterranean Tour in Oliva, Spain in February have been blocked on the FEI database from competitions.

USEF has stated it fully supports restrictive measures to limit the spread of the virus, and recommends the following best practices:

• Review and ensure you are prepared for quick implementation of an isolation plan at a competition grounds and/or at your home farm or facility.
   
• Check your horse’s temperature twice daily and maintain a temperature log.
   
• Isolate horses at first signs of symptoms or illness and contact your veterinarian immediately.
   
• Isolate any horses with a fever of about 101.5-102.5°F in separate facilitates on competition grounds or at separate veterinary facility off-site.
   
• Keep separate feed buckets, brushes, rags, and tack/equipment for each horse.
   
• Ask your veterinarian about appropriate sanitizing solutions.
   
• Eliminate communal or shared water troughs and buckets.
   
• Practice hand washing in between handling horses.
   
• Maintain social distancing for horses, including limiting nose-to-nose contact with other horses at the ring.
   
• Consult your veterinarian and ensure your horse is vaccinated for EHV (Rhinopneumonitis vaccine) in line with GR845. (Note that vaccination does not protect against EHM, but does reduce clinical signs and shedding of the virus, limiting potential spread.)

Similarly, the Florida Department of Agriculture and Consumer Services recommends horse owners consult with their equine veterinarian regarding the most appropriate use of vaccination in their particular circumstances, as well as best management practices, since latent infection can still pose problems. Biosecurity measures are critical to preventing the virus’s spread and can effectively break the transmission cycle.

After the second horse stalled immediately adjacent to the index horse was confirmed positive for EHV-1 on March 4, 2021 in Florida, immediate action was taken, including isolation and quarantine with a quick disease investigation. Since then, no new cases have been identified in the state.

The state of Florida’s quarantines and movement restrictions have been limited to the single farm in Marion County where the two affected horses were housed and, to date, the state has not formally imposed additional movement requirements or restrictions, though other states and venues have. The Florida Division of Animal Industry strongly recommends owners and trainers enact strict biosecurity measures for any horses that may have been stabled at the World Equestrian Center from Feb. 12, 2021, through Feb. 28, 2021. Florida also encourages all facilities to isolate horses importing into Florida from the affected regions in Europe.

EHM is a “reportable disease” in Florida. Suspected or confirmed cases of EHM must be reported immediately to the Florida State Veterinarian’s Office, by calling (850) 410-0900 from 8 a.m. to 5 p.m., Monday through Friday or, for after-hours reporting, call 1-800-342-5869 or email RAD@FDACS.gov.