Maine State Veterinarian Dr. Don Hoenig today alerted veterinarians, horse owners and breeders to the potential exposure of five Maine horses to equine herpes virus, type 1 (EHV-1). The five horses, which are located on farms in the towns of Limington, Lyman and Buckfield, have been quarantined and have all been examined by the farms’ practicing veterinarian. None of these animals are currently exhibiting signs of EHV-1 but they are being closely monitored. These horses were imported into Maine within the past week and were potentially exposed to EHV-1 in New Jersey. The New Jersey State Veterinarian announced yesterday that two farms were under quarantine in that state for possible infection with EHV-1. On the New Jersey farms, one horse tested presumptively positive and three horses have been euthanized with clinical signs consistent with the neurological form of the disease.

EHV-1 is a contagious disease of horses which can cause severe neurological disease, abortion and death. Over the past several years, there have been numerous outbreaks of this disease at farms, stables and racetracks throughout the country. Maine’s last experience with EHV-1 occurred in 2007 when three horses died at a Rome stable.

The most common means of transmission of EHV-1 is by direct contact with infected horses through aerosol transmission of droplets from coughing or snorting. Additionally, mares who have aborted will shed the virus in vaginal fluids and aborted fetuses are also sources of virus. Respiratory shedding generally lasts for 7-10 days but may persist for somewhat longer. Depending on the weather (viruses survive well in the cold, the damp and the dark and don’t survive long under hot, dry, sunny conditions), the virus may persist in the environment for several weeks. Inanimate objects such as grooming tools, water and feed buckets and contaminated clothing or footwear can also be potential sources of spread. Therefore, all horse owners and people who conduct business on horse farms (feed trucks, farriers, veterinarians, sales people, etc.) should practice strict biosecurity. This includes changing outer clothing when traveling between farms, cleaning and disinfecting all equipment used when treating or handling horses and cleaning and disinfecting footwear or boots between farms.

For more information on the Maine situation, please call the Maine Department of Agriculture at 207-287-3701 to speak with either Dr. Hoenig or Dr. Beth McEvoy. For more information and regular updates on EHV-1, visit www.aphis.usda.gov/vs/hahss/equine/