Update April 3, 2015
A Pennsylvania pony has tested positive for the equine herpesvirus myeloencephalopathy (EHM), a neurological disease caused by EHV-1. It competed at a Maryland horse show on March 15th, a week before it began showing symptoms, according to officials.
The Pennsylvania Department of Agriculture states the York County stable that houses the index horse is quarantined. A second farm in Adams County is also quarantined.
The Maryland Department of Agriculture confirms officials contacted trainers that had horses in the same division as the index case at the horse show, so they can monitor their horses. The end of the 21-day incubation period is on April 5th for those horses. To date, no horses from the competition have exhibited symptoms.
A horse that was reported to have a fever on March 29th tested negative for EHV-1.
Symptoms may include respiratory disease, abortion, and intermittent outbreaks of neurologic disease in horses. Symptoms that should alert horse owners to the possibility of neurologic EHV-1 infection include fever, weakness, incoordination, and urine dribbling or inability to urinate. Horses with these symptoms should be examined immediately by a veterinarian.
EHV-1 can be spread through various methods. Direct, horse-to-horse contact is a common route of transmission, but indirect transmission is also possible. This occurs when infectious materials are carried between infected and non-infected horses by people or inanimate objects such as buckets, tack, or trailers. Aerosol transmission can also occur when infectious droplets are inhaled. The source of infectious droplets is most often respiratory secretions.
Veterinarians recommend using proper biosecurity measures when attending equine events to help protect your horses from the potential spread of any illness:
· 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.
Last week, authorities in Michigan and Ohio announced cases of EHV-1 in their states. Several other states including Virginia, Oklahoma, Texas, and New Jersey have also had cases of EHV-1 or EHM this year.