Officials from the Massachusetts Department of Agricultural Resources (DAR) are advising horse owners to plan “spring shots” with their veterinarians to ensure proper protection from mosquito-borne diseases like West Nile virus (WNV) and Eastern equine encephalitis (EEE).

“It is important to stay a step ahead of these diseases and administering vaccinations in a timely manner is the best way to protect our equine population,” said DAR Commissioner John Lebeaux. “The timely use of these preventative measures are a benefit to both horses and horse owners and ensure a safe and healthy equine population across the Commonwealth.”

There were zero cases of WNV or EEE in 2015, however, DAR reminds horse owners that annual vaccinations should be administered early to ensure their animals are protected prior to the peak arboviral season beginning in late July and August. Owners are urged not to wait until positive cases are reported in their area, since it can take several weeks for an animal to be fully protected by a vaccine.

Both WNV and EEE pose serious risks to horses and other equids. A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes. Clinical signs of EEE include moderate to high fever, depression, lack of appetite, cranial nerve deficits (facial paralysis, tongue weakness, difficulty swallowing), behavioral changes (aggression, self-mutilation, or drowsiness), gait abnormalities, or severe central nervous system signs, such as head-pressing, circling, blindness, and seizures. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care; fatality rates reach 75-80% among horses. Horses that survive might have long-lasting impairments and neurologic problems