Horses that have been vaccinated in past years will need an annual booster shot. | Photo: Anne M. Eberhardt/The Horse

As a result of heavy rains and increased mosquito populations, the Maryland Department of Agriculture is strongly encouraging horse owners to make sure their equids are vaccinated against West Nile virus and Eastern equine encephalomyelitis, two potentially fatal diseases spread by mosquitoes.

“With all of the rain the region has experienced and with mosquito season now in full swing, it is important that horse owners are being proactive and vaccinating their equines against mosquito-borne diseases,” said Maryland State Veterinarian Michael Radebaugh, VMD. “We urge horse owners to speak with their veterinarians about vaccinations, and also remind veterinarians throughout the state of Maryland to report any cases of equine arboviruses to the department.”

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