Even though it might still be cold outside, mosquitoes will be here soon enough, and they'll be spreading two diseases among horses that can be eliminated by vaccination: Eastern equine encephalitis (EEE) and West Nile virus (WNV).
"Before we see our first mosquito it’s easy to forget about vaccinations against mosquito-borne diseases,” said Wisconsin state veterinarian Paul McGraw, DVM. “We’ve already seen the sun emerge to warm things up and the mosquito population will multiply before you know it."
Horses require two doses of the vaccinations initially and then boosters at least annually.
"Work with your veterinarian on your horse’s vaccination program, so you get the best formulation for your horse and advice about additional boosters later in the season," McGraw said.
Both WNV and EEE are caused by viruses transmitted by mosquitoes, and both can cause encephalitis (inflammation of the brain) and prove fatal to horses. Clinical signs are similar for both diseases and include depression, appetite loss, drooping eyelids and lower lip, fever, weakness, twitching, paralysis, lack of coordination, aimless wandering, circling, and blindness.
Neither of the viruses is contagious between horses. While humans can also be infected by both WNV and EEE, it does not pass between people and horses. Mosquitoes biting warm-blooded animals is the only route of transmission.