Perhaps it slipped your mind earlier this year or maybe you thought the mild weather would hold them off, but the mosquitoes are swarming and could spread two diseases among horses. It’s not too late to vaccinate for prevention of Eastern equine encephalitis (EEE) and West Nile virus (WNV).
"The mild weather we’ve had may have lulled you into a false sense of security, but the mosquito population has exploded since the warm weather arrived and horses are at risk,” said Dr. Julie McGwin of the Wisconsin Department of Agriculture, Trade and Consumer Protection.
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," McGwin said.
Both WNV and EEE are caused by viruses transmitted by mosquitoes, and both may cause encephalitis, or inflammation of the brain. Both viruses can be fatal to horses. Symptoms are similar for both diseases: depression, appetite loss, drooping eyelids and lower lip, fever, weakness, twitching, paralysis or lack of coordination, aimless wandering, circling and blindness.
Neither of the viruses is contagious between horses. While humans may also be infected by both WNV and EEE, it does not pass between people and horses. Mosquitos biting warm-blooded animals is the only route of transmission.
Besides vaccination, McGwin recommends taking other steps to limit horses' exposure to mosquitoes once the weather warms up:
- Remove items from surrounding property that could collect stagnant water such as old tires, tin cans, plastic containers.
- Keep rain gutters clean and draining properly.
- Clean and chlorinate swimming pools, outdoor saunas and hot tubs, and drain water from pool covers.
- Turn wading pools and wheelbarrows upside down when not in use.
- Empty and replace water in birdbaths at least once a week.
- Consider keeping horses in the barn from dusk to dawn, when mosquitoes are most active.