The first and best defense against EEE and WEE is vaccination. The American Association of Equine Practitioners (AAEP) includes EEE/ WEE on its list of “core vaccines,” which are recommended for the majority of horses. A single formula protects horses against both EEE and WEE. The vaccine contains an inactivated adjuvanted whole virus, which means that it
contains whole viruses that have been rendered inactive, combined with an adjuvant, a substance that stimulates a greater immune response.
Your veterinarian can advise you on the most appropriate vaccination schedule for your horse. An adult horse who has never been vaccinated needs a two-dose series, four to six weeks apart, which needs to be completed before mosquitoes and other insect vectors are active for the season. An adult horse who has been previously vaccinated needs an annual booster prior to the start of mosquito season. In some cases---for horses with compromised immunity, for example, or those who live in areas where mosquitoes are active year-round---your veterinarian may recommend boosters every four to six months.
Changing water in larger troughs at least once a week will prevent any hatched mosquito larvae from reaching maturity.
Distribution of reported equine EEE cases in 2016 (116 total cases)