Vaccinating horses at the proper time of the year for Eastern Equine Encephalitis is critical to ensuring animal health and protection from the mosquito-carried disease. But, timing of those vaccinations is important. According to Michigan State University equine veterinarian Judy Marteniuk, horses vaccinated after late March should be protected, but those vaccinated prior to March should receive an EEE booster.
EEE is a vector disease, which means it cannot be transmitted from horse to horse. In EEE, Mosquitoes are the vectors, or carriers, that transmit the disease to horses, which can result in death. However, there is a caveat. Marteniuk says early foaling broodmares that were vaccinated early on should get a booster in order to provide protection to their foals. The vaccine should be effective for six to eight months.
Karen Waite, MSU Extension equine specialist, cautions that if you have a horse and are unsure of its vaccination history, you should revaccinate them to be sure they are protected. Marteniuk advises that any horse not vaccinated in the past one to two years should receive a booster two weeks after the initial vaccination, rather than waiting the usual three to four weeks according to routine vaccination protocol.