A horse in Washington County, Florida, has recently tested positive for Eastern equine encephalitis (EEE), as confirmed by the Florida Department of Agriculture and Consumer Services. Unfortunately, the horse had to be euthanized.
This case marks the seventh confirmed EEE case in Florida for the year 2026.
EDCC Health Watch is a marketing program by Equine Network that utilizes information from the Equine Disease Communication Center (EDCC) to create and distribute verified equine disease reports. The EDCC is an independent nonprofit organization supported by industry donations to provide open access to infectious disease information.
EEE 101
Eastern equine encephalomyelitis is caused by the Eastern equine encephalitis virus, with wild birds serving as a natural reservoir. Mosquitoes that feed on EEE-infected birds can transmit the virus to humans, horses, and other birds. Horses do not reach high enough virus levels in their blood to be contagious to other animals or humans. Due to the high mortality rate in horses and humans, EEE is considered one of the most severe mosquito-borne diseases in the United States.
Tips for preventing mosquito-borne diseases include:
- Avoid mosquito bites: Use insect repellent when outdoors, especially from dusk to dawn.
- Look for EPA-labeled products containing active ingredients like DEET, picaridin (KBR3023), or oil of lemon eucalyptus (p-menthane 3,8-diol).
- Apply more repellent as needed, following label instructions, if mosquitoes become active.
- Mosquito-proof homes: Repair or install window and door screens, and cover or remove containers with standing water where mosquitoes can breed.
- Protect your horses: Veterinarians recommend using licensed vaccines against EEE for all U.S. horses. Horses should be vaccinated at least once a year (frequency may vary in high-risk areas). It is not too late in the year to vaccinate your horses.
- Use approved insect repellents to safeguard horses.
- If possible, keep horses indoors during peak mosquito hours of dusk and dawn.
- Remove standing water, empty water troughs, and buckets at least weekly.
- Introduce fish to water tanks that consume mosquito larvae (contact local mosquito control for help), or use mosquito “dunks” (solid “donuts” of Bacillus thuringiensis israelensis, safe for horses) found at hardware stores.