Pasco County is on alert for eastern equine encephalitis after two horses recently tested positive for the mosquito-borne illness.
The county health department said the horses were in east and central Pasco.
Although the disease is not spread by person-to-person contact, its presence in horses could mean people in the area are also at risk.
The disease in humans is rare and caused by a virus spread by infected mosquitoes. It is one of a group of mosquito-transmitted viruses that can cause encephalitis, an inflammation of the brain.
Those at highest risk are people who live in or visit wooded areas and people who work or play outdoors. Symptoms may include headache, fever, dizziness, confusion, movement disorders and coma.
Health officials reminded people to avoid the outdoors at dusk and dawn, wear clothes that cover most of their skin, use a repellent that contains up to 30 percent DEET, and eliminate standing water.
While there is no vaccine for humans, horse owners should contact their veterinarians about vaccines for horses, according to the health department.
For information, visit doh.state.fl.us/environment/medicine/arboviral/index.html or call the local county health department at (352) 521-1450, option 6.