A horse that died in the town of Morristown is the first case of Eastern equine encephalitis in New York state this year.
The horse died Monday. The county announced the news Thursday after lab results came back.
Although the mosquito-borne virus is rarely transmitted to people, it has caused three human deaths over the last three years in Central New York, including a child in Oswego County last year.
EEE also caused the death of a horse in Massena last year.
Dry weather this year has probably reduced the mosquito population, but those that survive could prove deadly.
Obviously, now we have mosquitoes in the county with the virus, said Public Health Director Susan J. Hathaway. People need to take precautions. If you have a horse, be sure to vaccinate it. There are no human vaccines.
Infected people may have a range of symptoms, from a mild, flu-like illness to more serious complications such as seizures and a coma. A third of the people who contract EEE die, Ms. Hathaway said.
Mosquitoes carrying West Nile virus also have been found in the state, although the greatest risk areas are in New York City and on Long Island.
People should protect themselves when outdoors by using insect repellent containing DEET, picaridin or oil of lemon eucalyptus and by wearing pants and long sleeves. Insect repellents containing oil of lemon eucalyptus should not be used on children younger than 3 and products containing DEET should not be used on infants younger than 2 months. For children older than 2 months, the American Academy of Pediatrics recommends products containing 10 to 30 percent DEET.
Free treatments to rid areas of standing water such as pools or ornamental ponds are available from the county Soil and Water Conservation District, which is open from 8 a.m. to 4:30 p.m. Monday through Friday at 1942 Old DeKalb Road in Canton.
The county started with 19 cases of the larvicide and has five left, said manager Dawn C. Howard.
Standing water, such as in old tires, should be dumped when possible.