State public health officials have detected Eastern equine encephalitis in mosquitoes in York County, marking the first confirmed presence of the potentially fatal disease in Maine this year.

A batch of mosquitoes at a collection site in Alfred tested positive for EEE on Aug. 9, according to a health alert issued Monday by the Maine Center for Disease Control and Prevention. The mosquitoes were collected on July 16, making this the earliest in the season that Maine has identified the presence of the virus.

In 2012, a flock of 30 farm-raised pheasants in Lebanon died from Eastern equine encephalitis. The state also recorded its first-ever human case of West Nile virus, another infection spread through the bite of an infected mosquito, in a Cumberland County man.

EEE is rarer than West Nile, but more deadly. The virus can cause inflammation of the brain and leads to death in 35 percent to 50 percent of cases. Last fall, a Vermont man died of EEE.

EEE has not been detected in humans in Maine. It reappeared in the state after killing a number of horses in 2009.

West Nile has yet to appear in Maine this summer, but seven mosquito pools tested positive for the virus last year.

Other New England states have detected EEE and West Nile this summer. A New Hampshire man contracted two related viruses never before seen in the state — Powassan virus, which is transmitted through a tick bite, and Jamestown Canyon virus, a mosquito-borne pathogen that circulates widely in North America but doesn’t typically sicken humans.

Maine CDC recommends the following preventive measures to protect against EEE, West Nile virus and other mosquito-borne illnesses:

• Avoid spending time outdoors at dawn and dusk when many species of mosquitoes are most active.

• Use an EPA-approved repellent when outdoors, especially around dawn and dusk, and always follow the instructions on the product’s label.

• Wear protective clothing when outdoors, including long-sleeved shirts, pants and socks.

• Use screens on windows and doors to keep mosquitoes out of the home.

• Empty standing water where mosquitoes can breed, such as from flower pots, buckets and barrels.