Three mosquito pools in York County and an emu in Cumberland County have tested positive for Eastern Equine Encephalitis, according to the Maine Center for Disease Control and Prevention.

Emus are large, flightless birds that are sometimes raised as livestock.

The CDC last week announced a mosquito pool in York tested positive for EEE. State health officials say people should protect themselves from mosquito bites, though it is rare for humans to be infected with the virus.

Last year, Maine identified EEE in three horses, one emu, one pheasant flock and 26 mosquito pools.

The EEE virus is carried by mosquitoes that pick it up from infected wild birds. Horses, llamas and emus can be protected from EEE through vaccination.

The emu that tested positive in Cumberland County was not vaccinated, according to state veterinarian Dr. Michele Walsh.

“It is important for people to understand that the only way a human can get EEE is from a bite from an infected mosquito,” she said.

Dr. Sheila Pinette, director of the Maine CDC, cautioned Mainers to protect themselves against mosquito bites by wearing long sleeves and long pants, using bug repellent and draining sources of standing water in yards. She also said horses, llamas and emus should be vaccinated.

There has never been an identified case of EEE in a Maine resident. The only human case was reported in New Hampshire.

EEE can cause illness in people that in rare cases can be fatal. There is not a specific treatment.

Symptoms include a high fever, severe headache, stiff neck and sore throat. The virus can occasionally cause seizures and coma.

Physicians and public health officials urge the use of bug spray, especially at dawn and dusk, as well as wearing long-sleeved or other protective clothing to prevent bites. Mainers also are advised to get rid of standing water where mosquitoes breed.