PORTLAND — State officials have found West Nile virus in mosquitoes in York County and are investigating a possible case in a human, as well as a potential case of eastern equine encephalitis.

Dr. Stephen Sears, Maine’s state epidemiologist, said Friday that tests on the two people who might have contracted the diseases “showed signs of positivity,” but the results still must be confirmed by the federal Centers for Disease Control and Prevention.

Sears said interviews with the two patients suggest that the possible case of West Nile virus might have been contracted out of state. He said both people appear to have regained their health.

Sears said he is barred from identifying either person because of patient confidentiality laws.

No person in Maine has ever had a confirmed case of West Nile virus. A Massachusetts man died of EEE, or Triple-E, in 2008, and it’s believed he got the disease while visiting Maine.

West Nile virus and EEE appear in birds or mosquitoes in most years in Maine. The finding that mosquitoes caught in a trap in York County on Thursday had West Nile virus represents the disease’s first confirmed appearance in the state this year.

Sears said both diseases have been particularly active in the country this year for reasons that aren’t clear, although they could be related to the weather.

Dr. Sheila Pinette, director of the Maine Center for Disease Control and Prevention, said the news of the virus being found in mosquitoes is a reminder that Mainers should minimize their exposure to mosquitoes.

It doesn’t mean that humans are likely to contract the diseases, she said. Pinette noted that the diseases were found in mosquitoes in Massachusetts and New Hampshire last year but no humans were found to be infected in those states.

West Nile virus has shown up in Maine in most years since 2000, the year after it first appeared in the United States, most likely coming from Africa in a migratory bird or a mosquito that crossed the Atlantic in a plane.

EEE is native to the eastern United States and was first identified in humans in the 1930s.

Both diseases are carried by birds and then transmitted to humans by mosquitoes. Symptoms include lethargy and fevers, although some people who contract the diseases don’t ever show symptoms.

Pinette said people should take precautions to avoid mosquito bites by limiting outdoor activities from dusk to dawn, avoiding swampy areas, using bug spray and mosquito nets if sleeping outdoors, and wearing long-sleeve shirts and long pants.

Sears suggested that people get rid of standing water in their yards, because that’s where mosquitoes breed.

“Be hypervigilant and be aware,” Pinette said.

Sears said state health officials will send out a reminder to doctors and other health care providers Monday, alerting them to the two potential cases in humans and suggesting they look for symptoms in patients.

He said that if the case of West Nile virus is confirmed, the state probably won’t take other steps because of the likelihood that it was contracted out of state.

Health care providers will be alerted if the EEE case is confirmed, he said, and the state will do more widespread testing of mosquitoes and use the case to heighten public awareness.

Responses such as aerial spraying to kill mosquitoes are left to individual cities and towns, he said.

“That’s sort of a last resort” because of environmental concerns, Sears said.

He also warned against overreaction, saying, “It’s important that we don’t overemphasize small bits of information.”

Staff Writer Edward D. Murphy can be contacted at 791-6465 or at:

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