Locally Acquired West Nile Virus Detected in Maine Resident for the First Time Since 2020: Maine CDC

The Maine Center for Disease Control and Prevention (Maine CDC) announced on Tuesday that a Maine resident has tested positive for West Nile Virus (WNV), a case which the agency says is the first locally acquired infection in Maine since 2020.

WNV, like the Eastern Equine Encephalitis virus (EEE) and Jamestown Canyon virus (JCV), are viruses spread though the bite of an infected mosquito. The viruses cannot be spread form human to human or from human to animal.

Infection with all three viruses usually starts with flu-like symptoms in humans, and can in severe cases develop into brain swelling (encephalitis) and spinal cord inflammation (meningitis), according to the Maine CDC.

About one in every 150 people infected with WNV may develop a serious, sometimes fatal illness, and recovery for survivors can take weeks to months, with some people experiencing lifelong impacts to their health.

In their Tuesday press release, the Maine CDC said the case of WNV was found in a Cumberland County resident in their 40s, with no history of recent travel outside of the state.

This has led health officials to believe the virus was contracted locally, which would make it the first instance of locally acquired WNV in a Maine resident since 2020, and the second case of WNV in a Maine resident detected this year.

Sor far this year, the Maine CDC has reported the following cases of mosquito-borne diseases in animals in the state:

• EEE in 4 horses, 2 emus, 1 llama, and 1 wild turkey;
• JCV in 4 mosquito pools (groups of up to 50 mosquitoes regularly tested as part of routine surveillance);
• WNV in 15 wild birds.

Due to the recently detected cases of infection, the Maine CDC says that Cumberland, Kennebec, Penobscot, Somerset and Waldo counties are currently “high risk,” and all other counties are at an “elevated risk” at this time.

The Maine CDC says the risk of mosquito bites is highest from dusk to dawn and when temperatures are above 50°F, when mosquitos are most active and biting.

The agency urged anyone experiencing flu-like symptoms, severe headaches, behavior changes, or serious drowsiness, to call a health care provider, especially if a COVID-19 test is negative.

“One person has now tested positive for locally acquired WNV and four domestic animals tested positive for EEE just last week,” Maine CDC Director Dr. Puthiery Va said Tuesday. “Maine people know that mosquitoes are a nuisance, but we want people to be aware that they can also potentially lead to serious consequences for your health.”

“Whether mowing the lawn, walking the dog, or enjoying a meal outside, we want all Maine people to remember to take precautions against mosquito bites whenever you go outside,” Va said.

Maine CDC recommended that Maine residents apply insect repellent when outdoors, to wear long sleeves, long pants and socks to help reduce mosquito bites, and to be aware of peak mosquito hours.

Residents are also advised to make use of insect screens on windows and doors, and to drain any standing water in rain gutters, drains, flowerpots and birdbaths, as mosquitoes lay their eggs in standing water.