Maine CDC Warns of Mosquito-Borne Virus Identified in Three Additional Counties

Sep 23, 2024

Maine people and visitors urged to protect themselves during high-risk mosquito season

AUGUSTA-- The Maine Center for Disease Control and Prevention (Maine CDC) announced today four wild birds tested positive for West Nile virus (WNV) in three new counties -- Piscataquis, Sagadahoc, and Washington. An alpaca also tested positive for WNV in Lincoln County, where a prior case of WNV was detected in a bird earlier this summer.

Mosquito pools in Penobscot County have now tested positive for Eastern Equine Encephalitis virus (EEE) and in Waldo County, they have tested positive for WNV. These are the first mosquito pools to test positive for either virus this year. A mosquito pool is a group of up to 50 mosquitoes collected through routine surveillance. Maine has had mosquito-borne disease activity in 13 of its 16 counties this season. Already this year, the Maine CDC has reported:

• EEE in 4 horses, 3 wild birds, 2 emus, 1 llama, and 1 mosquito pool
• WNV in 33 wild birds, 1 alpaca, 1 mosquito pool, 2 people -- one locally-acquired case and one travel-related case
• Jamestown Canyon virus (JCV) in 4 mosquito pools

EEE, WNV, and JCV - collectively known as arboviruses - spread through the bite of an infected mosquito and can infect humans and some animals. The viruses cannot spread from human to human, or from human to animal. Many infected people have no symptoms. However, mosquito-borne illnesses can be serious and sometimes fatal. About one in three people who show symptoms of EEE die and many who recover experience long-term neurological impacts.

"With 13 out of our 16 counties showing the presence of mosquito-borne disease activity, Maine people and visitors should be extra vigilant about taking protections whenever you go outside," saidMaine CDC Director Puthiery Va. "EEE, WNV, and JCV can have devastating effects on your health. We urge you to take simple steps to prevent mosquito bites, wherever you are in Maine, especially during this high mosquito-activity, high-risk time."

Mosquito-borne illnesses usually start with flu-like symptoms. Severe symptoms can include brain swelling (encephalitis) and spinal cord inflammation (meningitis). If you experience flu-like symptoms, severe headache, behavior changes, or serious drowsiness, call a health care provider, especially if a COVID-19 test is negative.

Every time you go outside, consider taking these steps to protect yourself from EEE, WNV, and JCV:

Protect yourself and your loved ones

• Use an EPA-approved repellent on skin and clothes. This includes ingredients like DEET, IR3535, picaridin, or oil of lemon eucalyptus. Always follow the instructions on the label.
• Pre-treat clothing with permethrin according to the label instructions.
• Children should not handle repellents. Instead, adults should apply repellents to their own hands first and then gently spread on the child's exposed skin. Avoid applying directly to children's hands. After returning indoors, wash your child's treated skin and clothing with soap and water or give the child a bath.
• Take extra precautions at dusk and dawn when mosquitoes are most active.
• Wear long sleeves, long pants, and socks.

Protect your home from mosquitoes

• Drain artificial sources of standing water around the home. This could include children's toys, bird baths, tires, and unused flowerpots. Any standing water provides great habitat for mosquitoes to lay eggs.
• Use screens on windows and doors and make sure any holes are patched.

Protect your animals

• Talk to your veterinarian about vaccines for EEE and WNV and repellents to protect livestock and horses. Vaccination is highly effective in horses that are kept up to date.
• Change the water in pet water bowls, buckets, and water troughs at least once each week. This will limit areas where mosquitoes can breed.

For more information:

• Mosquito Surveillance Reports
• Arboviruses & Maine Livestock
• Frequently Asked Questions
• Learn About Repellents