MANCHESTER, NH – The City of Manchester Health Department announced today that one batch of mosquitoes, collected in Manchester on August 27, 2025, has tested positive for Eastern Equine Encephalitis Virus (EEE). This is the first EEE positive mosquito batch identified in Manchester this year and the first since 2019. Additionally, there have been seven West Nile Virus (WNV) positive batches this season.
According to Anna Thomas, MPH, Manchester’s Public Health Director, “It is important for residents and visitors to take steps to prevent mosquito bites, as EEE and WNV can be transmitted to humans from the bite of an infected mosquito.
We recommend people use an EPA evaluated, effective mosquito repellant, avoid being outdoors at dawn and dusk, and remove standing water from around the home, where mosquitoes reproduce, to limit the risks of contracting these illnesses.”
Adult mosquitoes can be active through the first ‘hard frost’ of the season, so it is important that people continue to remain vigilant in eliminating mosquito-breeding areas and taking personal precautions.
The City of Manchester is currently at “MODERATE” risk level for mosquito-borne disease. The Manchester Health Department is continuing its mosquito surveillance activities into October and will keep the public informed about additional results.
If the risk level increases to “HIGH”, and in accordance with the NH Arboviral Illness Surveillance, Prevention and Response Plan, the Department is prepared to activate its Special Permit (issued by the NH Department of Agriculture) and work with our Mosquito Control Contractor to schedule the spraying for adult mosquitoes.
Symptoms of EEE virus often appear 4 to 10 days after being bitten by a mosquito carrying the EEE virus. People who get sick from EEE can develop illness, with symptoms including fever, headache, weakness, and muscle and joint pains. A more serious central nervous system infection can develop such as meningitis and encephalitis (inflammation of the brain).
EEE typically causes a more serious disease than WNV and carries a high mortality rate for those who contract the serious encephalitic form of the illness. There is no specific treatment for the disease.
If you, or someone you know, is experiencing these symptoms, please contact your health care provider.
Manchester residents and businesses can call the City of Manchester Health Department with concerns and questions about mosquito-borne illnesses at (603) 624-6466.
Prevention guidelines for EEE and WNV can be found below:
∙ Information on EEE and WNV are available on the NH DHHS Mosquito-Borne Illnesses website. ∙ For additional information, you can visit the Centers for Disease Control and Prevention Mosquitoes website.
Prevention Guidelines for West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE)
- Eliminate standing water and other mosquito breeding locations around your property. Please do not attempt to drain or alter natural waterbodies for mosquito control, since the New Hampshire Department of Environmental Services regulates the management of ponds and wetlands.
- Remove old tires, tin cans, plastic containers, ceramic pots, or other containers from your property
- Do not overlook containers that have become overgrown by aquatic vegetation ∙ Drill holes in the bottom of recycling containers that are left outside
- Ensure roof gutters are clean and draining properly
- Clean and chlorinate swimming pools and hot tubs
- Unmaintained swimming pools and hot tubs must be covered, ensuring covers are kept free of standing water
- Turn over wading pools when not in use
- Aerate garden ponds or stock with fish
- Turn over wheelbarrows and change water in birdbaths at least twice weekly ∙ Remind or help neighbors to eliminate breeding sites on their properties
Be aware of where mosquitoes live and keep them from entering your home.
- Weeds, tall grass, and bushes provide an outdoor home for adult mosquitoes
- Mosquitoes can enter homes through unscreened windows or doors or broken screens
- Make sure that doors and windows have tight-fitting screens
- Repair or replace damaged screens
Protect yourself from mosquito bites.
- Mosquitoes are most active and likely to bite at dawn and dusk
- If outside during this time, wear protective clothing such as long pants, long sleeved shirts, and socks
- Consider the use of an EPA evaluated, effective insect repellent. Common ingredients may include: DEET, Picaridin, oil of lemon eucalyptus, or IR3535
- Use all repellents according to the manufacturer’s directions
- Children should not apply repellent to themselves
- Vitamin B, ultrasonic devices, incense, and bug zappers have not been shown to be effective in preventing mosquito bites
SOURCE: City of Manchester Health Department