Mosquitoes Test Positive For West Nile Virus In West Haven

WEST HAVEN, CT — The Connecticut Mosquito Management Program has confirmed the presence of West Nile virus in mosquitoes collected from a testing site on Thill Street in West Haven, marking the first positive ID of the virus in the city this season, officials announced Wednesday.

“West Nile virus is primarily spread through the bite of an infected mosquito,” according to a news release from the City of West Haven Health Department. “While many who contract the virus do not exhibit symptoms, some individuals may experience severe illness. Common symptoms of WNV include fever, headache, body aches, joint pains, vomiting, diarrhea, and rash. In severe cases, the virus can lead to encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). Individuals over the age of 60 and those with weakened immune systems are at greater risk for serious complications.”

Read more from the news release below:

Beginning June 9, 2025, the West Haven Health Department continues its annual mosquito control program to help prevent human cases of West Nile Virus and other mosquito-borne illnesses. The program includes:

• Placing Bacillus thuringiensis israelensis (Bti) briquets in mosquito breeding sites on publicly owned properties
• Deploying FOURSTAR Sustained Release 90 Day Microbial Briquets in municipal catch basins containing standing water
• Responding to citizen complaints regarding mosquito activity

These larvicidal agents help reduce mosquito populations, especially in catch basins, which are the preferred breeding sites for the mosquito species known to transmit West Nile Virus.

Insect repellent is distributed through the Senior Center, prioritizing senior citizens who are at risk of developing severe illnesses from West Nile Virus. Repellent is also available at City offices that interact directly with the public and is promoted through an educational campaign.

This initiative is carried out in collaboration with the State of Connecticut Department of Public Health, the Connecticut Agricultural Experiment Station, and other relevant City departments.

"We urge all residents to take the necessary precautions to protect themselves and their families from mosquito bites," said Sheila Carmon City of West Haven Director of Health. "Simple measures such as using insect repellent, wearing protective clothing, and eliminating standing water can significantly reduce the risk of infection."

Precautions to Reduce West Nile Virus Infection Risk

Use Insect Repellent:

• Apply insect repellent according to product label instructions.
• If using sunscreen, apply sunscreen first and insect repellent second.

Protect with Clothing:

• Wear long-sleeved, light-colored, and loose-fitting clothing.
• Use hats when outdoors.

Control Mosquitoes Outdoors:

• Once a week, empty or discard items that hold water (e.g., vases, flower pot saucers).
• Tightly cover water storage containers.
• For containers without lids, use mesh with holes smaller than an adult mosquito.
• Use larvicides to treat large containers of water that cannot be covered or dumped.
• Repair cracks or gaps in septic tanks.
• Cover vent or plumbing pipe openings with mesh.

Control Mosquitoes Indoors:

• Keep windows and doors shut and use air conditioning.
• Install or repair window and door screens if possible.

Protect Babies and Children:

• Always follow instructions when applying repellent to children.
• Do not use insect repellent on babies younger than 2 months old.
• Dress children in clothing that covers their arms and legs.
• Cover strollers and baby carriers with mosquito netting.
• Do not apply insect repellent to a child's hands, eyes, mouth, cuts, or irritated skin.

No human cases have been reported with WNV-associated illnesses acquired in West Haven, and the risk level remains low at this time.

The Connecticut Mosquito Management Program will continue to monitor and manage mosquito populations in the area. Residents are encouraged to stay informed about WNV activity and follow recommended guidelines to protect themselves and their families.

For more information on West Nile virus and mosquito control, please visit the Connecticut Department of Public Health’s website here or contact the West Haven Health Department.

For FAQs regarding WNV, please visit the Connecticut Mosquito Management Program website here.