City of Somerville Advisory: First human case of West Nile Virus confirmed in Massachusetts

On September 3, 2025, in Latest News, by The Somerville Times

As the risk of disease rises, continue to protect yourself from mosquito bites this season

The Massachusetts Department of Public Health (DPH) announced the first positive human case of West Nile Virus (WNV) confirmed in the state this year in a woman in her 70s who was exposed in Middlesex County. Today, Somerville had their risk level elevated to high risk for West Nile Virus. Residents should continue to take precautions to protect themselves against mosquito bites and mosquito-borne diseases, including WNV and Eastern Equine Encephalitis (EEE).

“West Nile virus can be a very serious disease and its presence in mosquitoes remains high right now in Massachusetts,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “While September brings cooler air and the return to school for many in the state, the risk from WNV is going to be elevated for some time. Residents should continue to take precautions to avoid mosquito bites.”

While WNV and EEE can infect people of all ages, people over 50 are at higher risk for severe WNV, and people under 15 are particularly vulnerable to EEE. WNV and EEE symptoms tend to include fever and flu-like illness. To get real time info on risk levels, check DPH’s risk level map.

DPH recommends the following precautions:

Avoid Mosquito Bites 

Apply insect repellent when you go outdoors. Use a repellent with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), IR3535, or oil of lemon eucalyptus [p-methane 3, 8-diol, (PMD)] according to the instructions on the product label. DEET products should not be used on infants under 2 months old and should be used in concentrations of 30% or less on older children. Oil of lemon eucalyptus should not be used on children under 3 years old. Permethrin products are intended for use on items such as clothing, shoes, bed nets, and camping gear and should not be applied to the skin.  
Clothing can help reduce mosquito bites. Although it may be difficult to do when it’s hot, wearing long sleeves, long pants, and socks outdoors will help keep mosquitoes away from your skin. 
Be aware of peak mosquito hours. The hours from dusk to dawn are peak biting times for many mosquitoes. When risk increases, consider rescheduling outdoor activities that occur during the evening or early morning. If you are outdoors and notice mosquitoes around you, take steps to avoid being bitten by moving indoors, covering up, and/or wearing repellant.

Mosquito-Proof Your Home 

Drain standing water. Mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by draining or discarding items holding water. Check rain gutters and drains. Empty unused flowerpots and wading pools, and frequently change the water in birdbaths. 
Install or repair screens. Keep mosquitoes outside by having tightly-fitting screens on your windows and doors.

Protect Your Animals 

Owners should also speak with their veterinarian about mosquito repellents approved for animal use and vaccinations to prevent WNV and EEE, if applicable.  
If an animal is suspected of having WNV or EEE, owners are required to report to the Department of Agricultural Resources, Division of Animal Health by calling 617-626-1795, and to the Department of Public Health by calling 617-983-6800.

For more information, go to mass.gov/dph/mosquito or call the Massachusetts DPH Epidemiology Program at 617-983-6800.