Mass. sees first human case of West Nile virus of 2025

Local News

A 70-year-old woman was the first in Massachusetts to test positive for West Nile virus this year, the Department of Public Health said Tuesday. 

A 70-year-old woman became the first in Massachusetts to test positive for West Nile virus this year, the Massachusetts Department of Public Health said Tuesday. 

The woman was exposed to the disease in Middlesex County, officials said.

The department did not disclose details about specifically where or when the woman was exposed. 

The mosquito-borne virus can be transmitted to humans through mosquito bites, the department said. 

The first mosquitos positive for West Nile virus were announced June 17, found in Boston’s West Roxbury and Hyde Park neighborhoods. 

Officials warned residents in early August about the rise of the virus, declaring the risk to be “high” in 10 Massachusetts communities.

The current risk for the virus is high in 10 municipalities in Suffolk and Middlesex counties, the department said. 

This season, there have been 319 West Nile-positive mosquito samples so far, the department said. In July, a goat in Lunenburg was the first animal to be infected with the virus in 2025. 

 “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,” said Public Health Commissioner Robbie Goldstein. 

Officials warned residents to be wary of the mosquitos, and take proper precautions like applying insect repellent when outdoors, draining standing water, and installing or repairing window screens. 

“The mosquitoes will be with us until the first hard frost,” said State Epidemiologist Dr. Catherine M. Brown. “People should use mosquito repellent with an EPA-registered active ingredient, clothing to reduce exposed skin, and consider rescheduling outdoor activities that occur during the evening or early morning.”

There were 19 cases reported in 2024 and six cases in 2023, according to the department.