Public-health Officials Detect West Nile Virus in Massachusetts

BOSTON — On Friday, the Massachusetts Department of Public Health (DPH) announced that West Nile virus (WNV) has been detected in mosquitoes in Massachusetts for the first time this year. The presence of WNV was confirmed by the Massachusetts State Public Health Laboratory in a mosquito sample collected on July 6 in the town of Brookline in Norfolk County. No human or animal cases of WNV or Eastern equine encephalitis (EEE) have been detected so far this year.

“We often find the first evidence of WNV in mosquitoes at about this time every year,” Public Health Commissioner Dr. Robert Goldstein said. “We are asking people to start taking steps now to avoid mosquito bites. While WNV can cause serious illness, there are simple things that you can do to protect yourself and your loved ones.”

WNV is usually transmitted to humans through the bite of an infected mosquito. There were 10 human cases of WNV in 2022. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe disease. Most people infected with West Nile will have no symptoms. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur.

“With the recent rain and the warmer weather, mosquito populations will increase, and we will start to see more of them carrying WNV,” said Dr. Catherine M. Brown, state epidemiologist. “Use a mosquito repellent with an EPA-registered ingredient, wear clothing to reduce exposed skin, drain standing water, and repair window screens. We also encourage everyone to make it a habit to visit DPH’s mosquito-borne-disease webpages so you know when and where WNV activity is occurring.”