State Health Officials Announce Season’s Second Human Case of West Nile Virus

BOSTON — The Massachusetts Department of Public Health (DPH) announced the second human case of West Nile virus (WNV) in Massachusetts this year. The person is a male in his 70s who was exposed in Middlesex County in an area known to be at moderate risk.

The first WNV-positive mosquitoes in Massachusetts this year were announced on July 2 from mosquito samples collected in Quincy. There has been a total of 145 positive mosquito samples so far this year detected from Barnstable, Berkshire, Bristol, Dukes, Essex, Hampden, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties. The risk of human infection with WNV is moderate in the Greater Boston area (Middlesex, Norfolk, and Suffolk counties) and in parts of Barnstable, Bristol, Essex, Hampden, Plymouth, and Worcester counties.

“Many parts of the country, including Massachusetts, are experiencing increasing WNV activity,” Public Health Commissioner Dr. Robbie Goldstein said. “We are in the peak time of the year when most people are exposed to West Nile virus in Massachusetts. Residents should continue to take precautions to avoid mosquito bites.”

WNV is usually transmitted to humans through the bite of an infected mosquito. There were six human cases of WNV in 2023. The first WNV human case this year was announced on Aug. 6 and was exposed in Hampden County. No animal cases of WNV have been detected so far this year.

“It is still summertime, and the risk from WNV is going to be elevated for some time,” State Epidemiologist Dr. Catherine Brown said. “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.”