Summer’s first mosquitoes infected with West Nile Virus found in Boston

Boston health officials reported Thursday afternoon that for the first time this summer, a sampling of mosquitoes has tested positive for West Nile Virus. The mosquitoes were collected in Roslindale on June 20.

These are the first mosquitoes to test positive anywhere in Massachusetts this year. West Nile is usually transmitted to humans through the bite of an infected mosquito. No human cases of the virus have been reported so far. Six residents fell ill last year, according to the state Department of Public Health.

“It’s again the time of year when it’s not surprising to find mosquitoes infected with West Nile Virus in Boston,” said Dr. Anita Barry, director the Infectious Disease Bureau at the Boston Public Health Commission. “The recent combination of hot weather and rain may have contributed to West Nile appearing slightly earlier this year than in some previous years, and people should take some simple precautions to avoid mosquito bites.”

Advertisement - Continue Reading Below

Recommended precautions include using insect repellant when outside, especially from dusk to dawn when mosquites are more likely to be biting, and wearing long pants and long sleeves. Check window and door screens are in good repair, and to keep mosquitoes from breeding, empty standing water in such things as empty flower pots, kiddie pools, and garbage cans.

The virus poses low risk to people, the commission said. Still, the city has begun putting larvicide in catch basins to reduce the number of mosquitoes.

For more information on the virus, call the Boston Public Health Commission at 617-534-5611 or visit