Photo: Mosquitos transit West Nile virus so keep them away (Image by mika mamy from Pixabay) 

Massachusetts’ public health agency has named Belmont as a “high risk” community for infection from the West Nile virus.

On Tuesday, Sept. 10, Massachusetts Department of Public Health announced three additional human cases of West Nile virus in Massachusetts in the past week, bringing the total year-to-date number of 10.

As a result, WNV risk levels were raised to high in Belmont, Arlington, Malden, Medford, and Melrose in Middlesex County; Chelsea, Revere, and Winthrop in Suffolk County, and Saugus in Essex County.

WNV is usually transmitted to humans through the bite of an infected mosquito. There were six human cases of WNV and no animal cases in 2023. No animal cases of WNV have been detected so far this year.

“The risk of West Nile virus in Massachusetts will continue until the first hard frost. While the temperatures may be a bit cooler, September is still within the peak time for West Nile virus activity in Massachusetts,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “As we all adjust to our post-summer schedules, one routine that everyone should continue is using mosquito repellent when outdoors.”

There have been 286 WNV-positive mosquito samples so far this year detected from Barnstable, Berkshire, Bristol, Dukes, Essex, Hampden, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties.

People have an important role to play in protecting themselves and their loved ones from illnesses caused by mosquitoes.

Avoid Mosquito Bites

Apply Insect Repellent when Outdoors. Use a repellent with an EPA-registered ingredient, such as DEET (N,N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), or oil of lemon eucalyptus (p-menthane-3,8-diol (PMD) or IR3535) according to the instructions on the product label. DEET products should not be used on infants under two months of age and should be used in concentrations of 30 percent or less on older children. Oil of lemon eucalyptus should not be used on children under three.

Be Aware of Peak Mosquito Hours. The hours from dusk to dawn are peak biting times for many mosquitoes. Consider rescheduling outdoor activities that occur during evening or early morning in areas of high risk.

Clothing Can Help Reduce Mosquito Bites. Wearing long sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

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 that hold water. Check rain gutters and drains. Empty unused flowerpots and wading pools and change the water in birdbaths frequently.

Install or Repair Screens. Keep mosquitoes outside by having tightly fitting screens on all windows and doors.

More information, including all WNV and EEE positive results, can be found on the Arbovirus Surveillance Information web page at Mosquito-borne Diseases | Mass.gov, which is updated daily, or by calling the DPH Division of Epidemiology at 617-983-6800.