09/04/2025
Message from the Board of Health:
View News Flash on Town Website: https://www.marionma.gov/CivicAlerts.aspx?AID=249
State Health Officials Announce Season’s Second Human Case of West Nile Virus in Massachusetts
WNV risk levels elevated in 10 additional communities
Wednesday, September 3, 2025
BOSTON – The Massachusetts Department of Public Health (DPH) today announced the second human case of West Nile virus (WNV) in Massachusetts this year in a woman in her 60s who was exposed in Essex County.
This follows yesterday’s announcement of the first confirmed WNV infection in a person this season. As a result of these two cases and ongoing evidence of WNV in mosquitoes, risk levels have been elevated to high in Belmont, Cambridge, Everett, Malden, Melrose, Revere, Saugus, Somerville, Wakefield, and Watertown.
“Massachusetts is in peak season for the spread of West Nile virus,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “While the temperatures have dropped slightly, this is the time of year when most people get exposed to the virus. We encourage everyone to use mosquito repellent, to wear clothing to reduce exposed skin, and to empty anything that may be collecting water outside your home.”
The first WNV-positive mosquitoes in the state this year were announced on June 17. Since then, 364 mosquito samples have tested positive for WNV so far this season from Barnstable, Berkshire, Bristol, Dukes, Essex, Franklin, Hampden, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties. There has also been one animal case of WNV this year in a goat.
The risk for WNV is now high in 20 municipalities in Suffolk, Middlesex, and Essex counties and moderate in 183 cities and towns in Barnstable, Berkshire, Bristol, Essex, Franklin, Hampden, Hampshire, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties.
In addition to WNV, Eastern equine encephalitis (EEE) has also been detected in mosquitoes in Massachusetts this year. There have been 21 EEE-positive mosquito samples and no human or animal cases so far this year.
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 years of age.
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.
Protect Your Animals
Animal owners should reduce potential mosquito breeding sites on their property by eliminating standing water from containers such as buckets, tires, and wading pools – especially after heavy rains. Water troughs provide excellent mosquito breeding habitats and should be flushed out to reduce mosquitoes near paddock areas. Horse owners should keep horses in indoor stalls at night to reduce their risk of exposure to mosquitoes. Owners should also speak with their veterinarian about mosquito repellents approved for use in animals and vaccinations to prevent West Nile virus (WNV) and EEE. If an animal is suspected of having WNV or EEE, owners are required to report to the Department of Agricultural Resources, Division of Animal Health by calling 617-626-1795, and to the Department of Public Health by calling 617-983-6800.
Learn more about mosquito-borne diseases, including all WNV- and EEE-positive results on DPH’s Arbovirus Surveillance Information page, which is updated daily, or by calling the DPH Division of Epidemiology at 617-983-6800.
https://www.mass.gov/mosquito-borne-diseases
