CHATHAM – From the Town of Chatham: The Massachusetts Department of Public Health (MDPH) has confirmed that West Nile Virus (WNV) was detected in a mosquito sample collected in Chatham on August 18, 2026. This is the first detection of West Nile Virus in Chatham since testing began.
As a result, MDPH has raised Chatham’s risk level for West Nile Virus from LOW to MODERATE.
Cape Cod Mosquito Control crews are treating catch basins and containers holding standing water in the area surrounding the positive sample.
Residents and visitors are encouraged to take precautions to prevent mosquito bites:
• Use an EPA-registered insect repellent and follow label directions.
• Wear long sleeves, long pants and socks when possible.
• Be especially cautious from dusk to dawn, when many mosquitoes are most active.
• Drain standing water around your home, including water in flowerpots, wading pools, gutters and other containers.
• Make sure window and door screens fit tightly and are in good repair.
West Nile Virus is most commonly spread to people through the bite of an infected mosquito. People of all ages can become infected, but people over age 50 are at greater risk of severe illness.
The Town of Chatham Health Department will continue to work closely with MDPH, Cape Cod Mosquito Control and other agencies and will share additional information as appropriate.
For more information about West Nile Virus and mosquito activity in Massachusetts, visit www.mass.gov/dph/mosquito.
