Massachusetts public-health guidance focuses on preventing mosquito bites and reducing standing water around the home, because WNV and EEE activity varies by place and over the season.
West Nile virus
Massachusetts monitors WNV during mosquito season. About 80% of infected people have no symptoms; about 20% develop a febrile illness, and fewer than 1% develop neuroinvasive disease such as meningitis or encephalitis.
Eastern equine encephalitis
EEE is rare but can be severe. CDC reports that most infected people have no symptoms; severe illness can involve meningitis or encephalitis and may cause long-term complications or death.
What about dengue, Zika and chikungunya?
Massachusetts DPH notes that dengue, Zika and chikungunya are mosquito-borne diseases people may be exposed to when traveling in other regions of the world. WNV and EEE are the mosquito-borne viruses that occur in Massachusetts.
Reduce bites.
Use EPA-registered repellent as directed, wear protective clothing when appropriate, and keep window and door screens in good repair.
Reduce water.
Once a week, empty, scrub, turn over, cover or discard items that hold standing water. Small containers can produce mosquitoes too.
Risk changes during the season.
Massachusetts conducts seasonal WNV and EEE surveillance, including routine mosquito testing and human-case tracking. Current risk maps and testing data are updated during the June–October surveillance season, so homeowners should check the state’s current arbovirus update for local conditions.
Start with the yard.
The companion homeowner guide shows the water-holding items and property conditions worth checking every week.
See the Mosquito Prevention GuidePublic-health sources
Fact-checked against current Massachusetts DPH and CDC guidance on September 14, 2026.
Massachusetts DPH: Mosquito-borne Diseases · Massachusetts DPH: Current WNV & EEE Risk · CDC: West Nile Virus · CDC: Eastern Equine Encephalitis · Massachusetts DPH: Mosquito Prevention