West Nile virus detected in Worcester mosquitoes, pesticide sprayings scheduled

WORCESTER, Mass. — The Massachusetts Department of Public Health (MDPH) announced today that West Nile virus (WNV) has been detected in mosquitoes in Worcester.

The mosquitoes were collected from a trap site. They are not the first to test positive for WNV in Worcester this summer.

The first positive detection of WNV in Boston came from Jamaica Plain back in July.

As of now, the Central Massachusetts Mosquito Control Project (CMMCP) plans to use pesticide trucks to spray the general area where WNV was reported on Thursday, Aug. 6.

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CMMCP is also tentatively scheduled to spray Worcester on Aug. 11, 18 and 25.

Currently, the city’s WNV risk level is moderate and there are no reported human cases.

Residents living in areas to be sprayed will be notified via email, social media and text.

They are advised to take certain precautions when pesticide is administered. This includes closing street-facing windows, turning off “outside air” settings on air conditioners, keeping pets and children inside, washing produce from home gardens and remaining inside during the application as well as 15-20 minutes after.

Additionally, they can opt out of having their property sprayed by following instructions posted to the Massachusetts Department of Agricultural Resources website.

To avoid mosquito bites, residents are advised to practice the “five Ds”:

DRESS in long sleeves. DEET is an effective insect repellent. DAWN and DUSK are mosquitoes’ most active periods. DRAIN water from containers weekly.

WNV can impact people of all ages, but those over 50 are at the highest risk for severe symptoms.

Nine human cases were reported in Massachusetts during 2025.

The Worcester Division of Public Health works closely with MDPH and will follow their regular case management should one occur.

This is a developing story. Check back for updates as more information becomes available.

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