WNV Positive Mosquito Sample & Risk Level Change in the Greater Boston Communities

8/5/21 WNV positive mosquito samples and risk level changes for Greater Boston Communities

The following cities and towns have had WNV positive mosquito sample(s): Arlington, Cambridge, Everett, Boston. Given the sustained and increasing WNV activity in the Boston area, WNV risk levels are being increased to Moderate for Arlington, Everett, Malden, Medford, and Somerville. Heavy precipitation events have increased the main WNV vector species Culex pipiens abundance in the Greater Boston area. Abundance levels for Culex WNV vector species are expected to continue to trend up in the comping weeks. Recommended public health measures include raising awareness among residents, reminding residents to use mosquito repellents with an EPA-registered active ingredient and observing peak mosquito activity at dusk and dawn. MDPH will continue enhanced surveillance activities in this region. 

Although Framingham was not identified specifically in the update, we still "may" expect to see increases in test samples. It is imperative to use insect repellants when engaging in outdoor activities especially at dusk and dawn hours.