West Nile virus found in Medford mosquito sample

A researcher held a cattail mosquito for inspection.
A researcher held a cattail mosquito for inspection.Pat Wellenbach/Associated Press

A mosquito sample collected in southeast Medford has tested positive for West Nile virus, city officials said Thursday night, stressing that there is no elevated risk of exposure to the virus for residents.

Medford uses a contracted service to trap mosquitoes for testing by the Massachusetts Department of Public Health, which confirmed the positive result to Medford health officials, the city said in a statement.

This marks the second positive test for the virus among mosquitoes in Massachusetts this year, officials said. On Tuesday, the Boston Public Health Commission reported that West Nile had been detected in a mosquito sample gathered last week in Brighton.


There is no vaccine for the rare mosquito-borne virus. It can cause fever and other flu-like symptoms, which are more likely to be serious in people over age 50, though most people infected do not get sick.

Medford officials asked residents to use mosquito repellents containing active ingredients approved by the US Environmental Protection Agency, to limit outdoor activities between dawn and dusk, to cover their skin with long sleeves and long pants when outdoors, to make sure screens fit tightly, and to reduce standing water near their homes where mosquitoes could lay eggs.

Jeremy C. Fox can be reached at jeremy.fox@globe.com. Follow him on Twitter @jeremycfox.