Two collections of mosquitoes in the Abbot Street area recently tested positive for Eastern Equine Encephalitis, or the EEE virus, town officials said.
A statement from the town said the mosquitoes tested were trapped on Aug. 13, and were of a species that is known to bite humans.
As a result of these positive tests, the Northeast Massachusetts Mosquito Control and Wetlands Management District placed a supplemental mosquito trap in the area, officials said. They said larvicide was also used.
Officials said the town's Board of Health planned to meet with a state entomologist to discuss the test results.
Mosquito spraying from truck-based applicators was planned for targeted areas this week.
Local health officials urge residents to follow these safety steps: be aware of peak mosquito hours, from dusk to dawn; cover up with long-sleeves, pants and socks; and wear mosquito repellent wtih DEET, permethrin, picaridin, IR3535 or lemon eucalyptus oil.
Many mosquitoes lay their eggs in standing water, so limiting the number of places around homes for mosquitoes to breed by either draining or getting rid of items that hold water is encouraged. Homeowners should check rain gutters and drains, empty any unused flowerpots and wading pools, and change water in birdbaths frequently.
According to the Centers for Disease Control and Prevention, the EEE virus is a rare cause of brain infections or encephalitis. Very few human cases are reported across the U.S. each year, but EEE can be fatal or leave victims with serious complications and neurological problems, the CDC reports.
The Andover EEE news follows similar findings in Pelham this week.
While no humans in Pelham have tested positive for the virus there, the New Hampshire Department of Health and Human Services identified batches of mosquitoes in that tested positive for EEE, according to Pelham Town Administrator Brian McCarthy.
Town officials said they planned to spray town fields, parks and schools to reduce mosquitoes in the area, according to McCarthy.
Those infected with the virus appear to have flu-like symptoms, including fever, headache, weakness, and muscle and joint pains, according to health officials.
Health officials say symptoms show up four to 10 days after a person is bitten by an infected mosquito.