The Greenwich Department of Health has issued a warning after mosquitoes in New Canaan and Easton tested positive for West Nile virus.

Officials are reminding residents to continuously clean pools and maintain any standing body of water on their property, such as lakes or even bird feeders, because that's most commonly where mosquitoes breed and lay eggs.

They also say it's important to make sure all screen doors and windows are intact and to wear bug spray during the hot summer days to prevent any bites that could lead to more serious complications.

"In most instances, it can be a mild illness if folks get it, from slight fever to nausea, but it can also lead to encephalitis and meningitis," says Michael Long, director of environmental services. "There have been cases of folks dying from it."

Greenwich in June started several initiatives to prevent the breeding and hatching of mosquito eggs.

Last year, the state tested about 200,000 mosquitoes and identified West Nile-positive mosquitoes in 30 towns, including Greenwich. There were three human cases of the virus last year in Connecticut.

Long says the highest risk of exposure lasts from August through September.

There have been West Nile-positive mosquitoes found in the state every year since 1999.