Mosquitoes have tested positive for West Nile virus in seven Connecticut towns, including Waterford.

Dr. Philip Armstrong, a medical entomologist working at the Connecticut Agricultural Experiment Station, or CAES, released a statement Wednesday with growing concern about the expansion of the West Nile virus in the state. Between July 15 and July 20, CAES identified infected mosquitoes in five towns: Darien, Greenwich, New Haven, Stamford, and Waterford. Earlier this year, infected mosquitoes also were identified in Milford and South Windsor.

There have been no human cases of associated illnesses yet this season, but with warm, humid weather, the conditions are ideal for mosquitoes to live and transmit the virus.

“We are beginning to see an expansion of West Nile virus activity in Connecticut,” Armstrong said in the release. “We anticipate further build-up of West Nile virus in mosquitoes with increased risk of human infection from now through September.”

CAES suggests that people use insect repellent and cover bare skin, especially at dusk and dawn when mosquitoes are most active. The Connecticut Mosquito Management Program website, portal.ct.gov/mosquito, offers more tips to avoid mosquito bites.