"We are seeing a geographic expansion of West Nile virus activity to new towns in Connecticut," John Shepard, a medical entomologist at CAES, said. "We anticipate further build-up of West Nile virus in mosquitoes with increased risk of human infection from now through September."

A total of 48 mosquitoes have been captured and have tested positive for WNV so far this season in Connecticut.

The Connecticut Agricultural Experiment Station (CAES) has detected West Nile virus-infected mosquitoes in 19 cities and towns so far in 2025.