The state Mosquito Management Program announced Friday that mosquitoes trapped in nine Connecticut towns have tested positive for West Nile virus.

Thus far this season, the Connecticut Agricultural Experiment Station has identified infected mosquitoes in Bridgeport, Darien, Easton, Hartford, Newington, Stamford, Stratford, West Harford and West Haven, the Connecticut Agricultural Experiment Station said in a news release. 

“We are seeing a marked increase in the number of mosquitoes carrying West Nile virus with recent expansion into new locations in Fairfield, Hartford, and New Haven counties,” said Philip Armstrong, medical entomologist at the experiment station.

“These increases are currently being driven by warmer temperatures and recent rainfall events which have created additional mosquito breeding sites," he said.

Theodore Andreadis, director of the experiment station, emphasized that "this is the most critical time of summer when virus activity reaches its peak in the mosquito population with increased risk of human infection."

No horses or humans have been reported with West Nile virus-associated illnesses acquired in Connecticut this season.

During 2015, 10 Connecticut residents developed West Nile virus-associated illnesses, including encephalitis and meningitis, none fatal, the experiment station said.

Since 2000, 130 human cases of West Nile virus-associated illnesses including three fatalities have been confirmed in Connecticut. Of these, seven patients acquired the infection while traveling out of state.

For more information, visit www.ct.gov/caes/mosquitotesting and www.ct.gov/mosquito.