Three types of mosquitoes tested positive for West Nile virus at a Wethersfield testing site on Goff Road, officials said.
According to the Central Connecticut Health District, the mosquitoes that tested positive for the virus are in the Culex family.
They are most active at dawn and dusk and will bite humans as well as other mammals and birds. The majority of Culex mosquitoes breed in standing water and others are found in freshwater and saltwater marshes, lakes and ponds.
The health district said mosquito testing, which began in June is expected to continue through the late fall. Test results are reported once a week by the Connecticut Agricultural Experiment Station.