Four mosquitoes in Wilton have tested positive this summer for Jamestown Canyon virus, according to data from the Connecticut Agricultural Experiment Station. Statewide so far this summer, 20 mosquitoes have tested positive for the virus and one, caught at Cove Island Park in Stamford, tested positive for West Nile virus.

West Nile and Jamestown Canyon virus are two of the illnesses the state tests for each summer. The others are eastern equine encephalitis and the Zika virus, which have not been detected in mosquitoes.

The four positive mosquitoes all were caught at the trap on Spectacle Road, where 1,416 mosquitoes were taken and tested.

Symptoms of Jamestown Canyon virus may include fever, headache, and flu-like illness.

Severe cases involving the central nervous system may include meningitis or encephalitis. Meningitis is inflammation of the membranes surrounding the brain. Encephalitis is inflammation of the brain itself.

Treatment involves supportive care until the illness resolves. Those most at risk are infants, the elderly and people with damaged immune systems.