Two mosquito pools in Sarnia-Lambton have tested positive for West Nile Virus.
Lambton Public Health says the mosquitoes were collected from traps in Camlachie and Petrolia September 13.
They are the first positive mosquito pools locally this year.
Earlier this summer, a dead crow found in Sarnia's northend tested positive for the virus.
The health unit says despite the cooler overnight temperatures, mosquito season is not over and the risk of human infection will remain until frost and colder temperatures halt mosquito breeding.