The Asian Tiger mosquito -- which is capable of carrying the Zika virus -- has been detected in Windsor-Essex.
The Health Unit says two were found in mosquito traps.
Both tested negative for Zika and the West Nile Virus.
The Asian Tiger is not the species that is responsible for the majority of human cases of Zika virus infection in the Caribbean, South America and Florida.
Last year, 17 of mosquitoes were found in Windsor-Essex but also tested negative for Zika and West Nile.