A 73 year old Bloomington man tested positive for West Nile virus earlier this month.
He was hospitalized, but has since recovered.
The McLean county health department recommends using mosquito repellent while outside, especially at dawn and dusk.
It also encourages people to check door and window screens for holes, which are an easy way for the insects to get inside.
This is the county's first human case of West Nile since 2007.