State warns against West Nile virus found in 4 counties in 2023

State health officials are warning about West Nile virus after virus-positive mosquitos were found in four counties, including Cook County.

No human cases have been reported this year, but the Illinois Department of Public Health is using National Mosquito Control Awareness Week, which starts Sunday, to raise awareness after 10 batches of mosquitoes tested positive for the virus in Cook, LaSalle, Morgan and St. Clair counties. The first batch of mosquitos to test positive for the virus was reported late last month in Evanston, authorities said.

“Diseases such as West Nile virus pose a serious health threat, especially to our seniors or individuals who have weakened immune systems,” public health Director Sameer Vohra said in a news release.

Vohra said the finding of positive batches of mosquitoes “underscores why it is important for Illinois residents to protect themselves this summer” by using insect repellent while outside and not keeping any standing water around where mosquitoes can breed easily.

The public health department said it has poured $2.5 million in funding to nearly 100 local health departments across the state for mosquito control efforts. Local health departments collect and test mosquitoes as well as sick or dead birds for the virus.

There were 34 positive reports of West Nile virus in humans and eight deaths attributed to the virus last year, the most since 2018, when 17 deaths were reported, according to the public health officials. The youngest person with a positive case of the virus in Illinois was 26, and the median age was 64.

Updates on cases reported and where can be found online, as well as more information about the virus itself.