Overview
- The Chicago Department of Public Health confirmed on Friday that two mosquito pools tested positive for West Nile virus while no human cases have been reported in the city so far.
- City crews are conducting weekly mosquito collection and testing, treating more than 80,000 storm‑drain catch basins with larvicide and targeting adult mosquitoes with spraying as part of an expanded control effort.
- Most people infected do not get sick, about one in five develop fever or flu‑like symptoms, and roughly one in 150 develop serious neurologic illness with risk highest for people over 55 or those with weakened immune systems.
- Health officials advise concrete steps to cut bite risk: use EPA‑registered repellents such as DEET or picaridin, wear long sleeves at dawn and dusk, repair screens, empty standing water weekly and use air conditioning when possible.
- The city’s finding follows West Nile–positive mosquito detections elsewhere in Illinois in mid‑May and raises the risk through the June–October peak season so residents should watch public updates and the CDPH surveillance dashboard for new test results.