CHICAGO — City health officials have confirmed that mosquitoes testing positive for West Nile virus have been detected in several parts of Chicago, raising concerns as summer temperatures rise and mosquito activity increases.
No human cases have been reported yet in Chicago or anywhere else in Illinois, but the Chicago Department of Public Health (CDPH) is urging residents to take preventive action now to minimize risk.
Other Areas Affected Beyond Chicago
In addition to the Chicago samples, West Nile-positive mosquitoes have also been identified in Glenview, as well as McHenry and DuPage counties, according to regional reports.
These confirmations mark the first known detection of the virus in the city for the 2025 season. Typically, human infections peak between July and September, depending on weather and mosquito population levels.
Symptoms and Risks of West Nile Virus
The West Nile virus is primarily spread to humans through the bite of an infected mosquito. While most people infected show no symptoms, others can develop serious illness.
According to the CDPH, common symptoms may include:
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Headache
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Body aches and joint pain
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Vomiting or diarrhea
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Skin rash
In rare cases, particularly among older adults or those with weakened immune systems, the virus can lead to neurological complications, including encephalitis or meningitis.
City Recommends Prevention Measures
To reduce the risk of exposure, CDPH is encouraging residents to take the following precautions:
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Inspect window and door screens for holes and repair them if needed
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Use air conditioning when possible to reduce indoor exposure
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Apply EPA-registered insect repellent as directed
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Wear long-sleeved shirts and pants when outdoors, especially between dusk and dawn, when mosquitoes are most active
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Empty standing water containers weekly — including flowerpots, birdbaths, buckets, and gutters
“It’s critical for people to protect themselves by reducing mosquito breeding and avoiding bites,” CDPH officials emphasized in their statement to WGN-TV.
Looking Ahead As Summer Progresses
The city will continue monitoring mosquito pools throughout the summer as part of its vector control program, and more detections are expected in the coming weeks.
Although human infections have not yet occurred this year, residents are reminded that early-season mosquito detection often precedes surges in human illness later in the summer.
Share your tips or concerns with us at ChicagoSuburbanFamily.com and help others stay safe this season.
