Updated

Updated · WTTW News · Sep 1

Illinois Reports 1st 2026 West Nile Death in Chicago as City Confirms 2 Human Cases

Updated

Updated · WTTW News · Sep 1

Illinois Reports 1st 2026 West Nile Death in Chicago as City Confirms 2 Human Cases

Q: Since most infected people never show symptoms, could you have already contracted this year's West Nile virus without even realizing it?

Yes. Because about 80% of West Nile infections cause no symptoms, it is entirely possible to have been infected this season and never know it. That is one reason official case counts understate how much virus is circulating. Most diagnosed cases are the smaller share of people who develop symptoms serious enough to seek care and get tested. In Chicago and across Illinois, the confirmed human cases and mosquito positives show the virus is active, but they do not capture every infection. If symptoms do occur, they usually begin 2 to 14 days after an infected mosquito bite, most often within 2 to 6 days. Mild illness can look like many other summer viruses: fever, headache, body aches, joint pain, nausea, diarrhea, or rash. Fewer than 1% of infected people develop severe neurologic disease such as meningitis, encephalitis, weakness, or paralysis. There is no reason for most healthy people to get tested simply because they were bitten by mosquitoes and feel fine. Testing is generally used when a doctor suspects West Nile based on symptoms and mosquito exposure. Blood tests look for antibodies, but timing matters; testing too early can miss an infection. Anyone with high fever, severe headache, neck stiffness, confusion, tremors, muscle weakness, or paralysis should seek medical care promptly. Older adults, people with chronic conditions, and those with weakened immune systems face the highest risk of severe illness.

3 articles · Updated · WTTW News · Sep 1

Chicago health officials reported Illinois' first West Nile virus death of 2026 and confirmed the city's first two human cases, though they released no details about the person who died.
The cases come after the state's first human infection was identified last week in Piatt County and suburban Cook County reported four cases, signaling wider seasonal spread.
Chicago officials tied the risk to one of the city's rainiest summers in years, saying wetter conditions gave mosquitoes more places to breed.
Illinois recorded 10 West Nile-related deaths and 150 human cases in 2025; with no specific treatment, health agencies are urging residents to prevent mosquito bites and remove standing water.