Chicago has recorded its first death from West Nile virus this year, according to the Chicago Department of Public Health (CDPH). The announcement comes as several other cases of the mosquito-borne illness have been reported across Illinois. Officials cited the city's unusually wet summer as a primary factor contributing to increased mosquito breeding.
"2026 has seen the rainiest summer in Chicago in years, giving mosquitoes ample opportunities to breed," CDPH Commissioner Garth Walker stated. "The best way to protect yourself from West Nile virus is to avoid mosquito bites and take measures to stop them from breeding around your home."
In response to the rising cases, the CDPH has conducted insecticide spraying in multiple community areas, including Beverly, Burnside, Chatham, East Garfield Park, the Lower West Side, Morgan Park, the Near West Side, North Lawndale, O'Hare, Pullman, Roseland, South Deering, Washington Heights, West Lawn, and West Pullman.
West Nile virus is typically transmitted to humans through the bite of an infected mosquito, which contracts the virus from birds. While most human cases are asymptomatic or result in mild, flu-like symptoms such as fever, headaches, body aches, and rashes, a small percentage can develop into severe neuroinvasive disease. This can manifest as meningitis, encephalitis (brain inflammation), paralysis, or even death.
Individuals over the age of 50 and those with weakened immune systems are considered to be at higher risk for severe illness. Dr. Tyler Evans, an infectious diseases specialist at the University of Southern California Keck School of Medicine, noted that about 20% to 25% of symptomatic individuals experience flu-like symptoms that can be difficult to distinguish from influenza. He emphasized that severe headaches, stiff neck, disorientation, vision loss, or confusion, particularly in those over 65 or with immunocompromising conditions, warrant immediate emergency medical attention.
There are no specific vaccines or treatments for West Nile virus, but supportive care can manage symptoms. For mild cases in individuals not at high risk, supportive treatment at home is often sufficient. However, for those in higher-risk groups experiencing severe symptoms, seeking emergency care by calling 911 is crucial.
Preventive measures focus on avoiding mosquito bites and reducing breeding grounds. Health officials recommend using insect repellents containing DEET, wearing loose, long-sleeved clothing, and ensuring window screens are intact. Eliminating standing water around homes, such as in buckets or old tires, is also a key step in preventing mosquitoes from multiplying. Officials also advise avoiding outdoor activities during dawn and dusk when mosquitoes are most active.
Nationwide, as of September 1, preliminary CDC data indicated 407 reported human cases of West Nile virus this year, including 285 severe neuroinvasive cases and 23 deaths. The majority of West Nile cases typically occur in August and September.