Chicago confirms its first West Nile virus death of 2026 as national case count reaches 407 across 40 states
Chicago confirmed its first West Nile virus death of 2026 this week. CDC data cited by ABC News put the national count at 407 cases across 40 states as of September 1, including 285 neuroinvasive infections. No vaccine exists. CDC says mild cases are widely underreported.
Chicago health officials confirmed the city's first West Nile virus death of 2026 this week, alongside two human cases in the city, and pointed to the rainiest Chicago summer in years as a driver of expanded mosquito breeding. The Cook County health department separately reported its first four suburban cases in late August, and Illinois has now detected the virus in 50 counties this year. Nationally, CDC ArboNET data cited by ABC News put the case count at 407 across 40 states as of September 1, including 285 neuroinvasive infections and 23 deaths. That pace already runs well ahead of 2003, the worst West Nile season on record in the US, at a comparable point in the year. CDC cautions its figures are preliminary and likely undercount the real infection total, since about four in five people infected never develop symptoms and are never tested. There is still no licensed human vaccine or antiviral treatment for West Nile virus. People over 60 and those who are immunocompromised or living with chronic conditions face the highest risk of the severe neuroinvasive form, which can cause lasting weakness after recovery. Mosquito bite prevention, repellent, long sleeves at dusk and dawn, and removing standing water around homes, remains the only available protection during the remaining weeks of peak transmission season.