Overview

• CDPH reports four recent infections linked to Logan Square and West Town with direct or indirect contact with rat urine or droppings.
• Four patients developed symptoms between July 16 and Aug. 28, pointing to a mid‑summer cluster under investigation.
• Clinicians are urged to test for leptospirosis, report suspected or confirmed cases to CDPH’s disease reporting line, and counsel patients on prevention.
• Health officials say most infections are mild, but about 10% progress to severe illness with potential kidney and liver failure and pulmonary hemorrhage.
• Chicago typically sees about two cases per year versus 100–150 nationwide, and residents are advised to reduce rodent exposure, avoid floodwater, and discuss dog vaccination with veterinarians.