The Chicago Department of Public Health announced that crews will apply insecticide on Monday night, August 17, 2026, across the Beverly, Morgan Park and Washington Heights neighborhoods. The treatment is intended to reduce mosquito populations following the detection of West Nile virus in the area.
The operation comes after a planned mosquito‑control spray was postponed the previous week because of severe storms. Weather conditions had prevented the safe and effective application of the insecticide, prompting city officials to delay the effort until conditions improved.
Health officials confirmed a West Nile virus case that triggered the expedited response. By targeting the three neighborhoods where the virus was identified, the department aims to limit further transmission and protect residents from additional exposure.
The insecticide application will take place during the evening hours on Monday, a time chosen to maximize coverage while minimizing disruption to daily activities. Residents in the affected districts have been advised to stay indoors during the spray and to keep windows and doors closed until the treatment is completed. The department emphasized that the chemicals used are approved for public‑health mosquito control and are applied according to state and federal safety guidelines.