The Desplaines Valley Mosquito Abatement District (DVMAD) sprayed for mosquitoes Tuesday, Sept. 8, in communities bordering Hinsdale after detecting elevated West Nile Virus levels in the local mosquito population.
Spray trucks rolled through parts of Burr Ridge, Countryside, Indian Head Park and unincorporated Lyons Township between 7:30 p.m. and midnight, weather permitting, according to a notice posted on the village of Burr Ridge's website. The district said warm temperatures had accelerated mosquito breeding and pushed transmission risk high enough to warrant adult mosquito suppression.
The targeted areas sit immediately adjacent to Hinsdale. The DVMAD website listed the spray zone as Burr Ridge within Cook County and north of I-55, Countryside north of I-55 and west of Willow Springs Road, Indian Head Park and unincorporated Lyons Township south of 55th Street and west of Willow Springs Road. Hinsdale itself was not named in the spray zone, but the district serves the surrounding area and the same mosquito population crosses municipal lines.
The spraying comes during a sharp West Nile Virus season across the region. DuPage County confirmed its first human case of the 2026 season on Sept. 1, according to Patch. The DuPage County Health Department rated the Personal Protection Index at 2, indicating a large number of infected mosquitoes.
Suburban Cook County had reported four human cases as of the week ending Aug. 22, with the risk of human infection rated high, Patch reported. In Chicago, two human cases and one death had been confirmed as of Sept. 1, according to CBS News Chicago.
Illinois reported 150 confirmed human cases in 2025, more than double the 69 in 2024. Ten people died statewide. Suburban Cook County alone accounted for 44 cases and four deaths last year.
Dr. Garth Walker, Chicago's public health commissioner, pointed to weather as a driver of mosquito activity. "2026 has seen the rainiest summer in Chicago in years, giving mosquitoes ample opportunities to breed," Walker said in a Sept. 1 statement announcing the city's cases.
DVMAD also flagged the invasive Asian Tiger Mosquito as a growing concern. The species can breed in as little water as fits in a bottle cap, the district said in an Aug. 25 update, and heavy regional rain has helped it proliferate.
The district urged residents to use EPA-registered insect repellent containing DEET, Picaridin or Oil of Lemon Eucalyptus. It also recommended wearing loose-fitting, light-colored long sleeves and pants at dusk, checking window and door screens for tears, and eliminating standing water in gutters, bird baths, buckets and pet bowls.
No follow-up spray date has been announced.
Residents can check dvmad.org or call (708) 447-1765 for updates. The DuPage County Health Department posts weekly mosquito surveillance data at dupagehealth.org.
