POLISCOPE
Back to feed
NewsWBEZ ChicagoJuly 16, 2026United States

How Chicago suburbs are using sewer treatments to fight West Nile virus

Researchers and local mosquito abatement districts are using chemical treatments in sewer systems to kill mosquito larvae before they become adults. This proactive approach aims to reduce the population of mosquitoes that carry the West Nile virus, which can cause serious illness in humans.

public healthmosquito controlWest Nile virusCook Countysewer maintenance
Read the full story at WBEZ Chicago

Why It Matters

Local mosquito abatement districts treat 80,000 s in Cook County to reduce mosquito populations by over 35%, aiming to prevent the spread of the West Nile virus to the 350,000 residents in the North Shore area.

Key Facts

  • Researchers estimate that treating sewer catch basins can reduce mosquito populations by more than 35%.
  • The North Shore Mosquito Abatement District treats 80,000 catch basins across Cook County's north suburbs and parts of southern Lake County.
  • Female mosquitoes can lay up to 200 eggs at a time in sewer water.
  • Mosquitoes are typically active from June to early October.
  • There were 82 human cases of West Nile virus in Cook County last year.
  • Chicago uses larvicide in 80 sewer sites out of approximately 210, with the number of sites fluctuating based on surveillance and funding.
  • The North Shore Mosquito Abatement District covers a 100-square-mile area serving about 350,000 people.
  • The city of Chicago sprayed pesticides seven times across more than a dozen communities in July and August of last year.
  • Experts recommend using repellents containing 30% DEET, picaridin, or lemon eucalyptus oil to prevent bites.
  • Individuals over 65 or those with compromised immune systems are at the highest risk for severe West Nile virus complications.

Who's Mentioned

personJustin Harbison“Loyola University Chicago researcher and public health consultant known as the '”personDr. Janna Kerins“Medical director at the Chicago Department of Public Health.”organizationIllinois Department of Public Health“State agency tracking West Nile virus data.”organizationNorth Shore Mosquito Abatement District“Government agency responsible for mosquito control in a 100-square-mile area.”locationCook County“Region where mosquito abatement efforts are concentrated.”