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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 larvicide treatments in sewer catch basins to kill mosquito larvae before they become adults. This proactive approach aims to reduce the population of mosquitoes that carry the West Nile virus in Chicago and its surrounding suburbs.

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 with larvicide 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.
  • The North Shore district covers a 100-square-mile area serving approximately 350,000 people.
  • Chicago currently treats 80 sewer sites out of about 210, with the number of sites fluctuating based on surveillance and funding.
  • There were 82 human cases of West Nile virus in Cook County last year.
  • In Chicago, there were 34 cases of West Nile virus and two deaths reported last year.
  • The city of Chicago sprayed pesticides seven times across more than a dozen communities during July and August of last year.
  • Mosquitoes are typically active from June through early October.
  • The use of dynamite to clear standing water for mosquito control was largely phased out by 1970.

Who's Mentioned

personJustin Harbison“Loyola University Chicago researcher and public health consultant known as the '”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.”organizationIllinois Department of Public Health“State agency monitoring virus trends.”personDr. Janna Kerins“Medical director at the Chicago Department of Public Health.”