Starting this week and continuing through the next several weeks, staff under contract with the Chicago Department of Public Health will drop larvicide in catch basins throughout the City. This annual activity is done to decrease the number of mosquitoes that are hatched and can transmit the West Nile virus. Crews are easily identifiable as they will be wearing orange vests.
What is a larvicide? A larvicide is a type of insecticide used to kill or interrupt the development of immature forms of mosquitoes, preventing them from becoming adults. The brand name of the larvicide that we use is Altosid® XR-Briquets.
Is the larvicide safe? This larvicide is registered for use by the U.S. Environmental Protection Agency and is safe for humans as well as for animals that may come in contact with it, including fish and birds.
How will I know when the larvicide is being placed in my neighborhood? Crews will be easily recognized: They will be wearing orange vests and will be walking up and down the street placing the larvicide in catch basins. They will be escorted by a City van.
How is the larvicide used? The larvicide is uniquely shaped to fit between the small openings in the catch basins. Once in the catch basin, small amounts of the active ingredient is released over time.
Which areas of the City will larvicide be placed? Larvicide is placed in areas of the City where data have shown an increased likelihood of identifying mosquitoes infected with the West Nile virus. North of 83rd Street, this includes areas west of Ashland Avenue. South of 83rd, this includes areas west of Stony Island Avenue.
Does this effort help address Zika virus? This effort is primarily focused on combating West Nile virus by decreasing the number of mosquitoes that can transmit this virus. Though Zika virus is also transmitted by mosquitoes, the risk for Chicagoans for contracting Zika virus is low, as the main species of mosquito that transmits this virus is not native to Chicago. However, we will be placing traps throughout the City to monitor for the types of mosquitoes that can transmit Zika virus. For more information regarding Zika, CDPH has created fact sheets in English and Spanish.
For more information, visit the Chicago Department of Public Health's website.