Press Release: Mosquito Insecticide Spraying 2016

Controlling Mosquitos

The Chicago Dept. of Public Health (CDPH) will increase its level of larval and adult mosquito control. The most important steps for combating Zika and West Nile Virus (WNV) are the common sense personal precautions that every resident can take.

CDPH is highly recommending residents take the following steps to avoid Zika and West Nile Virus:

  • Use insect repellant containing DEET, Picaridin, or Oil of Lemon Eucalyptus.
  • Consider limiting outdoor activity after dark (dusk to dawn), which is when Northern House Mosquito is most active.
  • When outside between dusk and dawn, wear loose-fitting, light-colored clothing that includes long pants, long-sleeved shirts, socks and shoes.
  • Check to see that all screen on doors and windows are tight-fitting and free of holes and tears.

To limit mosquito breeding opportunities, CDPH officials recommend:

  • Draining and replacing water in birdbaths and children’s backyard wading pools every four to five days;
  • Properly disposing of old tires, jars, cans, pans, bottles, buckets and other unwanted containers that can hold standing water;
  • Making sure that rain gutters, downspouts, swimming pools and pool covers are free of standing water;
  • Keeping grass and weeds cut short to eliminate hiding places for adult mosquitoes

Efforts to Stop the Zika Virus

Though mosquitoes found to carry the Zika virus are not native to Chicago, CDPH has launched a recent campaign, #StopZika, to educate residents traveling to Zika-infested regions how to protect themselves. The campaign also reminds residents how the department is working to prevent mosquito-borne viruses that are endemic to Chicago, including West Nile virus. In addition to spraying, CDPH’s comprehensive mosquito abatement program includes dropping larvacide in catch basins, which helps limit the number of mosquitoes that can carry the virus, and regularly testing mosquitoes caught in traps throughout the city. By utilizing data the city is able to most efficiently target high-risk areas for the virus.

The material being used to control the adult mosquitoes, Zenivex™, is approved for use by the U.S. Environmental Protection Agency and has been widely applied to control mosquitoes in outdoor residential and recreational areas across the city. The spray will be applied by licensed mosquito abatement technicians from Vector Disease Control International, a leader in the mosquito control industry. Guiding the crews through the streets will be supervisors from the Chicago Department of Streets and Sanitation.

While the spray is not harmful to people or pets and is routinely sprayed in residential areas across the nation, residents of targeted neighborhoods may choose to stay indoors and close their windows while spraying is underway, as an extra precaution.

“Spraying to kill adult mosquitoes is an effective component of an integrated pest management program,” added CDPH Environmental Health Medical Director Cort Lohff, M.D. “It is our expectation that this effort will further limit the mosquito population and prevent cases of human illness in Chicago.”

As part of ongoing response efforts, CDPH will continue to collect mosquitoes from traps located throughout the city and test these mosquitoes for West Nile virus. Using results of these tests, CDPH will determine the appropriate steps to be taken in order to best protect Chicago residents. West Nile virus cannot be transmitted from person-to-person. Instead, it is transmitted strictly through mosquitoes. Most mosquitoes do not carry the virus. Additional information on the virus, including symptoms and how to protect against the virus can be found here. Additional information regarding the Zika virus can be found at