CDC Bottle Bioassay

Key points

  • The CDC bottle bioassay measures insecticide resistance in mosquitoes by determining if an insecticide’s active ingredient can kill target mosquito populations within a certain time frame.
  • Results of the CDC bottle bioassay can reveal when there is resistance to specific active ingredients and help inform mosquito control decisions.
Researcher adds insecticide solution to a test bottle for the CDC bottle bioassay.

About the CDC bottle bioassay

The CDC bottle bioassay is a simple, rapid, and economical test that determines if an insecticide’s active ingredient can kill target mosquito populations within a certain time frame. The test requires minimal training to characterize insecticide resistance within mosquito populations and detect changes in resistance over time. The results can help guide the choice of insecticide used for spraying.

How the CDC bottle bioassay works

Temporary program pause

The CONUS and Global Insecticide Resistance Monitoring Kit program are currently paused with plans to resume both programs in April 2026.
  • Coat a bottle with a known amount of insecticide active ingredient (diagnostic dose).
  • Place mosquitoes inside the bottle and observe for 2 hours.
  • Resistance is determined by the percentage of mosquitoes that die (mortality rate) at the pre-determined threshold time (diagnostic time).

CDC bottle bioassay diagnostic doses and times

CDC determined bottle bioassay diagnostic doses and times for numerous mosquito species against different insecticide active ingredients. The recommended testing conditions were developed separately for use in the continental United States, U.S. territories, and freely associated states and for use globally (see appropriate manual listed below for your location). This is due to differences in mosquito populations, different goals of vector surveillance, and varied operational control strategies among regions.

The current diagnostic doses and times can be used as a starting point for determining diagnostic doses and times for additional species if susceptible colonies or populations are available. Once developed, the test can be routinely used for insecticide resistance testing.

Resistance levels

Level of resistance
Mortality at diagnostic time
Susceptible (not resistant)
98–100%
Developing resistance
90–97%
Resistant
Less than 90%

Information for United States and U.S. territories

Programs in the United States, U.S. territories, and freely associated states can order free CDC bottle bioassay kits. Kits include the necessary supplies to conduct the CDC bottle bioassay to support operational decisions.

Information for global use

International institutions and programs can order a bottle bioassay kit or only insecticide active ingredients. Kits include bottles and the necessary laboratory supplies to conduct the bioassay.

Resources

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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)