Modified Mosquitoes

Diseases like Zika, malaria, and Chikungunya can be transmitted by mosquitoes. Modified mosquitoes are mosquitoes that have been changed to help reduce their populations and the spread of human diseases. These changes limit their ability to breed. Products that kill mosquitoes or impact their breeding are regulated by the Environmental Protection Agency (EPA). Other modifications may be regulated by the Food and Drug Administration (FDA), including products that reduce the spread of disease to or from mosquitoes.

Using modification methods may reduce some pesticide use. They may also make existing control programs more effective. EPA looks at risks for humans and the environment. Based on their analysis, harmful effects are not expected from modified mosquitoes. A few modifications are currently approved by the EPA and the FDA. As modified mosquitoes do not live for multiple generations, they may need to be released into the wild repeatedly. Three methods for modifying mosquitos are described below.

About sterilized mosquitoes:

• Male mosquitoes may be sterilized and released. Sterile males compete with wild males to breed. Wild females that breed with sterile males lay eggs that do not hatch.
• Male mosquitoes do not bite, so sterilized males do not affect humans.

About Wolbachia infected mosquitoes:

• The bacterium Wolbachia is found naturally in many insects.
• Wolbachia interferes with mosquito breeding.
• Eggs from uninfected females that breed with infected males will not hatch. Infected female mosquitoes that breed produce infected young.

About genetic modifications in mosquitoes:

• Some mosquitoes have been modified to pass on a lethal gene to their offspring. Their young will die before they can breed. OX513A is an example of this technique.
• Genetic modifications are still being developed. They are currently only used on a limited scale.

If you have questions about this, or any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email at npic@ace.orst.edu.

Additional Resources

• Genetically Modified Mosquitoes - Centers for Disease Control (CDC)
• Irradiated Mosquitoes - CDC
• New tool for combating mosquito-borne disease: Insect Parasite Gene Animation (video) - Vanderbilt University
• Final Registration Decision of the New Active Ingredient Wolbachia pipientis ZAP (wPip) strain in Aedes albopictus - US EPA
• Yes it's true: Genetically engineered mosquitoes - West Virginia University Extension
• Dengue and Chikungunya in Our Backyard: Preventing Aedes Mosquito-Borne Diseases (video) - CDC
• Florida Resident's Guide to Mosquito Control (see page 36) - University of Florida
• Bacteria of the Flies: Tracing the Spread of Disease-Controlling Wolbachia - UC Davis, College of Biological Sciences