You may have read the news that the first genetically altered mosquito release in the U.S. has started in Florida. This news may have you asking questions and using internet search engines to find answers. We found some of the commonly asked questions about genetically altered mosquitoes and asked one of our entomologists to answer those questions. Read on to learn more.

aedes aegypti mosquito

Dr. Angela Tucker, BCE

Why are they releasing genetically modified mosquitoes?

The Environmental Protection Agency (EPA) has granted Oxitec LTD an experimental use permit (EUP) for targeted release of the mosquitoes in some counties in Florida. The goal of the release is to collect data and evaluate the efficacy of the genetically modified mosquitoes. The data collected will provide information that may demonstrate a reduction in the desired species population.

Will the genetically modified mosquitoes target all species of mosquitoes in Florida?

No, the EUP allows for the release of OX5034 Aedes aegypti males. This means that only A. aegypti mosquitoes will be targeted. A. aegypti are an invasive mosquito, and they can carry pathogens for a variety of diseases, including chikungunya, Zika and dengue.

How do genetically modified mosquitoes affect the mosquito population?

The release in Florida will be in the Florida Keys, where it is estimated that 4% of the total mosquito population is A. aegypti. That sounds like a very small number, but remember that the goal is to evaluate the ability to reduce the population of A. aegypti, which is an invasive species and can carry diseases that can impact humans and pets.

What you may now be thinking is how is that going to work if only genetically modified males are released? Oxitec describes this process in detail, but here are the key points:

  1. The OX5035 A. aegypti males carry a gene that prevents female offspring from surviving.
  2. The males are released, and they may find and breed with wild A. aegypti females.
  3. The resulting offspring will be males that carry a copy of the gene. (Remember: The females do not survive to adulthood.) Basic genetics dictate that the male offspring are carrying the gene because half of their genetic makeup came from the wild female and the other half from the genetically modified male.
  4. The offspring — male gene carriers — may find and breed with wild A. aegypti females, and approximately half of their offspring will receive the gene. Females that carry the gene will not survive, and about half of the males will receive the gene.
  5. In theory, the population is decreased due to the reduction of females. But not all wild females will breed with a genetically modified male or a male that carries the gene that prevents female offspring survival. This process can take time to achieve population reduction and repeated genetically modified male releases.

Are genetically modified mosquitoes safe?

In order to receive an EUP, a human health and environmental risk assessment must be submitted and reviewed by the EPA. You can read the full OX5035 A. aegypti assessment online. The EPA determined that there will be no unreasonable adverse effects for humans, the environment or non-target organisms. Because this method targets a specific species and has a lethal gene effect, it is theorized that the gene itself will eventually disappear from the population without repeated release of the genetically modified males. The EUP was approved in order to test and evaluate the theories.

What kind of impact will the genetically modified mosquitoes have on mosquito bites?

The goal is to reduce the number of female A. aegypti, which are the biters. Because they are a small portion of the mosquito species complex — or population — in the Florida Keys, some individuals in the area may not see a change in bites.

Will genetically modified mosquitoes replace the need for professional mosquito control and other methods of repelling and controlling mosquitoes?

No, this project is focusing on one mosquito species in an area where they have about 46 species. The Florida Keys Mosquito Control District recommends that you contact them if you are having mosquito concerns or need additional information about the program. Follow the CDC guidelines on selecting and using mosquito repellents, wear long-sleeve shirts and long pants, and minimize your outdoor activity at dusk or during the day in areas where you have day-biting mosquitoes, such as A. aegypti. All these activities will help reduce the risk for bites.

Emptying containers that hold water — even those as small as a soda bottle cap — can also reduce the areas where female mosquitoes can lay their eggs. A good rule of thumb is: If the container can hold water for 5 days, it should be emptied every 5–7 days.

Contact a professional pest control company such as Terminix® to schedule regular mosquito treatments for resting areas in yards to reduce the number of mosquitoes on your property.

Will the genetically modified mosquitoes expand to target other species of mosquitoes?

Because the gene in the genetically modified males is specific to A. aegypti, it is not going to target other species. However, Oxitech is expanding this technology for other species, such as Anopheles albimanus, a mosquito that is found in Meso-America and can carry malaria, and the Diamond back moth, Plutella xylostella, the larvae of which are a major pest of crops such as broccoli, cauliflower and others.