Mosquitoes are famously attributed their ability to spread germs. Eager to bite both humans and animals, this action can start a deadly cascade of disease transmission. However, with the aid of a self-limiting gene, mosquito species in the United States are undergoing the process of being genetically modified to prevent potential disease outbreaks in areas with vulnerable human populations.
According to the Centers for Disease Control and Prevention (CDC), mosquitoes can be divided into one of two categories: vectors or nuisances. A vector, described as “an animal, insect, or tick that spreads pathogens,” can make a person or animal sick from a bite. In comparison, a nuisance mosquito may bite, but will not spread pathogens during that time.
With such classification, invasive mosquito species such as Aedes aegypti Further studies are being conducted by biologists to understand where and how they are spreading viral diseases. States such as California and Florida are becoming primary hotspots for AEs. aegypti colonization because it is a species that thrives in warm climates. At the same time, the climate change crisis offers no consolation as temperatures continue to rise.
In efforts to prevent future outbreaks of viral diseases that this invasive species may spread, the United States Environmental Protection Agency passed an experimental use permit for the release of more than 2.4 million genetically modified Ae. aegypti Mosquitoes in California and Florida. From March 7 this year, both the states will release the first batch of around 1.2 million mosquitoes by April 30, 2023. For another full year, the release of the second batch with the same amount of insects will begin on April 30, 2023. This second round is expected to run until April 30, 2024.
As the driving force behind the project, Oxitech, a biotechnology company, described it as “a leading developer of biological solutions to control pests that spread disease, destroy crops and damage livestock” The aim is to reduce AE. aegypti populations in the wild with exposure to genetically modified mosquitoes mass-produced by their laboratories.
The process of producing genetically modified insects is driven by the insertion of a self-limiting gene into male mosquitoes. This modified gene prevents the offspring of female mosquitoes from surviving long enough to become adults.
Genetically modified female mosquitoes first lay eggs in the laboratory, where these eggs contain both a self-limiting gene and a fluorescent marker gene that allows researchers to identify them in the wild. Once ready, the eggs are released into a special environment where they are expected to hatch and develop normally into adulthood. As adults, male mosquitoes continue their lives by mating with wild Ae. aegypti females, who pass self-limiting genes to their offspring. The female offspring that will be born will die before they are able to become adults, which should suppress the Ae. aegypti population.
At UCI, professors of microbiology and molecular genetics such as Anthony James are involved with experiments that aim to prevent future disease outbreaks. As a researcher who studies Ae. aegypti species, James’ own research focuses on developing “novel, genetics-based control methods” that would allow the transmission of human pathogens by host mosquitoes to be blocked.
The use of genetically modified AEs through such biological control as suggested by James. aegypti mosquitoes can produce positive results in the scientific community.
Because the modified mosquitoes are intended to target the invasive Ae. aegypti species, will not harm native species in the wild. The organic food chain in the wild will be maintained as animals such as birds continue to use native mosquito species as a source of food.
The risks associated with genetically modified mosquitoes are low because the modified self-limiting genes in female offspring will not be passed on to humans. Although female mosquitoes are the sex of the biting insect, they do not have the ability to transmit this gene, which many may be concerned about.
To read more about the Oxitec project and get updates on the work being done, visit the biotechnology company’s official website.
Corintia Espinoza is a STEM staff writer. he can be reached here [email protected],