Trivial Eradication Strategy: Sterile Males Render Aedes Aegypti Females Infertile
In an innovative approach to mosquito control, Los Angeles authorities are deploying sterilized male mosquitoes to curb the population of the dengue-transmitting Aedes aegypti species.
On May 2, the Greater Los Angeles County Vector Control District (GLACVCD) launched a pilot program, releasing tens of thousands of laboratory-reared male mosquitoes into the local environment. These mosquitoes have been sterilized through irradiation, rendering their sperm non-viable. The goal is for them to mate with wild females, resulting in infertile eggs and a reduced mosquito population.
Target: Aedes Aegypti, a Human-Oriented Mosquito
Aedes aegypti, the target of this initiative, emerged in Los Angeles in 2014 and has since evolved to thrive near humans. "Thousands of years ago, one population of Aedes aegypti mosquitoes moved in close with humans, started living around human dwellings and biting humans," explains Daniel Hahn, a University of Florida professor of entomology and nematology. "They're a really aggressive, vicious little biter because they'll bite you all day long."
Aedes aegypti mosquitoes breed in urban environments, laying eggs in small containers like bottle caps and dog bowls. They carry diseases such as yellow fever, chikungunya, Zika, and dengue fever, according to Susanne Kluh, general manager of GLACVCD.
Pilot Test: 20,000 Sterilized Mosquitoes to Monitor
On May 2, GLACVCD released approximately 20,000 fluorescent-dyed sterilized male mosquitoes as part of the pilot program's final test. Male mosquitoes do not bite humans, so officials assure that the program poses minimal risk to the public. Over the next month, GLACVCD plans to release 7,000 to 10,000 sterilized males for every wild male mosquito in the target area of Sunland-Tujunga, Los Angeles. The release could eventually increase to 60,000 mosquitoes per week.
Climate Change Impacts Mosquito Prevalence
This program exemplifies humanity's growing reliance on novel technologies to combat the spread of invasive mosquitoes and the diseases they carry. Climate change, global trade, and urbanization are driving these pests into new territories. Aedes aegypti is not native to the United States, but it has been present in some areas for centuries.
In recent years, researchers have warned that warmer temperatures due to climate change will expand the habitat range for mosquitoes. This is already evident in Southern California, where the first two cases of locally transmitted dengue fever were reported last year. Southern California has also experienced urban and suburban development, further expanding the habitat for Aedes aegypti.
Production Process and Safeguards
The sterilized male mosquitoes used in this program are bred in a Kentucky laboratory but are developed from eggs collected in the Los Angeles area. GLACVCD plans to incubate mosquitoes in small cages each week and then irradiate them using a specialized machine. After release, irradiated mosquitoes are only capable of flying about 150 meters, according to Kluh.
The irradiation process affects chromosomes within the mosquitoes' cells, preventing them from reproducing while allowing them to fly and perform other biological functions at near-normal levels. Kluh emphasizes that the mosquitoes are not radioactive and do not pose a health risk to the community. However, she acknowledges that scaling up the program across Los Angeles County remains a challenge.