In Los Angeles, the Greater Los Angeles County Vector Control District has launched a pilot program to release tens of thousands of sterilized, irradiated, lab-raised mosquitoes into the local environment. The target species is the Aedes aegypti mosquito, which has become a nuisance in the area since 2014. These mosquitoes are aggressive biters that can carry diseases like yellow fever, Chikungunya, Zika, and dengue. The goal of the program is to release sterile male mosquitoes that will mate with wild females and render the resulting eggs worthless, thus reducing the population of this species.
Aedes aegypti mosquitoes thrive in backyards and small containers like bottle caps and dog bowls, and have evolved to specialize in living near people and biting them. The Greater Los Angeles County Vector Control District released about 20,000 sterile male mosquitoes in the final pilot program test, dyed to appear fluorescent under a black light. Next month, they plan to release up to 60,000 sterile mosquitoes per week in the Sunland-Tujunga area of L.A. as part of the full-scale program. The strategy is part of ongoing efforts to combat the spread of invasive mosquitoes and the diseases they carry due to climate change, global trade, and urbanization.
Aedes aegypti mosquitoes are not native to the United States but have been present in some regions for centuries. Researchers have warned that climate change is expanding the range of these mosquitoes, leading to cases of locally acquired dengue fever in Southern California. Urban and suburban sprawl has also provided more habitat for these mosquitoes. The weaponized mosquitoes used in the program were bred in a Kentucky laboratory but developed from eggs sourced from the L.A. area. They are sterile due to radiation, which prevents reproduction while allowing them to perform other biological functions normally.
While the concept of irradiating pests to control populations is not new, it is a relatively new approach for mosquitoes. Other regions, such as Lee County in Florida, are also implementing similar programs with irradiated mosquitoes. The agricultural industry has been irradiating male fruit flies for about three decades, and new technologies are being explored to combat Aedes aegypti mosquitoes, such as genetically modifying male mosquitoes and releasing those carrying bacteria. These approaches are regulated by the Environmental Protection Agency, and some are being tested in pilot programs.
The district has spent approximately $255,000 of their annual budget on the program, with plans to target Aedes aegypti hotspots and areas with reported cases of mosquito-borne diseases. The goal is not to scale the program county-wide due to cost constraints but to use it as a targeted treatment strategy. While some of these new technologies carry risks of unintended consequences, they are being researched and tested to find effective solutions to mosquito control. The Greater Los Angeles County Vector Control District has taken action now with the irradiated mosquito program to combat the spread of invasive mosquitoes and the diseases they can transmit.
