by In Los Angeles, those who make war on mosquitoes are adding a weapon to their arsenal: more mosquitoes.
The Greater Los Angeles County Vector Control District launched a pilot program Thursday to release thousands of irradiated and lab-grown mosquitoes into the local environment. All of these mosquitoes are male and have been sterilized by radiation, so they are expected to find wild female counterparts and mate with dead sperm, rendering the resulting eggs unfertile. .
The target is a specific species, Aedes aegypti. The insects, which began inhabiting Los Angeles County in 2014, have evolved to help one thing – you.
“Thousands of years ago, the Aedes aegypti strain moved in close to humans and began to specialize in living near homes and biting humans,” said Daniel Hahn, professor in the Department of Entomology and Nematology at the University of Florida. “Aggressive nuisance-biters are characterized by the fact that they will bite you all day.”
Aedes Aegypti thrive in backyards and make their homes in small containers such as bottle caps and dog bowls. They can carry worrying diseases such as yellow fever, Chikungunya, Zika and dengue.
“We know our residents are suffering,” said Susanne Kluh, general manager of the Greater Los Angeles County Vector Control District, which serves 6 million people and has more than 90 full-time staff.
The district on Thursday released about 20,000 sterile male mosquitoes, dyed to appear fluorescent under a black light, as part of its final pilot program test. Male Aedes Aegypti mosquitoes do not survive, so experts say the program poses almost zero risk to humans.
Next month, the district plans to release seven to 10 sterile mosquitoes for each feral male they believe lives in the target region, the Sunland-Tujunga area of LA There could be as many as 60,000 mosquitoes in face of the week.
The strategy is an example of how people are using new technology to combat the spread of invasive mosquitoes and the diseases they can carry, as climate change, global trade and urbanization push the pests into new territory.
“They’ve evolved specifically to exploit humans as hosts, so we’re always in an arms race against them,” Hahn said.
Extended range for aggressive mosquitoes
The Aedes Aegypti mosquito is not native to the United States but has been in some regions for centuries. They even played a central role in American history: In 1793, they forced several federal officials to flee from Philadelphia, when the city was the headquarters of the US government, due to an outbreak of yellow fever.
In recent years, researchers have warned that higher temperatures due to climate change will expand the range of species. That seems to be what happened in Southern California.
The state recorded its first two cases of locally acquired dengue fever last year, which meant local mosquitoes were transmitting the virus.
“Everybody always said, well, our weather isn’t ideal, but you know, the mosquitoes adapt and our weather has changed,” Kluh said. “We get more humidity in the summer, and people create these little humid mini-climates in their backyard, with lush plants and everything.”
The region has also seen urban and suburban sprawl, which has increased the habitat of Aedes Aegypti.
Mosquitoes fight with mosquitoes
The armed mosquitoes were bred in a laboratory in Kentucky but developed from eggs obtained from the LA area. Each week, the district plans to incubate vector mosquitoes in small insect dorms and then give them a zap of radiation from a specialty machine. When released, the irradiated mosquitoes will only fly about 150 meters, Kluh said.
Hahn, who is not involved with the LA project, said that the radiation blasts up the chromosomes inside the mosquitoes’ cells, preventing reproduction and allowing the insects to fly and perform other biological functions at near-normal levels. .
Kluh said the mosquitoes will not be radioactive and will not pose a danger to the public.
The district spent about $255,000 of its $24.8 million annual budget on the program, she said: “We’ve done this on the cheap.”
However, Kluh said scaling the program across more of Los Angeles County would be a challenge. Instead, she envisions it as a targeted treatment for Aedes Aegypti hotspots and areas where cases of mosquito-borne diseases are reported.
Other regions are pursuing similar technology. In Florida, Lee County began a program to release sterile, irradiated mosquitoes in 2017. Several other California counties are also piloting the program or have purchased irradiators.
A new approach to pest control
Irradiating pests to reduce populations is nothing new. The agricultural industry has been irradiating male fruit flies for about three decades, according to Hahn.
Mosquito programs were developed 40 years ago, he said, but ultimately “were left behind because it was not cost-effective.”
Since then, however, mosquitoes have evolved to resist some common pesticides, creating a need for new solutions.
Some companies are pursuing other technologies to combat Aedes Aegypti, such as genetically modifying male mosquitoes so that they kill females, releasing male mosquitoes that carry specific bacteria or seeding a dominant gene into the population to reduce numbers.
Hahn said some of these ideas run the risk of unintended consequences but are worth researching nonetheless. Such technologies are regulated by the Environmental Protection Agency, and some are being tested in small pilot programs.
But radiation programs are not controlled, making the United States the weapon of choice today.
“We wanted to start something now,” Kluh said.
This article was originally published on NBCNews.com
