Male mosquitoes will be genetically modified to poison females with sperm in Australian research | Health

Toxic male mosquitoes will poison females with their sperm in a new population control method developed by Australian researchers.

The method involves genetically modifying males to produce spider and sea anemone venom proteins, which they inject into females during mating, thereby reducing their lifespan.

Macquarie University researchers tested the ‘toxic male technique’ on a species of mosquito that spreads dengue, Zika and other viruses, after a study using fruit flies was published in the journal peer-reviewed by Nature Communications.

Lead author Sam Beach said the species-specific approach could be used to quickly suppress outbreaks of mosquito-borne diseases, such as dengue fever – which causes 390 million cases worldwide each year – without having to spray huge quantities of insecticides which can decimate local populations. insects.

“Ideally, what we’re trying to achieve is: A male mosquito mates with a female, and then she immediately dies,” he said.

Injecting a new gene into freshly laid mosquito eggs using tiny glass needles was “a very tedious process”, he added.

Only female mosquitoes feed on blood. They typically mate within 24 to 48 hours of emergence, but can live and continue biting for several weeks, allowing continued spread of the disease.

The toxic technique for men could reduce blood supply rates by 40 to 60 percent, the study found.

While other genetic biocontrol approaches have used males to reduce the viability, blood supply or disease-transmitting ability of mosquito offspring, Beach said the new method directly targets females.

“With this approach, we can immediately reduce the population size of female mosquitoes and hopefully achieve a very rapid reduction in the spread of these vector-borne diseases. »

Dr Tom Schmidt, an evolutionary biologist from the University of Melbourne, who was not involved in the study, said pesticide resistance was a global problem, prompting scientists to develop other approaches to pest control.

“Mosquitoes become resistant to insecticides very quickly and can spread resistance. They can scale it, and they can also spread it by getting on ships and planes and broadcasting it all over the world.

An Australian approach that infected mosquitoes with Wolbachia bacteria significantly reduced dengue transmission in north Queensland, he said. Genetic approaches could also work, he said, emphasizing that mosquito control was not a one-size-fits-all approach.

Climate change is also causing mosquito species to appear in places they have never been before.

Professor Philip Weinstein, an infectious diseases researcher at the University of Adelaide who was not involved in the study, said there were thousands of species of mosquitoes, but only a few carried diseases.

Weinstein said an ideal solution would be to control the insects without eradicating them, given that mosquitoes are pollinators and an important food source for fish and bats.

“Ecosystem health – things that happen in the environment, including mosquitoes, but also water quality, air quality, climate change, loss of biodiversity – all have an impact, direct or indirect, on human health,” he said.