Researchers in Australia have shown a bacteria can sterilize and eradicate a disease-carrying mosquito that is responsible for spreading dengue, yellow fever and Zika.

Three million male Aedes aegypti, or yellow fever mosquitoes, were released in the trial at three sites in Northern Queensland state. They were reared at James Cook University in Cairns and sterilized with a naturally-occurring bacteria called Wolbachia. 

Researchers say the bacteria appears to have changed part of the male insects’ reproductive biology, so that female mosquitoes that mate with them lay eggs that do not hatch. 

The flying insects were released over a 20-week period in 2018. Mosquito numbers subsequently fell by more than 80%. When scientists returned the following year, they found one of the trial areas had almost no mosquitoes.

Nigel Beebe is an associate professor at the University of Queensland and research scientist at the Commonwealth Scientific and Industrial Research Organization, or CSIRO. He hopes the sterilization method will eventually be used in developing countries. 

“We wanted to show in a developed country that the technology was robust, we could mass rear mosquitoes. It is not very expensive to mass rear mosquitoes and it is really the separation of the males from the females,” he said. 

The Australian team plans to use a similar technique to suppress the virus-spreading Asian Tiger mosquito that has become established in the Torres Strait in northern Australia.

“At the moment we have to use relatively sophisticated technology to do that. But we are now trying to build something that is much more robust and can be used in tropical countries and will be relatively cheap to actually be able separate the males from the females. The mass rearing of the mosquitoes is actually pretty cheap to do. So, I think, absolutely we will have application in developing countries,” saId Beebe. 

Researchers elsewhere are looking at ways to use sterile male mosquitos to curb the spread of malaria, but associate professor Beebe has said it was a “complicated” challenge. 

More than 40% of people worldwide suffer from mosquito-borne diseases. The Australian team hopes its “environmentally-friendly mosquito control” method will help tackle current and future outbreaks of dengue and other debilitating diseases. 

 
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