The forearm of a public health technician covered with sterile female mosquitoes. Picture: REUTERS
The forearm of a public health technician covered with sterile female mosquitoes. Picture: REUTERS

More than 80% of a dengue fever-spreading mosquito has been wiped out in an Australian town during a landmark trial that scientists say offers hope for combating the dangerous pest globally.

Researchers from Australia’s national science body, CSIRO, bred millions of nonbiting male Aedes aegypti mosquitoes in laboratory conditions at James Cook University in a project funded by Google parent company Alphabet.

The insects were infected with the Wolbachia bacteria, which renders them sterile. They were then released into the wild at trial sites around the Queensland town of Innisfail, where over three months they mated with females that laid eggs that did not hatch, causing the population to plummet.

The Aedes aegypti mosquito is one of the world’s most dangerous pests, capable of spreading devastating diseases like dengue, Zika and chikungunya.

Millions infected 

It is responsible for infecting millions of people around the world each year and James Cook University’s Kyran Staunton says the successful trial is a major step forward. "We learnt a lot from collaborating on this tropical trial and we’re excited to see how this approach might be applied in other regions where Aedes aegypti poses a threat to life and health," he says.

The sterile insect technique has been used before but the challenge in making it work for mosquitoes is being able to rear enough of them, identify males, remove biting females and release them in large numbers to suppress a population.

To address the challenge, life sciences company Verily has developed a mosquito-rearing, sex-sorting and release technology. "We’re very pleased to see strong suppression of these dangerous biting female Aedes aegypti mosquitoes," Verily’s Nigel Snoad says.

"We came to Innisfail with CSIRO and James Cook University to see how this approach worked in a tropical environment where these mosquitoes thrive, and to learn what it was like to operate our technology with research collaborators as we work together to find new ways to tackle these dangerous mosquitoes," he says.