Environment

Landmark Australian trial wipes out 80 per cent of disease-spreading mosquitoes

Landmark Australian trial wipe...
The mobile mosquito dispatch van used in the Australian trial
The mobile mosquito dispatch van used in the Australian trial
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The mobile mosquito dispatch van used in the Australian trial
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The mobile mosquito dispatch van used in the Australian trial
Male Aedes aegypti mosquito
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Male Aedes aegypti mosquito

An impressive Australian trial that released millions of sterilized male mosquitoes in Queensland has resulted in a more than 80 percent drop in the population of this disease-spreading insect. The international collaboration involved scientists from Australia's James Cook University (JCU) and the CSIRO, working with a new mosquito-rearing technology developed by Verily, an independent subsidiary of Google's parent company Alphabet.

Between November 2017 and June this year millions of male Aedes aegypti mosquitoes infected with a naturally occurring bacterium called Wolbachia were released across several trial zones across the Cassowary Coast in Northern Queensland. The infected mosquitoes still mate naturally with females but the subsequent eggs do not hatch, allowing for rapid and significant drops in the local mosquito population.

The technique has been broadly utilized for over half a century, and has been proven to be a safe and effective way to manage insect populations, but deploying it on a larger scale has always been a challenge. The big technological innovation comes from Verily's automated mass-rearing system that efficiently and robotically rears large volumes of mosquitoes and separates the sexes. It's vital that only male mosquitoes are released into neighborhoods as males are non-biting, so when they are let loose in their millions they don't have a noticeable impact on human populations.

Male Aedes aegypti mosquito
Male Aedes aegypti mosquito

Verily is currently working to pilot its technology in a number of locations around the world, most prominent is its Debug Fresno project that began in 2017 with the release of nearly 20 million male mosquitoes across two neighborhoods in Fresno County, California. The initial results of the Debug Fresno project saw a 68 percent reduction in biting, female Aedes aegypti mosquitoes compared to other neighborhoods.

This Australian trial of the technique has shown similar, if not slightly better, results in a previously untested tropical environment.

"We came to Innisfail with CSIRO and JCU 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," explains Nigel Snoad from Verily.

Another Australian project, called the World Mosquito Program, has been operating since 2011 using a similar Wolbachia infection technique. That project releases smaller volumes of both male and female Wolbachia-infected mosquitoes into the environment with the goal of slowly reducing the ability for female mosquitoes to transmit viruses. The Verily Debug project, on the other hand, is more geared towards rapidly suppressing local mosquito populations in shorter periods of time.

Source: CSIRO

12 comments
yawood
I can see how this would be beneficial in the short term but surely the numbers would build up again pretty quickly if you stopped releasing the sterilised males. It's great to reduce the numbers though.
highlandboy
So how does an 80% drop in mosquito populations effect the populations of species that rely upon mosquitoes as a food source? We may need to examine other options to minimise disease carying species, or their ability to extract blood from humans.
GaryOwens
I always hold my breath a little when I read “Australia releases something into the environment to control....................”. Their track record is not good with these things. But, hope that it works out, less biting mosies sounds like a good idea.....probably !!
Ben Samways
Awesome. Better than DEET or spraying diesel ontop of waterways! Breaks the breeding cycle.
ljaques
Reducing or eliminating the species is great, since so many people die from the virii they transmit. Now expand that program to cover all areas where aegypti roam.
CraigAllenCorson
So, what are they planning to feed the birds, bats, and dragonflies that feed on mosqutoes? After their experience with rabbits, one would think that Australians would know better than to go mucking about with nature in this haphazard way.
Lardo
Don't bats eat mosquitos? Guess they're gonna have to evolve. And pretty darn quickly, it sounds like.
Pete0097
What about the animals that are dependent on mosquitos to survive like bats? Bats need huge swarms of mosquitos to eat. The mosquitos will return and the bats will be gone. One more screw up by environmentalists.
J Scott
As much as I would like a mosquito free environment in my backyard in Florida, this can't be a good solution - those bugs - larvae & adult- are the food source for other species.... Smart people. But not smart long-term.... (fisheries....)
Wombat56
Aedes aegypti is only one of many mosquito species in the environment and it originated in Africa, so it's actually a feral pest. Also a news report about the Zika infestation said that in South America they regard the species as domesticated, as in only being found in or around human habitation. The researchers said they were unable to find Aedes aegypti in capture attempts in the jungle, so total elimination of the species would probably do no great harm.