Dengue Fever: An Experiment In The Fight Against Mosquitos Yields Promising Results In Australia

Aedes aegypti. An unassuming and almost sweet name for an insect that is markedly less so. In reality, this is one of the most tragically well-known species of mosquito; the one responsible for the transmission of Dengue fever as well as the Zika and Chikungunya viruses.

Scientists recently discovered that this tiny animal’s bite devastates the human immune system. This explains the troubling ease with which the insect spreads the vast array of pathogens it can carry.

While effective measures for dealing with the threat are starting to emerge, new mosquito-borne disease outbreaks make the need for a large-scale solution an increasingly urgent one. A challenge that is, perhaps, in the process of being addressed by a promising experiment carried out in Australia with the financial backing of the American company Alphabet, which is comprised of various subsidiaries of Google.

An experiment on a town-sized scale

Directed by researchers at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) – a public scientific research agency in Australia – the trials were carried out in Innisfail, a town in the state of Queensland, in the North East of the country. The first obstacle for these scientists was to find a way of preventing the mosquito eggs from being fertilised.

They managed this by infecting Aedes aegypti with a new bacterium known as Wolbachia, a micro-organism already known for its natural capacity to interfere with the reproductive system of the common mosquito, Culex pipiens. More than three million male Aedes aegypti were infected.

The insects infected with a particular strain of Wolbachia were then gradually released between November and June 2017 and, as expected, the males sought reproductive partners among the females in the town. This caused the millions of eggs laid as a result to become infertile thanks to the bacteria carried by the males.

As a result, after a trial period of three months, researchers saw a reduction of almost 80% in the mosquito population in the area where the infected males had been released. A veritable massacre and a very encouraging victory in the large-scale fight against these notorious disease carriers. Scientists now hope to replicate this success in other affected areas.

Hope for widespread use

'We’ve learnt a lot by participating in this first tropical test and we’re excited about the prospect of seeing this approach used in other regions where Aedes aegypti constitute a major threat to public health,' says Kyran Staunton of James Cook University, one of the scientists involved in this extermination project.

This is not the first time this strategy has been put to the test; a similar experiment was carried out in Fresno, California. Meanwhile in Brazil, a British organisation has also attempted to sterilise mosquitos through genetic modification. Such promising breakthroughs could eventually lead to the eradication of the most dangerous mosquito-borne diseases. So, while the Aedes aegypti may still seem far from pleasant, it could soon be a lot less menacing.