Spider-toxin producing fungus: malaria cure?


A recent study in Burkina Faso suggests that a genetically enhanced fungus can wipe out up to 99% of mosquitoes within 45 days.

With 219 million cases of malaria globally every year, resulting in more than 400,000 deaths, there is a high demand for a solution to the disease. Vaccine trials are the most popular option, with a major vaccine trial beginning in April 2019 in Africa, but could targeting the mosquito vector also be a solution?

The main malaria controls implemented consist of malaria nets impregnated with pyrethroid, an insecticide, or spraying of insecticides around buildings. However, recently, some malaria carrying mosquitoes have developed insecticide-resistance, which calls for new methods to be rapidly developed for their eradication.

A genetically enhanced fungus can wipe out up to 99% of mosquitoes

As well as transmitting malaria, Anopheles mosquitoes are prone to infections themselves, and this is what researchers at the University of Maryland in the US and in Burkina Faso decided to investigate. Metarhizium pingshaense is a fungus that naturally infects Anopheles mosquitoes, and was genetically enhanced to produce a spider toxin to kill the mosquitoes.

From a species of funnel-spider found in Australia, the toxin proves a more effective killer in the genetically modified (GM) fungus, than the fungus alone. Tests found that the GM fungus needed fewer fungal spores to kill and could kill more rapidly than the fungus. Not only that, but it reduces the amount of blood-feeding by the mosquitoes infected, which reduces transmission of malaria.

To test the GM fungus in near-field conditions, a 6,500-sq-ft fake village, known as a MosquitoSphere, was set up in Burkina Faso. It had all the mod-cons you would expect from a fake village, including plants, huts, breeding sites, food and water sources for the mosquitoes.

There are around 219 million cases of malaria worldwide every year

After leaving them to their own devices without introducing the fungus, numbers of insecticide-resistant mosquitoes soared. But with the introduction of the modified fungus, around 75% of the insecticide-resistant mosquitoes became infected with the GM fungus, leading to the population shrinking by 99% in 45 days.

The success of this trial could mean promising things for malaria reduction in the worst hit endemic areas, including regions of Africa, Asia and the Americas. But could this mean the end for Anopheles mosquitoes? At the risk of tampering with nature too much, the fungus treatment would only be used in specific locations to avoid wiping out a whole species of mosquito which would impact the ecosystem at large.

But what about the rest of the animals? The fungus only infects the mosquitoes, so won’t damage other insects or animals in the vicinity, limiting collateral damage of the method.

Next on the list for this malaria treatment is fully elucidating the scope of the GM fungus, but with the promising results researchers are excited for its prospects out in the real world.

Image by Frank Starmer via Flickr and Creative Commons.

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