Australian funnel web venom could help fight malaria

By Holly Cormack 3 June 2019
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Genetically modified fungus decimates malaria mosquito populations.

A RECENT STUDY shows that a fungus, which has been genetically modified to produce spider venom, can rapidly kill large populations of malaria-spreading mosquitoes. Trials carried out in West Africa saw Anopheles mosquito populations drop by 99 per cent in a simulated village.

Malaria is spread by the female Anopheles mosquito, which during a blood meal, injects the parasite into its human host.

More than 400, 000 people die of malaria every year. About two thirds of these fatalities are young children (under the age of five) in sub-Saharan Africa.

The researchers from the University of Maryland and the IRSS research institute in Burkina Faso used Metahizium Pingshaense – a fungal species that naturally targets the Anopheles mosquito – and enhanced its toxicity using the venom of the Australian Blue Mountains funnel-web spider.

In the field trial, scientists witnessed the mosquito population collapse to unsustainable levels within two generations. The fungus was also proven to be uniquely deadly to mosquitos and leaves other insects unharmed.

“These fungi are very selective. They know where they are from chemical signals and the shapes of features on an insect’s body,” says Raymond St. Leger, a Professor of Entomology at UMD and co-author of the study.

“The strain we are working with likes mosquitoes. When this fungus detects that it is on a mosquito, it penetrates the mosquito’s cuticle and enters the insect. It won’t go to that trouble for other insects, so it’s quite safe for beneficial species such as honeybees.”

Next, the scientists hope to test their transgenic fungus in a local village or community; however there are many social and regulatory obstacles that need to be overcome first.

“We demonstrated that the efficacy of the transgenic fungi is so much better than the wild type that it justifies continued development,” said St. Leger.

The rising threat of insecticide resistance among Anopheles mosquitos has made research into new anti-malarial technologies critically important. Insecticide-treated bed nets, which are the primary tool for preventing malaria, have lost some of their power in recent years.

According to the World Health Organisation, ‘the 10 highest burden countries in Africa reported increases in cases of malaria in 2017 compared with 2016.’

This study is particularly promising because it is easy for local communities to employ and can be used in conjunction with insecticides to kill a larger portion of the mosquito population.

“Simply applying the transgenic fungus to a sheet that we hung on a wall in our study area caused the mosquito populations to crash within 45 days,” says Brian Lovett, a graduate student in UMD’s Department of Entomology.

“And it is as effective at killing insecticide-resistant mosquitoes as non-resistant ones.”