Using a fungus as a mosquito repellent is an organic way to get rid of malaria in many areas of the world. Scientists are combining this organism with a spider toxin to eliminate malaria-carrying mosquitoes. Once widespread, this method can help end malaria.
Scientists performed trials in Burkina Faso. The results showed a 99% decrease in mosquito populations in just 45 days. Experts say that the aim is not to make the mosquito species extinct. The only goal is to end malaria. This dangerous disease spreads through the bites of female mosquitoes. The malaria pathogen enters the host’s bloodstream as these mosquitoes drink from a human. It ends up killing at least 400,000 people annually. There are about 219 million cases of malaria every year.
The Fungus and the Spider
The IRSS research institute located in Burkina Faso has researchers working with the experts at the University of Maryland. They identified the essential fungus for the trials—Metarhizium pingshaense. This fungus infects the Anopheles mosquitoes naturally. Scientists need to enhance the fungus. Genetically engineering it was easy, according to the scientists from the University of Maryland.
To do this, they turned to a funnel-web spider species in Australia. They added the genetic directions of the spider’s toxin to the fungal genetic code. The fungus ended up manufacturing the toxin once it enters the mosquito.
The scientists used the fungus to deliver the toxin instead of using the fangs of the spider. The results of the trials showed that the genetically-enhanced fungus was able to kill faster. It even needed fewer fungal spores than they expected. Testing the fungus in a real-world setting was the next step.
The Real World Setting
The trial involved creating a 6,500-square-foot village in Burkin Faso. It was almost like a real village, complete with water and available food for mosquitoes. The village was covered with double-layered mosquito netting. This prevented the mosquitoes from escaping.
Wiping sesame oil on the black cotton sheets allows the fungus to enter the mosquitoes. The insects had to land on the sheets to become infected with the fungus. There were 1,500 mosquitoes in the trial. The mosquitosphere contained the mosquitoes for 45 days. The mosquitoes that did not have access to the fungus multiplied.
The ones that were infected with the fungus decreased in number. There were only 13 of them left after 45 days. The fungus was specific to the Anopheles mosquitoes. It left the other insects alone.
The selective fungi know where they actually are. This is possible by detecting the shapes of the mosquito’s body and the chemical signals given off by the host mosquitoes. Metarhizium pingshaense likes mosquitoes. Once the fungus knows that it is on the target mosquito, it goes through the mosquito’s cuticle covering and enters the insect’s body.
The fungi are also effective in mosquitoes that are already immune to insecticides. The gene drive controls the mosquitoes. Whether in a lab or real-world settings, these insects do what they are supposed to do. This enables the fungi to work as planned. The chosen fungi in this malaria-fighting effort is selective. It naturally likes to live in mosquitoes. This makes it easier for scientists to use them as vehicles for the spider toxin. The malaria-carrying mosquitoes die off in a span of 45 days. This is a natural, efficient, and sustainable way to remove malaria from the face of the Earth.