Can Malaria Be Controlled Without Chemicals?

Close to half of the world’s population resides in areas vulnerable to malaria, as such approximately 450,000 people die annually of malaria, most of which are children and pregnant women. Progress in the battle against malaria has been threatened due to Anopheles developing resistance to toxic chemical insecticides being used to control them. 

Roughly three decades ago a strain of bacteria was identified that kills Anopheles, but since its method of attack was not understood it could not be replicated or used as an alternative to the toxic chemicals until now. 

An international team of scientists led by Sarjeet Gill from University of California Riverside have successfully identified a neurotoxin produced by the bacteria and also determined how it kill Anopheles. It took the team a decade to reach this breakthrough which is attributed to modern gene sequencing techniques. 

The team hit the bacteria with radiation which created mutant bacterial strains that could not produce the toxin; by comparing the toxic and nontoxic strains the team was able to find proteins in the bacteria which are the key to toxin production that kills Anopheles. 

"Identifying the mechanisms by which the bacteria targets Anopheles has not been easy," Gill said. "We were excited not only to find the neurotoxin, called PMP1, but also several proteins that likely protect PMP1 as it's being absorbed in the mosquito's gut. It was surprising for us that PMP1 is not toxic to mice even by injection."

PMP1 is 30% chemically similar to tetanus or botulinum, but because this neurotoxin does not affect fish, vertebrates, humans, or other insects the team believes the bacteria that produces PMP1 likely co-evolved along with Anopheles mosquitoes. 

A patent has been applied for this discovery, and the team is looking to find partners to help them develop this bacteria based Anopheles killer to fight malaria. Findings also open new paths of research for other more environmentally friendly insecticides. 

“There is a high likelihood that if PMP1 evolved to kill the Anopheles mosquito, there are other toxins that can kill other disease-spreading pests," Gill said. "This could just be the start of a new way to prevent hundreds of thousands from getting sick and dying every year."