Source the-scientist.com Image: Jason Rasgon (left) and Grant Hughes (right) are trying to infect mosquitoes with a life-shortening bacterium. (Image from the-scientist.com)

Scientists are trying to design the last malaria control agent the world will ever need.

Entomologist Simon Blanford attaches a spray nozzle onto the top of a jar of white-powdered fungus immersed in a concoction of mineral oils. He leans forward into a fume hood and applies an even coating of fungal spores onto cut-up strips of disposable coffee cups taped against the back wall.

The next morning, after the sopping wet strips have dried, Blanford, a senior research associate at Pennsylvania State University in State College, will return to put the cups back together. Then he’ll toss in a load of young Anopheles mosquitoes that have just eaten a malaria-ridden blood meal, cover the cups with a mesh lining, and wait. One week later, the vast majority of the mosquitoes will die, victims of the fungus that rubbed off on their bodies from the coated cups. At least, Blanford wants it to be 1 week later, which is just short enough to prevent the transmission of malaria, but long enough to potentially circumvent the evolution of insecticide resistance—indefinitely.

Malaria kills around a million people each year, and mosquitoes have developed resistance to nearly every chemical that public health officials have thrown at them. This has rendered most existing insecticides ineffective, so new practical alternatives are critically needed. With the fungus, “we’ve got a product that can break resistance to insecticide now but will also work in the long run,” says Andrew Read, a Penn State evolutionary biologist who is spearheading the project with his collaborator, ecological entomologist Matthew Thomas. Other scientists are trying to achieve the same feat—a new malaria treatment that also discourages resistance—using other biological control agents, such as a bacterium that shortens its host’s life, and through genetic engineering. “If you design the thing right from scratch you only need one product and it should last forever,” says Thomas.

But many scientists are less enthusiastic. Judging from past failures, they dismiss the Penn State researchers’ plans as lofty pipe dreams. Plus, to make this goal a reality, the scientists would have to release these “biopesticides” worldwide, raising red flags about feasibility issues and potential risks.

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Researchers at the Johns Hopkins Malaria Research Institute show off the mosquitoes they use to test for the cross-generational transmission of a bacterial infection.

Pennsylvania State University mycologist Nina Jenkins describes the process of making a fungal spore-laced spray that may help fight the spread of malaria.

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