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May 28, 2013

Scientists Developing New Weapon Against Malaria

by VOA News

Scientists are making progress in developing a new species-specific insecticide that would be lethal only to insects that carry malaria.

According to scientists at Virginia Tech and the University of Florida the insecticide would be far less toxic to beneficial insects such as bees. They say the insecticide is formulated to interfere with an enzyme found in the nervous system of mosquitoes and other organisms called acetylcholinesterase. If the effectiveness of the enzyme is disrupted, it causes an organism to convulse and die.

“A simple analogy would be that we’re trying to make a key that fits perfectly into a lock,” said entomologist Jeff Bloomquist, a professor at the University of Florida's Emerging Pathogens Institute and its Institute of Food and Agricultural Sciences. “We want to shut down the enzyme, but only in target species.”

Scientists are trying to perfect the mosquito-specific compounds and manufacture them on a large scale so that they can be applied to netting where mosquitoes might land. They say it will take at least four to five years before a compound is ready to be submitted for federal approval.

The team recently published a study in the journal Pesticide Biochemistry and Physiology comparing eight experimental compounds with commercially available insecticides that target the enzyme.

Though they were less toxic to mosquitoes than commercial products, the experimental compounds were far more selective, indicating researchers are on the right track, Bloomquist said.

“The compounds we’re using are not very toxic to honeybees, fish and mammals, but we need to refine them further, make them more toxic to mosquitoes and safer for non-target organisms,” he said.

Malaria is caused by microscopic organisms called protists, which are present in the saliva of infected female mosquitoes and transmitted when the mosquitoes bite. Initial symptoms of the disease can include fever, chills, convulsions, headaches and nausea. In severe cases, malaria can cause kidney failure, coma and death.

Worldwide, malaria infected about 219 million people in 2010 and killed about 660,000, according to the Centers for Disease Control and Prevention. About 90 percent of those infected lived in Africa.