Researchers at the University of Melbourne, Australia, have discovered that an anti-malarial drug called Atovaquone, which was thought to be ineffective, has the ability to combat the malaria parasite.

Introduced in 2000, Atovaquone is safe for pregnant women and children. However, it was phased out of use because the malaria parasite developed resistance to it.

According to the latest study, although some malaria parasites had developed a genetic mutation that protected them against the drug in early life, the mutation eventually killed the parasites by stopping production of an essential type of energy as they grew.

As published in the journal Science, scientists tested three atovaquone-resistant strains of the rodent malaria parasite Plasmodium berghei, each with different mutations in their mitochondrial DNA-encoded cytB gene (14, 15), for transmissibility from mouse to mosquito and back to mouse.

In order to become resistant to the drug, the parasite changed the way it releases energy from food, BBC reported.

This alteration helped the parasite survive the chemical attack in the mouse's bloodstream where there is a supply of sugar.

University of Melbourne School of Biosciences Professor Geoff McFadden said: "We now understand the particular genetic mutation that gave rise to drug resistance in some malaria parasite populations and how it eventually kills them in the mosquito, providing new targets for the development of drugs."

"So the development of drug resistance may not be a major problem if the resistance cannot spread, meaning the drug atovaquone could be more widely used in malaria control."