Antimalarial resistance to drug unable to spread by mosquitoes

In a study they might be helpful for malaria control, scientists said Thursday that resistance to the antimalarial drug atovaquone cannot be passed on by mosquitoes.

Atovaquone was introduced in 2000 and is safe for pregnant women and children, but it was largely phased out of use because resistance was initially observed.

The new study revealed that 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.

The results, published in the U.S. journal Science, were based on studying a model strain of rodent malaria and a deadly strain of human malaria.

Lead authors Professor Geoff McFadden and Dean Goodman of the University of Melbourne called it a "genetic trap" that could prove to be a significant step forward in the anti-malaria fight.

The pair, together with collaborators from Indonesia, the U.S. and Japan, investigated the evolution and life cycle of the malaria parasite for the past six years.

"These results are very exciting because the spread of drug resistance is currently destroying our ability to control malaria," said McFadden from the School of Biosciences at the University of Melbourne.

"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."

McFadden said the findings mean that the development of resistance to atovaquone "may not be a major problem" and that the drug could be more widely used in malaria control.

This is the first time that drug resistance was found unable to spread by mosquitoes, thereby preventing the re-infection of humans, the researchers said.

"Our next challenge will be to look for any spread of this drug resistance in field settings such as Kenya and Zambia," McFadden said.

"We are hopeful that with the development of cheaper generic forms of the drug atovaquone, that there is a new hope in the treatment of malaria."