Plasmodium falciparum

WHO/MAP/TDR

Drugs currently used to treat people with HIV could also be used against malaria, according to scientists at the Queensland Institute of Medical Research, Australia.

The researchers, whose study will be published in December in the Journal of Infectious Diseases, say their findings are important in tropical regions where people are often infected with both HIV and malaria.

The study assessed the effect of six commonly used HIV drugs on the malaria parasite — Plasmodium falciparum — in laboratory tests. Three of the drugs stopped the parasite from growing, while three had no effect.

The drugs block an important parasite molecule and were effective against malaria parasites that are resistant to currently used drugs.

"At present, [these drugs] do not form part of the first line treatment of HIV in developing countries," says Stephen Rogerson, a malaria researcher at the University of Melbourne. "[This is] for two reasons: expense, and in many instances the need for cool storage of the drugs."

However, Rogerson told SciDev.Net, "growing evidence shows that HIV-infected people respond less well to standard malaria therapy", suggesting the need for a new class of anti-malarial drugs specifically for those with HIV.

Although the Queensland researchers do not believe that these drugs would be the first choice to initially treat malaria patients, they think they have identified a chink in the parasite's armour that could be explored for the development of new drugs.

The researchers say they are not sure exactly how the drugs act against the malaria parasite. One theory they propose is that the drugs inhibit an enzyme the parasite uses to digest haemoglobin, the pigment in human blood that allows transport of oxygen.

The next step, they say, is to test these results in patients who have both HIV and malaria to determine how the drugs work in combination with others.