Researchers from UK have identified Australian researchers have identified a gene which allows the malaria parasite, Plasmodium falciparum, to develop imperviousness to antimalarial drugs.Plasmodium,is a single-celled organism which is transmitted to humans via the saliva of a biting mosquito, has historically evaded control efforts by building resistance to virtually all of the drugs used to treat malaria. It is hoped that the new discovery will lead to a new drug that will specifically combat resistance.
Dr Alan Donald, Head of the research team said the finding has been a long time coming. About twelve years ago we discovered this gene and suggested that it might be involved in drug resistance, but another report from another laboratory said that it was not involved. The mutations are in the gene pfmdr1, which encodes for the protein P-glycoprotein homologue 1 (Pgh1). This protein qualifies the parasitic cell to thrive in higher concentrations of antimalarial drugs by stopping the drugs from accruing within the cell.The mutation helps confer resistance to the drugs mefloquine, quinine, halofantrine, chloroquine, and artemisinin. If a drug can be developed to inhibit the Pgh1 protein, the old drugs would be more effective. However, Dr Donald says other genes also contribute to imperviousness.
"It's clear that there are other genes involved as well. We're in the process of trying to identify the other genes so that we have all the knowledge and can start thinking about developing drugs on a rational basis."
In the shorter term, the discovery will mean existing drugs can be used more carefully. By conducting a genetic survey of the parasite in a particular region, the sensitivity of that population to different drugs can be determined and the drug most likely to be effective can be prescribed.
