Resistance to malaria drug rings alarm bells

Washington, April 8 (IANS) Resistance to anti-malarial drug artemisinin in western Thailand is sending alarm bells ringing among global experts involved in controlling and eliminating the scrouge worldwide, a new study says.

Another study, also by Texas Biomedical Research Institute and their Thai collaborators has indentified a major region of the malaria parasite genome tied to artemisinin resistance, raising hope that there may soon be effective molecular markers for monitoring the spread of resistance.

Malaria killed 655,000 people or over one per minute in 2010. Malaria deaths have declined by 30 percent over the past decade, because of effective control using treatment with combination therapies containing artemisinin, a plant-derived antimalarial drug developed in China, the journal Lancet reported.

Patients infected with malaria parasites who respond poorly to treatment have been observed in Cambodia, bringing forth a coordinated World Health Organization effort to eliminate the disease in this region, said a university statement.

From 2001 until 2010, the Texas Biomed team and collaborators studied 3,202 patients in clinics in Northwestern Thailand, 500 miles from the Cambodian focus, according to the journal Lancet.

Researchers observed a dramatic decline in the drug potency over that period. Further, by measuring drug potency in patients infected with genetically identical malaria parasites, they were able to show that the decline in potency results from the spread of resistance genes.

"Spread of drug resistant malaria parasites within Southeast Asia and overspill into sub-Saharan Africa, where most malaria deaths occur, would be a public health disaster resulting in millions of deaths," said Texas Biomed's Standwell Nkhoma, who led the study.

"The problem we have is that treatment with artemisinin-based drugs will promote spread of resistance, but there are no viable alternative treatment options in Southeast Asia," said Nkhoma.

"Our group wanted to understand what genetic changes have occurred in these parasites," said Texas Biomed's Ian Cheeseman, who led the companion study, the journal Science reported.

"This study narrows the search to a region of the parasite genome containing around 10 genes. We haven't yet found the precise changes involved, but we are getting close," said Cheeseman.