MYANMAR: WHO warns of tolerance to anti-malaria drug

YANGON, 4 February 2010 (IRIN) - Tolerance to artemisinin, the most effective anti-malarial drug available, is emerging in Myanmar and could pose a major challenge to regional malaria control, says the World Health Organization (WHO).

WHO, researchers and health officials are already trying to contain the spread of resistant strains of the plasmodium falciparum parasite along the Thai-Cambodian border.

The parasite causes the most deadly form of malaria .

Preliminary studies in 2008-09 by the Mekong countries of Cambodia, China, Lao PDR, Myanmar, Thailand and Vietnam, show tolerance elsewhere, with the drug proving less effective and taking longer than previously to kill the parasite.

The studies, presented late last year at a WHO regional workshop of health officials, show tolerance may have extended to areas along the Myanmar-Thailand, Myanmar-China and Cambodia-Vietnam borders.

WHO describes the Mekong countries as the epicentre of plasmodium falciparum resistance to anti-malarial drugs in the world, and the findings have prompted further studies over 2010 and 2011 to confirm increasing resistance.

“In this globalized economy, people move from one place to another, so parasite resistance can easily be spread to the rest of the world,” Leonard Ortega, WHO’s acting country representative in Myanmar, told IRIN.

“If those drugs are no longer effective, more people may die of malaria,” he said.

Artemisinin is normally used in combination therapy (ACT) with other drugs, although it can be prescribed on its own.

Ortega said the studies in Myanmar had shown that parasites were still detected in some cases after treatment, taking more than a benchmark three days to be cleared.

“This is an indication that there is resistance, but this year we will try to confirm that,” he said, adding that plans will soon be under way for containment of the parasite, which is spread by mobile populations such as migrant workers.

“We don’t need to wait until we confirm. We know from history - and there is now evidence at the Thai-Cambodia border - that there is resistance to artemisinin, so we believe it is already here,” he said.

Factors in resistance

In Myanmar, evidence of a tolerance to ACTs, with longer times for the parasite to be cleared and decreasing effectiveness, has been seen in Kawthaung town in the southeast, along the border with Thailand, and in southern Mon State, said Ortega.

As with the Thai-Cambodia situation, tolerance may be due to the use of counterfeit or substandard drugs which expose the parasite to lower doses of artemisinin, thereby enabling it to become resistant.

Malaria patients may also not be completing the full three-day ACT courses, while health service providers, such as doctors, are not following the national malaria treatment guidelines recommended by WHO, said Ortega.

“On the part of the service providers, we have evidence that they don’t give the complete treatment,” he said.

Instead of handing over a full course of drugs to patients, private general practitioners are cutting up the medicine packs to dole out drugs by the day, probably to increase their profits, he said.

This, in turn, deters patients from completing drug treatment courses, many of whom are the rural poor and lack the means to travel for repeat practitioner visits.

Containment challenges

Along with diseases such as tuberculosis and HIV/AIDS, malaria is a leading cause of mortality in Myanmar, according to WHO.

Despite this, resources to treat malaria and to control its spread are limited.

“People already own mosquito nets, but they are not treated with insecticide, so it’s not effective in preventing malaria,” said Ortega.

“We estimate that around nine million mosquito nets are available at the household level, but only 6 percent are treated with insecticides,” he said.

In addition, only around 500,000 ACT courses are available annually - a fraction of what is needed to treat an estimated 8.5 million malaria cases.

“There is a huge gap in terms of drugs available and prevention,” he said.