Malaria parasite's resistance to top drug grows: WHO

A worker picks up a mosquito at Sanaria Inc. facility in Rockville, Maryland, October 26, 2007. The insects in the facility are dissected for the motherlode that they carry -- baby malaria parasites.

HONG KONG (Reuters) - The World Health Organization warned on Wednesday that the parasite which causes malaria is increasingly resistant to artemisinin, the best drug around, and failure to contain this trend would bring serious consequences.

"This (Asia Pacific) region has traditionally been the focus of resistance to antimalarial drugs and now we have artemisinin resistance primarily on the Thai-Cambodian border," said John Ehrenberg, WHO regional adviser on malaria and other vectorborne and parasitic diseases.

"If it is not contained, it can have global implications and the most serious one would be in Africa which has a high disease burden and the highest mortality rates," he told Reuters on the sidelines of a regional meeting of the WHO in Hong Kong.

Although malaria is preventable and treatable, there were still between 189 million to 327 million cases in 2006, resulting in between 610,000 to 1.2 million deaths.

Half the world's population is at risk, particularly the poor and those living in remote areas with limited healthcare access. A child dies from malaria every 30 seconds.

Artemisinin, derived from the sweet wormwood shrub, is the best drug available but misuse and over-prescription have led to the parasite becoming resistant to it.

The best way to prolong the use of the drug would be to use it in combination with other antimalarial drugs. Nearly all the

Asia Pacific region countries that suffer most from the disease pledged on Wednesday to do that.

"Experts have been calling for combined therapy to make sure this problem does not arise ... all endemic countries in the region, except one, have adopted (the plan) and we are hoping to get the 10th pretty soon," Ehrenberg said.

The 10 countries are Cambodia, China, Laos, Malaysia, Papua New Guinea, the Philippines, South Korea, Solomon Islands, Vanuatu and Vietnam. In 2008, these 10 states reported 248,141 confirmed cases of malaria and 1,005 deaths.

Under the agreement, the use of artemisinin alone for treating malaria must be banned by 2015.

All 10 states will also help fight counterfeit antimalarial drugs, again a major cause of deaths.

In recent years, parts of Asia have been awash with fake antimalarial drugs. They contain little or no active ingredient that would fight the disease and many people have died because of that. Some of the fakes have been traced back to illegal factories in China, according to experts.

"Low quality and counterfeit drugs is a serious concern ... any inadequate way of treating malaria can lead to death. Malaria kills a lot of children especially in Africa when you don't treat it properly, it leads to death," Ehrenberg said.

"Many countries rely a lot on the private sector. Unregulated drug policy can jeopardize efforts to (drug) resistance containment. Getting the private sector onboard is critical."

(Editing by Jerry Norton)