World Health Organization officials say there are signs of growing drug resistance to mosquito-borne malaria, raising concern millions of people in Asia may be at risk. WHO officials say counterfeit drugs and poor storage are to blame.
The fight against malaria in Asia covers more than 20 countries within South East Asia, South Asia, Eastern Asia and Western Pacific. Each year more than two million people are at risk of contracting the illness.
The Asia region accounts for more than 60 per cent of the global population at risk of the parasite with the main focus on India, Burma, Bangladesh, Indonesia and Papua New Guinea.
But World Health Organization officials point to troubling signs a current drug combination based on artemisinin, originally drawn from a Chinese herb, is losing its potency against the malaria parasite.
Artemisinin is largely given to patients in combination with other drugs rather than by itself in a bid to preserve the drug's long term effective strength.
Eva Maria Christophel, a World Health Organization official in the Philippines, says signs of drug resistance in the Mekong river basin region along the Thai/Cambodian border and in Burma have triggered anxiety within the medical community.
"The place where we are really concerned is on the Cambodian-Thai border," said Christophel. "It would be disastrous if that spread because there's hardly anything in terms of new drugs in the pipeline for malaria or what is in the pipeline will take years, so we're really very much relying on arthemisinin based combination therapy."
The World Health Organization is concerned that drug resistance could spread from the Cambodian-Thailand border region to Africa, following a similar pattern with anti-malaria drugs such as cloroquine and sulfadoxine-pyrimethamine in the 1960s and 1970s.
In February 2009, WHO confirmed anti-malarial resistance at the Cambodian-Thailand border. But recent WHO studies found up to 20 per cent of patients at the Burma-Thailand border also showed signs of malarial parasites in the blood after the normal artemisinin combination therapy.
"We noticed years ago that the disappearance time for parasites to disappear from the blood is increasing. Usually they disappear in two days or less," said Dr. Charles Delacollette, coordinator of the Bangkok-based WHO Mekong Malaria Program. "And we observe that there are an increasing proportion of patients showing parasites, still parasites in their blood after two days of artemisinin treatment, which was not the case before."
Dr. Delacollette says the growing drug resistance is in part due to the sale of substandard and counterfeit drugs. In recent years, authorities cracked down against illegal factories in China. Meanwhile, counterfeit producers have been found elsewhere, including Cambodia and Burma.
"Drugs are not quality, the quality of the drugs sold in private sector is selling any kind of drugs which are stored in very bad conditions, so they becoming substandard and also you have sellers which are selling counterfeit - purposely made counterfeit," said Dr. Delacollette.
The World Health Organization says there are signs of drug resistance concentrated in areas of southern Vietnam as well as along the border of China and Burma.