Malaria crisis looming: are fake drugs to blame?

The emergence of strains of malaria resistant to the most effective antimalarial drug class could be a precursor to a global health disaster, according to researchers.

Widespread counterfeiting of the artemisinin class of medicines has been a key factor in stimulating resistance, they believe. Worryingly, there are no effective alternatives to artemisinin drugs such as artesunate for the treatment of malaria either on the market or nearing the end of the drug development process.

As counterfeit medicines often contain low levels of the active ingredient, treatment courses are not powerful enough to kill off the malarial parasite but allow it to evolve genetic mutations that confer resistance.

The western region of Cambodia has tended to be the first region where drug-resistant strains of the most serious form of malaria – Plasmodium falciparum -  have tended to appear, according to Professor Nick Day, director of the Mahidol-Oxford Tropical Medicine Research Unit in the UK.

Southeast Asia was also the area where resistance to earlier generations of antimalarial drugs – chloroquine and sulfadoxine-pyrimethamine – was first encountered. The reasons for this are not clear but could be related to inefficient delivery of healthcare.

Warning signs came from an as-yet unpublished study carried out by Day’s research group. They found that patients in Cambodia needed four to five days’ treatment with the artemisin-based regimens to clear the infection, while patients in neighbouring Thailand could be cured in two or three.

In 2002, an article  published in the British Medical Journal provided insight into the scale of artesunate counterfeiting in southeast Asia, concluding that up to two-thirds of all tablets in circulation were fake.

Widespread resistance to artemisinin drugs would be nothing short of a global catastrophe, according to the World Health Organization which has long been recommended that malaria should be treated with artemisinin-based combination therapies (ACTs) in order to quell the chance of resistance developing.

Even with the current level of access to effective medicines, malaria affects 250 million people a year around the world and kills one million. Spread of resistance to the most severely-affected areas, particularly Africa where one in five children dies from the disease, could have devastating consequences.