The effectiveness of an anti-malarial herbal drug could be damaged by overplanting of the Chinese shrub from which it is derived, the World Health Organization (WHO) said on Monday.
The artemisia annua (sweet wormwood) shrub must be more carefully farmed to meet a growing global demand and to keep fakes off the market, the United Nations agency said.
Chinese herbalists have used leaves from the shrub to treat malaria for centuries. It is now widely regarded as the best drug to treat the disease.
Not all shrubs yield enough for the malaria-fighting compound artemisinin to be effective against the mosquito-borne disease that kills a person every 30 seconds.
WHO urged governments to work closely with farmers and drug manufacturers to accurately estimate the demand for artemisinin while avoiding over-production that could hurt crop yields.
Workers also need more technical skills to properly extract artemisinin from dried leaves, it said.
"Not all artemisinin meets the required standards to produce quality medicines," the WHO said in guidelines calling for more stringent monitoring of the plant's cultivation and collection.
"The availability of these treatments still falls short of what is needed."
Resistance to conventional anti-malarial drugs such as chloroquine or amodiaquine have triggered great demand for artemisinin therapy which the WHO has recommended since 2001 in combination with other drugs as a malaria cure.
Counterfeit and sub-standard malaria drugs have become a problem in parts of Africa and Asia and the agency said fake malaria drugs had worsened drug resistance to the disease.
Malaria infects between 300 million and 500 million people each year, killing over 1 million of them, according to WHO. About 90 percent of malaria deaths occur in sub-Saharan Africa, with most victims children under the age of five.
Source: Bio-Bio Technology