WHO says Chinese herb beats killer malaria strain

By Philippe Naughton

GENEVA (Reuter): The World Health Organization (WHO) said recently an extract from an ancient Chinese herb has proved three times as effective as quinine in preventing deaths from drug- resistant malaria.

The herb had been especially effective in slashing malaria deaths in Vietnam, it added.

Malaria strikes 300-500 million people a year, killing from 1.5 to three million people annually, according to the WHO.

In a communique, it said the processed extract, known as Artemether, had been tested in a two-year trial in Thailand covering 97 patients with severe and complicated multi drug- resistant malaria.

Of 50 patients who received intravenous injections of quinine -- the standard therapy for severe malaria -- 18 died. Of 47 treated with intramuscular injections of Artemether, only six cases had proved fatal.

"This is very encouraging news," said WHO Director-General Hiroshi Nakajima. "In many countries malaria is worsening."

Artemether is a derivative of the Chinese herb Artemisia annua L, whose potential against malaria has been known to modern scientists for over 20 years. Called qinghaosu in Chinese, the first historical record of the herb's use dates back to 168 BC.

But hard scientific proof of its effectiveness had been lacking until now. WHO said the trial, carried out by Juntra Karbwang of Mahidol University in Bangkok, "finally clinches the case" for the extract.

Resistant

Medical experts said what was especially encouraging about the Bangkok trial was that it had been carried out in an area where the malaria parasite has become resistant to most of the commonly used drugs -- including chloroquine, mefloquine, halofantrine and even quinine.

Other trials have been completed or are underway in China, Vietnam, Brazil and several African countries.

According to the WHO, the drug has been "remarkably free of major and minor side-effects and no fatal adverse drug reactions have been reported."

The drug is produced by the Kunming Pharmaceutical Factory in China and is to be marketed internationally by the French company Rhone Poulenc Rorer Doma, WHO said. Other "artemisinin" drugs, derived from the same herb, are also being tested.

The key problem, WHO experts said, was how to prevent the main malaria parasite -- Plasmodium falciparum -- becoming resistant to Artemether as it has done in many parts of the world to other drugs.

In southeast Asia the parasite has already developed some level of resistance to all available drugs except Artemether, but WHO said resistance has been known to develop there within five years of a drug's widespread introduction.

"Such a fate for artemisinin or its derivatives would be catastrophic for malaria control worldwide," the WHO said.

Experts say the most effective way of preventing a recurrence of malaria treated by Artemether -- and ultimately a resistance to the drug -- is by combining it with another anti-malaria drug, mefloquine. But the cost of mefloquine, at around $2.40 per treatment, is prohibitive for many Third World countries.

About 90 percent of the clinical cases of malaria worldwide are in Africa, where existing drugs are still largely effective. About a million African children under five years of age die of the disease every year.

The WHO said artemisinin, or the essential oil extracted from the plant without further chemical derivation, had already been widely used in Vietnam, where it has helped reduce deaths by a factor of five combined with a government anti-malaria drive.