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Thursday, October 15, 1998 Published at 17:54 GMT 18:54 UK


Health

Can a Chinese herb win the malaria war?

The malaria parasite is spread through the saliva of mosquitos

A drug developed from a Chinese herbal remedy could be the most powerful weapon in the fight against the growing threat of malaria.


The BBC;'s Horizon on mosquitos and malaria
Chinese scientists have known about the drug, developed from the Artemesia plant, for decades.

But, according to the BBC's Horizon programme, political differences with the West have delayed its global launch for 30 years with the loss of millions of lives.

Malaria is estimated to kill 10,000 children a day worldwide.

Over this century, progress has been made in stamping out the disease only for it to develop resistance to every treatment.

Now there is more malaria than in the past and it is being found in areas where it was not seen before. Global warming could also reintroduce the bug to areas where it has been wiped out, such as Europe and the USA.

The new Chinese remedy works in a different way from other anti-malaria drugs and it is hoped this means the malaria parasite will find it difficult to develop resistance to it.

Malaria bomb

Scientists say it works like a bomb. It contains two oxygens which cause the iron wall in the malaria parasite to collapse, producing free radicals which destroy the parasite.

Malaria is full of iron from the red blood cells it feeds on.


[ image: The Artemisia plant could be the final solution for malaria]
The Artemisia plant could be the final solution for malaria
Scientists believe the new drug - known as Artemisinin - could kill the parasite before it has time to recognise the drug's structures, meaning it would never be able to develop resistance.

Despite Artemisinin being vaunted as possibly the most important anti-malaria drug, it has been around for some time.

It was developed during the cultural revolution in China in the late 1960s. Chairman Mao's rejection of Western concepts of medicine led to scientists looking at ancient Chinese herbal remedies.

They studied many types of traditional malaria cures before hitting on a recipe for tea made from the Artemesia plant.

They distilled the tea and added chemicals to try to isolate the active compound in the plant. They then manufactured that in drug form and did tests on malaria patients.

It was found that it cleared malaria parasites from their bodies faster than any other drug in history.

Politics

However, it was not until the late 1970s and early 80s that news of the discovery reached scientists outside China.

At first, scientists did not believe the results as they said much of what came out of China was not supported by hard evidence.


[ image: Dr Ying Li: the West seemed 'arrogant and contemptuous']
Dr Ying Li: the West seemed 'arrogant and contemptuous'
They also could not figure out how the drug could work.

The World Health Organisation (WHO) tried to contact Chinese scientists and officials to find out more, but drew a blank.

Dr Ying Lee, one of the scientists involved in the research into Artemisinin, said the Chinese distrusted the West.

"The foreigners seemed to be snooping. They were so arrogant and contemptuous."

The Chinese suspected the West just wanted to exploit the drug and sell it in the West.

The fact that there were several Americans on the WHO's steering board on malaria and that some were from the military did not help matters.

Washington

The American military then began an investigation to track down the Artemesia plant.

They went all over the world before they finally found the elusive plant on the banks of the Potomac River at the heart of US power in Washington DC.


[ image: Malaria kills 10,000 children a day]
Malaria kills 10,000 children a day
They then discovered it in people's gardens and began doing experiments.

All the Chinese tests had to be repeated. It was not until the mid-1990s that they discovered how the drug worked.

Armed with the new drug, the WHO is launching a campaign this year to halve the number of deaths from malaria over the next decade.

The malaria parasite has developed resistance to all previous drugs.

Until the end of the last century, it was thought that malaria was linked to foul-smelling marshland.

Its name comes from the Italian for 'bad airs'. People thought the mists around marshes caused the disease which was rampant throughout the world for thousands of years.


[ image: Dr Ronald Ross: the malaria pioneer]
Dr Ronald Ross: the malaria pioneer
But it was a British GP, Dr Ronald Ross, who hit on the science behind the disease and won a Nobel prize for his work.

Working in India in the 1890s, he came across a paper which suggested malaria was spread by mosquitoes.

He worked for years to find evidence to back this theory. Eventually he found malaria larvae in the gut of a common type of mosquito.

He studied how they moved to the mosquito's head and dropped into the salivary glands, ready to be injected into humans when the mosquito fed.

Blood loss

The mosquito feeds by inserting its mouth parts into the blood vessels and injecting anti-coagulant from its saliva to prevent blood clots.

In some places, the mosquito population is so dense that people going outside can die from blood loss.

For the female mosquito, the desire for blood is like a drug. She fills herself so full of blood that she has to rest for a day from her exertions.


[ image: A mosquito engorges itself with blood]
A mosquito engorges itself with blood
The symptoms of malaria include severe fever, heart failure and coma.

Dr Ross thought the way to tackle malaria was through eradicating mosquitos.

Despite breakthroughs, such as the development of the insecticide DDT after the Second World War, the mosquito - which can lay up to 1,000 larvae in its lifetime - has managed to elude extinction.

However, it has been wiped out in wealthy areas where governments can afford to spend millions on eradication plans.

Anti-malaria drugs

Another avenue explored in the battle against the disease has been drugs to kill the parasite.

In the 1950s, a quinine-based drug - chloraquine - was developed which proved effective against the parasite.

But since then, the parasite has developed resistance to it and other quinine-based drugs.

Scientists, used to seeing their faith in new malaria treatments founder over the last century, are crossing their fingers that the new Artemisinin drug will work.

Mosquito!, part of the Horizon series, will be shown on BBC2 at 9.25pm BST.



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