This is Shep O'Neal with the VOA Special English Health Report.

Malaria infects as many as five hundred million people every year. And more than one million people die from the disease each year. Those who do not die become seriously ill.

Southern African countries have the largest number of malaria deaths, mostly among young children. The disease is also common in Asia.

Malaria is caused by a parasite. Mosquitoes carry the infection from person to person. Researchers say the parasite is becoming increasingly resistant to older drugs used to treat the disease.

Artemisinin (ar-te-MIS-in-in) is the most effective treatment for malaria and the best drug for treating resistant forms. The World Health Organization says artemisinin should always be used in combination with other drugs to prevent drug resistance.

Artemisinin is made from the sweet wormwood plant found in China and Vietnam. But supplies of the plant are limited. And it takes a lot of plant material to get enough of the drug to treat one patient. Many suppliers are unable to meet the strong demand. The drug is costly to produce. Each treatment costs more than two dollars. So many people with malaria in developing countries are unable to get the drug. Jay Keasling is a chemical and biological engineer at the University of California at Berkeley. His research team has found a possible solution to the problem. They reported their research in the publication Nature. They placed genes from the wormwood plant into a yeast organism and got it to produce large amounts of artemisinic acid. This acid can be made into the drug artemisinin in just a few chemical steps. The researchers say this would end the need for a lot of plants.

Mr. Keasling says chemical tests show that the genetically engineered artemisinin is structurally the same as the natural form. The new drug must be tested in animals and people to make sure it is safe and effective against malaria.

So the researchers say the drug is still about five to ten years away from final development. They say their findings could reduce the cost of the active substance in artemisinin by ninety percent. This could help save many lives.

This VOA Special English Health Report was written by Cynthia Kirk. Our reports are online at voaspecialenglish.com. I’m Shep O'Neal.

malaria : 疟疾

wormwood : 苦艾

yeast : 酵母