Anti-Malaria Plant Takes African Roots

First published in the January 2005 issue of FrontLines [PDF, 1.5MB].

The fight against malaria increasingly uses Chinese sweet wormwood, but demands for the plant have exhausted supplies, leading USAID to promote new plantings in East Africa.

The Agency is working with the World Health Organization (WHO) to transplant the ancient Chinese remedy to Africa, where the soil and climate are suitable. Artemisinin is the extract of wormwood that is useful against malaria.

Planting of 450 hectares of Artemisia annua began in Kenya in January 2005. In spring 2005, 450 hectares will be planted in Tanzania.

“By this time next year, we will be looking at the extraction of 20 metric tons of artemisinin,” said Dr. Dennis Carroll, malaria expert with the Bureau for Global Health (GH). Malaria kills more than one million people each year.

Since sweet wormwood is mainly grown in China and Vietnam, to meet growing demand USAID engaged two East African groups in December 2004 to produce artemisinin in Kenya and Tanzania.

GH and the Global Development Alliance were working with artemisia growers and several pharmaceutical companies to build artemisinin extraction facilities in Kenya and Tanzania.

The sweet wormwood plants that will be grown in East Africa are hybrids, which may produce up to twice the artemisinin as Asian plants.

An estimated 15 million malaria cases were treated in 2003 with artemisinin-based combination therapies (ACT), a three-day, fast-acting combination of several drugs that quickly kills the malaria parasite.

By the end of 2006, demand for treatment will rise to 150 million cases, according to the WHO.

“ACT has proven an extremely effective way of rapidly clearing out the parasite,” Carroll said. “Combining artemisinin with another drug means you have two modes of acting, so if 95 percent is cleared with the artemisinin that other 5 percent is taken care of by the other drug.”

USAID has supported safety and efficacy testing of ACT in Africa since 1998.

As drug-resistant malaria spread, USAID nearly quadrupled funding to fight the disease: from $22 million in 1998 to $83 million in 2004. In the past three years, the U.S. government contributed $623 million to the Global Fund for AIDS, Tuberculosis and Malaria, and gave $547 million during 2004.

Malaria infects some 300 million to 500 million people each year, while new AIDS and tuberculosis infections attack 5.3 million and 8.8 million respectively, according to the WHO.

USAID also supports the use of insecticide-treated mosquito nets, which can reduce overall child mortality by as much as 30 percent.

The Agency also funds the development of a malaria vaccine that is being field tested in Kenya and Mali.