Fresh Clips: Treatments for Malaria

Enlarge Image Image Gallery Sweet Annie is native to China, where it is known as qing hao. In North America, it is cultivated as a garden herb and sometimes is considered a weed. Photo by Steven Foster

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To those of us living in the United States, malaria might seem like a disease that ended with the 19th century; worldwide, it remains a major health problem.

For humanitarian reasons, malaria matters. And if you travel, malaria can become a personal issue.

According to the World Health Organization’s 2008 malaria report, nearly 1 million people died from malaria in 2006 alone and most were children younger than 5. In the United States, the Centers for Disease Control and Prevention received 1,564 reports of malaria cases in 2006; six of these cases were fatal. Most U.S. malaria cases were among travelers returning from other countries, notably tropical West Africa.

For centuries, quinine—derived from the bark of the South American cinchona tree—has been the stalwart in malaria treatment. Now, malaria has out-run the treatment and developed a resistance to this previously dependable remedy. But once again, the plant world offers hope in the form of humble, weedy Artemisia annua, also known as sweet Annie.

Malaria develops when microorganisms from various species of Plasmodium are injected in to the bloodstream by mosquitoes. Left untreated, the Plasmodium parasites stay in the blood, where they cause fevers and other flu-like symptoms, which can range from merely miserable to life-threatening. Quinine works by interfering with the parasite’s reproductive cycle.  

With quinine’s effectiveness waning, scientists looked to another medicinal herb—sweet Annie, which has been used for centuries in Traditional Chinese Medicine for fevers. Known to herbal wreath makers as sweet Annie, annual wormwood and sweet wormwood, this member of the Artemisia genus grows as a weed in North America in fallow ground, along roadsides and in barnyards and neglected gardens from Prince Edward Island to as far south as Alabama and west to Arkansas, Missouri and Kansas. In recent years, it has been widely planted in herb
gardens and has done what ambitious plants always do: escaped from cultivation and spread quickly.

In the late 1960s and early 1970s, Chinese researchers began investigating this traditional fever medicine for its potential in treating malaria. In 1972, they isolated a substance from the leaf of sweet Annie called artemisinin that was found to have significant antimalarial activity.

A new pharmacological treatment regime combines two drugs, artemether (a derivative of artemisinin from A. annua) and the drug lumefantrine. The product, known as Coartem, is manufactured by the Swiss pharmaceutical giant Novartis in partnership with Chinese interests. The artemisinin derivative has proven to be the most effective of the antimalarial drugs, and in combination with lumefantrine, has shown a 95 percent success rate in a six-dose, three-day treatment regime. The drug does not prevent malaria.

In partnership with the World Health Organization, the manufacturer has foregone profit on more than 250 million treatments that were distributed to malaria patients in developing countries, in conjunction with training programs and educational resources. More than 75 percent of the drugs have gone to children.

In April 2009, Coartem was approved for use in the United States by the Food and Drug Administration.

Recently, the World Health Organization has developed an initiative to reduce malaria cases using a fourfold approach, including distribution of long-lasting insecticidal mosquito nets; indoor residual spraying of insecticide; intermittent preventive treatment in pregnancy; and the artemisinin-based combination therapy for those who do get the disease.

This story of sweet Annie and the fight against malaria highlights the potential for traditional herbal treatments to contribute to successful drug development for diseases unresponsive to conventional treatments.

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