Este Article no existe en su idioma, Ver en: English (en),
O usar Google Translate:  
Escritor: Martin Price, Ph.D.
Publicado: 1/4/2009


Artemisia is now a commercial crop in East Africa

In EDN 95, ECHO discussed how to grow and use leaves of artemisia as part of malaria treatment by those who have no access to commercial drugs. East African farmers have now become key suppliers of artemisia leaves for the pharmaceutical industry. The following comments are taken from a report on the IRIN website (IRIN is the humanitarian news and analysis service of the UN Office for the Coordination of Humanitarian Affairs. Articles cover a wide range of subjects of interest to the development community.)

Artemisia annua cultivation now supports at least 4,000 smallholder farmers growing more than 4,000 ha of the cash crop in 2009, up from 2,000-3,000 ha last year. . . . [Large commercial cultivation was started] with grants from the UK’s Department for International Development (DFID) and later Novartis, the Swiss multinational pharmaceutical company . . . in 2004 in Kenya, Uganda and Tanzania. . . .In 2007, an artemisinin extraction plant was built in Kenya that supplied Novartis with enough artemisinin for more than 22 million artemisinin-based combination drug therapies. Smallholder farmers are paid “between $550-$600/tonne of dry leaf. . . . One hectare can bring in up to 2T of dry leaves and is usually cultivated without the use of much fertilizer or pest problems.”

Parasites may be developing resistance to artemisinin, the best drug used to treat malaria

According to the New York Times, “The parasite that causes the deadliest form of malaria is showing the first signs of resistance to the best new drug [artemisinin] against it” and “increased efforts are needed to prevent drug-resistant malaria [from spreading around the world.]” The Times article points out that “several times in the past, [the] area around the Thai-Cambodian border appears to have been a starting point for drug-resistant strains of malaria, starting in the 1950s with the drug chloroquine. . . . It took decades for this resistance to spread across the world, so by the same token artemisinin-based drugs are almost sure to be useful for many years to come. . . . The Bill and Melinda Gates foundation . . . is giving $14 million to the Thai and Cambodian governments to help pay for a containment program.”

The research the Times article refers to is published in the New England Journal of Medicine. The study involved 94 patients from Battambang Province in Cambodia who were ill with P falciparum malaria. 60 patients received high-dose artesunate therapy (4 mg per kilogram of body weight per day, orally, for 7 days) and 34 patients received quinine (30 mg per kilogram per day) plus tetracycline (25 mg per kilogramper day) in a split dose every 8 hours for 7 days. Artesunate is made by reacting artemisinin from the artemisia plant with succinic acid to create a similar drug that is sufficiently soluble to be given by injection, although in this case it was given orally. Four of the 60 patients who received artesunate had reemergencemalaria between days 21 and 28 after the start of treatment; two of these patients (3.3%) were classified as having artemisinin-resistant infections, but they were eventually cured. It now takes 120 hours to clear the blood of parasites, compared to 48 hours just a few years ago.

The New York Times article concludes with a quote from Dr. Nicholas White, a malaria expert who is chairman of a joint research program between Oxford University and Mahidol University in Thailand. “This is not the death knell of artemisinin. The drug still works in Cambodia, maybe not as well as before.” But resistant parasites are developing and could spread. The authors of the article in the New England Journal of Medicine recommend that “artemisinin monotherapy should not be used in areas where malaria is endemic; it requires an extended administration period and may lead to treatment failure,most frequently because of problems with compliance.” (In other words, people stopped taking the artemisinin before the recommended treatment time was over.)

Does the recommendation against treatment with artemisinin alone mean that people should not treat malaria with tea made from leaves of the artemisia plant? The German organization Anamed (Action for Natural Medicine) has been teaching how to grow and use artemisia throughout Africa for more than a decade, with considerable success. Treatments with artemisia tea cost almost nothing compared to the commercial product that is made by isolating the artemisinin from the plant and placing it (or compounds synthesized from it) in pills. Treatment with artemisinin pills plus another drug costs even more (than artemisinin alone), has a greater risk of side effects, and is even less likely to be used by impoverished populations. But is use of artemisia tea, a proven herbal treatment, placing the world at risk because resistance might develop?

We posed this question to Dr. Hans-Martin Hirt, founder and Executive Director of Anamed. In his response, Dr. Hirt pointed out that using the tea made from artemisia leaves is not a monotherapy, because artemisia tea is a combination of 10 anti-malarial products. The commercial drugs are based on only one of these (artemisinin) or a combination of artemisinin and some other drug that has been in use for some time (e.g. the drug Coartem is a combination of artemisinin and lumefantrin).

Dr. Hirt commented that he shares the concern that the malaria parasite might develop resistance to artemisinin. “But we have absolutely no fear that by using artemisia tea we are increasing this risk. The tea has been used in China for 2000 years, without resistance developing. Now the pharmaceutical industry has become involved. Drug companies have isolated artemisinin and produced tablets of this single anti-malarial component, and in less than 20 years the first signs of resistance have been observed [see article by Afonso et al]. If artemisinin were to become ineffective, then, sorry, it is industry and not natural herbal therapy that would be to blame.” To be on the safe side, he recommends that the tea be taken only to treat the disease, not as a prophylactic (i.e. taken every day to keep from getting malaria).

Dr. Hirt told ECHO that “throughout history there is in fact no record of any parasite becoming resistant to a whole plant extract. For example, there is resistance to synthetically made chloroquine, but tea made from the bark of the cinchona tree is just as effective today as it has been for hundreds of years.”

Extra information related to this article can be accessed from the online pdf version of EDN 103.

References

Afonso, A et al, 2006. Malaria parasites can develop stable resistance to artemisinin. . . Antimicrobial Agents and Chemotherapy 50: 480-489. Cited in The world of Artemisia in 44 Questions, W. Heemskirk et al, Royal Tropical Institute, Netherlands, 2006.

Fuller, T. 2009. Spread of malaria feared as drug loses potencyNew York Times January 27.

Hirt, H-M and K. Lindsey. Newsletter. 2006.

Noedl, H. et al. 2008. Evidence of artemisinin-resistant malaria in Western CambodiaThe New England Journal of Medicine 359(24): 2619-2620

Cite as:

Price, M.L. 2009. Artemisia is in the News Again. ECHO Development Notes no. 103