Research just published in Nature Genetics has identified three different strains of the malaria parasite that have become resistant to the drug artemisinin. All three are circulating in south-east Asia but, as yet, have not spread to Africa, where 90% of all deaths from malaria occur.
Dr Mike Brown
, Expert in Tropical Diseases at The Physicians’ Clinic explains the significance of this new research.
“We are fortunate in having artemisinin, a front-line antimalarial drug that is highly effective at treating this lethal disease. Artemisinin-based combination therapies, used alongside insecticide-treated bed nets, have had a major impact on malaria-related deaths in the tropics, to the extent that the World Health Organisation is considering that it may be possible to think in terms of ‘malaria eradication’
,” said Dr Brown.
Tracking parasites using genetic fingerprints
The authors of the Nature Genetics study, lead by Dr Olivo Miotto of the University of Oxford, studied the DNA sequence of over 800 malarial parasites from south-east Asia. The genetic fingerprints they have identified could be useful in tracking drug-resistant strains to find out if they are beginning to spread.
“So far, malaria parasites resistant to this drug have only been found in Asia, which is known as a ‘hot-spot’ for malarial resistance. The existence of these resistant strains threatens the gains that have been made in malaria control over the last few decades and it is important that they are contained if possible
,” explains Dr Brown.
Organisations in south-east Asia who are responsible for malaria control programmes are now expected to redouble their efforts to control the drug-resistant strains to stop them spreading further. “We must try to do this before this drug joins the list of other antimalarial drugs that are no longer effective treatments for the disease - there are no good alternatives available
,” Dr Brown stresses.
Malaria and artemisinin
- Malaria is one of the most common tropical diseases in the world; in 2010, almost 219 million cases of malaria were diagnosed and the disease killed 660,000 people worldwide, most of them children in Africa.
- Malaria is found in 17 countries and most of the deaths occur in Africa, particularly Nigeria and the Democratic Republic of Congo.
- The malaria parasite belongs to the Plasmodium family, with Plasmodium falciparum and Plasmodium vivax responsible for most cases of malaria in people. The tiny parasite is carried in the gut of the Anopheles mosquito, which spreads the parasite to humans when it bites and sucks blood.
- Infection with the malaria parasite causes an acute fever. If untreated, it can be lethal, particularly in children and vulnerable adults.
- Treatments for malaria have included choroquine and sulphadoxine-pyrimethamine, which were successful for a time but the parasite had become resistant to both by the 1980s.
- The current front-line treatment, artemisinin-based combination therapy, or ACT, is very successful and has so far kept resistance in check.
- If artemisinin resistance did become widespread, malaria would be difficult to control and no new malaria drugs are expected to become available for at least 5 years.