Countries will have to consider the possibility of revising treatment strategy to counter drug resistance, says study
Researchers from UK’s Oxford University have found that drug resistant malarial parasites have reached within 25 km of the Indian border. Their study, published online on February 19, 2015, in Lancet Infectious Diseases, suggests that resistance to artemisinin– the frontline treatment against malarial infection—has the potential to enter the Indian subcontinent and spread to Africa. The situation could be exacerbated with an increase in international travel and migration.
During the study, 940 blood samples of patients across 55 malarial treatment centres in 10 administrative regions of Myanmar and relevant border regions in Thailand and Bangladesh were collected. The scientists used a novel genetic technology called “molecular epidemiological surveillance” to see if the parasites were drug-resistant or not, an attribute related to the presence of mutations in the kelch gene (K13) of the parasite.
Using this information, the research team developed maps employing geo-spatial tools to display the predicted extent and geographic route of artemisinin resistance. The maps suggest that the overall prevalence of K13 mutations was greater than 10 per cent in large areas of eastern and northern Myanmar. Resistant parasites were confirmed in Homalin, Sagaing region of Myanmar, just 25 km from the Indian border. “K13 markers have transformed our ability to monitor the spread of artemisinin resistance. However, the pace at which the spread is happening is alarming. So, we need immediate international efforts to address this issue, especially in border regions,” says Philippe Guerin, director of the Worldwide Antimalarial Resistance Network and co-author of the study.
When the first malarial drug, chloroquine was developed, researchers thought that malaria would be eradicated within years. However, the malarial parasite, Plasmodium falciparum, has proved far tougher than imagined. Drug after drug was rendered useless as the parasite evolved to evade treatment. Resistance has also always emerged in the same place—on the Cambodian-Thai border—before spreading across Asia into Africa. History is now seemingly repeating itself with artemisinin, a drug known to have transformed malarial treatment and halved malarial deaths since 2000.
Timely mapping of the spread of resistance along with a systematic review of medicine prescription will help preserve and prolong the life span of these life-saving drugs. Charles Woodrow of the Mahidol-Oxford Tropical Medicine Research Unit and Oxford University says, “The more we understand the current situation in the border regions, the better prepared we will be to adapt, devise and implement strategies in priority regions to overcome the imminent threat.” For instance, malarial resistance is lower in the mountainous western regions of Myanmar and there is no evidence of spread into Bangladesh. Therefore, efforts for stopping spread of resistance should be concentrated in the areas of eastern and northern Myanmar.
Health workers in western Cambodia experimented with revising malarial treatment. They temporarily switched to an alternative partner drug like piperaquine and saw an improvement in the effectiveness of artemisinin-based combination treatments. The study said that the use of regimens of more than three days or containing more than one partner drug in combination with artemisinin will become necessary across an expanding area of southeast Asia.
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