International researchers confirm antimalarial drug resistant parasites in Myanmar

Over the past 12 months, recent reports have shown that artemisinin drug resistance is no longer confined to the initial hotspot on the Thai-Cambodia border and is now firmly established in many parts of the Mekong region.

A study published in The Lancet Infectious Diseases has found that the spread of artemisinin drug resistance seems to be following the same historical pathway as resistance to former frontline drugs against malaria, such as chloroquine and sulfadoxine/pyrimethamine.

The team of researchers, led by Drs Kyaw Myo Tun and Charles Woodrow, confirm that resistance is established in western Myanmar toward the border with India.

The potential spread of artemisinin resistance – the most widely used drug against malaria infection – further westward poses a serious threat to global control of malaria. If resistance spreads from Asia to the African continent, or emerges independently in Africa, as we’ve seen several times in the past, there is a chance that many millions of people will be at risk of failing malaria treatment.

"Myanmar is considered the frontline in the battle against artemisinin resistance as it forms a gateway for resistance to spread to the rest of the world,” says Dr Charles Woodrow from the Mahidol-Oxford Tropical Medicine Research Unit and senior author of the study at Oxford University. “With artemisinins we are in the unusual position of having molecular markers for resistance before resistance has spread globally. The more we understand about the current situation in the border regions, the better prepared we are to adapt and implement strategies to overcome the spread of further drug resistance.”

Using malaria DNA samples collected in centres throughout Myanmar, and neighbouring border regions, the team found that close to 40 per cent of malaria parasites near the Myanmar Northwestern border with India carried mutations in specific regions of the kelch gene (K13) of the parasite genome – known genetic markers of antimalarial drug resistance in the Mekong region.

The WWARN team of mathematical modellers worked with the research teams in Asia to develop predictive map models. Their modelling results suggest that the prevalence of these mutations in the malaria parasite population could be as high as ten per cent in areas to the North and East of Myanmar. This close to real-time information on malaria drug resistance is valuable to help predict where the resistant parasites might emerge or spread next. The data could also be used to inform patient treatment intervention strategies used by national health programmes and non-governmental organisations.

“The identification of the K13 markers of resistance has transformed our ability to monitor the spread and emergence of artemisinin resistance,” says Dr Eric Grist, Mathematical Modeller and co-author of the study. “Our maps highlight that the pace at which artemisinin resistance is spreading or emerging is concerning. We hope to continue to work with colleagues to share data and adapt our modelling approaches to support regional and national surveillance efforts.”

As well as molecular surveillance, it is becoming critical to improve the efficacy of artemisinin-based therapies through adjustments to medicine dose regimens, especially for vulnerable groups such as children and pregnant women. This will help to prolong the life-span of these important drugs and minimise the impact on patients’ lives, whilst potentially slowing the further spread or emergence of antimalarial drug resistance.

Coming soon: WWARN will release a new K13 Molecular Surveyor mapping tool in the next 2-3 weeks. Visit our website again in April to see the tool live on our website.

Publication details: Tun et al. Spread of artemisinin-resistant Plasmodium falciparum in Myanmar: a cross-sectional survey of the K13 molecular marker. Lancet Infectious Diseases. Published online February 20 2015. DOI:10.1016/S1473-3099(15)70032-0