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doi:10.1038/nindia.2017.73 Published online 29 June 2017

Researchers hunting for artemisinin-resistant malarial strains in India

K. S. Jayaraman

A community health worker inspects a bed net during a community survey in in rural Assam.
© P. K. Mohapatra
The emergence of a probable new challenge for malaria control in India — resistance of patients to the best known anti-malarial drug artemesinin — is causing concern among public health professionals and researchers. Scientists have now mounted a hunt for artemisinin-resistant strains in India, already identified in some Southeast Asian countries.

Artemisinin resistance is one of the issues that will be probed by the U. S. National Institutes of Health (NIH), which has renewed a major grant for malaria research in India being carried out in partnership with the National Institute of Malaria Research (NIMR) in New Delhi. The initiative — Malaria Evolution in South Asia, first funded in 2010 — will  receive a fresh tranche of $9.3 million over the next seven years, beginning July 20171.

"The Indian government and the South Asia International Center of Excellence for Malaria Research (ICEMR) are on the lookout for artemisinin resistance among patients in northeastern and eastern India," Pradipsinh Rathod, a University of Washington professor of chemistry and director of the South Asia ICEMR project, told Nature India.

"Our bet is that north east India is more likely to have artemisinin-resistant parasites due to its proximity to neighbouring Southeast Asia where artemisinin resistance has been established," Rathod said, "but we have also invested in other sites across India, in part because we don't know if resistant strains may have started to diffuse across India." 

"Till date we have not detected resistant parasites by any criteria but the border areas and other sites need to be closely monitored," added Neena Valecha, director of NIMR. "And this is being done through the South Asia-ICEMR and other programmes. Continuation of the grant will help answer many unanswered questions that have implications on malaria control," she told Nature India.

The Center is also looking for parasites that mutate at extraordinary rates, as seen in Southeast Asia. "By getting a clearer picture of malaria in India, we are 'closing the gap' on how this complex parasite behaves globally. India is a country of critical importance for understanding the spread of virulent malaria globally," Rathod said.

Biochemist Govindarajan Padmanabhan, a leading malaria researcher at the Indian Institute of Science in Bengaluru says the probe on artemisinin-resistant strains in India is timely. "The study is important, since it provides a glimpse of the complexity of malaria in India. The entry of artemisinin resistance into India can be a disaster. It has already spread to Myanmar and perhaps is already inside India. This group is better equipped to trace such an event," he told Nature India.

According to Rathod, India had an estimated 13 million cases of malaria in 2015 and more than 90 percent of its 1.3 billion people live in areas with a risk of malaria transmission. 

"While most deaths caused by drug-resistant strains of malaria have occurred in Africa, most drug-resistant parasites arise first in Southeast Asia. Drug resistance in India is important to India but also to the world since India sits in the middle of the malaria corridor that cuts from Southeast Asia to Africa," he said.

The picture of malaria in India is one of diversity, says Laura Chery, the South Asia ICEMR's associate director. "There is enormous variation in the prevalence of malaria around the country, in levels of immunity and in the species of mosquitoes that spread the disease."

Besides researchers from the UW, the South Asia ICEMR project also includes scientists from Harvard and Stanford Universities and the Fred Hutchinson Cancer Research Center in Seattle, and a large contingent of scientists, clinicians and field workers from six sites across India. In its first phase, the project has developed infrastructure in Goa, Dibrugarh, Ranchi and Wardha to carry out studies on genetic plasticity of malaria parasite, drug resistance and vector compatibility. 

Rathod said that during its first seven years the project made the surprising finding2 that malaria parasites in India show more genetic diversity than parasites in the rest of the world combined. "As a consequence, some standard laboratory tests developed elsewhere in the world to study drug resistance do not accurately predict whether Indian parasites will show drug resistance."

However, some scientists are not upbeat about the ground level implementation of malaria control strategies in India. Payyalore Rajagopalan, former director of Vector Control Research Centre in Pondicherry is skeptical. "Such collaborations do result in paper publication but are not helping in malaria control," he said. "What we need is operational research that will help us devise better strategies for mosquito control within the available budget."


References

1. Malaria evolution in South Asia. South Asia International Center of Excellence for Malaria Research. Link
2. Kumar S. et al. Distinct genomic architecture of Plasmodium falciparum populations from South Asia. Mol. Biochem. Parasitol. (2016) doi: 10.1016/j.molbiopara.2016.07.005