Researchers Find Key Markers For Drug-Resistant Malaria

An international team of scientists are launching a major study of drug-resistant malaria in Myanmar.

AsianScientist (Dec. 26, 2012) – Myanmar, long an isolated sovereign state, ended military rule last year and as it gradually opens up to the world, an international team of scientists coordinated by the World Health Organization (WHO) are launching a major study of potentially deadly drug-resistant malaria, a major problem in Southeast Asia.

In two studies published by other scientists in April 2012, a new type of drug-resistant malaria was identified along the border between Thailand and Myanmar, and a major genomic region underlying the drug resistance was found.

Now, the WHO-led team aims to develop tests to identify and track the spread of the artemisinin-resistant malaria in Myanmar and Southeast Asia using the new molecular markers they have identified.

Malaria is caused by a parasite transmitted in the bite of a mosquito. The disease causes fevers and other symptoms that can lead to coma and even death. There were 216 million cases of malaria globally and 655,000 deaths in 2010, according to the WHO. Artemisinin-resistant malaria is a new type of resistant malaria that reacts slowly to the artemisinin group of drugs, a first-line treatment against the deadly disease.

“Myanmar has about three percent of the Southeast Asian population, but about 20 percent of the region’s malaria,” says Dr. Christopher Plowe, leader of the Malaria Group at the University of Maryland School of Medicine’s Center for Vaccine Development. Dr. Plowe works closely with his wife, Dr. Myaing Myaing Nyunt, a Myanmar native and assistant professor at the Johns Hopkins Bloomberg School of Public Health.

Myanmar is particularly significant in the study of drug-resistant malaria because malaria cases are found throughout the country, unlike in Thailand, where the center of the nation is malaria-free, forming a potential barrier against the disease’s spread. Myanmar’s high rate of infection paves a path for resistance to spread to and from neighboring nations, Dr. Plowe explains.

“Artemisinins are our newest group of effective anti-malaria drugs and our first line of defense against this parasite, representing a huge global investment in the fight against the disease. This emerging form of artemisinin-resistant malaria, while it’s still relatively rare, is already causing treatment failures where it first appeared, in Cambodia. The concern is that we’ll lose this drug, at an immense cost of human life.”

Building upon earlier research into the genomic region underlying artemisinin resistance, the team led by Dr. Plowe now reports in the journal, the Proceedings of the National Academy of Sciences (PNAS), the identification of four promising molecular markers for artemisinin-resistant malaria.

Clinical trials of artemisinin efficacy were conducted by researchers working in Bangladesh, Western Cambodia, and areas of northern Thailand near the border with Myanmar. Using samples from the clinical trial, the researchers tested mutations throughout the malaria genome to see if they were associated with clinical resistance.

“If these markers turn out to be predictive, we can use them to track the spread of drug resistance and to help guide the malaria control program in affected countries. We want to focus limited resources on artemisinin resistance to try to stop it in its tracks before it spreads,” says Dr. Plowe.

In addition to tracking the spread of artemisinin-resistant malaria, the scientists will train local investigators in cutting-edge molecular and pharmacology lab practices to help their country cope with the problem.

The article can be found at: Takala-Harrison S et al. (2012) Genetic loci associated with delayed clearance of Plasmodium falciparum following artemisinin treatment in Southeast Asia.


Source: University of Maryland Medical Center; Photo: Bindaas Madhavi/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

David Tan is a post-doctoral researcher at the A*STAR Institute of Medical Biology, Singapore. David received a PhD in stem cell biology from the University of Cambridge, UK.

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