Jan 11, 2018

Scientists find new genetic sources for malaria's drug resistance

The Plasmodium falciparum parasite that causes malaria.

The Plasmodium falciparum parasite that causes malaria. Credit: Mae Melvin / CDC

Scientists have found new genetic mutations that enable the malaria-causing parasite to resist current treatments. It could lead to the next generation of more effective antimalarial drugs, according to a study published Thursday in Science.

Why this matters: In 2016, malaria caused 445,000 deaths from the 216 million cases recorded and the WHO now says we are no longer making progress in the fight against the disease. The Plasmodium falciparum parasite, which causes the severest form of malaria, has become more resistant to current drug regimes.

What they did: Over a five year period, the international team conducted a genome analysis of 262 parasites resistant to 37 different types of drugs.

  • They found hundreds of changes in 83 key genes associated with drug resistance.
  • In the lab, they used clones of the parasites and sped up the process of evolving resistance while monitoring the genetic changes.
"It took decades to  find the chloroquine resistance genetic marker, and just a few years ago we were so impressed that the marker for artemisinin resistance was identified in just five years. Here, these approaches have been scaled up to identify hundreds of putative markers in scores of genes, incredibly quickly."
— Christopher Plowe, director of Duke Global Health Institute who was not part of the study, tells Axios

Yes, but: One of the limitations is too many possible target choices can make it difficult to narrow the focus of further research.

What's next: Johns Hopkins Medicine's David Sullivan, who was not part of this study, says the dataset is a good foundation. "After this tour de force there will be incremental add ons," he says.

Current treatments: Drug combinations based on chloroquine and artemisinin are typically used to treat malaria, but there are increasing reports of resistance, they can have side effects and often they don't eradicate the parasite completely allowing it to be transmitted.

Researchers are also trying to develop a malaria vaccine, but preliminary indications show the rapid evolution of the parasite could make it difficult to make an effective vaccine. "An effective vaccine is still years away," says Sullivan.

The goal: "We are trying to find the next generation of medicines that are vastly superior to what we have now," says Elizabeth Winzeler, study author and director of translational health at UC San Diego's School of Medicine, who hopes new drug targets will lead to the elimination of malaria in ten to fifteen years.

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