Drug-resistant malaria parasites "spread rapidly in Southeast Asia"

Multidrug-resistant malaria parasites are spreading rapidly in Southeast Asia, scientists said.

A new report published in The Lancet Infectious Diseases examined samples collected from malaria patients in Cambodia, Laos, Northeastern Thailand and Vietnam between 2007 and 2018.

The researchers found the new type of parasite resistant in 1,615 cases out of 1,673 whole genome sequences.

Before 2009, this type of parasite was present only in western Cambodia, but in 2016/17, its prevalence had increased to more than 50% in all the countries studied, with the exception of Laos, revealed the study.

In northeastern Thailand and Vietnam, parasites accounted for 80% of cases.

Researchers, including experts from the Wellcome Sanger Institute in the UK, said: "Our data clearly show that KEL1 / PLA1 (strain of malaria) continues to spread from western Cambodia and is now widespread. in several parts of Laos, Thailand and Vietnam, where it has often replaced native populations of previous pests.

"These results show an evolutionary process in action."

The experts told the BBC that the results raise the "terrifying prospect" that drug resistance could spread in Africa, where most cases of malaria and deaths occur.

Malaria is treated with a combination of two drugs – artemisinin and piperaquine.

The researchers said that in 2013, these drugs could not eliminate malaria infection in 46% of patients treated in western Cambodia.

Inspection of the parasite's DNA showed that resistance had spread to Cambodia and also to Laos, Thailand and Vietnam.

"This strain has spread and has gotten worse," Dr. Roberto Amato of the Wellcome Sanger Institute told BBC.

Professor Tran Tinh Hien, of the Clinical Research Unit of the University of Oxford, Vietnam, said: "With the spread and intensification of resistance, our findings put highlight the urgent need to adopt alternative front-line treatments. "

Professor Olivo Miotto, of the Wellcome Sanger Institute and Oxford University, told the BBC: "This strain of high-performance resistant parasite is able to invade new territories and acquire new genetic properties, opening up the terrifying prospect of its spread in Africa, where cases of malaria, as was the case for chloroquine resistance in the 1980s ".

However, Professor Colin Sutherland, from the London School of Hygiene and Tropical Medicine, said that while the drug-resistant parasite has undoubtedly spread, it does not necessarily represent a global threat.

The World Health Organization (WHO) estimates that there were 435,000 deaths from malaria worldwide in 2017, including 403,000 in Africa.