Drug-resistant strains of malaria are spreading in Southeast Asian countries. 

Plasmodium falciparum – a parasite known for causing malaria – was found to be resistant to multiple anti-malarial drugs in Cambodia, Laos, Thailand and Vietnam, according to two studies published on Monday in The Lancet Infectious Diseases.

These drug-resistant strains of malaria called KEL1/PLA1 have also genetically mutated over the years, becoming resistant to stronger doses of the prescribed drugs.

In northeast Thailand and Vietnam, more than 80 percent of malaria parasites were resistant to a combination of artemisinin and piperaquine, a common anti-malarial medication. The strain became drug-resistant in western Cambodia in 2008.

Cambodia then replaced the medication with a stronger drug combination consisting of dihydroartemisinin-piperaquine (DHA-PPQ), but by 2013, malaria parasites had become resistant to both drugs in the western part of the country. Since then, these resistant strains have spread to other parts of Cambodia, Thailand, Vietnam, Myanmar, and Laos, the study found.

The rate for DHA-PPQ failure is at 27 percent in northeastern Cambodia, while in western Cambodia, it is 62 percent, said the study. In southwestern Vietnam it's nearly 53 percent, and 87 percent in northeastern Thailand.

"This highly successful resistant parasite strain is capable of invading new territories and acquiring new genetic properties," warned Olivo Miotto who co-led the genomic epidemiology study.

Researchers fear that the strain might spread to Africa, resulting in a large number of deaths. Similar strains of malaria resistant to the chloroquine drug in the 1980s led to a large number of deaths in the region. Globally, malaria claimed 435,000 lives in 2017, nearly 93 percent in African countries, a World Health Organization estimate said. 

Efforts to combat the disease are predominantly dependent on artemisinin combination therapies (ACTs). Malaria strains becoming resistant to both ACTs and DHA-PPQs have raised alarm among health professionals around the world. 

"With the spread and intensification of resistance, our findings highlight the urgent need to adopt alternative first-line treatments," said Professor Tran Tinh Hien, a co-author of the clinical study.

Researchers suggest abandoning widely used drug combinations in the affected Southeast Asian countries to prevent the resistant forms of malaria from spreading. 

"One option is to switch the partner drug piperaquine to a drug that is currently effective such as mefloquine or pyronaridine – as Cambodia and Thailand have already done," Tran said.

But there is a possibility that in the presence of artemisinin resistance, resistance to these partner drugs might develop rapidly as well, Tran added. 

The study's findings are based on an analysis of 1,673 P falciparum samples collected from 19 provinces across Cambodia, Laos, Thailand, and Vietnam.

(Top Image: Singer Bono attends the 2010 Malaria No More Benefit event at The IAC Building on November 8, 2010 in New York City.)