Malaria parasites immune to leading antimalarial drugs are rapidly invading much of Southeast Asia, new research reveals.
A new study, published in the Lancet Infectious Diseases journal, shows a strain of multidrug-resistant malaria has promptly spread from Cambodia to much of Laos, Thailand, and Vietnam. The data shows the parasite — known as KEL1/PLA1 — has also developed further mutations, which means treating it is now more complex than ever before.
"We discovered [it] had spread aggressively, replacing local malaria parasites,” Roberto Amato, who co-authored the study, said in a media release. “It has now become the dominant strain in Vietnam, Laos, and northeastern Thailand.”
The study — funded by the Bill & Melinda Gates Foundation, the Wellcome Trust, and various UK research organizations — revealed the strain makes up 80% of all malaria cases in northeastern Thailand and Vietnam. The parasite is now a largely contributing factor as to why 50% of Southeast Asian patients fail to be cured using standard antimalarial drugs.
Malaria is caused by a blood parasite carried by infected mosquitoes.
The disease is traditionally combated by mosquito nets and bug sprays and can usually be treated with drugs if detected quickly. The current treatment — a blend of artemisinin and piperaquine drugs — was first dispersed in Cambodia in 2008.
A previous Lancet journal study from 2017 revealed the strain was first recorded in western Cambodia in 2007. By 2013, it had begun to develop resistance and spread to northern Cambodia and Laos. Two years later, it was witnessed in Thailand and Vietnam.
A resistance to frontline malaria drugs can occur when poor-quality antimalarial medicines are used to treat the disease.
A 2018 report showed one-third of all malaria treatment drugs in Southeast Asia are of inferior quality, which allows germs to acquire the capacity to block the approved medicines intended to destroy them.
The rapid spread of the drug-resistant strain in Southeast Asia has raised concerns over the parasites potential reach.
"This highly successful resistant parasite strain is capable of invading new territories and acquiring new genetic properties, raising the terrifying prospect that it could spread to Africa, where most malaria cases occur," contributing report author Olivo Miotto warned.
While the expansion of the parasite is undeniable, not all scientists believe it is a major health threat.
Despite reports that malaria progress has stalled in some regions, cases in Cambodia continue to decline. The nation saw over 260,000 cases of the disease in 2008. A decade later, that figure fell to just over 36,000, the BBC reported.
The World Health Organization also reports Africa’s malaria mortality rate per 100,000 population reduced from 75 in 2010 to 44 in 2017.
"These parasites are scary beasts; there's no doubt. However, I wonder if these parasites are not very fit because the population as a whole is crashing,” Colin Sutherland, a professor at the London School of Hygiene and Tropical Medicine told the BBC, before explaining an alternative drug combination could be used as a replacement treatment.
"The implications are not as severe as we might think," he said.