Malaria: Artemisinin resistance happens in Africa

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[KIGALI] Cases of resistance to the antimalarial drug artemisinin have been identified in Rwanda. This “major public health threat” was first discovered in Africa.

Artemisinin resistance is widespread in Southeast Asia, but researchers say it has not yet been reported in Africa, where 93 percent of the 228 million malaria cases worldwide and 94 percent of the more than 400,000 deaths occur each year.

Chloroquine was the first-line therapy of choice for malaria in the 1960s, before resistance developed in the Greater Mekong sub-region and spread to Africa. This was followed by resistance to pyrimethamine, which is used in conjunction with sulfadoxine, says the research team from institutes such as the Rwanda Biomedical Center (RBC), the Pasteur Institute and the World Health Organization.

“This new resistance to artemisinin can be traced back to other biological and environmental factors. The key right now is to look for alternatives with new therapeutic tools.”

Patience Nkusi, Kigali University Teaching Hospital

“It is believed that the lost clinical efficacy of these compounds contributed to millions of additional malaria deaths in young African children in the 1980s,” say the researchers. “This study clearly shows early warning signs of [artemisinin resistance] in Rwanda. “

Improved access to artemisinin-based combination therapies recommended by the WHO in malaria-endemic countries has been “an integral part of the remarkable success in reducing the global malaria burden over the past 15 years,” according to the WHO.

But now, the spread or independent emergence of artemisinin resistance could pose a global public health threat as no alternative treatment is as efficient or tolerable, according to the WHO.

Contain resistance

Without effective strategies to contain the spread in Rwanda and neighboring countries, there could soon be spikes in resistance to artemisinin-based combination therapy partner drugs, say the researchers, led by Aline Uwimana, head of the RBC’s malaria case management division.

This would lead to high treatment failure rates similar to those in Southeast Asia. A 2016 study predicts that this could mean an additional 78 million cases of malaria for Africa over five years.

Significantly, the researchers confirmed that the resistant parasites found in Rwanda did not spread from Asia, but developed locally.

Using sweet wormwood – Artemisia annua, the plant that artemisinin is made from – as a powder or herbal tea could exacerbate emerging drug resistance, according to researchers.

Patience Nkusi, a doctor at the University of Kigali Teaching Hospital who specializes in treating parasitic infections, says, “This new resistance to artemisinin may be due to other biological and environmental factors, but the key for now is finding what Alternatives with new therapeutic instruments. “

“One of the biggest fears about this new scientific discovery is that there is no other option that will allow us to switch from artemisinin compounds to an alternative treatment for the most severe cases of malaria,” explains Nkusi.

The WHO recommends combination therapies based on artemisinin for the treatment of the forms of malaria with the highest drug resistance, particularly in sub-Saharan Africa.

Photo credit: USAID / Wendy StoneBaby behind mosquito net: Malaria remains a leading cause of disease and death in Africa

M.a bigger threat

WHO says the emergence of resistance to several drugs, including artemisinin and partner drugs, is a public health issue that threatens the sustainability of global efforts to reduce the burden of malaria.

“We need more research to better understand this mechanism of resistance to artemisinin and to propose alternatives,” says Uwimana.

According to a recent health and demography survey conducted by the Rwandan government, the number of uncomplicated malaria cases rose from around one million to 4.5 million between 2012 and 2016, while the number of severe cases rose from 9,000 to 17,000 over the same period .

While government interventions such as the mass distribution of insecticide-treated mosquito nets have significantly reduced the prevalence of malaria, scientists warn that emerging artemisinin resistance must be taken seriously.

“This new resistance to artemisinin requires that the affected countries include the most suitable combinations in their national therapy guidelines,” says Uwimana.

“The early detection of resistance offers the best chance of minimizing the deadly effects.”

This article was produced by SciDev.Net’s French edition, Sub-Saharan Africa.

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