Eliminating Malaria: A New Approach

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ASHEVILLE, N.C. — While other scientists are working on vaccines, new drugs, genetically modified mosquitoes and lethal fungi to combat malaria, Francois H. Nosten believes eliminating malaria is possible by eliminating the parasite that causes it.

Nosten has been working for 30 years on the Thailand-Myanmar border as the director of the Shoklo Malaria Research Unit, which is Mahidol University’s faculty of Tropical Medicine’s field station.

Particular types of mosquitoes carry a tiny, single-celled parasite called Plasmodium that transmits malaria to humans. Controlling the disease is difficult because mosquitoes are becoming resistant to the chemicals used in repellents. Even more concerning, parasites are becoming increasingly more resistant to drugs; first to mefloquine and now to Artemisinin combination therapy (ACT.)

In the early 1990s, the parasite Plasmodium falciparum began building resistance to the drug used at the time named mefloquine, or better known by its brand name to the public as Lariam.

ACT use is widespread now, but its story begins in 1967, when then-chairman of China Mao Zedong began a covert mission named Project 523 to find new anti-malarial drugs. In 1971, after testing 200 herbs, his team of 600 scientists finally found that the Artemisia annua plant, also known as sweet wormwood, was the answer.

In 1981, when Nosten and his partner Nick White finally got their hands on a vial of the drug, they found that it was fast acting but left the body quickly. White decided to test it in combination with the mefloquine, which was being used at the time but was losing its efficacy to parasite resistance.

Mefloquine had the stamina that the artemisinin lacked. And so artemisinin-based combination therapy, known as ACT, was created. By 1994, after studies were completed, it was proven safe and effective.

In the 2000s however, beginning in western Cambodia, ACTs began taking longer to treat patients, which meant the parasite was evolving. Not only was the parasite taking longer to clear, it was stubborn enough in some cases that it would infect again within a month.

While conducting research in the village of Hka Naw Tah in Myanmar, Nosten noticed something revolutionary. When testing a drop of blood under a microscope, he found that about 10 to 20 percent of the population had Plasmodium in its red blood cells, indicating that they were infected.

Later, however, when Nosten began collecting about a thousand times more than the drop, the percent of people infected increased dramatically to about 60 to 80 percent of the population. He could not believe the results, so he tested repeatedly until he confirmed that it was true.

Nosten has found that curing the sick is not enough, due to the large amount of people that still carry the disease without symptoms.

With just three days of ACT, the parasites can be killed. Because malaria does not infect beings other than humans, eliminating parasites could rid regions of the parasites entirely. Other parasitic disease such as river blindness and filariasis have been combated in this fashion.

In Hka Naw Tah, Nosten is optimistic that the whole population can be treated. In other villages, however, like the one down the river, the outlook is not as promising. For political reasons, one of the factions of the Karen ethnic group refuses to participate.

Giving medicine to such a large amount of people, particularly those who are not sick, requires a great deal of trust and participation on behalf of the population.

Already 660,000 people die per year of malaria. Resistance to ACTs has increased exponentially on the Thai-Myanmar border where the Shoklo Unit is located. Nosten projects the resistance will reach India and Bangladesh in the next three to four years, and if it reaches Africa, it will be drastic.

Although Nosten is not entirely sure that this plan will work because “the effectiveness, feasibility and economics of mass treatment are still being studied,” he asks what the other options are to stop the impending spread of resistance from Asia to Africa.

The Bill & Melinda Gates Foundation has already pledged its support, but it will take the continuation of financial resources and revolutionary ideas like those of Nosten and the Gates family to combat this disease that has the protection of evolution on its side.

Sources: The New York Times, Shoklo Malaria Research Institute, Mosaic
Photo: ModernPest

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