The fight against sleeping sickness | Science| In-depth reporting on science and technology | DW | 11.01.2013
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The fight against sleeping sickness

European researchers have found a way to block the parasite that causes trypanosomiasis (sleeping sickness). It is estimated that up to 30,000 die in Africa, where the disease is endemic in some regions.

Researchers at the University of Giessen, Hull York Medical School, the University of Bordeaux and the University of Grenoble, have identified a protein that the inhibits energy metabolism of the parasite that causes African trypanosomiasis – commonly known as sleeping sickness. The disease can cause bouts of fatigue and disrupt the sleep cycle, and it can lead to death if left untreated.

People become infected when they are bitten by the tsetse fly, an insect that carries the parasite responsible for causing sleeping sickness. Once the parasite is in the bloodstream, it can travel into the brain and the nervous system. When that happens, it can cause fits of raging madness, daytime slumber and nighttime insomnia.

"At that stage, your chances of getting out alive are pretty low," says Sebastian Dieckmann, head of the Clinic for Tropical Medicine at Berlin's Charité Hospital.

The period of time the parasite takes to infect the brain depends on the strain – ranging from weeks to years. But the discovery of the protein that inhibits the energy metabolism of the parasite would make it extremely difficult for the parasite to survive in humans and impossible in tsetse flies.

Mariam Kapurwa, 16, left, washes milk containers in Sokoine Village, Tanzania. Tsetse eradication would allow herdspeople to own more productive livestock.

Sleeping sickness affects some of the poorest in Africa

Long wait for new treatment

It may take years before the new research can contribute to a possible treatment for sleeping sickness, which has no cure, according to Frank Voncken, the lead researcher on the project.

"This is a small step. Not a large breakthrough yet," says Voncken, who also lectures at the Hull York Medical School.

His fellow researcher, Claudia Colasante from the University of Giessen in Germany, agrees.

"It's the first piece of the puzzle, but it will be a long way until we have a drug to block the protein in a patient," she says.

Voncken believes that it might take more than ten years of research for a treatment or cure to be developed, if it ever happens. And it makes a big difference whether the parasite is in a test tube or in a real human being.

"The human body is complex. When a drug is developed to inhibit the protein we found, maybe the liver will decompose part of it," Voncken explains. "And when the parasite is already in the brain, the drug would need to cross the blood-brain barrier."

A scene from the 2011 German film Sleeping Sickness

The German film "Sleeping Sickness" promotes awareness of the illness

Sleeping sickness in Europe?

The current treatment for sleeping sickness was developed in the 1950s and 60s. And the drugs used in the second stage, when the parasites have reached the brain, contain arsenic and are toxic to the nervous system.

"The pharmaceutical industry hasn't really been interested in sleeping sickness, and hasn't put that much money behind research," says Dieckmann from Charité Hospital.

There is little money to be made. The disease affects people in some of the world's poorest countries – in regions between the Kalahari Desert in Southern Africa and the Sahara where the environment is conducive for the tsetse fly. But the number of people dying every year pales in comparison to other tropical diseases like malaria – up to 30,000 versus millions for the latter.

Still, there is a risk for everyone. Last year, three cases of sleeping sickness were reported in Europe. Tourists caught the disease while on safari in Kenya and Tanzania. Also, sleeping sickness could arrive in the northern hemisphere in the future, Frank Voncken warns.

"If climate change continues with this pace, and we don't get hard winters anymore, the tsetse fly could survive in Europe as well," he says.

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