Fighting malaria on all fronts | Science| In-depth reporting on science and technology | DW | 24.04.2012
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Science

Fighting malaria on all fronts

Although medication is very effective these days, many still die from malaria. A comprehensive strategy including medicine for the poor, pesticides, mosquito nets and education is the only way to fight the disease.

Society is nowhere near finding a cure for malaria. The tiny parasites affect people's health in all tropical regions in the world. Malaria starts with a high fever and chills and often results in death. It can also damage kidneys and the spleen.

Around one million people die of malaria every year, half of which are children. Areas around the equator in Africa are particularly hard hit. "As a doctor, you still see a lot of patients with malaria in those countries, and a lot of those are very severe cases," said Kai Braker, who coordinates projects worldwide for Doctors without Borders. "The children are often highly anemic, they can hardly breathe. It's really terrifying," Braker said.

Poverty a key problem

In theory, the disease can be treated quite well these days. Testing for malaria can be done quickly, and there is very effective medication containing a derivative of artemisinin. But many patients do not have access to medical care. "Where Doctors without Borders work, especially, there is no health care to speak of," said Braker. And that makes malaria a disease of the poor.

anopheles mosquito

The anopheles mosquito transmits the plasmodium parasites that trigger malaria

A vicious cycle emerges: if you live in poverty, you are more likely to get malaria. Due to a lack of education, many people do not know enough about the warning signs and treatment options. On top of that, malaria affects the productivity of those areas most affected by the disease, boosting poverty even further.

It does not have to be that way. Malaria can be contained with a host of carefully planned measures, including the fight against the anopheles mosquito, which transmits the parasites that trigger malaria, as Jürgen May from the Bernhard Nocht Insitute for Tropical Medicine in Hamburg points out, adding that mosquito nets are still vital in fighting malaria.

Pesticides play key role

"If you don't get bitten, you don't get malaria," May noted. Mosquito nets for beds are particularly effective, since the anopheles mosquito likes to strike at night. "They start at dusk and reach their high point around midnight," he said. Once the sun is up, very few people get bitten. Of course, the nets should not have holes, but they should also be sprayed with insecticides. The chemicals kill the mosquitoes as soon as they settle on the net. The much-criticized pesticide DDT has proven particularly effective.

DDT was once used widely in agriculture. Traces of the pesticide found their way via food into the bloodstreams of animals as well as humans. Many birds of prey died at the time. Since then, DDT has been banned for use in farming. But it got a new lease of life when the World Health Organization started recommending spraying mosquito nets and walls with the pesticide.

A health worker spays DDT, a powerful insecticide, on the home of Maria Madonsela in Jozini, South Africa

The pesticide DDT is banned in farming, but can help contain malaria

If used correctly, it is not harmful, May explained, but very effective. In a hospital in Ghana, for example, the number of patients with malaria was reduced from 6,000 a month to just under 40 ever since the authorities started spraying homes with DDT. "I was surprised to see the pediatric ward was practically deserted," May said, adding that only five years ago, it was a different story. "Children were lying on mattresses on the floor because the hospital was so full."

Partial immunity

Adults from malaria-prone countries often develop a partial immunity to the plasmodium parasites, which means they can take a few bites without any adverse effects. "When you do large-scale blood tests in those regions, you'll find that children of school age carry the virus, but don't fall ill," May said. It acts like a permanent immunization jab. But if an adult stops being exposed to the parasites, the partial immunity stops too. "After a year or two, you're practically as vulnerable as a toddler," he explained. Many Africans who have spent time in Europe find themselves more susceptible to the disease when they go back to Africa.

Knowing this, researchers are hoping to develop new vaccines. There are already 25 different possible substances, but only one of them, called RTSS, is advanced enough to be tested. Around 16,000 people are currently taking part in an Africa-wide trial.

First results show that the vaccine can cut instances of malaria by 60 percent, which is relatively low compared with vaccines against yellow fever or tetanus, for example, which are nearly 100 percent effective.

Author: Fabian Schmidt / ng
Editor: Greg Wiser

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