Wetenschap - 6 december 2001

Willem Takken on the long fight against malaria

Willem Takken on the long fight against malaria

Why Wageningen should not lose its tropical orientation

Malaria is a disease of poverty. It could be controlled if enough money were spent on ridding the world of this problem. Dr Willem Takken, medical entomologist at Wageningen UR is convinced of this.

Malaria was eradicated from the Netherlands in 1960. The use of DDT (now illegal in the Netherlands) and discovery of chloroquine (a synthetic drug developed in the Second World War for treatment of soldiers) played an important role in wiping out malaria in the Netherlands. The mosquito has since recovered, but because there are no people in the Netherlands with malaria who can infect the insect there is no danger of the disease returning.

Takken: "In tropical countries there are always malaria parasite carriers present. At any moment the mosquitoes can infect the population by biting them. But there is no money available for campaigns, for instance to spray houses or drainage of breeding sites. Another way to fight infection is to use mosquito nets, treated with insecticide. If money were spent on providing everyone with a mosquito net and these were properly used it could reduce death from malaria by fifty percent. Ninety percent of the victims are children under the age of five; because of their young age they have not had the chance to build up resistance. Malaria is a disease to which people can become resistant over time. On average, children who live in tropical Africa get sick two and a half times each year. If a mother has five children, that means that at least twelve times a year she will not be able to work in her fields. And of course she may also be sick herself some of the time. The economic damage can be considerable, for the family, but also for a whole country."

Odour baits

Willem Takken is very committed to the research on the behaviour of the malaria mosquito that he and his research team carry out, and stresses the social relevance of his work. "How can you prevent people from being bitten so often by mosquitoes? We are working on 'odour baits', which attract mosquitoes and can be hung up in villages to distract them away from the humans. We also look at water management. Here in Holland the rainwater goes straight into the gutter. In much of the tropics the infrastructure is poor, so water remains in puddles - ideal breeding grounds for mosquitoes - with all the predictable results. There can be as many as a million mosquitoes in a small village."

Tropical subjects

Takken feels it is important that students can see how relevant this research is for development cooperation and tropical agriculture. He regrets that so many of the tropical disciplines previously offered at Wageningen University have disappeared.

"Fortunately there are still enough opportunities to specialise in a 'tropical subject', and students still go to the tropics for their internships. And there are many students from tropical countries who come to Wageningen to continue their education. They will benefit most from subjects which they can apply usefully once they return home. I hope also that Dutch scientists continue to work on these problems, as exchange through scientific cooperation is especially valuable."

Each year there are about 500 million cases of malaria, 100 million of which are fatal. Takken cannot understand why fighting malaria is not at the top of the priority-list of development cooperation. "Tanzania, for example, has 30 million inhabitants, and 1 dollar per head is annually spent on fighting malaria. That is nothing, and now malaria also has to compete with aids for the limited funds available for health care."

Lydia Wubbenhorst

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