Proven power of philanthropists

Using human odour to catch mosquitoes

Photography: Shutterstock

Some 200 million people a year catch malaria. Hundreds of thousands die of the disease, especially in Africa. These are mind-boggling numbers that demand innovative solutions for preventing infections.

WHY THIS RESEARCH

Every year, 200 million people catch malaria from mosquito bites. Treating all those sick people is an impossible task, which is why it is so important to tackle this life-threatening disease at its source: the malaria mosquito.

IMPACT

This project enabled scientists to replicate human odour in an odour trap. The trap catches the mosquitoes at the entrance to houses and huts, preventing them from infecting people. During practical trials malaria infections were reduced by 30 per cent and the malaria mosquito population shrank by 70 per cent. What’s more, the trap makes smart use of solar power in a way that leaves enough electricity to give light to each home. This removed the need for people to use unhealthy paraffin lamps, allowed people to charge their mobile phones and enabled children to do homework after dark.

Willem Takken, professor of Medical Entomology, has devoted his entire career to finding biological methods for combating malaria. “I have always found the subject of insects sucking blood and spreading diseases fascinating. That soon brings you to malaria, given that it is such a massive problem. Here in the department, we decided to look for different ways of tackling malaria and other insect-borne diseases than insecticides. We then started looking at the key bottleneck.”

ODOUR TRAP

Takken’s group discovered information was still lacking on how often people were bitten by mosquitoes, how often that led to disease and how mosquitoes actually locate a human to bite. It turned out that mosquitos locate humans based on smell. “That was ultimately what led to the SolarMal concept: a trap based on an odour that smells the same as humans to a mosquito. The trap can be hung up at the entrance to a house so that you catch as many mosquitoes as possible before they can get at the occupants.”

The odour trap is hung up at the house entrance. Photo: Melchert Meijer zu Schlochtern

The trap requires a small fan to spread the odour, which means it runs on electricity. “We came up with the idea of linking it up to a solar panel. We deliberately chose one that was larger than strictly necessary so that it would generate enough energy to power a light in the house as well. That removes the need for unhealthy paraffin lamps, letting our mosquito traps improve people’s well-being in other ways too.”

John Loudon, COmON Foundation

‘We did something ground-breaking’

In a practical trial on the Kenyan island of Rusinga, the scientists were able to reduce the number of malaria infections by 30 per cent in the space of one year. The malaria mosquito population shrank by 70 per cent. “I am convinced that follow-up studies would let us further perfect the method and eventually achieve reductions in infections of up to 80 per cent,” Takken points out.

After the introduction of the odour-baited traps on Kenyan island of Rusinga the proportion of people with malaria was 30 per cent lower among those living in houses with a trap compared to people living in houses who were yet to receive a trap.

It was thanks to a philanthropic gift from the COmON Foundation that Professor Takken and his team were able to carry out their project. “Given its many facets and huge scope, our research would not have been possible without the donation from this foundation. Standard funding was almost impossible precisely because our project covers multiple scientific disciplines and touches on multiple issues.”

STANDARD FUNDING WAS ALMOST IMPOSSIBLE

Takken is seeing the same problem in the discussions the scientists are now conducting with the World Health Organization (WHO) about a follow-up. “The WHO is enthusiastic, yet at the same time they do not want to fund the solar panel as that counts as economic development, which is outside their scope. But we think it is precisely that combination which will persuade people in Africa to actually use the trap. It is so frustrating! This really shows how important it is to have people with the courage to fund research of this nature.”

A mosquito trap with human odour to fight malaria.

“The contact with our donor was very amicable,” says Takken. “I sensed a huge commitment on their side and we in turn felt a real obligation in terms of things like the quality of our reporting and keeping in contact. It is important for scientists to draw up a clear-cut action plan so donors can see what is happening, and in particular to show that the scientists have thought carefully about how to spend the money. We also tried to manage expectations properly throughout. Something can always go wrong — it is research, after all.”

CLEAR-CUT ACTION PLAN CREATES COMMITMENT

Takken discovered that, as long as he communicated openly with the donor and showed that the scientists were doing everything they could to make a success of the project, they were given lots of room to take the research in whatever direction was most appropriate. This included the question of disseminating and safeguarding knowledge. “I specifically said that I wanted to use this project to train young scientists, in this particular case four Kenyan PhD candidates. That is a wonderful additional result from our project: you create knowledge and expertise in the local community. This is important when taking the next steps and doing research that builds on our results so that the odour traps eventually become a fixture in the fight against malaria.”

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“We did something ground-breaking.”