CHEJU, Tanzania Ė Dutch entomologist Bart Knols has declared a war on mosquitoes and his unlikely weapon is the smell of cheese.
Knols has spent three decades researching the insects and developing ways to stop the transmission of malaria and dengue in Africa.
In his own words, he loves to research them, but prefers to eliminate them.
You are a renowned scientist for using unusual tools in the fight against malaria. Is it true that you used Limburger cheese to catch the Anopheles mosquitoes?
I have been looking at what chemicals that we give off from our skin are attracting African malaria mosquitoes. I was doing that to see if I could use these chemicals to attract mosquitoes to traps where we can kill them. When I was doing this I discovered African malaria mosquitoes have a really strong preference for biting ankles and feet of people. Different from other mosquito species. Then that crazy thought came, maybe we could use some of that cheese that smells like feet to lure African malaria mosquitoes, and it worked.
The finding earned him the IG Nobel Prize in October 2006 and, one year later, the Eijkmanm Medal in recognition of his career. What has been the impact of this discovery?
We are not working with the cheese anymore because now we know exactly which compounds are produced by the cheese. We have done chemical analysis and now we have been working with cocktails of these chemicals. In 2010, there was already a cocktail of chemicals three times more attractive than a human being.
We need a very cheap trap system. Trapís that cost $1 and that every household here (in Africa) can afford.
The proof is there, but turning it into something that can become mainstream is still for the future.
Africa continues to be the continent most punished by this disease, with 219 million people worldwide and 435,000 lives claimed in 2017 alone, mostly children, according to the latest figures from the World Health Organization. Why is malaria here stronger than in the rest of the world?
Ninety percent of all malaria is in Sub-Saharan Africa. Why? Because we have got very effective mosquitoes here, they are really good at transmitting malaria and they like to feed on people.
Here we have housing systems that are as advanced as elsewhere in the world. We have openings between the roof and the walls, cracks in the walls, open windows, torn netting, so mosquitoes get in.
You are now working on another pioneering project in Uganda to increase the use of nets. What is this new program?
One of the things that we have observed is that in places where they are really good with malaria control, even in Zanzibar, people have stopped using their nets.
They donít hear about malaria anymore. They use their bed-nets for fishing, protecting the chickens or the crops. People are really inventive when it comes to using their nets.
In an attempt to stop this, we thought that if you look at these white nets they are like a page, an unprinted page. So the idea came: what if we put a nice print on the net, would people look after their nets better?
Do you mean to decorate the mosquito nets with images?
Exactly, we have been pioneering this in Uganda, where we have a trial with 2,000 printed nets that we gave out to pregnant women, and the winner by large was a print of Jesus.
These women loved to have a print of Jesus on their nets because it would be like ďMunguĒ (God in Swahili), like god protecting them at night.
Instantly the misuse of the nets stops, no more nets used for fishing. You are not going to fish with a net with Jesus on it.
Now we are setting up a big trial in Uganda where we are trying to get money for a million nets for children between eight and fourteen years old. They choose from a book with lots of prints, so we try to give them the nets of their dreams.
Since 2000 the use of nets has greatly helped reduce the number of malaria cases saving some 7 million lives worldwide, but in the last five years the figures have stagnated. Why is this?
In a lot of countries, malaria is going up again because there is not enough funding. We are also dealing with resistance here, mosquitoes are becoming resistant to the insecticide, parasites are becoming resistant to the drugs that we are administrating, and failing health systems are not well-equipped. So we donít get the drugs to really remote areas.
How are you gonna control malaria in eastern Congo, or South Sudan, or the Central African Republic, or southern Chad or Somalia?
But other quieter countries take the lead. Right now in Zanzibar, you are involved in a new project in which drones are used to fight malaria. What is this initiative?
For us to bring malaria to even to lower numbers we have to come up with new tools, things that we can use outside the house, in the environment, and one thing you can do in the environment is to try and control the mosquito larvae.
Why? Because they behave just like the CIA.
When they are concentrated in the water, they are immobile, they cannot move anywhere or fly away and they are accessible. You can actually walk to that water and treat it.
These days we have really good biological control agents, things that you can use to kill mosquitoes in the fields that are non-toxic to humans, harmless to the environment or other aquatic organisms.
Itís so safe that you can actually drink it.
Can we predict the end of this disease in the near future?
I am an eternal optimist and believe that most of the parties that are out and about they have a true interest in getting rid of malaria in the world.
Malaria is not a tropical disease, there used to be malaria in Siberia, Canada, the United States, everywhere, but now it remains in the tropics.
More than a hundred countries have already eliminated malaria if they could do it, why canít we? It takes money, effort and a will to do it.