Akira Kaneko's dream: the eradication of malaria
Akira Kaneko will not rest until the island is free of malaria. After having eliminated malaria on an isolated island in the outer reaches of the global malaria epidemic, it is time for the next challenge - the severely malaria-stricken islands in Lake Victoria, Kenya.
As mosquitoes ignore human boundaries, fighting malaria might seem like a hopeless project. Many ambitious attempts to eradicate the disease in various places around the world have ended with the parasite invading once again from adjacent areas. These bitter experiences shaped his view of combating malaria, when Akira Kaneko moved to the Vanuatu group of islands in the Pacific Ocean in the 1980s.
He had been hired by WHO, the World Health Organisation, to work on the malaria control programme in the area.
"It was a demoralising time. The WHO had given up trying to eradicate malaria and focused instead on reducing the spread of the disease. Few believed that the disease could be eliminated," says Akira Kaneko, newly appointed Professor of Global Health at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.
But he knew of a boundary that mosquitoes do respect - water. A mosquito who sets off to sea will not get more than a few kilometers before it falls into the water and dies. The possibilities of using this boundary were especially good on the small island of Aneityum. Not only is it on the outer reaches of the island group, it also marks the outer boundary of the global spread of malaria. Southeast of Aneityum, there are no mosquitoes that can carry malaria. There are other malaria-stricken islands to the northwest, but Aneityum is still very isolated. The influx of potentially infected persons is limited to a few small aircraft and boats per month. The lack of road traffic means that the villages on the island are also relatively isolated from each other. The island was a perfect microcosm for combating malaria.
Akira Kaneko commenced his work and established an organisation for his project. All 718 islanders were involved. "It was very important to involve the local population. They had to understand that the project could only succeed if everyone collaborates. Even persons who do not exhibit any symptoms must take their medicine, in order to stop the parasite from spreading to others," says Akira Kaneko.
Mass-medication and mosquito nets
And as if curing people from malaria was not challenging enough - the island's mosquitoes also needed to get rid of the malaria parasite. To do this, combined measures were taken just before the rainy season, when mosquitoes breed and the malaria parasite risks being transferred from infected persons to new mosquitoes.
The islanders were weekly mass-medicated for nine weeks, in order to remove the malaria parasite form their blood. During the same period, impregnated mosquito nets were installed in their simple houses. In order to decimate the annual army of newborn mosquitoes, researchers also planted fish that like to eat mosquito larvae in ponds around the island.
There was then a long surveillance period, to ensure that the disease did not return. Anyone getting off the small plane was met, and still is to this day, by a microscopist who examines the blood of all passengers.
By the year 2000, Akira Kaneko and his colleagues could report in The Lancet that they had succeeded. No trace of the malaria parasite Plasmodium falciparum could be found in the islanders' blood samples following the mass-medication. By 1996, the other malaria parasite present in the area, Plasmodium vivax, had also disappeared completely.
"I believed it would work all along, but obviously I was overjoyed when I saw the results," says Akira Kaneko.
Aneityum has even had a small tourist boom after proclaiming the island to be free of malaria. Every other week, a boat load of travellers arrive to unwind on the small pacific island. Akira Kaneko looks pleased as he shows us diagrams of how the number of visitors has increased as the occurrence of malaria has decreased.
"It is very gratifying. Some of the tourist money goes to the malaria project and is used to prevent the disease from returning," he says.
For his next project, Akira Kaneko plans to take on an island in Lake Victoria in Kenya. The area suffers greatly from malaria, and constitutes a much bigger challenge. Vanuatu is the isolated outpost of the malaria epidemic. Lake Victoria is the opposite it was there that malaria originated with humans and spread throughout the world. The area is currently teeming with different cultures and is characterised by major genetic diversity, both amongst humans, mosquitoes and malaria parasites. This makes combating malaria a more complex project, since new medicines need to be combined, for example. Akira Kaneko has developed an action plan after several visits to the island, but the financing is still unresolved.
Many researchers have been inspired by the success on Vanuatu, and the eradication of malaria is once again a stated goal for the WHO. The obvious final question in Akira Kaneko's story is whether his methods could be used to eradicate malaria on the mainland, and maybe one day on a global basis.
"It's possible, but it won't be easy. It requires hard work, resources and money," he says.
Text: Ola Danielsson. Published in Medicinsk Vetenskap nr 4 2012