The land of tulips and polders: malaria in the Netherlands
Although malaria was present in central Europe since Prehistory, the worst period of malaria in Netherlands was at the beginning of the Modern Age. The country is full of harbours, channels and lakes, and from 1500 to 1750 almost every parish in Holland, especially in the coastal areas, was affected by the ‘polder fever’ or any of the other names used by the locals to refer to paludism.
In the Dutch case several factors contributed to the success to eradicate malaria. The use of Cinchona in the XVII century and quinine in the first decades of the 1800 has been essential to reduce the disease and its effects. Also several agricultural revolutions such as the introduction of the potato that deceased the malnourishment and reduced the incidence of anaemia, and the introduction of pigs that turned malaria into a zoonotic instead of a anthropic disease, helped to fight malaria. Of course, water management was one of the battles that were won to overcome paludism. The reduction of the total surface of water and the prevention of floods sensibly reduced the vector habitat. Also, the introduction of the pesticide DDT (dichlorodiphenyltrichloroethane) killed millions of Anopheles mosquitoes. Finally, the improvement of the general living conditions made eradication possible. The improvement of farmhouses pigsties separated the animals from humans and the nutrition and general health status of the Dutch people helped patients to become more resistant to the infections and their consequences. In 1970, the World Health Organisation declared the Netherlands, as one of the latest countries in Europe, as ‘malaria-free’.
When Santa Claus needed quinine: malaria in Finland
Even Finland, one of the most northern and colder countries of Europe, suffered from paludism. Malaria was prevalent in Finland in the 18th and 19th century. It was present all over country but was dramatic on the southwest islands. Malaria in Finland was an ‘indoor’ disease and the main transmission season lasted from December to May.
The vectors were Anopheles messeae and Anopheles beklemishevi and were a serious burden for the people. In some instances, the disease affected all the inhabitants of a household leaving no-one able to work, and so the fields remained unploughed and unsowed. Most of the information regarding malaria in Finland came from the famous Finnish malariologist Johan Haartman (1725-1778) who recommended the villagers to build their houses in windy places and to cut surrounding bushes. Interestingly, those advices should have been effective as they kept mosquitoes away from the houses.
The fact that the Anopheles mosquito was responsible for malaria was already known in Finland since the 1900s but unfortunately very little could be done. Malaria was officially eradicated from ‘the land of the 1000 lakes’ in 1954 In the last decade Finland only reported imported cases (33 in 2010).
Strikingly, malaria was eradicated from Finland with hardly any medical measure and without any eradication campaign. So, how did the Finnish get rid of malaria? How did malaria cases drop from 20,000 – 50,000 per 1,000,000 people to less than 1 per 1,000,000 people? As medical interventions are not obviously the main factor, we should look outside the box. And maybe this glance will help us to understand how non-medical factors can contribute to the eradication of malaria in countries were malaria is still endemic. Several elements have been studied as the change in temperatures or the reclaiming of wetlands but none of them shows a direct and clear correlation with the decline of malaria in the country. The latest studies demonstrate that the most critical issue was…the change in the size of the bedrooms. In such locations, nocturnal Anopheles transmitted malaria exclusively indoors during the cold months. During centuries the villagers slept in large rooms with entire families, even with their servants, so the mosquitoes had a large number of victims in one place to quickly spread the disease. The progressive changes in land ownership reduced the average number of inhabitants per house, from 9.5 in 1750 to 4.03 in 1950. Three centuries later the number of people per bedroom was reduced by nearly 50% and this made it far more difficult for the vector to transmit malaria. So, the sleeping habits of the Finnish made Anopheles disappear
Once again…malaria was defeated
As we can see, malaria was prevalent even in places as ‘developed’ as the Netherlands and in locations as cold and northern as Finland. But once again, we have learnt that malaria is beatable. Those two examples show us two interesting lessons; the Dutch case demonstrates that a multi-factorial epidemic as malaria should be faced with a multi-factorial strategy. All available weapons should be used; drugs, agricultural implementations, intelligent management of water resources…everything that contributes to the eradication. On the other side, Finland show us how a ‘social disease’ as malaria can be defeated with social tools.
Like my previous columns, I finish with the same conclusion: malaria is a terrible disease. It is closer to us than many of us think. It should, and could, be faced by the entire global society with its entire available means.