['Intervening is representing': medical campaigns that helped identify the prevalence of hookworm].

This paper compares anti-hookworm campaigns conducted in the early twentieth century in France, Germany, Brazil and West India. The populations that suffer from hookworm are not identical in the North and in the South. In tropical and semi-tropical regions hookworm is mainly found among poor peasants and is related to lack of hygiene, while in temperate climates hookworm was a professional disease of miners, a highly organized professional segment. Nevertheless, major disparities in the pattern of hookworm control did not reflect the North-South divide, but a difference between campaigns. These aimed at the eradication of hookworm infection (Germany and West-India) and at alleviating the effects of this infection on populations (France and Brazil). Maps that represented the prevalence of hookworm mirrored the aims of the sanitary campaign in which they were used: eradication of parasitic worms versus the reduction of the handicap induced by these worms. In public health as well, representing is intervening. And vice versa: patterns of intervention shape representations.