Louis Sambon and the Clash of Pellagra Etiologies in Italy and the United States, 1905-14

This article explores the extent to which the bacterial concept of disease acted as an obstacle to the understanding of deficiency diseases, by focusing on explorations into the cause of pellagra in the early twentieth century. In 1900, pellagra had been epidemic in Italy for 150 years and was soon to become so in the United States, yet the responses of medical investigators differed substantially. To account for these, the article reconstructs the sharply contrasting reactions to a provocative theory proposed by Louis Sambon. Applying a tropical diseases approach to pellagra, Sambon argued that pellagra had nothing at all to do with maize consumption, as the Italians had long thought, but was caused by the bite of a parasite-carrying insect. Italian pellagrologists, involved in a dogmatic quest for a toxin in maize, and with pellagra rates there on the decline, marginalized the Sambon hypothesis. By contrast, in the United States, with pellagra on the rise, the dominant infectious paradigm put Sambon center stage, his proposed etiology shaping the earliest American investigations. When the deficiency disease concept gained currency in 1913, the relatively closed world of Italian pellagrology was wrong-footed, while the more open-ended U.S. community was better able to follow up the new lead. The article discusses what these shifts and the resulting controversies reveal about the medical contexts. The actor-centered approach, with reaction to Sambon's intervention as a kind of test-case, is the key to understanding these controversies and why they mattered.