TABLE 1.
The Leading Hypotheses on Causation of Pellagra in February 1914
| Nutritional Deficiency Hypothesis | Infection Hypothesis | |
|---|---|---|
| Essence | Pellagra is caused by a monotonous diet deficient in one or more key nutrients. | Pellagra is caused by an unidentified infectious agent, possibly transmitted by an insect. |
| School of thought | Zeists (but open to the possibility that eating corn is not a prerequisite for pellagra) | Anti-Zeists (holding that pellagra has nothing to do with corn) |
| Historical context | Observations by Europeans, beginning with Gaspar Casál (1720−1735), that pellagra occurs almost exclusively in persons whose diet consists mainly of corn | Late 19th-century germ theory of disease, setting off a pursuit for infectious causes of most if not all diseases of then-unknown origin |
| Prime originator(s) | Giovanni Battista Marzari (1810) | Various Italians |
| Refinement | Pellagra is caused by vitamin deficiency (Casimir Funk, 1912) | Pellagra is transmitted by an insect, possibly a fly of the genus Simulium (Louis Sambon, 1905) |
| Chief proponents | Casimir Funk and Fleming Sandwith in Great Britain; in the United States, no clear champion although Rupert Blue, James W. Babcock, Carl Alsberg, Edward Vedder, and others mentioned the idea and many saw an analogy with beriberi | Sambon and Sir Patrick Manson in Great Britain; in the United States, members of the Thompson-McFadden Pellagra Commission (notably Joseph F. Siler and Ward J. MacNeal) and others attracted by Sambon's force of argument |
| Supporting data | Pellagra is uncommon among persons with access to a diet varied with meat, milk, and leafy vegetables. If caught early, pellagra responds to treatment that includes a varied diet. | In Italy, according to Sambon, pellagra occurs mainly along the banks of fast-flowing streams teeming with Simulium larvae. A few Americans confirm this observation. |
| Opposing data | Pellagra sometimes occurs in persons with access to a varied diet; it also occurs in persons who never eat corn. Studies by the Illinois Pellagra Commission and the Thompson-McFadden Pellagra Commission point away from dietary deficiency. | Pellagra in the United States often occurs in closed institutions and places remote from fast-flowing streams. No causative organism has been convincingly demonstrated despite claims made for numerous bacteria, fungi, and parasites. |