A consideration of certain foods and of proximity to a previous case as factors in the etiology of pellagra

A statistical study of the foods used and of the occurrence of pellagra in six mill villages, including about 5,000 persons, failed to reveal any consistent relationship between the use of any particular food and the occurrence of pellagra. A somewhat similar statistical study of the location of domicile of old cases of pellagra in relation to domicile of the remaining population in these same mill villages has shown that new cases of pellagra developed almost exclusively in persons living in the same house with such antecedent cases or in houses next door to them. In other words, the disease spread from a preceding or antecedent case as a center, a phenomenon which can be satisfactorily explained, in our opinion, only by assuming that pellagra is an infectious disease. Apparently it is not readily transmitted to any considerable distance.