Excerpt:
Pellagra was first identified among Spanish peasants by Don Gaspar Casal in 1735. A loathsome skin disease, it was called mal de la rosa and often mistaken for leprosy. Although it was not conclusively identified in the United States until 1907, there are reports of illness that could be pellagra as far back as the 1820s. In the United States, pellagra has often been called the disease of the four D's -- dermatitis, diarrhea, dementia, and death. National data is sketchy, but by 1912, the state of South Carolina alone reported 30,000 cases and a mortality rate of 40 percent. While hardly confined to Southern states, the disease seemed especially rampant there. A worried Congress asked the Surgeon General to investigate the disease. In 1914, Joseph Goldberger was asked to head that investigation.