What are the political reasons behind the ‘cover-up’ of Pellegra?
-Americans refusal to acknowledge hunger in the political south in the early twentieth century. It is always safer, politically, to feed starving foreigners than starving Americans. In 1930, 15 years after Pellagra was diagnosed, 200,000 Americans died due to a lack of availability of ‘simple greens.’ This shows the difficulty arising between a diagnosis and a commitment to treatment. (Ethridge)
To further the point, “The Public Health Service called upon Southerners to provide local relief for the poor. However, the response of many in the South was the opposite of grateful and magnanimous. Enraged Southerners, led by South Carolina Congressman Jimmy Byrnes, denounced the negative characterization of their region and feared that it would discourage economic investment and tourism in the South. They believed that Southern pride and Southern prosperity were on the line.” (Goldberger vs. The South)
Ethridge, Elizabeth The Butterfly Caste: A Social History of Pellagra in the South. Contributions in American History. No 17. 1972
Goldberger Vs. The South: http://history.nih.gov/exhibits/goldberger/docs/south_6.htm

What role did American ideology play?
-In France in the mid- 19th century, although Pellagra was attributed to a transmission from sheep, the government ordered the reduction of cultivation of corn to allow potatoes and animal husbandry, based on the studies of Theophile Rossel. Roussel had convinced the government that social intervention was necessary when science failed. For this he won the prize in medicine by the French Academy of sciences. Also, “political geography” forces the government to encourage crops that have the greatest amount of revenue. To have a scientist proclaim that the revenue-producing crop is hurting the poor, is implausible, and was contested heavily.
Roe, Daphne A Plague of Corn: The Social History of Pellagra. Cornell University Press. Ithica, NY 1973

How are scientific and more specifically medical reports evaluated?
-I found a source on this, but so far I have been unable to access it:
Burnham JC. The evolution of editorial peer review. JAMA. 1990 Mar 9;263(10):1323-9

How to pharmaceuticals today treat a disease if it only values the poor, since they cannot pay for the cure?
-They apparently suffer the loss. I researched Merck giving away medicine for river blindness, and it has cost the company $1 billion dollars. They have not been able to make even a small amount of this back through reputation, or shareholders. The only benefit the company attains (economically) is a better quality workforce.
The acceptable face of capitalism? Dec 12th 2002 From The Economist print edition

What was done to prevent Pellagra from resurfacing later on?
The recommendation of the Food and Nutrition Board regarding the enrichment of bread and flour with thiamine, niacin, and
iron was a direct response to the Pellagra epidemic during the Depression.
Rakajumar, K. Pellagra in the United States: a historical perspective. South Med J. 2000 Mar;93(3):272-7.