Final answer:
Pellagra was eradicated in the United States through improved nutrition, niacin fortification of foods, and public education. Other diseases like smallpox, polio, and malaria were vastly reduced or eradicated through vaccination programs, the use of insecticides, drainage of swamps, improved sanitation, and antibiotics.
Step-by-step explanation:
The resolution of the pellagra situation in the United States can be attributed to a combination of public health measures, improved nutrition, and specifically the discovery of the role of niacin (vitamin B3) deficiency in causing the disease. Upon this discovery, efforts were made to ensure that foods were fortified with niacin and public education campaigns were implemented to raise awareness about the importance of a balanced diet. The situation was resolved by increasing the niacin content in diets, either through direct supplementation or through the fortification of foods.
Similar strategies have been used to combat other diseases. For instance, vaccination programs and vector control measures helped reduce the incidence of devastating diseases like smallpox, polio, and malaria. Government-led efforts, such as the widespread use of DDT to control mosquitos carrying malaria, and the draining of swamp areas that served as breeding grounds for these mosquitos, were pivotal in eradicating or controlling these diseases. Alongside these efforts, improved sanitation and the use of antibiotics have further lessened the impact of infectious diseases.