Once contracted, ADS can spread to a medical community at large and is highly virulent and can kill millions.  In a notable case from the early 20th century the disease Pellagra was thought to be contagious, but the vector was unknown. By 1914 Pellagra reached epidemic proportions in the American South. Between 1906 and 1940 more than 3 million Americans were affected by pellagra with more than 100,000 deaths. Pellagra deaths in South Carolina numbered 1,306 during the first