Final answer:
George Soper's investigations traced the Oyster Bay Typhoid Fever outbreak to Mary Mallon, who was an asymptomatic carrier of the disease, highlighting the importance of sanitation and hygiene in disease prevention.
Step-by-step explanation:
In his investigation of Typhoid Mary's role in the outbreak of Typhoid Fever in Oyster Bay, George Soper concluded that the most likely source of the contamination that led to the infection of the household members was Mary Mallon herself, who was a carrier of the Salmonella enterica serovar Typhi bacterium, the causative agent of Typhoid fever. Mallon was asymptomatic, meaning she carried and could transmit the bacteria without showing any symptoms herself - a concept that was groundbreaking at that time. Cooking for various households, Mallon unintentionally spread typhoid to many individuals because the bacteria are typically spread by eating or drinking food or water contaminated with the feces of an infected person. By linking Mallon to dozens of cases, Soper's findings emphasized the crucial nature of proper hygiene and sanitation in preventing disease transmission.