"Typhoid Mary" refers to Mary Mallon, an Irish immigrant who became the first identified asymptomatic carrier of Salmonella typhi, the bacteria that causes typhoid fever. In the early 1900s, she worked as a cook in New York and unknowingly infected several people, leading to outbreaks of the disease. Her case highlighted the importance of sanitation and public health measures. The term "Typhoid Mary" has since evolved into a symbol for individuals who unknowingly spread disease or harmful ideas. It serves as a reminder of the potential consequences of ignoring public health guidelines and the need for awareness in preventing the spread of infections.