How could Mary Mallon live with typhoid fever and not know it?

Mary Mallon, also known as Typhoid Mary, was an asymptomatic carrier of the typhoid fever bacteria. Asymptomatic carriers are individuals who carry and can transmit an infectious disease without experiencing any symptoms themselves. In Mary Mallon's case, she was infected with the typhoid fever bacteria, but her body was able to fight off the infection without developing the typical symptoms of the disease, such as fever, diarrhea, and abdominal pain. This allowed her to remain unaware that she was carrying and spreading the bacteria to others.

Asymptomatic carriers can play a significant role in the spread of infectious diseases because they may unknowingly transmit the infection to others who may become symptomatic and develop severe illness. Mary Mallon's case is a notable example of how asymptomatic carriers can contribute to the spread of disease and highlights the importance of public health measures to identify and monitor such individuals to prevent outbreaks.