Definition
Mary Mallon (1869-1938), infamously known as 'Typhoid Mary,' was an Irish-American cook. She was a carrier of typhoid fever but remained asymptomatic. She unknowingly spread the disease to many people. Public health officials tried to quarantine her to prevent further outbreaks. The case raised ethical questions about individual rights versus public safety. She is an example of someone who was a threat without knowing it.