Mary Mallon, commonly nicknamed as Typhoid Mary, the most dangerous woman in America was identified as an asymptomatic carrier of the pathogen associated with typhoid fever.
As a typhoid carrier, she spread typhoid to others in a time before antibiotics were discovered and typhoid had a high fatality rate.
Mary Mallon was a cook in New York. She had a typhoid fever earlier in her life and later recovered from it. Even though Mary was healthy, she still carried the bacteria in her body and infected those who ate her cooking.