8. Mary Mallon and typhoid fever
Born in Ireland in 1869, Mary Mallon moved to the United States in the early 1880s, where she lived with relatives in New York and found work as a cook for affluent families. In 1900, she worked and resided in Mamaroneck briefly. Several residents developed typhoid fever during her brief residence there. In 1901, she relocated to Manhattan, as a live-in servant. Several members of the family developed typhoid fever, and another servant died from the illness. She took a position with another family in Manhattan, a household of eight. Of the eight, seven became ill – again with typhoid. Mary then moved to Oyster Bay, with a family of 11. Ten became ill with typhoid fever.
The pattern continued through several households where she worked. In 1907, a researcher identified Mary as the source of the typhoid outbreak, and officials quarantined her until 1910. Mary became known as Typhoid Mary, the first asymptomatic carrier of salmonella typhi identified in the United States. Released from quarantine in 1910, she worked for a time as a laundress before changing her name to Mary Brown and returning to work as a cook. In 1915, another outbreak of typhoid fever in New York was traced to her. Authorities again arrested and confined her, and she remained in quarantine for the rest of her life, dying in 1938 from complications caused by a stroke. At least 51 typhoid infections were attributed to direct contact with her, and at least three deaths. Some experts set the total infections and deaths she caused in the hundreds.