What was Typhoid Mary's job?

Mary Mallon (September 23, 1869 – November 11, 1938), better known as Typhoid Mary, was the first person in the United States identified as an asymptomatic carrier of the pathogen associated with typhoid fever. She died after a total of nearly three decades in isolation.

From 1900 to 1907, Mallon worked as a cook in the New York City area for seven families. In 1900, she worked in Mamaroneck, New York, where, within two weeks of her employment, residents developed typhoid fever. In 1901, she moved to Manhattan, where members of the family for whom she worked developed fevers and diarrhea, and the laundress died. Mallon then went to work for a lawyer; she left after seven of the eight people in that household became ill.

She worked as a cook for the family of a wealthy New York banker, Charles Henry Warren. When the Warrens rented a house in Oyster Bay for the summer of 1906, Mallon went along too. From August 27 to September 3, six of the 11 people in the family came down with typhoid fever. The disease at that time was "unusual" in Oyster Bay, according to three medical doctors who practiced there. Mallon was subsequently hired by other families, and outbreaks followed her.

Among the infections Mallon caused, at least three deaths were attributed to her. However, because of her use of aliases and refusal to cooperate, the exact number is not known. Some have estimated that she may have caused 50 fatalities.