Mary Mallon, (September 23, 1869 - November 11, 1938) also known as Typhoid Mary, was an Irish immigrant who was a carrier of typhoid fever. She was born in Ireland in 1869. She apparently contracted typhoid fever at some point but suffered only a mild case. Mary worked as a cook in New York City area between 1900 and 1907. During her working career she infected 22 people with the disease, one of whom died. Mary was a cook in a house in Mamaroneck, NY, for less than two weeks in the year 1900 when the residents came down with typhoid. She moved to employment in Manhattan in 1901, and members of that family developed fevers and diarrhea, and the laundress died. She went to work for a lawyer, until seven of the eight household members developed typhoid. Mary spent months helping to care for the people she made sick, but of course the contact made many of them worse. In 1904, she took another position on Long Island. Within two weeks, four of ten family members were hospitalized with typhoid. She changed employment, and three more households were infected.
Frequently the disease was transmitted by a dessert of iced peaches, a favorite recipe.
George Soper, a sanitary engineer hired by the landlord of a house where Mary had worked for typhoid fever victims, after careful investigation identified Mary as a carrier, and approached her with the news that she was spreading typhoid. She violently rebuffed his request for urine and stool samples, and Soper fled, later publishing his findings in the June 15, 1907 issue of the Journal of the American Medical Association. Soper brought a doctor with him on his next contact with Mallon, but was likewise rebuffed.
The New York City Health Department sent Dr. Josephine Baker to talk to Mallon, but:
- "By that time she was convinced that the law was wantonly persecuting her, when she had done nothing wrong." 
She died in 1938 of pneumonia. The autopsy revealed that her gallbladder was still actively shedding typhoid bacilli. She was buried by the Department of Health at Saint Raymond's Cemetery in the Bronx.
Part of the problems Mary had resulted from her vehement denial of the situation. She maintained she was healthy and had never had typhoid fever.
- Typhoid Mary, Captive to the Public's Health, Judith Walzer Leavitt, Beacon Press, Boston, 1996, hardcover, 331 pages, ISBN 0-8070-2102-4