On this day in 1869, Mary Mallon was born in County Tyrone, Ireland. As a teenager, Mallon emigrated to the U.S. According to a biography of her by Judith Walzer Leavitt, Mallon was skilled in the kitchen, and eventually found employment as a live-in cook for affluent families in New York City. Unfortunately for those who ate food that she prepared, Mallon’s body harbored the bacterium that causes typhoid fever, an unpleasant affliction characterized by fevers, abdominal pain and severe diarrhea. It is not known how she herself became infected, but one theory is that the bacterium was passed to her by her mother. Mallon, who denied ever having had typhoid fever, probably was one of the three percent of people infected with the bacteria who are asymptomatic. But she could still pass the infection to others. Additionally, she handled food and apparently was somewhat less than diligent in washing her hands after using the bathroom, which made her the perfect medium for spreading the infection to her unsuspecting clients.
Between 1900 and 1907, according to Leavitt, Mallon infected 22 people in various New York households by serving them puddings and cakes tainted with typhoid bacteria. All of them became seriously ill, and one died from disease complications. After public health investigators realized that Mallon was the common denominator in those cases, the immigrant was arrested and quarantined on the grounds of a hospital on an island in the East River. Newspapers vilified her as “Typhoid Mary,” and depicted her in cartoons as a ghoul cracking skulls instead of eggs into her skillet. Nevertheless, after three years, officials agreed to release her, on condition that she change her profession to laundress.