Typhoid Mary

You've probably heard about Mary Mallon. She killed a lot of people, possibly more than any other American woman, but none of them was intentional, and she was never convicted of any crime. You might know her better as Typhoid Mary.

Mary emigrated from Ireland to the United States in 1884 when she was 15 years old. Beginning in about 1900, she began her career as a cook, preparing meals for affluent families in the New York City area. These families and other servents in these households began to get sick. Mary typically left employment after infecting the household and sought another cooking job, most likely less-than-forthright regarding why she had left her previous professional appointment. Between 1900 and 1907 she infected communities in Mamaroneck, Manhatten, Tuxedo Park, and Oyster Bay, each time leaving in the wake of the local epidemic that had followed her there.

These mysterious outbreaks of typhoid in New York attracted the attention of public health investigators. They soon discovered one common link to all the cases: a certain Irish immigrant chef.

Mary was among very few people classified as asymptomatic carriers of typhoid fever, and the first such carrier ever identified in the U.S. The disease is caused by the bacterium Salmonella typhi. Most people, if exposed to typhoid, will get sick. Untreated, about 20% will die. Mary may have been born carrying the pathogen, but never displayed any symptoms. Hale and healthy, death nevertheless followed Mary wherever she went.

When officials began to unravel the medical mystery, it ignited ethical and legal controversies that persist to this day. If Mary knowingly exposed all those people to typhoid, was that murder? Did the state of New York have the right to quarantine her against her will in the interest of saving countless lives?

Few people today know anyone who's ever had typhoid, but in the early 20th century, memories of devastating typhoid outbreaks were still fresh. During the Civil War, it ravaged Union and Confederate troops alike, killing an estimated 50,000 or more.

Mary was eventually confronted by health officials, quarantined, and told that she was carrying this disease asymptomatically. In the interest of public health and safety she was urged to isolate herself or submit to the removal of her gallbladder, where tests had shown the bacterium was concentrated and which may have removed her infectiousness. She refused. At the very least, she was urged to stop working as a cook. She reluctantly, and insincerely, agreed to this condition, and was released from forced quarantine.

She started taking cooking jobs again, using false names and references. Outbreaks followed and she moved on to a new job with a new name. After two people died from typhoid at a hospital where she worked as a cook, officials tracked her down again. In 1915, she was quarantined for a second time, on North Brother Island in New York City's East River, where she remained for the next 23 years, dying in 1938.

Mary was responsible for dozens of infections, and as many as 50 deaths, but never expressed any remorse for her reckless behavior. Indeed, she never accepted the theory that she was an asymptomatic carrier of the disease, despite a mountain of evidence.