Mary Mallon managed to infect 47 people during the course of her career as a cook. Three of them died of the disease. Between 1900 and 1907, she infected two dozen people with typhoid fever. She worked in Mamaroneck, New York for less than two weeks when residents began to succumb. She moved to Manhattan in 1901 and members of the family where she was employed started to develop fever and diarrhoea. The laundress died. She then went to work for a lawyer and managed to infect seven out of a household of eight. In 1906 she moved to Long Island. Within two weeks, six out of eleven household members were hospitalized. She changed employment again and managed to infect three more families. Her fame “is in part due to her vehement denial of her own role in causing the disease, together with her refusal to cease working”. We are more familiar with her unofficial name, as ‘Typhoid Mary’.Unclean !