Mary Mallon was a "healthy carrier" of an infectious disease, the first ever reported and observed in the New World. But, since then, and throughout the first two decades of the 20th century, more than 100 people were added annually to the rolls of "healthy carriers" of typhoid in New-York alone. Moreover, though she infected 47 people with typhoid fever (11 of which were members of one family and their hired help) - only 3 of her inadvertent victims died. Tony Labella, another carrier, caused the death of 5 people (of 122 he had infected). But the nickname of this New York City, fiery Irish immigrant cook - Typhoid Mary - was widely dreaded in the early 1900s. Immune to the disease herself, she was the perfect carrier through her contaminated food. Private investigators hired in 1906 to find the source of the epidemic failed. George Soper, a civil engineer, traced it back to 37-years old Mallon. When he confronted her with his suspicions and asked for samples of her blood and stool, she advanced on him with a carving knife. She similarly lunged with a "long kitchen knife" at policemen who accompanied visiting health officials. Having been found hiding in an areaway closet, under the staircase outside, on a neighbour's property, she was ultimately subdued. Attempts to cure her with Hexamethylenamin, laxatives, Urotropin, and brewer's yeast failed. She was quarantined in 1907 for a period of three years by health officials. She was released in February 1910 when she pledged not to prepare food for others again, to observe some rules of hygiene, to provide periodic fecal samples, and to notify the health department on changes of her address. She sued the Board of Health of the City of New York in 1909. Weekly stool samples she sent to a private lab came consistently clean - while the same stool, analyzed by the department's own labs, turned out to be mostly infected with typhoid bacilli!!! She protested her innocence: "This contention that I am a perpetual menace in the spread of typhoid germs is not true. My own doctors say I have no typhoid germs. I am an innocent human being. I have committed no crime and I am treated like an outcast - a criminal. It is unjust, outrageous, uncivilized. It seems incredible that in a Christian community a defenseless woman can be treated in this manner." She lost the case though, in some respects, she was treated unfairly. Alphonse Cotils, another typhoid carrier, a restaurant and bakery owner who repeatedly violated his pledge not to prepare food for his clientele, got away with a mere reprimand. In 1911, inoculation for typhoid became publicly available - but few bothered as the disease had only a 10% fatality rate. Mallon reneged on her promises to the Health Board and in 1915 - using the pseudonym Ms. Brown - infected mothers and their newborns with typhoid at the Sloane Maternity Hospital in Manhattan where she worked as a cook. Twenty five people caught the fever and two of them died. She spent the next 23 years - until her death in 1938 - with her dog in quarantine at Riverside Hospital in North Brother Island. She became a nurse, hospital help, and a kind of lab technician. After a massive stroke she suffered in 1932, she was transferred to the children's ward.