The most famous of these was Mary Mallon, better known today as Typhoid Mary . Mary was a cook who while not ill herself, was the cause of a number of outbreaks although Mary herself never believed she was the cause. At that time it was not well understood that there could be healthy carriers.
The Health Department incarcerated her in a cottage near the hospital. She was released after two years after promising not to work as a cook. For a time Mary complied, working as a laundress and other related occupations but Mary was not able to earn as much doing the other jobs and went back to cooking as a profession. She changed her name and the typhoid cases continued resulting in a number of deaths. The Health authorities again incarcerated Mary until her death.
Typhoid was fairly common in the early 1900s and before when water supplies were not chlorinated. This was particularly true when the sewage which was also not treated entered the water system and then that water was used for a town supply. An example of this is given below in a quite nice piece of public health investigation.