You don't even need to know anything about who Typhoid Mary was to know that her life was probably pretty grim. Grim, but fascinating. Her real name was Mary Mallon, and she was an Irish immigrant who served as a cook... and she was America's first known asymptomatic carrier of typhoid fever, one of the late 19th century's worst epidemics. Her story is quite complex; she received completely inhumane treatment for her case, but her refusal to have her gallbladder (where the typhoid bacteria appeared to be living) removed, or stop working as a cook.
She adamantly denied that any outbreak of the disease was her fault, despite the pattern that emerged. She's linked to almost 50 cases of the disease and several deaths definitively, but the struggles of finding work as an Irish immigrant in New York at the time led her to believe that denying the accusations and hiding her identity were her best option.
Her work in various kitchens led to outbreaks of the disease wherever she worked. Officials think it was her peach ice cream that caused typhoid, as the peaches in it weren't cooked to a temperature that killed the bacteria. The New York City Department of Health first learned of her after members of a family in ritzy Oyster Bay started coming down with the disease. Typhoid wasn't common in Oyster Bay, so sanitary engineer George Soper was brought in to investigate. His thorough testing led to the conclusion that the family's cook at the time was the likely culprit. Mary, of course, had left by that point (as was her M.O., she would often flee after typhoid outbreaks), but Soper tracked her down.
Most famously, Mary was quarantined at North Brother Island. Today, it's a post-apocalyptic ghost town, but back in the day, it was home to Riverside Hospital, an institution that became known as the best place in town to treat quarantinable diseases; what better place to isolate those with easily-transmitted ailments than a remote island in the middle of a river? It was here that Typhoid Mary spent two long-term quarantines. Her first stint was three years long, and ended in 1910, after she promised to stop working as a cook (which she, of course, didn't keep). It was during the original stay that she earned the nickname Typhoid Mary, and it was discovered that she was an asymptomatic carrier of the disease, thanks to her infected gallbladder.
After her release, Mary Mallon worked as a laundress for awhile, but the job paid less, and she felt this to be unfair. She changed her name to Mary Brown, and took a job as a cook at the Sloane Hospital for Women (which today is the Morgan Stanley Children's Hospital). There, she infected 25 people, resulting in two deaths. She left, but the jig was up; officials knew she was the responsible party and tracked her down. She was sent back to North Brother Island, where she spent the next 23 years in isolation.
Mary died in 1938, while still in quarantine on North Brother Island. Her autopsy confirmed that typhoid bacteria had been living in her gallbladder, almost certainly causing the outbreaks. She was cremated and buried in St. Raymond's Cemetery. Since her time, leaps and bounds have been made in medicine, but it wasn't until very recently that scientists have started to understand how asymptomatic carriers of diseases occur. It's hard to know how much Mary understood about her condition (as someone who felt and appeared to be totally healthy, and was accused of being an asymptomatic carrier, which was a totally new thing at the time), but either way, she and her peach ice cream have gone down in history as a legend.