Typhoid Mary

Mary Mallon, also known as Mary Brown and famously as 'Typhoid Mary' died on this day in 1938. She was an Irish cook who moved to America in the late 1800's and one of the first people identified as an asymptomatic carrier - someone who can carry and pass on a disease without succumbing to it themselves - of a pathogen, in her case, typhoid fever. It is thought that she infected 51 people in her life, three of whom died. She was forcibly isolated twice by public health authorities after she refused to provide blood samples or cooperate.

Cases of typhoid fever followed Mallon wherever she worked as a cook, suspicions were alerted when incidents of typhoid occurred in areas when it was very rare. She died from pneumonia whilst in isolation where she had ultimately spent nearly 30 years of her life. During the post mortem, live typhoid bacteria were found in her gall bladder.