Mary Mallon was born in Northern Ireland and immigrated to New York City in 1883 at the age of fifteen where she lived with her aunt and uncle for a while. She then later began to work as a cook for wealthy families. In a seven year period between 1900 and 1907, Mary Mallon worked for seven different families, seemingly exposing each family to the typhoid disease. During her first job, the family began to develop the symptoms of typhoid just two weeks after she began working for them. This pattern continued until one family hired George Soper to investigate the incident of a typhoid outbreak in their home. George Soper was a typhoid researcher and in his findings, he traced the outbreak to the cook, Mary Mallon. Mallon had started with the family three weeks before the typhoid outbreak occurred.

Soper had a hard time finding Mary because she left her jobs after the outbreaks began without leaving a forwarding address. When he finally did track her down, she refused to give him blood, urine and stool samples, claiming that she couldn’t be the carrier because she was perfectly healthy. Admittedly, her hygiene habits were lacking and was able to spread the disease through uncooked food. In 1907, the New York City Health Department hired a doctor named Sara Josephine Baker to investigate and talk with Mary. When she still refused to comply, Baker had Mary Mallon taken into custody. She was quarantined at a hospital on North Brother Island for the next three years. During her quarantine, Mary was forced to give many blood, urine, and stool samples and it was found that she did in fact carry the typhoid bacteria in her gallbladder. The doctors offered to remove her gallbladder but Mallon refused to have the operation.

Mary Mallon had garnered so much media attention, that in 1908, she was dubbed Typhoid Mary in the Journal of the American Medical Association. She was again referred to as Typhoid Mary later on in another textbook that described the typhoid disease. Mary Mallon was the first recorded incident of someone being asymptomatic for typhoid in American history. This essentially means that she can the virus of and transmit a disease without feeling the effects of the disease or succumbing to them.

Typhoid Mary was released from the clinic on North Brother Island in 1910 and she promised to get a different job other than cooking. She became a laundress but that job was too hard and paid so little so she changed her name to Mary Brown and sought out cooking jobs again. Wherever she cooked, the families still came down with typhoid and Soper was unable to find her because she changed jobs so frequently. Finally in 1915, she took a job as a cook and at the Sloane Hospital for Women in New York City and caused another outbreak with 25 people contracting the disease and two people died from it. Mary left the hospital and police were unable to find her until they staked out the house of a friend and arrested Mary as she was bringing food to her friend. She was again brought back to North Brother Island for quarantine and again refused to have the gallbladder operation so she remained in quarantine for the rest of her life at the hospital, almost 25 years.

Mary Mallon died at the age of 69 in 1938 due to complications from pneumonia. Six years prior to her death, Mary suffered a paralyzing stroke. An autopsy of her gallbladder revealed that she did have live typhoid bacteria in it. She was cremated and her ashes are buried at Saint Raymond’s cemetery in the Bronx.