Typhoid (also called  typhoid fever) is a bacterial disease, the transmission of which is food and drink borne in nature with symptoms including abdominal tenderness, agitation, diarrhea, bloody stool, chills, confusion, delirium, hallucinations, nose bleeds, fatigue and in severe cases, death. A typhoid vaccine was not discovered until 1911 and chloromycetin, an antibiotic specifically used in the treatment of the disease, not until 1949.

Mary Mallon, better known as Typhoid Mary, was the first person in the United States identified as an asymptomatic carrier of the pathogen associated with typhoid fever. She was believed to have infected 51 people, three of whom died, over the course of her career as a cook. She was twice forcibly isolated by public health authorities and died after a total of nearly three decades in isolation. 

Mary was born in Cookstown of County Tyrone, in what is now Northern Ireland, to John Mallon and Catharine Igo. She emigrated to the United States in 1883. She first lived with an aunt and uncle, but both died shortly after her arrival. Mary later found work as a cook for affluent families. From 1900 to 1907 Mary worked in the Greater New York area for seven families. Making ice cream became her specialty. In 1900 she worked in Mamaroneck of Westchester County where, within two weeks of her employment, local residents developed typhoid fever. In 1901 she moved to Manhattan, where members of the family for whom she cooked contracted the disease. Mary then went to work for a lawyer; she left after seven of the eight people in that household became ill. She changed jobs again, and similar occurrences happened in three more households. She worked as a cook for the family of a wealthy New Yorker, Charles Henry Warren, a vice president of the Lincoln National Bank in Manhattan and a personal banker to the Vanderbilts. The Warrens rented a house in Long Island's Oyster Bay for the summer of 1906, and when Mrs. Warren fired the cook in early August she contacted Mrs. Stricker's Servants Agency on 28th Street in Manhattan for a replacement. Mary was sent to the mansion on East Main Street and McCouns Lane and hired. From August 27th to September 3rd, starting with nine year old Margaret Warren, six of the 11 family members and servants came down with typhoid fever. Fearing contaminated drinking water as the probable cause of infection, the Warrens moved back to their Upper East Side townhouse. Mary didn't accompanying them and was subsequently hired by other families. Other outbreaks followed her. The disease at that time was unusual in Oyster Bay, according to three medical doctors who practiced there. Mr. and Mrs. George Thompson, the owners of the house, returned home from their summer cottage in the Catskills. They were unaware of what had transpired. Fearing their house was sick, with the possibility of it being condemned or even burned down by the authorities if the underlying problem could not be resolved, Mr. Thompson contacted the local health department to arrange for a thorough examination of the property. They found no evidence of sewage from the stables or cesspool leaking into the well, contaminating the water supply. Pouring fluorescein into the second floor toilet then turning on the faucets in the bathroom and kitchen downstairs and seeing the water run clean, they determined the toilet plumbing didn’t leak. Samples from the servants’ privy and the attic water storage tanks tested negative for harmful bacteria. Since nearly every other family in Oyster Bay bought their milk, cream, fruits and vegetables from the same dairies and farms the Warrens did and none was stricken ill, food eaten at the house was ruled out. The house was clean. Officials determined the outbreak was a mystery, and as the danger had passed, closed the case.

But it wasn’t for Mrs. Thompson. The house had been a wedding present and she worried about being able to rent the property the next summer, so she wanted the problem solved. Through friends the Thompsons came to know Dr. George Soper, a sanitary engineer and epidemiologist. He worked for the United States Army Sanitary Corps, having received a doctorate from the Columbia University School of Mines. By 1900 city governments throughout the country were hiring such professionals to improve living conditions and public health in an effort to curtail epidemic diseases. They designed apartment buildings with improved ventilation and flush toilets, sewer systems to dispose of human waste and planned public waterworks to provide uncontaminated drinking water. As a result of these measures the incidence of typhoid was reduced by two thirds, but still in 1906 New York City 3,467 new cases were counted with 639 resultant deaths. Mrs. Thompson asked Dr. Soper for help, and he agreed to investigate. He began by retracing the steps of the earlier investigators, thinking they may have overlooked something, but concluded they had done their work thoroughly. Dr. Soper also could not find anything wrong with the house. Studying the house’s history he learned there had been one case of typhoid five years earlier, but it had been rented out continually since with no further outbreak until the Warrens. He began to focus on their household. Traveling to their Manhattan home, Dr. Soper interviewed them to see if anyone had left Oyster Bay, reasoning that person had gotten infected elsewhere and brought the disease home. He was told no one had left the house, except for the fired cook, who never returned. Her replacement began work on August 4th, three weeks before Margaret became ill. This new cook made homemade ice cream with fresh peaches, which she served to all family members and servants on August 20th. Dr. Soper thought he had his likely suspect. Although apparently healthy, Mary’s intestines and gall bladder must be full of typhoid bacteria, which passed in urine or fecal matter to her hands after using the toilet (he assumed the woman’s personal hygiene habits were poor to none), and then to the fruit. Dr. Soper knew that freezing does not kill germs, only high heat as with cooking. Mary’s present whereabouts were unknown. But Dr. Soper had a name and description, and was determined to locate her. His first stop was at Mrs. Stricker’s, where he was given a list of seven families for whom Mary had worked.

Dr. Robert Koch, a German bacteriologist, had proven that specific germs cause specific diseases and that germs were contagious. At the time his theory was not universally accepted; the celebrated Dr. Elizabeth Blackwell (in 1849 she was the first woman to receive a medical degree in the United States) believed that disease was caused by immoral behavior and not a chance encounter with germs. His laboratory methods, known as Koch’s postulates, are still used today. In 1902 he published a paper on the subject of healthy typhoid carriers – those who had recovered from the disease but could still transmit it. Three years later Dr. Koch won the Nobel Prize in Physiology or Medicine.

As of 1906 no healthy carrier had yet been discovered in America. Dr. Soper knew whoever did would become famous. He interviewed the families on the agency’s list and found that, in a five period with one exception, each household experienced an outbreak of typhoid fever. When nine members of one household were stricken and her employer, J. Coleman Drayton, was left alone to care for the sick, Mary pitched in to work side by side with him. So grateful was he for her assistance Mr. Drayton paid Mary a fifty dollar bonus. Dr. Soper learned of an active contagion in Mr. Walter Browne's residence at 688 Park Avenue, and discovered Mary was the cook. Two of the household's servants were hospitalized and Effie, the 25 year old daughter, had died. When Dr. Soper approached Mary about her possible role in spreading typhoid, she adamantly rejected his request for urine, stool and blood samples, chasing him from the kitchen with a carving fork. Through further investigation Dr. Soper found out Mary had a friend named August Breihof whom she would visit most days at his rooming house on Third Avenue below 33rd Street when she finished her work. He arranged with Breihof to wait in his room for Mary's arrival, this time bringing a colleague, Dr. Bert Hoobler, but again Mary refused to cooperate. Undaunted, Dr. Soper met with Dr. Thomas Darlington, commissioner of the New York City Department of Health, and Dr. Herman Biggs, its general medical officer. He presented the evidence about Mary in the most dire terms, and Dr. Biggs agreed to assign the case to Dr. Josephine Baker, a department inspector. She had lost her father to typhoid when she was sixteen. As a result she declined a scholarship to Vassar College and attended the Women's Medical College of the New York Infirmary, graduating in 1898. Dr. Baker went to interview Mary.  Dr. Baker stated "by that time Mary was convinced that the law was only persecuting her when she had done nothing wrong." A few days later, Dr. Baker arrived at Mary's workplace with several police officers, who took her into custody to be sequestered at Willard Parker Hospital on the Lower East Side. During an encounter there, Dr. Soper told Mary he would write a book about her case and give her all the royalties. She angrily rejected his proposal and locked herself in the bathroom until he left. Mary attracted so much press attention that she became known as Typhoid Mary,and thus named in a 1908 issue of the Journal of the American Medical Association. Later, in a textbook that defined typhoid fever, she was again referred to as Typhoid Mary. She admitted to poor hygiene, saying she did not understand the purpose of hand washing because she did not pose a risk. In confinement she was forced to give stool and urine samples. Authorities suggested removing her gallbladder because they believed typhoid bacteria resided there. However, she refused as she did not believe she carried the disease. She was also unwilling to cease working as a cook. The New York City Health Inspector determined her to be a carrier. Under sections 1169 and 1170 of the Greater New York Charter, Mary was held in isolation for three years at Riverside Hospital located on North Brother Island. Eventually Eugene H. Porter, the New York State Commissioner of Health, decided that disease carriers should no longer be kept in isolation and that Mary could be freed if she agreed to stop working as a cook and take reasonable steps to prevent transmitting typhoid to others. On February 19, 1910 Mary agreed that she was "prepared to change her occupation, and would give assurance by affidavit that she would upon her release take such hygienic precautions as would protect those with whom she came in contact from infection." She was returned to the mainland and given a job as a laundress, which paid less than cooking. After a while she changed her name to Mary Brown and returned to her former occupation despite having been explicitly instructed not to. For the next few years she worked in a number of kitchens; wherever she worked there were new incidences of typhoid. Mary changed jobs frequently and Dr. Soper was unable to find her. In 1915 Mary started another major outbreak, this time at the Sloane Hospital for Women in New York City. 25 people were infected and two died. She again left, but the police were able to find and arrest her when she brought food to a friend on Long Island. Public health authorities returned her to quarantine on North Brother Island on March 27th of that year. She was still unwilling to have her gallbladder removed. In 1925 when a new resident physician, Dr. Alexandra Pravska, arrived on the island she hired Mary to work as a technician in the laboratory, washing bottles and preparing slides of specimens for the pathologists, earning fifty dollars a month and saving almost $4,800 over time. Mary spent the rest of her life in quarantine at Riverside Hospital. In 1932 she suffered a stroke and remained paralyzed for the rest of her life. Mary died of pneumonia at age 69. An autopsy found evidence of live typhoid bacteria in her gallbladder. Her body was cremated, and the ashes were buried at Saint Raymond's Cemetery in the Bronx. She had made arrangements to pay for her own funeral expenses, burial plot and headstone.

Among the infections Mary caused at least three deaths occurred, but because of her use of aliases and refusal to cooperate, the exact number is not known. Since Mary was the first healthy carrier so identified by medical science, there was no policy providing guidelines for handling the situation. Some difficulties surrounding her case stemmed from Mary's vehement denial of her possible role, as she refused to acknowledge any connection between her working as a cook and the typhoid cases. Mary always maintained that she was perfectly healthy and never had typhoid fever, so she could not be the source. Public health authorities determined that permanent quarantine was the only way to prevent Mary from causing significant future typhoid outbreaks. Today, 'Typhoid Mary' is a colloquial term used for anyone who, knowingly or not, spreads disease or some other undesirable thing. 

Other healthy typhoid carriers identified in the first quarter of the 20th century include Tony Labella, an Italian immigrant presumed to have caused over 100 cases (with five deaths), an Adirondack guide dubbed Typhoid John, suspected of infecting 36 people (with two deaths) and Alphonse Cotils, a restaurant and bakery owner. However, none  was ever involuntarily incarcerated. 

In August 2013 researchers at the Stanford University School of Medicine announced they were making breakthroughs in understanding the exact science behind asymptomatic carriers such as Mary. The bacteria that cause typhoid may hide in macrophages, a type of immune cell. 

​​​​Typhoid Mary

Heinrich Hermann Robert Koch

"I have been in fact a peep show for everybody."

Mary Mallon

September 23, 1869 - November 11, 1938

Mary's cottage

The remains of Riverside Hospital on North Brother Island in 2006. Thirteen acres in size, the island is located midway of the East River between Queens and the Bronx. In 1885 the hospital was relocated here from Blackwell's (now Roosevelt) Island and served as a treatment and quarantine center for measles, smallpox, tuberculosis, typhus and typhoid fever.  The now abandoned location has been designated a bird nesting sanctuary by the New York City Department of Parks and Recreation.

Location: Division 15, Row 19, Grave 55

For all you want to know about Mary Mallon you need to read

Terrible Typhoid Mary: A True Story About The Deadliest Cook In America  (2015) by Susan Campbell Bartoletti.

"The cook was virtually a living culture tube."

George A. Soper

Elizabeth Blackwell

North Brother Island​ was 'a ramshackle Alcatraz' according to Anthony Bourdain in his book   Typhoid Mary: An Urban Historical  (2001)

Dr. Josephine Baker

No, she did not go on to star at the Folies Bergère.

Bacteriologist Emma Goldberg Sherman (left) with Mary circa 1931