Typhoid Mary

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Podcast Transcript

In 1906, George Soper, a freelance sanitary engineer, was hired to investigate several outbreaks of typhoid fever in wealthy New York households. 

The reason why these outbreaks were mysterious is that typhoid fever usually only occurred in places with unsanitary conditions.

What Soper discovered radically changed our knowledge of infectious diseases and how they spread. 

Learn more about Typhoid Mary and how she was discovered on this episode of Everything Everywhere Daily.


Typhoid fever is a bacterial infection caused by the Typhi variant of the bacterium Salmonella enterica. It is a highly contagious disease that is transmitted through contaminated food and water or through direct contact with an infected person. 

Symptoms of typhoid fever can include high fever, headache, abdominal pain, diarrhea, and a rash of flat, rose-colored spots. In severe cases, complications such as intestinal bleeding, pneumonia, or meningitis can occur.

We don’t hear much about typhoid fever anymore, which is a good thing. Because it is spread through bacterial contamination, improved sanitation, water chlorination, and food handling have dramatically slashed cases over the last 100 years.

While typhoid fever hasn’t been eradicated, it mostly only occurs in developing countries with poor water treatment, and the disease can be treated with antibiotics if caught in time. 

This, however, was not the case at the start of the 20th century. Typhoid fever was a disease that affected and killed millions. Such notable people as President William Henry Harrison, Wilber Wright, and Prince Albert all died from typhoid fever. 

Typhoid fever had been around for ages. The Plague of Athens, which occurred in 430 BC, was believed to have been a case of typhoid fever. 

In the late 19th century, the bacteria which caused typhoid fever had been identified by the German pathologist Karl Eberth, and it was confirmed four years later by the German microbiologist Georg Gaffky.

So in the first decade of the 20th century, typhoid fever was definitely still a thing, but they at least knew where it came from and had an idea of what caused it. It was spread mostly through food and water, usually in unsanitary conditions. 

In August 1906, a wealthy New Yorker by the name of Charles Henry Warren rented a house in Oyster Bay, Long Island, where his family could spend time in the summer. 

In a one-week span between August 27 and September 3, six of the eleven people in the family came down with typhoid fever. 

The doctors in Oyster Bay found it perplexing because this disease almost never appeared in the well-to-do community of Oyster Bay. 

The landlord from whom Charles Warren rented the home was concerned that if the property had a reputation for harboring typhoid fever, he would be unable to rent the property.

They took water samples from all over the house and could find nothing. 

Eventually, they hired the sanitation engineer George Soper, to investigate the matter. 

Soper knew that the case in Oyster Bay wasn’t the only case of typhoid fever that had struck wealthy New York families. There had been several cases that had popped up over the last several years. 

Soper found a link between the outbreaks in many of the upscale New York homes. They had all hired an Irish woman as a cook who fit a similar description in every house. 

However, Soper was unable to find the woman because she seldom worked in one place for an extended period and would often leave the home after an outbreak began. 

The big break in the case occurred in January 1907. The household of Walter Bowen, who lived at an upscale Park Avenue address, had an outbreak of typhoid fever. Several members of his household staff caught it, and his daughter died. 

When Soper investigated the Bowen household, he found the woman he had been looking for. A 38-year-old Irish immigrant by the name of Marry Mallon. 

She was the link between all of the typhoid fever cases. 

Mallon was born in 1869 in County Tyrone. At the age of 15, she migrated to New York  She initially took jobs as a maid, but eventually moved into cooking because the money was better. 

An investigation into her work history between 1900 and 1907, found that she worked as a cook for eight families in New York, seven of which came down with typhoid fever.

Soper first attempted to notify Mallon about his discovery while she was working at the Bowen household. It was a very touchy conversation, because how exactly do you tell someone that they were responsible for passing a deadly disease to dozens of people? 

Despite trying to be diplomatic, Mary had a very violent reaction to being told the news. She refused to believe that she was the cause of this, as she had never been sick, and she claimed, not incorrectly, that there were typhoid cases all over. 

When she was asked to provide urine and stool samples, she threatened Soper with a carving fork. 

He arranged another meeting with her at her boyfriend’s apartment, and once again, she refused to provide samples that they could test for the bacteria.

Given his concern about Mary further spreading the disease, he got the New York City Department of Health involved and told them about the results of his investigation. 

The Department of Health arrested Mary Mallon as being a threat to public health and safety. She was forcibly taken away in an ambulance by five police officers who had to physically restrain her. 

She was taken to a hospital, where she was forced to provide stool samples. What they found was an incredible number of typhoid fever bacteria.

Mary Mallon was somehow carrying the bacteria but not suffering from the disease.

Once the test results came back, she began to accept her condition and cooperated with the researchers. One of the key things she mentioned was that she almost never washed her hands. 

Here I should mention what some of you are probably thinking. This sounds very familiar to the episode I did on Dr. Ignaz Semmelweis who encountered something similar almost 60 years earlier in Vienna. 

Despite the mounting evidence, the germ theory of disease still wasn’t universally believed at this point. 

In March 1907, she was sentenced to involuntary quarantine at Riverside Hospital on North Brother Island in the East River, located between the Bronx and upper Manhattan. Riverside Hospital was built as a quarantine hospital. 

It wasn’t prison, but it also wasn’t not prison, if you know what I mean.

Soper wrote an article on his findings for the Journal of the American Medical Association about Mary 

That article was picked up by local newspapers and tabloids who, coined the phrase, Typhoid Mary.

The forced quarantine of Mary was controversial at the time. Not all doctors agreed that she should be isolated. Rather, they felt if she just learned to take certain precautions, her condition could be treated. 

Mary herself never believed that she was a carrier. She arranged for an independent analysis of her samples which came back negative, as did a quarter of the samples taken while she was in quarantine. 


Eventually, after three years in isolation, in February 1910, she signed an affidavit that said she would stop being a cook and would take other precautions and was released. 

No one was sure where she got the money to pay for her legal fees. One persistent rumor was that the media mogul William Randolph Hearst paid for it. 

After being released, she took a job cleaning clothes instead of cooking which paid significantly less than what she was making before. 

Eventually, desperate for money and on the edge of poverty, Mary returned to the world of food preparation. 


She used fake names to avoid detection. She couldn’t work for upscale homes anymore, so instead, she began to work in the commercial food industry. She took jobs cooking at hotels and restaurants. 

Everywhere she worked, there were outbreaks of typhoid fever. 

Soper tried to track her down again but had a difficult time because she changed jobs frequently and used different aliases. 

In 1915, there was an outbreak of typhoid fever at the Sloane Hospital for Women. When Soper was called in to investigate the outbreak, all the signs pointed back to Mary Mallon. 

This time the police managed to find Mary, who was traveling to Long Island to deliver food to a friend. 

She was returned to North Brother Island, but this time her stay was quite different. She ended up spending the next 23 years on the island. 

She was given a small cottage on the island and was given a job as a laboratory assistant. 

Mary suffered from a stroke in 1932 and died in 1938 at the age of 69. Twenty-six years of her life were spent in isolation. 

Nine people attended her funeral. 

In hindsight, we can see that Marry Mallon was the first person identified as what we could now call an asymptomatic carrier, also known as a super spreader. 

The bacteria, it was believed, lived and grew in her infected gallbladder. She may have had it her entire life as her mother had typhoid fever when she was pregnant. However, for whatever reason, she never suffered from the symptoms of typhoid fever. 

The number of cases of typhoid fever and the number of deaths she was responsible for varies widely. On the low end, there could have been just three deaths, and on the high end, perhaps as many as fifty. 

After Mary was put into isolation, typhoid fever cases would still periodically appear. During her isolation, another 400 asymptomatic carriers of typhoid fever were found, but none of them were put into isolation like Mary Mallon. 

One of the lingering mysteries was how she was able to spread the disease when the high temperatures from cooking would kill the bacteria. The answer might have lied in one of her signature dishes, peach ice cream. The desert was never cooked, and it could have been the vehicle of transmission. 

The case of Mary Mallon has been debated by ethicists for over a century. She had no idea that she was a carrier for the disease, and in fact, the very idea of an asymptomatic carrier didn’t even exist before she was arrested. 

By almost any measure, she lacked malice and would be considered innocent if the case had come to court. 

However, after her release, she knew very well what she was doing and what could happen, and the disease spread yet again.  

The case of Marry Mallon helped researchers better understand just how diseases were spread, and helped introduce the concept of super spreaders. 

Today, most people have heard the term “Typhoid Mary” and its use to describe someone who unwittingly causes harm, but few know the story of the actual woman who spread the disease and how she was discovered.