Who Was Typhoid Mary? Harvard Professor Martin Kulldorff's Disease Tweet Raises Eyebrows

Discussion around the historical figure Mary Mallon—also known as Typhoid Mary—has picked up on Twitter after a Harvard professor published a controversial tweet.

On Tuesday, Martin Kulldorff, a Harvard Medical School professor who specializes in disease surveillance and outbreaks, expressed concern about people being blamed for infecting others.

He tweeted: "For thousands of years, disease pathogens have spread from person to person. Never before have carriers been blamed for infecting the next sick person. That is a very dangerous ideology."

As of Wednesday morning the tweet had gained thousands of likes and retweets and over 5,000 replies. Many Twitter users criticized Kulldorff's claim that individuals had never before been blamed for spreading disease and pointed to the case of Typhoid Mary as an example.

In a statement to Newsweek about his tweet, Kulldorff said: "The second sentence is incorrect. Blaming disease carriers was wrong in the past. It is disturbing that such blame and shame now comes from public health officials, scientists and politicians. It is a very dangerous ideology."

Who was Typhoid Mary?

Mary Mallon was an Irish-born cook who lived in New York after immigrating to the U.S. in the 1880s. In 1906, she was employed as a cook for a New York banker and worked at the banker's residence.

At some point she developed the disease typhoid fever, which is caused by the Salmonella typhi bacteria that can spread via contaminated food or water or by close contact with an infected person.

The disease causes symptoms such as high fever, headache, and stomach pain. While most people recover, a small number of people who catch it die of complications.

Mallon, along with other people in the house, fell ill with the disease and civil engineer George Soper began investigating the cases.

Soper found that Mallon had been connected with other residential outbreaks as well, and suspected her of being a carrier of the disease in 1907.

Soper enlisted the help of local authorities in order to force Mallon to supply stool samples for testing, which she had refused to do initially. Testing found that typhoid bacilli were present in the samples, and Mallon was sent to New York's North Brother Island to live in isolation.

Not everyone considered this fair. In the journal Science, W.P. Mason of the Rensselaer Polytechnic Institute wrote in 1909 that Mallon was "only one among many such 'carriers' and it is scarcely justice to place upon her alone the burden that should be shared by her entire class."

According to a study published in the Annals of Gastroenterology in 2013, during this period of confinement "no one ever attempted to explain to Mary the significance of being a 'carrier'."

Mary, who had fought against her imprisonment, was released in 1910 on the condition that she no longer worked as a cook. She was given the nickname Typhoid Mary in the media.

However, in 1915 Mallon was found to be working in the kitchens of Sloane Maternity Hospital where an outbreak of typhoid had killed two people and made 25 ill.

After that outbreak, Mallon was sent back to North Brother Island where she spent the rest of her life until her death in 1938. Other healthy typhoid carriers were identified over time but only Mary was known to be imprisoned. It is unknown exactly how many illnesses she was connected with in total.

This article has been updated with comment from Martin Kulldorff.