Today, at a time when we are in the grip of a major pandemic, we’re going to look at the impact of a name change on a significant outbreak of typhoid in the eastern United States in the early 1900s.

Why did Mary Mallon, born in Tyrone in 1869, and who emigrated to the USA in the 1880s, change her name to Mary Brown in 1915? And why did she lay down a marker in medical history?

Perhaps if we call her by her notorious nickname all will become clear. She was better known as Typhoid Mary and was the first asymptomatic carrier of the potentially deadly disease. Put simply, what that means is that Mary Mallon was a carrier of the pathogen associated with typhoid fever who did not exhibit symptoms of the disease herself. Neither, as far as is known, did she ever suffer from typhoid fever, although she managed to pass on typhus to dozens of others.

Mary Mallon was a cook, which was part of the problem. Appropriately enough she was born in Cookstown, though it’s unlikely that the members of the families she infected, would have appreciated the irony. She held a variety of positions in the kitchens of wealthy families in upstate New York and Long Island in the early 1900s. She admitted when she was finally caught that she wasn’t overly fond of washing her hands while she prepared food, she just didn’t see the point. When members of her employers’ families began to drop like flies, with salmonella or typhoid symptoms, she was generous in offering assistance in nursing them. Everybody might have been better off if she’d stayed in the kitchen, or even better, the laundry.

She must have had some sense that either she was the source of the problem, or that her cooking wasn’t very good, because she spent much of her working life giving notice and moving on, leaving a trail of infection behind her.

Enter Dr George Soper, medical Nemesis. He was hired by one of the infected families to trace the origin of the typhus. He became aware of an unusual upsurge in the disease in well-to-do households around greater New York. Now typhus then, as now, was a disease of poverty. People living in poor and unsanitary conditions were supposed to succumb to the disease, not the well off. What was the point in being rich if you could still contract typhoid fever in the 1900s? Soper quickly identified Mary Mallon as the common denominator and Mallon was forced, much against her will, to give up stool and urine samples (apologies if you’re eating at the moment). These established that she had a gall bladder which was a balmy island home to millions of happy microbes of typhoid salmonella, delighted at having found an understanding host prepared to allow them out into the wider world for an occasional adventure.

Mary Mallon was labelled public health Enemy Number One and placed in isolation in a cottage in the Bronx in 1907. It was suggested that her gallbladder—still a much sought after retirement home for bacilli—should be removed. Mallon loudly declined.  Three years later she was released, on condition that she would only work in the badly paid vocation of laundress and that she would never so much as boil and egg again for anyone other than herself.

You’ve probably already worked out what happened next. Mary Mallon, unhappy with the company of soap suds and steam, changed her name to Mary Brown and sought employment, once again, as a cook. With similar results. She left an entirely new trail of typhoid victims in her wake.  Because she was a serial employee who tended to abandon jobs rather than serving out notice and leaving a forwarding address, it took the New York public health authorities five years to catch up with her. When they did there was no going back this time. She was quarantined for the rest of her life on an island in New York’s East river. When she died, in 1938,  after a total of almost three decades in isolation, her body was cremated.

Because Mary Mallon (Brown) was not the most co-operative of individuals—she adhered to the Ulster axiom ‘whatever you say, say nothing’—no one knows exactly how many deaths she caused with her extra-curricular culinary skills. The official number is three, although some contemporaries, without producing any evidence, claimed it was as high as fifty. However, she was certainly not responsible for the death of hundreds, so that’s fake history. Do enjoy your evening meal.