Mary Mallon was proud of her craft.
At the turn of the 20th century, Mary was in demand by wealthy Manhattan families for her skills as a cook. One day, a city official, George Soper, knocked on the door of the fancy brownstone where Mary was employed.
He had a few simple requests to make of Mary. Could he please have a sample of her blood, her urine, and her feces? Oh, and, this little question: Did she regularly wash her hands after going to the bathroom?
That was one question too many for Mary. She grabbed a carving fork, swore, and lunged for the man, who wisely exited the home.
And you thought the Target and Walmart anti-maskers overreacted.
Four months prior to his abrupt ouster from Mary’s place of employment, Sober, a New York City sanitary engineer, was asked to investigate an epidemic that would eventually sicken thousands of New Yorkers. Soper began by interviewing a particularly hard-hit family in their Long Island summer home.
Just weeks into their vacation, the family’s nine-year-old daughter fell seriously ill. All told, six out of eleven members of the household, both family and staff, fell sick.
Soper interviewed the family and discovered that the cook – Mary Mallon – had returned to New York City soon after, apparently healthy as a horse.
New York was in the midst of a typhoid fever epidemic. Typhoid fever is caused by Salmonella bacteria and in 1907, was fatal in ten percent of infections. Immunization against typhoid fever was four years away and an effective antibiotic was almost forty years away. Carried in feces and usually found in areas with poor sanitation, typhoid fever’s appearance in wealthy areas was a mystery.
But Soper was onto to something. He questioned the family about the menus prepared by Mary, and discovered that shortly before illness broke out, Mary had served her Sunday specialty: homemade ice cream and fresh peaches. Compared to her hot cooked meals, Soper concluded that “no better way could be found for a cook to cleanse her hands of microbes and infect a family.”
Soper searched New York for four months, looking for Mary Mallon. In his search, he identified eight families for whom Mary had cooked, going back several years. Seven families had outbreaks, with twenty-two sick and several deaths.
In a few years, newspapers would dub Mary Mallon “Typhoid Mary”.
It took police officers, an ambulance, a female doctor, and a foot-chase over the backyard fence to finally bring Mary in for testing. Mary tried her best to resist, holding her stool sample as long as possible. Ultimately, nature called, and Mary tested positive for high levels of Salmonella. Completely and absolutely healthy, Mary denied ever being sick with Typhoid.
She was quarantined on a hospital island for two years, producing typhoid-positive samples the entire time.
She sued the health department, lost, but was finally freed from the hospital in 1910. Mary agreed to check in regularly with the health department, and importantly, Mary agreed never to work as a cook again.
After a while, Mary stopped checking in and, feeling fit as a fiddle, returned to cooking: for a hotel, a Broadway restaurant, a spa, and a boarding house.
In 1915, typhoid fever broke out in a New York maternity hospital. At least twenty-five nurses, doctors, and staff were infected, and two died. The cook was a woman named “Mary Brown” who, surprise, surprise, turned out to be Mary Mallon.
Mary was again transferred to the quarantine island, where she lived until her death in 1932, adamant that she had never been sick with typhoid.
Mary was the first known case of a healthy carrier in the United States. She was traced to the infection of at least 122 people, including five deaths. In 1907 alone, 3,000 New Yorkers were infected with typhoid, most likely due to Mary.
Mary’s legacy as an asymptomatic carrier of a deadly disease has informed every widespread disease outbreak since.
Forty percent of Covid-19 infections have no symptoms. A Boston homeless shelter had 147 infected residents, but 88 percent of them had no symptoms. A Tyson poultry plant in Arkansas had 481 infections, and ninety-five percent were asymptomatic. Prisons across multiple states found 96 percent of infected people were asymptomatic.
A large number of infected but asymptomatic people is a good thing, of course, but that’s not the whole story. Apparently, seemingly healthy people are just as capable of carrying large viral loads and infecting others as are people with symptoms.
Compounding the situation are the “super-spreaders”. Super-spreader events, where a single person infects a large number of people, are widely documented.
The World Health Organization initially did not recommend population-level face masking, but changed their recommendation in June 2020 when the extent of transmission by asymptomatic individuals was confirmed.
It wasn’t a flip-flop. With new data, science changes its mind.
A poor immigrant with little education, Mary can possibly be excused for not understanding the nuances of being an asymptomatic carrier.
But we should know better. When you wear a mask in public spaces, you are probably protecting yourself a bit. But mostly, you’re protecting everyone else in case you are one of the asymptomatic carriers.
Love your neighbor as yourself.

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And as You speak
A hundred billion creatures catch Your breath
Evolving in pursuit of what You said
If it all reveals Your nature so will I
(Hillsong United “So Will I“)
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