Infectious diseases have a long history. The first epidemics were probably caused by the variola virus that causes smallpox. The disease commonly spreads through skin-to-skin contact or contact with bodily fluids, but it can also be spread through the air. Smallpox first appeared around 10,000 B.C. at the time of the first agricultural settlements in northeastern Africa. Egyptian mummies that date back to about 1500 B.C. show evidence of skin lesions typical of smallpox. From Egypt, the disease was probably spread by traders to Europe and India. In 430 B.C. a smallpox epidemic killed over 30,000 people in Athens, reducing the population by some 20%. Smallpox was also the first disease for which a vaccine was developed. One of the most famous stories in medical history is that of Edward Jenner’s capitalization on his observation that milkmaids who contracted cowpox became immune to smallpox. In 1796 he injected a young boy with puss from a milk maid’s cowpox lesions and then went on to inoculate the boy with material from a smallpox lesion. The boy did not contract smallpox and the concept of vaccination, the term deriving from the Latin for cow, was born.
Today we worry about the SARS-CoV-2 virus, but viruses are not the only microbes that can spread disease. Bacteria are adept at that as well. That brings us to the story of Mary Mallon. Mary made the most delicious ice cream, but the problem was that it could kill you. That’s because Mary carried more than the ingredients needed for ice cream, she carried the Salmonella Typhi bacterium, the bacterium that causes typhoid fever. And she was well-deserving of the name that was bestowed upon her, “Typhoid Mary.” Today, typhoid fever is rare in North America thanks to sanitation and the use of antibiotics to prevent its spread, but it still strikes some 12 million people in the developing world every year. Vaccinations are available and are a must for anyone traveling into areas where the disease is still found. Risk is reduced by drinking only bottled water, eating foods that have been thoroughly cooked and are still hot, and avoiding raw vegetables and fruits that cannot be peeled.Â
The typhoid bacteria, which live only in humans, can be spread through sewage or through food that has been handled by someone shedding bacteria. A high fever can ensue and even death if antibiotics are not available. Before widespread water purification, epidemics of typhoid fever were common. But nobody really knew how the disease was transmitted. At least not until 1906 when ten people in the same household in Long Island, New York, suddenly came down with typhoid fever. Health authorities sent Dr. George Soper to investigate. Soper had experience with bacteria and knew that Salmonella typhi had been cultured from the stool of typhoid patients as early as 1884. He suspected that the disease could be passed from person to person and asked if there had been any visitors to the house. Yes, he was told, a new Irish cook had recently been hired but was no longer there.Â
Dr. Soper then traced Mary Mallon through an employment agency and discovered that there had been at least one case of typhoid everywhere she had worked. Finally, he caught up with her in a Park Avenue apartment where the owner’s daughter had already died of typhoid and two servants suffered from it. When he explained to her that she was spreading disease, Mary attacked him with a clever. The police were called and Mary was taken away screaming, kicking, and biting. Health officials found live bacteria in her stool, demonstrating for the first time that typhoid fever could be passed by people who carried the bacteria but were themselves immune to the disease.Â
Mary was forcibly isolated in Riverside Hospital for three years and was finally released when she agreed to never cook for others and check in every three months. She then disappeared, only to resurface five years later at another New York hospital where she had been hired as, (guess what?), a cook! Twenty-five nurses in the hospital were ill with typhoid. Mary was returned to Riverside Hospital where she was confined for the next twenty-three years, living in a cottage specially built for her. She finally died of a stroke with her funeral being attended by only nine people because of the fear of catching typhoid fever from Typhoid Mary. Today, the Mary Mallone story resonates, as she most probably represents the first case of preventing the spread of an infectious disease by forced isolation.
