Food, Sex and Salmonella. David Waltner-Toews

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3 SALMONELLA READING IN TURKEY

FOODBORNE INFECTIONS, FOCUSING ON SALMONELLA

      TO SOMEONE not well versed in the literature on food poisoning, the title of this chapter might sound like a headline in a supermarket tabloid about a literate fish discovered in Istanbul. In fact, the report that carried this title described an outbreak of gastrointestinal disease among hospital food-service employees related to infection with a particular strain of the bacteria Salmonella first recognized in Reading, England, and therefore named after that place. Salmonella are often named after the places where they were first discovered. If the Salmonella were to have their own family picnic, there would be some 2,500 of them, from all over the world. There are Salmonella named after Aberdeen and Adelaide, Caracas and Dublin, all the way down the alphabet to Zanzibar. These names could result in mind-bending medical headlines, involving, say, Salmonella uganda invading New York. Microbiologists have recently tried to remedy this problem by giving all the Salmonella that attack the gut a middle name, enterica. This system may please the classifiers, but it doesn’t do much for those who just want to give their gut problems a proper name. In this book, I have stuck with the old names, just because they require fewer words.

      If we take a global view of our existence on this planet—that is, that we are all part of the living, breathing organism that British scientist James Lovelock has called Gaia—then the bacteria, parasites, and even natural toxins that make us sick are as much at home here as we are. They are not here to make us sick, any more than we are here to destroy the rain forests. If evolutionary microbiologist Lynn Margulis is correct, then people are entirely composed of various kinds of bacteria, and each of us is a synergistic colony of microbes, a cross between priest-archeologist Teilhard de Chardin’s grandiose vision of the universe becoming God and an amazing, lumbering grade-B horror movie attempt of the universe to understand itself. “What a piece of work is man!” said Shakespeare. Indeed.

      The sicknesses we suffer are a side effect of an imbalance in human-microbial relations, some distortion in our collective ecosystem, resulting in the migration of disease-causing microbes from their natural homes into our food, and from there into our bodies. More often than not, the ecosystem distortion or cause of the bacterial migration is human in origin. Perhaps the easiest way to explore foodborne infections as a complex social-ecological issue is to look closely at the emergence and behavior of Salmonella epidemics over the past few decades.

      On June 24, 1984, a seventy-one-year-old lady went to a family picnic in Moncton, New Brunswick. Little did she know, when she ate her morsel of cheese, that she was to be part of a great Canadian historical event, celebrated in bacterial circles and rued in milk producers’ circles for many years to come. On June 27, this modest, grandmotherly woman came down with nausea and diarrhea. Although some folks have been known to react in similar fashion to family picnics, this woman did not think family events were quite that bad. On June 28, she started vomiting; by June 30, things were getting worse, and she ended up in the hospital, from which she emerged shaken but alive on July 5.

      That same day, the cheese manufacturer, in Prince Edward Island, issued a national recall of its products, which were distributed across Canada under various brand names. What the woman in Moncton did not know was that she was near the tail end of a six-month epidemic of salmonellosis that attacked more than two thousand people in the Maritimes and Ontario. The investigation of this epidemic, the largest of its kind in Canada, had progressed more slowly than it should have for various reasons. Not all the investigators saw the value of sound epidemiologic methods and did not always include a comparison, or control group, in their investigations. Cheese was not always considered a real food by those who got sick; they thought of it as a snack and thus did not include it in their food history questionnaire. The cheese involved was distributed to most Canadian provinces under eighteen brand names, making it difficult to trace. Finally, the number of bacteria in the cheese was very low. One Canadian researcher estimated, based on a series of case studies, that people in this epidemic got sick by eating fewer than half a dozen of these microscopic bacteria.

      The organism involved in this epidemic, a strain of Salmonella typhimurium, was traced back to the factory where the cheese was made. There, it turned out, one of the workers decided to turn off some valves manually, even though an electronically controlled flow-diversion valve was in place. As a result, raw milk that was supposed to go to the pasteurizer ended up in the cheese vat, and 2,700 people got sick. The milk with the Salmonella in it was traced to one teat on one cow on one farm. She was a good producer, but she had chronic mastitis, not caused by Salmonella, although she was shedding it.

      Most of the agents that cause food poisoning have a natural home—that is, they have evolved a niche for themselves where, like most of us, they carry out their recycling and respiratory functions with minimal trauma to their immediate neighbors. Over the years, a high proportion of outbreaks of foodborne disease in Canada and the United States has been traced to chicken, turkey, pork, and beef. Other Salmonella prefer pigeons, gulls, and people.

      As in any respectable family, there are a few black sheep and troublemakers that will stir up a good gut incident no matter where they are. However, in its natural home setting, Salmonella organisms, like most of the agents that cause foodborne disease, often live like good quiet farmers in the hinterlands of their chosen animal hosts. The Maritime cow with the bacteria dripping from her teat is typical.

      That year, 1984, George Orwell’s year of doom, was a bad year for salmonellosis in Canada. In September 1984, for instance, the Pope helicoptered in to visit the Jesuit mission of Sainte-Marie among the Hurons near Midland, Ontario. Of the more than sixteen hundred police officers who provided security, five hundred ate the roast beef boxed lunch offered by volunteers. Within the next twenty-four hours, as they headed home, just about every one of those police officers got sick. Newspaper reports describe police sick with severe diarrhea and vomiting on buses and motorcycles, finding bathrooms where they could, running from squad cars into the woods. In the weeks that followed, twenty-seven (over 6 percent) of the infected officers developed reactive (secondary) arthritis—pain and swelling in many of their joints. Some of them ended up with permanent joint damage. This painful arthritis, which is sometimes associated with eye and urinary tract inflammation, is a known consequence of infections with foodborne organisms such as Salmonella, Campylobacter, and Yersinia. Reactive arthritis used to be called Reiter’s syndrome, after the physician who discovered it in 1916. Unfortunately, Dr. Reiter later went on to a less-than-glorious career doing experiments in the Nazi death camps—hence the new name for the disease.

      The 1984 outbreaks in Canada were a sign of things СКАЧАТЬ