Food, Sex and Salmonella. David Waltner-Toews
I guessed that there had been no eggs in what I had eaten, or I would not have survived the night.
I could likely sue the restaurant owner, but he’s an acquaintance, so I haven’t even told him. Which is probably irresponsible of me. Instead, I have my students prepare public dissemination projects and hammer into them the public part of public health. And I write books like this one.
At least one kind of food intoxication mimics an allergic reaction. Sometimes, in scombroid fish such as tuna and in some cheeses, bacteria may partly digest the food (some might call it spoilage, but I am trying not to be judgmental). When eaten in large amounts, such spoiled foods cause symptoms that may be confused with those of true allergies: a burning in the mouth and throat, flushing, and dizziness.
In early March of 1981, a young, organized British Columbia woman bought two cases of canned tuna. She opened a can from the first case and ate the contents, despite their strange, bitter taste, on March 15. About half an hour later, she felt nauseated, her throat was swelling, and she felt hot; she also developed what appeared to be a rash on her chest and back. On March 22, probably thinking about fiscal responsibility and the large investment she had just made in tuna, she tried again, with the same results. Almost exactly nine years later, three people in downtown Toronto tried out a local luncheon special of mahimahi fish. Within the next hour, all three felt as if they had a sudden sunburn. Peppery taste, headache, dizziness, diarrhea, and flushing are recognized symptoms of food allergies.
At one time, scombroid fish poisoning was thought to be a kind of allergy. Now we know that it is neither an allergy nor restricted to scombroid fish such as tuna, mackerel, and other dark-fleshed fish, like mahimahi. Scombroid “fish” poisoning has also been reported from eating Swiss cheese. Some bacteria will digest foods containing the amino acid histidine, such as fish that have not been cleaned and chilled quickly enough. The product of the bacteria’s labor is histamine, the same compound made by our own bodies during an allergic reaction—hence the similarities in clinical picture. The big difference, however, is that our bodies learn from a food allergy. One encounter, however benign, enhances the seriousness of the next. Scombroid toxicity is more like a predictable aunt, with unchanged irritability from visit to visit.
In both neurological and allergic-type reactions, ordinary citizens might ascribe their state to a stimulating dinner companion, were it not followed so inconveniently by more serious gastrointestinal or neurological complications.
Foodborne illnesses may also result from food intolerances, in which case your body does not have the enzymes necessary to digest certain parts of certain foods. Milk intolerance is a common problem among some ethnic groups, which results in frothy diarrhea and cramps. Many of us can recall stories of poor villagers in some developing country using powdered milk to whitewash their houses. One might view this use as a form of ingratitude in the face of our obvious generosity, but such generosity is not much different from their sending us skewered cockroaches to solve our food problems. Another food intolerance, this one found in many people of Mediterranean origin, is called favism. These people can develop an acute hemolytic anemia if they eat fava beans.
The large intestine is mostly a place where fluids and electrolytes get sucked back into your body. Being less acidic than other parts of your gut, the large intestine is generally hospitable to bacteria, many of which normally make their home there and don’t cause illness. In fact, one might suggest that the only ecological and evolutionary justification for the human race is to serve as a living area for large numbers of anaerobic (air-intolerant) bacteria. This perception is not as heady as thinking of ourselves as the brains of evolution, but in ecologically recessionary times, when millions of species are going extinct for lack of a working niche, it is at least a job. The total number of bacteria excreted by an adult each day ranges from a hundred billion to a hundred trillion.
If pathogenic agents do manage to get a foothold in these nether regions, we feel lower abdominal cramps and can develop bloody diarrhea. Red blood in the feces is a sign that the destruction must be quite low down, because blood entering the intestines higher up turns black through partial digestion.
Finally, high-fiber foods such as bran will draw water into the large intestine and smuggle it away to the great outdoors in what is called an osmotic diarrhea.
The foregoing are the acute effects of foodborne diseases. These diseases may also have long-term effects, sometimes called sequelae. Reactive arthritis develops in more than 6 percent of people who get salmonellosis and in probably 1 percent of those with Campylobacter infection. Campylobacter infections can be followed by Guillain-Barré syndrome, in which people develop burning sensations and paralysis; 15 percent of them die. There is also some evidence that foodborne infections may contribute to plaques in blood vessels and hence to cardiovascular disease. Diseases caused by E. coli O157:H7 (so-called hamburger disease) can lead to chronic kidney failure or chronic bowel diseases. Some kinds of fish and shellfish poisonings result in chronic neurological and memory problems (that’s my excuse for forgetting things).
So, you have survived the journey; to paraphrase an ancient Persian saying, the fine wine of France has been transformed by the human body into urine, and the succulent cabbage rolls of Kiev have been transformed into fertilizer. Millions of bacteria have died. Millions more have been born. Whole civilizations have come and gone in the bowels of your body. Truly, a Wagnerian chorus could not match the richness of this drama.
FOR
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