GASTROINTESTINAL DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 255

SPECIFIC CAUSES OF DIARRHEA
Staphylococcal Enteritis
Staphylococcal enteritis is a type of acute gastroenteritis caused by a toxin produced by
staphylococci. These bacteria are present on the hands of about half the population, and
contamination of food during preparation is common. Any food may harbor the organ-
isms, but salads made with mayonnaise, sweets such as custards and cream pies, meat, and
milk are the most common sources. The staphylococcal toxin is produced when contamin-
ated food is allowed to stand unrefrigerated for several hours, which allows the organisms
to multiply and produce toxin. Subsequent reheating—even boiling—does not destroy the
toxin or prevent illness. To prevent contamination and growth of the organism, food must
be consumed or refrigerated immediately after it is prepared. (Food contamination with
otherorganismsthathaveaveryshortincubationperiodcanproduceanidenticaldisorder.)
The onset of cramps and diarrhea, with or without nausea and vomiting, occurs one
to six hours—an average of three hours—after contaminated food is ingested and is fre-
quently abrupt. The diarrhea lasts until the gastrointestinal tract is emptied, rarely more
than five to six hours. Most of the individuals who have eaten the contaminated food de-
velopthedisease,whichestablishesthediagnosis.Antibioticsarenoteffective;theydonot
neutralize the toxin. Antidiarrheal and antiemetic agents may help.
Giardiasis
Foryearsfranticalarmsabouttheperilsof Giardiasis havearousedexaggeratedconcern
about this infestation. Governmental agencies, particularly the U.S. Park Service and the
U.S. Forest Service, have filtered hundreds of gallons of water from wilderness streams,
found one or two organisms (far less than enough to be infective), and erected garish signs
proclaiming the water “hazardous.”
Giardiasis is not a new problem. Giardia have always been present in wilderness
streamsandinthewatersuppliesformostcities.Theyoftenhavenotbeendetectedbecause
they are not isolated by routine bacterial cultures. This protozoal parasite is found all over
the world. Many animals harbor and excrete the organisms, resulting in contamination of
wilderness streams, but the organism has been found in the municipal water supplies of a
number of large U.S. cities, as well as in cities as diverse as St. Petersburg in Russia and
Kathmandu in Nepal.
In humans, the noninvasive parasites live in the upper intestinal tract, where they form
numerous cysts that are passed in the stool. The cysts do not produce active disease but are
resistant to disinfectants and other agents in their environment and do transmit the infesta-
tion. Fecal contamination of water is the most common route of transmittal. Less common,
but significant, is direct passage of cysts or organisms from stool to the hands of a food
preparer and to the food itself.