John D. Wilson, M.D.
1200 Hilyard St., Suite S-560
Eugene, Oregon 97401 USA
541/343-6028   fax 485-7702
www.TravelClinicOregon.com

 RISKS FROM FOOD AND DRINK
(AND TRAVELERS' DIARRHEA INFO)

the short version

1. Regarding food: if you can't cook it, boil it or peel it, then forget it. No frozen desserts, such as ice cream, sherbet or popsicles. No raw vegetables. No milk products.

2. Regarding drink: bottled drinks or disinfected water only.

3. If  you have diarrhea despite your best efforts at prevention,
   a.  take two loperamide 2 mg pills for starters, then one after each loose stool (available either with or without prescription generically or as brand name Imodium; purchase before departing) and 
   b.  you have the option to start a prescription antibiotic (see below).
   Both medications are available in our Travelers’ Diarrhea Treatment Kit available for purchase at our front desk.

the long version

Contaminated food and drink are common ways to catch several infections, most commonly giardia and hepatitis A. Other less common food and waterborne infectious disease risks include typhoid fever, other salmonella, shigella, campylobacter, amoebae, cholera, several viruses and a variety of one-celled and worm-like parasites.

WATER which has been adequately chlorinated using minimum recommended waterworks standards as practiced in the United States will give protection against waterborne diseases. However, chlorine treatment alone used by individuals for water disinfection is hard to standardize and will not reliably kill some viruses, giardia and amoebae. In areas where chlorinated tap water is not available or where hygiene and sanitation are poor, the only safe drinks are: 

1. beverages, such as tea and coffee, made with boiled water
2. canned or bottled carbonated beverages, including carbonated bottled water and soft drinks
3. beer and wine.

Where water safety is uncertain, ice and containers for drinking should also be considered contaminated; ice should not be used in beverages. If ice has been in contact with a container to be used for drinking, all surfaces should be thoroughly cleaned (preferably with soap and hot water) after the ice has been discarded. It is safer to drink directly from a can or bottle of a beverage than from a questionable container; however, the outside of the can or bottle might be contaminated. Wet cans or bottles should be dried before opening and surfaces which are in direct contact with the mouth should first be wiped clean. Some travelers are so cautious that they drink only carbonated beverages and insist upon personally opening all bottles, thus proving to themselves that the bottle has not been refilled by an unscrupulous eating establishment. Where water may be contaminated, travelers should not brush their teeth with untreated tap water.

WATER TREATMENT Boiling is the most reliable method to make water of uncertain purity safe for drinking. Water should be brought to a vigorous boil and allowed to cool at room temperature; do not add ice. For an extra margin of safety at very high altitudes where boiling temperatures are lower, boil for several minutes or use chemical disinfection. To improve the taste, add a pinch of salt to each quart or aerate by pouring the water several times from one container to another after cooling.

Chemical disinfection with iodine is an easy, reliable method of water treatment when boiling is not feasible. Two well tested methods are: 

1. tincture of iodine; our iodine water disinfection kit is provided; additional kits are available for purchase at our front desk, and 
2. tetraglycine hydroperiodide tablets (Globaline, Potable Aqua, Coghlan's, etc., available from many pharmacies and sporting goods stores). Manufacturers’ instructions should be followed.

The tincture of iodine method is preferred over the tablet method because no dissolving time is needed, greater availability throughout the world, greater stability in heat, longer shelf life and lower cost. If water is cloudy or cold, the amount of iodine preparation and/or the recommended contact time should be doubled to achieve reliable disinfection. Cloudy water should be strained through a clean cloth into a container to remove any sediment or floating matter before treatment with heat or iodine. Pregnant women should not use iodine disinfection.

There are a variety of portable filters currently on the market which, according to the manufacturers, will provide safe drinking water. Although iodine impregnated resins and the microstrainer filters will kill and/or remove many germs, very few published reports adequately evaluate the efficacy of these filters against waterborne pathogens, especially viruses. (See companion handouts F: WATER DISINFECTION or the Backpacker Magazine field trial available in our office for more information about water filters).

water disinfection with tincture of iodine

*very turbid or very cold water may also require prolonged contact time
**let stand at least 30 minutes before use, preferably several hours if possible

As a last resort, if there is no sure source of safe drinking water, tap water that is uncomfortably hot to touch (140 deg F; take a thermometer?) is usually safe. After allowing such hot water to cool to room temperature in a thoroughly cleaned container, it might be used for brushing teeth and drinking.

CHOOSING FOOD with care will help avoid illness. Any raw food may be contaminated. Particularly in areas where hygiene and sanitation are inadequate, the traveler should avoid salads, uncooked vegetables, unpasteurized milk (perhaps avoid any milk products). We advise eating only cooked food which is still very hot when served, or fruit peeled by the traveler. Undercooked and raw meat, fish and shellfish may carry various intestinal germs. We advise against frozen desserts, such as ice cream, sherbet, or popsicles.

TRAVELERS' DIARRHEA (TD) causes sudden liquid stools, nausea, bloating, a sense of urgency to have a bowel movement, perhaps mild abdominal cramps and a general ill feeling. TD usually occurs during travel or soon after returning home, is self-limited and is usually more an inconvenience rather than a serious disease. The chance that a traveler is going to come down with TD is in the range of 20 to 40 percent. The most important determinant of risk is the destination of the traveler. High risk destinations include most of Latin America, Africa, the Middle East and Asia. Intermediate risk destinations include Southern European countries and a few Caribbean islands. Low risk destinations include Canada, Northern Europe, Japan, Australia, New Zealand, the United States and other Caribbean islands. There is no information to support any noninfectious cause of TD such as changes in diet, jet lag, altitude, fatigue, etc.

PREVENTION of TD Possible approaches to prevention of TD include careful food and drink preparation, use of medications other than antibiotics and preventive antibiotics.

Meticulous attention to food and beverage preparation, as mentioned above, can decrease the likelihood of developing TD, however most travelers have difficulty observing the needed dietary precautions. No available vaccines are available and none is expected soon. 

Several non-antibiotic medicines have been advocated for prevention of TD. Controlled studies indicate that preventive use (i.e. use before the onset of diarrhea) of diphenoxylate (brand name Lomotil) actually increases the incidence of TD in addition to producing other undesirable side effects. Antimotility agents (eg diphenoxylate and loperamide, brand name Imodium) are not effective in preventing TD. No data support the preventive use of activated charcoal.

Bismuth subsalicylate (the active ingredient of Pepto-Bismol), 2 oz four times daily or 2 tablets four times daily, has decreased the incidence of diarrhea by about 60 percent in several placebo controlled studies. Side effects include temporary blackening of tongue and stools, occasional nausea or constipation, and rarely, ringing or buzzing in the ears. There is not enough information to exclude risk from using large doses of bismuth subsalicylate for a period of several weeks or more. Bismuth subsalicylate should be avoided by persons with aspirin allergy or gout, those who are on anticoagulant therapy or persons taking probenecid or methotrexate. In people already taking salicylates (aspirin and others) for arthritis, large doses of bismuth subsalicylate can produce toxic serum salicylate concentrations. Bismuth subsalicylate appears to be effective prevention for TD, but is not recommended for periods of more than three weeks. Further studies of the effectiveness and side effects of lower dose regimens are needed. 

Antibiotics do not prevent TD and are not recommended for prevention. Available data regarding prevention support only the recommendation that travelers be instructed in sensible dietary practices. This recommendation is justified by the excellent results of early treatment of TD as outlined below.

DYSENTERY Dysentery, more severe than Traveler’s Diarrhea and may be associated with fever, blood in the stool or significant abdominal pain or vomiting, may be due to other bacteria and will respond to a longer course of ciprofloxacin or azithromycin. Cipro should not be used in pregnancy. Travelers with signs of dysentery generally should not self administer antibiotics or antimotility agents and should seek prompt medical care. A good strategy for those without easy access to medical care during their travels might be to use one dose of cipro or azithromycin for milder “Montezuma’s Revenge”, but treat with cipro twice daily or azithromycin daily for five days for dysentery or more severe or prolonged diarrhea. Self treatment for dysentery should probably be restricted to those who will not have ready access to medical care and the means to arrive at an exact diagnosis.

TREATMENT of TD Once diarrhea has begun, relief from abdominal cramps and diarrhea are needed. Many agents have been proposed to control these symptoms, but few have been demonstrated to be effective by rigorous clinical trials.

Nonspecific Agents: A variety of "adsorbents" have been tried in treating diarrhea. Activated charcoal has been found to be ineffective in the treatment of diarrhea. Kaolin and pectin have been widely used for diarrhea. The combination appears to give the stools more consistency but has not been shown to decrease cramps and frequency of stools nor to shorten the course of diarrhea. Lactobacillus preparations and yogurt have also been advocated; there is one study which suggests benefit. Bismuth subsalicylate preparations (one tablet every 30 minutes for eight doses) have been shown to decrease diarrhea and shorten the duration of illness in several placebo controlled studies. Treatment was limited to 48 hours with no more than 8 doses in a 24 hour period. There is concern about taking, without medical supervision, large amounts of bismuth and salicylate, especially in individuals who may be intolerant to aspirin or aspirin-like medicines, who have kidney disease or who take salicylates for other reasons.

Oral fluids: Most cases of diarrhea are self limited and require only oral replacement of fluids and salts which have been lost in diarrheal stools. Fluid and electrolyte balance can be maintained by (safe) fruit juices, soft drinks (preferably caffeine free and alcohol free) and salted crackers. Iced drinks and noncarbonated bottled fluids made from water of uncertain quality should be avoided. Dairy products aggravate diarrhea in some people and should be avoided. Travelers may prepare their own fruit juice from fresh fruit. Individuals with dehydrations may require fluid and salt replacement in the form of Oral Rehydration Solution (ORS) recommended by the World Health Organization (see article in “Health Information for International Travel” -The Yellow Book). Each ORS packet, available at stores or pharmacies in almost all developing countries, should be added to a liter of boiled or treated water, and consumed or discarded within 12 hours if held at room temperature, or within 24 hours if held refrigerated. 

Antimotility Agents which act directly on the bowel may slow diarrhea of any cause and should only be used if significant abdominal pain, significant vomiting, fever (over 100.5 degrees F) and bloody diarrhea are absent. Natural opiates (codeine and others) have long been used to control diarrhea and cramps. Synthetic agents such as loperamide (available as 2 mg pills without prescription both generically and as brand name Imodium) usually provides prompt, temporary symptomatic relief of uncomplicated TD. The usual dose is 2 tablets at onset then one tablet after each loose stool. Diphenoxylate (brand name Lomotil) is less effective, available by prescription only and is not recommended. Neither diphenoxylate nor loperamide should not be used in children under the age of 2 years.

Antibiotic Treatment: Travelers who develop diarrhea (any loose stool) may benefit from antibiotic treatment. A typical three day illness can often be shortened to one day with early self treatment with an antibiotic. Those with the following should be evaluated by a local physician promptly: fever, more than mild vomiting or mild abdominal pain, blood in the stool, or diarrhea which is severe or which does not resolve within 48 hours.  Nausea and vomiting without diarrhea should not be treated with antibiotics.

Options for antibiotic treatment include ciprofloxacin, TMP/SMX (Bactrim, Septra), trimethoprim and azithromycin (doses of three of these antibiotics are listed below). For ordinary TD, antibiotics and antimotility agents may be stopped when normal stools resume.

For management of infants with diarrhea, see the section in the CDC’s book “Health Information for International Travel”.

* Persons who weigh less than 100 pounds should take half does of  trimethoprim and loperamide.

(Adapted from Health Information for International Travel, Centers for Disease Control)

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©  John D. Wilson, M.D. 1999-2004; Last Update 4/19/2005