Traveler's
Diarrhea
Whenever
a person travels from one country to another - particularly
if the change involves a marked difference in climate,
social conditions, or sanitation standards and facilities
- diarrhea is likely to develop within 2 - 10 days.
There may be up to ten or even more loose stools per
day, often accompanied by abdominal cramps, nausea,
occasionally vomiting, and rarely fever. The stools
do not usually contain mucus or blood, and aside from
weakness dehydration there are no systemic manifestations
of infection. The illness usually subsides spontaneously
within 1 - 5 days. Although 10% remain symptomatic
for a week or longer, an din 2% symptoms persist for
longer than a month.
Bacteria
cause 80% of cases of traveler's diarrhea, with enterotoxigenic
E coli, shigella species, and campylobacter jejuni
being the most common pathogens. Less common causative
agents include aeromonas, salmonella, noncholera vibrious.
Entamoeba histolytica, and Giardia lamblia. Contributory
causes may at times include unusual food and drink,
change in living habits, occasional viral infections,
and change in bowel flora. In patients with fever
and bloody diarrhea, stool culture may be indicated,
but in most cases cultures are reserved for those
who do not respond to antibiotics. Chronic watery
diarrhea may be due to amebiasis or giardiasis or,
rarely, tropical sprue.
For
most individuals, the affliction is short-lived, and
symptomatic therapy with opioids or loperamide is
all that is required provided the patient is not systemically
ill and does not have dysentery, in which case antimotility
agents should be avoided. Packages of oral rehydration
salts to treat dehydration are available over the
counter in the USA and in many foreign countries.
Avoidance of fresh foods and water sources that are
likely to be contaminated is recommended for travelers
to developing countries, where infectious diarrheal
illnesses are endemic. Prophylaxis is remended for
those with significant underlying disease and for
those whose full activity status during the trip is
so essential that even short periods of diarrhea would
be unacceptable. Prophylaxis is started upon entry
into the destination country and is continued for
1 or 2 days after leaving. For stays of more than
3 weeks, prophylaxis is not recommended because of
the cost and increased toxicity. For prophylaxis,
bismuth subsalicylate is effective but turns the tongue
and the stools black and can interfere with doxycyline
absorption, which may be needed for malaria prophylaxis.
Numerous antimicrobial regimens for once-daily prophylaxis
also are effective, such as n orfloxacin 400 mg, ciprofloxacin
500 mg, lfloxacin 300 mg, or trimethoprim - sulfamethoxazole
160/80 mg. Because not all travelers will have diarrhea
and because most episodes are brief and self-limited,
an alternative approach that is currently recommended
is to provide the traveler with a supply of antimicrobials
to be taken if significant diarrhea occurs during
the trip. Loperamide with a single dose of ciprofloxacin,
or olfloxacin cures most cases of traveler's diarrhea.
If diarrhea is severe, associated with fever or bloody
stools, or persists despite single-dose ciprofloxacin
treatment, then 3 - 5 days of ciprofloxacin 500 mg
twice daily, levofloxacin 500 mg once daily, norfloxacin
400 mg twice daily, or ofloxacin 300 mg twice daily
can be given. Trimethoprim-sulfamethoxazole 160/800
mg twice daily can be used as an alternative, but
resistance is common in many areas.
