Frequently Asked Questions
Who gets travelers'
diarrhea?
Travelers' diarrhea (TD) is the most common illness affecting
travelers. Each year between 20%-50% of international travelers,
an estimated 10 million persons, develop diarrhea. The onset of
TD usually occurs within the first week of travel but may occur
at any time while traveling, and even after returning home. The
most important determinant of risk is the traveler's destination.
High-risk destinations are the developing countries of Latin America,
Africa, the Middle East, and Asia. Persons at particular high-risk
include young adults, immunosuppressed persons, persons with inflammatory-bowel
disease or diabetes, and persons taking H-2 blockers or antacids.
Attack rates are similar for men and women. The primary source
of infection is ingestion of fecally contaminated food or water.
What are common
symptoms of travelers' diarrhea?
Most TD cases begin abruptly. The illness usually results in
increased frequency, volume, and weight of stool. Altered stool
consistency also is common. Typically, a traveler experiences
four to five loose or watery bowel movements each day. Other commonly
associated symptoms are nausea, vomiting, diarrhea, abdominal
cramping, bloating, fever, urgency, and malaise. Most cases are
benign and resolve in 1-2 days without treatment. TD is rarely
life-threatening. The natural history of TD is that 90% of cases
resolve within 1 week, and 98% resolve within 1 month.
What causes travelers'
diarrhea?
Infectious agents are the primary cause of TD. Bacterial enteropathogens
cause approximately 80% of TD cases. The most common causative
agent isolated in countries surveyed has been enterotoxigenic
Escherichia coli (ETEC). ETEC produce watery diarrhea with
associated cramps and low-grade or no fever. Besides ETEC and
other bacterial pathogens, a variety of viral and parasitic enteric
pathogens also are potential causative agents.
What preventive
measures are effective for travelers' diarrhea?
Travelers can minimize their risk for TD by practicing the following
effective preventive measures:
- Avoid eating foods or drinking beverages purchased from street
vendors or other establishments where unhygienic conditions
are present
- Avoid eating raw or undercooked meat and seafood
- Avoid eating raw fruits (e.g., oranges, bananas, avocados)
and vegetables unless the traveler peels them.
If handled properly well-cooked and packaged foods usually are
safe. Tap water, ice, unpasteurized milk, and dairy products are
associated with increased risk for TD. Safe beverages include
bottled carbonated beverages, hot tea or coffee, beer, wine, and
water boiled or appropriately treated with iodine or chlorine.
Is prophylaxis
of travelers' diarrhea recommended?
CDC does not recommend antimicrobial drugs to prevent TD. Studies
show a decrease in the incidence of TD with use of bismuth subsalicylate
and with use of antimicrobial chemoprophylaxis. Several studies
show that bismuth subsalicylate taken as either 2 tablets 4 times
daily or 2 fluid ounces 4 times daily reduces the incidence of
travelers' diarrhea. The mechanism of action appears to be both
antibacterial and antisecretory. Use of bismuth subsalicylate
should be avoided by persons who are allergic to aspirin, during
pregnancy, and by persons taking certain other medications (e.g.,
anticoagulants, probenecid, or methotrexate). In addition, persons
should be informed about potential side effects, in particular
about temporary blackening of the tongue and stool, and rarely
ringing in the ears. Because of potential adverse side effects,
prophylactic bismuth subsalicylate should not be used for more
than 3 weeks.
Some antibiotics administered in a once-a-day dose are 90% effective
at preventing travelers' diarrhea; however, antibiotics are not
recommended as prophylaxis. Routine antimicrobial prophylaxis
increases the traveler's risk for adverse reactions and for infections
with resistant organisms. Because antimicrobials can increase
a traveler 's susceptibility to resistant bacterial pathogens
and provide no protection against either viral or parasitic pathogens,
they can give travelers a false sense of security. As a result,
strict adherence to preventive measures is encouraged, and bismuth
subsalicylate should be used as an adjunct if prophylaxis is needed.
What treatment
measures are effective for travelers' diarrhea?
TD usually is a self-limited disorder and often resolves without
specific treatment; however, oral rehydration is often beneficial
to replace lost fluids and electrolytes. Clear liquids are routinely
recommended for adults. Travelers who develop three or more loose
stools in an 8-hour period---especially if associated with nausea,
vomiting, abdominal cramps, fever, or blood in stools---may benefit
from antimicrobial therapy. Antibiotics usually are given for
3-5 days. Currently, fluoroquinolones are the drugs of choice.
Commonly prescribed regimens are 500 mg of ciprofloxacin twice
a day or 400 mg of norfloxacin twice a day for 3-5 days. Trimethoprim-sulfamethoxazole
and doxycycline are no longer recommended because of the high
level of resistance to these agents. Bismuth subsalicylate also
may be used as treatment: 1 fluid ounce or 2 262 mg tablets every
30 minutes for up to eight doses in a 24-hour period, which can
be repeated on a second day. If diarrhea persists despite therapy,
travelers should be evaluated by a doctor and treated for possible
parasitic infection.
When should
antimotility agents not be used to treat travelers' diarrhea?
Antimotility agents (loperamide, diphenoxylate, and paregoric)
primarily reduce diarrhea by slowing transit time in the gut,
and, thus, allows more time for absorption. Some persons believe
diarrhea is the body's defense mechanism to minimize contact time
between gut pathogens and intestinal mucosa. In several studies,
antimotility agents have been useful in treating travelers' diarrhea
by decreasing the duration of diarrhea. However, these agents
should never be used by persons with fever or bloody diarrhea,
because they can increase the severity of disease by delaying
clearance of causative organisms. Because antimotility agents
are now available over the counter, their injudicious use is of
concern. Adverse complications (toxic megacolon, sepsis, and disseminated
intravascular coagulation) have been reported as a result of using
these medications to treat diarrhea.
What is CDC doing
to prevent travelers' diarrhea?
CDC, in collaboration with the World Health Organization and
several Ministries of Health, is working to improve food and water
safety around the world. CDC also investigates risk factors associated
with acquisition of TD, to assist in identifying more effective
preventive measures. CDC continues to monitor antimicrobial resistance
in other countries and in the United States. In addition, CDC,
in collaboration with international agencies, is working to improve
sanitary conditions in foreign accommodations (e.g., tourist resorts)
and frequently consults with travel medicine specialists and local
and state health departments. CDC is responsible for evaluating
sanitation on cruise ships docking in US ports.
Please visit CDC's
Traveler's Health site for more information about the vessel
sanitation program and for a summary of recent vessel inspections.
How can I learn
more about travelers' diarrhea?
Potential travelers should consult with a doctor or a travel
medicine specialist before departing on a trip abroad. Information
about TD is available from your local
or state health departments or the World
Health Organization (WHO).
Other information that may be of interest to travelers can be
found at the CDC Travelers' Health homepage at http://www.cdc.gov/travel.
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