Diarrhea is a change in one's normal stool pattern in which the stool
becomes more frequent and less formed. It can occur by itself or along
with abdominal cramps, bloating, nausea, vomiting and fever. When diarrhea
occurs, the normal function of the intestine is disrupted. Instead of
absorbing fluids and nutrients from the material passing through, it
reverses that process and secretes body fluids back into itself and
passes them out of the body.
Traveler's Diarrhea is
the term used to describe the diarrhea that strikes international travelers
from countries with good hygiene to countries that have poor public
sanitation and hygiene. It is caused by infection with one of a number
of bacteria, protozoa or viruses that are ingested by eating food or
drinking water that has been contaminated by stool.
Dysentery is a more severe
form of diarrhea in which white cells and mucus - and occasionally blood
- appear in the stool. It usually includes cramps and fever. Dysentery
should not be thought of as a separate disease, but simply one end of
the spectrum of diarrhea disease.
Risk of Traveler's Diarrhea
Your destination is the most important determinant of risk. People who
travel from developed countries to developing countries are at risk
to accidentally ingest infectious organisms that can cause diarrhea.
Studies usually show that 30-40% of people experience an episode of
diarrhea in the first 2 weeks of travel in high-risk destinations. Almost
all developing countries in Latin America, Africa, the Middle East and
Asia are considered high risk. Most countries in Southern Europe and
most Caribbean islands are deemed intermediate risk. Low risk areas
include the United States, Canada, Northern Europe, Australia, New Zealand
and a few of the Caribbean islands.
Prevention
You can prevent TD if you can avoid eating food or drinking water that
is contaminated with stool. However, this is harder than it might seem
in countries with a poor ability to dispose of stool safely. The basic
idea is to treat all water as if it is potentially contaminated and
to avoid foods that are likely to be contaminated.
You can lower your risk
of getting TD by understanding and using the following guidelines:
- Boiling is the best
way to make water safe to drink.
- All organisms that cause
TD are highly susceptible to heat, and they die at temperatures higher
than 70°C (158°F). The time it takes for water to reach its boiling
point and then return to a temperature below 70°C provides enough
contact time to kill all TD-causing organisms - even when altitude
is taken into account. Thus, water boiled for any length of time,
at any altitude, is safe to drink.
- However, the U.S. Centers
for Disease Control and Prevention (CDC) takes a more conservative
approach, recommending that you bring water to a full boil for 1 minute
at altitudes below 6,500 feet (2 km) and for 3 minutes at altitudes
above that level. You can improve the taste of boiled water by adding
a pinch of salt to each quart or by pouring water back and forth several
times between containers to aerate it.
- When you cannot boil
water, you can disinfect it using chemicals.
- Iodine can kill most
(but not all) organisms that cause diarrhea, and you can use it to
disinfect water, leafy vegetables and fruits. You can also use chlorine,
but its ability to kill germs varies greatly with temperature and
other factors; thus, it is less reliable than iodine. Iodine and chlorine
cannot kill some organisms, including Cryptosporidium and Cyclospora.
- To disinfect water with
iodine, use tincture of iodine (2% solution).
- To disinfect clear water,
add 5 drops of tincture of iodine (1 drop = 0.05 ml) to 1 quart or
liter of water and let the water stand for 30 minutes before using.
- To disinfect very cold
or cloudy water, add 10 drops of tincture of iodine to 1 quart or
liter of water and let the water stand for several hours if possible.
- Tetraglycine hydroperiodide
tablets (such as Globulin, Potable-Aqua, Coghlan's), available from
pharmacies and sporting goods stores, are also a well-tested method
of chemical disaffection. Follow the manufacturer's instructions for
use. [Use of trade names is for example purposes only and does
not imply endorsement.]
- If you want to avoid
the taste and smell of iodine in the disinfected water, you can add
vitamin C (ascorbic acid) after the iodine has been in contact with
the water for 30 minutes or more. Adding about 50 mg of vitamin C
to a liter of water and shaking briefly will completely eliminate
the iodine taste and odor.
- Do not assume that portable
filters will make drinking water safe: CDC makes no recommendation
about their use because there have not been enough independent studies
done to confirm their effectiveness. However, in areas where there
is a risk of Cryptosporidium or Cyclospora and boiling all drinking
water is not practical, a good quality filter with a pore size of
0.2 microns will eliminate the risk of these 2 organisms. You should
then treat the filtered water chemically as well.
- All bottled or canned
carbonated beverages are inherently safe to drink because carbonation
makes the drinks acidic, which kills bacteria and other organisms.
- Water on the outside
of cans or bottles might be contaminated; you should dry wet cans/bottles
before opening them and clean surfaces that will have contact with
your mouth.
- Non-carbonated water
that is bottled or canned in developing countries, even if factory
sealed, may not be any safer than tap water - remember, tap water
should not even be used for brushing teeth.
- Hot tea and hot coffee
made with boiling water are safe to drink.
- Beer and wine are safe
to drink, but alcohol added to beverages does not make them safe.
- Ice is not safe unless
it is made from previously treated water - freezing does not kill
the organisms that cause diarrhea.
- Avoid un-pasteurized
milk and milk products (such as cheese), as well as any milk that
has not been boiled.
- Cooked food must be
heated thoroughly and served steaming hot.
- Avoid foods such as
lasagna, quiche, and casseroles that have been cooked earlier and
then served without sufficient re-heating.
- Only eat fruit that
you can peel yourself.
- Avoid salads and uncooked
vegetables.
- In many areas, human
and animal feces are used as fertilizer. The bacteria or parasitic
cysts in the feces can contaminate fruits and vegetables grown in
the fertilized soil - especially items such as lettuce and spinach
that grow at ground level.
- Avoid raw or undercooked
meat and seafood.
- According to CDC, some
fish may carry toxins in their flesh and are not guaranteed safe even
when cooked. Tropical reef fish, red snapper, amber jack, grouper
and sea bass can occasionally be toxic if caught on tropical reefs
rather than the open ocean. The barracuda and puffer fish are often
toxic and should generally not be eaten. Highest risk areas include
the islands of the West Indies, as well as the Tropical Pacific and
Indian Oceans.
- Food and beverages from
street vendors pose a high risk due to potential exposure to insects
and a less rigorous sanitary environment.
- Breast-feeding is the
safest food source for infants who are still nursing. If your child
is already weaned, carefully prepare formula with boiled water and
sterilized containers.
- If a social situation
arises in which you may have to accept food that may not be safe to
eat, consider selective use of a preventive antibiotic, but only if
you clearly understand the risks and benefits of antibiotic use.
Use
of Antibiotics
and Antiseptics in Prevention
Some drugs and other preparations have been shown to be effective in
preventing a percentage of TD cases. The most effective method is to
take an appropriate antibiotic daily while you travel. This method,
however, has the disadvantage of increasing the number of people who
have adverse reactions to the drug, and it limits the options for treatment
if you get diarrhea in spite of this antibiotic use. Even if you use
preventive antibiotics, you may still be at risk for diarrhea and should
still follow the food and beverage precautions given above.
Bismuth subsalicylate (an
ingredient of Pepto-Bismol) has been shown to decrease TD by about 60%.
However, you have to take up to 8 pills per day, and the medicine can
turn your tongue and stools black. Some people who use this drug also
have nausea and constipation, and sometimes ringing in the ears. You
should not use bismuth subsalicylate if you have an allergy to aspirin,
renal insufficiency, or gout - or if you are taking anticoagulants,
probenecid or methotrexate. Because bismuth subsalicylate can prevent
absorption of doxycycline, you should not use these two drugs together.
In people who take salicylates for arthritis, adding large doses of
bismuth subsalicylate can produce toxic serum concentrations of salicylate.
Bismuth subsalicylate is not approved for use in children under 3 years
old, and it should not be given to children and adolescents who have
the chicken pox or flu because of the potential risk of Reye's syndrome.
Self-Diagnosis and Treatment
Bacteria that are all sensitive to the same type of antibiotic cause
the majority of TD cases. Thus, self-treatment is a realistic option
for travelers who may not have access to reliable health care while
traveling. In fact, many third-world laboratories lack experienced personnel
who can reliably identify the organism that's causing your diarrhea.
You're often better off treating your best guess than depending on a
laboratory for a diagnosis.
Causes of Diarrhea
Bacterial Diarrhea
All cases of diarrhea in the first 1-2 weeks of travel are likely to
be due to bacteria. Bacterial diarrhea is characterized by the sudden
onset of relatively uncomfortable diarrhea. This usually means that
you go from feeling fine to feeling fairly ill within a very short time.
You can usually remember the exact time of day when you became ill.
Bacterial diarrhea can also be associated with nausea, vomiting, fever
or severe abdominal cramps. Bacteria cause 80 to 90 percent of traveler's
diarrhea. If you suspect bacterial diarrhea, and you feel ill enough
that you can't carry on with your normal plans, you can take an antibiotic
to shorten the illness to about one day. There are currently 2 antibiotics
that work equally well to treat bacterial diarrhea in adults.
- Ciprofloxacin 500 mg
twice a day (12 hours apart) for 1-3 days
- Norfloxacin 400 mg twice
a day for 1-3 days
Most people start to feel
better within hours of the first dose. Both antibiotics work so rapidly
that the current thinking in travel medicine is that travelers should
avoid taking drugs to prevent TD but be prepared to take the antibiotic
at the onset of bothersome symptoms. Once your diarrhea is gone, stop
taking the antibiotic. It is not necessary to complete a preset number
of doses when taking these antibiotics for this purpose.
The following outlines
how you might approach treating bacterial diarrhea:
- Mild loose stools
without other symptoms: Use of an antibiotic is probably not necessary.
Use bismuth subsalicylate (Pepto-Bismol) or antimotility drug, such
as loperamide (Imodium), if necessary for comfort during sightseeing
or travel. Do not use an antimotility drug for more than 48 hours.
- Moderately loose
or frequent stools with cramps or nausea: Take an antibiotic.
Take an antimotility drug if needed for travel or other activities
(do not use for more than 48 hours).
- Severe diarrhea with
intense cramps, nausea, bloody stools, dehydration, or fever and chills:
Take an antibiotic. Stay in your room and use the toilet as necessary.
Try to avoid taking an antimotility drug unless needed for travel
(if taken, do not use for more than 48 hours). Seek medical attention
if symptoms do not rapidly improve.
Protozoan Diarrhea
The risk of acquiring organisms with longer incubation periods, such
as Giardia Lamblia (giardia) and Entamoeba Histolytica (amoeba) increases
for longer-term travelers. Protozoal diarrhea (giardia and amoeba) is
characterized by a more gradual onset of chronic diarrhea. An infected
person wakes up with a few loose stools, goes out for the day without
difficulty, has another loose stool or two later on, and wonders if
something is wrong. Nausea, vomiting or fever is extremely rare. This
pattern goes on for another few days or weeks before the person feels
ill enough to seek care.
Giardia tends to produce
the same symptoms every day, with an increased amount of gas and a churning
feeling in the intestines. Giardia infections in adults can be treated
with metronidazole 250 mg 3 times per day for 7
days. In Asia and other parts of the world, tinidazole
a single daily dose of 2000 mg (usually 4 pills) for 2 consecutive days.
Amoebas tend to cause alternating
diarrhea and constipation (or at least normal stools) every 2-3 days.
Because of this alternating pattern, travelers often think they are
getting better every few days and often don't seek medical advice for
several weeks. Amoebic infections are the least common (about 1% of
travelers). They can be treated with metronidazole
750 mg 3 times per day for 10 days. Tinidazole
2000 mg. dose daily for 3 days followed by a diloxanide furoate (Furamide)
500 mg. tablet 3 times per day for 10 days.
There are several other
organisms that can occasionally cause diarrhea in travelers, such as
Cyclospora, Cryptosporidium and Dientamoeba fragilis. A stool exam can
lead to a diagnosis if done in a reliable lab, and treatment is available
for some of these infections.
In high-risk
diarrhea areas, it is possible to be infected with more than one organism
at the same time. A good rule to remember is that vomiting almost always
occurs at the beginning of a diarrheal illness and almost never after
the diarrhea has been established for a few days. If vomiting occurs
in the midst of a diarrheal illness, it probably means you have acquired
a new illness.
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