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Hepatitis
Hepatitis, or inflammation of the liver, is
caused by living organisms (viruses and bacteria)
or toxic chemicals. One of the biggest public
health problems worldwide is viral hepatitis.
The term viral hepatitis most commonly refers
to one of five forms of the disease, each caused
by a different virus. These diseases are designated
hepatitis A through E.
Currently vaccines are available for Hepatitis
A and B. Of the five types, Hepatitis A and E
spread mainly through contaminated food and water;
Hepatitis B, C, and D spread through blood and
blood products, contaminated needles and sexual
contact with an infected person.
Symptoms of hepatitis include:
- Nausea
- Vomiting
- Abdominal cramps
- Jaundice (yellowing of the skin)
Infected individuals may not show any symptoms
at all, but can still spread the disease. The
severity of illness in infected people who develop
symptoms varies not only according to type, but
also between people infected with the same type
of viral hepatitis.
Viral hepatitis can be fatal by itself. In other
cases viral hepatitis can cause chronic liver
infection, which may ultimately lead to liver
cirrhosis or liver cancer, resulting in premature
death. The incidence of chronic infection varies
with the type of disease.
Hepatitis A
(See the World
Health Organization's web site for a map of countries with moderate to
high risk of infection)
Hepatitis A virus (HAV) is spread through fecal
(stool) contamination of water and food. Travelers
to Asia (except Japan), Africa, Mexico, Central
and South America, and the Caribbean islands
are at risk of HAV infection. According to the
CDC, Hepatitis A is the most common vaccine-preventable
disease in travelers.
Symptoms of HAV infection, if they occur, will
take from twoweeks to 50 days to appear. Young
children may not show symptoms at all — the
severity of the symptoms increases with age.
The virus doesn't cause chronic infection, but
severe complications from HAV infection include
an acute, intense disease that can lead to liver
failure. Approximately 50 percent of patients
with this complication die and others may require
a liver transplant to survive. HAV infection
can produce debilitating symptoms that last or
relapse over a period of six to nine months.
To prevent exposure to HAV, you should:
- Avoid raw or undercooked food.
- Avoid fruits and vegetables unless you peeled
them yourself — they may have been irrigated
with contaminated water.
- In areas where water safety is questionable,
boil all drinking water or treat it with chemical
water-purifying tablets (available at sporting
good stores).
- Avoid beverages with ice in them. If purifying
or boiling water is not an option, use bottled
water not only for drinking but also for washing
hands and brushing teeth.
- Avoid unbottled beverages, or ones that look
murky.
- Avoid food from street vendors.
- Hand washing before each meal is essential.
These precautions will help protect you not
only from HAV infections, but also from travelers'
diarrhea and other food-and-water-borne diseases.
A vaccine is available for Hepatitis A and can
be given to anyone over the age of 2. Its safety
has not been studied in pregnant women, but the
vaccine is made with a killed virus so the risk
to the fetus is probably low. The vaccine requires
two doses. A high level of protection is achieved
within a month after the first dose in over 90
percent of people receiving the vaccine. This
vaccine is still beneficial even when given less
than a month before departure.
Human antibodies (immunoglobulins) can be used
either as a short-term preventive measure against
HAV infection or as an immediate post-exposure
treatment. Anti-HAV immunoglobulins can protect
a person against HAV infection for 2-4 months,
depending on the dosage. Their protective effect
is immediate. Immunoglobulins given within two
weeks of exposure to HAV can prevent Hepatitis
A in over 85 percent of exposed persons.
A combined HAV/HBV vaccine is also available.
Immunity after vaccination lasts at least 15
years (this is the longest time vaccine recipients
have been followed, to date). Researchers theorize
the vaccine may actually establish lifetime immunity.
The HAV vaccine can be used to treat people who
have been exposed to HAV, in order to prevent
the disease from developing.
Hepatitis B
(See the World
Health Organization's web site for a map of countries with moderate to
high risk of infection)
Hepatitis B virus (HBV) is spread through bodily
fluids. The virus is found worldwide in different
frequencies, the highest being in Africa, Southeast
Asia, most of the Middle East, South and West
Pacific islands, Mexico and Central America.
HBV can cause chronic infection resulting in
active liver disease that leads to cirrhosis
or cancer and premature death. Not all infected
individuals show symptoms, and symptoms, if present,
can take up to six months to develop.
Some of the ways in which people can be exposed
to HBV are:
- Unprotected sex
- Blood transfusions
- Sharing contaminated needles and razors.
When traveling, you should remember that contaminated
needles might be found not only among drug
users or in poor hospitals, but also in tattoo
parlors and acupuncture clinics.
The risk of accidental injury, especially from
traffic accidents, is much higher for travelers
than for people in their own environment. These
injuries may require medical treatments that
involve injections, IVs, or blood transfusions,
increasing the risk of exposure to HBV. Elderly
travelers, especially those with heart trouble,
may also require medical treatments that involve
the same risks of exposure.
A Hepatitis B vaccine is available and considered
safe to all people. All international travelers
should receive this vaccine prior to departure.
The vaccine requires three doses, usually given
over a six to 18 month period. However, an effective
accelerated schedule of three doses given over
21 days is available. When the accelerated schedule
is used, a booster given 12 months later is advised.
A combined HAV/HBV vaccine is also available
and can also be given with this accelerated schedule.
An HBV vaccine can be used to treat people who
have been exposed to HBV, in order to prevent
the disease from developing.
Hepatitis C
(See the World
Health Organization's web site for a map of countries with moderate to
high risk of infection)
Hepatitis C virus (HCV), like HBV, spreads through
blood and bodily fluids. The same risks for exposure
to HBV apply to HCV. There is no reliable data
on the incidence of the virus world-wide. Currently
there is no vaccine or treatment for HCV, and
the best prevention is behavior modification
that decreases the risk of exposure.
HCV usually produces no symptoms, and if symptoms
are present they are mild. However, up to 85
percent of people infected with HCV will develop
chronic infection, of which roughly 70 percent
will advance to active liver disease and premature
death from cirrhosis or liver cancer.
Hepatitis D
The Hepatitis D virus (HDV) requires the presence of HBV to become infective.
HDV spreads in the same way that HBV does, therefore prevention of HBV will
prevent HDV, and the HBV vaccine (if given before exposure to HBV) will indirectly
protect against HDV. People already infected with HBV are at risk of acquiring
an HDV infection, and should modify their behavior accordingly to reduce
the risk of this additional infection. Studies estimate that roughly 80 percent
of people with HBV infection who acquire HDV infection will develop chronic
liver disease with cirrhosis, compared to 15 to 30 percent of people with
HBV infection alone.
Hepatitis E
Hepatitis E spreads mainly through contaminated water, and the same precautions
taken against Hepatitis A with regards to drinking water apply to Hepatitis
E. Symptoms are mostly the same as Hepatitis A, and as is the case in HAV,
there is no chronic infection. However, the fatality rate in pregnant women
(especially in the last trimester) is much higher in Hepatitis E, and can
reach 20 percent.
There is no vaccine against, or treatment for,
Hepatitis E. It is mostly found in developing
countries where water treatment is poor or non-existent.
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