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
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 two weeks 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
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
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.