International travel and health

Hepatitis A

Cause

Hepatitis A virus (HAV), a member of the Picornaviridae family.

Transmission

The virus is acquired through close contact with infected individuals or through faecally contaminated food or drinking-water. There is no insect vector or animal reservoir.

Nature of the disease

Acute viral hepatitis is characterized by abrupt onset of fever, malaise, nausea and abdominal discomfort, followed by jaundice a few days later. In very young children infection is usually mild or asymptomatic whereas in older children symptomatic disease is common. The disease is often more severe in adults and full recovery may take several months. Case-fatality is greater than 2% for those over 40 years of age and about 4% for those aged 60 years or more.

Geographical distribution

Worldwide, but most common in areas where sanitary conditions are poor (see map).

Risk for travellers

Non-immune travellers to developing countries are at significant risk of infection, particularly in settings with poor food and drinkingwater control and poor sanitation. People born and raised in developing countries, and those born before 1945 in industrialized countries, have usually been HAVinfected in childhood and are likely to be immune.

Precautions

Avoid or boil potentially contaminated food and water.

Short-term protection through injection of human immune globulin is gradually being replaced worldwide by hepatitis A vaccination.

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