What causes hepatitis A?

The hepatitis A virus is found in the faeces of an infected person and is usually acquired from hands soiled after using the toilet or changing a nappy, or by swallowing water or food that have been contaminated by human faeces. Uncooked shellfish and raw vegetables contaminated by sewage can also be a route of infection.

Sexual contact with an infected person is also a recognised route of infection.

Hepatitis A infects the liver cells and multiplies inside them. As the body's immune system attempts to destroy the virus, the immune response causes liver cell damage and inflammation. Certain enzymes, usually active inside the liver cells, are released from damaged cells into the blood and can be detected by blood tests, thus confirming the presence of a hepatitis virus.

The swelling of the liver causes blockage of the bile ducts, trapping bile that should flow into the gall bladder inside the liver. The yellow-green bile being absorbed into the bloodstream from the liver causes the yellow discoloration known as jaundice.

A healthcare professional will often be able to detect during examination of the abdomen that the liver is enlarged and tender.