It is an immediate, intrinsic response of the hepatitis A virus (HAV)-infected cell that results in liver inflammation, researchers at University of North Carolina at Chapel Hill have discovered.
HAV does not cause chronic liver disease like hepatitis B and C viruses.
But in rare cases, it can cause acute liver failure, which is often fatal.
The new findings, published in the journal Science, could lead to new response to control the infection as hepatitis researchers earlier thought that immune cells sent by the body to attack virus-infected cells in the liver cause the acute liver injury.
"The virus evokes a response in the infected cell that activates a pre-programmed cell death pathway," said one of the study authors Stanley Lemon, Professor of Medicine.
"In effect, the cell commits suicide, sacrificing itself along with the virus in an effort to save the host. This results in inflammation within the liver that we recognise as hepatitis," Lemon explained.
Hepatitis A virus is a vaccine preventable form of infectious hepatitis.
HAV is found worldwide and is transmitted through ingestion of food and water that is contaminated with the feces of an infected person.
Symptoms of hepatitis A include nausea, stomach pain, fever, sore throat, headache and diarrhea.
People infected with HAV may not experience any symptoms, but shed the virus for two to four weeks.
During this period, an infected person can pass the virus to others.