Hepatitis A virus can cause fatal liver injury

It is an immediate, intrinsic response of the hepatitis A virus (HAV) infected cell that results in liver inflammation, a new study suggests.

Hepatitis researchers have long thought that immune cells sent by the body to attack virus-infected cells in the liver cause the acute liver injury associated with HAV and other hepatitis viruses.

The virus evokes a response in the infected cell that activates a pre-programmed cell death pathway.

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.

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. 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.

For decades, researchers believed only primates - humans, chimpanzees and a few species of monkeys could be infected by HAV. However, researchers recently discovered the virus could jump species.

Hepatitis A is primarily a food-borne illness

Hepatitis A is the mildest of the hepatitis viruses that affect humans. However, it can cause symptoms that last for several months in some people. Unlike hepatitis B, which is transmitted via blood and sexual contact, hepatitis A is primarily a food-borne illness. It can also be contracted directly from someone with the virus who does not wash their hands properly after being to the toilet.

Many of the cases detected have been linked to the consumption of frozen berries. The time from eating these infected strawberries, raspberries and blueberries until the onset of illness could be anything from 15 to 50 days.

Symptoms include high temperature, nausea and loss of appetite. Abdominal pain also occurs, along with a sense of fatigue. These may be followed by jaundice, in which the skin and eyes go yellow due to excessive levels of a substance called bilirubin in the blood.

The virus attacks the liver, causing inflammation. As a result various liver enzymes are elevated; by measuring these through blood samples doctors can monitor the progress of the infection.

 

There is no treatment in western medicine other than symptom management. There is a vaccine against the virus and this is recommended for people travelling to areas where it is endemic.

Almost everyone who gets hepatitis A recovers completely and does not develop any lasting liver damage, although they may feel sick for months.
 

In rare cases it can cause liver failure and death; this occurs more commonly in people over 50 and in those who already have other liver diseases such as hepatitis B or C.