Hepatitis A virus
- Scientists have found that long held belief of immune cell response against Hepatitis A virus leading to liver damage may not be true.
- University of North Caroline researchers find that liver cell suicide during Hepatitis A infection leads to liver damage.
- Hepatitis A virus which is known to infect monkeys, chimpanzees and humans can infect mice also.
affects the liver and leads to mild to severe illness. It has long been believed that immune cells that move into the liver result in damage to the liver cells associated with the infection. However, scientists from the University of North Carolina have identified a new mechanism that could explain the liver damage associated with Hepatitis A infection.
‘Healthy liver cells undergo apoptosis (programmed cell death) on hepatitis A infection.’
Hepatitis A is a liver
disease which is spread when an individual eats contaminated food or water. People who suffer from hepatitis A recover fully but it could be fatal in a small proportion of the people who could die due to fulminant hepatitis. The debilitating symptoms that are caused as a result of fulminant hepatitis could lead to a delayed return to normality, with people staying away from work for many weeks.
Dr. Stanley Lemon from the University of North Carolina who is one of the authors of the study said "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 recognize as hepatitis."
The scientists have found that the destruction of the liver cells is not due to the immune response generated as a result of infection with hepatitis A virus but due to the activation of apoptosis or programmed cell death. Apoptosis is a part of the normal cycle of a cell but the revelation that infection of a virus can induce the cell to start this process of cell destruction is a new discovery.
Symptoms of Hepatitis A
The symptoms of the disease include
- Mild to severe fever
- In children only 10% develop jaundice
- In adults it is more severe, with 70% developing jaundice
Patients are at a risk of relapse and should be safeguarded. The main cause of the spread of infection is poor sanitation.
Virus Found to Jump Species
Another discovery that was revealed by these scientists from The University of North Carolina is that these viruses were found to jump species. The Hepatitis A virus has been known to infect humans and primates like chimpanzees and monkeys. However, when these scientists block intercellular anti-viral response in laboratory mice, they found that these viruses could grow and survive in these mice, essentially jumping species.
Dr. Lemon said "The ability of the virus to jump into mice is dependent upon knocking out the mouse interferon system, which HAV cannot do on its own. Host species jumps are incredibly important for viral emergence, and the factors that control the odds of this happening are not well known. We have defined the host interferon system as a very important barrier to a host species jump."
The mechanisms that have been identified by these scientists will aid in understanding the underlying pathways that lead to fatal conditions associated with the infection of Hepatitis A virus.
Prevention of Hepatitis A Virus Infection
The risk of liver damage that occurs during the infection of Hepatitis A virus warrants preventive steps to be actively taken in order to safeguard against infection.