Hepatitis = 'inflammation of the liver' and as such is not a single disease (just like 'cancer'). Because of the central role of the liver in metabolism, just about all viruses are capable of involving the liver in some instances, however, there are at least six viruses which specifically seem to infect and damage hepatocytes. No two of these belong to the same family!
Definitions:
- Acute: Short term and/or severe.
- Chronic: Lingering or lasting - may or may not be severe.
- Fulminant: Developing quickly and lasting a short time, high mortality rate.
- Cirrhosis: Hardening: may be the result of infection or toxins (e.g. alcohol)
- Jaundice: Yellowing of the skin, eyes, etc due to raised levels of bilirubin in the blood due to liver damage.
Non-A, Non-B (NANB) Hepatitis:
Acute, infectious hepatitis was recognised in 1885, but the first infectious agent (HBV) was not identified until the 1960's. HAV was isolated in 1973, but this still left many cases which could not be ascribed to either virus, referred to as 'NANBH'. (N.B. There are many non-infectious causes of hepatitis, e.g. toxins, drugs, autoimmunity).
Non-A-E Hepatitis:
Now that many human hepatitis viruses have been identified, the cause of
10-20% of acute A-E seronegative hepatitis cases remains unknown.
How many more viruses wait to be discovered?
Hepatitis viruses in non-human primates. J Med Primatol. 2006 35: 384-7.
