Hepatitis

Some chronic forms of hepatitis show very few of these signs and only present when the longstanding inflammation has led to the replacement of liver cells by connective tissue; the result is cirrhosis. Certain liver function tests can also indicate hepatitis.


Types of hepatitis

Viral

Most cases of acute hepatitis are due to viral infections:

• Hepatitis A
• Hepatitis B
• Hepatitis C
• D-agent (requires presence of the hepatitis B virus)
• Hepatitis E
• Hepatitis F (discredited)
• Hepatitis G

Hepatitis B causes both acute and chronic hepatitis in some patients who are unable to eliminate the virus. Identified methods of transmission include blood (blood transfusion, now rare), tattoos (both amateur and professionally done), sexually or vertically (from mother to her unborn child). However, in about half of cases the source of infection cannot be determined. Blood contact can occur by sharing syringes in intravenous drug use, shaving accessories such as razor blades, or touching wounds on infected persons. Needle-exchange programmes have been created in many countries as a form of prevention. In the developed countries, 95% of patients clear their infection and develop antibodies against Hepatitis B virus. 5% of patients do not clear the infection and develop chronic infection; only these people are at risk of long term complications of Hepatitis B.

Patients with chronic hepatitis B have antibodies against Hepatitis B, but these antibodies are not enough to clear the infection that establishes itself in the DNA of the affected liver cells. The continued production of virus combined with antibodies is a likely cause of immune complex disease seen in these patients. A vaccine is available that will prevent infection from hepatitis B for life. Hepatitis B infections result in 500,000 to 1,200,000 deaths per year worldwide due to the complications of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Hepatitis B is endemic in a number of (mainly South-East Asian) countries, making cirrhosis and hepatocellular carcinoma big killers. There are three, FDA-approved treatment options available for persons with a chronic hepatitis B infection: alpha-interferon, adefovir and lamivudine. In about 45% of persons on treatment achieve a sustained repsonse. Read more on Hepatitis B » here.

Hepatitis C (originally "non-A non-B hepatitis") is probably not transmitted sexually but only by blood contact. It leads to a chronic form of hepatitis, culminating in cirrhosis. It can remain asymptomatic for 10-20 years. No vaccine is available for hepatitis C. Patients with hepatitis C are prone to severe hepatitis if they contract either hepatitis A or B, so all hepatitis C patients should be immunized against Hepatitis A and Hepatitis B if they are not already immune.

Two other hepatitis viruses are known, hepatitis D and E. The D agent, an RNA passenger virus, cannot proliferate without the presence of hepatitis B virus, because its genome lacks certain essential genes. Hepatitis E produces symptoms similar to hepatitis A, although it can take a fulminant course in some patients, particularly pregnant women; it is more prevalent in the Indian subcontinent.

Hepatitis G

Hepatitis G Virus (HGV) is also known as GB virus-C (GBV-C). HGV and GB virus-C were discovered about the same time, and are thought to be different strains of the same virus. HGV/GBV-C is a single stranded RNA virus belonging to the Flaviviridae family.

This is the most recently discovered hepatitis virus. It almost looks similar to Hepatitis C Virus(HCV), it shares about 85 percent of its genetic sequence with that virus. Till date through the researches made it doesn't seem to be infectious or to cause illness.

Hepatitis G is an RNA virus that is very similar to Hepatitis C. However, it has not been associated with any chronic liver disease. In fact, it seems to be a benign virus that is widely present throughout the world. There has been no association between poor outcomes of patients who are infected with Hepatitis C and Hepatitis G at the same time. There are are recorded evidences of about 900 and 2,000 cases of hepatitis G infection each year in the US alone and the world wide data is still being compiled.

It was discovered after people who had a gone through blood transfusion developed post transfusion hepatitis which could not be identified as any known virus. It can occur as a coinfection with hepatitis.

Infection with the hepatitis G virus can lead to persistent infection in 15 to 30% of adults. The long term outcomes of the infection are still unclear. People with hepatitis A, B, or C can be co- or super- infected with hepatitis G. There are no vaccination available for hepatitis G till date though many research are underway to find a vaccine.


Clinical Characteristics

• Carrier rate of between 2 and 5% in the general population.
• Causes persistent infection for up to 9 years in 15-30% of adults.
• HGV/GBV-C is often found in co-infections with other viruses, such as hepatitis C virus (HCV), hepatitis B virus (HBV), and Human Immunodeficiency Virus (HIV)
• There is little proof that Hepatitis G (Hep G) causes serious liver disease at any age. It is possible that HGV/GBV-C may not be a true 'hepatitis' virus.

Signs and Symptoms
Almost no cases have symptoms like the other Hepatitis viruses.

Modes of Transmission
- Transmitted by infected blood or blood products
- HGV/GBV-C can be transmitted by sharing personal items contaminated with the virus and other similar behaviours (parenterally), from mother-to-newborn child at birth (vertical), or various sexual activities.

Other viruses can cause infectious hepatitis

• Mumps virus
• Rubella virus
• Cytomegalovirus
• Epstein-Barr virus
• Other herpes viruses