Hepatitis may be defined as infection of liver caused by viruses like hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus, and hepatitis E virus (HEV). Hepatitis caused by other than HAV & HBV is called non - A non - B hepatitis.
Hepatitis is also caused by cytomegalo virus, Epstein - Barr virus, yellow fever virus and Rubella virus. Viruses of herpes simplex, varicella and adenovirus can also cause severe hepatitis in immune compromised patients.
Approximately 4 million people in India suffer every year from one or the other form of acute viral hepatitis.
Hepatitis - A
It is formerly known as infectious” hepatitis or epidemic jaundice caused by hepatitis A virus. Risk of transmitting HAV is greatest from 2 weeks before and 1 week after the onset of jaundice. Incubation period of HAV is 15 to 45 days.
1.Hepatitis – A - Modes of transmission
a. Fecal-oral route- is the major route of transmission. It may occur by direct (person to person) contact (or) indirect by way of contaminated water, food or milk.
b. It rarely transmits through parental route and through sex (Homosexuals)
2. Hepatitis – A -Clinical features
The clinical symptoms of Hepatitis A occur in 3 phases
i. There is an initial prodromal phase lasting for 2 - 5 days characterised by anorexia (loss of appetite), nausea, malaise and mild fever. Severe vomiting may also occur.
ii. This is followed by Icteric phase with onset of jaundice, dark coloured urine and pale stools.
iii. Recovery phase is characterized by gradual resolution of symptoms.
3. Control and treatment Pre exposure prophylaxis can be given to the people who migrate to endemic area.
ii. Post exposure prophylaxis is with Immune serum globulin (0.02 mI/kg) given intramuscularly with in 2 weeks of exposure.
iii. There is no specific vaccine for HAV.
HB virus is present in blood saliva, vaginal secretions and semen of infected persons. The disease may be transmitted to others either during the incubation period or acute phase of the disease. The Incubation period of HB virus is 45 to 180 days.
1. Hepatitis B-Mode of transmission
i. It is transmitted by transfusion of infected blood and blood products, dialysis, contaminated syringe needle pricks to skin and through surgical & dental procedures.
It may be transmitted from HBV carrier mothers to their babies.
ii. 2.Hepatitis B- Clinical features
The clinical symptoms of hepatitis B are similar to other types of viral hepatitis.
But it is complicated by carrier state and by chronic liver disease which nay follow the infection. Chronic liver disease may lead to primary liver cancer.
iii. 3.Hepatitis B- Prevention and treatment
There is no specific treatment for Hepatitis B. However, the following preventive measures can be taken in the form of vaccines.
i. Hepatitis Plasma derived vaccine
This vaccine is given in 3 does at 0, 1st and 6th months. Each dose contains 1 ml of vaccine. It should be given intramuscularly. Children under 10 years of age should be given half of the above close at same time intervals. Booster doses may be given a ter 3 - 8 years.
ii. Hepatitis B-Recombinant DNA - Yeast derived vaccine
This vaccine is given in a dose of 10-20 ig initially and again at 1st and 6th month.
If a person shows the symptoms immediately after receiving Hepatitis B positive blood, Hepatitis ‘B’ immunoglobin I (HBIG) injection may be given for protection. Two doses
cn HBIG should be given (0.05 to 0.07 mI/kg of body weight) at an interval of 30 days.
Hepatitis C virus is the commonest cause of post transfusion hepatitis. The virus is mainly transmitted through transfusion of contaminated blood products. 50% of cases are related to intravenous drug user’s needles.
The incubation period from 6 - 7 weeks. There is 50% incidence of chronic hepatitis, which may lead to cirrhosis of liver or liver cancer. Interferon is the only drug that has been found effective in the treatment of HCV infection.
Hepatitis D virus alone cannot cause hepatitis. Hepatitis 0 or Delta infection occurs either as a concomitant infection of HDV with hepatitis B or as a super infection. It occurs among drug addicts and hemophiliacs.
Delta hepatitis can be an acute or a chronic hepatitis with the latter frequently leading to hepatic cirrhosis. Treatment, prevention and mode of transmission are same as that of Hepatitis D.
The infection caused by the hepatitis E virus is essentially a water borne disease. After an incubation period of 2 - 9 weeks, a self limiting acute viral hepatitis appears, lasting for a period of several weeks, followed by recovery. Clinical features are similar to Hepatitis ‘A’ infection.