Hepatitis A (Infectious Hepatitis): Hepatitis A was formerly known as infectious hepatitis. It is distributed throughout the world and usually exists in endemic forms. Children are more affected than adults. An attack of hepatitis A generally provides immunity against a second attack. Causative Agent: It is caused by hepatitis A virus which is an enterovirus [a virus that enters the body through the gastro-intestinal tract, multiplies there and then (generally) invades the central nervous system]. The virus is found in abundance in the faeces of the patient during early acute phase of the disease and the latter part of the incubation period. Once jaundice develops, it is rarely detectable in faeces. The virus is present in blood for a short period during pre-icteric stage, but usually disappears when jaundice develops.
This virus is resistant to heat and chemicals. Mode of Spread: Hepatitis A spreads by the following modes: (i) Faecal-oral route is the major route of transmission. It can occur by using contaminated food, water or milk. Flies may act as mechanical carriers. (ii) Disease can spread from person to person by direct contact through contaminated hands or via contaminated articles of use. (iii) Transmission of hepatitis A virus is rare through needles, blood or blood products.
(iv) Infection spreads readily under unhygienic conditions and over crowding. Incubation Period: Incubation period is 15 to 45 days (usually 28 days). Sign and Symptoms: It is clinically characterised by fever, chills, headache, fatigue, generalised weakness and pain followed by nausea, vomiting, dark urine, stools are pale coloured, liver enlarged, appetite is lost and jaundice develops. The patient may recover completely in 3 to 6 weeks or in some cases the patient’s condition may worsen which may lead to coma and death of the patient.
Prevention and Control: (i) Isolate the hepatitis cases. (ii) Disinfect the faeces and fomites of the patient. (iii) Follow personal and community hygienic measures such as washing of hands after toilet and before meals, sanitary disposal of human excreta, using safe drinking water (boiled water should be used during epidemics as virus is not killed by chlorination and by other methods of sterilization) and taking nourishing diet. Enforce sanitary measures in hotels, restaurants and other eating places. (iv) Anti-fly measures should be taken.
(v) Needles and syringes should be properly sterilized. It is advisable to use disposable needles and syringes. (vi) Human normal immunoglobulin should be administered to all contacts before or within a week of exposure. 2. Hepatitis B (Serum Hepatitis): Hepatitis B was formerly known as serum hepatitis. It is an acute systemic infection which affects the liver sometimes leading to cancer of the liver. The disease is endemic throughout the world.
It affects all ages but the incidence is more in adults than in children and in urban areas than in rural areas. Causative Agent: It is caused by hapititis B virus (HBV). Mode of Spread: (i) Parenteral Route: It is transmitted exclusively by parenteral route through infected blood and blood products, through blood transfusion, dialysis, contaminated needles and syringes, ear or nose piercing, tattooing etc. (ii) Infection can spread from mother to foetus in uterus. (iii) Infection may be transmitted by sexual contact or even by kissing. (iv) Blood sucking arthropods such as mosquitoes and bed bugs can transmit the disease. The virus is highly infectious and very minute amounts of some carrier serum can transmit the disease.
Therefore any method that can convey traces of blood or serum from one person to another can spread the infection. Incubation Period: Incubation period of Hepatitis B virus is 60 to 180 days. Signs and Symptoms: The signs and symptoms of hepatitis B are similar to hepatitis A. There is however no history of fever and the onset is more gradual. After the infection there is chronic liver disease which may progress to cancer of the liver. Prevention and Control: There is no specific treatment for hepatitis B.
However the following preventive measures may be helpful: (i) Avoid blood transfusion and its products which are contaminated with hepatitis B virus. (ii) Use disposable needles and syringes and always use sterilized instruments for piercing ear or nose or for tattooing. (iii) Give hepatitis B vaccine by intramuscular route. This vaccine is effective in 95 percent cases and is given in 3 doses of one ml each. The second dose is given one month after the first dose and the third dose is given 5 months after the second dose. (iv) Hepatitis B immunoglobulin (HBIg) should be given immediately to the persons who are exposed to hepatitis B virus – positive blood e.g. doctors, nurses and attendants engaged in blood transfusion and dialysis work.
To be effective HBIg should be given within 24 hours after exposure. It produces passive immunity and provides protection for about three months. The simultaneous use of hepatitis B vaccine and HBIg is considered superior to the use of HBIg alone.