What is hepatitis A? Where does it occur?
Hepatitis A is an acute inflammation of the liver caused by a virus known as the ‘hepatitis A virus’ (HAV). It is more common in countries with poor sanitation and unsafe water. There are two patterns of HAV infection depending on the region:
- In the developing world, HAV has high or intermediate prevalence, and most of the children have been infected by the age of 10 years. Hepatitis A infection in children produces very mild symptoms or may even remain subclinical. Since a single-time infection with HAV leads to life-long immunity, these children become immune to HAV and thus do not get HAV infection during adulthood.
- In developed countries, where HAV has low prevalence, the children are not exposed to this virus when young. So hepatitis A occurs occasionally in outbreaks and may affect adults also and it may produce severe symptoms.
How is hepatitis A transmitted?
HAV spreads by the faecal–oral route. This infection is more common in places of poor sanitation and overcrowding. The outbreaks of hepatitis are usually food-borne. Ingestion of street food prepared in polluted water leads to high chances of HAV infection. Infected individuals have the potential to spread infection to others prior to onset of their own symptoms. This period of silent infectivity lasts roughly for 10 days following infection. The undeveloped and developing countries have poor hygiene standards and the rates of infection with HAV are high, so the infection is usually contracted during childhood. With rising incomes the hygienic standards improve and access to clean water increases. Hence, the incidence of HAV decreases and is usually seen in older individuals.
What is the meaning of ‘faecal–oral route’ in context of transmission of hepatitis A?
The diagram given below shows how germs from faeces spread via fluids, fingers, flies and fields.
- Fluids: Germs from faeces on the ground can get into the water (fluids). This water when consumed may lead to infection. This can also occur when the old damaged water pipes get contaminated by nearby damaged sewer pipe.
- Fingers: Fingers or hands that have not been washed properly after going to the toilet can transmit the germs to foods that are then eaten.
- Flies: Flies and other insects can transfer germs from faeces to food. So it is very important to keep flies and other bugs out of the kitchen and dining area.
- Fields: Germs from faeces can also seep into fields, crops and other sources of food if faeces are not disposed of properly. To prevent field contamination, it is important that more and more modern toilets are constructed and open defecation is stopped.
What are the signs and symptoms of hepatitis A?
Many patients, especially children, may exhibit no symptoms at all. In those patients who do show symptoms, the symptoms of hepatitis A in early stages are similar to those of flu. The time between infection and symptoms (incubation period) is 2–6 weeks with an average of 4 weeks.
Symptoms usually last less than 8 weeks and include fever, fatigue, loss of appetite, nausea,
jaundice, dark-coloured urine, light- or clay-coloured stool and abdominal discomfort.
How does the age of patient affect his or her symptoms?
The risk of developing symptoms is related to age. Young children typically suffer from a milder form of hepatitis A, usually lasting about 1–3 weeks, whereas adults generally suffer a much more severe form of the disease. In India, most of the adults have already had HAV infection during childhood, so are immune from having HAV infection again during adulthood.
How is hepatitis A diagnosed?
Clinically hepatitis A is similar to other types of acute viral hepatitis. In adults, the predominant symptom of acute viral hepatitis due to HAV is jaundice (yellowness of eyes and urine) which is usually preceded by nausea, vomiting, malaise, fever and loss of appetite (prodromal symptoms). Blood tests will reveal very high liver enzymes(aspartate aminotransferase [AST] or serum glutamic-oxaloacetic transaminase [SGOT] and alanine transaminase [ALT] or serum glutamic pyruvic transaminase [SGPT] . 10 3 upper limit of normal) and elevated bilirubin levels, indicating jaundice. Detection of HAV-specific immunoglobulin M (IgM) antibodies in the blood confirms the diagnosis of hepatitis A.
How is hepatitis A treated?
Treatment of hepatitis A depends on symptoms and severity of the infection. For mild symptoms, no treatment is required and symptoms begin to resolve within few days. If symptoms are bothersome, your doctor may prescribe symptomatic medication. The treatment is aimed at maintaining adequate nutritional and fluid balance. The fluid that is lost from vomiting and diarrhoea needs to be replaced. Self-medication is not advisable and may even be harmful. Recovery may be slow and may take 1 or 2 months. For severe acute viral hepatitis that is progressing to liver failure, hospitalization is needed.
Self-medication is not advisable and may even be harmful.
What are the complications of hepatitis A?
Some patients may develop prolonged period of jaundice (cholestatic hepatitis). These patients may benefit from specific drug therapy. Rarely a patient may develop acute liver failure (unconsciousness or bleeding tendency following an episode of jaundice). The risk of death from
acute liver failure due to hepatitis A increases with age. The mortality risk is also high if a person has underlying chronic liver disease (cirrhosis). Liver transplantation may be required in these patients.
How can we prevent hepatitis A?
There are two aspects to prevention of HAV infection:
- Hygiene and sanitation: Safe drinking water, good sanitation and proper hygiene are most important measures to ensure good health and prevent hepatitis A. Sanitation is essential for prevention of
human contact with the hazards of wastes. Treatment and proper disposal of sewage or waste water is also important.
- Vaccination: Injectable HAV vaccine is also available. It is recommended for individuals in an endemic region and in the travellers from developed countries who are visiting an endemic country. An initial dose provides protection after 2–4 weeks of vaccination; the second booster dose is given 6–12 months later.