Hepatitis, a broad term for inflammation of the liver, has a number of infectious and non-infectious causes. Two of the viruses that cause hepatitis (hepatitis A and E) can be transmitted through water and food; hygiene is therefore important in their control.
The disease and how it affects people
Among the infectious causes, hepatitis A and hepatitis E are associated with inadequate water supplies and poor sanitation and hygiene, leading to infection and inflammation of the liver. The illness starts with an abrupt onset of fever, body weakness, loss of appetite, nausea and abdominal discomfort, followed by jaundice within a few days. The disease may range from mild (lasting 1-2 weeks) to severe disabling disease (lasting several months). In areas highly endemic for hepatitis A, most infections occur during early childhood. The majority of cases may not show any symptoms; fatal cases due to fulminant acute hepatitis are rare. Nearly all patients recover completely with no long-term effects.
Hepatitis A and E viruses, while unrelated to one another, are both transmitted via the faecal-oral route, most often through contaminated water and from person to person. Hepatitis A could also be transmitted via food contaminated by infected food-handlers, uncooked foods, or foods handled after cooking. Hepatitis A has also caused outbreaks transmitted through injecting or non-injecting drug use.
Both hepatitis A and E are found worldwide. Hepatitis A is particularly frequent in countries with poor sanitary and hygienic conditions (in Africa, Asia, and Central and South America). Countries with economies in transition and some regions of industrialized countries where sanitary conditions are sub-standard are also highly affected, e.g.in southern and eastern Europe and some parts of the Middle East. Outbreaks of hepatitis E have occurred in Algeria, Bangladesh, China, Ethiopia, Indonesia, Iran, Libya, Mexico, Myanmar, Nepal, Pakistan, Somalia, and the Central Asian republics of the CIS.
Scope of the Problem
The mortality rate is low (0.2% of icteric cases) and the disease ultimately resolves. Occasionally, extensive necrosis of the liver occurs during the first 6-8 weeks of illness. In such cases, high fever, marked abdominal pain, vomiting, jaundice, and hepatic encephalopathy (with coma and seizures) are the signs of fulminant hepatitis, leading to death in 70-90% of the patients. In these cases mortality is highly correlated with increasing age, and survival is uncommon over 50 years of age. Among patients with chronic hepatitis B or C or underlying liver disease, who are superinfected with hepatitis A virus, the mortality rate increases considerably.
Improved economic and sanitary conditions may lead to a higher disease incidence in older age groups, with higher reported rates of clinically evident hepatitis A. In countries with very low hepatitis A infection rates, the disease may occur among specific risk groups such as travellers. Hepatitis E is mainly found in young to middle-aged adults. Women in the third trimester of pregnancy are especially susceptible to acute fulminant hepatitis arising from hepatitis E infection.
As there are no specific antiviral drugs against hepatitis A and E, prevention of these viral diseases remains the most important weapon for their control, such as:
- Providing education on good sanitation and personal hygiene, especially hand-washing
- Adequate and clean water supplies and proper waste disposal
- Vaccination against hepatitis A for persons at risk, e.g. travellers visiting areas where the disease is common.
Prepared for World Water Day 2001. Reviewed by staff and experts from the cluster on Communicable Diseases (CDS) and the Water, Sanitation and Health unit (WSH), World Health Organization (WHO).