Global epidemiology and medical aspects of hepatitis E.

Hepatitis E is a self-limited enterically transmitted acute viral hepatitis that occurs frequently in epidemic outbreaks and as sporadic hepatitis in the Indian sub-continent, Southeast and Central Asia, the Middle East, parts of Africa, and Mexico. Hepatitis E virus (HEV) is excreted in faeces and is transmitted predominantly by the faecal-oral route, usually through contaminated water. The reservoir of the virus during the inter-epidemic periods in disease-endemic countries may reside in the environment, in sub-clinically HEV-infected humans, and/or animals infected with an HEV-like virus. Chronic infection is unknown. Diagnosis of HEV infection is usually made by detection of anti-HEV antibodies or HEV-RNA in patients serum specimens. Clinical illness due to HEV infection is similar to other forms of viral hepatitis except in pregnant women, in whom the illness is particularly severe with a mortality as high as 25%. Asymptomatic and anicteric infections may occur. No specific treatment is available, and the most effective mode of preventing this disease is use of clean water and proper sanitation. Recombinant vaccines are being developed that may be particularly useful for travellers to the disease-endemic areas and for pregnant women.