[Viral hepatitis E]

Thanks to progress in serologic techniques evidence was obtained in 1980 showing that acute hepatitis epidemics observed in India were due to neither virus A nor virus B. The presence of another virus was confirmed and its genome was cloned and sequenced in 1991. Hepatitis virus E is a small RNA virus that differs from other known human viruses. Man and probably a few animal species maintain dissemination by the fecal route. Subjects not previously contaminated are susceptible and produce protective antibodies. Contamination occurs by the fecal-oral route general from water or tainted food. Direct contamination is rare. Vertical transmission from mother to fetus can also be observed. Outbreaks of the disease are characterized by epidemic proportions, preferential involvement of adolescent and young adults, and high incidence of fulminant cases especially in pregnant women. Outbreaks have been observed in endemic settings in southern Asia, Africa, and Mexico where sporadic cases are observed. Endemic areas are found in all developing countries. Hepatitis E is not clinically different from other acute viral hepatitis. Asymptomatic forms are common especially in children. The course of the disease is usually benign with little risk of development of chronic symptoms and cirrhosis. However hepatitis E is associated with a high incidence of severe cases with a mortality of 1 to 2% from icteric forms which occur in 15 to 20% of cases involving women contaminated during the last three months of pregnancy. Diagnosis can be made using either synthetic proteins or recombinant peptides. for the epitopes of the virus. Prevention depends on protection of the water supply and proper sewage disposal. Successful active immunization of monkeys holds promise for development of a vaccine. Due to its magnitude and high mortality rate hepatitis E is a major health problem for numerous regions around the world including Southeast Asia.