Hepatitis E is caused by the hepatitis E virus (HEV), the major etiologic agent of enterically transmitted non-A
hepatitis worldwide. HEV is responsible for major outbreaks of acute
hepatitis in developing countries, especially in many parts of Africa and Asia. The HEV is a spherical, non-enveloped, single-stranded, positive sense RNA virus that is approximately 32 nm to 34 nm in diameter and is the only member in the family Hepeviridae and genus Hepevirus. There are four distinct genotypes of HEV (genotypes 1-4). While genotype 1 is predominantly associated with large epidemics in developing countries, genotype 3 has recently emerged as a significant pathogen in developed countries. The clinical manifestations and the laboratory abnormalities of
hepatitis E are not distinguishable from that caused by other hepatitis viruses. However, high mortality among pregnant women particularly during the third trimester distinguishes HEV from other causes of acute viral
hepatitis. Specific etiologic diagnosis among infected cases can be made by serological testing or detection of viral
nucleic acid by reverse transcription polymerase chain reaction. Although there are
vaccine candidates that had been shown to be safe and efficacious in clinical trials, none are approved currently for use. There is no specific
therapy for acute
hepatitis E as treatment remains supportive.