Question
Enumerate enterically transmitted hepatitis viruses.
Answer
The enterically transmitted hepatitis viruses — transmitted by the faecal-oral route, causing acute (self-limiting) hepatitis without progression to chronic liver disease, in contrast to the parenterally-transmitted hepatitis viruses (B, C, D):
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Hepatitis A virus (HAV) — a picornavirus, transmitted via contaminated food/water or person-to-person contact, particularly common in areas of poor sanitation; causes acute hepatitis, generally self-limiting with lifelong immunity after recovery; a safe and effective vaccine is available.
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Hepatitis E virus (HEV) — a hepevirus, similarly transmitted via faecal-oral route (notably via contaminated water in outbreaks); generally self-limiting like HAV, but carries a markedly increased risk of fulminant hepatic failure and mortality in pregnant women (particularly in the third trimester), a distinguishing and clinically important feature compared to HAV.
Shared features: both are non-enveloped RNA viruses, resistant to environmental degradation, excreted in stool, and do NOT cause chronic hepatitis or a carrier state (unlike hepatitis B and C) — recovery is followed by lifelong immunity to that specific virus.