Hepatitis E

Excerpt

Hepatitis E virus (HEV) is the leading cause of acute viral hepatitis worldwide. However, its diagnosis is often overlooked due to its nonspecific symptoms and typically self-limited course. HEV belongs to the genus Orthohepevirus of the Hepeviridae family. This virus is a nonenveloped, icosahedral, with a single-stranded positive-sense ribonucleic acid genome measuring approximately 27 to 34 nm in diameter.

HEV is mainly transmitted via the fecal-oral route and usually causes acute, self-limited hepatitis in immunocompetent individuals. However, chronic hepatitis has been reported in immunosuppressed individuals. Compared to hepatitis A virus (HAV), which also spreads via the enteric route, HEV infection has a higher mortality, particularly among high-risk groups such as pregnant women, recipients of solid organ transplants, and individuals who are immunocompromised.

The first evidence of an enterically transmitted viral hepatitis distinct from HAV emerged from a waterborne hepatitis epidemic in the late 1970s in Kashmir, India. Dr Mohammad Sultan Khuroo, an Indian gastroenterologist, helped identify this new form of hepatitis by demonstrating that affected patients lacked serological markers of acute hepatitis A, suggesting an unknown viral agent. In 1983, Mikhail S Balayan, a Russian virologist, and his colleagues confirmed the existence of HEV through self-experimentation, in which he ingested a stool extract from an infected patient and developed the disease. This experiment led to the identification of HEV as an enterically transmitted virus. NANBH (non-A, non-B hepatitis) was later named Hepatitis E to align with the established nomenclature.