Since its chance discovery a mere decade ago, the delta agent has been characterized as a novel pathogen that poses the risk of developing into a scourge of modern times. With its unique single-stranded
circular RNA, exclusive dependence on HBV for its replication, and characteristic ability to suppress
hepatitis B synthesis, the delta agent has emerged as an important global cause of
fulminant hepatitis and progressive
liver disease. Persons at greatest risk of
delta infection are those living in endemic areas and
HBsAg-carrier parenteral drug abusers, hemophiliacs,
hemodialysis patients, and homosexual men in nonendemic areas. Widespread dissemination appears possible. There is as yet no known effective treatment for established
delta infection, and, for the present, clinicians must concentrate on preventing HDV
infection by incorporating vigorous use of the
hepatitis B vaccine into strategies for preventing HBV
infection.