title: [Delta agent].
abstract: Discovered in 1977 by Rizetto and his collaborators, agent delta is today considered as a virus entirely distinct from the H/B virus. This small RNA virus, transmissible to primate and to man, is defective: its replication in the liver is only possible when there is a pre-existing or simultaneous infection by the H/B virus with HBs antigenaemia. Its clinical importance appears very great as agent delta is very pathogenic to the liver: super-infection by this virus of a patient infected by the H/B virus explains a good number of cases of acute fulminant hepatitis and of chronic active hepatitis developing towards cirrhosis, disorders attributed in the past solely to the hepatitis B virus.
mesh_terms: D000818:Animals; D006509:Hepatitis B / Q000150:complications* / Q000276:immunology / Q000382:microbiology; D006514:Hepatitis B Surface Antigens / Q000302:isolation & purification; D003699:Hepatitis D / Q000150:complications*; D003698:Hepatitis Delta Virus / Q000472:pathogenicity*; D006521:Hepatitis, Chronic / Q000382:microbiology; D006801:Humans
chemical_list: D006514:Hepatitis B Surface Antigens
vernacular_title: L'agent delta.