delta agent

hepatitis D virus

a small "defective" RNA virus, similar to viroids and virusoids, that requires the presence of hepatitis B virus for replication. The clinical course is variable but is usually more severe than other hepatitides. Synonym(s): delta agent, delta antigen, delta virus, hepatitis delta virus

hep·a·ti·tis D vi·rus

, hepatitis delta virus (HDV) (hep'ă-tī-tis vī'rŭs, del'tă) A small "defective" RNA virus that requires the presence of hepatitis B virus for replication. The clinical course is variable but is usually more severe than other hepatitides.
Synonym(s): delta agent.