Also called hepatitis delta virus.
RNA virus is replication defective and can cause infection only when it is encapsulated by HBsAg.
It is dependent on the genetic information from HBV for its multiplication and causes hepatitis only in the presence of HBV.
Occurs with acute coinfection with HBV, with the latter established first to provide the HBsAg needed for development of complete hepatitis D virions.
Can occur as a super infection of a chronic carrier of HBV with a new inoculum of HDV and results in disease 30-50 days later.
The coinfection with HBV results in hepatitis process that ranges from mild to fulminant disease.
Fulminant disease is more likely with coinfection of D and B hepatitis than with HBV alone.