Defective hepatitis virus is ?

Ans. is 'd' i.e., HDV Hepatitis D (HDV) or Delta virus It is defective RNA virus dependent on the helper function of HBV for its replication and expression. It contains single stranded RNA (ssRNA) - Defective RNA. It has no independent existence and can survive and replicate only as long as HBV infection persists in the host. It resembles some plant viruses, such as viroids or satellite viruses. It has been classified in genus Deltavirus. Delta core of HDV is encapsidated by an outer envelope of HBs Ag, so it require cooperative function of HBV. Intracellular replication of HDV RNA can occur without HBV but liver injury requires the presence of HBV. HDV can cause two types of infection.