Defective hepatitis virus is -

Ans. is 'd' i.e., HDV Hepatitis D (HDV) or Delta viruso It is defective RNA virus dependent on the helper function of HBV for its replication and expression,o It contains single stranded RNA (ssRNA) - Defective RNA.o It has no independent existence and can survive and replicate only as long as HBV infection persists in the host,o It resembles some plant viruses, such as viroids or satellite viruses.o It has been classified in genus Delta virus.o Delta core of HDV is encapsidated by an outer envelope of HBs Ag, so it require cooperative function of HBV.o Intracellular replication of HDV RNA can occur without HBV but liver injury requires the presence of HBV.o HDV can cause two types of infection.HDV infectionSuperinfectiono In patient already infected with HBVo Has grave course with more chances of fulminant hepatitis and chronic infectiono Ig M anti HDV (+)ve and Ig M anti HBc (+)veCoinfectiono Infection occurs simultaneously with HBVo Comparatively mild course.o Ig M anti HDV (+)ve and ig G anti HBc (+)veo There is no association between HDV and hepatocellular carcinoma.o HDV antigen (Delta antigen) is primarily expressed in liver cell nuclei, where it can be demonstrated by immunofluorescence.