Hepatitis D virus (HDV) is an example of a replication defective, helper dependent ssRNA virus because it requires Hepatitis B virus (HBV) to provide HBV surface antigen (HBsAg) for the encapsidation of its genome.
The Hepatitis D virus (HDV) is a defective virus that requires the Hepatitis B virus (HBV) to package its genetic material, specifically providing its surface antigen (HBsAg).