Virology of Hepatitis D Virus

Although much of the current understanding of the replication of hepatitis D virus (HDV) has been gained from ex vivo rather than in vivo studies, many seemingly unique aspects have been discovered. These include the ultra-small size and circular conformation of the RNA genome, the presence on the viral RNAs of two ribozymes, the role of RNA-directed RNA transcription by redirection of host enzymes, the requirement of site-specific, posttranscriptional RNA-editing, and more. This review addresses recent insights, remaining controversies, and just plain deficits in our understanding of HDV replication.