Extrahepatic replication of woodchuck hepatitis virus in chronic infection

We describe studies of woodchuck hepatitis virus nucleic acids in liver and other tissues of chronically infected woodchucks, using Southern and Northern blot hybridization techniques. Single-stranded and covalently closed circular replicative DNA molecules were distinguished from partly double-stranded virus genomes. In most animals the liver contained more virus than any other organ, but all extrahepatic organs studied (spleen, thymus, pancreas, and kidney) contained viral DNA and significant amounts of viral RNA. In the spleen, partly double-stranded virus genomes were present at higher levels than in any other organ but liver, but nonetheless replicative intermediates were not detected. The observation of RNA transcripts in the absence of detectable covalently closed circular DNA template suggests that a small proportion of cells in extrahepatic tissues are infected with WHV.