Analysis of Aleutian disease of mink parvovirus infection using strand-specific hybridization probes

A 7- to 95-map unit segment of DNA from Aleutian disease of mink parvovirus (ADV) was subcloned into a bacteriophage SP6 based transcription vector and used to produce radiolabeled viral RNA transcripts corresponding to either 'plus' or 'minus' sense. The radiolabeled transcripts were reacted against Southern blots of whole cell DNA from ADV infected cell cultures as hybridization probes. The 'plus' sense RNA probe hybridized both to duplex replicative forms (RFs) as well as to single-stranded virion DNA (SS DNA), which is 'minus' in sense. In contrast, the 'minus' sense RNA probe reacted preferentially with the duplex RFs. When these probes were tested against DNA extracted from mink infected with the virulent ADV-Utah I strain, RFs were detected at 10 days after infection in mesenteric lymph node, liver, spleen and gut, but only in gut and mesenteric lymph node at 43 days. SS DNA was noted in these tissues at 10, 43 and 60 days, and was more abundant than RFs. Only SS DNA at very low levels was observed in bone marrow cells. Serum contained large amounts of SS DNA (probably in virions) at 10 days, less at 43 days, and no detectable DNA at 60 days. These findings suggest that ADV replication may have occurred in the gut as well as lymphoreticular tissues, and that bone marrow was not a major site of ADV replication.