Summary The recently described monomer covalently closed linear replicative form DNA (Mccl RF DNA) of Aleutian disease parvovirus (ADV) is an infectious intermediate of the viral DNA replication cycle. Transfection of highly purified Mccl RF DNA into susceptible feline kidney cells (CCC clone 81 cells) resulted in viral DNA replication, expression of viral proteins and synthesis of infectious progeny virus. Mccl RF DNAs generated under permissive (32 °C) or non‐permissive (37 °C) conditions were shown to be biologically indistinguishable. The accumulation of the Mccl RF DNA form at the non‐permissive temperature in vitro strongly resembles that in bone marrow cells of naturally infected mink and may reflect one mechanism contributing to virus persistence of ADV in vivo. Zusammenfassung Die monomer kovalent‐geschlossene lineare replikative Form (Mccl RF)‐DNA des Aleutian Disease Parvovirus (ADV) ist ein infektiöses Intermediat im Rahmen der viralen DNA‐Replikation. Transfektion hochgereinigter Mccl RF DNA in feline Nierenzellen CCC clone 81 induzierte virale DNA‐Replikation, die Expression viraler Proteine und die Synthese infektiöser Virionen. Mccl RF DNAs aus infizierten Zellen inkubiert unter permissiven (32 °C) oder nicht‐permissiven (37 °C) Bedingungen waren funktionell nicht unterscheidbar. Die relative Anhäufung dieser RF‐DNA‐Form unter der nicht‐permissiven Temperatur in vitro ähnelt stark der in Knochenmarkszellen infizierter Nerze in vivo, und ist möglicherweise eine Ursache der Viruspersistenz im Rahmen der Aleutenkrankheit der Nerze.

Summary. A hog cholera virus (HCV)-specific genetic probe has been generated after cloning of the genomic viral RNA. This probe distinguished between HCV and the closely related bovine viral diarrhoea virus (BVDV). Furthermore, it detected a broad spectrum of HCV strains and isolates which differ in their phenotype such as virulence.