Presence of fowl parvovirus in fibroblast cell cultures prepared from uninoculated White Leghorn chicken embryos.

Chicken embryo fibroblast cell cultures prepared from commercial uninoculated White Leghorn eggs showed a spontaneous degeneration. Upon staining with haematoxylin-eosin intranuclear inclusion bodies of Cowdry type A were seen. Also, nuclear fluorescence was detected after indirect immunofluorescence staining with anti-serum to fowl parvovirus strain ABU. Electron microscopy of thin sections revealed parvovirus-like particles in both the nucleus and cytoplasm of the affected cells. During purification the viral particles banded in CsCl at a density of 1.42 to 1.43 g/ml and displayed typical parvovirus morphology by negative-staining EM. The viral particles contained single-stranded DNA of one polarity with a natural primer at the 3'-end of the molecules. All these properties are characteristic of self-replicating fowl parvovirus strongly suggesting its transovarial transmission.