Purification and biochemical characterization of chicken anaemia agent

Chicken anaemia agent (CAA) was purified using differential centrifugation and successive cycles of equilibrium density gradient centrifugation using sucrose and CsCl. The purification method was dependent on the use of an antigen-detecting ELISA based on a CAA-specific monoclonal antibody. Virus particles banded at a density of 1.33 to 1.34 g/ml in CsCl and measured 23.5 +/- 0.8 nm in diameter. Purified preparations contained one major polypeptide (Mr 50,000) and a single-stranded, circular DNA (2.3 kb). CAA shares some of the biochemical characteristics possessed by porcine circovirus and the virus associated with psittacine beak and feather disease.