Elevated concentrations in serum immunoglobulins due to infection by ovine progressive pneumonia virus.

Sixty-seven serum samples were obtained from 2 sheep flocks. Agar gel immunodiffusion (AGID) was used to separate progressive pneumonia virus (PPV)-infected sheep from noninfected sheep by the presence of precipitating antibodies. Immunoglobulin (Ig), total protein, and albumin concentrations were then measured from all 67 sera to determine whether differences existed between PPV-infected and non-infected sheep. A significant difference (P less than 0.0005) was found in both total protein and Ig concentration between PPV-infected and noninfected sheep. This corresponding difference was absent in albumin measurements. The significant differences (P less than 0.0005) in Ig and total protein concentrations were then used to evaluate a field test for diagnosing progressive pneumonia. The possibility of using either total protein or Ig concentrations as a field test was found to be highly unlikely due to variation in individual values.