Assuntos
Pneumonia Intersticial Progressiva dos Ovinos/epidemiologia , Fatores Etários , Animais , Anticorpos Antivirais/biossíntese , Feminino , North Dakota , Pneumonia Intersticial Progressiva dos Ovinos/imunologia , Pneumonia Intersticial Progressiva dos Ovinos/prevenção & controle , Ovinos , Vírus Visna-Maedi/imunologiaRESUMO
Various cell cultures were evaluated for their ability to support progressive pneumonia virus infection in vitro. Ovine trachea cells supported progressive pneumonia virus infection for an extended time,were extremely durable and could be passaged up until 30 passages. Progressive pneumonia virus infected ovine trachea cells were then used for the production of antigen for agar-gel immunodiffusion. A method for concentrating antigen, diafiltration, was compared to dialysis against polyethylene glycol. Using diafiltration, the concentrated virus was easily quantitated, less viscous (and therefore easier to apply) and only produced one precipitation line. Agar-gel immunodiffusion was used to survey 401 animals from two sheep flocks. One flock (96 sheep) was free of progressive pneumonia while the other flock had 111 of 305 total animals positive for precipitating antibodies. The incidence of precipitating antibodies in sheep ranged from 23% for yearling ewes to 80% in ewes seven years old.
Assuntos
Anticorpos Antivirais/análise , Imunodifusão , Pneumonia Intersticial Progressiva dos Ovinos/imunologia , Vírus Visna-Maedi/imunologia , Fatores Etários , Animais , Antígenos Virais/isolamento & purificação , Bovinos , Células Cultivadas , Feminino , Ovinos , Traqueia , Replicação ViralRESUMO
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.
