title: Immunosuppressive effect of a naturally acquired subclinical bursal agent infection on vaccination against Newcastle disease.
abstract: A naturally acquired subclinical infection of infectious bursal agent was shown to be the probable causative factor of marked immunosuppression of Newcastle disease vaccine in young chicks. Old hens maintained in the same contaminated environment did not exhibit immunosuppression.
mesh_terms: D000367:Age Factors; D000818:Animals; D000917:Antibody Formation; D002645:Chickens / Q000276:immunology*; D007165:Immunosuppression Therapy; D007243:Infectious bursal disease virus / Q000276:immunology; D009522:Newcastle disease virus / Q000276:immunology*; D011201:Poultry Diseases / Q000276:immunology*; D012088:Reoviridae Infections / Q000276:immunology / Q000662:veterinary*; D014611:Vaccination / Q000662:veterinary*