FAILURE OF MATERNAL ANTIBODIES TO PROTECT YOUNG TURKEY POULTS AGAINSTCHALLENGE WITH TURKEY RHINOTRACHEITIS VIRUS

Groups of turkey poults with high levels of maternal antibodies (MA+) to turkey rhinotracheitis virus (TRTV) were challenged with virulent T RTV at 1, 5, and 10 days of age. A maternal antibody-free group (MA-) was also challenged at 1 day of age. Before each challenge, levels of maternal antibodies to TRTV were measured by enzyme-linked immunosorbe nt assay. Clinical signs were scored for each group. Unchallenged poul ts showed no signs. Respiratory signs in poults infected at 10 days of age resembled those seen in MA- birds infected at 1 day of age but bo th were more severe than in MA+ birds infected at 1 day of age, when t he maternal antibodies were highest. However, overall, the presence of high levels of maternal antibodies did not prevent the development of clinical disease.