A RETROSPECTIVE IMMUNOHISTOCHEMICAL STUDY OF TYPE-II AVIAN ADENOVIRAL INFECTION IN TURKEY, PHEASANT, AND CHICKEN TISSUES

A retrospective study of avian cases submitted to the Michigan Animal Health Diagnostic Laboratory between 1986 and 1992 produced four pheasant, five turkey, and five chicken cases in which splenic tissue was positive for type II adenoviral antigen using an agar gel immunodiffusion assay. Tissue sections from these cases were evaluated microscopically using both routine hematoxylin and eosin (H&E) staining and an immunohistochemical staining technique for type II adenoviral antigen. Tissues from all four pheasant cases and four of five turkey cases, but none of the five chicken cases, stained positively by histochemistry. Five additional chicken cases, obtained from the U.S. Department of Agriculture Eastern Laboratory of the Food Safety Inspection Service, had splenic lesions of undetermined etiology; these were also evaluated. One of the five cases had splenic inclusions on H&E staining and had strong positive histochemical staining. The immunohistochemical staining technique was sufficiently sensitive for use on diagnostic tissues that have been routinely fixed in formalin and processed for histopathology, and it detected all three recognized type II adenoviruses,