CHARACTERIZATION OF INFECTIOUS BURSAL DISEASE IN THE BURSECTOMIZED AND THYMECTOMIZED CHICKEN

Infectious bursal disease was characterized clinically, haematological ly, immunologically and pathologically in bursectomized (Gr BXV) and t hymectomized (Gr TXV) White Leghorn chicken infected with IBDV by naso -ocular route. Clinicopathologically, disease was subclinical to mild in nature while haematological features were similar to those of intac t birds with thymus or bursa. On necropsy examination chickens of Gr B XV showed emaciation, empty crop atrophy of thymus, spleen, and kidney s on DPI-3 and 7 as compared to Gr BXC. The chicken of Gr TXV showed e maciation, empty crop, atrophied bursae, spleen and enlarged and hyper trophied liver after infection was compared to Gr TXC. Histopathologic al examination of various tissues of chicken of Gr BXV showed mild pat hoanatomical alterations. Thymus revealed mild oedema and presence of blast-like cells. Kidneys showed hyperaemia, sub-capsular haemorrhages , and pronounced hydronephrosis due to post-surgical complications in a few birds. Chicken of Gr BXV as well as TXV failed to show detection of IBD antigen by AGPT, while specific weak fluoresence was seen in c ertain organs by IF test. Chicken of later group showed marked bursal atrophy and pronounced histological alterations. Bursal changes were c omprised follicular atrophy, depiction of lymphoid cells and presence of larger cysts in medulla and cortex of bursal follicles with atrophy of cortex. Serum immunoglobulins S-IgG and S-IgA values increased on DPI-3 and 7 while S-IgM decreased on DPI-3 and 7 in Gr TXV as compared to Gr TXC while these values revealed varying trends in chicken of Gr BXV than Gr BXC. The S-IgG values increased on DPI-3 and 7, IgM incre ased on DPI-3 and decreased on DPI-7 while S-IgA decreased on DPI-3 an d 7. It may be concluded that manifestations of IBD was mild in bursec tomized as well as in thymectomized chicken.