Immune dysfunction following experimental Newcastle and infectious bursal disease in broilers

Immune status in birds following Newcastle disease (ND) and infectious bursal disease (IBD) was evaluated by assay of delayed hypersensitivity to 2, 4-dinitrochlorobenzene (DNCB) and antibody titres against Brucella abortus plain antigen. Primary sensitization with DNCB on 14 day post-infection (dpi) was followed by a challenge on 21 dpi. The mean skin fold thickness at 24 h post-treatment was significantly (P<0.05) lower in NO recovered birds as compared with the birds recovered from IBD. The skin reaction was typical of delayed hypersensitivity in IBD recovered birds. The mean antibody titres to B. abortus on 28 dpi were significantly (P<0.05) lower in IBD recovered birds as against near nonnal titres in ND recovered birds. The results suggested irreversible suppression of cell mediated immune response in ND recovered birds whereas the same was slightly elevated in IBD. The humoral immune responses were found to be vice-versa.