1998 Volume 51 Issue 2 Pages 65-69
To reproduce the swollen head syndrome (SHS), avian reovirus (ARV) and Escherichia coli (E. coli) were inoculated into chickens with immunosuppression induced by infectious bursa' disease virus (IBDV). Groups of 8 to 9 SPF chickens were inoculated orally with IBDV at 1 week of age and then with ARV at 3 weeks of age by eye drop (instillation), followed by inoculation with E. coli at days 1, 4 and 7 postinoculation of ARV. At autopsy made on 20 days postinoculation of E. coli, although none of the chickens showed clinical signs of SHS, inflammatory and granulomatous lesions were found in the air spaces and middle ears in 2/9, 4/9 and 1/8 chickens. Eight other groups (A-H: 13 to 14 chickens each) were inoculated as follows and autopsied at 4 to 20 days postinoculation of E. coli; group A (uninoculated cotrol), B (E. coli), C (ARV), D (ARV +E. coli), E (IBDV), F (IBDV+E. coli), G (IBDV+ARV), and H (IBDV+ARV+E.coli). Slight swelling of the eyelid was seen in 2 and 3 chickens of groups B and H, respectively. Histologically, the head lesions including slight inflammatory reactions were observed in 3, 2, 1, 2 and 5 chickens in groups B, D, F, G and H, respectively. Subcutaneous cellulitis in the head was observed only 2 and 4 chickens in groups B and H, repectively.