The role of maternal antibodies in preventing infectious bursal disease (IBD, Gumboro disease) during the first weeks of age of chicks
1991
Iordanidis, I.P. | Artopios, V.E. (Aristotelion Univ., Thessaloniki (Greece). Faculty of Veterinary Medicine. Pathological Clinic of Poultry) | Koumpati, M. (Aristotelion Univ., Thessaloniki (Greece). Faculty of Veterinary Medicine. Laboratory of Microbiology and Infections Diseases)
One-day-old chicks with precipitating IBD antibodies were used and divided into three groups(A, B, C) of 16. On the first day of age chicks of group A were infected with a pathogenic strain of IBD virus. On the 24th day serum samples from all groups were taken and the chicks of group A were reinfected, the chicks of group B infected for the first time with the same pathogenic strain as in group A, whereas the chicks of group C remained uninfected. All sera tested by immunodifusion were positive without significant differences among them. On the 33th day serum samples were taken again and eight chicks from each group were slaughtered. Before slaughtering the chicks were weighed. The weight of spleen and bursa of Fabricious of each chick was also measured.The sera of chicks of groups A and B were positive, whereas those of group A and B chicks were smaller than those of group C chicks (mean 0.27, 0.38 and 1.11 g respectively). On the 38th day the remaining eight chicks of group C were infected and after seven days were slaughtered and examined macroscopically. Swelling and oedema were observed in the bursae of all chicks. On the 52nd day all the remaining chicks of groups A and B were slaughtered and examined as the chicks on the 33rd day. All tested sera were strongly positive and the bursae of group A chicks were smaller than those of group B (mean 0.78 and 0.87g respectively). It is concluded that maternal antibodies which last until approximately the 30th day can protect chicks from clinical disease, when they are infected either on the first or on the 24th day of age. While maternal antibodies prevent typical lesions in the bursa (swelling) of infected chicks do not prevent hypoplasia, which lasts up to the end of the rearing period. The level of maternal immunity has to be taken into account in drawing of vaccination programmes.
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