Pathological changes in bursa of Fabricius in concurrent infections of infectious bursal disease with Newcastle disease, Escherichia coli infection and aflatoxicosis

Concurrent infections of infectious bursal disease (IBD) with Newcastle Disease (ND), Escherichia coli infection and aflatoxicosis were studied in five-week-old White Leghorn chicken sequentially. The bursa to bodyweight ratio revealed an early enlargement of bursa of Fabricius (BF) followed by the atrophy of BF in all the three concurrent infections groups with advanced onset of atrophic changes in concurrent infections groups compared to that of IBD infection alone. Histologically, in IBD-ND concurrent infection group, the BF showed very prominent proliferation of lymphoblasts in the follicles at 24 hours post infection (HPI) with increased fibroplasia in the inter follicular areas at 120 HPI. While in IBD-E. coli concurrent infection group, BF revealed prominent lymphoid depletion in the medulla of follicles from 12 HPI to 24 HPI and the interfollicular fibroplasia was observed as early as 72 HPI. In IBD with aflatoxicosis group the BF revealed changes similar to that of IBD group initially and later atrophy started as early as 144 HPI with cystic and glandular transformation of bursal follicles and increased interfollicular fibrosis.