Subclinical Infectious Bursal Disease in an Integrated Broiler Production Operation

Abstract

Abstract. A field study was designed to determine the prevalence of subclinical infectious bursal disease (IBD) in broiler chickens from a commercial poultry company. Bursae of Fabricius (BF) from two vaccinated and three nonvaccinated broiler flocks were evaluated histologically, and antibody profiles of these broiler and matched parent breeder flocks were established. Lesions of IBD, including lymphoid necrosis, stromal edema, and infiltrates of heterophils and macrophages, were first detected in BF at 24 days of age in both vaccinated and nonvaccinated chickens. At 41 days, all BF had lesions characteristic of IBD, including severe lymphoid depletion, proliferation of epithelial cells, and mild fibroplasia. Although mean maternal antibody levels (measured by enzyme-linked immunosorbent assay) in broilers were apparently protective through day 12, IBD antibodies decreased to nonprotective levels (below 1,000) by day 16 or 20. Titers began to increase by day 28 or 32 because of field exposure. Sentinel birds, placed with broiler flocks, also developed IBD antibody titers. Broiler breeders had low and nonuniform antibody titers. Prevalence of field IBD exposure was high, and existing vaccination programs were not effective.Infectious bursal disease (IBD) is a highly contagious may develop a yellow gelatinous transudate by day 2 viral infection (birnavirus) of immature chickens, or 3 postinfection, followed by progressive atrophy and characterized by necrosis and depletion of lymphoid reduction in size beginning at day 5.12 Degeneration tissues, particularly the bursa of Fabricius (BF).12,14 The and necrosis of follicular lymphocytes can be detected disease is a major problem in concentrated broiler pro-microscopically at day 1 postinfection, soon followed ducing areas of the United States.16,l7 Chickens infected by follicular and interfollicular infiltrates of heterowith IBD at < 3 weeks of age have subclinical infections phils, accumulation of cellular debris, proliferation of characterized by bursal atrophy, resulting in severe im-follicular stromal cells, and interfollicular edema. 4,7 These birds exhibit increased in-There is progressive phagocytosis of necrotic lymphocidence of other infections such as colibacillosis, sal-cytes. Lymphoid depletion and atrophy are predomimonellosis, and coccidiosis, resulting in higher growout nant at day 5, after which there is proliferation and mortality and increased condemnations at processing. metaplasia of corticomedullary epithelium with forChickens with clinical IBD (usually infected at 3-6 mation of glandular structures and interfollicular fiweeks of age) present with diarrhea, vent picking, trem-broplasia. Virus can be isolated from the BF or deors, transient immunosuppression, and higher mor-tected by immunofluorescence, agar-gel precipitin tality at the time of infection. The IBD virus is ex-(AGP) assay, electron microscopy, or dot blot hybridtremely stable and resistant to disinfectants and normal ization.6 Serologic testing using enzyme-linked imsanitation proc...

Effects of different broiler production systems on health care costs in the Netherlands

“…In case of no vaccination, morbidity in the flock is 90% (Cook et al, 1999;Cavanagh, 2003). 2 Although Homer et al (1992) found a prevalence rate of 13.3%, the present study assumed that birds have been vaccinated against infectious bursal disease (IBD), indicating that IBD does not occur on the farm. Cavanagh (2003) suggested that vaccination against IBD provides 100% protection.…”

Parasite‐induced maternal response in a natural bird population

“…1994). Maternal antibodies protected chicken against clinical haemorrhagic enteritis (Fadly & Nazerian 1989), against avian leukosis virus (Fadly & Smith 1991) and against infectious bursal disease (Komine 1989;Homer et al . 1992).…”

Epidemiology of infectious bursal disease in broiler birds of three districts in Bangladesh

“…Infectious bursal disease (IBD) is an acute, highly contagious, immunosuppressive and economically important poultry disease caused by Birnaviridae RNA virus (Cosgrove, 1962;Lukert and Saif, 2003;Islam, 2005;Okwor et al, 2011). The disease damage the humoral immunity producing lymphoid organ Bursa of Fabricius and result in immuno-suppression and increase susceptibility of poultry to opportunistic secondary infection such as Marek's disease and Newcastle disease (Faragher et al, 1974;Homer et al, 1992;Khan et al, 2011;Mahgoub, 2012). Broiler bird aged between 21-30 days are most susceptible to IBD infection (Mor et al, 2010).…”