Seroepidemiology of Infectious Bursal Disease in Poultry Reared Under Backyard Production System in Wolaita Zone, Southern Ethiopia

Background: Infectious bursal disease (IBD) has been known to cause high morbidity and mortality in chickens resulting in considerable financial losses to poultry producers. This study was performed with the objectives of estimating the seroprevalence and associated risk Methods: A total of 482 serum samples were collected from chickens reared under backyard systems using a multi-stage cross-sectional study design. The serum samples were tested for the presence of anti-IBDV antibodies using an indirect enzyme-linked immunosorbent assay (ELISA). A questionnaire survey was also performed to identify risk factors affecting chicken production in the study area. Results: From the total of 482 serum samples tested, 236 (48.96%; 95% CI: 44.32-53.42) were positive for anti-IBDV antibodies. Higher seroprevalence was recorded in Humbo district (55.75%; 95% CI: 46.11-65.09) followed by Sodo Zuria (51.54%; 95% CI: 42.62- 60.39), Damotgale (46.22%; 95% CI: 36.49-56.18), and Kindokoysha district (42.86%; 95% CI: 34.32-51.72) although the difference was not statistically significant. Significantly lower prevalence was recorded in indigenous chickens (43.36%; 95% CI: 37.53-49.32) compared to exotic chickens (57.14%; 95% CI: 49.89-64.17). The odds of occurrence of IBD in the local chicken breed was 0.67 times lower than that of the exotic chicken breed. The odds of occurrence of IBD in chickens from flock size >= 5 chickens was 4.33 times higher than chickens from flock size <5 chickens. A statistically significant association (P < 0.05) was observed between treatment history and isolation of sick chickens with mortality in the flock. Conclusion: This study revealed that IBD is one of the major infectious diseases that affect the traditionally managed chickens in the study area with the flock size and breed of chickens are identified as important risk factors for IBD occurrence. Besides, chicken producers did not have enough knowledge about the nature and epidemiology of IBD. Thus, proper management practices together with appropriate vaccination programs are necessary to reduce IBD incidence in the study areas.