Seroprevalence and Coinfection of Infectious Bursal Disease in Chickens Raised under Backyard Production Systems in Wag-Lasta, Amhara, Ethiopia

Abstract Infectious bursal disease (IBD) is a highly contagious and immunosuppressive disease that primarily affects young chickens. This disease can lead to severe economic losses in the poultry industry due to high mortality rates and decreased productivity. In Ethiopia, IBD is believed to have been introduced in the early 21st century through the importation of exotic breeds. The disease exhibits a high prevalence, being reported in more than 95% of WOAH member countries, showcasing diverse strains. Therefore, this study aimed to investigate the seroprevalence of IBD in the Wag-Lasta area of the Amhara region, assess coinfection, and identify risk factors associated with disease occurrence. A total of 329 blood samples were collected from chickens in three agroclimatic zones of the Amhara region. Serological testing revealed that 53.8% of the samples were positive for infectious bursal disease. Compared with lowland areas, highland regions presented a greater prevalence (48.09%) of IBD (40.40%), whereas the prevalence was highest in midland areas (74.74%). The study revealed a strong association between the occurrence of IBD and the agroecological zones where the chickens were raised. Compared with local chickens, exotic chicken breeds presented greater odds of disease (OR = 34.57: 95% CI 16.44–72.72; P = 0.000), and highland areas (OR = 4.87; 95% CI 2.18–10.91; P = 0.000) presented greater odds of testing positive than lowlands did. IBD can cooccur with other diseases, notably salmonellosis and Newcastle disease. The high prevalence of IBD highlighted in the present study can lead to increased susceptibility to other infections, emphasizing the significant economic impact of the disease in the region. Understanding the epidemiology and risk factors associated with IBD is crucial for developing effective control strategies to reduce the burden of this economically significant poultry disease in the region.