Abstract

Infectious Bronchitis (IB) is a viral respiratory disease of chickens that is associated with huge economic losses. This study was designed to investigate its seroprevalence in unvaccinated exotic and indigenous chickens in some States of South-western Nigeria. Sera samples (n=750) were obtained from unvaccinated, intensively reared, exotic chickens (n=450) and unvaccinated extensively reared indigenous chickens (n=300) from Lagos, Ogun, and Oyo States. The antibodies to the IB virus were detected in serum utilizing enzyme-linked immunosorbent assay. Descriptive statistics, ANOVA, and an independent t-test were used to analyze the data. On average, 81.1% were seropositive to IB virus, distributed as 78.0%, 86.8%, and 78.4% in Lagos, Ogun, and Oyo States, respectively. Seroprevalence was high in both exotic (82.4%) and indigenous (79.0%) chickens, while mean antibody titres were significantly higher in exotic (49.74 ± 2.50 and 43.25 ± 4.64) than in indigenous chickens (24.71 ± 2.02 and 31.85 ± 2.24) in Lagos and Oyo states, respectively. Indigenous chickens raised in south-western Nigeria are likely exposed to infectious bronchitis virus in the environment and the presence of the antibodies in these chickens is an indicator of the endemicity of the virus. This also identifies a possible role for indigenous chickens in the dissemination of the virus. There is a need for continuous surveillance, improved vaccination, and stricter biosecurity measures in poultry production for optimal control of infectious bronchitis in Nigeria.

Key words: Chicken, Infectious Bronchitis, Poultry infection, Seroprevalence, Respiratory disease