Sero-prevalence and serotypes of infectious bronchitis virus in free-range chicken in Plateau state, Nigeria

Globally, infectious bronchitis (IB) is an important respiratory viral disease responsible for enormous economic losses to poultry farmers.  In Nigeria, limited reports on the prevalence and serotypes of the IB virus are available. Here, we investigated the prevalence and serotypes of infectious bronchitis virus (IBV) in chicken in Plateau State. A descriptive cross-sectional study was carried out involving 440 apparently healthy free-range local chickens sampled from eleven villages in four Local Government Areas (LGA) of Plateau State. Sera collected from the birds were screened for the presence of four IBV serotypes namely; Massachusetts (Mass), Arkansas (Ark), Connecticut (Con) and Delaware (De-072) using haemagglutinationinhibition (HI) test. In all, a prevalence of 82.95% (n = 365) was recorded. At LGAlevel, prevalence of 79.50%, 47.37%, 95.45% and 100% were recorded in Kanam, Mangu, Qua’an pan and Bassa LGAs, respectively. Based on serotype prevalence, Mass had 89.30% (n = 326); Ark 79.70% (n = 291); Con 88.20% (n = 322) while De-072 was 42.70% (n = 156). There were statistically significant associations between dominant serotype and the LGAs (p≤0.001). This study shows high prevalence of IBwith at least four strains of IBV present in free-range chicken flocks in Plateau State requiring attention for control measures. Keywords: Free-range chicken; Infectious bronchitis virus; Plateau state, Serosurvey, Serotype