Sequencing and phylogenetic analysis of infectious bronchitis virus variant strain from an outbreak in egg-layer flocks in Baghdad, Iraq

Background and Aim: Infectious bronchitis (IB) has an influential economic impact on the poultry industry, causing huge losses each year due to the condemnation of infected chickens. Despite the use of many kinds of vaccines in Iraq, it is common to find IB problems in vaccinated chickens. Information about the strains that affect Iraqi chickens is very limited. Therefore, we aimed to detect the currently circulating strains of IB virus that cause frequent outbreaks in egg layers despite the use of vaccination against the virus. Materials and Methods: Isolate detection, sequencing, and phylogenetic analysis were performed using a rapid IB virus antigen kit (32 tracheal swabs), flinders technology associates (FTA) card (32 tracheal swabs), and partial gene sequencing (16 positive FTA samples). Results: The isolated strain was different from other strains, especially the strain isolated in the North of Iraq (Sulemania Strain) and shares 98% homology with an Israeli strain (Israel variant 2, IS 1494). Conclusion: Although more studies are needed to detect IB virus strains circulating in Iraq, this work lays the foundation for making a good strategy to control the disease and selecting vaccines that should be used in farms.