Abstract

Infectious Bronchitis is one of the major viral diseases affecting poultry causing severe economic losses. The prevalence of Infectious Bronchitis viruses was studied in commercial chicken farms in Egypt between 2014 and 2016. A total of 1722 organ samples (trachea, kidney, caecal tonsils and lungs) were collected from 246 problematic flocks, showing respiratory signs and considerable mortalities, from 13 governorates throughout the examination period and were then subjected to molecular analysis using real-time reverse transcription-polymerase chain reaction. Data from this study have shown a high prevalence (75.6%) of Infectious Bronchitis virus in Egyptian farms. Infections mixed with other respiratory viruses were frequently observed, including very virulent Newcastle disease, Low pathogenic avian influenza, H9N2 and High pathogenic avian influenza H5N1 with 27.9%, 25.7% and 17.1%, respectively with higher detection percentages observed in the winter season. Phylogenetic analysis of 19 selected positive Infectious Bronchitis virus has revealed Infectious Bronchitis virus genotypes closely related to variant II strains Eg/12120S/2012, IS/885, IS/1494, with 4 isolates was clustered in a new group. In conclusion, the present study provides further updates on the circulation and co-circulation of Infectious Bronchitis virus in commercial Egyptian flocks. The continuous existence of field variant Infectious Bronchitis virus in commercial chicken's farms in Egypt emphasizes the need for regular monitoring of Infectious Bronchitis with updating the control and vaccination strategies.