Phylogenetic analysis of infectious bursal disease virus strains delivered from natural infection in last decade during 2013-2022, Egypt

Abstract

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive disease of chickens resulting in global economic losses to the poultry industry despite extensive vaccination. The emergence of very virulent IBDVs in global epizootics, including those from Egypt, demonstrates how occasionally occurring genetic changes lead to simultaneous evolution of distinct IBDV strains across the world. Upon phylogenetic analysis of Egyptian IBDVs, virus strains from chickens and turkey (n= 146) were clustered within genogroup 3, whereas, twenty nine isolates were closely related to vaccinal strains in genogroup 1. Regarding to sequences from wild birds (cattle egret and green winged teal) were clustered within G1a (n=2) and G3a (n=1) subgen groups. The highest IBDV percentages during 2013-2022 was in 2020 (n=71; 20%) and in Behera Province (n= 54; 15.3%) followed by Sharkia Province (n= 51; 14.4%). The data revealed the characteristic molecular traits of IBDVs circulating in Egypt between 2013 and 2022, which will help in development of effective vaccines subsequently disease prevention. In addition to, it offers helpful insights for carrying out further surveys that are required to increase the understanding of IBDV prevalence in wild migratory and free-living birds.