Nan Jiang , Yulong Wang , Wenying Zhang , Xinxin Niu, Yulong Gao , Li Gao, Kai Li, Hongyu Cui , Aijing Liu , Qing Pan, Changjun Liu, Yanping Zhang , Xiaomei Wang , Xiaole Qi 

Virus Res.2021 Jul 2;302:198498.doi: 10.1016/j.virusres.2021.198498. Online ahead of print.

Abstract

Infectious bursal disease virus (IBDV), the causative agent of infectious bursal disease (IBD), mainly damages the bursa of Fabricius, which is a central immune organ of birds. As an RNA virus, IBDV is prone to mutation owing to a combination of factors including natural selection pressure. In this study, a naturally occurring mutated IBDV associated with bursa damage was identified, IBDV-HeN20-7103 strain, in an infected chicken flock in central China. Its full-length genome was cloned, and sequence analysis showed that the IBDV-HeN20-7103 strain was located along with the attenuated IBDV, which corresponds to genotype A8B1 of the recently proposed classification scheme, on the branch of the phylogenetic tree. The amino acid sequence comparisons further highlighted the specific characteristics of IBDV-HeN20-7103 with mutation H253Q compared to the attenuated strain. Animal experiments showed that IBDV-HeN20-7103 could induce serious bursal lesions without mortality, which revealed a unique cause of disease in this flock. The identification of such a strain reaffirms the complexity of IBDV evolution and prevalence.

Keywords: A8B1; Genome; Infectious bursal disease virus; Mutant; Pathogenicity.

Copyright © 2021. Published by Elsevier B.V.