Genomic sequence analysis of a new reassortant infectious bursal disease virus from commercial broiler flocks in central China

Abstract

We report the complete nucleotide sequence of a reassortant infectious bursal disease (IBD) virus (IBDV) HN isolate from commercial broiler flocks in central China. The genome consisted of 3,232 and 2,652 nucleotides in the coding regions of segments A and B, respectively. Alignment of both nucleotide and deduced amino acid sequences and phylogenetic analysis revealed that the genome segments A and B of HN were derived from the attenuated strain B87 and the VV strain OKYM. This is a new reassortant IBDV strain that has emerged in nature, involving segment A of a cell-culture-adapted attenuated vaccine strain B87.

Identification of a European interserotypic reassortant strain of infectious bursal disease virus

“…The resulting viruses may contribute to pathology in the field, as they induce clinical disease (this study and Jackwood et al, 2011) and probably result in immunosuppression in infected birds. Nonetheless, interserotypic reassortments may represent relatively rare events, with only two documented occurrences, when compared with intraserotypic reassortments that have been repeatedly described during the last 10 years (Le Nouen et al, 2006;Wei et al, 2006Wei et al, , 2008Gao et al, 2007;Cui et al, 2013;Kasanga et al, 2013;Li et al, 2015). Such events should not be neglected as they can result in the emergence of viruses with increased virulence (Li et al, 2015), which is consistent with the idea that both segments contribute to IBDV pathogenicity (Escaffre et al, 2013).…”

“…The segmented nature of IBDV genome raises the possibility of reassortment when cells are co-infected by two distinct IBDV strains. Reassortment between serotype 1 strains (producing intraserotypic reassortants) has already been described (Le Nouen et al, 2005;Wei et al, 2006Wei et al, , 2008Gao et al, 2007;Cui et al, 2013;Kasanga et al, 2013;Li et al, 2015). Reassortant viruses often have a decreased pathogenicity compared with their most pathogenic parental strains (Le Nouen et al, 2006;Wei et al, 2006Wei et al, , 2008.…”

Differential gene expression in chicken primary B cells infected ex vivo with attenuated and very virulent strains of infectious bursal disease virus (IBDV)

“…Vaccines fail to induce sterilizing immunity, and vaccinated birds may continue to shed wildtype strains and reassortant viruses that contain genome segments from both vaccine and field strains [27,28]. Moreover, antigenically variant viruses have emerged on several occasions, necessitating the development of novel vaccines [7,8], and a pathotypic variant, the very virulent strain, emerged in the late 1980s (apparently by reassortment) to spread across the globe, often necessitating the use of less attenuated vaccines [6,9,10].…”

Differential gene expression in chicken primary B cells infectedex vivowith attenuated and very virulent strains of infectious bursal disease virus (IBDV)

“…Despite decades of vaccination, IBDV continues to be endemic world-wide and frequently ranks in the top 5 diseases of poultry (3). Vaccines fail to induce sterilising immunity, and vaccinated birds may continue to shed wild-type strains and reassortant viruses that contain genome segments from vaccine and field strains (27, 28). Moreover, antigenically variant viruses have emerged on several occasions, necessitating the development of novel vaccines (7, 8) and a pathotypic variant, the very virulent strain, emerged in the late 1980s (apparently by reassortment) to spread across the globe, often necessitating the use of less attenuated vaccines (6, 9, 10).…”