Genome characterization, antigenicity and pathogenicity of a novel infectious bronchitis virus type isolated from south China

Abstract

In 2014, three infectious bronchitis virus (IBV) strains, designated as γCoV/ck/China/I0111/14, γCoV/ck/China/I0114/14 and γCoV/ck/China/I0118/14, were isolated and identified from chickens suspected to be infected with IBV in Guangxi province, China. Based upon data arising from S1 sequence and phylogenetic analyses, the three IBV isolates were genetically different from other known IBV types, which represented a novel genotype (GI-29). Virus cross-neutralization tests, using γCoV/ck/China/I0111/14 as a representative, showed that genotype GI-29 was antigenically different from all other known IBV types, thus representing a novel serotype. Complete genomic analysis showed that GI-29 type viruses were closely related to and might originate from a GX-YL5-like virus by accumulation of substitutions in multiple genes. These GI-29 viral genomes are still evolving and diverging, particularly in the 3' region, although we cannot rule out the possibility of recombination events occurring. For isolate γCoV/ck/China/I0114/14, we found that recombination events had occurred between nsps 2 and 3 in gene 1 which led to the introduction of a 4/91 gene fragment into the γCoV/ck/China/I0114/14 viral genome. In addition, we found that the GI-29 type γCoV/ck/China/I0111/14 isolate was a nephropathogenic strain and high pathogenic to 1-day-old specific pathogen-free (SPF) chickens although cystic oviducts were not observed in the surviving layer chickens challenged with γCoV/ck/China/I0111/14 isolate.

A novel low virulent respiratory infectious bronchitis virus originating from the recombination of QX, TW and 4/91 genotype strains in China

“…Therefore, it is necessary to analyze the complete genome of some isolated strains to monitor the recombination event. Genome-wide sequences of recombinant IBV strains obtained by Sanger sequencing were reported in previous studies Jiang et al, 2017;Wu et al, 2016). In this study, we isolated JX17 strain from yellow feather broilers vaccinated with H120 and 4/91 vaccines and got monocle IBV virus by limiting dilution passages.…”

Novel genotype of infectious bronchitis virus isolated in China

“…The full S1 gene sequence generated in this study was subjected to BLAST searches using the National Center for Biotechnology Information database, and then analyzed phylogenetically using a dataset consisting of 73 sequences ( Supplemental Table 1), including representative sequences for each genotype and lineage, as recently recommended (Valastro et al, 2016;Chen et al, 2017;Jiang et al, 2017), and the GX-NN130021 strain, which was closely related to I0636/16 by BLAST analysis. The S1 gene sequences of the IBV strain I0636/16 and the selected viruses were aligned using ClustalW, and phylogenetic analysis was carried out using Mega version 6.0 software (http://www.…”

“…Antisera against the viruses H120, 4/91, LDL/091022, LDL/97I, LSC/99I, LGX/111119, and I0111/14 Chen et al, 2017;Jiang et al, 2017) were used in this study. Antisera against strains I0725/17 and I0636/16 were produced in this study following a standard protocol .…”

“…In addition, IBV variants of indigenous lineages were also found to be circulating in chicken flocks in China. New lineages, GI-7 , GI-28, and GI-29 (Chen et al, 2017;Jiang et al, 2017), were recently found in chickens suffering from respiratory and urinary health problems. These results indicated that novel IBV lineages have been emerging continuously in China in recent years.…”

Genetic, antigenic and pathogenic characterization of avian coronaviruses isolated from pheasants (Phasianus colchicus) in China

“…This is expressed as an accelerated rate at which viable point mutations, nucleotide insertions, or deletions accumulate in the genome, especially in the S1 gene, associated with a lack of proofreading viral polymerase in IBVs (Cavanagh, 2007), as well as the high rate of virus replication. In addition, evidence suggests that some IBV strains may have arisen by genetic recombination (Cavanagh et al, 1992;Kusters et al, 1989Kusters et al, , 1990, or by a combination of mutation and recombination (Jia et al, 1995;Chen et al, 2017;Jiang et al, 2017). TCoV, initially found in the 1970s, is associated with the enteric disease known as transmissible enteritis, coronaviral enteritis of turkeys, or bluecomb (Guy, 2008).…”