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

Abstract

A B S T R A C TTwo viruses were isolated in 2017 from commercial pheasants with severe clinical signs and mortality in Shandong and Anhui provinces, China, respectively. We examined the pathogenic effects of the viruses in chicken embryos and the size and morphology of the virus particles, performed phylogenetic analysis based on the S1 gene and complete genomic sequences, and examined the antibody responses against infectious bronchitis virus (IBV). The results suggested that the viruses I0623/17 and I0710/17 were avian coronaviruses and were identified as pheasant coronaviruses (PhCoV), with greatest similarity to IBV. Further investigations of the antigenicity, complete genome organization, substitutions in multiple genes, and viral pathogenicity, replication, and shedding in chickens and pheasants showed obvious differences between PhCoV and IBV in terms of antigenicity, and viral pathogenicity, replication, and shedding in chickens and pheasants. The close genetic relationship, but obvious differences between PhCoVs and IBVs suggested the IBVs could be the ancestors of PhCoVs, and that PhCoVs isolated from different outbreaks may have evolved independently from IBVs circulating in the specific region by adaption in pheasants. This hypothesis was supported by analysis of the S1 gene fragments of the two PhCoVs isolated in the current study, as well as PhCoVs isolated in the UK and selected IBV strains. Such analyses indicated different evolution patterns and different tissue tropisms between PhCoVs isolated in different outbreaks. Further studies are needed to confirm this hypothesis by studying the complete genomic sequences of PhCoVs from different outbreaks and the pathogenicity of IBVs in pheasants to compare and clarify the relationships between PhCoVs and IBVs.

Genome composition and genetic characterization of SARS-CoV-2

“…Once the binding occurs, conformational changes in the S protein, like pH reducing and/or S protein proteolysis, promote splitting of S1 from S2. Consequently, membrane fusion is placed by the S2 region ( Han et al, 2020 ). S2 subunit has two heptad repeat (HR) domains, (HR1) and (HR2), that interact together to form a six-helix bundle (6-HB) fusion core to approximate the viral and cellular interaction ( Xia et al, 2020 ).…”

Pathology of Coronavirus Infections: A Review of Lesions in Animals in the One-Health Perspective

“…PhCoVs belong to the genus Gammacoronavirus and subgenus Igacovirus [ 233 , 235 ] and have a high degree of genetic similarity with chicken and turkey CoVs [ 258 , 259 , 260 , 261 ]. Han and collaborators reported different evolution patterns and tissue tropisms between different PhCoVs [ 262 ]. Cavanagh and collaborators confirmed that CoVs that naturally infect pheasants are genetically similar to IBV, but they do not cause disease when inoculated experimentally in chickens, even if antibodies are produced [ 243 , 258 , 260 ].…”

“…Cavanagh and collaborators confirmed that CoVs that naturally infect pheasants are genetically similar to IBV, but they do not cause disease when inoculated experimentally in chickens, even if antibodies are produced [ 243 , 258 , 260 ]. Additional studies of the complete genomic sequence are necessary to better understand the relation between the pathogenicity of IBVs in pheasants and clarify the link between PhCoVs and IBVs [ 262 ]. Outbreaks associated with CoVs infection in pheasants were reported for the first time in the 1980s.…”

“…Outbreaks associated with CoVs infection in pheasants were reported for the first time in the 1980s. PhCoV was isolated in the UK [ 260 , 261 , 263 ] and in China [ 262 ]. Grossly, the celomic cavity usually shows visceral gout, swollen and pale kidneys, with distended ureters with urates and urolithiasis [ 260 , 263 ].…”

Design and Characterization of a DNA Vaccine Based on Spike with Consensus Nucleotide Sequence against Infectious Bronchitis Virus

“…IBV is associated with a high frequency of point mutations, insertions, deletions, and recombination [ 1 , 6 ]. Currently, IBV is comprised of seven genotypes that together include 36 distinct viral lineages and several unique variants [ 7 , 8 , 9 ]. Among these genotypes, GI-19 (also called QX-like) has expanded globally in recent years [ 2 , 6 ].…”