Repeated avian infectious bronchitis virus infections within a single chicken farm

Abstract

Genotyping of avian infectious bronchitis virus (IBV) was performed on trachea and kidney samples of six chickens obtained from a single farm in Japan. Using two primer sets targeting the spike (S) protein gene, the S1 and S2 regions of DNA fragments were amplified. Sequences of amplified S1 fragments extracted from both organs were identical among the six chickens, showing a JP-I genotype. Sequences of amplified S2 fragments differed between trachea and kidney samples. The kidney profile showed a group IV genotype, whereas the trachea profile showed an unclassified group. This result showed that two different IBVs infected the six chickens. The first IBV infection induced poor protective immunity in this farm, permitting a second IBV infection to occur.

Bacterial artificial chromosome-based reverse genetics system for cloning and manipulation of the full-length genome of infectious bronchitis virus

“…To eliminate contamination of the BAC-cloned IBV cDNA used for transfection, RNA prepared from the transfected 293T cells was treated with RQ1 RNase-free DNase (Promega, Madison, WA) and then RNAs were concentrated by isopropanol precipitation. RNA samples were reverse transcribed by SuperScript II Reverse Transcriptase (Thermo Fisher Scientific), and a 400 bp fragment from the IBV S2 subunit was amplified using PrimeSTAR Max Polymerase (Takara Bio Inc.) as previously reported ( Kato et al., 2019 ; Lin et al., 1991 ).…”

Molecular survey of infectious bronchitis virus on poultry farms in Gifu Prefecture, Japan from 2021 to 2022 by RT-PCR with an enhanced level of detection sensitivity for the S1 gene

“…established RT-PCR for genotyping Japanese IBV strains based on S1 gene analysis, which enabled identification of seven genotypes (JP-I, JP-II, JP-III, JP-IV, Mass, Gray, and 4/91) [ 15 , 17 , 18 ]. The method developed by Mase et al has been used for molecular surveys of IBV in Japan by several groups [ 7 , 9 , 10 ], and the utility of the method for selection of appropriate vaccines against IB in Japan has been demonstrated. Kaneda et al .…”

Genotyping of infectious bronchitis viruses isolated in Japan during 2008−2019

“…Therefore, analysis of the S2 gene is important for understanding the antigenicity and cellular tropism of the isolates. Most importantly, the antigenic diversity in IBV may arise from a recombination between strains classified into different genetic groups [ 9 , 12 ].…”

“…The effect of recombination on the antigenicity, virulence, replication, shedding, and tissue tropism of the virus warrants further study. Two field IBVs used to successively infect chickens in a short-period on a farm were suggested to generate recombinant strains in infected poultry [ 12 ]. Therefore, clarifying the mechanism of emergence of recombinant viruses due to infection with multiple IBV strains is important.…”