Sporadic Outbreaks of Avian Infectious Bronchitis Viruses Highly Similar to the S95 Live Attenuated Vaccine Strain in Japan: A Comparative Study of Ten Field Isolates and S95.

ABSTRACT:

Background

As infectious bronchitis virus (IBV) strains similar to the IBV S95 live attenuated vaccine strain have been occasionally detected in poultry farms in Japan, we investigated the suspicion that outbreaks of the disease were related to the S95 vaccine.

Methods

We isolated ten S95 vaccine-like strains, classified in the JP-I genotype of S1, the VIb (Y-4) genogroup of S2, and the GI-18 lineage, from IBV-affected chickens in Japan between 2020 and 2024. The whole-genome sequence and adaptation to embryonated chicken eggs were investigated. We developed a method for distinguishing the S95 vaccine strain from S95-like wild-type strains using specific primer sets having either the S95 vaccine or S95 parent-specific nucleotide at the 3' termini of primers on the ORF2

SUBMITTER: Nukui R 

PROVIDER: S-EPMC12656252 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature