ABSTRACT
We report the complete genome sequences of strains JP/Yamanashi/93 and JP/Shimane/98, which are classified in JP-II (GI-7) and JP-III (GI-19), respectively, the major genotypes of infectious bronchitis virus (IBV) in Japan. This information will be useful for the in-depth understanding of the evolution of IBV in Japan.
ABSTRACT
We report the complete genome sequences of two strains of JP-1 genotype (GI-18) infectious bronchitis virus (IBV) isolated from the kidneys of dead chickens in Japan in 2000 and 2017. This information will help researchers better understand the evolution and epidemiology of IBV in Japan.
ABSTRACT
The complete nucleotide sequence of the S1 glycoprotein gene of the Japanese infectious bronchitis virus (IBV) strains was determined and genetically analyzed. A total of 61 Japanese IBV strains were classified into seven genotypes, namely GI-1, 3, 7, 13, 18, 19, and GVI-1 using the classification scheme that was proposed by Valastro et al, with three exceptions. These genotypes practically corresponded to those defined in Japan, namely Mass, Gray, JP-II, 4/91, JP-I, JP-III, and JP-IV, which have been identified through their partial nucleotide sequences containing hypervariable regions 1 and 2. In addition, three exceptive strains were considered to be derived from recombination within the S1 gene of IBV strains G1-13 and GI-19. By analyzing the amino acid polymorphism of the S1 glycoprotein among Japanese genotypes, a diversity was observed based on the genotype-specific amino acid residue, the proteolytic cleavage motif at the S1/S2 cleavage site, and the position of the potential N-glycosylation sites.
Subject(s)
Coronavirus Infections , Infectious bronchitis virus , Poultry Diseases , Amino Acids/genetics , Animals , Chickens , Coronavirus Infections/veterinary , Glycoproteins/genetics , Infectious bronchitis virus/genetics , Japan , PhylogenyABSTRACT
Infectious bronchitis virus (IBV) causes respiratory diseases in chickens and poses an economic threat to the poultry industry worldwide. Despite vaccine use, there have been field outbreaks of IBV in Taiwan. This study aimed to characterize the emerging IBV variants circulating in Taiwan. The analysis of the structural protein genes showed that these variants emerged through frequent recombination events among Taiwan strains, China strains, Japan strains and vaccine strains. Cross-neutralization tests revealed that two of the variants exhibited novel serotypes. Clinicopathological assessment showed that two of the variants caused high fatality rates of 67% and 20% in one-day-old SPF chicks, and all the variants possessed multiorgan tropisms, including trachea, proventriculus and urogenital tissues. Furthermore, the commercial live-attenuated Mass-type vaccine conferred poor protection against these variants. This study identified novel genotypes, serotypes and pathotypes of emerging IBV variants circulating in Taiwan. There is an urgent need for effective countermeasures against these variant strains.