Department of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
Division of Viral Disease and Epidemiology, National Institute of Animal Health, National Agriculture and Food Research Organization, Ibaraki, Japan.
Transbound Emerg Dis. 2020 Mar;67(2):884-893. doi: 10.1111/tbed.13412. Epub 2019 Nov 20.
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.
传染性支气管炎病毒(IBV)可引起鸡的呼吸道疾病,对全球家禽业造成经济威胁。尽管使用了疫苗,但台湾仍有 IBV 的田间暴发。本研究旨在描述台湾流行的 IBV 变异株。结构蛋白基因分析表明,这些变异株通过台湾株、中国株、日本株和疫苗株之间的频繁重组事件而出现。交叉中和试验表明,两种变异株具有新型血清型。临床病理评估显示,两种变异株可导致 1 日龄 SPF 雏鸡的高死亡率,分别为 67%和 20%,所有变异株均具有多器官嗜性,包括气管、前胃和泌尿生殖道组织。此外,商业减毒 Mass 型疫苗对这些变异株的保护效果不佳。本研究鉴定了台湾流行的新型 IBV 变异株的基因型、血清型和病理型。迫切需要针对这些变异株采取有效的对策。