Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Laboratory of Anatomy of Domestic Animals, College of Animal Medicine, China Agricultural University, Beijing 100193, China.
Vet Microbiol. 2018 Dec;227:20-28. doi: 10.1016/j.vetmic.2018.10.019. Epub 2018 Oct 24.
TW-like IBV isolates have appeared frequently in recent years in mainland China. In this study, we compared the TW-like IBV GD strain and the predominant QX-like SD strain in terms of serology and pathogenicity to 3-week-old specific-pathogen-free chickens. Both strains could cause severe respiratory distress and renal lesions, with a mortality rate were approximately 20%. Virus were continuously shed via the respiratory tract and cloaca. However, the infection pattern of the two isolates were different. The GD strain persisted for a longer duration and caused extensive damages to the tracheas and lungs. Moreover, chickens infected with the GD strain showed inefficient recovery of damaged cilia after infection. Our findings suggested that the newly emerged TW-like IBV GD strain showed obvious differences in pathogenicity, tissue tropism and replication efficiency compared with the QX-like IBV SD strain, with the TW-like GD strain showing stronger tropism to the respiratory tract and a longer duration of clinical signs.
近年来，TW 样 IBV 分离株在中国大陆频繁出现。在这项研究中，我们比较了 TW 样 IBV GD 株和主要的 QX 样 SD 株在血清学和对 3 周龄 SPF 鸡的致病性方面的差异。两种毒株均可引起严重的呼吸窘迫和肾脏病变，死亡率约为 20%。病毒通过呼吸道和泄殖腔持续排出。然而，两种分离株的感染模式不同。GD 株持续时间更长，对气管和肺部造成广泛损伤。此外，感染 GD 株的鸡在感染后受损纤毛的恢复效率较低。我们的研究结果表明，新出现的 TW 样 IBV GD 株与 QX 样 IBV SD 株相比，在致病性、组织嗜性和复制效率方面表现出明显差异，TW 样 GD 株对呼吸道的嗜性更强，临床症状持续时间更长。
