Alsultan Musaed Abdulaziz, Alhammadi Mohamed Ali, Hemida Maged Gomaa
Training Veterinary Center, Ministry of Environment, Water and Agriculture, Saudi Arabia.
Department of Microbiology and Parasitology, College of Veterinary Medicine, King Faisal University, Saudi Arabia.
Vet World. 2019;12(3):424-433. doi: 10.14202/vetworld.2019.424-433. Epub 2019 Mar 19.
This study aimed to isolate some of the currently circulating infectious bronchitis virus (IBV) strains from some broiler chicken farms in Al-Hasa and to do some molecular characteristics of these strains.
We collected 300 tissue specimens, including the trachea, bronchi, lungs, and kidneys from some four commercial chicken farms showing respiratory manifestations. We tested these tissue specimens by the real-time polymerase chain reaction (RT-PCR) and gel-based PCR. We selected some PCR positive samples for isolation in the embryonated chicken eggs (ECE). We sequenced some PCR-positive samples and conducted phylogenetic analysis based on the obtained sequences.
Our molecular surveillance revealed that 31.6% of the tested specimens were IBV positive by PCR. We selected some positive specimens showing low Ct values by the qRT-PCR for virus isolation by the ECE. The infected eggs showed hemorrhage, dwarfing, and death in some cases after three passages in the ECE. We sequenced some of the positive PCR specimens and used the obtained sequences to draw the phylogenetic tree based on the partial IBV-ORF-1a, N, and S1 gene sequences. The phylogenetic trees based on the IBV-N and S1 gene sequences showed that the circulating IBV strains in Al-Hasa during 2016 was showing a high degree of identity to some strains from Taiwan and Italy. Meanwhile, the grouping of these strains based on the IBV-S1 sequences revealed that the currently circulating IBV strains in Al-Hasa belonged to Gr.I.7 along with strains from Taiwan.
Our results confirmed the continuous circulation of the IBV among the chicken population in Al-Hasa despite the intensive application of vaccines against this virus.
本研究旨在从哈萨的一些肉鸡养殖场分离出一些当前流行的传染性支气管炎病毒（IBV）毒株，并对这些毒株进行一些分子特征分析。
我们从四个出现呼吸道症状的商业养鸡场收集了300份组织标本，包括气管、支气管、肺和肾脏。我们通过实时聚合酶链反应（RT-PCR）和基于凝胶的PCR对这些组织标本进行检测。我们选择了一些PCR阳性样本在鸡胚（ECE）中进行分离。我们对一些PCR阳性样本进行测序，并根据获得的序列进行系统发育分析。
我们的分子监测显示，31.6%的检测标本通过PCR呈IBV阳性。我们选择了一些通过qRT-PCR显示低Ct值的阳性标本，通过ECE进行病毒分离。在ECE中传代三次后，一些感染的鸡胚出现出血、发育不良和死亡。我们对一些PCR阳性标本进行测序，并根据获得的序列，基于部分IBV-ORF-1a、N和S1基因序列绘制系统发育树。基于IBV-N和S1基因序列的系统发育树显示，2016年哈萨流行的IBV毒株与来自台湾和意大利的一些毒株具有高度同源性。同时，基于IBV-S1序列对这些毒株进行分组显示，哈萨目前流行的IBV毒株与来自台湾的毒株同属于Gr.I.7。
我们的结果证实，尽管对该病毒大量使用了疫苗，但IBV仍在哈萨的鸡群中持续传播。
