Al-Mubarak Abdullah I A, Al-Kubati Anwar A G
Department of Microbiology, College of Veterinary Medicine, King Faisal University, Hofuf, Saudi Arabia.
Department of Botany and Microbiology, College of Sciences, King Saud University, Saudi Arabia.
Vet Med Int. 2020 Mar 31;2020:6037893. doi: 10.1155/2020/6037893. eCollection 2020.
Avian infectious bronchitis virus (IBV) is an evolving and dynamic virus that causes major economic losses for the poultry industry worldwide. Continuous evolution and emergence of new variants of this virus are the major challenges for controlling the disease with routine vaccination. Successful vaccination usually requires the use of a homologous vaccine, which in turn necessitates continuous investigation of the circulating strains. Herein, we performed a reverse transcriptase-polymerase chain reaction- (RT-PCR-) based investigation in broiler chicken flocks of the Eastern Region of Saudi Arabia. IBV was detected in 36.5% of the tested flocks (42 out of 115) from January 2012 to March 2014. Direct sequencing of hypervariable region-3 (HVR-3) of the Spike (S)-1 gene was performed, followed by phylogenetic analysis to determine the circulating IBV genotypes. Four lineages appear to coexist in this region, including the GI-13 or 4/91 IBV (31%), GI-16 or CK/CH/LDL/97I IBV (28.6%), GI-1 or Mass IBV (19%), and GI-23 or Middle East IBV (21.4%). The latter lineage include two subgroups: IS/720/99 IBV (16.7%) and IS/Variant2/98 IBV (4.7%). Some of the detections made in the 4/91 and Mass lineages are expected to belong to the vaccine strains. Lineages without a homologous vaccine in use (CK/CH/LDL/97I and Middle East) represent 50% of the isolates recovered in this study. Based on identity with the vaccine sequences, field observations, and frequent detection, these two lineages appear to be out of coverage of the IBV vaccines used in Saudi Arabia. This is the first time to identify Middle East lineage (IS/720/99 IBV and IS/Variant2/98 IBV) in the Eastern Region of Saudi Arabia.
禽传染性支气管炎病毒（IBV）是一种不断演变的动态病毒，给全球家禽业造成重大经济损失。该病毒新变种的持续演变和出现是通过常规疫苗接种控制该病的主要挑战。成功的疫苗接种通常需要使用同源疫苗，这反过来又需要持续调查流行毒株。在此，我们对沙特阿拉伯东部地区的肉鸡群进行了基于逆转录酶-聚合酶链反应（RT-PCR）的调查。在2012年1月至2014年3月期间，在36.5%的受测鸡群（115个中的42个）中检测到了IBV。对刺突（S）-1基因的高变区3（HVR-3）进行了直接测序，随后进行系统发育分析以确定流行的IBV基因型。该地区似乎有四个谱系共存，包括GI-13或4/91 IBV（31%）、GI-16或CK/CH/LDL/97I IBV（28.6%）、GI-1或Mass IBV（19%）以及GI-23或中东IBV（21.4%）。后一个谱系包括两个亚组：IS/720/99 IBV（16.7%）和IS/Variant2/98 IBV（4.7%）。在4/91和Mass谱系中进行的一些检测预计属于疫苗株。未使用同源疫苗的谱系（CK/CH/LDL/97I和中东）占本研究中分离株的50%。基于与疫苗序列的一致性、现场观察和频繁检测，这两个谱系似乎不在沙特阿拉伯使用的IBV疫苗覆盖范围内。这是首次在沙特阿拉伯东部地区鉴定出中东谱系（IS/720/99 IBV和IS/Variant2/98 IBV）。
