Barboza-Solis Catalina, Contreras Ana Perez, Palomino-Tapia Victor A, Joseph Tommy, King Robin, Ravi Madhu, Peters Delores, Fonseca Kevin, Gagnon Carl A, van der Meer Frank, Abdul-Careem Mohamed Faizal
Faculty of Veterinary Medicine, University of Calgary, Health Research Innovation Center 2C53, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
Animal Health Centre, Ministry of Agriculture, Abbotsford, BC V3G 2M3, Canada.
Animals (Basel). 2020 Sep 11;10(9):1634. doi: 10.3390/ani10091634.
Infectious laryngotracheitis virus (ILTV) causes an acute upper respiratory disease in chickens called infectious laryngotracheitis (ILT). Live attenuated vaccines are effective in disease control; however, they have residual virulence, which makes them able to replicate, cause disease and revert to the original virulent form. Information is scarce on the molecular nature of ILTV that is linked to ILT in Canada. This study aims to determine whether isolates originating from ILT cases in Western Canada are a wild type or vaccine origin. Samples submitted for the diagnosis of ILT between 2009-2018 were obtained from Alberta (AB, = 46) and British Columbia (BC, = 9). For genotyping, a Sanger sequencing of open reading frame (ORF) a and b was used. A total of 27 from AB, and 5 from BC samples yielded a fragment of 1751 base pairs (bp). Three of the BC samples classified as group IV (CEO vaccine strains) and 2 as group V (CEO revertant). Of the AB samples, 22 samples clustered with group V, 3 with group VI (wild type), and 2 with group VII, VIII, and IX (wild type). Overall, 17 non-synonymous single nucleotide polymorphisms (SNPs) were detected. Further studies are underway to ascertain the virulence and transmission potential of these isolates.
传染性喉气管炎病毒（ILTV）可在鸡群中引发一种名为传染性喉气管炎（ILT）的急性上呼吸道疾病。减毒活疫苗对疾病防控有效；然而，它们具有残余毒力，这使其能够复制、引发疾病并回复到原始的强毒株形式。在加拿大，关于与ILT相关的ILTV分子特性的信息较为匮乏。本研究旨在确定源自加拿大西部ILT病例的分离株是野生型还是疫苗来源。2009年至2018年间提交用于ILT诊断的样本取自艾伯塔省（AB，n = 46）和不列颠哥伦比亚省（BC，n = 9）。对于基因分型，采用了开放阅读框（ORF）a和b的桑格测序法。来自AB的27个样本以及来自BC的5个样本产生了一个1751个碱基对（bp）的片段。BC的3个样本归类为IV组（CEO疫苗株），2个归类为V组（CEO回复株）。在AB样本中，22个样本聚集在V组，3个聚集在VI组（野生型），2个聚集在VII、VIII和IX组（野生型）。总体而言，检测到17个非同义单核苷酸多态性（SNP）。正在进行进一步研究以确定这些分离株的毒力和传播潜力。
