Blacker H P, Kirkpatrick N C, Rubite A, O'Rourke D, Noormohammadi A H
School of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia.
Aust Vet J. 2011 Mar;89(3):89-94. doi: 10.1111/j.1751-0813.2010.00665.x.
Over the past 3 years, numerous outbreaks of infectious laryngotracheitis (ILT) have occurred in poultry in Australia. The objectives of this study were to identify the viral strains involved in the recent outbreaks and to determine possible epidemiological links between these outbreaks.
A combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses of several genes of the ILT virus was used to identify genetic differences in field/vaccine ILT virus isolates. In a previous study, these procedures had demonstrated five classes (1-5) in Australia.
Analysis of 92 field ILT viruses demonstrated four new classes: 6, 7, 8 and 9. Class 6 was responsible for four outbreaks in one Victorian broiler company and demonstrated to be distinct from other Australian strains of ILT. Class 7 was the Nobilis ILT vaccine (Intervet Pty Ltd). Class 8 was responsible for the majority of the outbreaks in New South Wales and was phylogenetically close to class 7. On one occasion, classes 7 and 8 were identified in an outbreak on a Victorian farm that had used the Nobilis ILT vaccine. Class 9, also phylogenetically close to classes 7 and 8, was found only in New South Wales. The previously identified class 2 was also found to be responsible for a large number of outbreaks, mainly in Victoria.
The results demonstrate that, epidemiologically, most outbreaks of ILT in New South Wales are unrelated to those in Victoria and suggest a link between classes 8 and 9 and the Nobilis ILT vaccine (class 7).
在过去3年中，澳大利亚家禽中发生了多起传染性喉气管炎（ILT）疫情。本研究的目的是确定近期疫情中涉及的病毒株，并确定这些疫情之间可能的流行病学联系。
采用聚合酶链反应（PCR）和限制片段长度多态性（RFLP）分析相结合的方法，对ILT病毒的几个基因进行分析，以确定田间/疫苗ILT病毒分离株的遗传差异。在之前的一项研究中，这些程序在澳大利亚确定了五个类别（1-5）。
对92株田间ILT病毒的分析显示了四个新类别：6、7、8和9。第6类导致了一家维多利亚州肉鸡公司的四起疫情，并且被证明与澳大利亚其他ILT毒株不同。第7类是诺比利斯ILT疫苗（英特威私人有限公司）。第8类导致了新南威尔士州的大部分疫情，并且在系统发育上与第7类接近。有一次，在维多利亚州一个使用了诺比利斯ILT疫苗的农场爆发的疫情中发现了第7类和第8类。第9类在系统发育上也与第7类和第8类接近，仅在新南威尔士州发现。先前确定的第2类也被发现导致了大量疫情，主要发生在维多利亚州。
结果表明，从流行病学角度来看，新南威尔士州的大多数ILT疫情与维多利亚州的疫情无关，并表明第8类和第9类与诺比利斯ILT疫苗（第7类）之间存在联系。
