2021 - 2022年期间从孟加拉国商业蛋鸡中分离出的传染性喉气管炎病毒的特性分析

Characterization of infectious laryngotracheitis virus isolated from commercial layer chickens in Bangladesh during the year 2021-2022.

作者信息

Kamal Md Mostofa, Sadekuzzaman Mohammad, Parvin Kohinoor, Haque Md Enamul, Hayat Sajedul, Islam Md Ariful, Khatun Mst Minara, Siddique Mahbubul Pratik, Nahar Sham Soun, Khasruzzaman A K M, Hossain Muhammud Tofazzal, Islam Md Alimul

机构信息

Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh, Bangladesh.

Central Disease Investigation Laboratory, Department of Livestock Services, Dhaka, Bangladesh.

出版信息

J Adv Vet Anim Res. 2024 Jun 9;11(2):398-407. doi: 10.5455/javar.2024.k789. eCollection 2024 Jun.

DOI:10.5455/javar.2024.k789

PMID:39101088

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11296171/

Abstract

OBJECTIVE

Infectious laryngotracheitis virus (ILTV) is responsible for causing infectious laryngotracheitis (ILT), which is a rapidly spreading and extremely transmissible disease in chickens. The current research aims to isolate and characterize ILTV from layer chickens in Bangladesh.

MATERIALS AND METHODS

A total of 345 samples (trachea, larynx, and lungs) were collected from ILT-suspected dead and sick layer chickens of 32 ILT-suspected farms in three different outbreak districts (Gazipur, Tangail, and Mymensingh) of Bangladesh during the outbreak year 2021-2022. Rapid detection kits examined the samples for avian influenza virus (AIV) and Newcastle disease virus (NDV). ILTV-specific primers were used to screen 72 NDV- and AIV-negative samples by polymerase chain reaction (PCR). Using chorioallantoic membrane (CAM), the study isolated the ILT virus from 9 to 10-day-old seronegative embryonated chicken eggs (ECEs) using selected PCR-positive samples. The virus was confirmed using nucleotide sequencing, agar gel immunodiffusion test (AGIDT), viral neutralization test (VNT), and pathogenicity evaluations using mortality index for chicken embryos (MICEs) and intra-tracheal pathogenicity index (ITPI).

RESULTS

The results indicated that among the PCR-positive 10 samples, only two (Alim_ILT_1001 and Alim_ILT_1,000) were found positive using ECEs. There were two field isolates of ILTVs, as shown by the amplicon size of the ICP4 gene-based PCR. A phylogenetic study of the ICP4 gene revealed that the recent isolates have a close similarity with the ILTV isolates of Turkey, Bangladesh, and Australia. AGIDT revealed strong precipitation lines due to ILTV-specific antibodies reacting with field viruses, while VNT neutralized both isolates with conventional ILTV antibodies. The pathogenicity testing indicated that Alim_ILT_1001 had MICE and ITPI values of 0.77 and 0.63, whereas Alim_ILT_1,000 had 0.71 and 0.57.

CONCLUSION

Both the ILTV isolates have similarities with the isolates of Turkey, Bangladesh, and Australia, and they are highly virulent for chickens.

摘要

目的

传染性喉气管炎病毒（ILTV）可引发传染性喉气管炎（ILT），这是一种在鸡群中迅速传播且极易传染的疾病。当前研究旨在从孟加拉国蛋鸡中分离并鉴定ILTV。

材料与方法

在2021 - 2022年疫情爆发期间，从孟加拉国三个不同疫情爆发地区（加济布尔、坦盖尔和迈门辛哈）的32个疑似ILT养殖场的疑似ILT死亡和患病蛋鸡中，共采集了345份样本（气管、喉头和肺）。使用快速检测试剂盒检测样本中的禽流感病毒（AIV）和新城疫病毒（NDV）。利用ILTV特异性引物，通过聚合酶链反应（PCR）对72份NDV和AIV阴性样本进行筛选。该研究使用绒毛尿囊膜（CAM），利用选定的PCR阳性样本，从9至10日龄血清阴性的鸡胚（ECE）中分离出ILT病毒。通过核苷酸测序、琼脂凝胶免疫扩散试验（AGIDT）、病毒中和试验（VNT）以及使用鸡胚死亡率指数（MICE）和气管内致病性指数（ITPI）进行致病性评估来确认病毒。

结果

结果表明，在PCR阳性的10份样本中，仅两份（Alim_ILT_1001和Alim_ILT_1,000）通过鸡胚检测呈阳性。基于ICP4基因的PCR扩增片段大小显示有两种ILTV的野外分离株。对ICP4基因的系统发育研究表明，最近的分离株与土耳其、孟加拉国和澳大利亚的ILTV分离株有密切相似性。AGIDT显示，由于ILTV特异性抗体与野外病毒发生反应，出现了强沉淀线，而VNT用传统ILTV抗体中和了两种分离株。致病性测试表明，Alim_ILT_1001的MICE和ITPI值分别为0.77和0.63，而Alim_ILT_1,000的MICE和ITPI值分别为0.71和0.57。