Haque Mohammad Aynul, Sadekuzzaman Mohammad, Haque Md Enamul, Parvin Mst Kohinoor, Kamal Md Mostofa, Hayat Sajedul, Islam Md Ariful, Khatun Mst Minara, Siddique Mahbubul Pratik, Nahar Sham Soun, Khasruzzaman A K M, Hossain Muhammud Tofazzal, Islam Md Alimul
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh, Bangladesh.
Central Disease Investigation Laboratory, Department of Livestock Services, Dhaka, Bangladesh.
J Adv Vet Anim Res. 2024 Jun 9;11(2):408-417. doi: 10.5455/javar.2024.k790. eCollection 2024 Jun.
Newcastle disease virus genotype VII (NDV-GVII), an extremely infectious pathogen, has been causing severe economic consequences for the chicken industry. The current study aimed to isolate and characterize NDV-GVII from commercial chickens in Bangladesh during a recent outbreak.
From clinically suspected chickens from 70 commercial poultry farms, a total of 420 samples (trachea, lungs, and brain tissue) were collected. The samples were cultivated in 9-10 day-old seronegative embryonated chicken eggs (ECEs) after evaluating them using the rapid Newcastle disease virus (NDV) antigen detection kit. The hemagglutination (HA) inhibition test, agar gel immune diffusion (AGID) test, molecular detection by reverse transcription-polymerase chain reaction (RT-PCR), and phylogenetic studies using gene sequences of fusion (F) protein. The HA pattern of isolated NDV was determined using different avian and mammalian red blood cells (RBCs). The pathogenicity of the isolated virus was evaluated using mean death time (MDT), intravenous pathogenicity index (IVPI), and intracerebral pathogenicity index (ICPI).
The study found 87 NDV samples positive using the rapid NDV Ag detection kit and then 60 positives for virus isolation in ECEs. All 60 isolates were positive for NDV by HI, AGID, and RT-PCR. Phylogenetic tree analysis indicated that recent NDV isolates belong to genotype VII and exhibit a similarity of 99.7%-98.5% with isolates from Bangladesh, Iran, and India. The new isolates, identified as velogenic strains of NDV, possess an F protein cleavage site with -R-T-K-R-F- amino acid motifs. The isolated NDV showed diversified HA activity while using RBCs from birds and mammals. The results of ICPI, IVPI, and MDT indicated that the recent NDV isolates were very virulent.
This study concluded that NDV-GVII is prevalent in commercial poultry farms in Bangladesh.
新城疫病毒VII型（NDV-GVII）是一种极具传染性的病原体，给养鸡业带来了严重的经济损失。本研究旨在从孟加拉国近期一次疫情中的商业鸡群中分离并鉴定NDV-GVII。
从70个商业家禽养殖场临床疑似感染的鸡中，共采集了420份样本（气管、肺和脑组织）。使用快速新城疫病毒（NDV）抗原检测试剂盒对样本进行评估后，将其接种于9-10日龄的血清阴性鸡胚（ECE）中进行培养。采用血凝（HA）抑制试验、琼脂凝胶免疫扩散（AGID）试验、逆转录-聚合酶链反应（RT-PCR）进行分子检测，并利用融合（F）蛋白基因序列进行系统发育研究。使用不同的禽类和哺乳动物红细胞（RBC）确定分离出的NDV的HA模式。使用平均死亡时间（MDT）、静脉致病性指数（IVPI）和脑内致病性指数（ICPI）评估分离病毒的致病性。
本研究使用快速NDV抗原检测试剂盒发现87份NDV样本呈阳性，随后在ECE中分离出60株病毒阳性样本。所有60株分离株通过血凝抑制试验、琼脂凝胶免疫扩散试验和RT-PCR检测均为NDV阳性。系统发育树分析表明，近期的NDV分离株属于VII型，与来自孟加拉国、伊朗和印度的分离株相似度为99.7%-98.5%。新分离株被鉴定为NDV的速发型毒株，其F蛋白裂解位点具有-R-T-K-R-F-氨基酸基序。使用禽类和哺乳动物的红细胞时，分离出的NDV显示出多样化的HA活性。ICPI、IVPI和MDT的结果表明，近期的NDV分离株具有很强的毒性。
本研究得出结论，NDV-GVII在孟加拉国的商业家禽养殖场中普遍存在。
