Kadhim Hakeem Jawad, Shlaga Abbas Kamil, Ali Safaa Hussein
Department of Microbiology, College of Veterinary Medicine and Surgery, Shatrah University, Shatrah, Thi-Qar, Iraq.
Department of Physiology, College of Veterinary Medicine and Surgery, Shatrah University, Shatrah, Thi-Qar, Iraq.
Open Vet J. 2024 Nov;14(11):2817-2826. doi: 10.5455/OVJ.2024.v14.i11.10. Epub 2024 Nov 30.
In poultry, despite intense vaccination programs for prevention of Newcastle disease (ND), the ND infection still affects, causing high mortality in most vaccinated flocks.
This study aimed to determine whether the genetic material of the ND virus has changed and has become incompatible with the vaccines used in Iraq.
Real-time PCR was used to analyze genetic variation in the fusion (F) and haemaggluatination neuraminidase (HN) genes, as well as mRNA expression changes in inflammatory biomarkers, including C-reactive protein (CRP), interleukin 6, interleukin-1 beta (IL-6, IL-1β), and gamma interferon (IFN-γ).
Although the vaccine was initially used to vaccinate broiler flocks against NDV, we noticed a variety of respiratory, digestive, and nervous signs in many flocks throughout Thi-Qar Province of Iraq. Furthermore, the infected birds showed typical postmortem lesions, such as mottled spleen, proventricular hemorrhages, and cecal tonsil hemorrhages. Blood, liver, and tracheal swabs were collected from infected and healthy broilers aged 3-5 weeks old. NDV infection was initially confirmed using the NDV antigen rapid test, which showed positive results in 52 of the 60 suspected samples (86.66%). However, mean antibody levels in ND-infected birds were significantly lower than those in healthy birds. In contrast, mRNA levels of bio-inflammatory genes were increased, indicating that the birds were infected with the virus and that there was inflammation in the body. To confirm NDV infection, the F and HN genes were sequenced. F gene alignment against NCBI nucleotide sequence data showed that the isolate had 94.68% similarity with the avian orthoavulavirus1 isolate Ph/IR/AMMM116/2018 fusion protein gene. While HN gene alignment showed 95.36% similarity with the NDV strain hemagglutinin-neuraminidase gene.
ND infection resulted in a decrease in antibody titers and an increase in the expression of inflammatory biomarkers genes. The findings suggested that alterations in the nucleic acids of the NDV strains could be the main cause of potential outbreaks in Iraq, and that vaccines appeared to be incompatible with the circulating strain. Thus, it is recommended that, besides the rapid detection test, molecular methods should always be considered in endemic areas or outbreak situations.
在家禽中，尽管实施了针对新城疫（ND）的强化疫苗接种计划，但ND感染仍有影响，导致大多数接种疫苗的鸡群死亡率很高。
本研究旨在确定ND病毒的遗传物质是否发生了变化，是否与伊拉克使用的疫苗不兼容。
采用实时荧光定量PCR分析融合（F）基因和血凝神经氨酸酶（HN）基因的遗传变异，以及炎症生物标志物（包括C反应蛋白（CRP）、白细胞介素6、白细胞介素-1β（IL-6、IL-1β）和γ干扰素（IFN-γ））的mRNA表达变化。
尽管最初使用该疫苗对肉鸡群进行新城疫病毒（NDV）免疫接种，但我们在伊拉克济加尔省的许多鸡群中注意到了各种呼吸道、消化道和神经症状。此外，感染的鸡表现出典型的死后病变，如脾脏斑驳、腺胃出血和盲肠扁桃体出血。从3至5周龄的感染和健康肉鸡中采集血液、肝脏和气管拭子。最初使用NDV抗原快速检测法确认NDV感染，60份疑似样本中有52份呈阳性结果（86.66%）。然而，ND感染鸡的平均抗体水平显著低于健康鸡。相反，生物炎症基因的mRNA水平升高，表明鸡感染了病毒且体内存在炎症。为确认NDV感染，对F基因和HN基因进行了测序。与NCBI核苷酸序列数据的F基因比对显示，该分离株与禽正副黏病毒1分离株Ph/IR/AMMM116/2018融合蛋白基因的相似性为9
