National Research Center for Tropical and Transboundary Diseases (NRCTTD), Alzintan, Libya.
Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, University of Tripoli, Tripoli, Libya.
Open Vet J. 2024 Sep;14(9):2453-2462. doi: 10.5455/OVJ.2024.v14.i9.34. Epub 2024 Sep 30.
Since its discovery in 1926, Newcastle disease (ND) is still emerging in many avian species worldwide causing severe economic losses due to high mortality.
This article aims to discuss the challenge of virulent ND in poultry in Libya, focusing on recent outbreaks investigated in Alzintan, Alrayaina, Nalut, and Surman, cities located in the western region of Libya.
Clinical signs and lesions were recorded. Tissues, as well as tracheal and cloacal swabs, were collected. RNA extraction was performed for confirmation using PCR and sequencing.
Mortality, in general, reached 50%-100% in vaccinated flocks with respiratory distress, diarrhea, swelling of the face, and nasal discharges. Necropsy revealed severe hemorrhages in the proventriculus, necrosis, and hemorrhages in the intestine and cecal tonsils. All tested samples were positive for avian orthoavulavirus 1 (AOAV-1) using rRT-PCR and genetic analysis. The sequences obtained are referable to AOAV-1, which is the same strain in all tested samples. The amino acid sequences deduced from the cleavage site of the protein are referable to a velogenic strain of AOAV-1 belonging to genotype VII.2. The detected strains in the current study revealed 86%-91% identity with European isolates identified between 2020 and 2022 and isolates from Asia and Africa and 97% identity to the previous isolated Libyan strains in 2013 and 2016. It is slightly different by the presence of amino acid lycine at position 111 on the cleavage site of the F0 gene as compared to previous Libyan strains in which arginine was found in the same position. The nucleotide sequence at this position changed from (aga) in AOAV-1 strains of years 2013 and 2016 to (aag) of the year 2023.
ND remains a significant threat to the poultry industry in Libya. Therefore, there is an urgent need to conduct an epidemiological study with a representative number of samples from all regions of the country, alongside the implementation of an inactivated vaccine targeting genotype VII.
自 1926 年发现以来，新城疫（ND）仍在世界许多禽类物种中出现，导致高死亡率，造成严重的经济损失。
本文旨在讨论利比亚家禽中强毒 ND 的挑战，重点研究最近在 Alzintan、Alrayaina、Nalut 和 Surman 市爆发的疫情，这些城市位于利比亚西部地区。
记录临床症状和病变。采集组织以及气管和泄殖腔拭子。使用 PCR 和测序进行 RNA 提取以确认。
接种疫苗的禽类死亡率通常达到 50%-100%，伴有呼吸窘迫、腹泻、面部肿胀和鼻分泌物。剖检发现腺胃严重出血、坏死、肠道和盲肠扁桃体出血。所有测试样本均通过 rRT-PCR 和遗传分析对禽正黏病毒 1（AOAV-1）呈阳性。获得的序列可参考 AOAV-1，这是所有测试样本中的相同菌株。从 蛋白裂解位点推导的氨基酸序列可参考属于基因型 VII.2 的强毒 AOAV-1 株。本研究中检测到的菌株与 2020 年至 2022 年期间在欧洲鉴定的分离株以及亚洲和非洲的分离株具有 86%-91%的同一性，与 2013 年和 2016 年分离的利比亚先前分离株具有 97%的同一性。与之前在利比亚分离的菌株相比，该菌株在 F0 基因裂解位点的 111 位氨基酸略有不同，存在亮氨酸，而不是精氨酸。该位置的核苷酸序列从 2013 年和 2016 年的 AOAV-1 株的（aga）变为 2023 年的（aag）。
ND 仍然是利比亚家禽业的重大威胁。因此，迫切需要在该国所有地区进行具有代表性样本数量的流行病学研究，并实施针对基因型 VII 的灭活疫苗。
