Veterinary Hospital, Al-Diwaniyah, Al-Qadisiyah, Iraq.
Department of Internal and Preventive Medicine, College of Veterinary Medicine, University of Al-Qadisiyah, Al-Qadisiyah, Iraq.
Open Vet J. 2022 Mar-Apr;12(2):264-272. doi: 10.5455/OVJ.2022.v12.i2.15.
Ovine pulmonary adenocarcinoma (OPA), caused by Jaagsiekte sheep retrovirus (JSRV), is a contagious neoplastic disease in sheep characterized by chronic respiratory signs, inducing the transformation of secretory epithelial cells of the distal respiratory tract.
To perform clinical, epidemiological, and molecular studies with evaluation of some predisposing factors at the herd level of OPA infection in sheep in Al-Qadisiyah Province, Iraq.
The first step of the study was undertaken to evaluate the clinical cases of OPA in naturally infected sheep and correlation with observing respiratory signs. Seventy-five sheep with chronic respiratory signs were examined clinically, and by molecular and sequences analysis. The second step was the epidemiological part that was carried out on 195 randomly selected animals from 30 flocks, with the prevalence rate based on PCR; sex, age, and size of flocks were assessed, as well as macroscopic and microscopic features of the neoplastic lung. Deep nasal swabs and nasal secretion were collected from all animals. RNA extraction and RT-PCR were also carried out.
The results showed that 12 (16%) samples were positive for OPA, based on env gene-specific primers. Nucleotide sequences of partial 545 bp of the env gene showed (0.07-0.12) variations from global strains presented in the NCBI database. The prevalence rate of OPA was 21/195 (10.76%) with PCR. The epidemiological factors analysis showed that there was no effect of sex and herd size on the prevalence rates ( ≥ 0.01), whereas age was significantly affected and the age of 2-4 years was more susceptible ( ≥ 0.01). Gross and microscopic examinations were discussed with the confirmation of an OPA infection.
The current study provides useful data about the clinical and epidemiological features of JSRV that is circulating in sheep of Iraq, and concludes that epidemiological studies and disease control may require multi-diagnostic assays.
绵羊肺腺瘤病（OPA）由绵羊肺腺瘤反转录病毒（JSRV）引起，是一种传染性肿瘤疾病，以绵羊慢性呼吸道症状为特征，导致远端呼吸道分泌上皮细胞转化。
在伊拉克济加尔省的绵羊群体水平上进行 OPA 感染的临床、流行病学和分子研究，并评估一些易感性因素。
研究的第一步是评估自然感染绵羊中的 OPA 临床病例，并与观察到的呼吸道症状相关联。对 75 只具有慢性呼吸道症状的绵羊进行临床检查，并进行分子和序列分析。第二步是流行病学部分，对 30 个羊群中随机选择的 195 只动物进行了评估，根据 PCR 确定流行率；评估了性别、年龄和羊群规模，以及肿瘤肺部的宏观和微观特征。从所有动物中采集深部鼻腔拭子和鼻分泌物。还进行了 RNA 提取和 RT-PCR。
结果表明，基于 env 基因特异性引物，有 12 份（16%）样本呈 OPA 阳性。env 基因的部分 545 个核苷酸序列显示与 NCBI 数据库中呈现的全球株有（0.07-0.12）的变异。OPA 的流行率为 195 份中的 21 份（10.76%），PCR 阳性。流行病学因素分析表明，性别和羊群规模对流行率没有影响（≥0.01），而年龄有显著影响，2-4 岁的年龄更易感（≥0.01）。对大体和显微镜检查进行了讨论，并确认了 OPA 感染。
本研究提供了有关在伊拉克绵羊中循环的 JSRV 的临床和流行病学特征的有用数据，并得出结论，流行病学研究和疾病控制可能需要多诊断检测。
