Athanasiou Labrini V, Kantere Maria C, Kyriakis Constantinos S, Pardali Dimitra, Adamama Moraitou Katerina, Polizopoulou Zoe S
1 Department of Medicine, Faculty of Veterinary Medicine, University of Thessaly , Karditsa, Greece .
2 Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia , Athens, Georgia .
Viral Immunol. 2018 Apr;31(3):272-275. doi: 10.1089/vim.2017.0101. Epub 2017 Nov 29.
Canine distemper is a common and potentially lethal multisystemic disease caused by the Canine distemper virus (CDV). We evaluated the diagnostic performance of direct immunofluorescent assay (FA) and cytology to detect CDV antigen in conjunctival cells compared with an established polymerase chain reaction (PCR) detection assay used as a gold standard for CDV diagnosis. Samples were collected from 57 young dogs presenting with central nervous system signs compatible with distemper disease. Exfoliative epithelial cells were collected from the right and left conjunctiva of each animal using nylon-bristled cytobrushes for cytology and cotton swabs for FA and PCR. For the direct FA, samples were stained with anti-CDV polyclonal antiserum conjugated to fluorescein isothiocyanate and imaged using a fluorescent microscope. Out of 57 dogs tested, 19 were PCR positive (15 positive in direct FA and 4 positive in cytology, including one that was negative by PCR), whereas 37 dogs were negative in all methods. A good agreement was observed between the FA and PCR, with a κ-value of 0.833 (95% CI: 0.678-0.989). Meanwhile, there was poor agreement between cytology and PCR (κ-value of 0.164; 95% CI: -0.045 to 0.373) and a fair agreement between FA and cytology (κ-value of 0.231; 95% CI: -0.026 to 0.487). Our results indicated a poor performance of cytology for the detection of CDV antigen. In contrast, FA is a 100% specific and an adequately sensitive assay (sensitivity: 78.95%, negative likelihood ratio: 0.21, 95% CI: 0.09-0.50) for antemortem diagnosis of canine distemper.
犬瘟热是由犬瘟热病毒（CDV）引起的一种常见且可能致命的多系统疾病。我们评估了直接免疫荧光法（FA）和细胞学检查在检测结膜细胞中CDV抗原方面的诊断性能，并与用作CDV诊断金标准的既定聚合酶链反应（PCR）检测方法进行了比较。样本取自57只出现与犬瘟热疾病相符的中枢神经系统症状的幼犬。使用尼龙刷毛细胞刷从每只动物的左右结膜收集脱落的上皮细胞用于细胞学检查，使用棉签收集用于FA和PCR检测的样本。对于直接FA检测，样本用与异硫氰酸荧光素偶联的抗CDV多克隆抗血清染色，并使用荧光显微镜成像。在57只受试犬中，19只PCR检测呈阳性（15只直接FA检测呈阳性，4只细胞学检查呈阳性，其中1只PCR检测为阴性），而37只犬在所有检测方法中均为阴性。FA检测和PCR检测之间观察到良好的一致性，κ值为0.833（95%置信区间：0.678 - 0.989）。同时，细胞学检查与PCR检测之间的一致性较差（κ值为0.164；95%置信区间：-0.045至0.373），FA检测与细胞学检查之间的一致性一般（κ值为0.231；95%置信区间：-0.026至0.487）。我们的结果表明细胞学检查在检测CDV抗原方面表现不佳。相比之下，FA检测是一种100%特异性且灵敏度足够的检测方法（灵敏度：78.95%，阴性似然比：0.21，95%置信区间：0.09 - 0.50），可用于犬瘟热的生前诊断。
