Department of Medical Sciences, Shelter Medicine Program, University of Wisconsin, Madison, Wisconsin, United States of America.
Wisconsin Veterinary Diagnostic Laboratory, Virology, University of Wisconsin, Madison, Wisconsin, United States of America.
PLoS One. 2023 Jan 20;18(1):e0280186. doi: 10.1371/journal.pone.0280186. eCollection 2023.
Canine distemper virus remains an important source of morbidity and mortality in animal shelters. RT-PCR is commonly used to aid diagnosis and has been used to monitor dogs testing positive over time to gauge the end of infectious potential. Many dogs excrete viral RNA for prolonged periods which has complicated disease management. The goal of this retrospective study was to describe the duration and characteristics of viral RNA excretion in shelter dogs with naturally occurring CDV and investigate the relationship between that viral RNA excretion and infectious potential using virus isolation data. Records from 98 different humane organizations with suspect CDV were reviewed. A total of 5,920 dogs were tested with 1,393; 4,452; and 75 found to be positive, negative, or suspect on RT-PCR respectively. The median duration of a positive test was 34 days (n = 325), and 25% (82/325) of the dogs still excreting viral RNA after 62 days of monitoring. Virus isolation was performed in six dogs who were RT-PCR positive for > 60 days. Infectious virus was isolated only within the first two weeks of monitoring at or around the peak viral RNA excretion (as detected by the lowest cycle threshold) reported for each dog. Our findings suggest that peak viral RNA excretion and the days surrounding it might be used as a functional marker to gauge the end of infectious risk. Clarifying the earliest point in time when dogs testing positive for canine distemper by RT-PCR can be considered non-contagious will improve welfare and lifesaving potential of shelters by enabling recovered dogs to be cleared more quickly for live release outcomes.
犬瘟热病毒仍然是动物收容所发病率和死亡率的重要来源。实时聚合酶链反应（RT-PCR）常用于辅助诊断，并用于监测随时间推移呈阳性的犬只，以评估其传染性潜力的结束时间。许多犬只长时间排出病毒 RNA，这增加了疾病管理的难度。本回顾性研究的目的是描述自然感染犬瘟热病毒的犬只中病毒 RNA 排出的持续时间和特征，并利用病毒分离数据研究该病毒 RNA 排出与传染性潜力之间的关系。对来自 98 个不同人道组织的可疑犬瘟热病毒记录进行了回顾。共有 5920 只犬接受了检测，其中 1393 只、4452 只和 75 只犬分别通过 RT-PCR 检测呈阳性、阴性或可疑。阳性检测的中位数持续时间为 34 天（n = 325），在监测 62 天后仍有 25%（82/325）的犬只在排出病毒 RNA。对 RT-PCR 检测呈阳性且持续时间超过 60 天的 6 只犬进行了病毒分离。仅在监测的头两周内，在每只犬报告的病毒 RNA 排出量最高（由最低循环阈值检测到）的周围或附近分离到了传染性病毒。我们的研究结果表明，病毒 RNA 排出峰值及其周围的时间可能被用作衡量传染性风险结束的功能标志物。通过明确 RT-PCR 检测呈阳性的犬只最早何时可被认为是非传染性的，将有助于提高收容所的福利和拯救生命的潜力，使康复犬能够更快地获得释放结果。
