Porcine circovirus 2 (PCV2) and porcine circovirus 3 (PCV3) are considered a threat to the pig industry due to their association with growth retardation and reproductive disorders. In this study, we developed a multiplex real-time PCR (qPCR) assay for simultaneous detection of PCV2 and PCV3 and used it to investigate the epidemiology of PCV2 and PCV3 at different stages of pig production. The sensitivity of the multiplex qPCR was 4.32 × 10¹copies/µL for PCV2 and 1.01 × 10¹copies/µL for PCV3, and the coefficient of variation was less than 1%. The correlation coefficients (R²) of the standard curves were all greater than 0.990. Out of 1241 samples tested, nine (0.73%) were positive for PCV2, 209 (16.84%) for PCV3, and three (0.24%) for both. PCV2 was detected in saliva from asymptomatic gilts on one farm, and PCV3 was detected in all sample types except semen at all production stages on all of the farms where samples were collected. The main sample types that tested positive were saliva (23.19%, 77/322), blood (17.80%, 102/573), saliva/blood mixture (18.75%, 9/48), and pigpen swabs (32.14%, 9/28). Viral loads ranged from 10^3.9 to 10^8.2 copies/mL. Gilts (37.85%, 81/214) and grow-finish pigs (42.25%, 30/71) were the main asymptomatic PCV3 carriers. Piglets (16.67%, 3/18) and nursery pigs (22.73%, 5/22) were the main symptomatic PCV3 carriers. The assay described here is a practical and sensitive diagnostic technique for identification and monitoring of PCV2 and PCV3 infections and can provide new information on the epidemiology of PCV2 and PCV3 that can be applied for developing effective prevention and control strategies.

Keywords: Epidemiology; Multiplex quantitative PCR; Pig production; Porcine circovirus 2; Porcine circovirus 3; Swine.

© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.

猪圆环病毒2型（PCV2）和猪圆环病毒3型（PCV3）由于与生长迟缓和生殖障碍相关，被认为是威胁养猪业的病原。本研究开发了一种用于同时检测PCV2和PCV3的多重实时PCR（qPCR）检测试剂盒，并利用该试剂盒调查了不同生产阶段猪群中PCV2和PCV3的流行病学情况。该多重qPCR的灵敏度为PCV2 4.32×10^1拷贝数/µL，PCV3 1.01×10^1拷贝数/µL，变异系数小于1%。标准曲线的相关系数（R²）均大于0.990。在检测的1241个样本中，有九个（0.73%）为PCV2阳性，209个（16.84%）为PCV3阳性，三个（0.24%）同时为两种病毒阳性。PCV2仅在一个农场从无症状母猪的唾液样本中检测到，而PCV3在除精液之外的所有生产阶段、所有采样地点的所有样本类型中均有检出。主要呈现阳性的样本类型包括：唾液（23.19%，77/322）、血液（17.80%，102/573）、唾液和血液混合物（18.75%，9/48）以及猪舍拭子（32.14%，9/28）。病毒载量范围从10^3.9到10^8.2拷贝数/mL。后备母猪（37.85%，81/214）和育肥猪（42.25%，30/71）是主要的无症状PCV3携带者，而仔猪（16.67%，3/18）和保育猪（22.73%，5/22）则是主要的症状性PCV3携带者。本文所述的方法是一种实用且灵敏的诊断技术，用于鉴定和监测PCV2和PCV3感染，并能为开发有效的预防和控制策略提供新的流行病学信息。

关键词： 流行病学；多重定量PCR；猪生产；猪圆环病毒2型；猪圆环病毒3型；猪。