Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Ridebanevej 3, DK-1870 Frederiksberg C, Denmark.
Vet Microbiol. 2010 Jul 29;144(1-2):203-9. doi: 10.1016/j.vetmic.2009.12.038. Epub 2010 Jan 11.
During a 2-month period a newly repopulated Danish pig herd experienced an increase in numbers of stillborn and mummies, caused by porcine circovirus type 2 (PCV2) associated reproductive failure. Based on recordings of data over time, the progression of the clinical outbreak was studied and the diagnostic value of different techniques was evaluated. Foetal hearts (38 cases and 13 controls) were examined by immunohistochemistry (IHC) and real-time polymerase chain reaction (PCR) for the detection of PCV2; and total immunoglobulin G (IgG) was measured in pleura cavity fluid. PCV2 IHC was positive in 14/38 of the case foetuses, which were delivered during a 9 days period early in the outbreak. On the basis of the results obtained by IHC and PCR, the foetuses were divided into 3 categories: PCV2 negative; moderately positive (10(4) to 10(7) copies per 500 ng DNA); and massively positive for PCV2 (>10(7) copies per 500 ng DNA). All control- and IHC positive foetuses were included in the negative and massively positive groups, respectively. Ten case foetuses had elevated IgG levels, which did not correlate with the IHC or PCR results. Based on the clustering of the IHC positive foetuses, it is suggested that IHC only is suited for diagnosing acute stages of reproductive failure, whereas quantitative PCR can be used as a sensitive diagnostic method within a wider time span. It seems that IgG measurements are unpredictable as indication of intrauterine infection with PCV2.
在两个月的时间里，一个新重新繁殖的丹麦猪群经历了死胎和木乃伊数量的增加，这是由猪圆环病毒 2 型（PCV2）引起的繁殖失败。基于随时间记录的数据，研究了临床暴发的进展，并评估了不同技术的诊断价值。通过免疫组织化学（IHC）和实时聚合酶链反应（PCR）检测胎儿心脏（38 例和 13 例对照）中的 PCV2；并测量胸腔液中的总免疫球蛋白 G（IgG）。在暴发早期的 9 天内，PCV2 IHC 在 38 例病例胎儿中的 14 例中呈阳性。根据 IHC 和 PCR 的结果，将胎儿分为 3 类：PCV2 阴性；中度阳性（10（4）至 10（7）拷贝/500ng DNA）；和 PCV2 大量阳性（>10（7）拷贝/500ng DNA）。所有对照和 IHC 阳性的胎儿分别包含在阴性和大量阳性组中。10 例病例胎儿 IgG 水平升高，但与 IHC 或 PCR 结果无关。基于 IHC 阳性胎儿的聚类，建议 IHC 仅适用于诊断繁殖失败的急性阶段，而定量 PCR 可在更广泛的时间范围内用作敏感的诊断方法。似乎 IgG 测量作为 PCV2 宫内感染的指示是不可预测的。
