RESULTS: Nasal swabs of suckling piglets and nursery pigs resulted in a higher odds to detect swIAV (p < 0.001) and to identify swIAV subtypes by RT-qPCR (p < 0.05) compared to nasal swabs of sows. In suckling piglets, significant higher rates of swIAV detection could be observed for nasal swabs (p = 0.007) and sow udder skin wipes (p = 0.036) compared to contact wipes. In the nursery, group sampling specimens were significantly more often swIAV positive compared to individual samples (p < 0.01), with exception of the comparison between contact wipes and nasal swabs (p = 0.181). However, in general nasal swabs were more likely to have Ct-value < 32 and thus, to be suitable for subtyping by RT-qPCR compared to dust wipes, contact wipes, udder skin wipes and tracheobronchial swabs (p < 0.05). Interestingly, different subtypes were found in different age groups as well as in different specimens in the same holding.
CONCLUSIONS: Although population-based specimens are highly effective for swIAV monitoring, nasal swabs are still the preferable sampling material for the surveillance of on-farm circulating strains due to significantly higher virus loads. Remarkably, sampling strategies should incorporate suckling piglets and different age groups within the nursery to cover as many as possible of the on-farm circulating strains.
结果:与母猪的鼻拭子相比,乳猪和保育猪的鼻拭子检测swIAV(p<0.001)和通过RT-qPCR鉴定swIAV亚型(p<0.05)的几率更高。在哺乳仔猪中,与接触湿巾相比,鼻拭子(p=0.007)和母猪乳房皮肤湿巾(p=0.036)的swIAV检测率明显更高。在托儿所,与单个样本相比,整群抽样样本明显更容易出现swIAV阳性(p<0.01),除了接触湿巾和鼻拭子之间的比较(p=0.181)。然而,一般来说,鼻拭子更有可能具有<32的Ct值,因此,与防尘湿巾相比,适合通过RT-qPCR进行分型,接触湿巾,乳房皮肤湿巾和气管支气管拭子(p<0.05)。有趣的是,不同的亚型在不同的年龄组,以及在不同的标本在同一持有。
结论:尽管基于人群的样本对于SwIAV监测非常有效,由于病毒载量明显较高,鼻拭子仍然是监测农场流行毒株的首选取样材料.值得注意的是,采样策略应将哺乳仔猪和不同年龄段的仔猪纳入苗圃中,以覆盖尽可能多的农场循环菌株。