Lillie-Jaschniski Kathrin, Lisgara Marina, Pileri Emanuela, Jardin Agnes, Velazquez Eduardo, Köchling Monika, Albin Michael, Casanovas Carlos, Skampardonis Vassilis, Stadler Julia
Ceva Tiergesundheit, Kanzlerstraße 4, 40472 Düsseldorf, Germany.
Ceva Hellas LLC, 16341 Athens, Greece.
Vet Sci. 2022 Jul 4;9(7):338. doi: 10.3390/vetsci9070338.
Swine influenza A virus (swIAV), which plays a major role in the porcine respiratory disease complex (PRDC), is eliminated from the respiratory tract within 7-9 days after infection. Therefore, diagnosis is complicated in endemically infected swine herds presenting no obvious clinical signs. This study aimed to investigate the right time point for sampling to detect swIAV. A cross-sectional study was performed in 131 farms from 12 European countries. The sampling protocol included suckling piglets, weaners, and nursery pigs. In each age group, 10 nasal swabs were collected and further examined in pools of 5 for swIAV by Matrix rRT-PCR, followed by a multiplex RT-PCR to determine the influenza subtype. SwIAV was detected in 284 (37.9%) of the samples and on 103 (78.6%) farms. Despite the highest number of animals with clinical signs being found in the nursery, the weaners were significantly more often virus-positive compared to nursery pigs ( = 0.048). Overall, the swIAV detection rate did not significantly differ between diseased or non-diseased suckling and nursery piglets, respectively; however, diseased weaners had significantly more positive pools than the non-diseased animals. Interestingly, in 9 farms, different subtypes were detected in different age groups. Our findings indicate that to detect all circulating swIAV subtypes on a farm, different age groups should be sampled. Additionally, the sampling strategy should also aim to include non-diseased animals, especially in the suckling period.
甲型猪流感病毒（swIAV）在猪呼吸道疾病综合征（PRDC）中起主要作用，感染后7 - 9天内会从呼吸道清除。因此，在没有明显临床症状的地方性感染猪群中进行诊断很复杂。本研究旨在调查检测swIAV的合适采样时间点。在来自12个欧洲国家的131个农场进行了一项横断面研究。采样方案包括哺乳仔猪、断奶仔猪和保育猪。在每个年龄组中，采集10份鼻拭子，并将其5份一组进行混合，通过基质逆转录-聚合酶链反应（Matrix rRT-PCR）检测swIAV，随后进行多重逆转录-聚合酶链反应以确定流感亚型。在284份（37.9%）样本和103个（78.6%）农场中检测到了swIAV。尽管在保育猪中发现有临床症状的动物数量最多，但与保育猪相比，断奶仔猪的病毒阳性率显著更高（P = 0.048）。总体而言，患病和未患病的哺乳仔猪及保育猪的swIAV检测率分别无显著差异；然而，患病断奶仔猪的阳性混合样本显著多于未患病动物。有趣的是，在9个农场中，不同年龄组检测到了不同的亚型。我们的研究结果表明，为了检测农场中所有流行的swIAV亚型，应采集不同年龄组的样本。此外，采样策略还应旨在纳入未患病动物，尤其是在哺乳阶段。
