Clinic for Swine, Department for Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, HongKong, China.
Transbound Emerg Dis. 2020 Nov;67(6):2770-2774. doi: 10.1111/tbed.13636. Epub 2020 Jun 2.
Atypical porcine pestivirus (APPV) has recently been reported to be associated with congenital tremor in newborn piglets. Only limited information is available about the prevalence at herd level in endemically infected herds. Therefore, the aim of this study was to determine the within-herd prevalence of APPV in a sub-clinically infected sow herd in Switzerland and to analyse associations between the serological status as well as the age and sex of the pigs, litter number and days after the last insemination. In a census sampling, blood was collected from 125 sows, aged 180 days or older, and six boars. Sera were examined applying an indirect APPV-specific ELISA to individual sera and an APPV RT-PCR targeting the NS3 encoding regions of APPV to pools of five. The APPV antibody status was classified into low (S/P value ≤ 0.5), intermediate (S/P value = 0.5-1) and high reactivity (S/P value > 1.0). None of the pooled serum samples was positive for specific genome fragments of APPV. Of the 131 samples, 53.4% were highly reactive, 39.7% showed an intermediate reactivity, and 6.9% showed a low reactivity in the indirect ELISA, that is, were serologically negative. Significant associations between the S/P values and the age of the pigs (p < .001), the litter number (p < .001) and the numbers of days after the last insemination (p = .0188) were observed. The results indicate that this sow herd was previously infected with APPV, while viremia was not detected in any of the adult pigs. This might explain the absence of clinical signs in the suckling pigs. Potential reinfection and circulation of APPV in this sow herd might be due to semen from commercial boar studs or APPV-positive animals in the absence of specific clinical signs.
最近有报道称，非典型猪瘟病毒（APPV）与新生仔猪先天性震颤有关。关于地方性感染畜群中畜群水平的流行率，只有有限的信息。因此，本研究旨在确定瑞士一个亚临床感染母猪群中 APPV 的群内流行率，并分析血清学状态以及猪的年龄和性别、窝产仔数和上次配种后天数之间的关联。采用普查抽样法，采集了 125 头 180 天或以上龄的母猪和 6 头公猪的血液。将血清应用 APPV 特异性间接 ELISA 对个体血清进行检测，并用 APPV RT-PCR 对 APPV 的 NS3 编码区进行检测，以 5 个血清为一组进行检测。将 APPV 抗体状态分为低（S/P 值≤0.5）、中（S/P 值=0.5-1）和高反应性（S/P 值>1.0）。没有一组混合血清样品对 APPV 的特定基因组片段呈阳性。在 131 个样本中，53.4%呈高反应性，39.7%呈中间反应性，6.9%呈低反应性，间接 ELISA 检测呈血清阴性。S/P 值与猪的年龄（p<0.001）、窝产仔数（p<0.001）和上次配种后天数（p=0.0188）之间存在显著关联。结果表明，该母猪群曾感染过 APPV，但成年猪未检测到病毒血症。这可能解释了哺乳仔猪没有临床症状的原因。该母猪群中 APPV 的潜在再感染和循环可能是由于来自商业公猪精液库或 APPV 阳性动物的精液，而没有特定的临床症状。
