Baumgartner M, Brugnera E, Sydler T, Bürgi E, Hässig M, Sidler X
Department for Farm Animals, University of Zurich, Switzerland.
Schweiz Arch Tierheilkd. 2012 Oct;154(10):429-36. doi: 10.1024/0036-7281/a000379.
Postweaning multisystemic wasting syndrome (PMWS) was epizoozic between 2003 and 2008 in Switzerland. Nevertheless, infectious risk factors including porcine reproductive and respiratory syndrome virus (PRRSV) were missing at all or were seen only sporadically (enzootic pneumonia and actinobazillosis). In a case-control study, 30 farms with PMWS affected pigs were compared to 30 inconspicious farms ("matched pairs"). The case-control allocation was verified by PCV2 DNA measurements of 5 healthy weaned pigs in each control farm, 5 healthy and 5 PMWS affected weaners in each PMWS affected farm. Diseased pigs showed in average 1.8x10(8) DNA templates per ml serum significantly higher than healthy pigs from control farms with 1x10(6) DNA templates per ml serum. Virus load in healthy pigs did not differ between control- and PMWS affected farms. PMWS mainly emerged among affected pigs in the 5th to 8th week of age. In a logistic regression model risk factors were identified such as high occupancy in weaning pens (p = 0.002), large groups in gestation facilities (p = 0.03) as well as reduced birth weight < 1.3 kg (p = 0.04). We suggest these factors might have lead to chronic stress e.g. through influencing negatively social interaction in pigs or disturbances of the maturing immune system. Heavy fly and rodent infestation might not only be viewed as a vector for disease transmission, but, also as a stress factor.
断奶后多系统消耗综合征（PMWS）在2003年至2008年期间在瑞士呈流行性发生。然而，包括猪繁殖与呼吸综合征病毒（PRRSV）在内的感染性风险因素要么完全不存在，要么仅偶尔出现（地方流行性肺炎和放线菌病）。在一项病例对照研究中，将30个有PMWS感染猪的农场与30个无明显症状的农场（“配对组”）进行了比较。通过对每个对照农场的5头健康断奶仔猪、每个受PMWS影响农场的5头健康断奶仔猪和5头受PMWS影响的断奶仔猪进行PCV2 DNA检测，验证了病例对照的分配情况。患病猪每毫升血清平均有1.8×10⁸个DNA模板，显著高于对照农场每毫升血清有1×10⁶个DNA模板的健康猪。对照农场和受PMWS影响农场的健康猪的病毒载量没有差异。PMWS主要出现在受影响猪5至8周龄时。在逻辑回归模型中确定了风险因素，如断奶仔猪栏位占有率高（p = 0.002）、妊娠设施中大群体饲养（p = 0.03）以及出生体重降低<1.3千克（p = 0.04）。我们认为这些因素可能导致慢性应激，例如通过对猪的社交互动产生负面影响或干扰免疫系统成熟。严重的苍蝇和啮齿动物侵扰不仅可能被视为疾病传播的媒介，而且也是一种应激因素。
