Stadler Julia, Moser Lisa, Numberger Jasmin, Rieger Anna, Strutzberg-Minder Katrin, Stellberger Thorsten, Ladinig Andrea, Ritzmann Mathias, Fux Robert
Clinic for Swine, Centre for Clinical Veterinary Medicine, LMU Munich, Sonnenstrasse 16, 85764, Oberschleissheim, Germany.
IVD Innovative Veterinary Diagnostics Laboratory, Albert-Einstein-Strasse 5, 30926, Seelze, Germany.
Prev Vet Med. 2018 Feb 1;150:93-100. doi: 10.1016/j.prevetmed.2017.12.012. Epub 2017 Dec 19.
Porcine epidemic diarrhea (PED) has reemerged in Europe since 2014. Characterized by a rapid onset of diarrhea in pigs of all ages, morbidity can reach up to 100% whereas mortality is variable. The virus strains involved in the recent European outbreaks all cluster together with US strains (S INDEL) that lead to less severe clinical signs. In this study, fattening pigs and suckling piglets (n = 105) on farms with no prior PED history were monitored after an acute outbreak of the disease, caused by an S INDEL strain of PED virus (PEDV). For diagnostic investigations in the affected farms, real time RT-PCR was performed to detect PEDV RNA in individually taken fecal samples, and two commercial ELISA kits, both based on the N protein of PEDV, were used to detect IgG in serum samples of pigs experiencing acute signs of the disease. PEDV RNA could be detected in fecal samples up to 14 days after initial sampling. Comparing both ELISAs by Cohens Kappa showed substantial agreement (κ = 0,771). Antibodies were detectable in all fattening pigs (100%) within 10 days after the occurrence of first clinical signs and remained detectable for about two months at least in 20.6% (farm 1) and 45.7% (farm 2) of the animals, respectively. In contrast, only 18 of 34 (52.9%) suckling piglets seroconverted. Although, PEDV RNA was found in fecal samples of all piglets, 13 piglets did not demonstrate antibodies at any sampling day. PCR to detect PEDV RNA in fecal samples seems to be a reliable diagnostic tool during and after the acute outbreak. In the present study, IgG ELISA kits proved to be a feasible diagnostic tool, but age dependent differences in detection rate and persistence of antibodies need to be considered.
自2014年以来，猪流行性腹泻（PED）在欧洲再度出现。其特征是所有年龄段的猪都迅速出现腹泻，发病率可达100%，而死亡率则各不相同。近期欧洲疫情中涉及的病毒株均与美国毒株（S INDEL）聚集在一起，这些毒株导致的临床症状较轻。在本研究中，对之前无PED病史的农场中的育肥猪和哺乳仔猪（n = 105）在由PED病毒（PEDV）的S INDEL毒株引起的急性疾病爆发后进行了监测。为了在受影响的农场进行诊断调查，采用实时RT-PCR检测单独采集的粪便样本中的PEDV RNA，并使用两种均基于PEDV N蛋白的商业ELISA试剂盒检测出现急性疾病症状的猪血清样本中的IgG。在初次采样后长达14天的粪便样本中均可检测到PEDV RNA。通过科恩斯kappa系数比较两种ELISA方法显示出高度一致性（κ = 0.771）。在首次出现临床症状后的10天内，所有育肥猪（100%）均可检测到抗体，并且至少在20.6%（农场1）和45.7%（农场2）的动物中可检测到抗体约两个月。相比之下，34头哺乳仔猪中只有18头（52.9%）发生了血清转化。尽管在所有仔猪的粪便样本中都发现了PEDV RNA，但13头仔猪在任何采样日都未显示出抗体。在急性疫情期间及之后，检测粪便样本中PEDV RNA的PCR似乎是一种可靠的诊断工具。在本研究中，IgG ELISA试剂盒被证明是一种可行的诊断工具，但需要考虑抗体检测率和持久性的年龄依赖性差异。
