Department of Animal Pathology, Faculty of Veterinary Medicine, University of Turin, da Vinci 44, Grugliasco (TO), Italy.
Foodborne Pathog Dis. 2010 Oct;7(10):1171-5. doi: 10.1089/fpd.2009.0530.
Bovine cysticercosis is caused by the larval stage of the human tapeworm Taenia saginata. According to European data on meat inspection, the prevalence ranges from 0.007% to 6.8%, but the real prevalence is considered to be at least 10 times higher. Laboratory confirmation of the etiological agent is based on gross, stereomicroscopic, and histological examination of submitted specimens. False identifications may occur, possibly because of death and degeneration of cysts, or because taeniid larvae and other tissue parasites, such as Sarcocystis spp., may cause similar macroscopic morphological lesions. Therefore, tests that can warrant sure identification of taeniid lesions and calcified cysts in the muscle are needed. The focus of our study was to develop a suitable postmortem test that could be applied on putative lesions by T. saginata cysticerci, as ambiguously diagnosed after routine meat inspection. In particular, we proposed a biomolecular assay targeting the mitochondrial cytochrome c oxidase subunit I gene (COI). For developing the polymerase chain reaction assay, viable cysts of Cysticercus bovis (n = 10) were used as positive reference samples, and those of Echinococcus granulosus (n = 3), Cysticercus tenuicollis (n = 3), and Sarcocystis spp. (n = 4) as reference negative controls. Further, to evaluate the applicability of the proposed assay, 171 samples of bovine muscular tissue, obtained from local slaughterhouses and containing lesions recognized as T. saginata cysticerci by macroscopic examination, were tested. The proposed test confirmed the diagnosis at postmortem inspection in 94.7% (162/171) of samples. In conclusion, the assay developed in this study, amplifying a short fragment from the mitochondrial gene COI, showed to be suitable for samples containing both viable and degenerating T. saginata cysticerci, yielding an unequivocal diagnosis.
牛囊尾蚴病是由人体带绦虫（牛带绦虫）的幼虫阶段引起的。根据欧洲肉类检查数据，该病的流行率范围为 0.007%至 6.8%，但实际流行率被认为至少高出 10 倍。病原的实验室确认基于提交样本的大体、立体显微镜和组织学检查。可能会发生错误鉴定，这可能是由于囊肿的死亡和退化，或者是由于带绦虫幼虫和其他组织寄生虫，如 Sarcocystis spp.，可能导致类似的宏观形态病变。因此，需要进行可以保证在肌肉中鉴定带绦虫病变和钙化囊肿的测试。我们的研究重点是开发一种合适的死后测试，该测试可应用于 T. saginata 囊尾蚴在常规肉类检查后被含糊诊断的疑似病变。特别是，我们提出了一种针对线粒体细胞色素 c 氧化酶亚基 I 基因（COI）的生物分子检测方法。为了开发聚合酶链反应检测方法，我们使用了牛带绦虫囊尾蚴（n=10）的活囊作为阳性参考样本，以及细粒棘球绦虫囊尾蚴（n=3）、细劲囊尾蚴（n=3）和 Sarcocystis spp.囊尾蚴（n=4）作为阴性参考对照。此外，为了评估拟议检测方法的适用性，我们对从当地屠宰场获得的 171 份含有被宏观检查认定为 T. saginata 囊尾蚴的肌肉组织样本进行了测试。在 171 份样本中，拟议的检测方法在死后检查中确认了 94.7%（162/171）的诊断。总之，该研究中开发的检测方法，扩增了来自线粒体基因 COI 的短片段，显示出适合于含有活的和退化的 T. saginata 囊尾蚴的样本，得出了明确的诊断。
