Centre for Food-borne and Animal Parasitology, Canadian Food Inspection Agency, Saskatoon Laboratory, Saskatoon, Sask., Canada.
Vet Parasitol. 2010 Apr 19;169(1-2):93-101. doi: 10.1016/j.vetpar.2009.12.014. Epub 2009 Dec 22.
Cattle infected with the tapeworm cyst, Taenia saginata metacestode (synonym: Cysticercus bovis) are a source of human infection if affected beef is eaten raw or undercooked. Control measures targeted at individual cattle rather than all animals in a T. saginata-exposed herd should help reduce costs and alleviate current constraints associated with managing an outbreak. To that end, we have developed a reliable diagnostic test for use in live animals that would enable veterinary regulators to focus disease control strategies. The test detects bovine anti-T. saginata immunoglobulin G1 antibodies using an enzyme-linked immunosorbent assay (ELISA) which relies on the excretory-secretory antigens of T. saginata. Animals were inoculated with 10, 100 or 1000 viable T. saginata eggs in order to simulate the parasite burden of field-infected animals (parasite load=1-86; n=28). By testing sera obtained from the inoculated animals 84 days post-inoculation, test sensitivity was estimated to be 92.9% (95% confidence interval or CI=83.4-100.0%). Another 17 animals inoculated with 5000 or 10,000 viable eggs of T. saginata and shown to harbour metacestodes at post-mortem, all tested positive in the ELISA. Test specificity estimated from a herd of field animals with no historical, epidemiological, or post-mortem evidence of infection was 90.6% (95% CI=87.0-94.2%; n=256 field cattle). Using the test on samples (n=347) from a T. saginata-infected feedlot, the Bayesian approach estimate of seroprevalence was 4.6% (95% probability intervals=0.5-10.3%). The test performance characteristics of the ELISA suggest that it will be adequate for field application in bovine cysticercosis outbreaks.
牛感染带绦虫囊尾蚴（同义词：牛囊尾蚴），如果食用生的或未煮熟的受感染牛肉，会成为人类感染的来源。针对个别牛而不是暴露于带绦虫的牛群中的所有动物采取的控制措施应有助于降低成本并减轻管理疫情相关的当前限制。为此，我们开发了一种可靠的诊断测试方法，可用于活牛，使兽医监管机构能够专注于疾病控制策略。该测试使用酶联免疫吸附测定法（ELISA）检测牛抗带绦虫免疫球蛋白 G1 抗体，该方法依赖于带绦虫的排泄-分泌抗原。为了模拟现场感染动物的寄生虫负担（寄生虫负荷=1-86；n=28），将 10、100 或 1000 个有活力的带绦虫卵接种给动物。通过检测接种后 84 天获得的血清，估计测试的敏感性为 92.9%（95%置信区间或 CI=83.4-100.0%）。另外，在剖检中还发现 17 只动物接种了 5000 或 10,000 个有活力的带绦虫卵，并携带囊尾蚴，这些动物在 ELISA 中均呈阳性。从没有感染的历史、流行病学或剖检证据的牧场动物群中估计的测试特异性为 90.6%（95%CI=87.0-94.2%；n=256 头牧场牛）。在一个带绦虫感染的育肥场使用该测试对样本（n=347）进行检测，贝叶斯方法估计的血清阳性率为 4.6%（95%概率区间=0.5-10.3%）。ELISA 的测试性能特征表明，它将足以用于牛囊尾蚴病疫情的现场应用。
