Deplazes P, Eckert J
Institute of Parasitology, University of Zürich, Switzerland.
Appl Parasitol. 1996 Dec;37(4):245-52.
In view of the considerable public health significance of Echinococcus multilocularis, the causative agent of the highly lethal human alveolar echinococcosis, there is an urgent need for reliable and simple techniques for the diagnosis of the infection in populations of final hosts (foxes, dogs, cats) and also in individual dogs and cats. The standard technique presently used is parsitological examination of the small intestine at necropsy. This reliable technique requires high expenditure and special safety precautions. An alternative approach is coproantigen detection. Recently, in our laboratory an ELISA was evaluated using rabbit and chicken polyclonal antibodies against E. multilocularis antigens (affinity purified coproantigens and somatic adult worm antigens). The specificity of this test (evaluated in 20 foxes and 661 dogs with helmintic infections other than E. multilocularis) was very high (95%-99.5%). Average sensitivity in 35 foxes infected with E. multilocularis was 80%, but reached 93% in foxes with individual worm burdens over 55. A Polymerase Chain Reaction (PCR) was used for detecting DNA of E. multilocular is in faecal samples of foxes after the parasite eggs had been isolated by a sieving procedure. In a total of 55 foxes specificity was 100% and sensitivity 94%. For field application the coproantigen ELISA has the potential of replacing parasite detection at necropsy, and PCR is a valuable method for confirmation of positive coproantigen results and for diagnosis in individual animals. Detection of circulating anti-Em2 antibodies by ELISA may be useful for primary screening of fox populations but antibody prevalence rates do not correlate with prevalence rates of the intestinal infection with E. multilocularis.
鉴于多房棘球绦虫是高致死性人体肺泡型棘球蚴病的病原体，对公众健康具有重大意义，因此迫切需要可靠且简便的技术来诊断终末宿主（狐狸、狗、猫）群体以及个体猫狗中的感染情况。目前使用的标准技术是在尸检时对小肠进行寄生虫学检查。这种可靠的技术需要高昂的费用和特殊的安全防范措施。另一种方法是检测粪抗原。最近，我们实验室评估了一种酶联免疫吸附测定（ELISA），该方法使用了针对多房棘球绦虫抗原（亲和纯化的粪抗原和成虫体抗原）的兔和鸡多克隆抗体。该检测方法的特异性（在20只狐狸和661只感染了除多房棘球绦虫以外的蠕虫的狗中进行评估）非常高（95%-99.5%）。在35只感染多房棘球绦虫的狐狸中，平均灵敏度为80%，但在虫负荷超过55的狐狸中灵敏度达到了93%。通过筛分程序分离寄生虫卵后，使用聚合酶链反应（PCR）检测狐狸粪便样本中的多房棘球绦虫DNA。在总共55只狐狸中，特异性为100%，灵敏度为94%。对于现场应用，粪抗原ELISA有潜力取代尸检时的寄生虫检测，而PCR是确认粪抗原阳性结果和诊断个体动物的有价值方法。通过ELISA检测循环抗Em2抗体可能有助于对狐狸群体进行初步筛查，但抗体流行率与多房棘球绦虫肠道感染的流行率不相关。
