| Summary: | [中文文摘]目的回顾棘球绦虫及其棘球蚴病的当代研究成果,着重论述我国对本虫病原学和流行学的研究贡献。方法评阅有关本虫病的研究资料,分析、讨论、总结本病原虫种、终期和中间宿主动物,病原与宿主之间相互关系及其流行、传播规律。结论当代全球有7种棘球绦虫,我国有5种,其中石渠棘球绦虫是青藏高原特有的新虫种。全球有20多种食肉兽类作为终期宿主,我国已知自然感染有5种,其中藏狐为宿主新记录。细粒棘球绦虫的中间宿主除大型家畜(牛、马、羊、猪)外,尚有多种鹿类有蹄动物和人体等。多房性棘球绦虫的中间宿主有9科26属46种啮齿类动物,我国已报道有6科10属14种啮齿动物为自然宿主,人体也会感染。此外绵羊、牦牛、猪等家畜虽报道有自然感染多房蚴,但病理学显示病肝组织纤维化,泡囊均无原头节,与人体感染的肝病变相似,拟是不正常的中间宿主或是多囊性的细粒棘球蚴感染。[英文文摘]There are seven Echinococcus pathogens of hydatid disease reported from the world,and five species are found in China.Among them,E.shiquicus,collected from eastern Tibetan plateau in Sichuan Province of China,is described as a new species by Xiao et al(2005).Its adult worm is the smallest one in Echinococcus spp.The majority of them contain a single immature proglottid and a single gravid proglottid,lacking mature proglottid.The Tibetan fox,Vulpes ferrilata,is confirmed as the final host of E.shiquicus,and the plateau pika,Ochotona curzoniae,serves as the intermediate host.In the host liver,the metacestode develops into unilocular hydatid cyst,with no daughter cyst.Domestic dog and human are not found to be infected with either adult or metacestode so far.E.granulosus is recognized with two forms on the basis of differences in host-specify.The Northern Form of E.granulosus distributes in the holarctic zone of tundra and boreal forest or Taiga.Its natural cycle is perpetuated by the predator-prey relationship existing between wolf and large deer.The Domestic Form(European Form) of E.granulosus reveals nearly cosmopolitan distribution,and its life cycle involves both domestic dog and ungulates as final and intermediate host respectively.The latter form appears to be the most important pathogen of hydatid disease in the world.In China,the unilocular dydatid disease pathogen belongs to the Domestic Form,but there probably exist complex infection with the Northern Form in some pasture lands at Northwest China.E.multilocularis or multilocular(alveolar) hydatid cyst is recognized as an important pathogen of zoonoses in the world.This cestode-pathogen distributes throughout the holarctic zone of tundra,involving Europe,Siberia,Northern Japan,subarctic islands and North America.The typical life cycle involves foxes and rodents.According to the published data from local hospitals or institutes of parasitic disease in China,during 1965-2008,more than 1 000 human AHD(alveolar hydatid disease)cases have been reported in 12 provinces or autonomous regions,including 70-odd districts or cities.About 11 species of carnivorous animals are recorded as natural final hosts in the world,including 5 species from China.Especially,the Tibetan fox,Vulpes ferrilata,is confirmed to be a new final host record from the world.At least 9 families,26 genera and 46 species of rodents are recorded as intermediate hosts from the world(Rausch,1986;Vuitton et al.,2003).In China,8 families,13 genera and 17 species of mammals are reported as natural intermediate hosts,in which yak 8.6%(66/766),sheep 7.5%(3/40) and pig 3.1%(1/32) are infected with AHD in Shiqu County,the plateau region of western Sichuan Province(Qiu et al,1995).In addition,the viewpoint that large domestic ungulate animals can be infected with alveolar hydatid disease is criticized by some authoritative parasitologists,who regard it to be confused with polycystic infection of E.granulosus(Rausch,1967,1986).The evidences for such problem require further observations or animal examinations in the future. After Vogel(1957) suggested E.sibiricensis as a geographic subspecies of high-latitude form,three subspecies,such as ①E.m.multilocularis Leuckard,②E.m.sibiricensis Rausch et schiller and ③E.m.kazakhensis Shul’ts,are recognized by Rausch(1967,1968),but the problem of multilo-echinococcid subspecificity remains in abeyance up to now.Following a series of studies on the etiology,epidemiology and developmental life cycle examinations,Tang et al(1988-2007) discriminate that the three subspecies of E.multilocularis from Inner Mongolia appear to have their distinct characteristics of uterus in gravid proglottid and of metacestode development in rodent host.Based on the excellent research achievements,they demonstrate that the three subspecies are valid species respectively.Namely,both E.m.multilocularis and E.m.sibiricensis need to recover their original scientific names: E.multilocularis and E.sibiricensis.Besides,a new species of Echinococcus,in stead of the Russian form E.m.kazakhensis,is described,which has a spherical uterus in the gravid proglottid.Its metacestode obtained from naturally and artificially infected rodents develops like polycystic hydatid cyst,with large alveolar vesicles and brood capsules,and the protoscolexes are produced from both germinal layer and reticular meshes in the alveolar cysts.Nevertheless,the metacestode in experimentally infected lambs cannot develop.In memory of the late Russian parasitologist,who first discovered this type of morphologic characteristics of Echinococcus adult worm from Kazakhstan,Tang et al(2007)designate it E.russicensis sp.nov.
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