Echinococcus multilocularis

PURPOSE OF REVIEW: Echinococcus multilocularis is a tapeworm of foxes that may cause a zoonotic infection resulting in a highly pathogenic and potentially fatal chronic liver infestation called human alveolar echinococcosis. Radical liver resection currently offers the only potential cure. Although alveolar echinococcosis is a rare parasitic disease that is restricted to transmission in the northern hemisphere, the parasite is geographically widespread being distributed from Alaska, across Canada and north central USA, through northern Europe and Eurasia to Japan. The present review summarizes the background to this helminthic infection and recent contributions in areas of pathology, diagnosis, treatment and transmission. RECENT FINDINGS: Concern is growing in Europe that the prevalence and distribution of E. multilocularis in red foxes has increased significantly in the last 10-15 years. A retrospective analysis revealed >550 cases of human alveolar echinococcosis diagnosed between 1982-2000, with the majority in France, Germany and Switzerland. Human prevalence rates >3% occur in central northwest China and the disease is of public health concern in northern Japan. Improvements in immunodiagnosis with native and recombinant antigens have enabled more accurate confirmation of hepatic image findings, while development of in-vitro culture of metacestode tissues provides a useful model for screening new anti-alveolar echinococcosis drugs as alternatives to albendazole and surgery. Recombinant molecules from the oncosphere and metacestode stages have shown potential as vaccine candidates. New tools of coproantigen and copro-DNA detection for vulpine infections have proved highly beneficial in epidemiological and transmission ecology studies, as has a landscape ecology approach to develop risk models for communities in endemic areas. SUMMARY: It is possible that human AE will become an emergent zoonosis in some regions of Europe and Eurasia. Improvements in diagnostic and treatment approaches are being investigated. Further understanding of host immune responses will aid in characterization of disease pathology. Control of E. multilocularis in its natural cycles will be difficult due to the involvement of wild animal hosts, however use of anthelminthic baits and dosing of domestic dogs may reduce transmission at local scales.     

Echinococcosis multilocularis in Turkey

We present 20 new cases of Echinococcosis multilocularis (EM) and have also reviewed all 137 previously reported cases from Turkey. The total number of cases is now 157 up until the end of 1983. Of 146 cases with information on their place of occurrence, 133 (91%) were from eastern and central parts of Turkey or the region of the Black Sea where the cold climate is predominant. This area should be considered as part of the geographic distribution of Echinococcus multilocularis which extends from the Caucasian Republics (Azerbaijan and Georgian S.S.R.) to Siberia in the Soviet Union. EM is more frequent among the people involved in raising livestock in the rural areas of Turkey. Most of the cases (76%) were between the ages of 30 and 50; 53% were males. One hundred and thirty nine cases (92%) were liver infections, and most of the cases (60%) were clinically diagnosed as liver tumour.     

多房棘球绦虫信号转导体系

信号通路是细胞接收各种刺激信号的途径,从而做出相应反应,如细胞增殖、分化及凋亡等。在多房棘球绦虫(Echinococcus multilocularis)感染宿主后,自身细胞及宿主细胞可分泌多种细胞因子,通过细胞表面的受体,将刺激信号传递到细胞内,引起棘球绦虫或宿主细胞相应变化,使棘球绦虫能够在宿主体内生长繁殖。通过对信号通路的研究,研制阻断信号通路的药物,对控制泡型棘球蚴病具有重要的意义。     

新疆北部多房棘球绦虫动物宿主研究初报

本文报告在新疆北部泡型包虫病流行地区的农村牧区以及山地和草原地带进行多房棘球绦虫终宿主和中间宿主调查的结果。采用槟榔碱导泻法检查 30 5只家 (牧 )犬 ,在 5 2只犬中检出棘球绦虫成虫 ,感染率为 17%。对所获 13974条虫体进行鉴定的结果 ,皆为细粒棘球绦虫。表明在新疆北部泡型包虫病流行地区 ,家犬不是多房棘球绦虫的终宿主。检查啮齿目动物 31种 5 16 3只 ,食虫目动物 4种 2 6 1只和兔形目动物 2种 196只。在西部天山地区捕获的伊犁田鼠和塔尔巴哈台山地区捕获的水鼠平中发现多房棘球蚴感染 ,表明这两种鼠类是当地多房棘球绦虫的中间宿主。属于国内新记录。     

X线照射泡球蚴原头节的体外实验研究

目的探讨X线对体外培养的泡球蚴原头节的杀伤作用。方法无菌采集子午沙鼠体内的泡球蚴中含原头节的囊液,将其加入RPMI 1640培养液中培养。原头节体外培养3 d后分装至培养瓶中,每组10瓶,每瓶约含10 000个原头节,设空白对照组、低剂量组(15 Gy和30 Gy)、中剂量组(45 Gy和60 Gy)、高剂量组(75 Gy和90 Gy)、阿苯达唑组(2 500 ng/ml)、45 Gy X线+2 500 ng/ml阿苯达唑组和75 Gy X线+2 500 ng/ml阿苯达唑组。X线照射剂量率为200 cGy/min,源皮距为100 cm。体外培养第4天开始照射,每组共照射3次,每次间隔1 d。首次照射后第1天开始每天取原头节培养液,0.1%伊红染色,光镜下计数每100个原头节中着色原头节数目,每组计算300个原头节的平均死亡率,直至实验组原头节全部死亡为止。同时光镜下观察经X线照射后原头节的变化。结果不同放射剂量组的原头节死亡率与空白对照组间的差异均有统计学意义(P<0.05)。阿苯达唑组原头节死亡率与放射线联合阿苯达唑组间的差异均有统计学意义(P<0.05),且显著高于空白对照组(P<0.05)。其中,X线...     

甘肃省合作牦牛自然感染多房棘球蚴的调查

本文报告甘肃合作牦牛自然感染多房棘球蚴，感染率１．６％。病理学观察，多房棘球蚴发育不良，无生发层与原头节存在，与人体多房棘球蚴病理观察相似。     

Inferior Vena Cava Syndrome Due to Echinococcus multilocularis

Alveolar echinococcosis is an invasive, tumor-like zoonosis, accidentally transmitted to humans. We present a case of recurrent inferior vena cava (IVC) syndrome due to alveolar echinococcosis and strongly suspected on transthoracic echocardiographic examination.     

多房棘球绦虫基因研究进展

多房棘球绦虫 (Echinococcus multilocularis,Em)属绦虫纲 (Class cestode) ,其成虫寄生于狐等终宿主小肠内 ,呈扁平多带状小型寄生虫 ,幼虫寄生于以野生啮齿动物为主的中间宿主 ,如野鼠等的肝、肺等器官中。流行区家养的食肉动物如猫、狗等可因捕食中间宿主或喂食被 Em幼虫感染的动物内脏而感染成为终宿主 ,排泻虫卵 ,造成与之接触的人的感染 [1 ]。继绦期幼虫寄生于人体内 (多见于肝 )浸润迁移生长 ,类似癌症 ,危害极大 ,被视为最致命的蠕虫感染之一。 Em幼虫寄生所致的疾病称为多房包虫病或多房型棘球幼病(Alveolaris Echinococcosis,…     

Echinococcus multilocularis infection in pet dogs in Japan

A survey of Echinococcus multilocularis infections in pet dogs in Japan from 1997 to 2007 was conducted by testing for coproantigen reactivity, fecal taeniid eggs, and egg DNA. In Hokkaido, the only island where E. multilocularis is endemic in Japan, 18 of 4768 dogs (0.4%) excreted taeniid eggs that were positive for E. multilocularis DNA by polymerase chain reaction (PCR). Most of the dogs testing positive for egg DNA were kept free-range, but three dogs had been kept inside their owners' houses. In addition, 15 dogs were suspected to be infected based on the results of a coproantigen test. One dog, which was transported from Hokkaido to Honshu, the main island of Japan, was excreting taeniid eggs that were positive for E. multilocularis DNA by PCR. These results suggest the importance of proper pet management in disease prevention, even for dogs kept indoors, and they point out a possible means by which the parasite may be introduced into non-endemic areas through transport of infected dogs.     

Experimental imaginal Echinococcus multilocularis infestation of golden hamsters

The imago stage of Echinococcus multilocularis development (prior to maturation of parasite oocysts) has been described in the intestine of golden hamsters infected by parenteral penetration of an Alveococcus agent and given hydrocortisone subcutaneously for 3 days before the infection and on the day of the infection, mean total drug dose being about 250 mg/kg. The number of helminths developed on days 8-35 of postinvasion ranged from 432 to 1863, their length was 1.0 to 4.0 mm and the number of segments did not exceed 2. Oocyst maturation was noted on day 20 of postinvasion. High oocyst invasiveness was confirmed by a biological test on 32 cotton rats aged 1-1.5 months who were administered parenterally 2-3 helminths containing 86 to 284 oocysts. All the rats died of severe hepatic alveococcosis on days 24-43 of postinfection.     

Monoclonal antibodies specific to carbohydrates of Echinococcus multilocularis

To investigate the complexity of epitopes presented on Echinococcus multilocularis (E.m.) metacestode carbohydrates, a panel of monoclonal antibodies (MoAbs) was generated and characterized. Thirty of the clones were obtained and classified into three types (types I to III) based on Western blotting (WB) and dot-ELISA. One MoAb (type I) appeared to react with one of the carbohydrate antigens (C-antigens) located at 30-35 kDa, and was the most effective diagnostic antigen for human alveolar hydatid disease (AHD) in Hokkaido, Japan. The second group (15 clones) of MoAb (type II) reacted with another C-antigen; one which also induced antibody response in AHD patients. The third group (14 clones) of MoAb (type III) reacted with other C-antigens both in ELISA and dot-ELISA, but did not react in WB. Cross-reaction to the antigens of Echinococcus granulosus was faintly observed in only the type I-MoAb by dot-ELISA. In the immunohistological studies, all of the MoAbs reacted strongly with the laminated layer though not with protoscoleces in metacestode tissue prepared from experimentally infected cotton rats. Tissue sections treated with sodium periodate lost their immunoreactivity, suggesting that these MoAbs recognized carbohydrate epitopes of the E.m. metacestode.     

新疆塔城地区和布克塞尔县赤颊黄鼠腹腔接种多房棘球蚴的实验观察

中英法三国包虫病研究项目小组在欧共体ＥＥＣ－ＳＴＤ３项目，中法科学技术友好促进会支持下，于１９９６年在新疆和布克塞布县进行了包虫病流行病学及生态学研究，将现场捕捉野鼠一赤颊黄鼠带回新疆医学院作多房棘球蚴感染敏感性实验，感染率功率达８０％，说明赤颊黄鼠对多房棘球蚴高度敏感。有可能在塔城，阿勒泰地区的多房棘球蚴病流行中起重要作用。