东南欧国家旋毛虫病的流行现状

旋毛虫病在东南欧的巴尔干半岛及临近国家的流行现状各不相同,在保加利亚、塞尔维亚和黑山、罗马尼亚及克罗地亚,猪和人的旋毛虫感染率均较高;在波斯尼亚和黑塞哥维那则具有中度的旋毛虫感染率;在匈牙利已有多年未发现人体旋毛虫病,但近2年来已发现了散发的猪旋毛虫病。旋毛虫病在东南欧国家的再度肆虐,提示旋毛虫病能够突破食品安全体系和兽医检疫的薄弱环节,从而可导致地区性、全国性甚至国际性的旋毛虫病扩散。该文对旋毛虫病在东南欧国家的历史、分布、流行现状、感染来源、虫种及再度肆虐的原因等进行了综述。     

旋毛虫、卫氏并殖吸虫及华支睾吸虫之间共同抗原的研究

目的鉴定旋毛虫、卫氏并殖吸虫及华支睾吸虫之间的共同抗原,避免血清学诊断这3种寄生虫病时的交叉反应。方法应用十二烷基硫酸钠-聚丙烯酸胺凝胶电泳(SDS-PAGE)和免疫印渍(Western blot)对旋毛虫肌幼虫、卫氏并殖吸虫成虫及华支睾吸虫成虫可溶性抗原中的蛋白组分进行研究。结果旋毛虫肌幼虫、卫氏并殖吸虫成虫及华文睾吸虫成虫3者相同蛋白带的分子量为108、65、53、43、42、31、25、16 kDa。免疫印渍结果表明,旋毛虫和卫氏并殖吸虫抗原中分子量为 65、58、53kDa的蛋白带均与旋毛虫感染的大鼠、小鼠及患者血清、肺吸虫感染的大鼠和患者血清发生反应;旋毛虫和华支睾吸虫抗原中分子量为108kDa的蛋白带均与旋毛虫感染的大鼠、小鼠及患者血清、肝吸虫病患者血清发生反应;而3种可溶性抗原中的53kDa与本实验中所有寄生虫感染的动物和患者均有交叉反应。结论 65、58、53 kDa蛋白为旋毛虫和卫氏并殖吸虫的共同抗原,108kDa蛋白为旋毛虫和华支睾吸虫的共同抗原,而53 kDa蛋白为这3种寄生虫的共同抗原。     

一起食源性群体旋毛虫感染调查报告

2004年2月，云南大理市发生一起食源性群体旋毛虫感染，累计发病132人，发病者年龄2．5～75岁。调查结果显示，患者均有集体食用生猪肉史，用餐12d后陆续发病。经病原治疗和对症治疗后病人均痊愈。     

The surfaces of the parasitic nematodes Trichinella spiralis and Toxocara canis differ in the binding of post-C3 components of human complement by the alternative pathway

The binding of human complement components C3, C5 and C9 to the surface of the infective larvae of the nematode parasites Toxocara canis and Trichinella spiralis, by the alternative pathway, was examined by direct and indirect immunofluorescence on the intact parasites. This showed that although C3 bound to both nematodes, they differed markedly in the binding of C5 and C9; C5 bound only minimally to T. spiralis, and C9 binding to this parasite was barely detectable. In contrast, both early and late components bound to T. canis to a high density, comparable to, or in excess of, the binding of these components to the infective larvae of the trematode Schistosoma mansoni. The lack of binding of the post-C3 components to T. spiralis did not correlate with enhanced binding of the control protein, Factor H.     

旋毛虫幼虫分泌物抗原在小鼠体内诱生肿瘤细胞毒因子的研究

本文应用Ｌ９２９细胞杀伤法，对注射旋毛虫肌肉期幼虫分泌物（Ｌ１ＥＳ）的小鼠血清进行了检测，发现Ｌ１ＥＳ对已注射卡介苗（ＢＣＧ）或感染旋毛虫的小鼠，均能诱生肿瘤细胞毒因子（ＴＣＦ），而正常对照鼠则不能发生，表明Ｌ１ＥＳ诱生ＴＣＦ需要首先激活巨噬细胞（Ｍφ）这一基本条件。将Ｌ１ＥＳ置３７℃、１ｈ，５６℃、３０ｍｉｎ或１００℃、２ｍｉｎ处理后，其诱生ＴＣＦ的能力均明显高于对照组（Ｐ＜０．０５）。Ｌ１ＥＳ     

旋毛虫表皮胶原蛋白基因的原核表达

目的构建表皮胶原蛋白基因X21的原核表达载体pET28-X21ex,诱导其表达胶原蛋白。方法应用PCR技术扩增目的基因X21,纯化后将其克隆入表达载体pET28a,重组质粒经酶切鉴定后,转入大肠杆菌DE3诱导表达,利用SDS-PAGE检测胶原蛋白的表达效果。结果利用DNA重组技术构建了表皮胶原蛋白基因X21的原核表达载体pET28-X21ex,转化大肠杆菌后经诱导表达了30kDa的融合蛋白,以诱导3h的表达量最高,在35%以上。结论旋毛虫表皮胶原蛋白基因X21在大肠杆菌中能够高效表达,为进一步研究旋毛虫表皮胶原蛋白的结构与功能奠定了基础。     

An outbreak of trichinellosis in farmed wild boar in Finland

Nine farmed wild boar out of 25 slaughtered from a single farm were condemned at meat inspection because of trichinellosis. With RAPD-PCR, Trichinella spiralis was identified in all positive wild boar. Out of the available serum samples (n=7), all wild boar which had failed the meat inspection showed seroconversion in ELISA and Western blotting, as did one additional animal which had passed the inspection. The animals became infected during an invasion of rats from an improperly closed dump near the farm. Unfortunately, by the time trichinellosis was discovered in the wild boar, the invasion had already been brought under control; thus, no samples from rats were available. However, having lived through the rat invasion was shown to be a risk factor for trichinellosis in wild boar (relative risk, RR=6.3). In wildlife samples from surrounding areas, sylvatic trichinellosis was found to be very common (74%; n= 19 red foxes). Intriguingly, the prevalent species in trichinella-positive foxes differed from that in wild boar, Trichinella nativa and T. spiralis being found in 12 foxes and in one fox, respectively.     

旋毛虫Ts87重组蛋白诱导的小鼠黏膜免疫保护性研究

本实验探讨旋毛虫Ts87重组蛋白灌胃免疫小鼠诱导的黏膜免疫保护性作用。实验分对照组、佐剂组(霍乱毒素B亚单位组,CTB)和免疫组(CTB Ts87重组蛋白),灌胃免疫,间隔1周共免疫3次。末次免疫后第7天用400条旋毛虫感染期幼虫攻击,比较3组小鼠肠道成虫数、雌虫生殖力和肌幼虫数。且于末次免疫后第7天刮取肠黏液、取血检测特异性sIgA、IgG抗体水平。结果显示免疫组小鼠成虫减虫率、新生蚴减虫率、肌幼虫减虫率分别是81·34%、67·02%、84·49%;小鼠肠黏液sIgA水平及血清IgG水平显著高于对照组和佐剂组。结果表明Ts87重组蛋白黏膜免疫能够诱导小鼠产生抗旋毛虫的保护性免疫。灌胃免疫能显著提高肠黏液特异性sIgA水平,对促进肠道成虫的排出有明显作用。     

Concurrent infections ofTrichinella spiralis andToxoplasma gondii in mice

Concurrent infections with two parasites: a nematode,Trichinella spiralis, and a protozoon,Toxoplasma gondii, were investigated. Antibody production (total immunoglobulin and IgM) was similar in double and single infections. However, the number ofToxoplasma cysts in the brains of mice infected withTrichinella and challenged 1–6 weeks later withToxoplasma was higher than in mice infected withToxoplasma alone, while mice infected withToxoplasma and challenged 4–14 days later withTrichinella had lower worm burdens in the intestine than animals infected withTrichinella alone. Greater loss in body weight was observed in mice infected with both parasites than in those infected with either parasite alone.     

Interaction of ivermectin with γ-aminobutyric acid receptors in Trichinella spiralis muscle larvae

The value of the γ-aminobutyric acid (GABA) receptor of nematodes as a target for ivermectin's mode of action remains unclear. Using binding assays, we examined extracts from Trichinella spiralis muscle larvae for the presence of [³H]-ivermectin and [³H]-GABA binding sites. Tissue preparations displayed affinity binding sites for [³H]-ivermectin with a dissociation constant (K _d) of 83 nM and a receptor density (B_max) of 145 fmol/mg protein. We also identified a specific [³H]-GABA binding activity with a K _d of 1.2 μM and a B_max of 4.78 pmol/mg protein. In competition studies, ivermectin was found to be a competitive inhibitor of specific [³H]-GABA binding activity with an inhibition constant (K _i) of 3.39 nM, suggesting that GABA receptors could be implicated in the mechanism of action of ivermectin in nematodes. Received: 7 August 1998 / Accepted: 22 September 1998