湖北部分地区鼠体膜壳绦虫调查

1982～1985年我们在湖北的通山县、应城县、天门县、宜昌县及神农架林区对寄生鼠体而与人有关的微小膜壳绦虫Hymenolepis nana和缩小膜壳绦虫Hymenolepis dininuta及鼠体外寄生蚤类进行了调查。方法将捕到的鼠进行编号,种类鉴定,解剖观察。如阳性取出虫体鉴定虫种。对鼠体外寄生蚤进行收集并鉴定种类,观察体内是否有自然感染的似囊尾蚴。结果在582只鼠中共检出阳性鼠165只,阳性率28.3%。其中微小膜壳绦虫的阳性率为11.8%(69/165),缩小膜壳绦虫阳性率为19.0%(111/165)。在阳性鼠中同时感染两种膜壳绦虫者有15只,阳性率2.5%(15/165)。各地区…     

膜壳绦虫属二新种(绦虫纲:圆叶目:膜壳科)

本文记述膜壳科膜壳属绦虫二新种,即卷尾膜壳绦虫Ｈｙｍｅｎｏｌｅｐｉｓ ｃｈｉｂｉａｅ ｓｐ．ｎｏｖ．和三宝鸟膜壳绦虫Ｈ．ａｂｕｎｄｕｓ ｓｐ．ｎｏｖ．卷尾膜壳绦虫标本采自福州的黑发冠卷属Ｃｈｉｂｉａ Ｈｏｔｔｅｎｔｏｔｔａ Ｂｒｅｖｉｒｏｓｔｒｉｓ;三宝鸟膜壳绦虫标本采自福州的三宝鸟Ｅｕｒｙｓｔ９ｏｍｕｓ ｏｒｉｅｎｔａｌｉｓ ａｂｕｎｄｕｓ均为肠道寄生虫。     

多房棘球绦虫光镜及扫描电镜的观察

本文对甘肃漳县草滩乡家犬小肠所获检的棘球绦虫,做了光镜及扫描电镜(SEM)观察。根据其形态特征及流行病学资料,初步认定为多房棘球绦虫(Echinococcus multicularis)。对扫描电镜所记述的多房棘球绦虫成虫不同部位的表面微毛的形态结构做了较为详细的观察和比较;此外还观察了成熟节片侧缘生殖孔及孕节片内虫卵表面的超微结构。     

安徽省泾县发现缩小膜壳绦虫和链形多头绦虫幼

1985—1986年,我们在泾县包合乡血吸虫病流行病学调查中,发现有可感染于人的缩小膜壳绦虫(成虫)及其终宿主黑线姬鼠、黄胸鼠和链形多头绦虫(蚴虫)及其中间宿主野兔,是安徽省的新发现。 一、缩小膜壳绦虫(长膜壳绦虫)[Hymenolepis diminuta]取自1985年1月15日和1986年1月15日采到的两只黑线姬鼠(Apodemus agrarius),和1986年1月13日采到     

长膜壳绦虫形态及生殖器官畸形的观察

长膜壳绦虫[Hymenolepis diminuta(Rudolphi,1819)]是一种重要的人兽共患寄生虫。1990—1991年我们在雅安市大足鼠(Rattus nitidus Hodgson)、黑线姬鼠(Apodemus agrariusPallas)和褐家鼠(Rattus norvegicus Berkenhout)体内查到此虫种,将3种鼠体内的10条完整虫体用70%酒精固定,用苏木素—卡红染色制片作形态观察。在观察绦虫内部形态过程中,     

寄生在鲤鱼及草(鲩)鱼的鱊头槽绦虫的多样性

研究了寄生于鲤鱼及草(鲩)鱼的鱊头槽绦虫(Bothriocephalus acheiloghathi)的多样性.作者在1986-2000年收集材料,遍及中国19个省及自治区.在江苏等5省只收集到其它寄生虫的材料,故结果未列入附录1和2.研究结果表明,鲤鱼及草鱼的寄生鱊头槽绦虫的地理分布截然不同.寄生于鲤鱼的鱊头槽绦虫分布于黄河水系的西北地区及黑龙江水系的东北各省及长江上游的四川、云南和贵州,南方各省的鲤鱼不感染这种绦虫.寄生于草鱼的鱊头槽绦虫分布于沿珠江水系的广东、广西及闽江水系的福建,感染池塘的幼龄草鱼,天然水体中未发现感染阳性的草鱼.交义感染试验表明,寄生在这两种鲤科鱼类的头槽绦虫有极强的宿主特异性,草鱼感染的头槽绦虫一年内大部分时间排出发育完全的胚胎卵,而鲤鱼感染的头槽绦虫排出的虫卵多为早期分裂卵,甚至在盛夏,水温在28℃-30℃的情况下也无例外.虫卵发育程度不同,卵的孵化期也有差异.在同等温度28℃-29℃时,草鱼头槽绦虫虫卵的孵化期为1.69±0.17 d;鲤鱼的头槽绦虫虫卵的孵化期为3.98±0.3 d.此外,种群结构也有明显区别,草鱼的头槽绦虫在繁殖季节,体长＜1 cm的幼虫占种群的主体,年终时绦虫全部从宿主体内消失,生活周期从初染至消敛约1年;鲤鱼的头槽绦虫主体全年皆为孕节成虫,在Ⅱ龄商品鱼中继续繁殖.本研究表明,鲤鱼及草鱼的寄生鱊头槽绦虫显示的多样性是因长期适应不同生活环境从而演化为两个不同的亚种[动物学报 53(3):470-480,2007].     

泡型包虫病的易感性与抵抗性

流行病学显示,血清中特异性抗原阳性表示感染过泡性包虫病,对于已经感染的患者,他们对多房棘球绦虫的再次感染是有部分免疫。多房棘球绦虫感染人体会产生三种结果:(1)血清学指标证明曾经感染过,但没有出现肝脏病变。(2)在感染后5-15年才出现临床症状。(3)机体出现免疫缺陷后,多房棘球绦虫会快速增殖,包虫的代谢产物会使机体的免疫调节系统紊乱。免疫调节因子IL-10,TGF-β在驱动泡型包虫病患者的T细胞免疫应答发挥了至关重要的作用。在多房棘球绦虫的抵抗性研究中发现了一种新的CD4+CD25+调节性T细胞的效应分子fgl2。     

膜壳科绦虫一新种(绦虫纲:圆叶目)

报道啮齿类绦虫一新种,定名为锡盟啮壳绦虫。文中对新种形态特征进行了详细描述并与近似种作了比较,模式标本保存于中国科学院动物研究所。     

绦虫类细胞遗传学研究

缩小膜壳绦虫（Hymenolepis diminuta,长 膜壳绦虫）的染色体研究,国外已有报告（Jon es, 19451"; Kisner 1957E"; Douglas, 1962E'3）认为 该虫染色体数目为2n=12,但均未作染色体 组型分析。国内尚未见报道。本文采用秋水仙 素短期体外培养— 低渗处理— 空气干燥技 术,研究了缩小膜壳绦虫的染色体组型,现将结 果报告如下：     

绦虫类细胞遗传学研究 Ⅰ.缩小膜壳绦虫的染色体组型

缩小膜壳绦虫(Hymenolepis diminuta,长膜壳绦虫)的染色体研究,国外已有报告(Jones,1945;Kisner 1957;Douglas,1962)认为该虫染色体数目为2n=12,但均未作染色体组型分析。国内尚未见报道。本文采用秋水仙素短期体外培养——低渗处理——空气干燥技术,研究了缩小膜壳绦虫的染色体组型,现将结果报告如下:     

Hymenolepis nana: intestinal tissue phase in actively immunized mice.

We investigated the fate of the intestinal cestode Hymenolepis nana in immunized mice. Immunity was induced by infection with the parasite eggs. These immunized animals and unimmunized controls were then challenged with 50,000 H. nana eggs. The mice were killed 4 to 90 hr after challenge, and H. nana in the intestinal tissue were counted. At 4 hr after challenge the unimmunized and immunized animals had approximately equal numbers of oncospheres. By 12 hr there were fewer parasites in the immunized than in the unimmunized animals. At 90 hr, no H. nana were seen in the immunized mice, whereas in the unimmunized animals the median number of cysticercoids was more than 1,000. It appears, therefore, that in mice well immunized to H. nana by infection, challenge oncospheres can burrow into the intestinal tissue before they are killed. The reduced number of oncospheres in the immunized mice 12 hr after challenge, and the accumulation of eosinophils near individual oncospheres still present, indicate that an immune response to the parasite was taking place. Absence of a lymphocyte infiltration near any of the oncospheres suggests that the mechanism of immunity was not lymphocyte mediated; thus, the histopathology of the reaction is consistent with that of humoral immunity.     

Innate and Learned Predator Recognition Mediated by Chemical Signals in Eurycea nana

Effective and efficient predator recognition and avoidance are essential for the persistence of prey populations, especially in habitats where non-native predators have been introduced. Predator recognition studies are commonly couched within a learned or innate dichotomous framework; however, characteristics of some systems or species could favor innate recognition combined with the ability to alter avoidance responses based on experience with predators. Eurycea nana is a fully aquatic salamander inhabiting a system with a diverse, yet temporally stable, community of native and non-native opportunistically foraging fish predators. To examine predator recognition, we examined avoidance responses (decreased activity) of predator-naïve (first-generation, captive-reared) and predator-experienced (recently collected) E. nana to the chemical cues of a native predator, a non-native predator, a non-predator, and a blank control. Both predator-naïve and predator-experienced E. nana significantly lowered activity in response to the native fish predator when compared with a blank control. Interestingly, predator-naïve E. nana decreased activity in response to the non-native fish predator while predator-experienced E. nana did not. These results indicate that while there is an innate component to predator recognition in E. nana , experience and risk assessment may also be important.     

The effect of geographic range and dichogamy on genetic variability and population genetic structure in Tricyrtis section Flavae

Populations of each of the four species of Tricyrtis sect. Flavae were sampled using enzyme electrophoresis to examine the effect of geographic range and dichogamy on the genetic diversity of the species. The most widespread species, T. nana, had the lowest level of genetic diversity at both the population and the species level. The depauperate genetic diversity at the population level of T. nana appears to result from the high self-fertilization of the species. The low genetic diversity at the species level of T. nana probably resulted from the bottleneck effect during the speciation process in which this species diverged from the progenitor species, T. flava. Genetic differentiation among populations was high in both adichogamous T. nana and protandrous T. flava. High self-fertilization in T. nana and the colonizing nature of T. flava are likely the main factors causing the differentiated population genetic structure. In contrast to a previous study on chloroplast DNA (cpDNA) variation in Tricyrtis sect. Flavae, T. nana was most closely related to T. flava, which corresponds to the morphological resemblance of both species.     

Hymenolepis diminuta and H. nana: cross immunity against the lumen phase in BALB/c mice

When BALB/c mice initially given cysticercoids of Hymenolepis diminuta orally (Day 0) were challenged with eggs or cysticercoids of H. nana, almost all the mice became completely resistant to H. nana challenges from Day 30 onward, and no luminal adults of H. nana were established. There was a tendency for the number of tissue cysticercoids recovered 4 days after egg challenge in immunized mice to be much less than that in control mice (P less than 0.001, Student's t test). However, when these cysticercoids recovered from immune group mice were inoculated into uninfected mice, they matured in the lumen. Thus, the cross immunity to H. nana challenge evoked by an initial prepatent infection with H. diminuta appeared to be directed not against the tissue phase but against the lumen phase of H. nana. When BALB/c mice initially given eggs of H. nana were challenged with H. diminuta, they became resistant to H. diminuta from Day 15 onward. When the mice given eggs of H. nana were treated with a cestocide, praziquantel, at the beginning of the expected luminal development of H. nana and experienced a tissue phase only before challenge with H. diminuta, they showed no resistance to H. diminuta. Thus, the cross immunity to H. diminuta challenge evoked by an initial patent infection with H. nana appeared to be due to the immunogens of the lumen phase of H. nana but not those of the tissue phase. The cross immunity may be, therefore, essentially evoked by the lumen phase of these two phylogenetically closely related species and not by or against the tissue phase of H. nana.(ABSTRACT TRUNCATED AT 250 WORDS)     

Morphological, cytogenetic, and molecular evidence for introgressive hybridization in birch.

Extensive morphological variation of tetraploid birch (Betula pubescens) in Iceland is believed to be due to gene flow from diploid dwarf birch (B. nana) by means of introgressive hybridization. A combined morphological and cytogenetic approach was used to investigate this phenomenon in two geographically separated populations of natural birch woodland in Iceland. The results not only confirmed introgressive hybridization in birch, but also revealed bidirectional gene flow between the two species via triploid interspecific hybrids. The populations showed continuous morphological variation connecting the species, but karyotypically they consisted of only three types of plants: diploids, triploids, and tetraploids. No aneuploids were found. Some of the tetraploid plants had B. pubescens morphology as expected, but most of them had intermediate characters. Most of the diploid plants were B. nana, but some were intermediates and a few had B. pubescens morphology. The triploid plants were either intermediates or they resembled one of the two species. Similar introgressive variation was observed among the diploid and triploid progeny of open-pollinated B. nana in a garden. Birch samples including field plants and artificial hybrids were further examined using a molecular method based on genomic Southern hybridization. The experiments verified introgression at the DNA level.     

Hymenolepis nana: immunity against oncosphere challenge in mice previously given viable or non-viable oncospheres of H. nana, H. diminuta, H. microstoma and Taenia taeniaeformis

When mice, previously given oral inoculation with viable oncospheres of the heterologous cestode species (Hymenolepis diminuta, H. microstoma, Taenia taeniaeformis) and the homologous one (H. nana), were challenged with oncospheres of H. nana 4 days after the primary inoculation, they showed strong and complete resistance to H. nana challenge, respectively. However, the resistance was not evoked in mice given either infective eggs of Toxocara canis or non-viable oncospheres of all cestode species examined. Congenitally athymic nude mice given viable oncospheres did not show any resistance to H. nana either. Eosinophil infiltration around cysticercoids of H. nana in the intestinal villi appeared to be more prominent in mice previously given viable oncospheres of H. diminuta than in mice given non-viable oncospheres or PBS only. Some of the eosinophils in the villus harboring cysticercoid(s) of H. nana invaded the epithelia in the former, whereas all eosinophils remained in the lamina propria in the latter. There was almost no eosinophil infiltration in nude mice. Microscopic observations revealed that oncospheres of H. diminuta, which require beetles as the intermediate host like H. microstoma, could invade the mouse intestinal tissue. Therefore, it is strongly suggested that the strong cross resistance to H. nana in mice, induced by oncospheres of all heterologous cestode species, is thymus-dependent and due to oncospheral invasion into the intestinal tissue of mice.     

Specific cross-immunity between Hymenolepis nana and H. diminuta: immunization with heterologous and homologous light infections

The consequences of previous and concurrent infection with two related species of cestodes, Hymenolepis nana and H. diminuta, were studied in CD1 mice. A H. diminuta infection strongly affected the establishment and the survival of a secondary H. nana egg or cyst infection administered 30 days later. An infection of 20 H. nana eggs strongly protected against a 5-cyst H. diminuta challenge, whereas an infection of 10 H. nana cysts was ineffective; 20 H. nana eggs also protected against a challenge with 5 cysts of H. diminuta administered 5 days later. No effects were observed in either parasite during a concurrent infection established by administration of cysts. An H. nana egg-infection was unable to affect the establishment of a secondary H. nana cyst-infection given 1 month later; however a significant decrease in growth was found. Similar results were found when a primary H. nana egg-infection was followed 5 days later by the homologous cyst-infection. But an infection with 5 H. nana cysts was unable to protect against a homologous challenge of 5 cysts or 200 eggs. The reciprocal cross immunity between the heterologous parasites and the failure of protection of homologous challenges are discussed in relation to light infections.     

Intestinal parasites in southeast Asian refugees two years after immigration.

We collected stool specimens from 2,520 Southeast Asian refugees who had resided in the United States for an average of 2.1 years. More than half reported receiving prior treatment of parasites. At least one parasite was discovered in 32%, and multiple parasites were found in 8% of patients. Hookworm, Giardia, Strongyloides, and Hymenolepis nana were most commonly found. In comparison to studies done at the time of immigration, all parasites had decreased in frequency, but Giardia, hookworm, and H nana remain common. Although initial screening efforts may have failed to identify substantial numbers of infected refugees, poor compliance with treatment may also explain the persistence of intestinal parasites in our patients. The continued presence of Giardia and H nana, especially among children, may be explained by person-to-person transmission or autoinfection.     

Life-history traits in closely related secondary parasitoids sharing the same primary parasitoid host: evolutionary opportunities and constraints

Thus far, few studies have compared life-history traits amongst secondary parasitoids attacking and developing in cocoons of their primary parasitoid hosts. This study examines development and reproduction in Lysibia nana Gravenhorst and Acrolyta nens Hartig (both Hymenoptera: Ichneumonidae), two related and morphologically similar secondary parasitoids that attack pupae of the gregarious endoparasitoid, Cotesia glomerata L. (Hymenoptera: Braconidae). On black mustard, Brassica nigra L. (Brassicaceae) plants in a field plot, adults of L. nana and A. nens frequently emerged from the same cocoon broods of C. glomerata . Based on similarities in their phylogeny and morphology, it was hypothesized that both species would exhibit considerable overlap in other life-history traits. In both L. nana and A. nens , adult wasp size increased with host cocoon mass at parasitism, although L. nana wasps were slightly larger than A. nens wasps, and completed their development earlier. Adult females of both species emerged with no eggs but matured eggs at similar rates over the following days. When provided with 20 host cocoons daily, fecundity in female L. nana was slightly more skewed towards early life than in A. nens , although lifetime fecundity did not differ between the two species. Longevity was significantly reduced in females of both species that were provided with hosts. Both parasitoids were found to exhibit strong similarities in life-history and development traits and in their ecological niche, thereby supporting our general hypothesis. Competition between L. nana and A. nens is presumably diffused because their preferred host ( C. glomerata ) is relatively abundant in open habitats.     

Anthelmintic effects of bithionol, paromomycin sulphate, flubendazole and mebendazole on mature and immature Hymenolepis nana in mice

The anthelmintic effects of anti-tapeworm drugs, bithionol, paromomycin sulphate, flubendazole and mebendazole on immature and mature Hymenolepis nana in mice were compared. Immature worms were not affected by paromomycin sulphate or flubendazole administered for 12 consecutive days (days one to 12 after infection) at 100 mg/kg/day but 48% and 100% of H. nana were eliminated from mice by bithionol and mebendazole respectively, at the same dosage regimen. Bithionol, paromomycin sulphate, flubendazole and mebendazole given at 100 mg/kg/day for five consecutive days (days 12 to 16 after infection) eliminated 32%, 29%, 36% and 100% of mature worms respectively. 10 and 20 mg of mebendazole/kg/day for five consecutive days (days 12 to 16 after infection) had little effect on mature worms whereas 50 and 100 mg/kg/day for the same period eliminated 99% and 100% of mature worms, respectively. ED50 of mebendazole in the elimination of mature H. nana was 14 or 15 mg/kg/day for five days from the reduction in dry weight or in number of worms recovered respectively. The effects of mebendazole given 2 to 4 days, 8 to 10 days or 13 to 15 days after infection at 100 mg/kg/day were compared. Very low, if any, activity of the drug given 2 to 4 days after infection was seen, whereas the drug given 8 to 10 days or 13 to 15 days after infection eliminated 84% and 86% of H. nana respectively.