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PubMed2002

Molecular cloning of a vaccine antigen against infection with the larval stage of Echinococcus multilocularis.

Alveolar and cystic hydatidosis are caused by infection with the larval stages of Echinococcus multilocularis and Echinococcus granulosus, respectively. A host-protective antigen has been identified in E. granulosus. Here we identify the presence of a closely related protein in E. multilocularis, characterize and express a cDNA encoding the antigen (designated EM95), determine the structure of the em95 gene, and demonstrate that the EM95 recombinant protein can be used to induce significant levels of protection against challenge infection with E. multilocularis eggs in mice.

Adjuvants, Immunologic↗

PubMed2000

[Isoelectric focusing analysis of Echinococcus multilocularis protoscolex antigens].

OBJECTIVE: To understand the components of the crude antigens of Echinococcus multilocularis protoscoleces. METHODS: Isoelectric focusing was carried out to fractionate the protein components of E. multilocularis protoscoleces. The individual fractions were collected and subjected to SDS-PAGE, the gels were analyzed by a gel analysis system. RESULTS: The pI values of individual fractions varied from 4.0 to 8.5, while the molecule weights of main protein bands were 72/73, 62/63, 42/44, 35/36, 34 and 21/22 kDa. CONCLUSION: An alternative separation method of crude antigens of Echinococcus multilocularis was established.

Animals↗

PubMed2005

Mathematical modeling of Echinococcus multilocularis transmission.

A mathematical model for the transmission cycle of Echinococcus multilocularis would be useful for estimating its prevalence, and the model simulation can be instrumental in designing various control strategies. This review focuses on the epidemiological factors in the E. multilocularis transmission cycle and the recent advances of mathematical models for E. multilocularis transmission.

Animals↗

PubMed2006

Comparative development of Echinococcus multilocularis in its definitive hosts.

The comparative development of Echinococcus multilocularis was studied in its definitive hosts, the fox, dog, cat and raccoon dog, beyond the pre-patent period to 90 days post-infection. All host species, apart from cats were susceptible to infection and capable of supporting substantial worm burdens. Although worms in cats matured and produced thick-shelled eggs, their overall development was retarded compared to that in other species in which the parasite matured rapidly producing large populations of gravid worms. E. multilocularis matured rapidly in foxes and raccoon dogs and this was sustained in raccoon dogs but not in foxes in which maturation of worms declined during the later stages of infection, in contrast to that in both raccoon dogs and dogs. These populations were sustained for longer in raccoon dogs and dogs compared to foxes. Cats would appear to have only a minor role in the maintenance of E. multilocularis in endemic areas, and infections in cats may be of minimal public health significance. In contrast, foxes, dogs and the recently recognized definitive host the raccoon dog, are all capable of playing significant roles in the epidemiology of alveolar echinococcosis. This study also demonstrated that the developmental processes of growth, segmentation, proglottization and maturation in adult Echinococcus are independent and can be influenced by environmental factors thus confirming earlier in vitro observations.

Animals↗

PubMed2004

Echinococcus multilocularis laminated-layer components and the E14t 14-3-3 recombinant protein decrease NO production by activated rat macrophages in vitro.

Echinococcus multilocularis and Echinococcus granulosus cause alveolar and cystic (unilocular) echinococcosis, respectively, in humans and animals. It is known that these parasites can affect, among other molecules, nitric oxide (NO) production by periparasitic host cells. Nevertheless, detailed dissection of parasite components specifically affecting cell NO production has not been done to date. We compare the effect of E. granulosus and E. multilocularis defined metacestode structural (laminated-layer associated) and metabolic (14-3-3 protein, potentially related with E. multilocularis metacestode tumor-like growth) components on the NO production by rat alveolar macrophages in vitro. Our results showed that none of these antigens could stimulate macrophage NO production in vitro. However, a reversed effect of some Echinococcus antigens on NO in vitro production was found when cells were previously exposed to LPS stimulation. This inhibitory effect was found when E. multilocularis laminated-layer (LL) or cyst wall (CW) soluble components from both species were used. Pre-stimulation of cells with LPS also resulted in a strong, dose-dependent reduction of NO and iNOS mRNA production after incubation of cells with the E14t protein. Thus, the E. multilocularis 14-3-3 protein appears to be one of the components accounting for the suppressive effect of the CW and LL metacestode extracts.

14-3-3 Proteins↗

PubMed2005

A new technique to avoid losing the strains of Echinococcus multilocularis during passaging.

OBJECTIVE: To examine the survival of Echinococcus multilocularis (E. multilocularis) and the formation of protoscoleces, under refrigerated conditions over a 43-day observation period. METHODS: We conducted this study in Ege University, School of Medicine, from May-December, 2004. We included 4 healthy females and 2 males, 8-12 week old M. unguiculatus species (approximately 60-70 gr) for the study, as they are known to be susceptible to E. multilocularis. In this experimental study, we aimed to define a technique to keep the strains during these passages. RESULTS: We found preserved viability and virulence of E. multilocularis stored in RPMI 1640 plus 10% fetal calf serum at +4 degrees C. We accomplished the infection of the Meriones unguiculatus after in-vivo passaging from that flask, which we kept at +4 degrees C, and this proves the viability of protoscoleces and membranous structures perfectly at the 43rd day. CONCLUSION: We also found that E. multilocularis metacestodes and the formation of protoscoleces keep their viability up to 60 days and virulence up to 43 days under this condition. We recommend storing an extra flask during each passage as a precaution against losing strains.

Animals↗

PubMed2003

Pro-inflammatory (IL-1beta, IL-18) cytokines and IL-8 chemokine release by PBMC in response to Echinococcus multilocularis metacestode vesicles.

In humans infected with Echinococcus multilocularis, larval metacestodes will develop, proliferate and progressively infiltrate the surrounding host tissues by exogenous budding of parasitic microvesicles or cell lines which detach from the original tumour and thus become transported through blood or lymph vessels into other organs. Cellular effector mechanisms constitute the most effective means to restrict parasite persistence and proliferation, and here we demonstrate that E. multilocularis vesicle antigens will induce pro-inflammatory, regulatory and chemokine release by PBMC from patients. The pro-inflammatory cytokines IL-1beta and IL-18 were reduced in echinococcosis patients, regulatory IL-10 was similar, but parasite vesicle-induced IL-8 was dominant and clearly elevated in patients. Such selective and opposite dynamics of inflammatory cytokines and chemokine release may prevent overwhelming and pathogenic inflammation, and constitute an appropriate response for attraction of effector cells into the periparasitic tissues with the capacity to limit E. multilocularis metacestode proliferation and dissemination.

Animals↗

PubMed1996

Parenteral strobilar development of Echinococcus multilocularis in scid mice.

Parenteral strobilation of Echinococcus multilocularis was observed in acid (severe combined immuno-deficient) mice after intracerebral, subcutaneous and intraperitoneal inoculation with protoscoleces. Evaginated protoscoleces and segmented worms were obtained at the inoculated sites. Most worms recovered from peritoneal cavity of scid mice were encapsulated by connective tissue and granulocytes but showed a maximum of 3 proglottids, elongation of genital primordia and vesiculation. Viability of worms recovered from the subcutaneous tissue and peritoneal cavity of scid mice were higher (69.1-91.4%) than those from the immunologically normal C.B-17 (4.0-48.0%) control mice. However, viabilities of worms from the cerebrum of both scid and C.B-17 were almost the same (87.7-94.4%). Worms recovered from scid mice showed further development of reproductive organs when transplanted into the small intestine of prednisolone treated golden hamster. These findings suggest that the parenteral milieu of scid mice allows adult development of E. multilocularis protoscoleces.

Animals↗

PubMed1998

Purine metabolism in Echinococcus multilocularis.

The activities of the enzymes in Echinococcus multilocularis metacestodes involved in purine salvage were studied by HPLC. As in most parasites, this cestode relies entirely on salvage of preformed bases and nucleosides for its purine requirement. Therefore, these enzymes may be targets for drugs in the chemotherapeutic treatment of diseases caused by this parasite. The animals used in this study were gerbils (Meriones unguiculatus). Enzyme activities from sera and hepatic tissue in control and infected animals were similar with the exception of adenine phosphoribosyltransferase which showed an activity 4-fold greater in the serum from control than in serum from infected animals. In the parasite, adenine and hypoxanthine-guanine phosphoribosyltransferases and adenosine deaminase had the highest activities. Therefore, in E. multilocularis metacestodes, this pathway seems to be important for the parasite's metabolism.

Adenine Phosphoribosyltransferase↗

PubMed1995

Influence of environmental factors on the infectivity of Echinococcus multilocularis eggs.

The sensitivity of eggs of Echinococcus multilocularis to environmental and controlled laboratory conditions was tested. Egg material was exposed and the infectivity was subsequently monitored by in vitro activation and by oral infection of the natural host, Microtus arvalis. To study the impact of environmental conditions in an endemic area of south-western Germany, eggs were sealed into bags of nylon mesh and exposed to the natural climate during various seasons. The maximal survival time of eggs was 240 days in an experiment performed in autumn and winter and 78 days in summer. A study of the tenacity of eggs under laboratory conditions revealed a high sensitivity to elevated temperatures and to desiccation. At 45 degrees C and 85-95% relative humidity the infectivity was lost after 3 h as well as after 4 h exposure to 43 degrees C suspended in water. Exposure to 27% relative humidity at 25 degrees C as well as exposure to 15% relative humidity at 43 degrees C resulted in a total loss of infectivity within 48 and 2 h, respectively. Temperatures of 4 degrees C and of -18 degrees C were well tolerated (478 days and 240 days survival, respectively), whereas exposure to -83 degrees C and to -196 degrees C quickly killed off the eggs (within 48 h and 20 h, respectively). Eggs of E. multilocularis were not killed off by exposure to various commercially available disinfectants applied according to the manufacturers' instructions and by exposure for 24 h to low concentrations of ethanol. Irradiation with 40 krad. from a 137Caesium source prevented the development of metacestodes but allowed seroconversion of infected rodents.

Animals↗

PubMed1979

Humoral response to sheep red blood cells in C57L/J mice during early and chronic stages of infection with Echinococcus multilocularis cysts.

C57L/J male mice infected with Echinococcus multilocularis cysts were challenged intraperitoneally at 4, 8, and 12 weeks postinfection (p.i.) with 3 x 10(9) sheep erythrocytes. The direct plaque forming cells, 2-mercaptoethanol (2-ME) sensitive (4-day sera) and 2-ME-resistant (8-day sera) haemagglutinin responses were significantly elevated at eight and 12 weeks p.i. as compared to controls or the fourweeks postinfected mice. Possible mechanisms of immunopotentiation in the chronically infected mice is discussed in relation to the larval cyst mass, splenomegaly, and B cell hyperplasia in the lymphoid tissues during the course of infection.

Animals↗

PubMed1990

Glycosphingolipids of Echinococcus multilocularis metacestodes.

Neutral and acid glycosphingolipids of Echinococcus multilocularis metacestodes that were obtained after intraperitoneal infection of Meriones unguiculatus have been analyzed by thin layer chromatography. Neutral and acid glycosphingolipids accounted for 95% and 5% of total glycosphingolipids, respectively. 12 different fractions were observed in the neutral glycosphingolipids extracts of the parasite. The most important was a monohexosylceramide fraction accounting for 56.4% of neutral glycosphingolipids. 9 different fractions were detected in gangliosides (acid glycosphingolipids). The fact that these glycosphingolipids were specific to the parasite was established by the analysis of different cell populations of the host. Glycosphingolipids were purified from control and parasite-infected gerbil blood cells as well as from peritoneal exudate cells of healthy gerbils after a non-specific immunostimulation. The chromatograms obtained with these extracts were totally different from the parasite. In addition, parasitosis was found to have no effect on the host blood cell glycosphingolipids.

Animals↗

PubMed1992

Glycosphingolipids with Gal beta 1----6Gal sequences in metacestodes of the parasite Echinococcus multilocularis.

Neutral glycosphingolipids of the metacestodes of Echinococcus multilocularis, an animal and human parasite, were resolved by high performance thin layer chromatography into 12 fractions. Nine of these fractions were permethylated, analyzed by electron impact-mass spectrometry, and submitted to methylation analysis by gas chromatography-mass spectrometry. Native fractions were analyzed by liquid secondary ion-mass spectrometry and degraded sequentially by exoglycosidases. In addition to a previously described galactosylceramide, a di-, a tri-, and a tetragalactosyl-ceramide having Gal beta 1-6Gal internal linkages were characterized. This type of carbohydrate chain has been described in glycolipids of a marine mollusk, Turbo cornutus (Matsubara, T., and Hayashi, A. (1981) J. Biochem. (Tokyo), 89, 645-650). In addition two novel fucolipids were found with the following structures: Fuc alpha 1-3Gal beta 1-6Gal-Cer and Gal beta 1-6(Fuc alpha 1-3)Gal beta 1-6Gal-Cer. Ceramides contained sphinganine and either nonhydroxy fatty acids with 16, 18, 26, and 28 carbon atoms, or hydroxy fatty acids, with 16 and 18 carbon atoms. Di-, tri-, and tetragalactosylceramides containing the Gal beta 1-6Gal disaccharide were found to be immunogenic in humans.

Animals↗

PubMedDate not supplied

[Echinococcus multilocularis in red foxes in Saxony-Anhalt: identification of areas of increased risk of infestation and association of the infestation probability with the average annual maximum temperature].

Between 1998 and 2004 1341 Red Foxes from 611 locations were examined parasitologically for Echinococcus multilocularis at the State Office of Consumer Protection Saxony-Anhalt. Examination was carried out in parallel to rabies monitoring. A period-prevalence of 9.2% of infestation was found. Employing a Scan Statistic a large area in the southwest of the federal state and two smaller areas of increased risk with respect to infestation with Echinococcus multilocularis were identified. The hypothesis of a negative association of the probability of infestation with the average annual maximum temperature of the location where the foxes were shot was supported by logistic regression analysis. A decreased probability of inactivation of Echinococcus multilocularis-oncospheres through heat and desiccation in areas of lower average annual maximum temperature seems to be likely.Thus, the infection pressure increases with reduced temperatures.

Animals↗

PubMed1993

Synthesis of epoxypropyloxy chromones and allyl hydroxy chromones and in vitro-in vivo activity on protoscoleces of Echinococcus multilocularis (Cestoda).

Derivatives with epoxypropyloxy, allyloxy and allyl hydroxychromone structures were synthesized and tested against protoscoleces of Echinococcus multilocularis. Compounds IV-IX were tested in vitro and compound VII proved the most active of them with, at 0.1 mmol.L-1, 98% dead protoscoleces in open vesicles after 24 hours and 80% in closed vesicles within 96 hours. Compound VII was tested in vivo on Meriones unguiculatus infested by Echinococcus multilocularis, but was found to be rather inactive.

Animals↗

PubMed2003

A model for the transmission of Echinococcus multilocularis in Hokkaido, Japan.

A mathematical model for Echinococcus multilocularis transmission would be useful for estimating its prevalence and determining control strategies. We propose a mathematical model which quantitatively describes the transmission of E. multilocularis in Hokkaido, Japan. The model takes into account the influence of the dynamics of both the definitive and the intermediate host populations, which show large scale seasonal variation as they are wild animals. The simulations based on the model clarify the mechanism of seasonal transmission of E. multilocularis quantitatively, notwithstanding a lack of seasonal prevalence data. At present, human alveolar echinococcosis is prevalent throughout the mainland of Hokkaido. The risk of being infected in the human population has been investigated by analyzing the seasonal fluctuation in parasite egg dispersion in the environment. This is necessary for the planning of more suitable preventive measures against E. multilocularis.

Animals↗

PubMed1989

[Echinococcus multilocularis in a swamp beaver (Myocaster coypus)].

Larval Echinococcus multilocularis was found in a nutria (Myocastor coypus) on a fur farm situated south of the Thuringian Forest near the border the Federal Republic of Germany. This finding is of epidemiological importance. Investigations of 67 red foxes (Vulpes vulpes) originating from this area and the whole Erfurt Region (Thuringia) did not reveal the presence of adult E. multilocularis.

Animals↗

PubMed2005

Characterization of various recombinant antigens from Echinococcus multilocularis for use in the immunodiagnosis.

Using four clones isolated from Echinococcus multilocularis cDNA library with alveolar echinococcosis (AE) patient sera, various antigens were expressed as ThioHis tag-fused protein. Recombinant EmII/3 antigen was produced as the five fragments divided into the N-terminal (#5 and #5s), the central (#6 and #6s) and the C-terminal domain (#7). Immunoblot analysis revealed that the #7 showed significant reactivity whereas those of #5 and #5s were relatively low. The #6 and #6s also showed lower reactivity than that of #7, although the two minor bands of #6 reacted with every serum. These results suggested that an immunodominant region of EmII/3 locate within the C-terminal one third. The #8s recombinant antigen, Ser23-Glu176 of actin filament fragmenting protein (AFFP), apparently reacted with the AE patient sera, while the #1 antigen synthesized as a full-length antigen BI did not show such high reactivity. Thus, #7 and #8s antigens showed significant potential for use in immunodetection of AE. In addition, the specific antibodies against #7 and #8s reacted with specific antigens in crude extract of E. multilocularis cyst, indicating that these antigens retained antigenicity common to native EmII/3 and AFFP, respectively.

Animals↗