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PubMed1994

Antibody responses in the wild vole, Clethrionomys rufocanus bedfordiae, naturally infected with Echinococcus multilocularis by western blotting.

Antibody responses against crude antigens and the two (Em18 and Em16) epitopes of Echinococcus multilocularis were analysed by Western blotting using sera from the wild vole, Clethrionomys rufocanus bedfordiae (Crb), which were captured in Hokkaido, Japan and found to have been naturally infected with eggs, and compared with those in patients of AHD and mice experimentally infected with protoscoleces of this parasite. Antibody responses in the wild were demonstrated most clearly with anti-Crb-IgG antiserum but more faintly with anti-rat-IgG antiserum and poorly with anti-mouse-IgG or anti-human-IgG antisera or Protein G. Although only two serum samples of the wild vole found naturally infected were analysed, antibody responses against Em18 and Em16 in these voles appeared to be similar to those in AHD patients but differed from those in mice.

Animals↗
PubMed1994

Enhanced larval cyst growth of Echinococcus multilocularis in praziquantel-treated jirds (Meriones unguiculatus).

Jirds (Meriones unguiculatus) inoculated intraperitoneally with cystic material of Echinococcus multilocularis were given daily oral treatments of praziquantel at 300 mg/kg of body weight (bw) or dimethyl sulfoxide vehicle for five-day treatment regimens starting at 29 days postinoculation (PI) up to 69 days PI. At 39 or 49 days PI, the growth of the larval cystic mass (LCM) in jirds following a single or two five-day treatment regimens was significantly enhanced (P < 0.05) by 129.0% (2.3-fold) or 102.9% (2.0-fold), respectively. At 59 or 69 days PI following three or four five-day treatments with praziquantel, LCM growth was enhanced by 47.8% (1.5-fold) and 44.1% (1.4-fold), respectively, but was no longer significantly different than that in control jirds. A single five-day treatment on 29-33 days PI (with necropsy at 69 days PI) significantly enhanced the growth of the LCM by 87.6% (1.9-fold). Parasites from praziquantel treatment regimens examined ultrastructurally showed consistent damage to the germinal membrane evidenced by vacuolization and rupture of syncytial cytoplasm, rupture and coalescence of the electron-lucent vesicles just below the microvilli of the tegumental surface, and swelling and rounding of mitochondria. At 39 days PI, increased blebbing of the germinal membrane into the lumen of the LCM in praziquantel-treated animals was observed by scanning electron microscopy. The treatment-induced blebs were identified as nucleated germinal cells by transmission electron microscopy and appeared to be responsible for metastasis and enhanced growth of the LCM. Although praziquantel damaged the ultrastructural integrity of the LCM, treatment failed to inhibit larval cyst growth or protoscolex development.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Echinococcus multilocularis: responses to infection in Mongolian gerbils.

Mongolian gerbils (Meriones unguiculatus) inoculated intraperitoneally with three acephalic cysts of Echinococcus multilocularis were very susceptible to infection. Aspects of the responses of gerbils to this infection were examined to determine if they could be related to the progress of the infection. Hematologic changes observed during the infection included anemia, reticulocytosis, lymphocytopenia, neutrophilia, monocytosis, and eosinopenia; these changes were related to the size of the infection. Infected gerbils also produced specific protein-A binding antibodies to E. multilocularis. At 14 weeks after inoculation, infected gerbils showed splenomegaly and somewhat elevated serum transaminase levels, although serum 5'-nucleotidase levels were normal.

Animals↗
PubMedDate not supplied

Metabolic alterations in organs of Meriones unguiculatus infected with Echinococcus multilocularis.

1. 1H-NMR spectra of liver, spleen and kidney extracts from Meriones unguiculatus infected with Echinococcus multilocularis showed decreased levels of glucose. In addition, the liver extracts were severely glycogen-depleted. 2. Both livers and spleens contained less glycine, taurine and acetate. Spleens also had fewer cholines and less lactate but more betaine and alanine. 3. In the kidneys, elevated concentrations of succinate, acetate and lactate were found.

Amino Acids↗
PubMed1997

Secondary Echinococcus multilocularis infection in A/J mice: delayed metacestode development is associated with Th1 cytokine production.

The course of Echinococcus multilocularis infection was studied in four different strains of mice after intrahepatic inoculation of a metacestode homogenate. Among these strains of mice, A/J and BALB/c mice were characterized, respectively, as the most resistant and susceptible strains. Although there was no significant difference between the mean surface of hepatic metacestodes of these two strains of mice at any examination time, 13 weeks after infection, the mean metastatic burden of A/J mice was significantly lower than that of BALB/c mice. Moreover, at this time, some BALB/c mice spontaneously died from their infection whereas all A/J mice remained in good health. The relative resistance of A/J mice to parasite development was associated with a strong and sustained in vitro spleen cell proliferative response to a crude E. multilocularis extract as well as with a high parasite-induced production of IFN-gamma and IL-2. The susceptibility of BALB/c mice was on the contrary associated with a high IL-4 production. Interestingly, the parasite extract also stimulated a significant IL-4 production by spleen cells of uninfected susceptible BALB/c mice, but not by control A/J mouse spleen cells. Altogether, these results suggest that the relative resistance of A/J mice to E. multilocularis growth is associated with the development of T cell responses characterized by the production of high levels of Th1 cytokines.

Animals↗
PubMedDate not supplied

[The "dangerous fox tapeworm" (Echinococcus multilocularis) and alveolar echinococcosis of humans in central Europe].

According to the present status of knowledge, endemic Echinococcus multilocularis infections in foxes (Vulpes vulpes) are known to occur in the following countries of Central Europe: Belgium (southern parts), Luxembourg, France (Massif Central and eastern parts), Switzerland (21 of 26 cantons) Liechtenstein, Austria (6 of 9 provinces), Germany (812 of 16 federal states), and Poland (northern parts). The prevalence rates of E. multilocularis are highly variable regionally and range between > 1 and > 50%. Dogs and cats are rarely infected (mostly < 1%). The incidence of human alveolar echinococcosis (AE) is low in the Central European endemic area with 0.02-1.4 new cases per year and 100,000 inhabitants. While in untreated patients the disease is mostly lethal (lethality up to > 90%) and treatment requires high expenditure, AE is of higher public health significance than indicated by the incidence rates. In addition to these aspects diagnosis, treatment and prophylaxis in final hosts (dogs, cats) and preventive measures for humans are discussed.

Animals↗
PubMed2001

Echinococcus multilocularis on Svalbard: introduction of an intermediate host has enabled the local life-cycle.

The taeniid tapeworm Echinococcus multilocularis is here reported for the first time at the Svalbard Archipelago in the Norwegian Arctic. This new finding is interesting because the establishment of E. multilocularis is due to a recent anthropogenic introduction of its intermediate host--the sibling vole Microtus rossiaemeridionalis at Svalbard. The parasite itself has probably become naturally transferred to Svalbard due to migratory movements of its final host--the arctic fox Alopex lagopus between source areas for E. multilocularis in Siberia and Svalbard. We report macroscopically determined prevalence of E. multilocularis from a sample of 224 voles trapped in August in 1999 and 2000. The prevalence was among the highest ever recorded in intermediate hosts and was dependent on age and sex of the hosts approaching 100% in overwintered males. The high prevalence and the simplicity of the vole-arctic fox-E. multilocularis system at Svalbard makes it an eminent model system for further epidemiological studies.

Animals↗
PubMed1990

Uniform strobilar development of Echinococcus multilocularis in vitro from protoscolex to immature stages.

The aim of this study was to obtain uniformity in strobilar development of Echinococcus multilocularis from protoscoleces in vitro. The isolate of E. multilocularis used was derived initially from a human case in France and subsequently maintained in the laboratory by intraperitoneal passage in Meriones unguiculatus. Protoscoleces used for culture were obtained using preparative procedures in which parasite tissue was disrupted gently with minimal exposure to pepsin and acidic conditions followed by immediate exposure to pancreatin in alkaline solution. Resultant cultures contained large numbers of evaginated, active, vermiform stages, which exhibited uniform strobilar development with formation of the first proglottid and segment and limited maturation of the first proglottid. All worms that exhibited proglottization subsequently segmented. Further proglottization did not occur and all worms degenerated within a few days following segmentation. The results are discussed in light of current knowledge of the relationships of somatic and germinal processes in Echinococcus. In view of these results, further studies should be encouraged to improve strobilar development of E. multilocularis in vitro.

Animals↗
PubMed2001

Geographic information system-aided analysis of factors associated with the spatial distribution of Echinococcus multilocularis infections of foxes.

To investigate the influence of environmental factors on the spatial epidemiology of infections with Echinococcus multilocularis, foxes were sampled in a focal endemic region in the Northwest of Brandenburg, Germany, and examined for infection by the parasite. The locations where foxes were obtained were recorded in a geographic information system database. Positions of infected and uninfected foxes were analyzed on the background of geographic vector data of water, settlements, streets, forests, crop, and pasture. Fox positions were allocated to different land-use classes by use of a Landsat Thematic Mapper (TM) satellite image. Infected foxes were more frequently shot near water, in areas of high soil humidity, and on pastures, suggesting that dryness may limit the tenacity of E. multilocularis oncospheres. Thus open landscapes with humid soil seem to be favorable for the life cycle of the parasite. In contrast, infected foxes were significantly underrepresented in forest areas.

Animals↗
PubMed1989

Cellular immune response in Echinococcus multilocularis infection in humans. I. Lymphocyte reactivity to Echinococcus antigens in patients with alveolar echinococcosis.

The involvement of cellular immunity in alveolar echinococcosis (AE) due to E. multilocularis is strongly suggested by the intense granulomatous infiltration observed around the hepatic parasitic lesions, and a progressive decrease of specific cellular immunity has been described in murine AE. However, specific cellular immunity against E. multilocularis has never been documented in human AE. The reactivity to phytohaemagglutinin (PHA) and E. multilocularis antigens of peripheral blood mononuclear cells (PBMC) from 48 patients with AE and 35 control subjects was evaluated by incorporation of 3H-methylthymidine into DNA. A sequential measurement of the proliferative response of PBMC was performed in 20 patients 2 years later, and again in five of them 4 years after the first determination. After stimulation by PHA, the mean proliferation index (PI) of the patients with AE was somewhat higher than that observed in the uninfected controls, but the difference was not significant. The PI obtained with E. multilocularis antigens was higher than the threshold value in all the patients but one, and in five control subjects. The difference between the PI values in the patients with AE and those obtained in the control subjects was highly significant. There was no correlation between the lymphocyte proliferation indices and the specific antibodies assessed using the Em 2-ELISA, or the volume of the parasitic lesions. All the five 'positive' control subjects were living in areas endemic for AE. A previous contract of these subjects with E. multilocularis in the past, followed by a spontaneous elimination of the parasite is possible. The long-term persistence of lymphocyte reactivity to parasite antigens was emphasized by the results of the follow-up of 20 patients with AE: reactivity of PBMC decreased progressively but persisted more than 4 years after complete resection of the parasitic lesions in the patients who underwent a radical surgical procedure. Conversely, an increase in the PI was shown to be usually associated with a progression of the liver lesions.

Adult↗
PubMed1998

Detection of Echinococcus multilocularis in the definitive host: coprodiagnosis by PCR as an alternative to necropsy.

Recently, extensions of the range of Echinococcus multilocularis in Europe and North America and drastic increases in fox populations in Europe put an increasing proportion of the human population at risk of alveolar echinococcosis. To obtain data on the local infection pressure, studies of the prevalence of the parasite in the animals that transmit the parasite, foxes, dogs, and cats, are urgently required. Such investigations, however, have been hampered by the need for necropsy of the host animal to specifically diagnose infection with the parasite. In this study, a nested PCR and an improved method for DNA extraction were developed to allow the sensitive and specific diagnosis of E. multilocularis infections directly from diluted fecal samples from foxes. The target sequence for amplification is part of the E. multilocularis mitochondrial 12S rRNA gene. The specificity of the method was 100% when it was tested against 18 isolates (metacestodes and adult worms) of 11 cestode species, including E. granulosus. The sensitivity of the method was evaluated by adding egg suspensions and individual eggs to samples of diluted feces from uninfected foxes. The presence of one egg was sufficient to give a specific signal. To confirm the PCR results, an internal probe which hybridized only with E. multilocularis amplification products but not with the DNA of other cestodes was constructed. In order to investigate the applicability of this method for epidemiological studies, 250 wild foxes from a area in southern Germany where echinococcosis is highly endemic were examined by both necropsy and PCR of rectal contents. The sensitivity correlated with the parasites' number and stage of maturity. It ranged from 100% (>1,000 gravid worms) to 70% (<10 nongravid worms). On the basis of positive PCR results for 165 foxes, the sensitivity of the traditional and widely used necropsy method was found to be not higher than 76%. We therefore present this PCR system as an alternative method for the routine diagnosis of E. multilocularis in carnivores.

Animals↗
PubMed2001

Echinococcus multilocularis in European wolves (Canis lupus).

Nested PCR was used as a diagnostic tool to investigate the presence of Echinococcus multilocularis tapeworm in protected species of carnivores in Slovakia. Twenty-three faecal samples from wolves, four samples from bears and three samples from lynx from the Muránska Planina mountains and eight samples from wolves from the Bukovské Vrchy mountains were examined. E. multilocularis DNA was detected in two samples of wolves' faeces from the Muránska Planina mountains and one sample from the Bukovské Vrchy mountains. Examination of bears' and lynx faecal samples gave negative results. The detection of E. multilocularis in wolves has extended the range of its known definitive hosts in Europe.

Animals↗
PubMed2000

mRNA trans-splicing in the human parasitic cestode Echinococcus multilocularis.

An identical 36-nucleotide exon was identified at the 5' termini of different mRNAs from the cestode Echinococcus multilocularis. We provide evidence that this exon constitutes a new spliced leader (SL) that is obviously trans-spliced to echinococcal pre-mRNAs, donated by a non-polyadenylated, trimethylguanosine-capped SL-RNA of 104 nucleotides. Sequence comparisons indicated that cestode and trematode SLs are likely to be derived from a common ancestor gene. No conservation was, however, observed concerning the spectrum of mRNAs that is trans-spliced in cestodes and trematodes, indicating that trans-splicing of a particular flatworm mRNA is not correlated with the function of the encoded protein. We also show that the echinococcal gene elp, encoding a member of the ezrin/radixin/moesin protein family, is expressed via two alternative transcripts, spliced either cis or trans at an identical splice acceptor site. This was accompanied by the formation of different elp primary transcripts, harboring a complete or a truncated upstream intron, which supports the hypothesis that alternative cis/trans-splicing depends on the presence or absence of an upstream splice donor site. A putative SL gene was also identified on chromosomal DNA of Echinococcus granulosus, indicating widespread utilization of trans-splicing in the genus.

Alternative Splicing↗
PubMed1993

Lymphocyte engraftment conveys immunity and alters parasite development in scid mice infected with Echinococcus multilocularis.

Severe combined immune-deficient (scid) mice, which lack functional B- and T-lymphocytes, were infected with Echinococcus multilocularis larval tissue before or after reconstitution with lymphoid cells from immunocompetent donor mice. Untreated scid mice were highly susceptible to E. multilocularis infection, while scid mice reconstituted with purified lymphocytes derived from either infected or uninfected normal donor mice were capable of almost totally suppressing the growth of the larval cyst mass. The somatic development of the larval parasite varied according to the infection status of the cell donor, with protoscolices forming in scid mice reconstituted with cells from uninfected normal mice but not in those receiving cells from infected normal mice. These results confirm earlier findings that lymphocytes are important in suppressing the growth of E. multilocularis cysts in the intermediate host and also indicate that protoscolex development is influenced by lymphocytes or their products.

Animals↗
PubMed1996

Antibody responses against Echinococcus multilocularis antigens in naturally infected Rattus norvegicus.

Two Norway rats, Rattus norvegicus, were found to be naturally infected with Echinococcus multilocularis in Japan. One of them was simultaneously infected with at least three different sized metacestodes of Taenia taeniaeformis. These two R. norvegicus rats and another R. norvegicus naturally infected with T. taeniaeformis and Capillaria hepatica were examined to see if they showed any antibody responses against these two cestode parasites with the view to obtaining more information on the importance of rats as the intermediate host for E. multilocularis. These R. norvegicus showed very poor antibody responses against the two cestode species, although the Wistar rats, R. rattus, experimentally infected with a single smaller sized metacestode of T. taeniaeformis showed stronger responses not only against T. taeniaeformis but also against E. multilocularis. Therefore the three R. norvegicus naturally infected with E. multilocularis and/or T. taeniaeformis demonstrated virtually no immune response, at least against these cestodes.

Animals↗
PubMed2001

Choropleth mapping of regional count data of Echinococcus multilocularis among red foxes in Lower Saxony, Germany.

In this paper, choropleth maps display the geographical distribution of Echinococcus multilocularis in red foxes in Lower Saxony. Areas of high prevalence of the infection in foxes and with high fox population density pose high risk for the human population for alveolar echinococcosis. Spatial statistical methods were used to analyse regional count data obtained from 5365 hunted or found-dead foxes. Spatial smoothing (of raw estimates of regional prevalences based on count data before mapping) was used because raw estimates can give an erratic impression of the spatial pattern of the infection. For smoothing, empirical Bayesian methods are used as an explorative spatial epidemiological tool. The resulting map showed the geographical variation of the estimated prevalences around a median at 9% and indicated the presence of spatial-trend effects. Based on this finding, conditional autoregressive spatial modelling for Freeman-Tukey transformed data was used as an inferential spatial epidemiological tool. There were significant additive linear and quadratic spatial-trend effects with elevated prevalences in the north and south and extreme values (prevalences>38%) for the south of Lower Saxony.

Animals↗
PubMed1999

Coproantigen survey for Echinococcus multilocularis prevalence of red foxes in Hokkaido, Japan.

An epidemiological survey was conducted on the seasonal variation of Echinococcus multilocularis prevalence in red foxes from 1997 to 1998, using a monoclonal antibody-based detection of the tapeworm coproantigen. Thirty-six breeding dens of reproductive fox families were identified in the endemic area of Koshimizu, eastern Hokkaido, Japan. Fecal samples from each site were examined by coproantigen detection assay and fecal egg examination. Whereas the prevalence of coproantigen positive feces showed no seasonal fluctuation (51.6-66.7%), variation was found in the prevalence of egg positive feces in which a higher prevalence was observed in the summer and winter (31.1 and 38.7%) than spring and autumn (13.3 and 13.5%). Significant differences were observed between juveniles and adult foxes in both examinations. Samples from juvenile foxes gave higher coproantigen positive results and taeniid egg intensity. Those results suggest more juveniles infected with the cestode than adults in the same period. The practical use of coproantigen assay as a survey tool and factors which affect the prevalence and host age-related difference are discussed.

Animals↗
PubMed1997

Histochemical observations of alkaline phosphatase activity of Echinococcus multilocularis during in vivo development in golden hamsters, an alternative definitive host.

Histochemical observations of alkaline phosphatase activity of Echinococcus multilocularis during the in vivo development in golden hamster, an alternative definitive host. The present work reports on the ability of protoscoleces from a European fox strain of E. multilocularis to differentiate and develop into the adult form in the small intestine of male golden hamsters treated with prednisolone. Detection of alkaline phosphatase activity on various stages of the developing worm was performed by histochemical methods. The enzyme activity was not demonstrable in the early stages of infection but occurred with strobilization. Age-related changes in the distribution of the enzyme activity took place during strobilization. Alkaline phosphatase activity was evident in the excretory ducts of 8 to 11 day old strobila and in the tegument of mature proglottis of 16 day old worms. This in vivo procedure with rodents as definitive hosts provides interesting preliminary results on the biology of the E. multilocularis adult. Further investigations on membrane-bound enzymes involved in physiological and nutritional processes are in progress.

Alkaline Phosphatase↗