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PubMed1989

Cellular immune response in Echinococcus multilocularis infection in humans. II. Natural killer cell activity and cell subpopulations in the blood and in the periparasitic granuloma of patients with alveolar echinococcosis.

In animal models, the development of Echinococcus multilocularis larvae has been shown to correlate with the immune status of the host, and particularly with cellular immunity. In humans, a defect in immune regulation may explain the persistence of cellular infiltration and fibrogenesis. We assessed natural killer (NK) activity in the peripheral blood mononuclear cells (PBMC) of patients with alveolar echinococcosis, and compared in 12 patients who underwent a surgical procedure the cell populations in the PBMC with those present in the periparasitic granuloma. The results indicated that (i) the NK cell activity of the PBMC was significantly altered at the lower NK cell: target cell ratios; (ii) the percentage of CD8+ cells was significantly decreased in the PBMC with an increased CD4:CD8 cell ratio; (iii) inversely, the CD8+ cells constituted the main population of T cells in the liver of most patients; and (iv) the periparasitic granuloma was mainly composed of macrophages, T cells and myofibroblasts in close association with the developing fibrosis. A relatively high number of CD4+ cells in the periparasitic granuloma of two patients with 'abortive' parasitic lesions suggested that, as it is observed in experimental E. multilocularis infection, differential evolution of the phenotypic pattern of the periparasitic granuloma could be related to resistance or sensitivity to infection by E. multilocularis in humans.

Adult↗
PubMed1988

[Natural infestation of domestic cats (Felis catus L.) by Echinococcus multilocularis Leuckart, 1863 (Cestoda): first case in France detected in peri-urban area].

A minute specimen of a tapeworm from the small intestine of a domestic cat is related to Echinococcus multilocularis. The natural infestation of the cat by this species of cestode is demonstrated in France for the first time. The cat was captured in the field around buildings of the neighbourhood of Annemasse (Haute-Savoie). This case illustrates the possibility of an urban life cycle extension of alveolar echinococcosis in the permanent endemic areas of the zoonosis in France and also the eventual risks of contamination for urban dwellers by parasite eggs laying on the ground or on the carnivorous domestic animal furs.

Animals↗
PubMed2003

Prevalence of Echinococcus multilocularis in the red fox (Vulpes vulpes) in southern Belgium.

Between June 1998 and February 2002, 709 red foxes killed in Wallonia (south of Belgium) were available for parasitological examination of the gut. The identification of Echinococcus multilocularis was based on morphological data. E. multilocularis adults were observed in 20.2% of the animals. The analysis of data revealed marked differences between the geological areas of Wallonia; the highest prevalence (33%) was found in the Ardenne and the lowest (0%) on the Plateau de Herve. Host gender and the collection season had no effect on the prevalence. However, the latter was significantly higher in juveniles (<8 months of age). The geographical distribution of E. multilocularis in Belgium is much wider than originally thought.

Age Factors↗
PubMed1992

Parasitological and serological studies on the prevalence of Echinococcus multilocularis Leuckart, 1863 in red foxes (Vulpes vulpes Linnaeus, 1758) in Switzerland.

In the Canton of Zurich in Switzerland, 1,252 red foxes (Vulpes vulpes) were examined during 1990-1991 for intestinal stages of Echinococcus multilocularis using the mucosal smear technique. Special safety precautions were employed during examination. An average of 35% (432 foxes) were infected, mostly with low to medium numbers of gravid worms producing thick-shelled eggs. In the eleven districts of the Canton, prevalence rates varied between 13% and 57%. An average of 29% of the foxes had antibodies in serum or body fluid against a highly species-specific antigen of E. multilocularis (Em2-antigen). The fact that foxes with intestinal E. multilocularis infection have been found in all parts of the Canton of Zurich indicates a relatively high potential infection risk for humans, but apparently the risk is reduced by certain extrinsic or intrinsic factors which have yet to be determined.

Age Factors↗
PubMed2006

Climate and environmental factors influencing Echinococcus multilocularis occurrence in the Slovak Republic.

During the period of 2000-2004, 3,096 red foxes from the whole territory of the Slovak Republic were sampled and examined parasitologically for infections with Echinococcus multilocularis, causative agent of serious alveolar echinococcosis in humans. Relations between prevalence of the parasite in individual regions of Slovakia and some environmental factors were weighted. During the study period, great differences of prevalence and infection intensity were found on a regional level and significant between-year fluctuation of both parameters was observed. High-endemic foci with an estimated prevalence of more than 30 % were detected in the northern and central part of the country. Climatic conditions, including low mean annual air temperature, high mean annual rainfall and the high humidity of the soil, showed to be important for E. multilocularis distribution. Significant correlation was calculated between prevalence of the tapeworm, mean annual precipitation values, and population density of small mammals.

Animals↗
PubMed2001

Echinococcus multilocularis alkaline phosphatase as a marker for metacestode damage induced by in vitro drug treatment with albendazole sulfoxide and albendazole sulfone.

Alveolar echinococcosis (AE) is caused by the metacestode stage of the fox tapeworm Echinococcus multilocularis. The disease affects the human liver and occasionally other organs and is fatal if treatment is unsuccessful. The present chemotherapy of AE is based on the administration of benzimidazole carbamate derivatives, such as mebendazole and albendazole. Albendazole treatment has been found to be ineffective in some cases, parasitostatic rather than parasiticidal, and the recurrence rate is rather high. Therefore, chemotherapy usually involves the lifelong uptake of massive doses of albendazole and new treatment options are urgently needed. In order to avoid costly and time-consuming animal experimentation, a first step in searching for novel parasiticidal compounds could be the in vitro drug screening of novel compounds by employing metacestode cultivation. However, presently used techniques (e.g., transmission electron microscopy) for determination of parasite viability involve costly equipment and time-consuming preparation of rather large amounts of parasite material. We therefore searched for a parasite marker which can be easily traced and the presence or absence of which is indicative of parasite viability. In this study we show that the increase of E. multilocularis alkaline phosphatase activity in culture supernatants during in vitro drug treatment with albendazole derivatives correlates with the progressive degeneration and destruction of the metacestode tissue. The inexpensive and rapid assay presented here will serve as an ideal tool for performing first-round in vitro tests on the efficacy of a large number of antiparasitic compounds.

Albendazole↗
PubMed1990

A programme to reduce the risk of infection by Echinococcus multilocularis: the use of praziquantel to control the cestode in a village in the hyperendemic region of Alaska.

This paper reports the results of a 10-year field trial designed to reduce the risk of infection by Echinococcus multilocularis to residents of a village in a hyperendemic area (Savoonga, St. Lawrence Island). The objective was to prevent dispersal of infective eggs of the cestode within the village by means of monthly treatments of dogs with praziquantel. Northern voles, Microtus oeconomus, present in the village as commensals, served as an index of risk, as the incidence of infection in the voles provides information about the availability of eggs within the confines of the inhabited area. Voles were examined annually during early June before the population of overwintering voles was diluted by the first annual litters. The pretreatment infection-rate within the village was 29% (range 22-35%), and in control areas at some distance from the village for the entire study period it averaged 53% (284 infected voles from a sample of 533). Some fluctuation in incidence of infection in village voles occurred, apparently depending on the extent to which the residents kept their dogs chained and thus available for treatment. The success of the programme was demonstrated by the reduction in prevalence of infection to about 1% of voles in 1985, and an average infection rate during the last five years of the study of 5% (29 infected voles in a sample of 582). This 83% average reduction in the prevalence of the larval cestode within the village reflects a corresponding reduction in the risk of acquiring by the residents of the village. The method would be applicable for the control of E. multilocularis in most hyperendemic regions. Success depends, however, on elimination of unrestrained dogs and a precise schedule of treatment.

Alaska↗
PubMed2003

Detection of Echinococcus multilocularis antigens in faeces by ELISA.

Faecal samples deriving from 391 animals belonging to nine species (polecats, badgers, martens, weasels, rats, dogs, cats, red foxes, raccoon-dogs) were examined by capture ELISA for the presence of the Echinococcus multilocularis coproantigen. The main claim of our studies is the reliable detection of E. multilocularis coproantigens, mainly in the faeces of foxes, dogs and cats. For the first time in coproantigen detection we used a "double-sandwich" ELISA. The main advantage of this method is the higher specificity and better differentiation of positive and negative faecal samples, in comparison with sandwich ELISA. The overall specificity of double-sandwich ELISA was 95.1% with only 16 of 327 E. multilocularis-free animals giving false-positive results. The E. multilocularis coproantigen was detected by double-sandwich ELISA in 37.5% of examined red foxes and in 8.0% of examined raccoon-dogs, compared with a prevalence of just 29.8% in red foxes and 8.0% in raccoon-dogs, as determined by parasitological techniques.

Animals↗
PubMed1992

Developmental changes of Echinococcus multilocularis metacestodes revealed by tegumental ultrastructure and lectin-binding sites.

Ultrastructural investigations (SEM, TEM) combined with lectin-binding analysis, have revealed concurrent modifications in tegumentary structure and surface glycoconjugates during the establishment and differentiation of Echinococcus multilocularis metacestodes in jirds. The laminated layer, which is amorphous and rich in polysaccharides when initially secreted by the young cyst, takes on a different appearance and has a different glycoconjugate composition according to whether the cyst becomes fertile or sterile. The laminated layer of fertile cysts transforms into a microfibrillar matrix, the protein content of which may increase while sugar content decreases during protoscolex differentiation. Independently of this structure, brood capsules, from which arise protoscoleces, are formed by invagination of the cyst tegument. The intense secretion of glycoconjugates from the brood capsule wall during invagination may serve to interact with host factors passing through the laminated layer. The combined use of ultrastructural study and lectin labelling has allowed the demonstration of an ultrastructural and biochemical gradient of differentiation of the protoscolex. Seven stages of differentiation have been described. The possibility that the excreted-secreted tegumentary glycoconjugates, revealed by lectin labelling during protoscolex differentiation, might be the gradual biochemical expression of one or several stimuli implicated in the phenomenon of protoscolex maturation, is discussed.

Animals↗
PubMed2002

Effect of Echinococcus multilocularis on the origin of acetyl-coA entering the tricarboxylic acid cycle in host liver.

Carbon-13 nuclear magnetic resonance (NMR) spectroscopy was employed to investigate alterations in hepatic carbohydrate metabolism in Meriones unguiculatus infected with Echinococcus multilocularis. Following portal vein injections of an equimolar mixture of [1,2-13C2]acetate and [3-13C]lactate, perchloric acid extracts of the livers were prepared and NMR spectra obtained. Isotopomer analysis using glutamate resonances in these spectra showed that the relative contributions of endogenous and exogenous substrates to the acetyl-CoA entering the tricarboxylic acid cycle differed significantly between infected and control groups. The mole fraction of acetyl-CoA that was derived from endogenous, unlabelled sources (F(U)) was 0.50 +/- 0.10 in controls compared to 0.34 +/- 0.04 in infected animals. However, the fraction of acetyl-CoA derived from [3-13C]lactate (FLL) was larger in livers of infected animals than those from controls with values of 0.27 +/- 0.04 and 0.18 +/- 0.04, respectively. Similarly, the fraction of acetyl-CoA derived from [1,2-13C2]acetate (FLA) was larger in livers of infected animals compared to those in controls; the fractions were 0.38 +/- 0.01 and 0.32 +/- 0.07, respectively. The ratio of FLA:FLL was significantly smaller in the infected group with a value of 1.42 +/- 0.18 compared to 1.74 +/- 0.09 for the controls. These results indicate that alveolar hydatid disease has a pronounced effect on the partitioning of substrates within the pathways of carbohydrate metabolism in the host liver.

Acetyl Coenzyme A↗
PubMed1997

Echinococcus multilocularis: mouse strain difference in hydatid development.

Female mice of nine inbred strains (A, AKR, BALB/c, C3H, C57BL/6, C57BL/10, CBA, DBA/1 and DBA/2) and H-2 congenic B10.D2, at 9-10 weeks of age, were infected with larval Echinococcus multilocularis by trans-portal injection of hydatid homogenate. Parasitized livers were histologically examined 9 or 13 weeks after infection. Hydatid development was quite different among mouse strains. Multivesiculation was prominent in C57BL/10, DBA/1, C57BL/6 and BALB/c. Protoscoleces were well developed in DBA/2, AKR, DBA/1 and CBA. H-2 congenic B10.D2, which has the background genes of C57BL/10 except for the H-2d gene of DBA/2, resembled C57BL/10 in prohibiting the development of protoscoleces. These data suggest that the qualitative difference in hydatid development may be regulated by non-H-2 gene(s).

Animals↗
PubMed1992

Natural Echinococcus multilocularis infection in a Norway rat, Rattus norvegicus, in southern Hokkaido, Japan.

Forty-two rats, Rattus norvegicus, captured at a garbage dump in southern Hokkaido, Japan, were examined, and one was found to be infected with Echinococcus multilocularis. The lesions were found in the liver, lung, mesenteric lymph nodes, greater omentum and also free in the abdominal cavity. No necrosis was observed in any of the lesions, and inflammatory reactions were mild. Protoscoleces were observed in the large liver cysts. A homogenate of these cysts, when transplanted into the abdominal cavity of three Mongolian gerbils and a rat, yielded numerous fully developed protoscoleces at 4-7 months post-inoculation. Judging from this, it is postulated that the rat could become a natural intermediate host for E. multilocularis in this area.

Animals↗
PubMed1995

In vitro quantitative assessment of Echinococcus multilocularis metacestode viability after in vivo and in vitro maintenance.

The aim of this study was to apply the enzymatic MTT (3,5 dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide--formazan colorimetry for quantifying the viability of Echinococcus multilocularis whole cysts, after maintenance in vivo or in vitro. The enzymatic activities of young cysts freshly removed from rodents were linearly correlated with the parasite cyst weight. A comparative evaluation of the MTT assay and the in vitro viability assessments showed that the number of animals used for drug-screening purposes would be reduced by 35.8%. In this way, the use of different parasite samples removed from the same host is required, because of their different ages and their subsequent different abilities to reduce MTT. Cysts removed from mice exhibited higher colorimetric values than those removed from jirds. Thus, small entire cysts obtained from mice were maintained in the CMRL 1066 culture medium. Their enzymatic activities were evaluated at different times. The results indicate that, in such conditions, the optimal period of time for testing the effect of drugs against the metacestodes is limited to the 10 days following their transfer from mouse to culture flasks. The MTT assay encourages further studies to improve the viability of the whole cysts in vitro, using other standardizable culture conditions.

Animals↗
PubMed1990

Effects of ethyl N-N-benzyl-methyl-oxamate in Meriones unguiculatus infected with Echinococcus multilocularis metacestodes. Biochemical and ultrastructural observations.

Ethyl N-N-benzyl-methyl-oxamate is a N-substituted derivative of the oxamic acid, well-known as inhibitor of the lactate dehydrogenase activity. The biochemical and ultrastructural effects of this drug in Echinococcus multilocularis metacestodes and the repercussions in the livers of receptive host, Meriones unguiculatus, were investigated. This compound decreased the specific activity of the lactate dehydrogenase in the metacestodes and the host liver by 81 and 86.8%, respectively. This N-methyl compound has shown an important repercussion on the lactate dehydrogenase activity due to its greater lipophilicity and thus allows a better penetration of the molecule. In the host liver, a fall of the alkaline and acid phosphatases activity was observed. The glucose and glycogen concentrations were also decreased. The ultrastructural study provided an alteration of the tegument of the metacestodes and damages of the muscular system. The parenchyma was disorganized. In conclusion, these biochemical and ultrastructural data obtained with ethyl-N-N-benzyl-methyl oxamate in E. multilocularis metacestodes show clearly the importance of the lactate dehydrogenase activity in the metacestodes.

Acid Phosphatase↗
PubMed1999

Secondary alveolar echinococcosis in lymphotoxin-alpha and tumour necrosis factor-alpha deficient mice: exacerbation of Echinococcus multilocularis larval growth is associated with cellular changes in the periparasitic granuloma.

The availability of mice carrying a deletion of LT-alpha and tumour necrosis factor (TNF)-alpha genes enabled us to investigate the role of the TNF during alveolar echinococcosis. We compared the growth rate of Echinococcus multilocularis in LT-alphaTNF-alpha +/+ mice to that of mice having either no or only one LT-alphaTNF-alpha functionnal allele. LT-alphaTNF-alpha -/- mice harboured a significantly higher parasite burden than did the other two populations at 5, 10, and 15 weeks of infection, and they did not survive thereafter. Liver metacestodes removed from these mice were alive and the dehydrogenase activities of peritoneal metacestodes were decreased. Liver lesions regressed in most wild-type mice. Indeed, dead parasites were cordoned by granulomas containing numerous macrophages and lymphocytes leading to focal liver fibrosis at an early stage of infection. In contrast, most of LT-alphaTNF-alpha -/- mice harboured metacestodes interspersed with leucocytes, realising purulent abscesses with secondary extensive irregular fibrosis at a late stage of infection. Heterozygous mice had behavioural characteristics intermediate between homozygous mutants and wild-type mice. Levels of E. multilocularis-specific delayed-type hypersensitivity and serum antibodies were slightly decreased in LT-alphaTNF-alpha -/- mice. This study shows that TNF-alpha and/or LT-alpha genes play an essential role in the immune protection mechanisms against E. multilocularis at the site of infection.

Animals↗
PubMed1999

[Epidemiological studies on Echinococcus multilocularis in red foxes in north-west Poland].

The studies were carried out in 15 provinces of North-West part of Poland in the years 1994 - 1997 under a regime of strict laboratory safety regulation. The intestine of 1909 red foxes were examined for the presence of Echinococcus multilocularis according to the method of Eckert et al (1991). The intestines were divided finto four to six sections and fifteen smears were prepared from each animal under study. Foxes infected with E. multilocularis were detected in 8 provinces. The average prevalence rate in these provinces was 1.20 per cent. Of special interest fis the finding in Slupsk and Gdafisk regions, where 9.6 per cent of foxes were infected with E. multilocularis. In comparison with some other European endemic regions the prevalence rates of E. multilocularis in Poland was low, except for the Stupsk-Gdańsk area.

Animals↗
PubMed1998

Echinococcus multilocularis infection in mice: in vivo treatment with a low dose of IFN-gamma decreases metacestode growth and liver fibrogenesis.

As no antiparasitic drug is definitively efficient in patients with alveolar echinococcosis, the effects of exogenous IFN-gamma on murine Echinococcus multilocularis infection were assessed with regards to the parasite burden, parasite-specific immune responses, and the urinary level of the collagen cross-link pyridinolines. They were analyzed after 3-week treatments with 1 or 5 micrograms of IFN-gamma per day twice a week. The treatment with 1 microgram transiently reduced the liver metacestode load, and the metastase weight as far as 6 weeks after the end of treatment. It slightly increased Th 1-type T cell responses and reduced the excretion of pyridinolines. These results should encourage further study to assess whether the decrease in liver fibrosis leads to an improvement of the efficacy of albendazole therapy. In contrast, the treatment with 5 micrograms increased the liver metacestode load and was less efficient than that with 1 microgram in decreasing pyridinoline excretion. These results incitate to follow up carefully patients with alveolar echinococcosis who are treated with IFN-gamma.

Amino Acids↗
PubMed1998

Spatial distribution patterns of Echinococcus multilocularis (Leuckart 1863) (Cestoda: Cyclophyllidea: Taeniidae) among red foxes in an endemic focus in Brandenburg, Germany.

Over a period of 40 months, 4374 foxes were randomly sampled from an area located in northwestern Brandenburg, Germany, and examined parasitologically for infections with Echinococcus multilocularis. Spatial analysis of the origin of infected animals identified two (one central and one southeastern) high-endemic foci with an estimated prevalence of 23.8%. By contrast, a prevalence of 4.9% was found in the remaining (low-endemic) area. The prevalences among juvenile and adult foxes were compared in the high-endemic and the low-endemic areas. To analyse the central high-endemic focus further, the random sample was stratified by zones representing concentric circles with a radius of 13 km (zone 1) or x(n-1) + 7 km for the remaining three zones from the apparent centre of this focus (anchor point). Prevalences calculated for each zone showed a decrease from zone 1 (18.8%) to zone 4 (2.4%) with significant differences for all zones but zones 3 and 4. The relative risk of an infection decreased rapidly in a distance range of 26 km around the high-endemic focus, whereas the relative risk remained unchanged within a distance of 5 km around the anchor point. The importance of heterogeneous spatial distribution patterns for the diagnosis and epidemiology of the infection is discussed.

Age Distribution↗