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PubMed1978

Differences in the chemical composition and carbohydrate metabolism of Echinococcus granulosus (horse and sheep strains) and E. multilocularis.

Metabolic studies in vitro and studies on chemical composition indicate basic biochemical differences between the horse and sheep strains of Echinococcus granulosus and between these and the closely related species, E. multilocularis. The horse strain of E. granulosus has a similar level of DNA, but significantly more polysaccharides and lipids, with less RNA and protein than the sheep strain. E. multilocularis has significantly more lipids and DNA but less polysaccharides than the horse and sheep strains of E. granulosus, more RNA and protein than the horse strain but similar protein to and less RNA than the sheep strain. Incubations under air and under 95% N2-5% CO2 for 3 h show that only E. multilocularis takes up glucose, that all three forms consume different amounts of oxygen and endogenous glycogen and produce different concentrations of lactate, succinate, acetate, malate, pyruvate, propionate and ethanol as end products of carbohydrate metabolism.

Acetates↗

PubMed1978

Ultrastructural immunocytochemical localization of two hydatid fluid antigens (antigen 5 and antigen B) in the brood capsules and protoscoleces of ovine and equine Echinococcus granulosus and E. multilocularis.

The unlabelled antibody method was used in the ultrastructural localization of two hydatid fluid antigens, antigen 5 and antigen B, in brood capsules and protoscoleces of Echinococcus granulosus and E. multilocularis. Antigen 5 was found in the parenchyma cells of the protoscolex and brood capsule wall and to a lesser extent in the walls of the flame cells and collecting ducts of the excretory system and in the surrounding interstitial material. It is suggested that, while some excretion of this antigen may occur from the protoscolex, it could also be liberated into the cystic cavity by degeneration of protoscoleces and parenchymal cells of the brood capsule wall. Antigen B was found mainly in the distal cytoplasm and perinuclear cytoplasm of the tegument anterior to the suckers. It is apparently secreted to the outside and was present in the brood capsule contents; it adheres to the anterior surface and the posterior periodic acid-Schiff (PAS)-positive glycocalyx of the protoscolex and to the inner surface of the brood capsule wall. The protoscolex tegument posterior to the suckers was negative. The parenchyma cells of the protoscolex and brood capsule wall were also positive although the intensity of the reaction product was variable.

Animals↗

PubMed1975

[Echinococcus multilocularis causing extensive biliary obstruction (author's transl)].

Infection of man by Echinococcus multilocularis occurs relatively seldom, most commonly localizing in the liver in the manner of a malignant tumour. A case of alveolar hydatid disease is reported presenting with extensive biliary obstruction, and a large cavitation in the liver due to necrosis. A review of epidemiology, clinical and roentgenological findings is given.

Celiac Artery↗

PubMed1979

Protection of cotton rats against experimental Echinococcus multilocularis infections with BCG cell walls.

Previous works has indicated that cotton rats treated with Mycobacterium bovis strain BCG are effectively protected against an infection with the metastatically proliferating metacestodes of Echinococcus multilocularis. In an attempt to induce a similar protection in the absence of tubercular granulomatous lesions, cotton rats were treated with BCG cell walls. A single injection of 150 micrograms of cell walls, emulsified in mineral oil-Tween-saline, 2 weeks before the inoculation of the parasite completely protected the animals against infection with E. multilocularis. This protection was correlated with an increase in the numbers of monocytes and, as judged by acid phosphatase activity, an activation of these cells. This study shows that BCG cell walls are as effective in protecting animals against E. multilocularis as the viable organism.

Animals↗

PubMed1978

Discrimination of the larval stages of Echinococcus oligarthrus (Diesing, 1863) and E. vogeli Rausch and Bernstein, 1972 (Cestoda: Taeniidae).

Rostellar hooks of protoscolices from known larval stages of Echinococcus oligarthrus (Diesing, 1863) and E. vogeli Rausch and Bernstein, 1972 were compared to determine whether morphologic differences could be defined. The large and small hooks, respectively, of the two species were found to differ significantly in length (P = less than 0.0001) as well as in relative proportions. Host-related variation in lengths of hooks was not observed. Dimensions of the rostellar hooks were found to provide means for the discrimination of the larval stages of E. oligarthrus and E. vogeli, of which the latter is the cause of polycystic hydatid disease in man in South and Central America. The defined criteria were used in the identification of larvae from wild rodents and man.

Echinococcus↗

PubMed1979

Echinococcus vogeli in man, with a review of polycystic hydatid disease in Colombia and neighboring countries.

Three cases of polycystic hydatid disease (PHD) from Colombia are reported and 11 others from the region are reviewed. When cysts from two patients were fed to a dog and an ocelot about 250 mature and gravid specimens of Echinococcus vogeli and two poorly developed strobilae, respectively, were recovered. These human cases constitute the first record of the larval stage of E. vogeli, previously known only from the strobilar stage in the type host, the bush dog (Speothos venaticus). Based on the morphological characteristics of the protoscolex rostellar hooks from other PHD cases (6 Colombian, 1 Ecuadorian, and 1 Panamanian), it was concluded that all were also due to E. vogeli, rather than to E. oligarthrus as had been previously suggested. Although E. oligarthrus is or may be present in the same areas, so far no human infection due to this parasite has been confirmed. Of the 14 cases reported, 13 were pathologically proven to be PHD. Clinically, eight had an undiagnosed tumor-like mass in or near the liver, one had a subcutaneous mass in the anterior sixth intercostal space, and in two the cysts were in the chest. Two were autopsy findings. In contrast to E. multilocularis, the cysts produced by E. vogeli were found to be relatively large and filled with fluid; brood capsules and protoscolices were numerous. Focal necrosis was commonly observed but large necrotic cavities were not seen. The main natural intermediate host is the paca (Cuniculus paca); man probably obtains the infection by contamination from feces of infected hunting dogs.

Adolescent↗

PubMed1979

Echinococcus granulosus and E. multilocularis: in vitro culture of the strobilar stages from protoscoleces.

The techniques for the in vitro culture of Echinococcus granulosus and E. multilocularis are described in detail. The sheep strain of E. granulosus was grown to sexual maturity but fertile eggs were not produced due to the failure to achieve insemination in vitro. The horse strain of E. granulosus grew only slightly in vitro and then ceases to develop, although remaining active for long periods. E. multiloculoris differentiated largely into unsegmented, sexually mature, "monozoic" forms; some organisms developed "pseudo-proglottids" with the interproglottid membrane absent or poorly formed. After prolonged culture, some strobila of E. multilocularis developed an extra scolex.

Animals↗

PubMed1979

Cross-protection between the cysts of Echinococcus granulosus, Taenia hydatigena and T ovis in lambs.

Lambs were infected orally at 14 weeks of age with either Taenia hydatigena, T ovis or Echinococcus granulosus eggs. To induce high levels of resistance to oral reinfection, they were then injected intramuscularly with eggs of the homologous species four weeks and eight weeks later. The degree of immunity was then tested by oral challenge with eggs from either the homologous or an heterologous species. Autopsy results indicated that prior infection with an homologous species induced a very high degree of immunity to challenge infection. Prior infection with all combinations of heterologous species resulted in a lesser degree of immunity, which appeared to have acted on the establishment phase of development and did not influence cyst survival.

Animals↗

PubMed1979

[Echinococcus multilocularis: superinfections in experimentally infected mice (author's transl)].

The influence of subcutaneous superinfections following an intraperitoneal primary infection after 4 and 14 weeks respectively has been examined in Echinococcus multiolcularis infected NMRI-mice. It could be shown that the growth of subcutaneous echinococci is inhibited in superinfected mice (372 mg) if compared with control mice (903 mg parasite weight). Other differences (composition of serum proteins and white blood cells, hemoglobin content) are exclusively due to the primary intraperitoneal infection.

Animals↗

PubMedDate not supplied

Characterization of allergens in Schistosoma mansoni, Fasciola hepatica and Echinococcus granulosus.

Various antigens interacting specifically with IgE antibodies from infected humans were identified in S. mansoni, F. hepatica and E. granulosus soluble extracts by means of radioimmunoelectrophoresis. Two allergens common to adult worm and cercariae were identified in S. mansoni extracts. They proved to be distinct from genus--or species--specific antigens previously identified in the parasite. In adult F. hepatica extract a species-specific antigen and another lipoprotein were shown to interact with IgE antibodies of patients with fasciolasis. Two major allergens were also found in whole fluid of sheep E. granulosus cysts. One of them corresponded to Echinococcus genus specific antigen. These results are discussed according to immunological findings in parasitic infections.

Allergens↗

PubMed1978

Survival of protoscolices of Echinococcus granulosus at constant temperatures.

A study was conducted to determine the effects of storage at constant temperatures upon the survival of protoscolices of Echinococcus granulosus from hydatid cysts removed from infected sheep. Parallel tests were conducted on intact cysts from both lung and liver, and on protoscolices stored within 1-ml samples of hydatid fluid. The longest survival times of any of the samples tested at each temperature were: -20 C, 1 hr; -10 C, 4 hr; 1 C, 16 days; 10 C, 16 days; 20 C, 8 days; 30 C, 4 days; 40 C, 2 days, and 50 C, 2 hr. In general, protoscolices survived considerably better when stored within intact cysts than when in 1 ml of hydatid fluid. At temperature ranges where putrefaction occurred, protoscolices in cysts from lung survived longer than those from liver. The ability of these protoscolices to survive extended periods of time after an infected sheep has died or been killed suggests that stringent preventive and control measures should be established in areas where hydatid disease is endemic. Animal pits at community dumping grounds where sheep carcasses might be discarded should be enclosed or covered, and all stray and roving dogs in those regions should be rigidly controlled.

Animals↗

PubMed1977

Permeability studies on taenid metacestodes: I. Uptake of proteins by larval stages of Taenia taeniaeformis, T. crassiceps, and Echinococcus granulosus.

Host immunoglobulins of several different classes were detected within the bladder fluids of Taenia taeniaeformis, T. crassiceps, and Echinococcus granulosus. Radioiodinated proteins were taken up in vitro by larvae of both T. taeniaeformis and T. crassiceps and were shown to retain their physicochemical and antigenic characteristics. Rates of uptake were similar in the 2 species and were not related to the molecular weight of the proteins. Immunoglobulins were taken up both in vitro and in vivo by larvae of T. taeniaeformis. Absorbed immunoglobulins were shown to retain both antigen binding capacity and biologic functions associated with the Fc portion of the molecules. Not all cysts of E. granulosus contained detectable host proteins. Uptake of 125I occurred when hydatid cysts were exposed to labeled proteins in vitro, but it appeared that rapid degradation of the labeled carrier led to the appearance of dialysable fragments. This may be attributable to proteolysis within the bladder fluid. We conclude that taeniid metacestodes are capable of absorbing a variety of proteins, and that these macromolecules can retain their structural and functional integrity following transport. This absorptive capacity accounts for the presence of host serum components within bladder fluids.

Animals↗

PubMed1977

Further observations on the specificity of antigen 5 of Echinococcus granulosus.

The presence of IgE antibodies to antigen 5 of Echinococcus granulosus was detected by means of radioimmunoelectrophoresis in the sera of two of six patients infected with E. multilocularis. Sera from three of these patients gave a precipitin band in gel diffusion tests identical to that produced by a monospecific rabbit anti-E. granulosus antigen 5 serum, when tested against whole hydatid fluid. Sera from 19 individuals infected with Fasciola hepatica, 20 with Schistosoma mansoni, and 5 with with Taenia saginata showed no detectable antibodies against antigen 5 of E. granulosus, The monospecific rabbit anti-E. granulosus antigen 5 serum did not react in immunodiffusion with homologous antigen when absorbed with either 4 mg/ml of whole hydatid fluid or with 200 mg/ml of a soluble E. multilocularis extract. Absorption of the monospecific antiserum with crude antigens of either F. hepatica, Onchocerca volvulus, S. mansoni, or T. saginata did not abolish the reaction with antigen 5. It appears, therefore, that antigen 5 can no longer be considered specific for E. granulosus, but is also present in E. multilocularis. In the light of this observation, some reevaluation of immunodiagnostic tests in hydatid disease will be necessary.

Antibody Formation↗

PubMed1978

[Fenbendazole therapy of experimental larval echinococcosis. I. The effect of fenbendazole on worm burden and protoscolex development of Echinococcus multilocularis (author's transl)].

Application of fenbendazole (methyl-5-(phenyl-thio)-benzimidazole-2-carbamate) in Echinococcus multilocularis infected mice showed a significant efficiency on the development of the cysts; the worm burden and the number of protoscolices were significantly reduced in the treated animals in comparison with the non-treated control mice. The degree of efficiency was subject to the way of application, the duration of medication, and the parasite strain: 1. On application of f. as medicated feed (500 ppm) worm burden and protoscolex number were reduced the most an average parasite weight of 105 mg and 2 protoscolices against 1942 mg and 99 protoscolices. Treatment by oral application with emulsion of 2.5% (1 ml/mouse/day, 5 x per week over a period of 2--5.5 months) the efficiency was less expressed (845 mg, 53 protoscolices). 2. By extending the treatment from 60 to 102 and 165 days resp. the reduction of worm burden can be increased from 81 to 95%. 3. From 2 parasite strains one which was recently isolated from a fox, reacted more on the treatment than the other one: 85 mg parasite weight against 1218 mg in the nontreated controls. On the other strain continued since about 25 years by intraperitoneal inoculation, the efficiency was more reduced: The worm burden was 866 against 2666 mg in the control mice.

Animals↗

PubMed1977

Antigenic characterization of Echinococcus granulosus cysts.

Limited numbers of antigens were detected in the structural components of Echinococcus granulosus cysts by double diffusion and immunoelectrophoresis tests using homologous and heterologous antisera without antibody activity to host serum contaminants. Although antigens common to the germinal membranes, laminated layers and protoscoleces were demonstrated, no evidence was found of antigen sharing between the laminated layer and hydatid fluid from fertile and sterile cysts. These fluids, however, had antigenic determinants in common with protoscoleces. Antigens responsible for the formation of a characteristic cathodic are were detected but only in the three structural cyst components. In contrast, E. granulosus arc 5 antigens were found solely in hydatid fluid. These observations suggest that these two antigen groups are of somatic and metabolic origin, respectively. The results are discussed in terms of current knowledge of the immunobiology of hydatid cysts.

Animals↗

PubMed1977

Comparative antigenic characterisation of Echinococcus granulosus and Taenia hydatigena cyst fluids by immunoelectrophoresis.

Hydatid cyst fluid from Echinococcus granulosus (HCF) and cyst fluid from Taenia hydatigena (TCF) cysts were compared in reciprocal immunoelectrophoresis (IEP) tests using homologous and heterologous antisera which were free of antibodies to host serum contaminants. The antigens for the E granulosus arc 5 were demonstrated in TCF. Antibody activity to these and other antigens common to HCF and TCF was removed from homologous antisera by absorptions with the heterologous antigenic preparation. Antigens not shared by the two metacestodes fluids were then demonstrated by IEP tests. These findings are discussed in terms of their significance to phylogenetic and immunodiagnostic studies of these parasites in their immediate hosts.

Animals↗

PubMed1977

Activation of complement by hydatid cyst fluid of Echinococcus granulosus.

Factors present in hydatid cyst fluid of Echinococcus granulosus were found to interact with complement from several species. This nonimmunologic fixation resulted in the depletion of hemolytically active complement from fresh guinea pig serum, the conversion of human C3 to an electrophoretically faster species and the genration of smooth muscle contracting substances, analogous to anaphylatoxins, in normal rat serum in vitro. Vascular permeability changes were produced in vivo in rats and humans after intradermal inoculation of complement interacting fractions of hydatid fluid. It is suggested that these factors may contribute to the pathogenesis of the shock syndrome which follows intravenous administration of hydatid fluid in normal animals, and to the nonspecificity of immunodiagnostic skin tests for hydatid infection in man and animals.

Anaphylatoxins↗

PubMed1977

Host serum proteins in Echinococcus multilocularis: complement activation via the classical pathway.

The presence of host serum proteins, including IgG and IgM, within the cyst membranes and on the surface of protoscoleces of Echinococcus multilocularis was demonstrated by the use of HRPO-conjugated purified antisera. Viable protoscoleces incubated either in EDTA- or EGTA-fresh human sera were not lysed; the addition of calcium restored the protoscolecidal activity of the EGTA serum. It is concluded that the complement-mediated lysis of this metazoan organism proceeds via the classical pathway of complement activation. The results are discussed in relation to the ability of this parasite to survive in the immunologically hostile environment of the host.

Animals↗