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PubMed1994

Ultrastructure of oncosphere and early stages of metacestode development of Echinococcus granulosus.

The ultrastructure of the oncospheres and developing metacestodes in vitro of Echinococcus granulosus was studied with emphasis on the origin of the laminated layer. The activated oncospheres measured 28 microns (S.D. = 1.83), and by day 5 of in vitro culture the metacestodes attained diameters up to 52 microns (S.D. = 2.66). The oncospheral plasma membrane of the tegument appeared to be formed by a microtubular cytoskeleton arranged in a predetermined pattern. By day 2 there were three main types of vesicles in the perikaryon: Vd, Vg1 and Vg2. Vesicles appeared to be synthesized in the perikaryon and continuously transported to the periphery, where the Vd vesicles could contribute to the ground substance of the syncytial tegument. We suggest that the Vg1 and Vg2 vesicles contribute to the laminated layer where, by day 5, they were seen in increased density and forming aggregations on the outer border.

Animals↗
PubMed1996

Presence of Echinococcus oligarthrus (Diesing, 1863) Lühe, 1910 in Lynx rufus texensis Allen, 1895 from San Fernando, Tamaulipas state, in north-east Mexico.

A bobcat was found recently killed on "Highway 101" near the town of San Fernando, Tamaulipas State, Mexico (100 km south of Brownsville, TX, U.S.A.). The cat (Lynx rufus texensis) was parasitized by several species of nematodes and trematodes, but mainly by a cestode, Echinococcus oligarthrus. The diagnostic characteristics of this cestode are described and illustrated. E. oligarthrus has not been reported previously in North America. This is the first time that the strobilar stage has been recovered from a "bobcat". A potential public health problem may be raised by the presence of this cestode in Mexico.

Animals↗
PubMed1985

The immune response to Echinococcus granulosus: sequential histological observations of lymphoreticular and connective tissues during early murine infection.

This paper describes the organ weight changes and the early (0 to 56 days) histological and ultrastructural changes in the lymphoid structures and injection sites after subcutaneous infection of Balb/c mice with Echinococcus granulosus protoscolices (psc). Local lymph nodes enlarged markedly, reaching maximal weight 5 to 14 days after infection (pi). Expansion of the thymus-dependent areas of draining lymph nodes was first recognized at 3 days pi and reached a maximum between 14 and 21 days pi. Lymphoproliferation within B-cell-dependent areas was less extensive and of shorter duration. Comparable, but diminished, changes were seen in contralateral lymph nodes and spleen. Lymphoid cell depletion was observed in T-dependent areas of lymphoid organs by 56 days pi. Local inflammatory reactions to psc, at the site of injection, were intense, involving neutrophils, eosinophils, macrophages and mast cells. Viable psc were present until at least 6 weeks pi. The central role of the T-lymphocyte in recognition of, and response, to E. granulosus psc is discussed.

Animals↗
PubMed1990

Use of a monoclonal antibody specific for a protein epitope of Echinococcus granulosus antigen 5 in a competitive antibody radioimmunoassay for diagnosis of hydatid disease.

A monoclonal antibody (mAb) designated as EG 02 154/12, specific for the major antigen (antigen 5) of Echinococcus granulosus was produced, and used to study the binding sites recognized by anti-antigen 5 antibodies from patients with hydatid disease. The nature of the target epitope was partially characterized. The antibody reactivity was analyzed towards sheep hydatid fluid antigens (SHF Ag) using ELISA, immunoelectrophoresis (IEP), Western blotting (WB), and immunoprecipitation (IP). In IEP, EG 02 154/12 mAb gave a single precipitin of Ag 5. The mAb and human hydatid patient sera recognized a major antigen of 64 kDa, in SHF Ag analyzed in non-reducing conditions. Both types of antibodies revealed two components of 37 and 22 kDa in reducing conditions. Deglycosylation and delipidation of SHF Ag did not affect the mAb binding. These results, together with the observation of mAb binding to in vitro translation products from protoscoleces messenger RNA, suggest the protein nature of the epitope recognized on the antigen 5. Using competitive antibody radioimmunoassay (CRIA), a competition between this mAb and hydatid patient sera, for the same epitope or closely related sites on antigen 5, was observed. No such competition was detected with the sera from other helminthiasis. The sensitivity and specificity of CRIA was compared to that of ELISA and CRIA found to be an improved diagnostic test for hydatid disease.

Animals↗
PubMed1991

In vitro and in vivo efficacy of epsiprantel against Echinococcus granulosus.

In vitro, epsiprantel at a concentration of 10 micrograms ml-1 caused tegumental damage and death of protoscoleces, juveniles (seven-day-old) and adult (37-day-old) Echinococcus granulosus. Degenerative changes and death occurred more rapidly in the older parasites. Similarly, epsiprantel was more effective against adult (28-day-old) than seven-day-old experimental infections of E granulosus in dogs. Oral doses of 2.5, 5 and 7.5 mg kg-1 were greater than 96 per cent, 99.9 per cent and 99.99 per cent active, respectively, against mature worms, whereas in seven-day-old infections doses of 5, 7.5 and 10 mg kg-1 produced greater than 94 per cent, 90 per cent and 99.8 per cent reduction in worm burdens, respectively. No side effects from treatment were seen.

Administration, Oral↗
PubMed1991

Echinococcus granulosus: antigenic proteins in oncospheres and on the surface of protoscoleces identified by serum antibodies from infected dogs.

Proteins present in oncospheres and on the surface of living protoscoleces of Echinococcus granulosus were radioiodinated by the lodogen technique and immunoprecipitated with sera from dogs with E granulosus infection and several categories of control sera. Analysis of immunoprecipitates was performed using sodium dodecyl-sulphate polyacrylamide gel electrophoresis to identify antigenic protein components specific for E granulosus. Sera from dogs with E granulosus infection identified antigenic proteins of around Mr 37,000, 30,000 or 22,000 in oncospheres, and proteins of around Mr 70,000, 43,000, 36,000, 27,000 (triplet), 20,000 or 14,000 on the surface of protoscoleces. These antigens appear to be both species- and stage-specific and may be useful for serological discrimination between 'current' and 'recent past' prepatent and patent E granulosus infections in dogs.

Animals↗
PubMed1992

Comparative immunoelectrophoretic analysis of Echinococcus granulosus, Taenia hydatigena and Taenia pisiformis cyst fluid antigens by hyperimmune rabbit sera.

Cyst fluid antigens of Echinococcus granulosus, Taenia hydatigena and T pisiformis were examined by electrophoresis using homologous and heterologous hyperimmune rabbit sera to these antigens. While arc 5 forming antibodies were identified in sera from rabbits immunised with E granulosus and T hydatigena cyst fluids, antibodies responsible for forming precipitating antigen B band were detected in rabbit antisera to E granulosus, T hydatigena and T pisiformis antigens. T hydatigena cyst fluid appears to contain antigen similar to E granulosus antigen 5 and probably antigen B while T pisiformis cyst fluid has mainly an antigen close to hydatid antigen B.

Animals↗
PubMed1977

Strain differences in Echinococcus granulosus, with special reference to the status of equine hydatidosis in the United Kingdom.

The genetics of speciation in the genus Echinococcus are briefly discussed. As the organism is a hermaphrodite and multiplies asexually in the larval stage, the genetic mechanism for the ready production of new strains is inherent in the life-cycle. Some biological, biochemical and nutritional differences between the horse and sheep strains are examined. The sheep strain may be grown to sexual maturity, in vitro, in a diphasic system; the horse strain fails to grow in such a system. Differences have also been demonstrated between the soluble proteins of the two strains. The sheep strain is infective to man but, probably, non-infective to horses. The horse strain (which is now the major strain in the U.K and Ireland) appears to be poorly infective to sheep and may prove to be non-infective to man. The importance of determining the basic characteristics of other strains of E. granulosus are also stressed.

Animals↗
PubMed1978

Echinococcus multilocoularis infection in India: First case report proved at autopsy.

The occurrence of Echinococcus multilocularis is reported in India for the first time. The patient was a young man, various clinical diagnoses were made and he finally died after an attempted membranotomy for suspected membranous obstruction in the inferior vena cava. Autopsy revealed classical E. multilocularis infection of the liver with direct spread of the inferior vena cava, the right atrium and through the diaphragm into the base of the left lung. It also had caused an outflow tract obstruction to the hepatic venous flow by direct physical pressure distorting the proximal intrahepatic portion of the inferior vena cava. In addition the patient had multi-valvular lesions of rheumatic origin and a terminal infective endocarditis due to staphyloccal infection.

Adult↗
PubMed1978

Detection of antibodies against Echinococcus granulosus arc 5 antigens by double diffusion test.

This report deals with an evaluation of a double diffusion (DD5) test which employs a control antiserum against Echinococcus granulosus arc 5 antigens to recognize arc 5-positive sera by a reaction of identity. The DD5 test was more sensitive than the immuno-electrophoresis (IEP5) test based on the same positivity criterion and was equally specific for the immunodiagnosis of human hydatidosis. Its greater simplicity suggest its application as a substitute for the IEP5 test in diagnosis, particularly areas. The application of both DD5 and latex agglutination tests is recommended for hydatid immunodiagnosis on the basis of the present findings.

Antibodies↗
PubMed1979

Isoelectric focusing of some enzymes from Echinococcus granulosus (horse and sheep strains) and E. multilocularis.

Extracts of the horse and sheep strains of Echinococcus granulosus and E. multilocularis were compared on the basis of their isoenzyme patterns for 10 enzymes by means of isoelectric focusing in polyacrylamide gels. The enzymes examined were: acid phosphatase, lactate dehydrogenase, malate dehydrogenase, malic enzyme, phosphoglucoseisomerase, isocitrate dehydrogenase, adenylate kinase, aldolase and alpha-glycerophosphate dehydrogenase. Interspecific and intraspecific differences are apparent in the isoenzyme profiles of all the enzymes except adenylate kinase; the pattern and activity of adenylate kinase are identical for both strains of E. granulosus but this enzyme clearly distinguishes these forms from E. multilocularis. The absence of electromorphic variation in any of the enzymes from either form of E. granulosus may be a result of the self-fertilizing hermaphraditism of these organisms.

Adenylate Kinase↗
PubMed1985

Strain identification of Echinococcus granulosus in determining origin of infection in a case of human hydatid disease in Australia.

Viable parasitic material from cysts removed surgically from a human patient was used to differentiate the infecting strain of Echinococcus granulosus from another to which the patient may have been exposed. It was shown that the patient was infected with the Australian mainland domestic strain. The age of the cyst material was estimated by microscopical and histological examinations. Combination of these data with an investigation of the patient's life-history allowed identification of the most likely source of infection. Studies such as this help to define those areas of high risk for human hydatidosis on mainland Australia.

Australia↗
PubMed1987

A comparison of the effects of albendazole, its sulphone metabolite, and mebendazole on the viability of protoscoleces of Echinococcus granulosus in an in vitro culture system.

The effects of albendazole, its sulphone metabolite and mebendazole on the viability of Echinococcus granulosus protoscoleces in vitro were investigated. Significant reductions in viability occurred in cultures treated with albendazole parent compound at 100 micrograms/litre, but lower concentrations were ineffective. The sulphone metabolite of albendazole had no significant effect at concentrations of 50 and 100 micrograms/litre over periods of up to 71 days. Mebendazole induced significant reductions in viability at 100 micrograms/litre.

Albendazole↗
PubMed1987

Determination of minimum effective concentration of praziquantel in in vitro cultures of protoscoleces of Echinococcus granulosus.

The minimum effective concentration of praziquantel against protoscoleces of Echinococcus granulosus (ovine strain) was determined in vitro; 20 micrograms/litre gave statistically significant results. No difference was seen between the sensitivity of ovine and equine protoscoleces at 50 micrograms/litre. Morphological observations on treated protocsoleces and passage into gerbils both suggested that the eosin-exclusion technique overestimates viability. Electron microscopy of treated protoscoleces showed severe, disruptive tegumentary damage. Praziquantel is thus an extremely active protoscolicidal agent that may have an important peri-operative role in preventing recurrence.

Animals↗
PubMed1987

In vivo efficacy of mebendazole in containment of larval cyst mass in early stages of hydatid disease due to Echinococcus granulosus.

The role of mebendazole in treatment of hydatid disease was investigated in a mouse model of human Echinococcus granulosus infection. Each animal received 2000 protoscoleces by intraperitoneal injection. Mebendazole, 50 mg/kg or 200 mg/kg body weight daily for 21 d, was given to 3 groups of animals 2, 4 and 6 months after infection. Significant decreases in numbers of cysts were seen in groups given the drug 2 and 4 months after infection, compared to the group given drug 6 months after infection. 200 mg/kg body weight was more effective in decreasing cyst numbers than 50 mg/kg.

Animals↗
PubMed1988

Echinococcus multilocularis: in vivo results of therapy with albendazole and praziquantel.

The effects of albendazole and praziquantel on the growth of Echinococcus multilocularis were studied in cotton rats. Albendazole (20 and 50 mg/kg) reduced parasite weight and increased the length of survival of infected animals but viable infection was present after treatment. In an in vitro system albendazole sulphoxide entered cysts of E. multilocularis passively. Praziquantel 100 mg/kg was ineffective but 500 mg/kg significantly inhibited growth. A combination of albendazole and praziquantel was no more effective than either agent alone.

Albendazole↗
PubMedDate not supplied

Echinococcus granulosus: in vitro maintenance of whole cysts and the assessment of the effects of albendazole sulphoxide and praziquantel on the germinal layer.

Small entire cysts of Echinococcus granulosus of human and animal origin were cultured in vitro in the presence or absence of albendazole sulphoxide (1000 micrograms/litre) or praziquantel (500 micrograms/litre) for 10 or 11 d, and subsequently passaged into the peritoneal cavity of gerbils to assess viability by continued cyst growth. Viability was reduced in the presence of albendazole sulphoxide, and disintegration of the germinal layer immediately after culture was demonstrated at the ultrastructural level. Praziquantel had no apparent effect on cyst growth.

Albendazole↗