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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↗
PubMed2004

Isolation and characterization of a secretory component of Echinococcus multilocularis metacestodes potentially involved in modulating the host-parasite interface.

Echinococcus multilocularis metacestodes are fluid-filled, vesicle-like organisms, which are characterized by continuous asexual proliferation via external budding of daughter vesicles, predominantly in the livers of infected individuals. Tumor-like growth eventually leads to the disease alveolar echinococcosis (AE). We employed the monoclonal antibody (MAb) E492/G1, previously shown to be directed against a carbohydrate-rich, immunomodulatory fraction of Echinococcus granulosus, to characterize potentially related components in E. multilocularis. Immunofluorescence studies demonstrated that MAb E492/G1-reactive epitopes were found predominantly on the laminated layer and in the periphery of developing brood capsules. The respective molecules were continuously released into the exterior medium and were also found in the parasite vesicle fluid. The MAb E492/G1-reactive fraction in E. multilocularis, named Em492 antigen, was isolated by immunoaffinity chromatography. Em492 antigen had a protein/carbohydrate ratio of 0.25, reacted with a series of lectins, and is related to the laminated layer-associated Em2(G11) antigen. The epitope recognized by MAb E492/G1 was sensitive to sodium periodate but was not affected by protease treatment. Anti-Em492 immunoglobulin G1 (IgG1) and IgG2 and, at lower levels, IgG3 were found in sera of mice suffering from experimentally induced secondary, but not primary, AE. However, with regard to cellular immunity, a suppressive effect on concanavalin A- or crude parasite extract-induced splenocyte proliferation in these mice was observed upon addition of Em492 antigen, but trypan blue exclusion tests and transmission electron microscopy failed to reveal any cytotoxic effect in Em492 antigen-treated spleen cells. This indicated that Em492 antigen could be modulating the periparasitic cellular environment during E. multilocularis infection through as yet unidentified mechanisms and could be one of the factors contributing to immunosuppressive events that occur at the host-parasite interface.

Animals↗
PubMed2004

Molecular cloning, expression, and serological evaluation of an 8-kilodalton subunit of antigen B from Echinococcus multilocularis.

Full-length cDNA and genomic DNA encoding an 8-kDa subunit of antigen B from Echinococcus multilocularis (designated EmAgB8/1) were isolated from an E. multilocularis metacestode cDNA library and a protoscolex genomic DNA library, respectively. The open reading frame of the cDNA clone encodes a polypeptide comprising 85 amino acids with a 20-amino-acid NH(2)-terminal signal sequence, which was confirmed following N-terminal sequencing of the native antigen. Reverse transcription-PCR analysis revealed that the clone encoding EmAgB8/1 is predominantly transcribed in larval E. multilocularis. The gene consists of two exons (encoding the signal sequence and mature protein) separated by a 91-bp intron. The mature form was expressed in Escherichia coli, and its antigenic reactivity was compared with that of a counterpart, an 8-kDa subunit of antigen B from Echinococcus granulosus (EgAgB8/1) by Western blotting and enzyme-linked immunosorbent assay (ELISA) with serum samples from patients confirmed to have cystic echinococcosis (CE) and alveolar echinococcosis (AE). Recombinant EmAgB8/1 showed positive reactions in Western blots with 81.3% (65 of 80) of serum samples from CE patients and 40.6% (26 of 64) of serum samples from AE patients, while recombinant EgAgB8/1 showed positive reactions with 86% (43 of 50) and 42% (19 of 45) of the serum samples from these CE and AE patients, respectively. By the ELISA, both EmAgB8/1 and EgAgB8/1 exhibited similar positive reactions with 88% (44 of 50) of serum samples from CE patients and 37.8% (17 of 45) serum samples from AE patients. Statistical analysis revealed that the sensitivity of EmAgB8/1 was comparable to that of EgAgB8/1 for the serodiagnosis of echinococcal diseases. There was no cross-reaction with sera from patients with cysticercosis, which often cross-react when native antigens are used for serodiagnosis.

Amino Acid Sequence↗
PubMed1978

Echinococcus granulosus: specific quantification of the two most immunoreactive antigens in hydatid fluids.

Preparations of the two most immunoreactive Echinococcus granulosus antigens (antigens 4 and 5) from sheep hydatid fluid, purified by a simplified method, and monospecific antisera against antigens 4 and 5, prepared by a new procedure, were used to measure the antigenic concentrations of antigens 4 and 5 in swine, sheep, and human hydatid fluids from pulmonary or hepatic cysts. Two bovine samples and two commercial preparations were also tested. The concentration of both antigens was significantly higher in sheep and human hydatid fluids than in swine hydatid fluid. The antigenic content of the two bovine samples and of the two commercial preparations was below the sensitivity level of the method employed. Independently of the species tested, the amount of Echinococcus antigens was greater in hepatic than in pulmonary cysts. The ratio between the concentrations of antigens 4 and 5 was constant at about 1:10 in the samples from various organs and from different species. When there were enough samples for statistical analysis a linear correlation was found between the contents of these two antigenic components but there was none between the amounts of proteins and the antigenic concentrations in the single cysts. Sheep hydatid fluid must therefore be considered the best source of antigenic material for diagnostic purposes even though in human cysts the antigenic fraction is less contaminated by serum proteins. We describe a reliable method of standardising antigenic material for the immunodiagnosis of hydatid disease.

Animals↗
PubMed2002

Meriones meridianus and Lagurus lagurus as alternative definitive hosts of Echinococcus multilocularis and E. granulosus.

The utilization of Meriones meridianus and Lagurus lagurus as alternative definitive hosts for Echinococcus multilocularis and E. granulosus was investingated. Tapeworm stage development of E. multilocularis was observed and their recovery rate was determined in the small intestine of M. meridianus and L. lagurus. These were compared with those in golden hamsters, which are known as alternative definitive hosts. The animals were treated with PTBA (prednisolone tertiary butylacetate) and PA (prednisolone acetate), after which M. meridianus showed the highest recovery rate, whereas L. lagurus had few or no worms. The recovery rate of worms from golden hamsters was between those of M. meridianus and L. lagurus. On day 20 post-infection, developing tapeworms with mature segments were collected from M. meridianus treated with PA. The worms were mostly from the proximal and medial small intestine. The three species of animals infected orally with E. granulosus were divided into two groups, PTBA-treated and non-treated control groups. PTBA promoted/enhanced the recovery rate of the worms until 5 days, but none or only a few worms were found in PTBA treated animals thereafter. The highest recovery rate was obtained from M. meridianus treated with PTBA on day 5 post-infection. Some worm developments were observed on days 5 and 10 post-infection. These results demonstrate that M. meridianus could be useful as an alternative definitive host of Echinococcus.

Animals↗
PubMed2004

First report of a human case of polycystic echinococcosis due to Echinococcus vogeli from neotropical area of Peru, South America.

We report a human case of polycystic hidatidosis due to Echinococcus vogeli from Contamana (Department of Loreto) village located in the central jungle of Peru. The patient is a 44 year-old lady, teacher, who carried a painless liver mass since a year ago. She was submitted to abdominal surgery and the liver mass was removed and showed multiple cysts containing colorless liquid as is showed in the polycystic hidatidosis. The morphology and measure of the hooks obtained from the liquid contained in the cysts are from Echinococcus vogeli. It is the first report of this parasitism in Perú.

Adult↗
PubMed2006

New data on Echinococcus spp. in Southern Brazil.

40 Echinococcus isolates from sheep and cattle in Southern Brazil were genetically analysed in order to obtain further data on the presence of different taxa of the Echinococcus granulosus complex. Differentiation was done using a PCR technique and sequencing of mitochondrial cytochrome c oxidase subunit 1 (CO1). Most samples (38) could be allocated to the sheep strain (G1) of E. granulosus, while two samples belonged to E. ortleppi, previously known as cattle strain (G5) of E. granulosus. Due to the shorter prepatent period in dogs of the latter taxon, this records have important implications for the design of control measures in this endemic region.

Animals↗
PubMedDate not supplied

[Echinococcus vogeli cysts in paca liver (Cuniculus paca) native from the Acre State, Brazil].

Four of the patients with polycystic hydatid disease observed by us reported that they were aware of the presence of liver disease in the pacas hunted for food. The viscera of these animals were usually given to domestic dogs. All of our 7 patients reported contact with dogs that had previously ingested viscera of pacas. Examination of the liver considered to be diseased by one of the patients and removed from a paca killed in the same region (State of Acre, Brazil) from which the human cases originated showed the presence of hydatid cysts. The characteristics of the rostellar hooks of the protoscolex indicated that this was the larval form of Echinococcus vogeli. These observations confirm the participation of pacas in the biological cycle of E. vogeli and the pathway through which man may become an alternative intermediate host of this echinococcus.

Animals↗
PubMed2003

Observations on the development of Echinococcus multilocularis in cats.

The development of a European isolate of Echinococcus multilocularis was compared in cats and dogs at the end of the prepatent period. Echinococcus multilocularis established in all dogs and cats, but worm recovery was significantly greater from dogs than from cats. Overall, worms in cats were not as advanced as those in dogs in terms of development and maturation, but there was no evidence of retarded development or stunted forms. These results confirm that dogs are highly susceptible to E. multilocularis, whereas cats have lower and more variable recovery rates. However, because cats produce thick-shelled eggs of E. multilocularis after experimental and natural infections, they have to be regarded as potential sources of infection both for intermediate and accidental hosts, including humans. However, their general role in the epidemiology of the infection has yet to be determined.

Age Factors↗
PubMed2005

Reemergence of canine Echinococcus granulosus infection, Wales.

As a consequence of large-scale outdoor slaughter of sheep during the 2001 foot and mouth disease (FMD) outbreak in the United Kingdom and the possibility of increased risk for transmission of Echinococcus granulosus between sheep and dogs, a large survey of canine echinococcosis was undertaken in mid-Wales in 2002. An Echinococcus coproantigen-positive rate of 8.1% (94/1,164) was recorded on 22% of farms surveyed, which compares to a rate of 3.4% obtained in the same region in 1993. Positivity rates between FMD-affected properties and unaffected ones did not differ significantly. Significant risk factors for positive results in farm dogs were allowing dogs to roam free and the infrequent dosing (>4-month intervals) of dogs with praziquantel. When these data are compared to those of a previous pilot hydatid control program in the area (1983-1989), an increase in transmission to humans appears probable.

Animals↗
PubMed1998

Short report: An imported case of cystic echinococcosis in Japan diagnosed by imaging and serology with confirmation of Echinococcus granulosus-specific DNA sequences.

We report one case of cystic echinococcosis (CE) in Japan in a native of Nepal. Ultrasonography and computed tomography scan of the liver revealed unique cystic lesions with or without daughter cysts of Echinococcus granulosus. Immunoblot analysis using crude antigens of E. multilocularis and cyst fluid of E. granulosus, without reference to these image analyses, strongly suggested this was a case of CE. We found protoscoleces in surgically removed hepatic lesions and analyzed the mitochondrial cytochrome c oxidase subunit I (COI) gene by the polymerase chain reaction. Based on the similarity in DNA sequences of the COI gene of this Echinococcus spp. with that of previously reported sheep-dog strain (GI), the parasite was considered to be the so-called common sheep strain of E. granulosus.

Adult↗
PubMed2002

Two atypical cases of cystic echinococcosis (Echinococcus granulosus) in Alaska, 1999.

Before 1999, clinical experience demonstrated that the sylvatic (or Northern) biotype of Echinococcus granulosus seen in Alaska produced fewer complications and serious sequelae than infection with the pastoral (or European) biotype found in other parts of the world. Two cases of E. granulosus with severe sequelae occurred in Alaska in 1999. The adverse outcomes could have been rare complications that are part of the clinical spectrum of disease caused by sylvatic cystic echinococcus, an indication that the sylvatic biotype, especially when affecting the liver, has potential for severe clinical consequences, or perhaps in one case, infection with a more virulent biotype of E. granulosus contracted during visits to Washington State.

Adolescent↗
PubMed2006

Helminthologic survey of the wolf (Canis lupus) in Estonia, with an emphasis on Echinococcus granulosus.

Carcasses of 26 wolves were collected during the 2000/2001 and 2003/2004 hunting seasons and examined for helminths. Thirteen helminth species were recorded: one trematode (Alaria alata), seven cestodes (Diphyllobothrium latum, Mesocestoides lineatus, Taenia hydatigena, Taenia multiceps, Taenia ovis, Taenia pisiformis, and Echinococcus granulosus), and five nematode species (Uncinaria stenocephala, Toxascaris leonina, Toxocara canis, Trichinella nativa, and Trichinella britovi). The most common species were A. alata and U. stenocephala. Mature Echinococcus granulosus was found and described for the first time in Estonia, and its identity verified using PCR-RFLP analysis. Sequencing a fragment of the mitochondrial DNA NADH dehydrogenase 1 (mtND1) gene showed that the E. granulosus strain from Estonia was identical to strain G10, recently characterized in reindeer and moose in Finland.

Animals↗
PubMed1999

Monoclonal antibodies specific to carbohydrates of Echinococcus multilocularis.

To investigate the complexity of epitopes presented on Echinococcus multilocularis (E.m.) metacestode carbohydrates, a panel of monoclonal antibodies (MoAbs) was generated and characterized. Thirty of the clones were obtained and classified into three types (types I to III) based on Western blotting (WB) and dot-ELISA. One MoAb (type I) appeared to react with one of the carbohydrate antigens (C-antigens) located at 30-35 kDa, and was the most effective diagnostic antigen for human alveolar hydatid disease (AHD) in Hokkaido, Japan. The second group (15 clones) of MoAb (type II) reacted with another C-antigen; one which also induced antibody response in AHD patients. The third group (14 clones) of MoAb (type III) reacted with other C-antigens both in ELISA and dot-ELISA, but did not react in WB. Cross-reaction to the antigens of Echinococcus granulosus was faintly observed in only the type I-MoAb by dot-ELISA. In the immunohistological studies, all of the MoAbs reacted strongly with the laminated layer though not with protoscoleces in metacestode tissue prepared from experimentally infected cotton rats. Tissue sections treated with sodium periodate lost their immunoreactivity, suggesting that these MoAbs recognized carbohydrate epitopes of the E.m. metacestode.

Animals↗
PubMed2000

[Control of Echinococcus multilocularis in Central Europe-- possibilities and limitations].

Human alveolar echinococcosis is a life-threatening parasitic zoonosis which occurs in rare cases in Central Europe. It is caused by the larval stage of Echinococcus multilocularis. In this publication, strategies for the control of parasites of the genus Echinococcus are reviewed and discussed with regard to their applicability to E. multilocularis on the background of the epidemiological situation in Central Europe. First results of field studies are presented in which strategies based on the application of praziquantel-containing baits to foxes have been tried. Requirements concerning the surveillance of control measures are demonstrated and the limitations of the imaginable control strategies discussed.

Animals↗
PubMed1975

Sylvatic echinococcosis in Argentina. I. On the morphology and biology of strobilar Echinococcus granulosus (Batsch, 1786) from domestic and sylvatic animal hosts.

Dogs were fed larvae of Echinococcus granulosus (Batsch, 1786) recovered from sheep in Argentina. The morphological characteristics of strobilae recovered from dogs at 28, 60 and 76 days postexposure were compared with those of Echinococcus spp. recovered from naturally infected foxes, Dusicyon clupaeus (Molina) and D. griseus (Gray), and those of worms reared in dogs from larvae in European hares, Lepus europaeus (L.). Only slight differences were observed in characters of taxonomic importance and it was concluded that all cestodes represented a single species, E. granulosus. The results are discussed as they bear on the speciation controversy and the potential epidemiology importance of Dusicyon spp. as hosts of E. granulosus. It was suggested that E. patagonicus Szidat, 1960 previously described from D. culpaeus is conspecific with E. granulosus. E. cepanzoi Szidat, 1971 is probably also a synonym of E. granulosus and the subspecies E. g. dusicyontis Blood and Lelijveld, 1969, is rejected on the grounds that there is no evidence for host specificity and ecological or other segregation from the nominate form. Foxes appear to become infected from scavenging on dead sheep in localities where E. granulosus is endemic in domestic animals. There is still no evidence that E. granulosus is maintained in Argentina in sylvatic cycles.

Animals↗
PubMed1998

[Establishment of germinal cell line of Echinococcus granulosus].

AIM: To establish a cell line of Echinococcus granulosus. METHODS: The proliferating membranes striped from liver cysts in a naturally infected sheep from Urumq were released to monodispersed germinal cells by grinding. The germinal cells were cultivated in the RPMI 1640 medium supplemented with 10%-20% calf serum on collagen-coated 24-well culture plate alternately from passage 1 to passage 14, and then continued. The morphological feature and growth situation were observed by light microscopy. The cultured cells were inoculated into BALB/c mice to identify the infectivity. ELISA was used to determine the immunogenicity of the cells. RESULTS: The germinal cells have been cultivated continuously up to passage 75. The subcultured cells were circular in shape with smooth surface and had the tendency to form syncytia and tissue-like masses. The cells from this cell line could be stored for at least 15 days in refrigerator at 4 degrees C and 10 months in liquid nitrogen. No cyst materials were detected in the mice inoculated with cells. The antigens from cell line could react with positive sera from mice infected with protoscoleces and sera against secreted antigens of cyst membrane, soluble antigens from cyst membrane, soluble antigens from protoscoleces and SHF. CONCLUSION: A germinal cell line of Echinococcus granulosus was successfully established.

Animals↗