Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Echinococcus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2001

Construction and primary characterization of Echinococcus multilocularis protoscolex cDNA expression library.

OBJECTIVE: To construct a lambda gt11 cDNA expression library of Echinococcus multilocularis protoscolex isolated in China. METHODS: Echinococcus multilocularis protoscolex mRNA was extracted using a Quickprep MicromRNA purification kit based on combining of the disruptive and protective properties of guanidinium thiocyanate (GTC) with the speed and selectivity of oligo (dT)-cellulose chromatography in a spum-column with some modification. Purified mRNA (1.8 micrograms) was submitted to reverse transcription using random hexamers [pd(N6)]. The double-strand blunt-ended cDNAs were ligated with an EcoRI/Notl adaptor to form a cohesive EcoRI end. Subsequently the synthesized cDNA was inserted into vector lambda gt11 EcoRI arms. After being packaged in vitro, lambda gt11 was put to an infectious bacteria Echinococcus coli (E. coli) strain Y1090; the recombinants were screened by color selection. PCR amplification was performed to evaluate the size of insertion DNA fragments. RESULTS: The recombinant ratio was nearly 100% and approximately 1 x 10(6) clones could be derived from this lambda gt11 cDNA library. PCR results indicated that the insertion DNAs were about 1.48 kb. CONCLUSIONS: A lambda gt11 cDNA expression library consisting of a million recombinant clones has been constructed from Echinococcus multicularis protoscolex mRNA. Further studies on this library are deserved.

Animals↗
PubMed2004

The diagnosis of Echinococcus granulosus in dogs.

The problem of diagnosing Echinococcus granulosus in dogs has still only been partially resolved, even after the advent of biotechnology. The eggs of taeniid Cestoda are extremely similar, and thus identification by microscopic examination of the faeces is risky and non-specific. For this reason, Echinococcus granulosus was traditionally diagnosed in dogs ante mortem after an arecoline hydrobromate purge. The faeces were examined macro and microscopically to establish if the adult tapeworm or its proglottids were present. Although this method is 100% specific, it is bio-hazardous and time-consuming, requires trained personnel, and its sensitivity varies. In the 1990s copro-antigens were discovered and characterised. These are released by the adult worm in the faeces. This made it possible to use enzyme-linked immune-adsorbent assay (ELISA) for in vitam diagnosis of Echinococcus granulosus. In recent years several PCR protocols have been published on the identification of Echinococcus granulosus DNA from eggs or from adult parasites and new ways of diagnosing this cestode have been developed.

Animals↗
PubMed2006

Dual infection of animal hosts with different Echinococcus species in the eastern Qinghai-Tibet plateau region of China.

The eastern Qinghai-Tibet plateau of China is a highly endemic region of echinococcosis where Echinococcus granulosus sensu stricto (sheep strain), Echinococcus multilocularis, and Echinococcus shiquicus are distributed sympatrically. We developed a polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method for the identification of the three species in this region. The PCR-RFLP showed the dual infection of animals with different Echinococcus spp. The first case was a domestic dog concurrently infected with adults of E. granulosus and E. multilocularis. The second case was a plateau pika (Ochotona curzoniae) harboring metacestodes of E. multilocularis and E. shiquicus in the liver. The high susceptibility of some mammalian hosts to the parasites and the high prevalence of the three co-endemic species probably increase the chance of mixed infections in the eastern Tibetan plateau.

Animals↗
PubMed1994

Detection of Echinococcus coproantigens in stray dogs of northern Spain.

An enzyme-linked immunosorbent assay (ELISA) was assessed for its suitability to diagnostically detect Echinococcus coproantigens in fecal samples of dogs infected with E. granulosus. The specificity of the test was determined by investigating fecal samples from 177 Echinococcus-free dogs infected with Taenia spp., 41 dogs with non-taeniid helminths and 24 dogs free of helminth infections. An overall specificity of 97% was determined. The diagnostic sensitivity was in close association to the worm burden of infected individuals: when dogs harboured less than 100 worms, six from 21 samples (29%) were found to be positive in coproantigen ELISA, whereas sensitivity was much higher (23 ELISA-positive from 25 samples = 92%) when dogs had more than 100 worms. Despite the relatively low average sensitivity (63%), the test enabled detection of more than 90% of the biomass of adult Echinococcus present in the respective dog populations. Conclusively, coproantigen detection allows diagnosis of most individual intestinal Echinococcus infections relevant for the egg contamination of the environment and is therefore a valuable tool to determine the relative prevalence of adult stage E. granulosus prevalence in a given endemic area.

Animals↗
PubMed2004

[Laboratory evaluation of commercial immunoblot assay kit for serodiagnosis of Echinococcus infections using sera from patients with alveolar hydatidosis in Hokkaido].

Using serum specimens from patients with alveolar hydatidosis (AH) in Hokkaido, we assessed the usefulness of "Echinococcus Western Blot IgG" (the French immunoblot assay, FIA), which has recently been launched from Ldbio Diagnostics (Lyon, France) as new commercial immunoblot assay kit of immunodiagnosis of Echinococcus infections. Eighty serum specimens were used for the present study: 64 preoperative sera and nine postoperative sera, which were taken from AH patients in Hokkaido, and seven sera from persons who were ELISA (enzyme-linked immunosorbent assay)--positive in mass screening which was conducted for checking on Echinococcus infections in Hokkaido since 1982. When the 64 preoperative sera were examined by the Western blotting method (the Hokkaido method of Western blotting, HWB) which had been carried out at Hokkaido Institute of Public Health between 1987 and 1993, it was found that 53 cases were positive and six cases were quasi-positive, i.e. the rate of the positive cases including quasi-positive cases was 92.2%. From immunostaining patterns, HWB-positive sera could be grouped in two types: the complete type, which showed a pattern of multiple bands containing the 55 and 66 kDa bands, and the incomplete type, which showed patterns of only few bands containing the AH-specific polysaccharide antigen named C antigen. Forty-three of the 53 HWB-positive sera were of the complete type and the residue was of the incomplete type. On the other hand, when the 64 preoperative sera were examined by FIA, 60 sera (93.8%) were judged to be positive and the others as negative sera. On the basis of the interpretation of immunostaining patterns described in the instruction manual, 47 (78.3%) of the 60 positive sera were regarded as pattern P3, five (8.3%) as pattern P4, and eight (13.3%) as pattern P5. All of the complete-type sera were regarded as P3, indicating high antibody titers. Contrarily, most of the incomplete-type or quasi-positive sera resulted in other patterns such as P4 and P5, indicating low antibody titers. Of 5 HWB-negative sera, two were FIA-positive (which showed P3 and P5 patterns respectively), however their immunoreactions were significantly low. Therefore, apart from interpretation of pathological conditions of cases with exceedingly low antibody titers, FIA may be able to give a serologically clear interpretation to HWB-quasi-positive cases, indicating that it is a highly sensitive and useful method for immunodiagnosis of Echinococcus infections.

Echinococcosis, Pulmonary↗
PubMed2006

[Rare case of huge echinococcus of the liver].

A huge echinococcus, 26-16 cm in size, of the right lobe of the liver was diagnosed by means of echoscopy and radiology in the man 53 years of age. During operation 3000 ml of transparent liquid with daughter bubbles were taken out from the echinococcus cavity. Partial resection of the right lobe of the liver and drainage of the echinococcus cavity were made transhepatically with two drainages. During the postoperative period everyday sanitation of the cavity with antiseptic solutions was done. Periodically echoscopic monitoring of the echinococcus cavity was also done. The cavity gradually decreased in volume and after three months it was closed.

Diagnosis, Differential↗
PubMed2004

Echinococcus multilocularis laminated-layer components and the E14t 14-3-3 recombinant protein decrease NO production by activated rat macrophages in vitro.

Echinococcus multilocularis and Echinococcus granulosus cause alveolar and cystic (unilocular) echinococcosis, respectively, in humans and animals. It is known that these parasites can affect, among other molecules, nitric oxide (NO) production by periparasitic host cells. Nevertheless, detailed dissection of parasite components specifically affecting cell NO production has not been done to date. We compare the effect of E. granulosus and E. multilocularis defined metacestode structural (laminated-layer associated) and metabolic (14-3-3 protein, potentially related with E. multilocularis metacestode tumor-like growth) components on the NO production by rat alveolar macrophages in vitro. Our results showed that none of these antigens could stimulate macrophage NO production in vitro. However, a reversed effect of some Echinococcus antigens on NO in vitro production was found when cells were previously exposed to LPS stimulation. This inhibitory effect was found when E. multilocularis laminated-layer (LL) or cyst wall (CW) soluble components from both species were used. Pre-stimulation of cells with LPS also resulted in a strong, dose-dependent reduction of NO and iNOS mRNA production after incubation of cells with the E14t protein. Thus, the E. multilocularis 14-3-3 protein appears to be one of the components accounting for the suppressive effect of the CW and LL metacestode extracts.

14-3-3 Proteins↗
PubMed2005

Molecular study of Echinococcus in west-central China.

West-central China is an important endemic focus of both alveolar and cystic echinococcosis where several species of intermediate host are commonly infected with Echinococcus granulosus and E. multilocularis . Isolates of E. granulosus were collected from humans and other animals from different geographical areas of Qinghai, Ningxia, Gansu and Sichuan, and genotyped using the mitochondrial DNA marker ATP synthase subunit 6 gene (atp6). The sheep strain (G1 genotype) of E. granulosus was shown to be the only genotype present in sheep, cattle, goats, yaks and humans in the study areas. However, some heterogeneity in the atp6 sequence was evident in a number of the isolates with the most frequent change being a silent substitution (G/A) at position 360 compared with the G1 reference sequence representing isolates collected from the majority of hosts except humans. Two E. multilocularis isolates examined also had sequences that varied from each other and from the reference E. multilocularis atp6 sequence. The genotypic variation we report may reflect phenotypic differences with important consequences in terms of increased host infectivity for hosts by local Echinococcus strains, possibly impacting on the epidemiology and control of echinococcosis. Such adaptations may also result in different sensitivity to drugs or increased virulence for hosts that will impede control efforts and even affect vaccination strategies against Echinococcus.

Adaptation, Physiological↗
PubMed1982

A review of the taxonomy and speciation of the genus Echinococcus Rudolphi 1801.

The taxonomy of Echinococcus is reviewed and consideration given to speciation within the genus. The morphological and other biological characteristics of all species and subspecies so far described are given, and evidence for the existence of other intraspecific variants is presented. A total of 16 species have been described but only four have well-defined characteristics and are generally accepted as being taxonomically valid; E. granulosus, E. multilocularis, E. oligarthrus and E. vogeli. The taxonomic status of intraspecific variants is uncertain. Some authorities consider that the majority of described subspecies are invalid taxonomically. However, concern is expressed that previous taxonomic considerations of Echinococcus have not taken into account the nature of its reproductive mechanism which, like that of most cestodes, defies the application of traditional taxonomic concepts and definitions derived from dioecious cross-fertilising organisms. At the present time intraspecific variants of Echinococcus are referred to as strains. The existence of such strains, particularly of E. granulosus, in different parts of the world is firmly established. Their importance in the epidemiology of hydatidosis has high-lighted the needed to establish criteria for their differentiation and characterisation. The limitations of morphology as a sole differential criterion are emphasised. Attention is given to recent studies on strain variation which have demonstrated the value of applying several different criteria in which the developmental, physiological and biochemical characteristics of different strains are compared in conjunction with morphological investigations.

Animals↗
PubMed1989

Subunit composition and specificity of the major cyst fluid antigens of Echinococcus granulosus.

The subunit composition and specificity of the major Echinococcus granulosus cyst fluid antigens were determined by immunochemical analysis using murine monoclonal antibodies against Antigen 5 and Antigen B and human sera. Immune complexes cut out from immunoelectrophoresis gels and murine hybridomas were used as a source of specific anti-Antigen 5 and anti-Antigen B antibodies. Immunoprecipitation and Western blot analyses in sodium dodecyl sulphate-polyacrylamide gels using these reagents identified Antigen 5 to be a heterodimer composed of 24-kDa and 38-kDa subunits linked by disulphide bonding. Antigen B comprised a regularly spaced group of molecules with the smallest subunit estimated to be 8 kDa and the other components each differing in size by approximately 8 kDa, i.e., 16 kDa, 24 kDa, 32 kDa etc.; all possibly derived from the 8-kDa monomer. The relative abundance of the Antigen B subunits decreased asymptotically with increasing molecular weight. Neither the Antigen 5 nor the Antigen B subunit was specific for E. granulosus. Both antigens generated readily detectable levels of specific antibody in the sera of patients with Echinococcus multilocularis, Echinococcus vogeli or E. granulosus infection. Relatively high levels of antibody to Antigen 5 were also detected in the sera of patients infected with Taenia solium. The presence of phosphorylcholine epitope(s) on Antigen 5 was confirmed.

Animals↗
PubMed1991

Sequencing and characterization of an Echinococcus multilocularis DNA probe and its use in the polymerase chain reaction.

The nucleotide sequence of the cloned Echinococcus multilocularis DNA probe pAL1 was determined in order to simplify and improve the sensitivity of a diagnostic assay through the application of the polymerase chain reaction (PCR). The insert-specific oligonucleotides BG1 and BG2 define a 2.6-kb fragment in the genomic DNA of E. multilocularis, while BG1 and BG3 define a 0.3 kb fragment. A PCR study including 14 independent E. multilocularis isolates in addition to Echinococcus granulosus. Echinococcus vogeli, Taenia spp. and other cestodes revealed that the 2.6-kb fragment was amplified from genomic DNA of all E. multilocularis isolates tested (originating from Switzerland, Alaska, Canada, France, Germany and Japan), but from genomic DNA of none of the other cestode species. PCR with BG1 and BG2 furthermore uniquely resulted in the synthesis of a 0.55-kb fragment specific for Taenia saginata and a 0.6-kb fragment specific for T. taeniaeformis. In contrast to the species specificity of the 2.6-kb BG1/BG2 product, the 0.3 kb (BG1/BG3) product demonstrated genus specificity: the 0.3-kb product was amplified from genomic DNA of all E. multilocularis, E. granulosus and E. vogeli isolates tested, but from genomic DNA of none of the other cestode species. The diagnostic sensitivity of PCR using both primer sets was determined to be 50 pg parasite DNA, suggesting the practical utility of this simple assay in demonstrating parasite DNA in specimens from a variety of sources. At the basic level, the pAL1-derived oligonucleotides may also prove useful in assessing strain variation, RFLPs or other manifestations of genetic variation in E. multilocularis.

Animals↗
PubMed1993

Rapid discrimination of Echinococcus species and strains using a polymerase chain reaction-based RFLP method.

Echinococcus species and genetically distinct strains of Echinococcus granulosus can be rapidly and reliably identified using a polymerase chain reaction (PCR)-linked restriction fragment length polymorphism (RFLP) method which surveys the sequence of a rapidly evolving region of the ribosomal DNA (rDNA) unit. Internal transcribed spacer 1 (ITS1) of the rDNA repeat was amplified from various isolates and the product was digested with one of a number of 4-base cutting restriction enzymes. Characteristic patterns were produced when samples within various species and strain groups were analysed. This method offers an objective, simple, highly sensitive and rapid approach for the discrimination of Echinococcus isolates and for study of other parasite complexes.

Animals↗
PubMed2005

Echinococcus multilocularis: cloning and characterization of a member of the SNW/SKIP family of transcriptional coregulators.

We have isolated a cDNA from the fox-tapeworm Echinococcus multilocularis that encodes EmSkip, a novel member of the SNW/SKIP family of transcriptional coregulators. EmSkip displays significant amino acid sequence homologies to already known members of the protein family and contains all the characteristic amino acid residues at their corresponding positions. RT-PCR experiments showed that the EmSkip encoding gene, emskip, is expressed in the Echinococcus larval stages metacestode and protoscolex during an infection of the intermediate host. By yeast two-hybrid analyses, EmSkip was found to be capable of forming homodimers in vivo. Furthermore, EmSkip was found to interact with EmSmadA and EmSmadB, two previously identified TGF-beta/BMP signal transducers of E. multilocularis, indicating a role of this protein in TGF-beta signaling processes in the parasite. In view of the role played by SNW/SKIP proteins in splicing mechanisms and intracellular signaling, the data presented herein should facilitate the identification of Echinococcus factors involved in such processes.

Amino Acid Sequence↗
PubMed2006

Expression and diversity of Echinococcus multilocularis AgB genes in secondarily infected mice: evaluating the influence of T-cell immune selection on antigenic variation.

The T-cell-mediated immune response exhibits a crucial function in the control of the intrahepatic proliferation of Echinococcus multilocularis larvae in mice and humans, both being natural intermediate hosts of the parasite. Antigen B (AgB), a metabolized Echinococcus spp. lipoprotein, contributes to the modulation of the T-cell immune response, and distinct sites of the corresponding AgB1, AgB3 and AgB4 genes were shown to be under positive selection pressure. Since several AgB gene variants are present in a single Echinococcus metacestode, we used secondary E. multilocularis infections in BALB/c and in athymic nude mice (devoid of T-cell responses) to analyze the effect of the cellular immune response on the expression and diversity of EmAgB1-EmAgB4 genes. We demonstrated hereby that EmAgB transcripts were less abundant in nude mice during the early phase of infection (at one month post-infection), and that EmAgB2 is simultaneously down-regulated when compared to the other three genes. A negative relationship exists between the level of transcription and diversity of EmAgB genes. Moreover, no excess of non-synonymous substitutions was found among the distinct EmAgB alleles from a single host. Together, these results pointed to the effect of purifying selection, which seemed to eliminate the detrimental AgB variants generated during the development of the metacestode within the peritoneal cavity of its intermediate host.

Animals↗
PubMed2006

Characterisation of EmMPK1, an ERK-like MAP kinase from Echinococcus multilocularis which is activated in response to human epidermal growth factor.

Mitogen-activated protein (MAP) kinases are key regulators of cellular signalling systems that mediate responses to a wide variety of extracellular stimuli and should also play a central role in developmental mechanisms of parasitic helminths. Until now, however, no MAP kinase orthologue has been characterised in a member of this parasite group. Here, we report the identification and characterisation of such a molecule, EmMPK1, from the human parasitic cestode Echinococcus multilocularis. Using a degenerative PCR approach, we isolated and completely sequenced the 1.2kb cDNA for EmMPK1 which displays significant homologies to known MAP kinases of different phylogenetic origin. EmMPK1 contains all amino acid residues which are characteristic for MAP kinases, including a conserved TEY motif which identifies the protein as a member of the ERK subfamily of MAP kinases. The corresponding gene, emmpk1 (6.9 kb), was characterised and contained 10 introns. Southern blot hybridisation studies showed that emmpk1 is present as single copy locus in E. multilocularis. Using RT-PCR analyses we demonstrated that emmpk1 is expressed in form of three different transcripts which derive from alternative splice acceptor site utilisation at intron 9. Using EmMPK1-specific antibodies in Western blot studies and immunohistochemistry, we detected the Echinococcus protein and its phosphorylated form in the larval stages metacestode and protoscolex during in vitro cultivation and during an infection of the intermediate host. EmMPK1, immunoprecipitated from Echinococcus lysate, was able to phosphorylate myelin basic protein in activity assays, indicating that it is a functionally active MAP kinase. Finally, we also show that phosphorylation of EmMPK1 is specifically induced in vitro-cultivated E. multilocularis metacestode vesicles in response to exogenous host serum and upon addition of human epidermal growth factor. These data indicate that the E. multilocularis metacestode is able to sense epidermal growth factor from the host which results in an activation of the parasite's MAP kinase cascade.

Alternative Splicing↗
PubMed2005

Detection of Echinococcus multilocularis in wild boars in France using PCR techniques against larval form.

Recently, new data have been collected on the distribution and ecology of Echinococcus multilocularis in European countries. Different ungulates species such as pig, goat, sheep, cattle and horse are known to host incomplete development of larval E. multilocularis. We report a case of E. multilocularis portage in two wild boars from a high endemic area in France (Department of Jura). Histological examination was performed and the DNA was isolated from hepatic lesions then amplified by using three PCR methods in two distinct institutes. Molecular characterisation of PCR products revealed 99% nucleotide sequence homology with the specific sequence of the U1 sn RNA gene of E. multilocularis, 99 and 99.9% nucleotide sequence homology with the specific sequence of the cytochrome oxydase gene of Echinococcus genus and 99.9% nucleotide sequence homology with a genomic DNA sequence of Echinococcus genus for the first and the second wild boar, respectively.

Animals↗
PubMed1997

Intraspecific variation of Echinococcus granulosus and related species with emphasis on their infectivity to humans.

Four species are presently recognised within the genus Echinococcus, namely Echinococcus granulosus, E. multilocularis, E. oligarthrus and E. vogeli, which are infective to humans. Evidence for strain diversity within the species E. granulosus, previously mainly based on morphological, biological and biochemical features, has been principally confirmed by recent genetic studies. Several molecular techniques are now available which allow the identification of E. granulosus strains. Epidemiological evidence and molecular studies indicate that the so-called sheep, cattle and cervid strains of E. granulosus are infective to humans, while the horse, camel and pig strains may be less or not infective, but this question warrants further studies. A recent study indicates that E. granulosus infecting patients in Poland shares close molecular affinity with a genotype of pig origin (G7) but exhibits some clear differences. Therefore, it may represent a previously undescribed genotype of E. granulosus, designated as G9. Phylogenetic analysis of molecular data has demonstrated the need to reappraise the taxonomic status of currently recognised strains. Clear evidence for strain variation in the other species of Echinococcus does not exist at present.

Animals↗
PubMed2000

Efficacy of Droncit Spot-on (praziquantel) 4% w/v against immature and mature Echinococcus multilocularis in cats.

The causative agent of alveolar hydatidosis in humans, the fox tapeworm Echinococcus multilocularis, is extending its geographical range in Europe and has been found in domestic cats in some areas. A dermally applied cestocidal treatment for domestic cats has been developed and the efficacy of this treatment is reported. Thirty purpose-bred cats were experimentally infected each with 10000 protoscoleces of Echinococcus multilocularis. Ten days later one group of ten cats was treated with Droncit(R) Spot-on (Praziquantel) 4% w/v dermally in one place on the dorsal aspect of the neck at a dose of 8 mg/kg. Eleven days later (21 days p.i.) a second group of ten cats was also treated with Droncit(R) Spot-on the same way. One group of ten cats was left untreated as controls. Twenty three days after infection the cats were examined for the presence of E. multilocularis tapeworms. No E. multilocularis were recovered from any of the cats in either of the treated groups. Echinococcus multilocularis were recovered from eight of the ten cats left untreated as controls. The worm burdens in the untreated cats were 0, 0, 5, 15, 75, 110, 220, 815, 2635, and 3045 worms per cat. The worms ranged in development from the three to four segment stage. Many of the E. multilocularis with four segments contained unshelled eggs in the terminal segment. This study indicates that Droncit(R) Spot-on (Praziquantel) 4% w/v applied dermally at 8 mg/kg is highly effective in removing E. multilocularis from the small intestine of cats infected with immature and mature (prepatent) infections of E. multilocularis. In the cats with the mature infections all tapeworms were absent from the small intestine within 2 days of treatment.

Animals↗