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PubMed1995

Specific diagnostic antigens of Echinococcus granulosus detected by western blot.

A western blot assay was performed for the detection of Echinococcus granulosus specific antigens useful for the diagnostic of hydatic disease. 191 sera were tested, 105 coming from patients with different localizations of hydatic cysts and 86 from persons either healthy or presenting other diseases. 48 different antigenic bands were detected using sera from patients with hydatidosis. A 35 kDa antigen co-migrating with a band labeled by a McAb specific of antigen 5 was recognized in western blot by only 68% of the sera able to precipitate antigen 5 in immunoelectrophoresis. A 8 kDa antigen corresponding to the specific E. granulosus antigen already described has been recognized by 80% of the sera coming from patients with hydatidosis and not by the 86 control sera. Bands of 21, 30, and 92 kDa appeared also specific and were recognized by at least 50% of tested sera. These antigens appeared unrelated one to each other. 103 out of the 105 sera from patients with hydatidosis were able to recognize at least one of the 8, 21, 30, 35 or 92 kDa specific antigens. The present results suggest that western blot could be useful for the diagnosis of hydatidosis as far as the criteria of positivity is based on the recognition of at least one of the major specific antigens.

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↗
PubMed2000

Presence of cholinesterases in Echinococcus granulosus protoscolices.

Cholinesterases were detected in protoscolices of Echinococcus granulosus spectrophotometrically and electrophoretically. To characterize these activities as acetylcholinesterases or pseudocholinesterases, BW284C51 and the organophosphate anthelmintic Neguvón were assayed as specific inhibitors of acetylcholinesterases, while Iso-OMPA was employed as specific inhibitor of pseudocholinesterases. We concluded that these cholinesterase (ChE) activities would be considered as possible targets in chemotherapy.

Acetylcholinesterase↗
PubMed2001

Free amino acid concentration in hydatid cyst fluids from fertile and infertile human and animal Echinococcus granulosus.

The aim of this study was to search and compare free amino acid composition of fertile and infertile cyst fluids obtained from humans and animals infected naturally with Echinococcus granulosus, by using automated analysis based on cation-exchange chromatography with post-column ninhydrin derivatization system. 11 free amino acids from fertile (sheep origin), nine from infertile (cattle origin), 13 from infertile (human origin) hydatid cyst fluids and 19 amino acids from sera of patients with hydatid infection were detected. The levels of glycine, alanine, valine and lyrosine in fertile and infertile hydatid cysts fluids were significantly higher than in sera from patients with hydatid cysts. Glycine level in the fertile hydatid cyst fluids (sheep origin) was significantly higher than those of infertile cysts fluids (cattle and human origin) and sera with hydatid patients. Glycine level in fertile hydatid cyst fluids was about two times more concentrated in infertile cattle cyst fluids, 10 times more concentrated in infertile human hydatid cyst fluids and 13 times more concentrated in sera with hydatid patients. On the other hand, alanine and valine concentration in the fertile and infertile cyst fluids were at similar level with the exception that valine level in fertile cyst fluids was 12 times more concentrated in infertile human cyst fluids. The levels of tyrosine, citrulline, leucine, isoleucine and lysine amino acids in fertile and infertile hydatid cyst fluids were similar. Our findings with respect to fertile and infertile cysts fluids showed that free amino acids concentrations in cyst fluids were significantly, higher in sera from patients with hydatid cyst. Total amount of free amino acids content in fertile and infertile cyst fluids was three to eight times higher from that of human sera with hydatid patients.

Amino Acids↗
PubMed2003

Effect of two formulations of benzimidazole carbamates on the viability of cysts of Echinococcus granulosus in vivo.

Two different preparations, solution and suspension, of three benzimidazole carbamate drugs, mebendazole, albendazole and ricobendazole, were compared by analyzing their in vivo activity against Echinococcus granulosus cysts in a mouse model. Polyvinylpyrrolidone was used for the elaboration of drug solutions and these formulations manifested better results in terms of reduction of number of viable hydatid cysts in mice than the reference drug suspensions. The effect was more prominent on mebendazole-treated mice, at doses of 25-50 mg/kg. There was a correlation between ED50 and pharmacokinetical parameters of AUC0-infinity and Cmax, showing that a significant improvement on solubility affects the in vivo activity of these drugs.

Albendazole↗
PubMed2005

Echinococcus multlocularis infections of rural, residential and urban foxes (Vulpes vulpes) in the canton of Geneva, Switzerland.

We examined 267 red foxes (Vulpes vulpes) from the canton of Geneva, Switzerland, for intestinal infections with Echinococcus multilocularis. This region is situated in the core area of the endemic range of this zoonotic cestode in Central Europe. Several factors were taken into account and urbanisation level appeared to be the most explicative to describe observed differences. The prevalence decreased significantly from rural and residential areas (prevalence of 52%, CI 43-62%, and 49%, CI 38-59 %, respectively) to the urban area (prevalence of 31%, CI 19-42%). A few juvenile foxes harboured very high burdens up to more than 120,000 worms and were significantly more heavily infected than adults. The intensity of infection decreased from rural and residential areas to the city, suggesting a lower contamination of the urban environment.

Age Factors↗
PubMed2006

Genetic differences between Tunisian camel and sheep strains of the cestode Echinococcus granulosus revealed by SSCP.

Ovine and dromedary Echinococcus granulosus isolates from Tunisia were identified as G1 and G6 strains based on polymorphism of the mitochondrial cytochrome C oxydase CO1. Single strand conformation polymorphism (SSCP) was used in order to examine the genetic variation within and between Tunisian G1 and G6 strains and to estimate the extent of selfing. The dromedary isolates are genetically distinct from sheep isolates (high value of genetic variation between populations: Fst= 0.46). No significant deficiency in heterozygotes was found in sheep isolates, whereas heterozygote deficiency (suggesting selfing) was found in a limited number of camel isolates.

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↗
PubMed2001

A major Echinococcus multilocularis antigen is a mucin-type glycoprotein.

The metacestode of Echinococcus multilocularis is surrounded by a carbohydrate-rich laminated layer, which plays a key role in the establishment of the infection in the mammalian host. A major component of the laminated layer is an antigen referred to as Em2(G11). This highly species-specific antigen has been used for serodiagnoses of alveolar echinococcosis and is suggested to contain carbohydrates as major constituents. The results of this work have shown that immunoaffinity-purified Em2(G11) subjected to size-exclusion chromatography eluted mainly in the void volume, indicating a high molecular weight structure of this antigen. Amino acid analysis revealed a large proportion of threonine and proline residues in Em2(G11). The carbohydrate moiety of the antigen was found to be composed of galactose, N-acetylgalactosamine, and N-acetylglucosamine with a ratio of 2.4:1.0:0.5 as determined by gas-chromatography/mass spectrometry. An isotope tag was introduced to the beta-eliminated glycans, and an integrated mass spectrometric O-glycan profiling and sequencing approach was employed to obtain detailed sequence and linkage information of the unseparated glycoform pool. Novel glycoforms containing mucin-type core Gal1-3GalNAc and branched core structures attached to both serine and threonine residues are described. The data presented reveal that the Em2(G11) antigen is a mucin-type glycosylated protein.

Animals↗
PubMed2003

Alternative mRNAs arising from trans-splicing code for mitochondrial and cytosolic variants of Echinococcus granulosus thioredoxin Glutathione reductase.

Thioredoxin and glutathione systems are the major thiol-dependent redox systems in animal cells. They transfer via the reversible oxidoreduction of thiols the reducing equivalents of NADPH to numerous substrates and substrate reductases and constitute major defenses against oxidative stress. In this study, we cloned from the helminth parasite Echinococcus granulosus two trans-spliced mRNA variants that encode thioredoxin glutathione reductases (TGR). These variants code for mitochondrial and cytosolic selenocysteine-containing isoforms that possess identical glutaredoxin (Grx) and thioredoxin reductase (TR) domains and differ exclusively in their N termini. Western blot analysis of subcellular fractions with specific anti-TGR antibodies showed that TGR is present in both compartments. The biochemical characterization of the native purified TGR suggests that the Grx and TR domains of the enzyme can function either coupled or independently of each other, because the Grx domain can accept electrons from either TR domains or the glutathione system and the TR domains can transfer electrons to either the fused Grx domain or to E. granulosus thioredoxin.

Alternative Splicing↗
PubMed2003

Identification of critical residues of an immunodominant region of Echinococcus granulosus antigen B.

Immune evasion strategies often shape the immunogenicity of parasite components. We recently found that the N-terminal extension of the major subunit of Echinococcus granulosus antigen B (AgB), the causative agent of hydatid disease, concentrates the immunoreactive B cell epitopes of the native molecule. The nature of this immunodominance was analyzed using four monoclonal antibodies (mAbs) defining overlapping epitopes in this region of the AgB molecule. The minimal epitope requirements of these mAbs were determined using phage display peptide libraries. The consensus sequences isolated with the mAbs, and alanine replacement analysis with synthetic peptides mapped the relevant molecular contacts within a short stretch corresponding to residues 17-24 of the AgB major subunit. Substitution of two critical residues within this stretch produced a dramatic loss of antigenicity, as determined by using patient sera. The circular dichroism spectra of the antigen, together with the distribution of the contact residues, suggest that this region adopts an amphipathic alpha-helix structure that clusters the contact residues on its polar side. To provide further insight in the interpretation of the structure activity relationships for this immunoreactive region of E. granulosus AgB, we developed a model for the N-terminal extension of the AgB major subunit, which helps to rationalize our data.

Amino Acid Sequence↗
PubMed2001

Echinococcus multilocularis in carnivores from the Klatovy district of the Czech Republic.

A unique human case of alveolar echinococcosis was described in 1979 from the Klatovy district of the Czech Republic. However, there were no previous epidemiological studies in this area focusing on detection of the source of infection--Echinococcus multilocularis adults producing eggs. During the period June 1997 to April 1999, 29 out of a total of 46 (63.3%) red foxes (Vulpes vulpes) in the Klatovy district and one of four foxes (25.0%) in the Pilsen South district were found to be infected with adult worms of E. multilocularis. No E. multilocularis adults were found in other animals from the Klatovy district (i.e. three specimens of Martes martes, two Martes foina, one Mustela erminea, two Meles meles and one Felis catus f. domestica). An examination of faecal samples from 55 dogs (Canis familiaris) from the Klatovy district resulted in the detection of E. multilocularis DNA in one (1.8%) sample. The present results support the possibility that human alveolar echinococcosis previously described in the Czech Republic had the character of an autochthonous infection. There are also indications of a potential risk of infection to humans.

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↗
PubMed2003

Milbemycin oxime in a new formulation, combined with praziquantel, does not reduce the efficacy of praziquantel against Echinococcus multilocularis in cats.

Twenty European domestic cats were each infected with 15,000 protoscoleces of Echinococcus multilocularis extracted from metacestodes grown in experimentally infected common voles (Microtus arvalis). Sixteen days after infection, ten cats were treated with a broad-spectrum anthelmintic and acaricide comprising praziquantel and milbemycin oxime. Five days later treated and untreated cats were euthanized and the intestine examined for E. multilocularis. Five of ten untreated cats were infected with E. multilocularis with worm burdens ranging from 235 to 1920 worms per cat. No E. multilocularis were recovered from any of the treated cats. This study has demonstrated that this new combination broad spectrum anthelmintic and acaricide for cats is highly efficacious against E. multilocularis and the relevance of this is discussed.

Animals↗
PubMed2005

Hydatidosis in camels (Camelus dromedarius) and their potential role in the epidemiology of Echinococcus granulosus in Iran.

Hydatid cysts were recovered from 35.2% (233/661) of camels (Camelus dromedarius) slaughtered in five different regions of Iran. The degree of prevalence between males (34.4%) and females (36.6%) was not statistically significant. The highest rate of infection (59.3%) was found in the Isfahan region (in the central part of Iran) while the lowest (25.7%) was found in Kerman province. The organ distribution of cysts was 49.4% in lungs alone, 30.0% in both liver and lungs, 14.6% in liver only and 6.0% in other organs. Therefore, the lungs were the predominant sites of the hydatid cyst. The range in the number of cysts was 1-48 in infected animals. The majority of the camels had 1-5 cysts, with 21.9%, 11.6% and 5.6% of infected camels having 6-10, 11-20 and 21 or more cysts respectively. There was a direct relationship between the rate and intensity of infection and host age. The fertility rate of lung cysts (69.7%) was higher than that of liver cysts (58.7%) and other organs (50.0%) whilst the viability rate of protoscoleces of liver fertile cysts (80.3%) was significantly higher than that of lung cysts (55.8%) and other organs (57.1%). The role of camels in the epidemiology of Echinococcus granulosus in Iran is discussed.

Animals↗
PubMed2006

Echinococcus multilocularis--a zoonosis of anthropogenic environments?

Transmission of the fox tapeworm Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is known to depend on various environmental factors which are subject to human influence. Epidemiological data suggest that in most endemic regions anthropogenic landscape changes (e.g. deforestation and agricultural practices) have led to more favourable conditions for the parasite's animal hosts, especially arvicolid rodents, thereby increasing the risk for parasite transmission and human disease. Examples are the conversion of forests or crop fields into meadows and pastures in Europe, China and North America, and overgrazing of natural grassland in central Asia. Other anthropogenic factors include interference with host population densities by wildlife disease control, changing hunting pressure and provision of new habitats, e.g. in urban areas. Domestic dogs may, under certain conditions, get involved in the otherwise largely wildlife-based transmission, and thereby greatly increase the infection pressure to humans. The introduction of neozootic host species may increase transmission, or even initiate the parasite's life-cycle in previously non-endemic regions. Lastly, the parasite itself may be accidentally introduced into non-endemic areas, if suitable host populations are present (e.g. in northern Japan).

Animals↗
PubMed2001

Fertility of the cysts of Echinococcus granulosus in domestic herbivores from Benghazi, Libya, and the reactivity of antigens produced from them.

Unilocular cysts produced by Echinococcus granulosus were recovered from 110 domestic herbivores (60 sheep, 25 cattle, 20 goats and five camels) slaughtered in Benghazi. The proportion of the cysts from the sheep found to be fertile (75%) was higher than that of the cysts from the goats (55%), camels (40%), or cattle (0%). When tested in indirect haemagglutination assays (IHA) with eight sera from human cases of cystic echinococcosis, the fluid from the cattle cysts never gave a positive reaction. Antigens in the fluids collected from sheep or goat cysts did react with the sera, with antigens from each of the two sources giving similar titres with each serum. However, crude somatic antigens (prepared from protoscolices and brood capsules collected from sheep cysts) appeared to be more sensitive for the immunodiagnosis of human cystic echinococcosis than the cyst-fluid antigens.

Animals↗
PubMed1983

The susceptibility of the European red fox (Vulpes vulpes) to infection with Echinococcus granulosus of Australian sheep origin.

A detailed comparative study was made of the development of Echinococcus granulosus of Australia sheep origin in European red foxes (Vulpes vulpes) and dogs. No significant differences in growth, segmentation or maturation of the parasite between dogs or foxes was found, although worm burdens were slightly lower in foxes than in dogs. It is concluded that although the role of foxes in the epidemiology of hydatidosis in Australia may not be significant, foxes should nevertheless be regarded as potential definitive hosts of the Australian strains of E. granulosus.

Animals↗