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PubMed1998

Observations on the Echinococcus granulosus horse strain in Spain.

The Spanish sheep and horse strains of Echinococcus granulosus possess several differential characteristics in their metacestode stage. Cysts from sheep vary widely in size and fertility, but they usually have a thin cyst wall and, when fertile, a whitish hydatid sand formed by brood capsules and protoscoleces. Two types of infections have been observed in horses: one resembling that of sheep, caused by small, non-fertile cysts with a thin wall, and a second type caused by medium to large, always fertile cysts with a thick wall. In this latter case, hydatid sand is always dark brown in color and formed mainly by brood capsules (with almost no free protoscoleces) and abundant calcareous corpuscles. These characteristics of the fertile equine cysts, which were identified in other studies by genetic, biochemical, immunological and physiological criteria as belonging to the horse strain, have not been previously described nor observed in cysts from other host species. It is considered that the horse strain possesses a strong intermediate host specificity.

Animals↗
PubMed1998

Control of Echinococcus granulosus in Cyprus and comparison with other island models.

A control programme directed against Echinococcus granulosus was introduced into the Republic of Cyprus in 1971. In 1974, this was restricted to the areas controlled by the government of the island. The force used in the 'attack' phase included a major dog control programme. This and other measures led to the rapid 'disappearance' of the parasite and control was terminated in 1985. Subsequent studies during 1993-1996 revealed that the parasite was present in 82 (20%) villages in either dogs or food animals or both and control was re-introduced in the 'consolidation' phase with emphasis on the surveillance of E. granulosus in intermediate hosts, animal movement control and treatment of dogs in 'infected' villages. During these surveys, a major difficulty was found to be in determining whether transmission was autocthonus or introduced by animals from the areas not controlled by the government. Evidence was found to suggest the former was the most likely for the infected animals which had been born and reared far from the dividing line in the government-controlled area. A major contribution of this and other island programmes, such as those in Iceland, New Zealand, Tasmania (Australia) and the Falkland Islands, to an understanding of control planning has been the demonstration that it cannot readily be determined when eradication has been achieved and that once the costly 'attack' phase has been converted into the much more cost-effective 'consolidation' phase this must be maintained indefinitely in that phase if there is cross-border transmission as is likely to be the case in all Continental control programmes.

Animals↗
PubMed1998

Random amplified polymorphic DNA for the specific detection of bubaline Echinococcus granulosus by hybridization assay.

The polymerase chain reaction (PCR) method to randomly amplify polymorphic DNA (RAPD) was used to differentiate the bubaline and bovine strains of Echinococcus granulosus and buffalo host DNA. Four random oligonucleotide primers of 10-11 mer were analyzed for their ability to direct the amplification of polymorphic DNA fragments from parasites and bovine DNA. Significant DNA polymorphism was observed between the E. granulosus isolates. A selectively amplified DNA fragment 0.9 kilobase (kb) from E. granulosus buffalo isolate by primer AP2 (5'-TGCCGAGCTG-3') was reamplified and used as a DIG-labelled DNA probe. Dot-blot hybridization of total genomic DNA differentiated buffalo E. granulosus isolate from bovine isolate and bubaline host DNA with no detectable cross-hybridization signal.

Animals↗
PubMed1999

Detection of Echinococcus multilocularis in foxes in The Netherlands.

Echinococcus multilocularis was demonstrated in 5 out of 272 foxes in The Netherlands close to the border with Germany and Belgium. Besides microscopic examination of mucosal scrapings, two different PCR assays were used based on the detection of E. multilocularis DNA in colon content. Two distinct areas in The Netherlands were positive for E. multilocularis. Two positive foxes were found in the northern province of Groningen and three positive foxes were found in the southern province of Limburg. Both PCR assays detected more positive foxes compared to microscopic examination of the intestinal content. This is the first report of E. multilocularis in foxes occurring in The Netherlands.

Animals↗
PubMed1999

Some studies on the growth and development of Echinococcus granulosus, camel origin in experimentally infected dogs.

The development of Echinococcus granulosus of camel subspecies in 35 experimentally infected dogs was studied at 3, 7, 10, 13, 18, 23, 35 and 56 days post-infection (d.p.i.). The morphological characteristics of each developmental stage is studied and discussed. Morphological characters included number, total length, shape, arrangement of rosteller hooks and blade length to total length percentage (B1/T1%). In addition, total worm length, scolex, suckers, rostellum, neck and segments were measured and described. Other useful characters are considered to be the position of common genital pore, number and distribution of testes, uterus, shape of ovary and vitelline glands. Generally, the results indicated that the segmentation first appears at 18 d.p.i. Moreover, male and female genitalia could be detected at the same period. However, completely developed genitalia appeared at 56 d.p.i. Histological examination of the small intestine of experimentally infected dogs revealed that the parasites were found in distended and thin wall crypts of Liberkuhn at the periods of 3.7 and 10 d.p.i, while the parasite scoleces were found embeded in the mucosa at the periods of 13, 18 and 23 d.p.i. No significant pathological changes were encountered in both infected and control dogs. The data presented here are the first report of strobilar development of E. granulosus of camel origin in experimentally infected dogs.

Animals↗
PubMed1999

Prevalence of Echinococcus granulosus infection in stray dogs and herbivores in Shiraz, Iran.

One hundred and five stray male and female dogs in different age groups were autopsied and their small intestines examined for Echinococcus granulosus. Thirty eight dogs (36.19%) harbored two-to-several thousand E. granulosus in their intestinal content. The prevalence rate was higher in males (44.83%) than in females (25.53%). Livers and lungs of 3245 sheep, 2576 goats, 756 cattle and 25 buffaloes slaughtered for meat purposes at different Shiraz slaughterhouses were examined for hydatidosis: 2.09% of livers and 2.68% of lungs of sheep, 2.17% and 2.36% of goats, 4.49% and 6.48% of cattle and 4% and 8% of buffaloes, respectively, were infected.

Animals↗
PubMed2000

Rate of infection and of reinfection by Echinococcus granulosus in rural dogs of the province of Rio Negro, Argentina.

Hydatidosis (cystic echinococcosis) constitutes a serious public health problem in the Province of Rio Negro, Argentina. In the present work it was intended to evaluate the prevalence of the canine echinococcosis in rural areas of the Province of Rio Negro and studied the reinfection rate in dogs after treatment with Praziquantel during the period 1980-1997. A total of 496 dogs were studied in 18 canine concentrations in order to establish the initial prevalence rate which was 42.3%. From 1980 onward dogs should have been systematically treated with anthelmintic every 2 months in rural areas and every 6 months in urban areas. We estimated that approximately 65% of dogs were treated. To determine the reinfection rate, 476 dogs (1984) and 598 dogs (1996) were studied after anthelmintic treatment during two sequential time periods (0-45; 46-90 days). In both cases treated animals were compared with untreated dogs. Prevalences were 3.5%, 6.7% and 21.3% in 1984 and 0.8%, 4.0% and 10.0% in 1996. For the purpose of surveillance a total number of 21,444 dogs were studied during 18 years. Prevalence of Echinococcus granulosus decreased significantly in the first year from 42.3% to 6.1%.

Animals↗
PubMed1998

Purine metabolism in Echinococcus multilocularis.

The activities of the enzymes in Echinococcus multilocularis metacestodes involved in purine salvage were studied by HPLC. As in most parasites, this cestode relies entirely on salvage of preformed bases and nucleosides for its purine requirement. Therefore, these enzymes may be targets for drugs in the chemotherapeutic treatment of diseases caused by this parasite. The animals used in this study were gerbils (Meriones unguiculatus). Enzyme activities from sera and hepatic tissue in control and infected animals were similar with the exception of adenine phosphoribosyltransferase which showed an activity 4-fold greater in the serum from control than in serum from infected animals. In the parasite, adenine and hypoxanthine-guanine phosphoribosyltransferases and adenosine deaminase had the highest activities. Therefore, in E. multilocularis metacestodes, this pathway seems to be important for the parasite's metabolism.

Adenine Phosphoribosyltransferase↗
PubMedDate not supplied

Spinal cord compression due to costal Echinococcus multilocularis.

We present computerized tomography (CT) and magnetic resonance imaging (MRI) findings of a costal hydatid cyst (Echinococcus multilocularis) causing spinal cord compression. The hydatid disease was proved histologically. MRI was not only very useful for determining the spinal extension of the disease by its multiplanar imaging capability, but also gave important information about the texture of the cyst, thus aiding the preoperative diagnosis.

Adult↗
PubMed1999

Coproantigen survey for Echinococcus multilocularis prevalence of red foxes in Hokkaido, Japan.

An epidemiological survey was conducted on the seasonal variation of Echinococcus multilocularis prevalence in red foxes from 1997 to 1998, using a monoclonal antibody-based detection of the tapeworm coproantigen. Thirty-six breeding dens of reproductive fox families were identified in the endemic area of Koshimizu, eastern Hokkaido, Japan. Fecal samples from each site were examined by coproantigen detection assay and fecal egg examination. Whereas the prevalence of coproantigen positive feces showed no seasonal fluctuation (51.6-66.7%), variation was found in the prevalence of egg positive feces in which a higher prevalence was observed in the summer and winter (31.1 and 38.7%) than spring and autumn (13.3 and 13.5%). Significant differences were observed between juveniles and adult foxes in both examinations. Samples from juvenile foxes gave higher coproantigen positive results and taeniid egg intensity. Those results suggest more juveniles infected with the cestode than adults in the same period. The practical use of coproantigen assay as a survey tool and factors which affect the prevalence and host age-related difference are discussed.

Animals↗
PubMed2003

Genomic structure and expression of a gene coding for a new fatty acid binding protein from Echinococcus granulosus.

This work describes a new gene coding for a fatty acid binding protein (FABP) in the parasite Echinococcus granulosus, named EgFABP2. The complete gene structure, including the promoter sequence, is reported. The genomic coding domain organisation of the previously reported E. granulosus FABP gene (EgFABP1) has been also determined. The corresponding polypeptide chains share 76% of identical residues and an overall 96% of similarity. The two EgFABPs present the highest amino acid homologies with the mammalian FABP subfamily containing heart-FABPs (H-FABPs). The coding sequences of both genes are interrupted by a single intron located in the position of the third intron reported for vertebrate FABP genes. Both genes are expressed in the protoscolex stage of the parasite. The promoter region of EgFABP2 presents several consensus putative cis-acting elements found in other members of the family, suggesting interesting possible mechanisms involved in the host-parasite adaptation.

Amino Acid Sequence↗
PubMed2002

Culture of Echinococcus multilocularis metacestodes: an alternative to animal use.

This article reviews the use of an in vitro culture model for the maintenance and proliferation of Echinococcus multilocularis metacestodes and the formation of protoscoleces. This model has been used to identify and characterize parasite molecules involved in host-parasite interactions, and is a suitable tool to perform in vitro drug-screening assays. The development of a simple and easy-to-handle assay to determine the effects of drugs on parasite viability, without the need for time-consuming animal experimentation, has opened the way for larger-scale in vitro drug screening.

Animal Testing Alternatives↗
PubMed2002

Several strains of Echinococcus granulosus infect livestock and humans in Argentina.

Mitochondrial cytochrome oxidase subunit 1 (CO1) sequencing, Southern blot of a repetitive DNA element and single strand conformation polymorphism of the 5' non-transcribed region of the cytosolic malate dehydrogenase (MDH) gene were used to determine the extent and distribution of Echinococcus granulosus genetic variation in Argentina. Five distinct strains of E. granulosus were shown to exist in the country. The common sheep, Tasmanian sheep, cattle and camel strains were identified in humans. Unlike the situation found in other countries, where the common sheep strain is the major source of human contamination, the Tasmanian sheep and camel strains produced a significant number of human infections in some regions of Argentina. This is the first report of cattle strain in humans in South America. Goats could be the natural intermediate host of the camel strain, which was not identified in humans from other regions so far. More than one genotype was identified in the same geographic area. These findings may have important consequences for human health and the control of hydatid disease. Within-strain differences were also observed, showing the potential of variation of E. granulosus.

5' Flanking Region↗
PubMed2003

Isolation of polymorphic microsatellite loci from the tapeworm Echinococcus multilocularis.

Two microsatellites were isolated from a genomic library of Echinococcus multilocularis. The microsatellites, designated EMms1 and EMms2, consist of tandem repeats of CAC-trinucleotide unit. Southern blot hybridization suggests that each of them is a single locus. Using fox-derived wild tapeworms (N=104), PCR-amplification of microsatellites was performed to assess the usefulness of these loci. We found four alleles of EMms1 and two alleles of EMms2. The heterozygosities observed were 10.6% in EMms1 and 7.7% in EMms2. The result suggests that both selfing and outcrossing occur in the adult stage of E. multilocularis.

Animals↗
PubMed2003

The crystal structure of Echinococcus granulosus fatty-acid-binding protein 1.

We describe the 1.6 A crystal structure of the fatty-acid-binding protein EgFABP1 from the parasitic platyhelminth Echinococcus granulosus. E. granulosus causes hydatid disease, which is a major zoonosis. EgFABP1 has been implicated in the acquisition, storage, and transport of lipids, and may be important to the organism since it is incapable of synthesising most of its lipids de novo. Moreover, EgFABP1 is a promising candidate for a vaccine against hydatid disease. The crystal structure reveals that EgFABP1 has the expected 10-stranded beta-barrel fold typical of the family of intracellular lipid-binding proteins, and that it is structurally most similar to P2 myelin protein. We describe the comparison of the crystal structure of EgFABP1 with these proteins and with an older homology model for EgFABP1. The electron density reveals the presence of a bound ligand inside the cavity, which we have interpreted as palmitic acid. The carboxylate group of the fatty acid interacts with the protein's P2 motif, consisting of a conserved triad R em leader R-x-Y. The hydrophobic tail of the ligand assumes a fairly flat, U-shaped conformation and has relatively few interactions with the protein.We discuss some of the structural implications of the crystal structure of EgFABP1 for related platyhelminthic FABPs.

Amino Acid Motifs↗
PubMed1997

Echinococcus multilocularis: mouse strain difference in hydatid development.

Female mice of nine inbred strains (A, AKR, BALB/c, C3H, C57BL/6, C57BL/10, CBA, DBA/1 and DBA/2) and H-2 congenic B10.D2, at 9-10 weeks of age, were infected with larval Echinococcus multilocularis by trans-portal injection of hydatid homogenate. Parasitized livers were histologically examined 9 or 13 weeks after infection. Hydatid development was quite different among mouse strains. Multivesiculation was prominent in C57BL/10, DBA/1, C57BL/6 and BALB/c. Protoscoleces were well developed in DBA/2, AKR, DBA/1 and CBA. H-2 congenic B10.D2, which has the background genes of C57BL/10 except for the H-2d gene of DBA/2, resembled C57BL/10 in prohibiting the development of protoscoleces. These data suggest that the qualitative difference in hydatid development may be regulated by non-H-2 gene(s).

Animals↗
PubMed1997

Echinococcus granulosus: characterization of the Spanish strains using in vitro vesicular development.

Differences in in vitro vesicular development (microcyst formation) in three Spanish strains of Echinococcus granulosus (sheep-cattle, horse and pig-goat) are reported. Microcyst formation occurred in 19-37 days (sheep strain), 9-18 days (pig strain) and 35-47 days (horse strain). Comparing these results with those from human samples (microcyst formation in 24-38 days), it is possible to consider the sheep strain as the most likely source of human infections in Spain.

Animals↗
PubMed1977

Studies on the mechanism of lysis of Echinococcus granulosus protoscoleces incubated in normal serum.

Brood capsules were obtained from freshly collected cysts of equine and ovine strains of Echinococcus granulosus. Protoscoleces were freed from brood capsules either by mechanical disruption or pepsin-HCI digestion. Preparations of protoscoleces studied included: mechanically released protoscoleces without further treatment, or incubated either in HCI pH 2.0 or in evaginating solution (containing Na taurocholate) for 24 h; pepsin-HCI released protoscoleces without further treatment or incubated in evaginating solution for 24 h or 7 days. Half of each preparation of ovine protoscoleces was fixed in absolute methanol. All fresh preparations of protoscoleces lysed rapidly when incubated in normal human serum. Studies with a fluorescein isothiocyanate (FITC) labelled sheep anti-human C3 antiserum revealed the presence of C3 on the surface of lysing protoscoleces. Antibody could not be detected on the surface of any of the preparations of fresh or methanol-fixed protoscoleces using direct or indirect fluorescent antibody tests suggesting that the classical pathway of complement activation was not involved in the lytic process. Strong evidence for lysis by the alternate pathway of complement activation was the lysis of protoscoleces which had been treated with pepsin-HCI and lysis of protoscoleces in guinea-pig serum deficient in C4 component of complement.

Animals↗