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At least 19 recordsLinked to original sources
PubMed2001

Infection induces antibodies against the cercarial secretions, but not against the cercarial elastases of Schistosoma mansoni, Schistosoma haematobium, Schistosoma japonicum and Trichobilharzia ocellata.

Cercarial secretions from different species of the parasite Schistosoma and from Trichobilharzia ocellata contain a proteolytic activity, cercarial elastase, which was demonstrated by a 30 kDa band in gelatin gels. Sera of patients infected with Schistosoma mansoni, Schistosoma haematobium or Schistosoma japonicum contain immunoglobulin G which react in ELISA with cercarial secretions from all schistosomes and cross-react among the different parasite species. In Western blots, however, infection sera from patients, as well as heavily infected mice or rabbits, did not react with a 30-kDa protein. Moreover, when sections from infected snails (Biomphalaria, Bulinus and Lymnaea) were analysed by immunofluorescence using the same infection sera, only the tegument of the developing cercariae was recognized, but not the acetabular glands. In contrast, when antisera against purified cercarial elastase from either S. mansoni or S. haematobium were tested with sections of infected Biomphalaria or Bulinus, fluorescence was strong in the preacetabular glands of the cercariae of either species, but undetectable with the tegument. Cross-reactivity of both antisera extended to T. ocellata-infected Lymnaea, but not to S. japonicum-infected Oncomelania. In conclusion, although immunization with purified cercarial elastase results in antibody production, the enzyme does not induce an apparent antibody response following natural infection.

Animals↗
PubMed2006

A revision of the interrelationships of Schistosoma including the recently described Schistosoma guineensis.

In light of the recently described human schistosome Schistosoma guineensis and recent phylogenetic studies of the genus Schistosoma, a revision of the interrelationships of the members of this genus is needed. This paper adds to previous phylogenetic studies on the family Schistosomatidae and offers the most up to date and robust phylogeny of the group based on complete small and large nuclear subunit rRNA genes and partial mitochondrial cox1, incorporating most of the 21 species of Schistosoma. Our findings show that the group retains the same topology as that resolved in previous studies except Schistosoma margrebowiei was resolved as the sister taxon to all others in the Schistosoma haematobium species group and S. guineensis was placed as sister species to both Schistosoma bovis and Schistosoma curassoni. The S. haematobium species group contains eight species of which many are of significant medical and veterinary importance. Additionally, many of these species have been shown to hybridise both in the wild and experimentally, making the correct identification and recognition of species very important. A pairwise comparison of cox1 among Schistosoma species suggests this gene alone would fail as a reliable barcode for species identification. Phylogenetic results clearly treat Schistosoma intercalatum and S. guineensis as separate taxa with each more closely related evolutionarily to S. haematobium than to each other. The study also highlights the problems associated with wrongly attributed sequences on public databases such as GenBank.

Africa South of the Sahara↗
PubMed2004

CpG island methylation in Schistosoma- and non-Schistosoma-associated bladder cancer.

Urothelial carcinomas (TCC) constitute the vast majority of bladder cancers in most of the world. On the other hand, squamous cell bladder carcinoma, a rare subtype in the Western world, is a common subtype in areas with endemic Schistosoma infection. Although schistosomal infection has been reported to influence DNA methylation, the pattern and extent of CpG island hypermethylation in squamous cell carcinomas remain unknown. In this study, we used methylation-specific PCR to characterize 12 cancer-related genes in 41 bladder cancer samples from Egypt (31 squamous cell carcinomas (SCC), 21 of them associated with Schistosoma and 10 TCC, five of which were Schistosoma-associated). The genes analyzed included E-cadherin, DAP-Kinase, O6MGMT, p14, p15, p16, FHIT, APC, RASSF1A, GSTP1, RARbeta and p73. Methylation of at least one gene was detected in all squamous cell tumors except two, and 45% of samples had at least three methylated genes. The average methylation index was 0.24, corresponding to three of the 12 analyzed genes. Schistosoma-associated tumors had more genes methylated than non-Schistosoma tumors (average MI: 0.29 vs 0.14) (P = 0.027). Although the extent of methylation in TCC (average MI: 0.16) was lower than in squamous cell carcinomas (SCC), the overall profile of methylation was similar, with Schistosoma-associated cases having a higher methylation index. Our results suggest that schistosomal involvement associates with a greater degree of epigenetic changes in the bladder epithelium.

Acid Anhydride Hydrolases↗
PubMed2006

The complete mitochondrial genomes of Schistosoma haematobium and Schistosoma spindale and the evolutionary history of mitochondrial genome changes among parasitic flatworms.

Complete mitochondrial genome sequences for the schistosomes Schistosoma haematobium and Schistosoma. spindale have been characterized. S. haematobium is the causative agent of urinary schistosomiasis in humans and S. spindale uses ruminants as its definitive host; both are transmitted by freshwater snail intermediate hosts. Results confirm a major gene order rearrangement among schistosomes in all traditional Schistosoma species groups other than Schistosoma japonicum; i.e., species groups S. mansoni, S. haematobium, and S. indicum. These data lend support to the 'out of Asia' (East and Southeast Asia) hypothesis for Schistosoma. The gene order change involves translocation of atp6-nad2-trnA and a rearrangement of nad3-nad1 relative to other parasitic flatworm mt genomes so far sequenced. Gene order and tRNA secondary structure changes (loss and acquisition of the DHU and/or TPsiC arms of trnC, trnF, and trnR) between mitochondrial genomes of these and other (digenean and cestode) flatworms were inferred by character mapping onto a phylogeny estimated from nuclear small subunit rRNA gene sequences of these same species, in order to find additional rare genomic changes suitable as synapomorphies. Denser and wider taxon sampling of mt genomes across the Platyhelminthes will validate these putative characters.

Animals↗
PubMed1988

Schistosoma malayensis n. sp.: a Schistosoma japonicum-complex schistosome from Peninsular Malaysia.

Schistosoma malayensis n. sp., a member of the Schistosoma japonicum complex is described from Rattus muelleri in Peninsular Malaysia and 2 strains are characterized. The only morphological differences noted among adults from natural hosts were that S. malayensis are in general smaller than S. mekongi and S. japonicum. But these differences may be the result of host-induced variations and therefore are of little taxonomic value. To minimize the effects of host-induced variations, adult worms recovered from laboratory mice with similar worm burdens at 50-56 days postinfection were compared. These comparisons revealed only minor morphometric differences among these 3 species. Schistosoma malayensis eggs from naturally and experimentally infected hosts are most similar to those of S. mekongi, with eggs of both species being, in general, smaller than those of S. japonicum. The egg index for S. malayensis is usually higher than for S. japonicum and lower than for S. mekongi. Differences were noted in the developmental rates in mice for 2 isolates of S. malayensis, S. mekongi, and S. japonicum (Philippine strain), but relatively large differences observed between isolates of S. malayensis indicate that, in this case, the developmental rate is not a useful taxonomic character. Schistosoma malayensis is erected principally on the basis of differences, reported elsewhere, in the life histories and in the electrophoretic migration patterns of isoenzymes of adult worms as compared to S. mekongi and S. japonicum. These comparisons indicate that S. malayensis is more closely related to S. mekongi than to S. japonicum.

Animals↗
PubMed1995

Worm development in hamsters infected with unisex and cross-mated Schistosoma mansoni and Schistosoma haematobium.

Schistosoma mansoni and Schistosoma haematobium coexist in Egypt and in other areas in Africa, and people frequently are infected with parasites of both species. The effects of the interactions between worms of both sexes of the 2 species on development and egg laying were evaluated in vivo by infecting hamsters with cercariae from Biomphalaria alexandrina and Bulinus truncatus snails infected with single miracidia. In hamsters with unisex infections, male worms of both species were small. Schistosoma mansoni females were stunted and partially mature but did not contain eggs. Schistosoma haematobium females, though stunted, sometimes contained and laid small eggs, which were deposited in the liver, but few of which contained motile embryos. This suggests that unisexual infection with S. haematobium female worms produces a risk for liver damage due to egg deposition in tissues. Both S. mansoni and S. haematobium females that mated with males of the heterologous species were significantly larger than females from unisexual infections; they were sexually mature and possessed eggs in the uterus. The eggs in the liver homogenates of cross-specific infected hamsters contained fully developed miracidia that hatched in filtered pond water.

Animals↗
PubMed1997

A recombinant protein from Schistosoma mansoni useful for the detection of S. mansoni and Schistosoma haematobium antibodies.

A recombinant Schistosoma mansoni protein has been identified as a useful antigen for the detection of S. mansoni and Schistosoma haematobium antibodies. The purified recombinant protein, Sm22.3, was assayed using an enzyme-linked immunosorbent assay format against a battery of 491 well defined sera, including S. mansoni, S. haematobium, and Schistosoma japonicum infection sera, normal human sera, sera from 9 other parasitic infections, and sera from 2 additional infections. The sensitivity for detecting S. mansoni and S. haematobium infections with this single recombinant protein is 80.1%. The specificity is 94.8%. However, 15 of the 16 cross-reactive sera are malaria infection sera, and we have data suggesting that these malaria sera are actually recognizing an epitope on the vector-derived 6Xhistidine tag of recombinant Sm22.3. If this is the case, then, the actual specificity of the assay is 99.6%.

Animals↗
PubMed1997

[Infection by Schistosoma intercalatum and probable hybridization with Schistosoma haematobium in East Africa. Report of a case].

It is reported the infection due to Schistosoma intercalatum and the probable hybridization with Schistosoma haematobium in a patient from the eastern region of Africa, where it has not been demonstrated before. The main clinical manifestations were abdominal pain and diarrhea with blood. The diagnosis was possible thanks to the finding in the microscopic examination of the characteristic eggs of Schistosoma intercalatum in faeces and urine by the modified technique of Ziehl-Neelsen.

Adult↗
PubMed2005

Combined Schistosoma mansoni and Schistosoma haematobium infection.

An imported case of combined Schistosoma mansoni and Schistosoma haematobium infection occurring in Liberia is reported. A young girl of 15 years, who had recently returned from the neighbouring country of Guinea, presented with 04 months history of passing blood in stools. Schistosoma mansoni ova were found in stool and Schistosoma haematobium ova in urine. She was treated with tablet praziquantel. She became symptom-free in four weeks and the number of ova passed in stool and urine decreased.

Adolescent↗
PubMed1999

Schistosoma TOR (trispanning orphan receptor), a novel, antigenic surface receptor of the blood-dwelling, Schistosoma parasite.

Sh-TOR is a novel, putative three transmembrane domain receptor of Schistosoma haematobium, which has no extensive homology to any other known protein. The 0.86 kb open reading frame was found to encode a novel protein, 286 amino acids long and of 32 kDa. It was shown that Sh-TOR can be phosphorylated on tyrosine and the protein sequence reveals a long cytoplasmic tail with several consensus phosphorylation sites for enzymes which characteristically associate with membrane receptors. The proposed topology of Sh-TOR, based on antibody recognition of transfected Sh-TOR, predicts that the amino terminus is extracellular and the carboxyl terminus intracellular. Sh-TOR is a non-glycosylated protein found in the surface tegumental plasma membrane, and tegumental surface pits of adult schistosomes. The 1.35 kb transcript was most highly expressed in the larval stage, which is more susceptible to immune attack. A TOR homologue from Schistosoma mansoni is also described. A homologue from Trypanosoma cruzi, another human parasite was also isolated, but not from the free-living nematode Caenorhabditis elegans. Recombinant Sh-TOR is specifically recognised by a passively protective serum, from baboons vaccinated with irradiated Schistosoma parasite. Together with its surface location, this means that Sh-TOR is also a potential vaccine candidate molecule.

Amino Acid Sequence↗
PubMed1979

Susceptibility of Iraqi fresh water snails to infection with Schistosoma haematobium and Schistosoma mansoni Egyptian strains.

A great number of Egyptian workers and farmers are seeking settlement in Iraq and some of them proved to have either Schistosoma Haematobium (S.h.) or Schistosoma mansoni (S.m) or even mixed infection. Besides, there is the possibility that some of the Iraqi fresh water snails may prove to be susceptible to infection by one or both of the Schistosoma Egyptian strains. The present study deals with investigations on the susceptibility of Iraqi B. truncatus, Gyranaulus ehrenbergi, Physa c.f. fontinalis, Lymnea lagetis, Melanoides tuberculata and Melanopsis nodes by these parasites. Egyptian S. haematobium but not Egyptian S. mansoni infect Iraqi B. truncatus and both proved to be unable to infect any of the other snails included in the study. Yet, the number of cercariae shedded by B. truncatus snails infected with the Egyptian S. haematobium strain, was much less that the number of cercariae shedded by these snails when infected with the Iraqi S. Haematobium strain.

Animals↗
PubMed2002

Schistosoma ovuncatum n. sp. (Digenea: Schistosomatidae) from northwest Thailand and the historical biogeography of Southeast Asian Schistosoma Weinland, 1858.

Schistosoma sinensium Bao, 1958 was first isolated from an unidentified snail in Sichuan Province, PR China. This species was apparently rediscovered in Chiang Mai Province, northwest Thailand (Baidikul et al., 1984); the definitive host was the rat Rattus rattus and the intermediate host was the snail Tricula bollingi. In this paper S. sinensium is rediscovered in Sichuan Province and compared with worms recovered from experimentally infected mice, which had been exposed to cercariae shed by T. bollingi from Chiang Mai. Evidence is presented suggesting that the schistosome collected by Baidikul was not S. sinensium and that a new species is involved. The new species, named Schistosoma ovuncatum (etymology: ovum (egg) + uncatus (hooked)), is described and compared with related taxa. All previous papers on the Thai schistosome have used worms recovered from field-collected rodents only; this is the first account in which the life-cycle has been completed in the laboratory, using cercariae shed by T. bollingi, and the resulting worms described. S. ovuncatum differs from S. sinensium in terms of size and shape of body and egg, number of testes, size of ovary, length of vitellarium, intermediate host and biogeographical distribution. The relationships of the two taxa and their position with respect to the Schistosoma indicum- and S. japonicum-groups are discussed. The implications of the findings for the evolution of human schistosomiasis in the region are also commented upon.

Animals↗
PubMed2002

Schistosoma mansoni and Schistosoma haematobium: identification and characterization of glycoconjugate antigens in the hemolymph of infected vector snails.

Two carbohydrate epitopes were identified by monoclonal antibodies (KCS and E2) and characterized with respect to their immunoreactivity, monosaccharide structure, and location. Immunofluorescence demonstrated the presence of both epitopes on the surfaces of sporocysts, cercariae, and miracidia of Schistosoma mansoni, Schistosoma haematobium, and Schistosoma japonicum. However, spatial distribution and density of expression varied among species and developmental stages, and neither epitope was detectable on adult worm surfaces. Both glycans were found in the hemolymph of infected, but not uninfected, intermediate snail hosts. The presence of epitopes in hemolymph, as well as in schistosome eggs, is species-specific for KCS, recognizing only S. mansoni, and partly specific for E2, which reacted predominantly with S. haematobium. Immunoaffinity purification of target antigens for KCS and E2 from hemolymph of infected Biomphalaria and Bulinus, respectively, followed by carbohydrate composition analysis revealed a high content of fucose in both glycans. Methylation analysis demonstrated exclusively terminal fucose for the target antigen of KCS and terminal as well as internal fucose for the one of E2. Removal of terminal fucose abolished reactivity with both monoclonal antibodies. Both glycans are different from previously characterized schistosome carbohydrates. Their biological function(s) remain to be defined.

Animals↗