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PubMed1998

Use of monoclonal antibodies prepared against Schistosoma mansoni hatching fluid antigens for demonstration of Schistosoma haematobium circulating egg antigens in urine.

A panel of 17 monoclonal antibodies (MAbs) against Schistosoma soluble egg antigens (SEAs) was produced from BALB/c mice immunized with antigens secreted/excreted by Schistosoma mansoni eggs. In this study, we demonstrate that 16 MAbs were reactive with S. haematobium SEA in addition to S. mansoni SEA. The MAbs were tested as potential immunodiagnostic reagents in a homologous sandwich ELISA format to detect circulating soluble egg antigens (CSEAs) in serum and urine samples of S. mansoni- or S. haematobium-infected individuals. When samples of S. mansoni-infected individuals were tested, none of these MAbs performed as good as the previously described S. mansoni-specific 114-5B1-A and 114-4D12-A MAbs. However, 11 MAbs (of the IgM isotype) detected CSEA in urine samples of S. haematobium-infected individuals. Three MAbs, 290-2E6-A, 291-3D5-A, and 291-5D5-A, were selected for a pilot study with 47 urine samples of S. haematobium-infected individuals from Kenya. The CSEA levels detected with each of these ELISAs showed a significant correlation with urinary egg counts (Spearman rho > 0.37, P < 0.01) and with each other (Spearman rho > 0.74, P < 0.001). Based on the 92% specificity and 90% sensitivity of the assay, the ELISA using MAb 290-2E6-A was found to be the most promising assay for immunodiagnosis of S. haematobium infections.

Animals↗
PubMed1999

Schistosoma japonicum is less sensitive to cyclosporin A in vivo than Schistosoma mansoni.

We compared the toxic effects of cyclosporin A (CsA) on postmigratory immature Schistosoma mansoni and Schistosoma japonicum in mice. For each species, CsA was administered either relatively early or late during development. Exposure of 20-day-old S. mansoni to 1 subcutaneous dose of CsA (50 mg/kg) reduced the worm burden by 45% and induced herniae and/or boli of the gut in 32% of perfusable worms. These results agree with previous reports. In addition, CsA induced a marked liver shift (37% of total worm number). For S. japonicum, CsA was administered at 11 days postinfection (PI) because this species migrates more quickly. Killing of worms and damage to the gut were not observed, and only a slight liver shift occurred. Similarly, these effects were not recorded when CsA was administered at the later times of 34 days PI for S. mansoni and 17 days PI for S. japonicum. For both species, CsA stunted worms, affecting both sexes early PI but only females late PI. In conclusion, immature worms of S. japonicum are less sensitive than S. mansoni to CsA. Also, S. mansoni displays marked age-dependent differences in its sensitivity to CsA.

Age Factors↗
PubMed1999

[Immunocytochemical localization of two facilitated glucose transporters of Schistosoma mansoni in the tegument of Schistosoma japonicum].

AIM: To observe the distribution of Schistosoma mansoni glucose transport proteins, SGTP1 and SGTP4, in the tegument of Schistosoma japonicum. METHODS: The rapidly frozen fixation technique and ultracryomicrotomy were adopted for preparing ultrathin cryosections of S. japonicum. Anti-SGTP1 and anti-SGTP4 antibodies were used to localize the corresponding antigens in the tegument of adult S. japonicum by immunocytochemical technique. RESULTS: SGTP1 was localized on the basal membrane of the tegument and its infoldings, SGTP4 was localized on the apical membrane of the tegument and its invaginations of S. japonicum. CONCLUSION: The same localization for SGTP 1 and SGTP4 in the tegument of S. japonicum and S. mansoni exhibited apparent homology between SGTPs of the two schistosomes.

Animals↗
PubMed2005

Hybridization of Schistosoma mansoni and Schistosoma japonicum in mice.

Crossing experiments in mice with two human species of Schistosoma japonicum (Taiwan strain) and Schistosoma mansoni (Puerto Rican strain) were performed. The hybrid miracidia from the cross between female S. japonicum and male S. mansoni infected both Biophalaria glabrata and Oncomalania h. chiui. However, those from the reciprocal crossing could infect only B. glabrata. B. glabrata infected with hybrid miracidia of female S. mansoni x male S. japonicum survived up to 30 days while those infected with miracidia of S. mansoni remained alive for more than 100 days after the first shedding of cercariae. Relatively few hybrid eggs reached maturity either in tissues or in the feces of infected mice. A low percentage of F1 eggs hatched and the infectivity of F1 miracida was also low. Morphology and behavior of hybrid eggs, miracidia, cercariae, and adults were similar to the maternal species. The daily egg production of the hybrid worm pair was less than that of the normal one. The observations in the present study may be attributed to the maternal effects. However, the phenomenon of parthenogenesis in schistosomes cannot be confirmed.

Animals↗
PubMed1982

Granuloma formation around exogenous eggs of Schistosoma mansoni and Schistosoma japonicum in mice.

Hepatic granulomata which were qualitatively and quantitatively similar to those seen in infections established with cercariae were induced by surgical injection of exogenous eggs of Schistosoma mansoni and Schistosoma japonicum via the mesenteric veins of previously unexposed albino mice. Thereafter, their comparative histopathologic studies were made. The maximum mean sizes of granulomata were attained on Day 32 with viable eggs of these parasite species. Although S. mansoni eggs produced significantly larger lesions (368.4 +/- 21.5 microns) than eggs of S. japonicum (205.8 +/- 18.6 microns) at the peak period, the difference in the mean granulomal size showed no correlation with either the time of onset or the severity of pathologic changes produced. Thus, eggs of S. japonicum with smaller granulomata, evoked pathologic changes which were earlier in onset and more severe than those produced by the same quantity of S. mansoni eggs. Since the most obvious variables (the quantity of eggs, the sequence of their arrival in the liver, the timing of observation, and the strain of experimental animals) were controlled, it was concluded that the most severe and fatal effects produced by eggs of S. japonicum, as previously suggested, are largely due to differences in the cytotoxic and antigenic peculiarities of this species.

Animals↗
PubMed1983

Fluorescent histochemistry of acid proteases in adult Schistosoma mansoni and Schistosoma japonicum.

The acid proteases, cathepsin B, dipeptidyl aminopeptidase I and II were demonstrated by fluorescent histochemistry in adult Schistosoma mansoni and Schistosoma japonicum. Alanyl- and leucine-aminopeptidase activities were not observed. The substrates consisted of 4-methoxy-beta-naphthylamide derivatives coupled to the fluorescent molecule, 5-nitrosalicylaldehyde. Reaction product was observed as discrete granules in the gastrodermis; activity was also observed in the testes and vitelline cells of males and females, respectively. No activity was noted in the foregut or esophageal glands of either worm. In light of previous biochemical studies on "hemoglobinase" activity in the schistosomes, it appears likely that a group of acid proteases may be involved in the ultimate digestion of hemoglobin. The absence of activity in the esophageal glands lends further support to the hypothesis that the gastrodermis is the site of the proteases responsible for hemoglobin digestion.

Animals↗
PubMed2006

A single-strand conformation polymorphism (SSCP) approach for investigating genetic interactions of Schistosoma haematobium and Schistosoma guineensis in Loum, Cameroon.

Single-strand conformation polymorphism (SSCP) analysis of the second internal transcribed spacer (ITS2) of nuclear ribosomal DNA provides a molecular tool for the identification of Schistosoma haematobium, Schistosoma guineensis and the hybrids of these two species. This molecular tool was utilized to provide a detailed analysis of the interactions between S. haematobium and S. guineensis in hybrid zones of Loum, Littoral Province, Cameroon. Individual hybrid schistosomes were identified within the natural populations collected from Loum in 1990, 1999 and 2000, which would have been misidentified as S. haematobium using solely morphological and sequence criteria. This study indicates the complexities of the hybridization between S. haematobium and S. guineensis and emphasizes the importance of assessing morphological, biological and molecular data to gain insights into the interaction of these two species over time.

Animals↗
PubMed1998

Relationship of impairment of schistosome 28-kilodalton glutathione S-transferase (GST) activity to expression of immunity to Schistosoma mattheei in calves vaccinated with recombinant Schistosoma bovis 28-kilodalton GST.

Sera from calves vaccinated with the recombinant Schistosoma bovis-derived 28-kDa glutathione S-transferase (28GST) and subsequently naturally or experimentally exposed to Schistosoma mattheei were studied for their content of specific immunoglobulin G (IgG) and IgA antibodies to recombinant S. bovis 28GST as well as for their capacity to inhibit the enzymatic activity of the antigen. The results were analyzed in regard to the presence (natural infection) or absence (experimental infection) of a protective effect(s) (reductions in worm burden, egg load, fecal egg counts, and excretion of viable eggs) toward S. mattheei challenge. Under such conditions, no differences in the IgG- and IgA-specific antibodies to recombinant S. bovis 28GST or in the ability to block the catalytic function of the antigen between the two groups were recorded. Nevertheless, correlation analysis between the specific antibody responses to recombinant S. bovis 28GST and the inhibition of GST activity suggested an association with IgG in experimentally infected vaccinated animals, while in naturally infected vaccinated calves, the inhibitory activity appeared to be linked to a greater degree with IgA. These results suggest that in contrast to schistosomiasis in humans, IgG antibodies in calves with schistosomiasis may exhibit inhibitory functions toward GST enzymatic activity or have a modulatory effect on IgA antibody properties. Furthermore, sera from animals immunized with recombinant S. bovis 28GST recognized the native S. mattheei 28GST and achieved comparable levels of inhibition of activity of recombinant S. bovis 28GST and S. matthei 28GST, indicating the presence of cross-reactive epitopes on these two molecules.

Animals↗
PubMed2002

Congenital infection with Schistosoma japonicum but not with Schistosoma bovis in sheep.

The present study investigated whether Schistosoma japonicum or Schistosoma bois could establish prenatally in lambs. Three ewes were exposed to S. japonicum by intramuscular injection of cercariae, and 3 ewes were exposed to S. bovis cercariae using the leg-emerging technique approximately 2 mo before delivery, and 1 age-matched pregnant ewe served as an uninfected control. The study lasted 18-20 wk after infection, which was 8-9 wk after delivery. All 6 exposed ewes became infected with either S. bovis or S. japonicum. Eight lambs were borne by the 7 ewes, of which 1 (S. bovis exposed) was dead and 1 (S. japonicum exposed) died at delivery. Of the 3 S. japonicum-exposed lambs, 2 were found infected. Four lambs born of S. bovis-exposed ewes were negative. Despite having no worms, these 4 S. bovis-exposed lambs as well as the 1 negative S. japonicum-exposed lamb had, in contrast to the nonexposed control lamb, few, but distinct, liver granulomas dominated by eosinophils and giant cells with large central necrotic areas but with no remnants of eggs or worms. Hence, congenital infection was demonstrated in S. japonicum-infected lambs, but not in S. bovis-infected ones.

Animals↗
PubMed1999

Oral immunization of mice against Schistosoma mansoni using drinking water from trays containing Biomphalaria alexandrina infected with Schistosoma mansoni.

Water collected from trays containing Biomphalaria alexandrina infected with Schistosoma mansoni at the time of cercariae shedding (SmISW) and trays containing clean, non-infected, B. alexandrina (NISW) and underground water (UW), were filtered used as a drinking water for 3 groups of albino mice males. After two months, blood samples were collected from the 3 groups and serum was tested for anti-cercarial IgG, then mice were infected with 150 S. mansoni cercariae. Eight weeks after infection, mice were perfused and adult S. mansoni worms were counted. Anti-cercarial IgG was positive in 23 (82.1%) out of the 28 samples collected from mice drinking SmISW and only in 2 (9.5%) out of the 21 samples collected from mice drinking NISW, while all samples collected from mice drinking UW were negative for anti-cercarial IgG (X2=45.897; P<0.001). Worm load was significantly lower in the group of mice drinking SmISW than mice drinking NISW (P=0.032) and mice drinking UW (P=0.02). In mice drinking SmISW, adult worm count showed significant negative correlation with anti-cercarial IgG concentration (Kendall's taub =-0.325 and P=0.018). The results indicate that antigens present in drinking water stimulate a level of immunity against schistosomiasis, (inhabitants of endemic areas) resulting in a lower intensity and severity of infection. Also, it may reduce the specificity of serological tests used for diagnosis of Schistosoma infection, based on antibody determination.

Administration, Oral↗
PubMed1988

Notes on the occurrence of tubercular spines in Schistosoma margrebowiei and Schistosoma mattheei.

Scanning electron microscopical (SEM) studies on the tegument of the bovid schistosomes, Schistosoma margrebowiei and Schistosoma mattheei have yielded conflicting results; certain authors observed the tubercles on the tegument of these species to be spined, while others reported that they are spineless. The present study indicates that the protrusion of tubercular spines is subject to phenotypic plasticity regulated by external factors such as the identity of the host species and whether or not the schistosome is paired.

Animals↗
PubMed1978

Schistosoma mekongi sp. n. from man and animals, compared with four geographic strains of Schistosoma japonicum.

Schistosoma mekongi sp. n. is described from man and animals in Cambodia. It is compared to 4 geographic strains of Schistosoma japonicum. It differs from S. japonicum in the size of embryonated eggs, in the length of the prepatent peroid in the mammalian host, and in its utilization of a different snail host. The relative usefulness of conventional morphologic criteria in the differentiation of Asian schistosomes is discussed.

Animals↗
PubMed1964

OBSERVATIONS ON THE TRANSMISSION OF SCHISTOSOMA HAEMATOBIUM AND SCHISTOSOMA BOVIS IN THE LAKE REGION OF TANGANYIKA.

Previous investigations have shown that in the Lake Region of Sukumaland, Tanganyika, where Schistosoma haematobium is highly endemic, Bulinus (Physopsis) nasutus is responsible for the transmission of that schistosome in small, temporary rain pools. This area is one of low rainfall, and large artificial reservoirs are the chief source of water in the dry season. The role of these reservoirs in S. haematobium transmission was studied over a period of about a year.Previous work in South Africa had indicated the potential danger of bovine schistosomes to man. S. bovis is a very common parasite in cattle in the Lake Region, and a search for its intermediate host or hosts, previously unidentified, was therefore also made.The results of this double investigation suggest that large bodies of water are relatively unimportant in the transmission of both S. haematobium and S. bovis. Bulinus (Physopsis) africanus is shown to be a second intermediate of S. haematobium and a vector of S. bovis as well. Transmission of these parasites by this snail takes place principally in streams.

Animals↗
PubMed1999

Increase of intestinal schistosomiasis after praziquantel treatment in a Schistosoma haematobium and Schistosoma mansoni mixed focus.

The recent emergence of a mixed focus of Schistosoma haematobium-Schistosoma mansoni, in the lower delta of the Senegal river, requires adapted control programmes. A mass treatment with praziquantel was organised in April 1994 by local authorities in three villages where populations had been examined. A total of 2042 subjects participated. In Savoigne S. haematobium prevailed (53% for prevalence), in Diagambaly S. haematobium (64%) and S. mansoni (76%) were both abundant, and in Boundoum S. mansoni prevailed (53%). Therapeutic coverage (80%) was assessed on a representative sample. A cohort of 968 treated subjects were followed-up 40, 100, 200 and 300 days after treatment. Six weeks after treatment, the average of egg excretion decreased by 95% for S. haematobium, ranging from 23 to one egg(s)/10 ml at Savoigne and from 14 to one egg(s)/10 ml at Diagambal. Conversely, egg excretion only decreased by 75% for S. mansoni, from 23 to six eggs/g at Boundoum and from 69 to 16 eggs/g at Diagambal, showing evidence of the low susceptibility of S. mansoni local strain to praziquantel. Ten months after treatment, reinfections with S. haematobium remained weak at Savoigne (two eggs/10 ml) while those with S. mansoni were so high at Boundoum (24 eggs/g) that they compensated the reduction of load induced by the treatment. At Diagambal, where the two parasites were present before treatment, the disappearance of the urinary schistosomiasis after treatment concurred with a dramatic increase of intestinal schistosomiasis. S. manoni egg excretion was seven times higher than before treatment (478 eggs/g). These different effects of treatment are discussed according to the ecology of transmission in the three villages.

Animals↗
PubMed2000

DNA copy number changes in Schistosoma-associated and non-Schistosoma-associated bladder cancer.

DNA copy number changes were investigated in 69 samples of schistosoma-associated (SA) and non-schistosoma-associated (NSA) squamous cell carcinoma (SCC) and transitional cell carcinoma (TCC) of the bladder by comparative genomic hybridization (CGH). DNA copy number changes were detected in 47 tumors. SA tumors had more changes than NSA tumors (mean, 7 vs. 4), whereas the number of changes in SCC and TCC tumors was similar. SA tumors displayed more gains than losses (1.7:1), whereas NSA tumors showed an equal number of gains and losses. Changes that were observed at similar frequencies in SCC and TCC, irrespective of the schistosomal status, included gains and high-level amplifications at 1q, 8q, and 20q and losses in 9p and 13q. These changes may be involved in a common pathway for bladder tumor development and progression independent of schistosomal status or histological subtype. Losses in 3p and gains at 5p were seen only in SCC (P < 0.01) and losses in 5q were more frequent in SA-SCC than in other tumors (P < 0.05). However, changes that were more frequent in TCC than those in SCC included gains at 17q (P < 0.01) and losses in 4q (P < 0.05) and 6q (P < 0.01). Gains and high-level amplifications at 5p were seen only in SA-SCC (P < 0. 01), whereas gains and high-level amplifications with minimal common overlapping regions at 11q13 were more frequently seen both in SA-SCC and SA-TCC tumors (P < 0.01). In addition to the above mentioned alterations, several other changes were also seen at lower frequencies. The variations in the DNA copy number changes observed in TCC, SCC, SA, and NSA bladder carcinomas suggest that these tumors have different genetic pathways.

Aged↗
PubMed1997

The influence of sex and age on antibody isotype responses to Schistosoma mansoni and Schistosoma japonicum in human populations in Kenya and the Philippines.

We have investigated the effects of host age and sex on human antibody isotype responses to Schistosoma mansoni and Schistosoma japonicum adult worm (AW) and soluble egg (SEA) antigens, using sera from subjects in Kenya and the Philippines. Similar trends with age were observed between the two populations despite host, parasite and environmental differences between the two geographical locations. IgE to AW increased with age, whereas most isotype responses to SEA decreased with age. IgG1, IgG3 and IgG4 subclass responses to adult worm, however, did not show a broadly rising or falling pattern with age. Males were found to have higher IgG1, IgG4 and IgE to AW in both populations. This sex difference remained significant in the Kenyan population even after controlling statistically for confounding factors such as age and differences in intensity of infection. Analysis of S. mansoni and S. japonicum adult worm antigens reactive with IgE revealed a predominant 22 kDa band in both parasites. Only those individuals with relatively high IgE titres specifically reactive with S. mansoni or S. japonicum AW had detectable IgE against Sj22 or Sm22.

Adolescent↗