A model of T-cell unresponsiveness using the male-specific antigen, H-Y

Granuloma formation in schistosomiasis japonica differs in several respects from those observed in Schistosoma mansoni infections. We have utilized the lung granuloma model in mice sensitized with subcutaneous injection of Schistosoma japonicum eggs to study the kinetics and mechanisms of this response. Animals injected subcutaneously with a range of 50–50,000 S. japonicum eggs elicited a significant pulmonary granulomatous response around ova subsequently injected intravenously. The pulmonary granulomas were formed of macrophages, lymphocytes, and eosinophils. Both antithymocyte globulin and antieosinophil sera reduced significantly the size of the granulomas and depleted the corresponding cell. Nude athymic mice developed markedly reduced pulmonary granulomas as did mice treated with niridazole or hydrocortisone. Sensitization to the egg antigens was demonstrable as both immediate and arthus-type footpad responses. Our data show that cell-mediated pulmonary granulomas can form around S. japonicum eggs in animals previously sensitized by the subcutaneous route. This model may provide further insights into the pathogenesis of S. japonicum granuloma.     

Eosinophi-mediated destruction of Schistosoma mansoni eggs in vitro. II. The role of cytophilic antibody

Peritoneal exudative eosinophils obtained from Schistosoma mansoni-infected CBA/J mice cause morphological damage to isolated S. mansoni eggs in a 24 hr co-cultivation system in vitro. This egg-destructive activity was complement-independent and was abolished by trypsinization of the cells prior to co-cultivation. Trypsinized cells could be passively sensitized to renewed egg-destructive capacity by preincubation or co-gcultivation with immune sera, containing antibodies against a soluble egg antigenic preparation (SEA). Solid phase absorption of immune sera with SEA coupled to Sepharose 4B lowered the anti-egg antibody titers of these sera and eliminated their ability to sensitize trypsinized eosinophils. Sera from uninfected mice or from mice infected with Trichinella spiralis did not sensitize trypsinized cells. Addition of immune sera to eosinophil-rich cell populations obtained from uninfected mice also enhanced the egg-destructive capacity of these otherwise non-reactive cells. Therefore, eosinophil-mediated destruction of S. mansoni eggs may be directed by cytophilic antigen-specific factors in sera from S. mansoni infected hosts.     

Schistosomiasis mansoni, haematobia, and japonica in hamsters: liver granuloma measurements

Differences in the granulomatous response of hamsters infected with Schistosoma mansoni, Schistosoma haematobium, or Schistosoma japonicum were studied by measuring granulomas formed around eggs in the livers at 1, 3, 5, 11, and 19 week intervals after patency of the infections. For each species, the mean diameters of both granulomas containing only 1 egg and granulomas selected at random were determined. The mean volume of single egg granulomas in S. mansoni-infected hamsters was greater than in those with other species at all time intervals studied. The decrease in single egg granuloma size with time occurred more gradually in S. mansoni infections. The mean volume of granulomas measured at random was greatest in S. japoracum-infected animals at 1, 3, and 11 weeks after patency; was greatest in S. haematobium-iufected. hamsters at 5 and 19 weeks; and was least in S. mansoni-infected hamsters at all time periods. During the 19 week period following patency, the mean volume of randomly measured granulomas increased with time in S. haematobium infections, decreased gradually in S. mansoni infections, and decreased markedly in S. japonicum infections. Multi-egg granulomas represented 2–6% of all granulomas measured in S. mansoni infections, 38–68% in S. haematobium infections, and 20–53% in S. japonicum infections. An estimated proportion of the liver occupied by granulomas, i.e., a lesion-to-tissue ratio, was computed. There was no consistent difference in this ratio among the 3 species when the data were grouped in comparable intervals of mean number of eggs per g of liver. The lesion-to-tissue ratio increased with increasing numbers of eggs per g of liver. The host response of hamsters to these 3 species of schistosomes differed markedly even at comparable levels of eggs per g of liver. This study provides further evidence of an intrinsic qualitative difference in the eggs of the 3 species. The species of eggs present in tissues apparently has greater influence on the host response than does the quantity of eggs present.     

A New Mouse Model for Female Genital Schistosomiasis

Background

Over 112 million people worldwide are infected with Schistosoma haematobium, one of the most prevalent schistosome species affecting humans. Female genital schistosomiasis (FGS) occurs when S. haematobium eggs are deposited into the female reproductive tract by adult worms, which can lead to pelvic pain, vaginal bleeding, genital disfigurement and infertility. Recent evidence suggests co-infection with S. haematobium increases the risks of contracting sexually transmitted diseases such as HIV. The associated mechanisms remain unclear due to the lack of a tractable animal model. We sought to create a mouse model conducive to the study of immune modulation and genitourinary changes that occur with FGS.

Methods

To model FGS in mice, we injected S. haematobium eggs into the posterior vaginal walls of 30 female BALB/c mice. A control group of 20 female BALB/c mice were injected with uninfected LVG hamster tissue extract. Histology, flow cytometry and serum cytokine levels were assessed at 2, 4, 6, and 8 weeks post egg injection. Voiding studies were performed at 1 week post egg injection.

Results

Vaginal wall injection with S. haematobium eggs resulted in synchronous vaginal granuloma development within 2 weeks post-egg injection that persisted for at least 6 additional weeks. Flow cytometric analysis of vaginal granulomata revealed infiltration by CD4⁺ T cells with variable expression of the HIV co-receptors CXCR4 and CCR5. Granulomata also contained CD11b⁺F4/80⁺ cells (macrophages and eosinophils) as well as CXCR4⁺MerTK⁺ macrophages. Strikingly, vaginal wall-injected mice featured significant urinary frequency despite the posterior vagina being anatomically distant from the bladder. This may represent a previously unrecognized overactive bladder response to deposition of schistosome eggs in the vagina.

Conclusion

We have established a new mouse model that could potentially enable novel studies of genital schistosomiasis in females. Ongoing studies will further explore the mechanisms by which HIV target cells may be drawn into FGS-associated vaginal granulomata.     

A Novel Mouse Model of Schistosoma haematobium Egg-Induced Immunopathology

Schistosoma haematobium is the etiologic agent for urogenital schistosomiasis, a major source of morbidity and mortality for more than 112 million people worldwide. Infection with S. haematobium results in a variety of immunopathologic sequelae caused by parasite oviposition within the urinary tract, which drives inflammation, hematuria, fibrosis, bladder dysfunction, and increased susceptibility to urothelial carcinoma. While humans readily develop urogenital schistosomiasis, the lack of an experimentally-tractable model has greatly impaired our understanding of the mechanisms that underlie this important disease. We have developed an improved mouse model of S. haematobium urinary tract infection that recapitulates several aspects of human urogenital schistosomiasis. Following microinjection of purified S. haematobium eggs into the bladder wall, mice consistently develop macrophage-rich granulomata that persist for at least 3 months and pass eggs in their urine. Importantly, egg-injected mice also develop urinary tract fibrosis, bladder dysfunction, and various urothelial changes morphologically reminiscent of human urogenital schistosomiasis. As expected, S. haematobium egg-induced immune responses in the immediate microenvironment, draining lymph nodes, and systemic circulation are associated with a Type 2-dominant inflammatory response, characterized by high levels of interleukin-4, eosinophils, and IgE. Taken together, our novel mouse model may help facilitate a better understanding of the unique pathophysiological mechanisms of epithelial dysfunction, tissue fibrosis, and oncogenesis associated with urogenital schistosomiasis.     

Genetic Diversity of Schistosoma haematobium Eggs Isolated from Human Urine in Sudan

The genetic diversity of Schistosoma haematobium remains largely unstudied in comparison to that of Schistosoma mansoni. To characterize the extent of genetic diversity in S. haematobium among its definitive host (humans), we collected S. haematobium eggs from the urine of 73 infected schoolchildren at 5 primary schools in White Nile State, Sudan, and then performed a randomly amplified polymorphic DNA marker ITS2 by PCR-RFLP analysis. Among 73 S. haematobium egg-positive cases, 13 were selected based on the presence of the S. haematobium satellite markers A4 and B2 in their genomic DNA, and used for RFLP analysis. The 13 samples were subjected to an RFLP analysis of the S. haematobium ITS2 region; however, there was no variation in size among the fragments. Compared to the ITS2 sequences obtained for S. haematobium from Kenya, the nucleotide sequences of the ITS2 regions of S. haematobium from 4 areas in Sudan were consistent with those from Kenya (> 99%). In this study, we demonstrate for the first time that most of the S. haematobium population in Sudan consists of a pan-African S. haematobium genotype; however, we also report the discovery of Kenyan strain inflow into White Nile, Sudan.     

Eosinophils and immune mechanisms. IV. Culture conditions, antigen requirements, production kinetics and immunologic specificity of the lymphokine eosinophil stimulation promoter.

The culture conditions which contribute to the production of the lymphokine, eosinophil stimulation promoter (ESP), have been investigated. Spleen or lymph node cells from mice infected for 8–10 weeks with the helminth Schistosoma mansoni respond to challenge with a soluble egg antigenic preparation (SEA) from S. mansoni eggs by the elaboration of ESP into the culture medium. Exposure to as little as 0.1 μg of SEA elicits this response. Furthermore, 30 min of exposure to antigen is sufficient to stimulate subsequent ESP production. Production begins within 4 hr, is rapid for 12 hr, and continues for at least another 8 hr. The use of this information allows the standardization of ESP production to be such that the concentration of SEA is insufficient to interfere with the indirect assay of ESP upon eosinophil-rich peritoneal exudates from S. mansoni-infected mice. The specificity of the direct assay elicited by SEA was confirmed, and the ability of the lymphokine to stimulate eosinophil migration from eosinophil-rich peritoneal exudates from either S. mansoni-or Trichinella spiralis-infected mice was demonstrated.     

Granuloma formation to Capillaria hepatica eggs. I. Descriptive definition

The course of the cellular response in the liver to nonembryonated Capillaria hepatica (Bancroft, 1893) eggs given by intravenous injection into the portal circulation of unsensitized and sensitized mice was studied qualitatively and quantitatively. A gradual infiltration of predominantly mononuclear cells occurred around the eggs in the liver, leading to the formation of distinct granulomatous lesions characterized by macrophages and lymphocytes. This was followed by an infiltration of eosinophils. Previous intraperitoneal sensitization led to an earlier and an enhanced reaction to an intravenous challenge with eggs. Specificity of the cellular response was suggested by the lack of an enhanced reaction to presensitization with eggs of a closely related species, Trichuris muris. These studies indicate that granuloma formation to C. hepatica eggs has an immunological basis and furthermore the cell composition of the granuloma would suggest that a cell-mediated component may be involved as part of the specific response.     

Proteomic identification of IPSE/alpha-1 as a major hepatotoxin secreted by Schistosoma mansoni eggs

Background

Eggs deposited in the liver of the mammalian host by the blood fluke parasite, Schistosoma mansoni, normally drive a T-helper-2 (Th2)-mediated granulomatous response in immune-competent mice. By contrast, in mice deprived of T-cells and incapable of producing granulomata, egg-secreted proteins (ESP) induce acute hepatic injury and death. Previous work has shown that one such ESP, the T2 ribonuclease known as omega-1, is hepatotoxic in vivo in that specific antisera to omega-1 prevent hepatocyte damage.

Methodology/Principal Findings

Using an in vitro culture system employing mouse primary hepatocytes and alanine transaminase (ALT) activity as a marker of heptocyte injury, we demonstrated that S. mansoni eggs, egg-secreted proteins (ESP), soluble-egg antigen (SEA), and omega-1 are directly hepatotoxic and in a dose-dependent manner. Depletion of omega-1 using a monoclonal antibody abolished the toxicity of pure omega-1 and diminished the toxicity in ESP and SEA by 47 and 33%, respectively. Anion exchange chromatography of ESP yielded one predominant hepatotoxic fraction. Proteomics of that fraction identified the presence of IPSE/alpha-1 (IL-4 inducing principle from S. mansoni eggs), a known activator of basophils and inducer of Th2-type responses. Pure recombinant IPSE/alpha-1 also displayed a dose-dependent hepatotoxicity in vitro. Monoclonal antibody depletion of IPSE/alpha-1 abolished the latter''s toxicity and diminished the total toxicity of ESP and SEA by 32 and 35%, respectively. Combined depletion of omega-1 and IPSE/alpha-1 diminished hepatotoxicity of ESP and SEA by 60 and 58% respectively.

Conclusions

We identified IPSE/alpha-1 as a novel hepatotoxin and conclude that both IPSE/alpha-1 and omega-1 account for the majority of the hepatotoxicity secreted by S. mansoni eggs.     

Significantly reduced intensity of infection but persistent prevalence of schistosomiasis in a highly endemic region in mali after repeated treatment

Background

Preventive chemotherapy against schistosomiasis has been implemented since 2005 in Mali, targeting school-age children and adults at high risk. A cross-sectional survey was conducted in 2010 to evaluate the impact of repeated treatment among school-age children in the highly-endemic region of Segou.

Methodology/Principal Findings

The survey was conducted in six sentinel schools in three highly-endemic districts, and 640 school children aged 7–14 years were examined. Infections with Schistosoma haematobium and S. mansoni were diagnosed with the urine filtration and the Kato-Katz method respectively. Overall prevalence of S. haematobium infection was 61.7%, a significant reduction of 30% from the baseline in 2004 (p<0.01), while overall prevalence of S. mansoni infection was 12.7% which was not significantly different from the baseline. Overall mean intensity of S. haematobium and S. mansoni infection was 180.4 eggs/10 ml of urine and 88.2 epg in 2004 respectively. These were reduced to 33.2 eggs/10 ml of urine and 43.2 epg in 2010 respectively, a significant reduction of 81.6% and 51% (p<0.001). The proportion of heavy S. haematobium infections was reduced from 48.8% in 2004 to 13.8% in 2010, and the proportion of moderate and heavy S. mansoni infection was reduced from 15.6% in 2004 to 9.4% in 2010, both significantly (p<0.01). Mathematical modelling suggests that the observed results were in line with the expected changes.

Conclusions/Significance

Significant reduction in intensity of infection on both infections and modest but significant reduction in S. haematobium prevalence were achieved in highly-endemic Segou region after repeated chemotherapy. However, persistent prevalence of both infections and relatively high level of intensity of S. mansoni infection suggest that more intensified control measures be implemented in order to achieve the goal of schistosomiasis elimination. In addition, closer monitoring and evaluation activities are needed in the programme to monitor the drug tolerance and to adjust treatment focus.     

Schistosome eggs stimulate reactive oxygen species production to enhance M2 macrophage differentiation and promote hepatic pathology in schistosomiasis

Schistosomiasis is a neglected tropical disease of public health concern. The most devastating pathology in schistosomiasis japonica and mansoni is mainly attributed to the egg-induced granulomatous response and secondary fibrosis in host liver, which may lead to portal hypertension or even death of the host. Schistosome eggs induce M2 macrophages-rich granulomas and these M2 macrophages play critical roles in the maintenance of granuloma and subsequent fibrosis. Reactive oxygen species (ROS), which are highly produced by stimulated macrophages during infection and necessary for the differentiation of M2 macrophages, are massively distributed around deposited eggs in the liver. However, whether ROS are induced by schistosome eggs to subsequently promote M2 macrophage differentiation, and the possible underlying mechanisms as well, remain to be clarified during S. japonicum infection. Herein, we observed that extensive expression of ROS in the liver of S. japonicum-infected mice. Injection of ROS inhibitor in infected mice resulted in reduced hepatic granulomatous responses and fibrosis. Further investigations revealed that inhibition of ROS production in S. japonicum-infected mice reduces the differentiation of M2, accompanied by increased M1 macrophage differentiation. Finally, we proved that S. japonicum egg antigens (SEA) induce a high level of ROS production via both nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and mitochondria in macrophages. Our study may help to better understand the mechanism of schistosomiasis japonica-induced hepatic pathology and contribute to the development of potential therapeutic strategies by interfering with ROS production.     

High Genetic Variability of Schistosoma haematobium in Mali and Nigeria

Schistosoma haematobium is one of the most prevalent parasitic flatworms, infecting over 112 million people in Africa. However, little is known about the genetic diversity of natural S. haematobium populations from the human host because of the inaccessible location of adult worms in the host. We used 4 microsatellite loci to genotype individually pooled S. haematobium eggs directly from each patient sampled at 4 endemic locations in Africa. We found that the average allele number of individuals from Mali was significantly higher than that from Nigeria. In addition, no significant difference in allelic composition was detected among the populations within Nigeria; however, the allelic composition was significantly different between Mali and Nigeria populations. This study demonstrated a high level of genetic variability of S. haematobium in the populations from Mali and Nigeria, the 2 major African endemic countries, suggesting that geographical population differentiation may occur in the regions.     

Prevalence of urogenital and intestinal schistosomiasis among school children in South-west Nigeria

BackgroundThe risk of co-infection with Schistosoma haematobium and S. mansoni and the potential harmful effect on morbidity and control is enhanced by the overlapping distribution of both species in sub-Saharan Africa. Despite the reported high endemicity of both species in Nigeria, studies on the spread and effect of their mixed infection are limited. Therefore, a cross-sectional survey was conducted among school children in two communities in South-west Nigeria to investigate the prevalence of mixed human schistosome infection, intensity, and possible ectopic egg elimination.MethodsUrine and stool samples were collected from consenting school children in Ilie and Ore communities of Osun State, Nigeria. Schistosoma haematobium eggs were detected in urine using the urine filtration technique, while S. mansoni eggs were detected in stool using the Kato–Katz thick smear technique.ResultsThe study enrolled 466 primary and secondary school children (211; 45.3% males vs. 255; 54.7% females; mean age 11.6 ± 3.16 years). The overall prevalence of schistosomiasis was 40% (185/466), with 19% (89/466) recording single S. haematobium infection while 9% (41/465) had a single S. mansoni infection. The geometric mean egg count for S. haematobium was 189.4 egg/10ml urine; 95% CI: range 115.9–262.9, while for S. mansoni, it was 115.7 epg; 95% CI: range 78.4–152.9. The prevalence of ectopic S mansoni (S. mansoni eggs in urine) was 4.7%, while no ectopic S. haematobium (S. haematobium eggs in stool) was recorded. Mixed infection of S. haematobium/S. mansoni had a prevalence of 9.5% (44/466). More females (54.5%) presented with S. haematobium/S. mansoni co-infection. For both parasites, males had higher infection intensity, with a significant difference observed with S. haematobium (p = 0.0004). Hematuria was significant in individuals with single S. haematobium infection (p = 0.002), mixed ectopic S. haematobium/S. mansoni (p = 0.009) and mixed S. haematobium/S. mansoni/ectopic S. mansoni (p = 0.0003).ConclusionsThese findings suggest the probability of interspecific interactions between S. haematobium and S. mansoni. Scaling up of mass administration of praziquantel and control measures in the study areas is highly desirable.     

Host tissue proteomics reveal insights into the molecular basis of Schistosoma haematobium-induced bladder pathology

Urogenital schistosomiasis remains a major public health concern worldwide. In response to egg deposition, the host bladder undergoes gross and molecular morphological changes relevant for disease manifestation. However, limited mechanistic studies to date imply that the molecular mechanisms underlying pathology are not well-defined. We leveraged a mouse model of urogenital schistosomiasis to perform for the first time, proteome profiling of the early molecular events that occur in the bladder after exposure to S. haematobium eggs, and to elucidate the protein pathways involved in urogenital schistosomiasis-induced pathology. Purified S. haematobium eggs or control vehicle were microinjected into the bladder walls of mice. Mice were sacrificed seven days post-injection and bladder proteins isolated and processed for proteome profiling using mass spectrometry. We demonstrate that biological processes including carcinogenesis, immune and inflammatory responses, increased protein translation or turnover, oxidative stress responses, reduced cell adhesion and epithelial barrier integrity, and increased glucose metabolism were significantly enriched in S. haematobium infection. S. haematobium egg deposition in the bladder results in significant changes in proteins and pathways that play a role in pathology. Our findings highlight the potential bladder protein indicators for host-parasite interplay and provide new insights into the complex dynamics of pathology and characteristic bladder tissue changes in urogenital schistosomiasis. The findings will be relevant for development of improved interventions for disease control.     

Urinary Estrogen Metabolites and Self-Reported Infertility in Women Infected with Schistosoma haematobium

Background

Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsive cells. In addition, schistosome derived catechol-estrogens induce genotoxicity that result in estrogen-DNA adducts. These catechol estrogens and the catechol-estrogen-DNA adducts can be isolated from sera of people infected with S. haematobium. The aim of this study was to study infertility in females infected with S. haematobium and its association with the presence of schistosome-derived catechol-estrogens.

Methodology/Principal Findings

A cross-sectional study was undertaken of female residents of a region in Bengo province, Angola, endemic for schistosomiasis haematobia. Ninety-three women and girls, aged from two (parents interviewed) to 94 years were interviewed on present and previous urinary, urogenital and gynecological symptoms and complaints. Urine was collected from the participants for egg-based parasitological assessment of schistosome infection, and for liquid chromatography diode array detection electron spray ionization mass spectrometry (LC/UV-DAD/ESI-MSn) to investigate estrogen metabolites in the urine. Novel estrogen-like metabolites, potentially of schistosome origin, were detected in the urine of participants who were positive for eggs of S. haematobium, but not detected in urines negative for S. haematobium eggs. The catechol-estrogens/ DNA adducts were significantly associated with schistosomiasis (OR 3.35; 95% CI 2.32–4.84; P≤0.001). In addition, presence of these metabolites was positively associated with infertility (OR 4.33; 95% CI 1.13–16.70; P≤0.05).

Conclusions/Significance

Estrogen metabolites occur widely in diverse metabolic pathways. In view of the statistically significant association between catechol-estrogens/ DNA adducts and self-reported infertility, we propose that an estrogen-DNA adduct mediated pathway in S. haematobium-induced ovarian hormonal deregulation could be involved. In addition, the catechol-estrogens/ DNA adducts described here represent potential biomarkers for schistosomiasis haematobia.     

Ascaris suum: Immunosuppression in mice during acute infection

Mice inoculated by stomach intubation with 10,000 embryonated Ascaris suum eggs, 4, 11, or 21 days before an intraperitoneal (ip) immunization with 2 × 10⁸ sheep erythrocytes (SRBC) had reduced numbers of direct (IgM) splenic hemolytic plaques measured at 4 days after immunization and only a marginal reduction in indirect plaques (IgG) measured at 9 days after immunization. Lower dosages of Ascaris eggs or simultaneous inoculation of Ascaris eggs and SRBC did not suppress antibody responses to SRBC. No reduction in a secondary antibody response to SRBC injected 4 days after Ascaris inoculation was observed. IgM and IgG hemagglutinin titers, as distinguished by 2-mercaptoethanol sensitivity, were suppressed in mice injected ip with 10⁸ SRBC 10 days following inoculation of 10,000 Ascaris eggs, but titers in both Ig classes were similar in infected and control mice injected with 2 × 10⁹ SRBC. At Day 20, antibody titers following ip injection of 1.0 or 100 μg of ovalbumin in alum were reduced in mice infected with 10,000 Ascaris eggs 4 days before antigen injection.Contact hypersensitivity to oxazalone was not altered in mice sensitized at 5 or 14 days after inoculation of 10,000 Ascaris eggs. The delayed hypersensitivity response, measured by footpad swelling, to an optimum intravenous sensitizing dosage of SRBC was inhibited in mice sensitized 10 days after Ascaris infection, but not inhibited in mice sensitized at 21 or 32 days after infection. In contrast, the delayed hypersensitivity response to subcutaneous sensitization with SRBC 10 days after Ascaris infection was not altered.     

Schistosoma haematobium total antigen induces increased proliferation, migration and invasion, and decreases apoptosis of normal epithelial cells

Schistosome worms are blood-dwelling flukes that cause chronic infection in more than 200 million people and are thought to be responsible for 500,000 deaths annually. During infection with Schistosoma haematobium, eggs are deposited in the mucosa and submucosa of the bladder and lower ureters. Squamous cell carcinoma (SCC) of the bladder is a long-term sequela of chronic infection. The mechanisms underlying the association between S. haematobium and SCC of the bladder are largely unknown, with all reports to date exclusively demonstrating epidemiological evidence linking S. haematobium infection with SCC of the bladder. We hypothesised that the parasite antigens might induce alterations in epithelial cells towards cancer. For this we used Chinese Hamster Ovary (CHO) cells and treated the cells in culture with S. haematobium total antigen (Sh). Our results showed increased proliferation, increased S-phase and decreased apoptosis, as well as down-regulation of tumour suppressor p27 and up-regulation of anti-apoptotic molecule Bcl-2 in Sh-treated cells compared with controls. We also found increased migration and invasion. To our knowledge, this is the first report demonstrating alterations of normal epithelial cells as a direct effect of S. haematobium antigens.     

A Schistosoma haematobium-Specific Real-Time PCR for Diagnosis of Urogenital Schistosomiasis in Serum Samples of International Travelers and Migrants

Background

Diagnosis of urogenital schistosomiasis by microscopy and serological tests may be elusive in travelers due to low egg load and the absence of seroconversion upon arrival. There is need for a more sensitive diagnostic test. Therefore, we developed a real-time PCR targeting the Schistosoma haematobium-specific Dra1 sequence.

Methodology/Principal Findings

The PCR was evaluated on urine (n = 111), stool (n = 84) and serum samples (n = 135), and one biopsy from travelers and migrants with confirmed or suspected schistosomiasis. PCR revealed a positive result in 7/7 urine samples, 11/11 stool samples and 1/1 biopsy containing S. haematobium eggs as demonstrated by microscopy and in 22/23 serum samples from patients with a parasitological confirmed S. haematobium infection. S. haematobium DNA was additionally detected by PCR in 7 urine, 3 stool and 5 serum samples of patients suspected of having schistosomiasis without egg excretion in urine and feces. None of these suspected patients demonstrated other parasitic infections except one with Blastocystis hominis and Entamoeba cyst in a fecal sample. The PCR was negative in all stool samples containing S. mansoni eggs (n = 21) and in all serum samples of patients with a microscopically confirmed S. mansoni (n = 22), Ascaris lumbricoides (n = 1), Ancylostomidae (n = 1), Strongyloides stercoralis (n = 1) or Trichuris trichuria infection (n = 1). The PCR demonstrated a high specificity, reproducibility and analytical sensitivity (0.5 eggs per gram of feces).

Conclusion/Significance

The real-time PCR targeting the Dra1 sequence for S. haematobium-specific detection in urine, feces, and particularly serum, is a promising tool to confirm the diagnosis, also during the acute phase of urogenital schistosomiasis.