Morbidity in schistosomiasis: an update

Anti-fibrotic Effect of Oral Versus Intraperitoneal Administration of Gold Nanoparticles in Hepatic Schistosoma mansoni-Infected Mice

BACKGROUND

Schistosomiasis significantly impacts public health, as it causes severe morbidity. Infections caused by Schistosoma mansoni (S. mansoni) can be treated with gold nanoparticles (AuNPs). This study aims to determine the most effective route of AuNPs administration and the magnitude of its anti-fibrotic effect.

METHODS

In the five groups' in vivo assay design, AuNPs were administered intraperitoneally (1 mg/kg) and orally (1 mg/100 g) to S. mansoni-infected mice. Biochemical parameters (serum levels of albumin and liver enzymes alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured. The histological changes of the liver in distinct groups were evaluated using Hematoxylin and Eosin, Masson's trichrome, and immunohistochemical stains.

RESULTS

Infection with S. mansoni was associated with substantial changes in the histological architecture of liver tissue and abnormal levels of hepatic function tests (albumin, AST, and ALT). Schistosoma infected hepatocytes exhibited an abnormal microscopic morphology, granuloma formation and aggressive fibrosis. AuNPs restored the liver histological architecture with a highly significant anti-fibrotic effect and significantly corrected hepatic function test levels. Intraperitoneal administration of AuNPs resulted in the most significant anti-fibrotic effect against hepatic S. mansoni infection as observed in all histological sections with Masson's trichrome being the best stain to represent this fact.

CONCLUSION

For treating S. mansoni-induced chronic liver fibrosis, intraperitoneal administration of AuNPs is a successful and effective route of administration that can be recommended.

Urinary interleukins (IL)-6 and IL-10 in schoolchildren from an area with low prevalence of Schistosoma haematobium infections in coastal Kenya

Urinary cytokines are gaining traction as tools for assessing morbidity in infectious and non-infectious inflammatory diseases of the urogenital tract. However, little is known about the potential of these cytokines in assessing morbidity due to S. haematobium infections. Factors that may influence the urinary cytokine levels as morbidity markers also remain unknown. Therefore the objective of the present study was to assess how urinary interleukins (IL-) 6 and 10 are associated with gender, age, S. haematobium infections, haematuria and urinary tract pathology and; 2) to assess the effects of urine storage temperatures on the cytokines. This was a cross-sectional study in 2018 involving 245 children aged 5-12 years from a S. haematobium endemic area of coastal Kenya. The children were examined for S. haematobium infections, urinary tract morbidity, haematuria and urinary cytokines (IL-6 and IL-10). Urine specimens were also stored at -20°C, 4°C or 25°C for 14 days before being assayed for IL6 and IL-10 using ELISA. The overall prevalence of S. haematobium infections, urinary tract pathology, haematuria, urinary IL-6 and urinary IL-10 were 36.3%, 35.8%, 14.8%, 59.4% and 80.5%, respectively. There were significant associations between prevalence of urinary IL-6, but not IL-10, and age, S. haematobium infection and haematuria (p = 0.045, 0.011 and 0.005, respectively) but not sex or ultrasound-detectable pathology. There were significant differences in IL-6 and IL-10 levels between urine specimens stored at -20°C and those stored at 4°C (p<0.001) and, between those stored at 4°C and those stored at 25°C (p<0.001). Urinary IL-6, but not IL-10, was associated with children's age, S. haematobium infections and haematuria. However, both urinary IL-6 and IL-10 were not associated with urinary tract morbidity. Both IL-6 and IL-10 were sensitive to urine storage temperatures.

CRISPR/Cas9-mediated gene knockout of Sj16 in Schistosoma japonicum eggs upregulates the host-to-egg immune response

Schistosomiasis is an important, neglected tropical disease. Schistosoma japonicum can evade host attacks by regulating the host's immunity, causing continuous infection. However, interactions between the host's immune system and S. japonicum are unclear. Our previous research found that the Sj16 protein isolated from S. japonicum has an anti-inflammatory effect in the host. However, the role of Sj16 in the regulation of host immunity in S. japonicum infection is not clear. Here, we applied the CRISPR/Cas9 technique to knockout Sj16 in S. japonicum eggs and investigated the effect of Sj16 in regulating host immunity. We found egg viability decreased after Sj16 knockout. In addition, we found granulomatous inflammation increased, the T-cell immune response enhanced and the immune microenvironment changed in mice model injected with Sj16-knockout eggs by tail vein. These findings suggested that S. japonicum could regulate host immunity through Sj16 to evade the host immune attack and cause continuous infection. In addition, we confirmed the application of CRISPR/Cas9-mediated gene reprogramming for functional genomics in S. japonicum.

Algorithm for diagnosis of early Schistosoma haematobium using prodromal signs and symptoms in pre-school age children in an endemic district in Zimbabwe

Introduction

Prompt diagnosis of acute schistosomiasis benefits the individual and provides opportunities for early public health intervention. In endemic areas schistosomiasis is usually contracted during the first 5 years of life, thus it is critical to look at how the infection manifests in this age group. The aim of this study was to describe the prodromal signs and symptoms of early schistosomiasis infection, correlate these with early disease progression and risk score to develop an easy to use clinical algorithm to identify early Schistosoma haematobium infection cases in resource limited settings.

Methodology

Two hundred and four, preschool age children who were lifelong residence of a schistosomiasis endemic district and at high risk of acquiring schistosomiasis were followed up from July 2019 to December 2019, during high transmission season. The children received interval and standard full clinical evaluations and laboratory investigations for schistosomiasis by clinicians blinded from their schistosomiasis infection status. Diagnosis of S. haematobium was by urine filtration collected over three consecutive days. Signs and symptoms of schistosomiasis at first examination visit were compared to follow-up visits. Signs and symptoms common on the last schistosomiasis negative visit (before a subsequent positive) were assigned as early schistosomiasis infection (ESI), after possible alternative causes were ruled out. Logistic regression identified clinical predictors. A model based score was assigned to each predictor to create a risk for every child. An algorithm was created based on the predictor risk scores and validated on a separate cohort of 537 preschool age children.

Results

Twenty-one percent (42) of the participants were negative for S. haematobium infection at baseline but turned positive at follow-up. The ESI participants at the preceding S. haematobium negative visit had the following prodromal signs and symptoms in comparison to non-ESI participants; pruritic rash adjusted odds ratio (AOR) = 21.52 (95% CI 6.38–72.66), fever AOR = 82 (95% CI 10.98–612), abdominal pain AOR = 2.6 (95% CI 1.25–5.43), pallor AOR = 4 (95% CI 1.44–11.12) and a history of facial/body swelling within the previous month AOR = 7.31 (95% CI 3.49–15.33). Furthermore 16% of the ESI group had mild normocytic anaemia, whilst 2% had moderate normocytic anaemia. A risk score model was created using a rounded integer from the relative risks ratios. The diagnostic algorithm created had a sensitivity of 81% and a specificity of 96.9%, Positive predictive value = 87.2% and NPV was 95.2%. The area under the curve for the algorithm was 0.93 (0.90–0.97) in comparison with the urine dipstick AUC = 0.58 (0.48–0.69). There was a similar appearance in the validation cohort as in the derivative cohort.

Conclusion

This study demonstrates for the first time prodromal signs and symptoms associated with early S. haematobium infection in pre-school age children. These prodromal signs and symptoms pave way for early intervention and management, thus decreasing the harm of late diagnosis. Our algorithm has the potential to assist in risk-stratifying pre-school age children for early S. haematobium infection. Independent validation of the algorithm on another cohort is needed to assess the utility further.

Schistosoma haematobium causes urogenital infection and in endemic areas schistosomiasis is usually contracted during the first 5 years of life, thus it is critical to look at how the infection manifests in this age group. Prompt diagnosis of acute schistosomiasis is required to benefit the individuals and provide opportunities for early treatment and public health intervention. The study examined symptoms that correlated with early disease progression and risk scored to develop an easy to use clinical algorithm to identify early S. haematobium infection cases. The children received standard full clinical evaluations by clinicians who were blinded from schistosomiasis diagnosis by parasitological examination. An algorithm was created based on the predictor risk scores and participants had the following prodromal signs and symptoms; pruritic rash, abdominal pain, pallor, abdominal pain, inguinal lymphadenopathy and a history of facial/body swelling within the previous month. A risk score model, diagnostic algorithm, was created that compared to urine dipstick and parasitology. This study demonstrates the clinical signs and symptoms associated with early S. haematobium infection in pre-school age children. These prodromal signs and symptoms pave way for early intervention and management, thus decreasing the harm of late diagnosis common in populations from endemic areas.

Atypical Presentation of Acute Appendicitis with Schistosomiasis

Schistosomiasis is a parasitic infection that is induced by different species of Schistosoma. The infection can manifest with a variety of different pathologies depending on the involved system and causative species. Schistosoma-induced appendicitis is rare in developed countries. We discuss a case of a middle-aged female who was diagnosed with acute appendicitis and underwent appendectomy. Upon histopathological examination of the resected appendix, Schistosoma infestation was identified as the underlying cause.

Integrative genomic expression analysis reveals stable differences between lung cancer and systemic sclerosis

BACKGROUND

The incidence and mortality of lung cancer are the highest among all cancers. Patients with systemic sclerosis show a four-fold greater risk of lung cancer than the general population. However, the underlying mechanism remains poorly understood.

METHODS

The expression profiles of 355 peripheral blood samples were integratedly analyzed, including 70 cases of lung cancer, 61 cases of systemic sclerosis, and 224 healthy controls. After data normalization and cleaning, differentially expressed genes (DEGs) between disease and control were obtained and deeply analyzed by bioinformatics methods. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed online by DAVID and KOBAS. The protein-protein interaction (PPI) networks were constructed from the STRING database.

RESULTS

From a total of 14,191 human genes, 299 and 1644 genes were identified as DEGs in systemic sclerosis and lung cancer, respectively. Among them, 64 DEGs were overlapping, including 36 co-upregulated, 10 co-downregulated, and 18 counter-regulated DEGs. Functional and enrichment analysis showed that the two diseases had common changes in immune-related genes. The expression of innate immune response and response to virus-related genes increased significantly, while the expression of negative regulation of cell cycle-related genes decreased notably. In contrast, the expression of mitophagy regulation, chromatin binding and fatty acid metabolism-related genes showed distinct trends.

CONCLUSIONS

Stable differences and similarities between systemic sclerosis and lung cancer were revealed. In peripheral blood, enhanced innate immunity and weakened negative regulation of cell cycle may be the common mechanisms of the two diseases, which may be associated with the high risk of lung cancer in systemic sclerosis patients. On the other hand, the counter-regulated DEGs can be used as novelbiomarkers of pulmonary diseases. In addition, fat metabolism-related DEGs were consideredto be associated with clinical blood lipid data.

IPSE, a urogenital parasite-derived immunomodulatory molecule, suppresses bladder pathogenesis and anti-microbial peptide gene expression in bacterial urinary tract infection

BACKGROUND

Parasitic infections can increase susceptibility to bacterial co-infections. This may be true for urogenital schistosomiasis and bacterial urinary tract co-infections (UTI). We previously reported that this co-infection is facilitated by S. haematobium eggs triggering interleukin-4 (IL-4) production and sought to dissect the underlying mechanisms. The interleukin-4-inducing principle from Schistosoma mansoni eggs (IPSE) is one of the most abundant schistosome egg-secreted proteins and binds to IgE on the surface of basophils and mast cells to trigger IL-4 release. IPSE can also translocate into host nuclei using a nuclear localization sequence (NLS) to modulate host transcription. We hypothesized that IPSE is the factor responsible for the ability of S. haematobium eggs to worsen UTI pathogenesis.

METHODS

Mice were intravenously administered a single 25 μg dose of recombinant S. haematobium-derived IPSE, an NLS mutant of IPSE or PBS. Following IPSE exposure, mice were serially weighed and organs analyzed by histology to assess for toxicity. Twenty-four hours after IPSE administration, mice were challenged with the uropathogenic E. coli strain UTI89 by urethral catheterization. Bacterial CFU were measured using urine. Bladders were examined histologically for UTI-triggered pathogenesis and by PCR for antimicrobial peptide and pattern recognition receptor expression.

RESULTS

Unexpectedly, IPSE administration did not result in significant differences in urine bacterial CFU. However, IPSE administration did lead to a significant reduction in UTI-induced bladder pathogenesis and the expression of anti-microbial peptides in the bladder. Despite the profound effect of IPSE on UTI-triggered bladder pathogenesis and anti-microbial peptide production, mice did not demonstrate systemic ill effects from IPSE exposure.

CONCLUSIONS

Our data show that IPSE may play a major role in S. haematobium-associated urinary tract co-infection, albeit in an unexpected fashion. These findings also indicate that IPSE either works in concert with other IL-4-inducing factors to increase susceptibility of S. haematobium-infected hosts to bacterial co-infection or does not contribute to enhancing vulnerability to this co-infection.

Association of Schistosoma haematobium infection morbidity and severity on co-infections in pre-school age children living in a rural endemic area in Zimbabwe

Background

Individuals living in Schistosoma haematobium endemic areas are often at risk of having other communicable diseases simultaneously. This usually creates diagnostic difficulties leading to misdiagnosis and overlooking of schistosomiasis infection. In this study we investigated the prevalence and severity of coinfections in pre-school age children and further investigated associations between S. haematobium prevalence and under 5 mortality.

Methods

A community based cross-sectional survey was conducted in Shamva District, Zimbabwe. Using random selection, 465 preschool age children (1–5 years of age) were enrolled through clinical examination by two independent clinicians for the following top morbidity causing conditions: respiratory tract infections, dermatophytosis, malaria and fever of unknown origin. The conditions and their severe sequels were diagnosed as per approved WHO standards. S. haematobium infection was diagnosed by urine filtration and the children were screened for conditions common in the study area which included HIV, tuberculosis, malnutrition and typhoid. Data was analysed using univariate and multinomial regression analysis and relative risk (RR) calculated.

Results

Prevalence of S. haematobium was 35% (145). The clinical conditions assessed had the following prevalence in the study population: upper respiratory tract infection 40% (229), fever of unknown origin 45% (189), dermatophytosis 18% and malaria 18% (75). The odds of co-infections observed with S. haematobium infection were: upper respiratory tract infection aOR = 1.22 (95% CI 0.80 to 1.87), dermatophytosis aOR = 4.79 (95% CI 2.78 to 8.25), fever of unknown origin aOR = 10.63 (95% CI 6.48–17.45) and malaria aOR = 0.91 (95% CI 0.51 to1.58). Effect of schistosomiasis coinfection on disease progression based on the odds of the diseases progressing to severe sequalae were: Severe pneumonia aOR = 8.41 (95% CI 3.09–22.93), p < 0.0001, complicated malaria aOR = 7.09 (95% CI 1.51–33.39), p = 0.02, severe dermatophytosis aOR = 20.3 (95% CI 4.78–83.20):p = 0.03, and fever of unknown origin aOR = 1.62 (95%CI 1.56–4.73), p = 0.02.

Conclusion

This study revealed an association between schistosomiasis and the comorbidity conditions of URTI, dermatophytosis, malaria and FUO in PSAC living in a schistosomiasis endemic area. A possible detrimental effect where coinfection led to severe sequels of the comorbidity conditions was demonstrated. Appropriate clinical diagnostic methods are required to identify associated infectious diseases and initiate early treatment of schistosomiasis and co-infections in PSAC.

Clinical morbidity associated with Schistosoma haematobium infection in pre-school age children from an endemic district in Zimbabwe

OBJECTIVE

To investigate Schistosoma haematobium morbidity in infected pre-school age children and establish their disease burden.

METHODOLOGY

Pre-school age children (1-5 years) who were lifelong residents of the study area and had no other infections were included in the study. Participants underwent a physical examination with clinicians blinded to their infection status. Diagnosis of S. haematobium was by urine filtration.

RESULTS

The prevalence of S. haematobium was 35.1% (146/416). The clinical features observed in patients with Schistosoma haematobium were as follows: wheezes (morbidity attributable factor (AF = 93.9%), haematuria (AF = 92.6%), ascites (AF = 91.5%), atopy (AF = 76.9%), inguinal lymphadenopathy (AF = 68.4%), stunting (AF = 38.2), malnutrition (MUAC)(AF = 20%) and weight for height scales (AF = 5%). Schistosoma. haematobium infected children were at greater odds ratio of presenting with inguinal lymphadenopathy (AOR)=99.2(95% CI 24.2 to 854.5), wheezes in the chest (AOR = 35.4 95% CI 15.3 to 94.2), Distended abdomen with ascites (AOR = 23.9 95% CI 11.4 to 54), haematuria (AOR = 12.6 95% CI 11.6 to 14.1), atopy history (AOR = 5.6 95% CI 1.85 to 20.2), malnutrition (AOR = 2.3 95% CI 1.4 to 3.2) and stunting (AOR = 1.9 95% CI 1.1 to2.7).

CONCLUSION

The study is novel as it demonstrates for the first time clinical morbidity markers associated with S. haematobium infection in pre-school age children. Furthermore the study adds scientific evidence to the call for inclusion of pre-school age children in schistosomiasis control programmes. These morbidity markers highlight the need for early diagnosis and screening for S. haematobium in pre-school age children.

Change in schistosomiasis-related liver disease with repeated praziquantel treatment in school children in rural Zambia

Repeated praziquantel treatment for schistosomiasis is an effective method to reduce disease burden. Ultrasonographic methods were used to assess the severity of schistosoma mansoni-related liver disease and demonstrate improvement following treatment. We compared data from 733 children in 2010 and 972 children in 2018 to determine the effect of repeated praziquantel treatment on prevalence of liver disease. Three age groups were compared across three liver disease classifications (normal, mild, severe). From 2010 to 2018, there was a significant reduction in prevalence of severe liver disease in all age groups (P = 0.03 for 5-10 years, P < 0.001 for 11-15 years and 16-20 years). In both male and female students, the proportion having a normal liver significantly increased (P < 0.001) from 2010 to 2018, in the 11-15-year-olds and 16-20-year-olds, demonstrating that liver disease significantly reduced in these age groups. This study demonstrates a reduction in schistosomiasis-related morbidity with repeated praziquantel treatment.

Ultrasound evaluation of schistosomiasis-related morbidity among the Xakriabá people in the state of Minas Gerais, Brazil

Objective

To use ultrasound to investigate the morbidity related to schistosomiasis in the Xakriabá indigenous population.

Materials and Methods

This was a field-based census study conducted in the territory of the Xakriabá people. A total of 166 individuals were invited, and 148 (≤ 77 years of age) agreed to participate. Most participants underwent abdominal ultrasound, physical examination, and stool examination. Mann-Whitney U and chi-square tests were used for comparisons. We determined risk by calculating odds ratio (OR) and performed logistic regression analysis.

Results

Schistosoma mansoni eggs were found in 31 (26.7%) of the 116 stool samples examined, 22 (70.9%) of the 31 being from individuals 4-16 years of age. The median count was 144 eggs/g of feces (interquartile range, 264). Of the 105 participants examined with ultrasound, 68 (64.8%) had hepatomegaly (left lobe), 6 (5.7%) had splenomegaly, and 4 (3.8%) had portal hypertension. Egg-positive stool samples were more common in those with an enlarged left lobe (OR = 3.4; 95% confidence interval (CI): 1.1-11.2; p = 0.043). Periportal fibrosis was found in 30 participants (28.6%), of whom 9 (30%) had pattern C, 10 (33.3%) had pattern D, and 11 (36.7%) had pattern Dc. Age was the only independent risk factor for fibrosis (p = 0.007). Fibrosis was up to nine-fold more common in alcohol drinkers than in nondrinkers (OR = 9.28; 95% CI: 2.60-33.06; p < 0.001). Among the 138 participants in whom the clinical form was classified, the chronic hepatic form was identified in 54 (39.1%), of whom 32 (59.2%) were under 30 years of age and one (1.8%) was hepatosplenic.

Conclusion

Schistosomiasis in the Xakriabá population is characterized by a high frequency of egg-positive stool samples, predominantly in children/adolescents, and by chronic hepatic form in the young, especially among alcohol drinkers.

Schistosomiasis: Still a Cause of Significant Morbidity and Mortality

Tropical diseases remain severe threats to global health with acute or chronic debility. Public health issues are regularly monitored and reported by the WHO. Conditions with high prevalence and virulence such as Schistosomiasis or Malaria still need active treatment. Advances over the decades in the treatment and management of Schistosomiasis have reduced morbidity and mortality in patients. However, poverty, adverse environments, lack of education and awareness, with parasites and vectors that can thrive if uncontrolled, remain issues for the successful global eradication of Schistosomiasis. From the disease's discovery in 1850, the author relates historical details to its current status. Several countries previously affected, including Japan and Tunisia, have eliminated the disease while others seek the same goal. Africa remains the most severely affected continent with vulnerable women and children, although the infection persists in South America and the Far East of Asia as well. Realistic improvements for continuing health conditions are vogue and emphasized for those at risk or afflicted by the infection, illustrating success models of concerted efforts of extirpation. Constant proximity to infected water, with a parasite host, are hurdles in reducing exposure. Effective medication for acute treatment is available, and prophylaxis by vaccination is promising. Where endemic Schistosomiasis is prevalent, significant morbidity and mortality have far-reaching complications in multiple human organ systems, including irreversible pulmonary hypertension, renal, genitourinary, central nervous system conditions, and neoplasia. Two hundred and thirty million people are estimated to have contracted Schistosomiasis globally, with up to 700 million still at risk of infection, and 200,000 deaths occur annually. The disease may be more prevalent than thought after newer tests have shown increased sensitivity to pathological antigens. The author discusses infectivity risks, investigations, prognosis, treatment, and management, as well as morbidity and mortality.

The association between child Schistosoma spp. infections and morbidity in an irrigated rice region in Mali: A localized study

Background

Schistosomiasis is one of the neglected tropical diseases endemic to Mali. There has been insufficient investigation of the morbidity burden in highly endemic irrigated rice areas with the ongoing mass drug administration with praziquantel. In February 2005, a year after an initial mass drug administration in 2004, we performed the first cross-sectional survey of schistosomiasis in the Kokry-Bozo village in the Office du Niger rice irrigation region. In the fourteen years since this survey, there has been almost no research into schistosomiasis morbidity in Mali due to lack of funding. Therefore, the 2005 survey supplies near-baseline data for any future research into the treatment impacts in the area.

Methods

One hundred and ninety-four children aged 6–14 years from two schools were assessed for bladder pathology by ultrasound, and for anaemia and micro-haematuria by laboratory tests. Schistosoma eggs were examined microscopically in fresh stool and urine samples. Multivariate logistic regression analysis quantified the association of Schistosoma infections with anaemia, bladder pathology and micro-haematuria. Akaike’s information criterion was used to test the assumption of linear effects of infection intensity classes and used to compare across models.

Results

The overall prevalence of schistosomiasis in 189 school children was 97%; 17% (33/189) had a single infection (S. mansoni,13%, or S. haematobium, 4%) and 80% (156/189) were co-infected with S. mansoni and S. haematobium. The overall prevalence of S. mansoni with light infection was 27% (53/194), moderate infection was 24% (47/194) and heavy infection was 42% (81/194). Of the 194 of children investigated for S. haematobium 59% (114/194) had light infection and 26% (50/194) had heavy infection. No hookworm eggs were detected.

The level of abnormal bladder pathology was 18% (35/189) with the highest found in 10–14 year old children. The prevalence of anaemia was 91% (172/189) and was twice as likely to be associated (OR 2.0, 95% CI 1.1–3.9) with S. mansoni infections than in children without infection. As infection intensity with S. mansoni increased the risk of anaemia (OR 2.0, 95% CI 1.1–3.9) also increased. As infection intensity with S. haematobium increased bladder pathology (OR 2.4, 95%CI 1.3–4.5), haematuria (OR 6.7, 95%CI 3.3–13.6) and micro-haematuria increased (OR 2.4, 95%CI 1.3–4.5).

Conclusion

Our research contributes an important micro-geographical assessment of the heavy burden of schistosomiasis and associated morbidity in children who live in the rice irrigation regions. Our literature review found that there has been very limited research conducted on the impact of the treatment to control morbidity in the ON. Therefore, there is a need to do a comparable, but more extensive, study to identify any changes in morbidity and to indicate current requirements for the control programme. Our results from 2005 called for routine integration of iron supplementation, food fortification and diet diversification into the deworming program.

Schistosomiasis-associated pulmonary arterial hypertension: survival in endemic area in Brazil

•

The PHC registry equation accurately predicted survival in Sch-PAH patients.

•

Sch-PAH survival cannot be safely predicted using only validated clinical variables only.

•

Survival studies in endemic regions of Schistosomiasis are needed to establish the real prognosis of Sch-PAH in the world.

Background

The survival of schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) patients in endemic areas is unknown, but can be estimated using predictive equations.

Methods

We retrospectively analyzed all consecutive patients diagnosed with Sch-PAH referred to the Pronto SocorroCardiologico de Pernambuco between 2004 and 2010 using specific therapy and measured laboratory, diagnostic imaging, and baseline hemodynamic parameters. Observed and predicted survivals according to the National Institutes of Health (NIH) and Pulmonary Hypertension Connection (PHC) registry equations were compared by the Kaplan–Meier method, log-rank test and Cox proportional hazards model.

Results

Sixty-eight patients (47 [69.1%] women) observed for a mean of 3.1 years (range, 7–72 months), median survival was 74 months, and 42 (61.7%) survived. The sex and age distributions were similar for functional class I/II and III/IV patients. Hemodynamic abnormalities were severe: mean right atrial pressure, 12.6 ± 6.2 mmHg; mean pulmonary artery pressure, 60.3 ± 13.69 mmHg; pulmonary vascular resistance, 14.62 ± 7.04 Wood units; and cardiac index, 2.3 ± 0.8 L/min/m². The usual idiopathic PAH predictors were not prognostic in Sch-PAH patients. The 1-, 3- and 5-year survival rates were 92.1%, 75.2%, and 50.8%, respectively, and those estimatedby the NIH and PHC registry equations were 68%, 45% and 32% (p = 0.001), and 93%, 79% and 68% (p = 0.340), respectively.

Conclusions

Sch-PAH patients in endemic areas have severe hemodynamic profiles and reduced long-term survivaldespite treatment. The PHC registry equation may be a useful tool to estimate survival in Sch-PAH.

Recombinant Sj16 protein with novel activity alleviates hepatic granulomatous inflammation and fibrosis induced by Schistosoma japonicum associated with M2 macrophages in a mouse model

BACKGROUND

Potent granulomatous inflammation responses induced by schistosome eggs and resultant fibrosis are the primary causes of morbidity in schistosomiasis. Recombinant Sj16 (rSj16), a 16-kDa protein of Schistosoma japonicum produced in Escherichia coli, has been demonstrated to have novel immunoregulatory effects in vivo and in vitro. Thus, this study investigated the anti-inflammatory and anti-fibrotic effects of rSj16 treatment in S. japonicum-infected mice and demonstrated the immune modulation between the schistosome and the host.

METHODS

Schistosoma japonicum infected mice were treated with the rSj16 protein and Sj16 peptide at different time points post-infection to assess their efficacy at the optimal time point. Sj16 peptide and/or Praziquantel (PZQ) treatments were initiated at week 5 post-infection to compare the therapeutic efficacy of each regimen. Hepatic granulomatous inflammation, fibrosis and cytokine production (pro-inflammatory, Th1, Th2, Th17 and regulatory cytokines IL-10) were detected. Moreover, M2 macrophages were measured to illuminate the mechanisms of Sj16.

RESULTS

The rSj16 protein and Sj16 peptide had significant protective effects in S. japonicum-infected mice, as shown by decreased granuloma formation, areas of collagen deposition and inhibition of pro-inflammatory Th1, Th2 and Th17 cytokine production. These protective activities were more obvious when animals were treated with either the Sj16 protein or peptide at early stages post-infection. Interestingly, the combined treatment of PZQ and Sj16 was more effective and upregulated IL-10 production than administration of PZQ alone in infected mice. Furthermore, the Sj16 treatment alleviated the pathological effects associated with activated M2 macrophages.

CONCLUSIONS

This study demonstrates the anti-inflammatory and anti-fibrotic effects of rSj16 in schistosomiasis. Therefore, the combination of rSj16 with PZQ could be a viable and promising therapeutic strategy for schistosomiasis. In addition, this investigation provides additional information on schistosome-mediated immune modulation and host-parasite interactions.

Schistosoma and Other Relevant Helminth Infections in HIV-Positive Individuals-an Overview

For many years, researchers have postulated that helminthic infections may increase susceptibility to HIV, and that immune activation may have contributed to the extensive spread of HIV in sub-Saharan Africa. In the meantime, immunological studies have provided some evidence in support of this hypothesis, while cross-sectional clinical studies were able to further support the assumed association between HIV infection and selected helminthic co-infections. However, as many of the helminthic infections relevant to HIV-infected patients belong to the group of “neglected tropical diseases”, as defined by the World Health Organization, a certain lack of attention has inhibited progress in fully scaling up treatment and prevention efforts. In addition, despite the fact that the challenges of co-infections have preoccupied clinicians for over two decades, relevant research questions remain unanswered. The following review aims to provide a concise overview of associations between HIV and selected helminthic co-infections concerning aspects of HIV acquisition and transmission, clinical and immunological findings in co-infected individuals, as well as treatment and prevention efforts.

Superimposing a high-fat diet on Schistosoma mansoni infection affects renin-angiotensin system components in the mouse kidney

INTRODUCTION

The levels of the full-length form of the (pro)renin receptor (PRR), a component of the renin-angiotensin system (RAS), may be reduced in the membranes of kidneys in renal diseases. This study aimed to investigate the RAS components in the kidneys of mice submitted to a combination of a high-fat diet and Schistosoma mansoni infection.

METHODS

Female BALB/c mice were maintained on a control or high-fat diet from 3 weeks of age. After 10 weeks on the designated diets, half the mice in each group were infected with S. mansoni cercariae. The blood and kidneys were harvested 8 weeks after infection.

RESULTS

The high-fat diet increased the number of eggs in the feces and the number of adult worms in the mesenteric bed. Schistosoma mansoni infection reduced the plasma levels of glucose, triglycerides, and HDL cholesterol in the control and high-fat diet groups. In mice on the control diet, S. mansoni infection resulted in increased expression of IL-6 in the kidneys; however, in mice on the high-fat diet, the levels of IL-6 were reduced and those of superoxide anions were increased. The RAS components evaluated were ACE2, renin, PRR, AT1R, and AT2R, and the levels of PRR were found to be reduced in the kidneys of infected mice on the high-fat diet.

CONCLUSIONS

The finding regarding PRR is not yet clear. However, combining a high-fat diet and S. mansoni infection resulted in increased oxidative stress in the kidney that can aggravate hypertension as well as its associated complications.

Gallbladder schistosomiasis: rare but possible, a case report and review of the literature

After Malaria, schistosomiasis remains the most important tropical disease in large parts of the world. It affects mainly the colon and the urinary tract. The hepatic involvement is significantly frequent, particularly by the mansoni species. Still one of the extremely rare locations is the gallbladder. Our case is about a 51 year old woman from Tunisia, which is no longer considered an endemic country, with no particular medical history, underwent surgery for symptomatic cholelithiasis. She had a laparoscopic cholecystectomy. Post operative period was uneventful. Histology of the gallbladder showed fibrosis in the mucosa and schistosomal ova in the wall. As a conclusion we can see that due to the lack of specific clinical and radiological signs, the diagnosis of gallbladder schistosomiasis is established only after the histological examination.

Alterations in the lipid profiles and circulating liver enzymes in individuals infected by Schistosoma mansoni

INTRODUCTION

Portal hypertension and periportal fibrosis commonly occur in severe Schistosoma mansoni infection. Changes in lipid profile and elevated levels of circulating liver enzymes have also been described in infected individuals. The present study sought to assess the alterations in laboratory parameters associated with liver disorder in individuals infected by S. mansoni who visited a private routine laboratory service. Levels of circulating liver enzymes (gamma-glutamyl transferase [γ-GT], aspartate transaminase [AST], alanine transaminase [ALT], and alkaline phosphatase [ALP]) and a lipid panel (total cholesterol [COL], high-density lipoprotein [HDL], low-density lipoprotein [LDL], very low-density lipoprotein [VLDL], and triglycerides [TRI]) were evaluated in both infected and non-infected individuals and relative risk was used to measure associations.

METHODS

Data were collected for analysis from a total of 1,078 cases identified in 379,600 individuals who submitted samples to the Datalab Laboratory (Salvador, Bahia) between 2004 and 2008.

RESULTS

S. mansoni infection led to increased circulating levels of γ-GT in both women and men, AST (women), and ALP (men). S. mansoni infection was a protective factor against increased levels of TRI, CHO, and VLDL for individuals aged 19 years or older. The results of our analysis indicate that alterations in lipid metabolism and circulating liver enzymes in asymptomatic S. mansoni-infected individuals might be attributed to eggs lodged in the hepatic sinusoids.

CONCLUSIONS

Parasitological testing for S. mansoni should be indicated in endemic areas when this pattern of alterations is detected.

Young Adults in Endemic Areas: An Untreated Group in Need of School-Based Preventive Chemotherapy for Schistosomiasis Control and Elimination

Parasitologic surveys of young adults in college and university settings are not commonly done, even in areas known to be endemic for schistosomiasis and soil-transmitted helminths. We have done a survey of 291 students and staff at the Kisumu National Polytechnic in Kisumu, Kenya, using the stool microscopy Kato-Katz (KK) method and the urine point-of-care circulating cathodic antigen (POC-CCA) test. Based on three stools/two KK slides each, in the 208 participants for whom three consecutive stools were obtained, Schistosoma mansoni prevalence was 17.8%. When all 291 individuals were analyzed based on the first stool, as done by the national neglected tropical disease (NTD) program, and one urine POC-CCA assay (n = 276), the prevalence was 13.7% by KK and 23.2% by POC-CCA. Based on three stools, 2.5% of 208 participants had heavy S. mansoni infections (≥400 eggs/gram feces), with heavy S. mansoni infections making up 13.5% of the S. mansoni cases. The prevalence of the soil-transmitted helminths (STH: Ascaris lumbricoides, Trichuris trichiura and hookworm) by three stools was 1.4%, 3.1%, and 4.1%, respectively, and by the first stool was 1.4%, 2.4% and 1.4%, respectively. This prevalence and intensity of infection with S. mansoni in a college setting warrants mass drug administration with praziquantel. This population of young adults is ‘in school’ and is both approachable and worthy of inclusion in national schistosomiasis control and elimination programs.

Clinico-epidemiology, malacology and community awareness of Schistosoma mansoni in Haradenaba and Dertoramis kebeles in Bedeno district, eastern Ethiopia

Background:

Schistosoma mansoni is a major public health problem. Different studies reported unidentified sites in Ethiopia with variable prevalence and intensity, but there is no report from this study area.

Objective:

To assess the clinico-epidemiology, malacology, risk factors, and community awareness of S. mansoni in Haradenaba and Dertoramis kebeles in the Bedeno district, eastern Ethiopia.

Methods:

A cross-sectional study was conducted among 1011 study participants in 413 systematically selected households from Haradenaba and Dertoramis kebeles from 30 June 2016 to 30 July 2017. Data were collected by using pretested, structured questionnaires, clinical examinations, and stool examinations. Stool samples were processed by the Kato-Katz method and examined microscopically. Snails were collected by scooping from water contact points. Data were analyzed using SPSS, version 16 statistical software.

Result:

The overall prevalence of S. mansoni was 35.7%. Heavy-intensity infection was detected in 8.9% of the study participants. Results included: participants who were unaware about the possible source of infection (adjusted odds ratio: 2.95; 95% confidence interval: 1.25, 7.95), modes of transmission (adjusted odds ratio: 5.51; 95% confidence interval: 3.52, 12.51), prevention (adjusted odds ratio: 4.01; 95% confidence interval: 2.00, 8.75) about schistosomiasis/bilharziasis were more likely infected with S. mansoni than those who were aware. Participants who swim or bathe in the river were more likely infected with S. mansoni than those who do not (adjusted odds ratio: 6.41; 95% confidence interval: 3.15, 11.25). Biomphalaria pfeifferi snails were collected from all water bodies in Haradenaba and Dertoramis, but they did not shed schistosome cercaria in the laboratory.

Conclusion:

S. mansoni infection is found in high magnitude in these study areas, despite not being previously reported. A majority of the study participants had low awareness about the source of infection, mode of transmission, and prevention methods of schistosomiasis. Efforts should be made to improve community awareness about transmission and prevention of schistosomiasis.

Community knowledge, attitudes and practices related to schistosomiasis and associated healthcare-seeking behaviours in northern Côte d'Ivoire and southern Mauritania

Background

Among parasitic infections, schistosomiasis ranks second after malaria in terms of worldwide morbidity. Despite efforts to contain transmission, more than 230 million people are infected, of which 85% live in Sub-Saharan Africa. While the epidemiologic characteristics of schistosomiasis have been extensively studied across endemic settings, social factors have been paid less attention. The current study assesses community knowledge of schistosomiasis causes, transmission, signs, symptoms and prevention, as well as healthcare-seeking behaviours in two West African settings, with the aim of strengthening schistosomiasis control interventions.

Methods

From August 2014 to June 2015, we conducted two cross-sectional surveys in Korhogo, Côte d’Ivoire and Kaédi, Mauritania. We applied a questionnaire to collect quantitative data at the household level in Korhogo (n = 1456) and Kaédi (n = 1453). Focus group discussions (Korhogo: n = 32, Kaédi: n = 32) and participatory photography (photovoice) (Korhogo: n = 16, Kaédi: n = 16) were conducted within the communities to gather qualitative data. In addition, semi-structured interviews were used to discuss with key informants from control programmes, non-governmental organizations and health districts (Korhogo: n = 8, Kaédi: n = 7).

Results

The study demonstrated that schistosomiasis is not well known by the communities; 64.1% claimed to know the causes of the disease, but the reality is different. This knowledge is more from cultural than biomedical source. It was observed that social construction of the disease is different from the biomedical definition. In Korhogo, schistosomiasis was often associated with several other diseases, notably stomach ulcer and gonorrhoea. The populations believe that schistosomiasis is caused by exposure to goat or dog urine in the environment. In Kaédi, schistosomiasis is considered as a disease transmitted by environmenal elements such as sunshine and dirty water. In both settings, the care-seeking pathways were found to be strongly influenced by local customs and self-medication acquired from the informal sector.

Conclusions

This study revealed that knowledge about the aetiology, transmission, symptoms, prevention and treatment of schistosomiasis among the populations in Korhogo and Kaédi is based on their local culture. Deep-rooted habits could therefore pose a significant obstacle to the elimination of schistosomiasis.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0453-0) contains supplementary material, which is available to authorized users.

Schistosoma mansoni-Associated Morbidity among Preschool-Aged Children along the Shores of Lake Victoria in Uganda

Schistosoma mansoni causes morbidity in human beings, with the highest prevalence in rural sub-Saharan Africa. Prolonged S. mansoni infection with egg deposition in intestinal blood vessels leads to liver and spleen enlargement, and thus chronic morbidity. The objective of this study was to assess whether preschool-aged children develop severe S. mansoni-related morbidity. Parasitological, clinical, and ultrasonographic examinations were carried out in 916 preschool-aged children in five schistosomiasis-endemic districts (Bugiri, Buikwe, Jinja, Mayuge, and Namayingo) along the Lake Victoria shoreline in east-central Uganda. Anaemia and anthropometry measurements were also taken. Using the Kato-Katz technique on one stool sample collected on three consecutive days, 74.9% (686/916) were found infected with S. mansoni; the majority were lightly infected (57.9%), while 22.7% and 19.4% were moderately and heavily infected, respectively. The overall geometric mean intensity (GMI) of infected children was 294.2 eggs per gram faeces. Mayuge and Jinja districts had the highest (51.2%) and lowest (2.2%) number of infected children, respectively. Hookworm infection was found in 7.8% (71/916) of the children. Both liver and spleen were significantly more enlarged in the infected children than in the uninfected children (p < 0.0005), as measured by ultrasonography. Physical palpation of the spleen was more often detected in the uninfected children. A significantly (p < 0.0005) higher proportion of S. mansoni-positive children were anaemic (359/686; 52.3%) compared to the children who had no eggs in their stool samples (81/230; 35.2%). Schistosoma mansoni infection did not have any severe effect on the nutrition status of preschool-aged children. Neither infected nor uninfected children were found to be underweight or stunted. Liver fibrosis with distinct Symmer's 'pipe stems' was found in a few heavily-infected children (0.3%). In a linear multivariable regression analysis, age of the child, anaemia, liver fibrosis, and size of the left liver lobe were associated with S. mansoni intensity of infection (adjusted R² = 0.11; p < 0.0005). Our results demonstrate that S. mansoni-related morbidity does develop in children less than six years of age, and that older children (37⁻60 months) are at higher risk (regression coefficient 0.33; p <0.0005) compared to younger ones (12⁻36 months). We recommend that preschool-aged children be included in the target population for schistosomiasis mass treatment so as to prevent the childhood chronic form of schistosomiasis.

Decrease in Seminal HIV-1 RNA Load After Praziquantel Treatment of Urogenital Schistosomiasis Coinfection in HIV-Positive Men-An Observational Study

Background

Urogenital schistosomiasis due to Schistosoma hematobium infection is hypothesized to cause increased HIV-1 RNA shedding in semen in HIV co-infected men as result of chronic egg-induced inflammation in the prostate and the seminal vesicles. The effect of treatment with the antihelminthic agent praziquantel on seminal HIV-1 RNA load was assessed in this study.

Methods

HIV-1 RNA load was determined in blood plasma and semen at baseline and at 10-week follow-up. Praziquantel was administered at baseline and two weeks later.

Results

Eighteen HIV-positive men with S. haematobium co-infection were enrolled into the study. Status of antiretroviral therapy (ART): 6 ART-naïve and 12 ART-experienced. All participants became egg-negative in urine at follow-up. Among the ART-naïve men, the mean HIV-1 RNA load decreased by 0.32 log₁₀ copies per mL (4.41 vs 4.09) in blood plasma from baseline to follow-up, and in semen by 1.06 log₁₀ copies per mL (4.06 vs 3.00).

Conclusions

This study demonstrated a decline in seminal HIV-1 RNA load following praziquantel treatment of urogenital schistosomiasis infection in HIV-positive men. The finding needs further exploration in a larger randomized study targeting praziquantel as a supplementary preventive measure of sexual transmission of HIV-1 in S. haematobium endemic areas in sub-Saharan Africa.

Protective role of IL-22 against Schistosoma mansoni soluble egg antigen-induced granuloma in Vitro

The role of T helper-17 (Th17) lymphocytes in the regulation of Schistosoma mansoni soluble egg antigen (SEA)-induced granuloma is unknown. This study examined the effect of Th17 cytokines (IL-17 and IL-22) on granulocyte recruitment and functions during SEA-induced granuloma formation in vitro in Schistosoma-infected and noninfected individuals. Granulocytes were isolated from 27 Schistosoma-infected patients and 13 controls and were used for granuloma induction using SEA-conjugated polyacrylamide beads in the presence of Th17 cytokines. Granuloma index was assessed, and granulocyte mediators such as tumour necrosis factor (TNF-α), hydrogen peroxide (H2 O2 ) and nitric oxide (NO) were measured in the culture supernatant at the 7th day using enzyme-linked immunosorbent assay (ELISA). Schistosoma-infected patients had significant larger SEA-induced granuloma than controls. IL-17 (125 pg/mL) induced the optimum size for granuloma within 3-7 days. However, IL-22 at different concentrations up to 300 pg/mL had no effect on granuloma formation. Using both cytokines simultaneously, IL-22 suppressed the effect of IL-17 and prevented granuloma formation. IL-17 significantly decreased TNF-α, H2 O2 and NO levels in Schistosoma-infected individuals. In contrast, IL-22 increased TNF-α and H2 O2 levels. In conclusion, IL-17 accelerates SEA-induced granuloma formation and inhibits granulocytes functions in Schistosoma-infected patients, while IL-22 inhibited the granuloma formation, but enhanced granulocyte functions.

Urinary Schistosomiasis among Children in Murbai and Surbai Communities of Ardo-Kola Local Government Area, Taraba State, Nigeria

Background. This cross-sectional study was conducted to determine the prevalence, intensity of infection, and risk factors associated with urinary schistosomiasis among children in Murbai and Surbai communities of Ardo-Kola Local Government Area (LGA), Taraba State, Nigeria. Methods. Urine samples were analysed by the standard filtration technique using 10 ml syringe, Swinnex polypropylene filter holder (13 mm diameter), and polycarbonate membrane filters (12 μm porosity). Sociodemographic data and water contact activities were collated from children using structured questionnaires. Results. A point prevalence of 58.54% was reported out of the urine samples examined. Males were significantly more infected than their female counterparts (71.15% versus 43.66%, χ² = 89.12, p = 0.000). The age-related prevalence showed 6–10 and 11–15 years significantly infected with 78.70% and 73.02%, respectively (χ² = 89.12, p = 0.000). Light intensity of infection, 62.51%, was significantly higher than heavy intensity, 37.48%, among the infected children (χ² = 365.8, p = 0.000). Water contact activities such as fishing (OR = 4.01, CI = 3.04–5.61, p = 0.000), rice farming (OR = 4.01, CI = 2.96–5.36, p = 0.000), and dry season farming (OR = 4.78, CI = 3.68–6.22, p = 0.000) were the risk factors exposing children to infection in the area. Conclusion. There is an urgent need to undertake a large scale deworming control programme using praziquantel in the area.

The influence of trematode parasite burden on gene expression in a mammalian host

Background

Parasites can profoundly impact their hosts and are responsible for a plethora of debilitating diseases. To identify global changes in host gene expression related to parasite infection, we sequenced, assembled, and annotated the liver transcriptomes of Balb/cj mice infected with the trematode parasite Schistosoma mansoni and compared the results to uninfected mice. We used two different methodologies (i.e. de novo and reference guided) to evaluate the influence of parasite sequences on host transcriptome assembly.

Results

Our results demonstrate that the choice of assembly methodology significantly impacted the proportion of parasitic reads detected from the host library, yet the presence of non-target (xenobiotic) sequences did not create significant structural errors in the assembly. After removing parasite sequences from the mouse transcriptomes, we analyzed host gene expression under different parasite infection levels and observed significant differences in the associated immunologic and metabolic responses based on infection level. In particular, genes associated with T–helper type 1 (Th–1) and T–helper type 2 (Th–2) were up-regulated in infected mice whereas genes related to amino acid and carbohydrate metabolism were down-regulated in infected mice. These changes in gene expression scale with infection status and likely impact the evolutionary fitness of hosts.

Conclusions

Overall, our data indicate that a) infected mice reduce the expression of key metabolic genes in direct proportion to their infection level; b) infected mice similarly increase the expression of key immune genes in response to infection; c) patterns of gene expression correspond to the pathological symptoms of schistosomiasis; and d) identifying and filtering out non-target sequences (xenobiotics) improves differential expression prediction. Our findings identify parasite targets for RNAi or other therapies and provide a better understanding of the pathology and host immune repertoire involved in response to S. mansoni infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2950-5) contains supplementary material, which is available to authorized users.

Reduced Efficacy of Praziquantel Against Schistosoma mansoni Is Associated With Multiple Rounds of Mass Drug Administration

Background. Mass drug administration (MDA) with praziquantel is the cornerstone of schistosomiasis control in sub-Saharan Africa. The effectiveness of this strategy is dependent on the continued high efficacy of praziquantel; however, drug efficacy is rarely monitored using appropriate statistical approaches that can detect early signs of wane.

Methods. We conducted a repeated cross-sectional study, examining children infected with Schistosoma mansoni from 6 schools in Uganda that had previously received between 1 and 9 rounds of MDA with praziquantel. We collected up to 12 S. mansoni egg counts from 414 children aged 6–12 years before and 25–27 days after treatment with praziquantel. We estimated individual patient egg reduction rates (ERRs) using a statistical model to explore the influence of covariates, including the number of prior MDA rounds.

Results. The average ERR among children within schools that had received 8 or 9 previous rounds of MDA (95% Bayesian credible interval [BCI], 88.23%–93.64%) was statistically significantly lower than the average in schools that had received 5 rounds (95% BCI, 96.13%–99.08%) or 1 round (95% BCI, 95.51%–98.96%) of MDA. We estimate that 5.11%, 4.55%, and 16.42% of children from schools that had received 1, 5, and 8–9 rounds of MDA, respectively, had ERRs below the 90% threshold of optimal praziquantel efficacy set by the World Health Organization.

Conclusions. The reduced efficacy of praziquantel in schools with a higher exposure to MDA may pose a threat to the effectiveness of schistosomiasis control programs. We call for the efficacy of anthelmintic drugs used in MDA to be closely monitored.

The impact of schistosomes and schistosomiasis on murine blood coagulation and fibrinolysis as determined by thromboelastography (TEG)

Schistosomes are parasitic platyhelminths that currently infect over 200 million people and cause the chronic debilitating disease schistosomiasis. While these large intravascular parasites can disturb blood flow, surprisingly they do not appear to provoke thrombus formation around them in vivo. In order to determine if the worms can alter their local environment to impede coagulation, we incubated adult worms (50 pairs) in murine blood (500 µl) for 1 h at 37 °C and, using thromboelastography (TEG), we compared the coagulation profile of the blood with control blood that never contained worms. Substantial differences were apparent between the two profiles. Blood that had been exposed to schistosomes clotted more slowly and yielded relatively poor, though stable, thrombi; all TEG measures of blood coagulation (R, K, α-angle, MA, G and TMA) differed significantly between conditions. No fibrinolysis (as determined by LY30 and LY60 values) was detected in either case. The observed TEG profile suggests that the worms are acting as local anti-coagulants. Blood recovered from schistosome-infected mice, however, does not behave in this way. At an early time point post infection (4-weeks), the TEG profile of infected murine blood is essentially the same as that of control blood. However at a later time point (7-weeks) infected murine blood clots significantly faster than control blood but these clots also break down faster. The R, K, α-angle, and TMA measures of coagulation are all significantly different between the control versus infected mice as are the LY30 and LY60 values. This profile is indicative of a hypercoagulable state with fibrinolysis and is akin to that seen in human patients with advanced schistosomiasis.

Prevalence of Schistosoma mansoni Infection in Four Health Areas of Kisantu Health Zone, Democratic Republic of the Congo

Background. Schistosomiasis is a public health problem in Democratic Republic of the Congo but estimates of its prevalence vary widely. The aim of this study was to determine prevalence of Schistosoma mansoni infection and associated risk factors among children in 4 health areas of Kisantu health zone. Methods. A cross-sectional study was carried out in 4 health areas of Kisantu health zone. 388 children randomly selected were screened for S. mansoni using Kato Katz technique and the sociodemographic data was collected. Data were entered and encoded using software EpiData version 3.1. Analysis was performed using SPSS version 21 software. Results. The prevalence of S. mansoni was 26.5% (103); almost two-thirds (63) (61.2%) had light infection intensity. A significant association was found between S. mansoni infection and age (p = 0.005), educational level (p = 0.001), and practices of swimming/bathing (p < 0.001) and using water from river/lake/stream for domestic use (p < 0.001). Kipasa health area had high prevalence of schistosomiasis (64.6%) (64/99; 95% CI 54.4-74.0) compared to other health areas. Conclusion. Schistosoma mansoni infection still remains a public health problem in these areas. There is a need to promote health education and promote behavioral changes in children towards schistosomiasis.

Considering treatment of male genital schistosomiasis as a tool for future HIV prevention: a systematic review

OBJECTIVES

Male genital schistosomiasis (MGS) is a neglected manifestation of Schistosoma haematobium infection with ignored implications on reproductive health and a differential diagnosis to sexually transmitted infections in endemic regions. MGS may have associations with HIV transmission and acquisition, and treatment could be a neglected chance of HIV prevention. This review summarizes current knowledge on epidemiology, clinical manifestations, diagnosis and treatment of MGS as a hypothesized risk factor for HIV transmission. Future research areas of global interest are suggested.

METHODS

PubMed published literature was reviewed based on the MOOSE guidelines. All publications on MGS were included regardless of publication year and study design. Furthermore, all publications were searched for information on possible HIV association.

RESULTS

The 40 identified publications related to MGS were dominated by case reports and observational studies. No randomized clinical trials have been conducted to date, and very scant information related to possible associations with HIV transmission was presented.

CONCLUSIONS

Clinical, randomized studies and epidemiological studies covering the possible association between MGS and HIV are urgently needed. Furthermore, field diagnostic tools should be developed and future mass treatment programs should include adults to reduce morbidity and prevent HIV acquisition.

SYSTEMATIC REVIEW REGISTRATION NUMBER

CRD42015016252.

Mitochondrial dynamics in the mouse liver infected by Schistosoma mansoni

Mitochondrial dynamics is crucial for regulation of cell homeostasis. Schistosoma mansoni is one of the most common parasites known to cause liver disease. Mice infected by S. mansoni show acute symptoms of schistosomiasis after 8 weeks. Hence, in this study, we attempted to assess the direct effects of S. mansoni infection on mice liver, and to explore the expression of mitochondrial morphology, dynamics, and function. Our recent findings show that S. mansoni infection changes mitochondrial morphology and affects mitochondrial functions, which attenuates mitochondrial membrane potential and ATP generation. S. mansoni-infected mice increases mitochondrial numbers by upregulating of genes involved in mitochondrial biogenesis, including peroxisome proliferator-activated receptor c co-activator 1α (PGC1α) and mitochondrial transcription factor A (Tfam). This may promote mitochondria generation for accelerating the recovery of mitochondrial functions. Moreover, S. mansoni would disrupt mitochondrial dynamics including induced mitochondrial fission and promoted mitochondrial fragmentation in mice liver. More importantly, S. mansoni further stimulated upregulation both extrinsic and intrinsic apoptosis pathway in infected mice liver. The intrinsic pathway was triggered by cytochrome c release. Additionally, NFκB (nuclear factor-kappa B, p65) could play a protective role to inhibit apoptosis through reducing active caspase-3 expression. Therefore, our results confirmed the liver damage mechanism of experimental schistosomiasis in mice model.

Single Versus Double Dose Praziquantel Comparison on Efficacy and Schistosoma mansoni Re-Infection in Preschool-Age Children in Uganda: A Randomized Controlled Trial

BACKGROUND

Schistosoma mansoni infection is proven to be a major health problem of preschool-age children in sub-Saharan Africa, yet this age category is not part of the schistosomiasis control program. The objective of this study was to compare the impact of single and double dose praziquantel (PZQ) treatment on cure rates (CRs), egg reduction rates (ERRs) and re-infection rates 8 months later, in children aged 1-5 years living along Lake Victoria, Uganda.

METHODOLOGY/PRINCIPAL FINDINGS

Infected children (n= 1017) were randomized to receive either a single or double dose of PZQ. Initially all children were treated with a single standard oral dose 40 mg/kg body weight of PZQ. Two weeks later a second dose was administered to children in the double dose treatment arm. Side effects were monitored at 30 minutes to 24 hours after each treatment. Efficacy in terms of CRs and ERRs for the two treatments was assessed and compared 1 month after the second treatment. Re-infection with S. mansoni was assessed in the same children 8 months following the second treatment. CRs were non-significantly higher in children treated with two 40 mg/kg PZQ doses (85.5%; 290/339) compared to a single dose (83.2%; 297/357). ERRs were significantly higher in the double dose with 99.3 (95%CI: 99.2-99.5) compared with 98.9 (95%CI: 98.7-99.1) using a single dose, (P = 0.01). Side effects occurred more frequently during the first round of drug administration and were mild and short-lived; these included vomiting, abdominal pain and bloody diarrhea. Overall re-infection rate 8 months post treatment was 44.5%.

CONCLUSIONS

PZQ is efficacious and relatively safe to use in preschool-age children but there is still an unmet need to improve its formulation to suit small children. Two PZQ doses lead to significant reduction in egg excretion compared to a single dose. Re-infection rates with S. mansoni 8 months post treatment is the same among children irrespective of the treatment regimen.

Cx3cr1 deficiency in mice attenuates hepatic granuloma formation during acute schistosomiasis by enhancing the M2-type polarization of macrophages

Acute schistosomiasis is characterized by pro-inflammatory responses against tissue- or organ-trapped parasite eggs along with granuloma formation. Here, we describe studies in Cx3cr1^−/− mice and demonstrate the role of Cx3cr1 in the pathoetiology of granuloma formation during acute schistosomiasis. Mice deficient in Cx3cr1 were protected from granuloma formation and hepatic injury induced by Schistosoma japonicum eggs, as manifested by reduced body weight loss and attenuated hepatomegaly along with preserved liver function. Notably, S. japonicum infection induced high levels of hepatic Cx3cr1 expression, which was predominantly expressed by infiltrating macrophages. Loss of Cx3cr1 rendered macrophages preferentially towards M2 polarization, which then led to a characteristic switch of the host immune defense from a conventional Th1 to a typical Th2 response during acute schistosomiasis. This immune switch caused by Cx3cr1 deficiency was probably associated with enhanced STAT6/PPAR-γ signaling and increased expression of indoleamine 2,3-dioxygenase (IDO), an enzyme that promotes M2 polarization of macrophages. Taken together, our data provide evidence suggesting that CX3CR1 could be a viable therapeutic target for treatment of acute schistosomiasis.

Highlighted Article: A reduction in CX3CR1 signaling provides protection for mice against pro-inflammatory responses and hepatic granuloma formation during acute schistosomiasis.

Schistosoma haematobium infection and asymptomatic bacteriuria in young South African females

Schistosoma haematobium eggs can induce lesions in the urinary and genital tract epithelia, as eggs pass through or get trapped in the tissue. Local inflammatory reactions induced by S. haematobium eggs might affect the ability of bacteria to establish mucosal super-infection foci. S. haematobium infection and asymptomatic bacteriuria can both portray haematuria, proteinuria and leukocyturia. This shared set of proxy diagnostic markers could fuel routine misdiagnosis in S. haematobium endemic areas. Furthermore, S. haematobium infected individuals might be at a higher risk of contracting bacterial urinary tract infections, which could manifest either as symptomatic or asymptomatic bacteriuria. The aim of the current study was to explore whether schistosomal lesions are susceptible to super-infection by bacteria measured as asymptomatic bacteriuria. S. haematobium infection was determined by microscopy of urine samples. Furthermore, urine samples were tested with dipslides for asymptomatic bacteriuria and with dipsticks for haematuria, proteinuria and leukocytes. We found no association between asymptomatic bacteriuria and S. haematobium infection in a sample of 1040 female primary and high school students from a schistosomiasis endemic area in KwaZulu-Natal, South Africa. Furthermore, it was demonstrated that asymptomatic bacteriuria is not a bias for use of micro-haematuria as a proxy diagnostic measure for S. haematobium infection in this population.

Circulating antigen tests and urine reagent strips for diagnosis of active schistosomiasis in endemic areas

BACKGROUND

Point-of-care (POC) tests for diagnosing schistosomiasis include tests based on circulating antigen detection and urine reagent strip tests. If they had sufficient diagnostic accuracy they could replace conventional microscopy as they provide a quicker answer and are easier to use.

OBJECTIVES

To summarise the diagnostic accuracy of: a) urine reagent strip tests in detecting active Schistosoma haematobium infection, with microscopy as the reference standard; and b) circulating antigen tests for detecting active Schistosoma infection in geographical regions endemic for Schistosoma mansoni or S. haematobium or both, with microscopy as the reference standard.

SEARCH METHODS

We searched the electronic databases MEDLINE, EMBASE, BIOSIS, MEDION, and Health Technology Assessment (HTA) without language restriction up to 30 June 2014.

SELECTION CRITERIA

We included studies that used microscopy as the reference standard: for S. haematobium, microscopy of urine prepared by filtration, centrifugation, or sedimentation methods; and for S. mansoni, microscopy of stool by Kato-Katz thick smear. We included studies on participants residing in endemic areas only.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, assessed quality of the data using QUADAS-2, and performed meta-analysis where appropriate. Using the variability of test thresholds, we used the hierarchical summary receiver operating characteristic (HSROC) model for all eligible tests (except the circulating cathodic antigen (CCA) POC for S. mansoni, where the bivariate random-effects model was more appropriate). We investigated heterogeneity, and carried out indirect comparisons where data were sufficient. Results for sensitivity and specificity are presented as percentages with 95% confidence intervals (CI).

MAIN RESULTS

We included 90 studies; 88 from field settings in Africa. The median S. haematobium infection prevalence was 41% (range 1% to 89%) and 36% for S. mansoni (range 8% to 95%). Study design and conduct were poorly reported against current standards. Tests for S. haematobium Urine reagent test strips versus microscopyCompared to microscopy, the detection of microhaematuria on test strips had the highest sensitivity and specificity (sensitivity 75%, 95% CI 71% to 79%; specificity 87%, 95% CI 84% to 90%; 74 studies, 102,447 participants). For proteinuria, sensitivity was 61% and specificity was 82% (82,113 participants); and for leukocyturia, sensitivity was 58% and specificity 61% (1532 participants). However, the difference in overall test accuracy between the urine reagent strips for microhaematuria and proteinuria was not found to be different when we compared separate populations (P = 0.25), or when direct comparisons within the same individuals were performed (paired studies; P = 0.21).When tests were evaluated against the higher quality reference standard (when multiple samples were analysed), sensitivity was marginally lower for microhaematuria (71% vs 75%) and for proteinuria (49% vs 61%). The specificity of these tests was comparable. Antigen assayCompared to microscopy, the CCA test showed considerable heterogeneity; meta-analytic sensitivity estimate was 39%, 95% CI 6% to 73%; specificity 78%, 95% CI 55% to 100% (four studies, 901 participants). Tests for S. mansoni Compared to microscopy, the CCA test meta-analytic estimates for detecting S. mansoni at a single threshold of trace positive were: sensitivity 89% (95% CI 86% to 92%); and specificity 55% (95% CI 46% to 65%; 15 studies, 6091 participants) Against a higher quality reference standard, the sensitivity results were comparable (89% vs 88%) but specificity was higher (66% vs 55%). For the CAA test, sensitivity ranged from 47% to 94%, and specificity from 8% to 100% (4 studies, 1583 participants).

AUTHORS' CONCLUSIONS

Among the evaluated tests for S. haematobium infection, microhaematuria correctly detected the largest proportions of infections and non-infections identified by microscopy.The CCA POC test for S. mansoni detects a very large proportion of infections identified by microscopy, but it misclassifies a large proportion of microscopy negatives as positives in endemic areas with a moderate to high prevalence of infection, possibly because the test is potentially more sensitive than microscopy.

Pathological aspects of bovine focal fibrogranulomatous proliferative panniculitis (Lechiguana)

Lechiguana is a disease of cattle caused by an interaction between Dermatobia hominis warble and the bacteria Manheimia granulomatis. It is characterized by subcutaneous swellings that grow rapidly and result in death after 3 to 8 months. The objective of this paper was to investigate some vascular and fibrogenic changes of the disease at different lesion stages by histochemical and immunohistochemical techniques. A peculiar histopathological aspect observed during a proliferative phase (before treatment) was the intense vasculitis, described as degenerative and fibro-proliferative, expressed by the oncogene p53, possibly caused by the presence of bacteria in close contact with enthotelial cells, along with dense accumulations of lymphoid cells around venules. The synthesis of collagen fibers during the development of Lechiguana lesions assume a structural aspect of star arrangement with fiber radiation centers that gradually interconnect to design the Extracellular Matrix (ECM) framework, seen by Confocal Laser Scanning Microscopy (CSLM). Angiogenesis was the most characteristic finding in both proliferative and regressive stages as seen by the immunohistochemical expression of cytoskeleton proteins and von Willebrand (Factor VIII-Related Antigen). Additionally, in all tissues samples, active ECM elements like Metalloproteinases (MMPs), Tissue Inhibitors Metalloproteinases (TIMP) and Fibronectin (FN) were mainly associated to vessels structures. The extraordinary regression of exuberant granulation tissue after treatment is undoubtedly associated to the maintenance of the vascular components observed during the regressive phase.

Schistosomes versus platelets

Schistosomes are parasitic platyhelminths that currently infect >200million people and cause the chronic debilitating disease schistosomiasis. While these large intravascular parasites can disturb blood flow, they do not appear to activate platelets and provoke thrombus formation. Host-interactive tegumental molecules have been proposed to be important in this regard. For example, tegumental apyrase, SmATPDase1 can degrade the platelet-activating molecule ADP in the extracellular environment. The parasites themselves can produce prostaglandins (or may induce prostaglandin production by host cells) which could inhibit platelet aggregation. Additional tegumental proteins have been proposed to impede the coagulation cascade and to promote fibrinolysis. Platelets have been shown to be directly toxic to schistosomes. Platelets recovered from infected rats are able to kill larval parasites in culture and platelets obtained at later times post-infection are generally better at killing. Even platelets from uninfected rats can rapidly kill larval schistosomes if first exposed to a variety of activators (such as: serum from infected rats, the IgE fraction of that serum, C-reactive protein, cytokines (TNFα or TNFβ)). Passive transfer of stimulated platelets can protect rats against a challenge schistosome infection. Cytokines (TNFα, TNFβ, IFNγ or IL-6) have been shown to similarly promote normal human platelet killing of schistosomes in vitro. Platelet antimicrobial effector molecules (e.g. platelet microbicidal proteins) may mediate such killing. While platelets can be protective against schistosomes following infection of humans and mice, platelet numbers decline (but not so in the non-permissive rat host) and coagulopathy becomes more apparent as schistosome-induced pathology increases.

High Schistosoma mansoni disease burden in a rural district of western Zambia

Schistosoma mansoni disease is endemic in most parts of rural Zambia, and associated complications are common. We conducted a cross-sectional study among 754 people in rural communities of Kaoma District, western Zambia to determine the burden of S. mansoni infection and associated morbidity. Parasitology and ultrasonography assessments were conducted on consenting participants. The overall prevalence of S. mansoni infection and geometric mean egg count (GMEC) were 42.4% (304) and 86.6 eggs per gram (95% confidence interval = 75.6-99.6), respectively. Prevalence was highest in the age group of 15-19 years old (adjusted prevalence ratio = 1.70, P = 0.017). S. mansoni-related portal fibrosis was detected in 26% of the participants screened. Participants above 39 years old were 2.93 times more likely to have fibrosis than the 7-9 years old age group (P = 0.004). The study highlights the high burden of S. mansoni disease in this area and calls for immediate interventions to avert complications associated with the disease.

Hepatobiliary Schistosomiasis

Schistosomiasis is an ancient parasitic disease that has afflicted Egyptians since the time of the pharaohs. The disease is caused by lodged schistosome eggs in the host liver, evoking an immune response and leading in some patients to the development of hepatic granuloma and fibrosis. Here, we review the epidemiology, immunopathogenesis, and clinical profile of schistosomiasis. This information may aid in the development of more efficacious treatments and improved disease prognosis.

Schistosome apyrase SmATPDase1, but not SmATPDase2, hydrolyses exogenous ATP and ADP

Schistosomes are parasitic worms that can live in the bloodstream of their vertebrate hosts for many years. It has been proposed that the worms impinge on host purinergic signalling by degrading proinflammatory molecules like ATP as well as prothrombotic mediators like ADP. This capability may help explain the apparent refractoriness of the worms to both immune elimination and thrombus formation. Three distinct ectoenzymes, expressed at the host-exposed surface of the worm's tegument, are proposed to be involved in the catabolism of ATP and ADP. These are alkaline phosphatase (SmAP), phosphodiesterase (SmNPP-5), and ATP diphosphohydrolase (SmATPDase1). It has recently been shown that only one of these enzymes-SmATPDase1-actually degrades exogenous ATP and ADP. However, a second ATP diphosphohydrolase homolog (SmATPDase2) is located in the tegument and has been reported to be released by the worms. It is possible that this enzyme too participates in the cleavage of exogenous nucleotide tri- and di-phosphates. To test this hypothesis, we employed RNA interference (RNAi) to suppress the expression of the schistosome SmATPDase1 and SmATPDase2 genes. We find that only SmATPDase1-suppressed parasites are significantly impaired in their ability to degrade exogenously added ATP or ADP. Suppression of SmATPDase2 does not appreciably affect the worms' ability to catabolize ATP or ADP. Furthermore, we detect no evidence for the secretion or release of an ATP-hydrolyzing activity by cultured parasites. The results confirm the role of tegumental SmATPDase1, but not SmADTPDase2, in the degradation of the exogenous proinflammatory and prothrombotic nucleotides ATP and ADP by live intravascular stages of the parasite.

Clinico-epidemiological study of Schistosomiasis mansoni in Waja-Timuga, District of Alamata, northern Ethiopia

Background

Intestinal schistosomiasis, caused by digenetic trematodes of the genus Schistosoma, is the most prevalent water related disease that causes considerable morbidity and mortality. Although prevalence of Schistosoma mansoni infection has been reported for the present study area, earlier studies have not estimated intensity of infections in relation to periportal fibrosis, which would have been crucial for epidemiological and clinical evaluations. Hence, a community based cross sectional study was conducted from December 2011 to March 2012 to assess prevalence of infection and schistosomal periportal fibrosis in Waja-Timuga, northern Ethiopia.

Methods

In a cross sectional study involving 371 randomly selected individuals, fresh stool samples were collected and processed by the Kato-Katz method and examined microscopically. Ultrasonography was used to determine status of schistosomal periportal fibrosis and to detect hepatomegaly and/or splenomegaly. Serum was collected for assay of hepatic activity. Statistical analysis was performed using STATA 11 statistical soft ware. P-value <0.05 was reported as statistically significant.

Results

The prevalence of S.mansoni infection was 73.9%, while the prevalence of schistosomal periportal fibrosis was 12.3% and mean intensity of infection was 234 eggs per gram of stool. Peak prevalence and intensity of S.mansoni infection was documented in the age range of 10–20 years. Among the study individuals, hepatomegaly was recorded in 3.7% and splenomegaly was recorded in 7.4% of the study individuals. Similarly, among the study individuals who had definite periportal fibrosis, 5.9% had elevated liver enzyme levels.

Conclusion

The high prevalence of Schistosoma mansoni infection and schistosomal periportal fibrosis observed in the study area calls for a periodic deworming program to reduce disease, morbidity and transmission. Preventive chemotherapy complemented with other control measures is highly required for sustainable control of schistosomiasis in the study area.

Schistosome tegumental ecto-apyrase (SmATPDase1) degrades exogenous pro-inflammatory and pro-thrombotic nucleotides

Schistosomes are parasitic worms that can survive in the hostile environment of the human bloodstream where they appear refractory to both immune elimination and thrombus formation. We hypothesize that parasite migration in the bloodstream can stress the vascular endothelium causing this tissue to release chemicals alerting responsive host cells to the stress. Such chemicals are called damage associated molecular patterns (DAMPs) and among the most potent is the proinflammatory mediator, adenosine triphosphate (ATP). Furthermore, the ATP derivative ADP is a pro-thrombotic molecule that acts as a strong activator of platelets. Schistosomes are reported to possess at their host interactive tegumental surface a series of enzymes that could, like their homologs in mammals, degrade extracellular ATP and ADP. These are alkaline phosphatase (SmAP), phosphodiesterase (SmNPP-5) and ATP diphosphohydrolase (SmATPDase1). In this work we employ RNAi to knock down expression of the genes encoding these enzymes in the intravascular life stages of the parasite. We then compare the abilities of these parasites to degrade exogenously added ATP and ADP. We find that only SmATPDase1-suppressed parasites are significantly impaired in their ability to degrade these nucleotides. Suppression of SmAP or SmNPP-5 does not appreciably affect the worms' ability to catabolize ATP or ADP. These findings are confirmed by the functional characterization of the enzymatically active, full-length recombinant SmATPDase1 expressed in CHO-S cells. The enzyme is a true apyrase; SmATPDase1 degrades ATP and ADP in a cation dependent manner. Optimal activity is seen at alkaline pH. The Km of SmATPDase1 for ATP is 0.4 ± 0.02 mM and for ADP, 0.252 ± 0.02 mM. The results confirm the role of tegumental SmATPDase1 in the degradation of the exogenous pro-inflammatory and pro-thrombotic nucleotides ATP and ADP by live intravascular stages of the parasite. By degrading host inflammatory signals like ATP, and pro-thrombotic signals like ADP, these parasite enzymes may minimize host immune responses, inhibit blood coagulation and promote schistosome survival.

Association of Schistosoma mansoni-specific IgG and IgE antibody production and clinical schistosomiasis status in a rural area of Minas Gerais, Brazil

Background

Studies in murine models and human populations have indicated that the collagen-rich granulomatous response against parasite eggs trapped in the liver is associated with the development of severe hepatosplenic schistosomiasis, characterized by periportal fibrosis and portal hypertension. The role of the humoral response in parasite susceptibility has been well established, but its participation in disease severity remains poorly understood. In this work, we evaluated the relationship between parasite-reactive IgE and IgG levels and schistosomiasis morbidity in infected patients with similar parasite burdens.

Methodology/Principal Findings

Ninety-seven Schistosoma mansoni-infected individuals were subjected to clinical examination and abdominal ultrasound analysis. IgG reactivity and IgE concentration against Schistosoma mansoni soluble egg antigens (SEA) and adult worm antigen preparation (SWAP) were evaluated by ELISA assay. Multivariable linear regression models were used to evaluate the relationship between parasite-reactive antibodies and the co-variables investigated. The study population showed low parasite burden (median 30 eggs/g feces), constant re-infection, and signs of fibrosis was detected in more than 30% of individuals. Most infected individuals showed IgG reactivity, and the median concentrations of IgE anti-SEA and anti-SWAP antibodies were 1,870 and 1,375 ng/mL, respectively. There was no association between parasite burden and antibody response or any parameter of disease severity. However, IgG anti-SWAP level was positively associated with morbidity parameters, such as spleen size and thickness of portal vein at the entrance and secondary branch. In contrast, the data also revealed independent inverse correlations between concentration of parasite-reactive IgE and gallbladder wall thickness, a marker of fibrosis in schistosomiasis.

Conclusions/Significance

The data indicate that IgG anti-SWAP is positively associated with severe schistosomiasis, independently of parasite burden, while high production of parasite-specific IgE is associated with mild disease in the human population. Antibody profiles are good correlates for schistosomiasis severity and could be tested as biomarkers of disease severity.

Schistosomiasis as a rare cause of recurrent acute appendicitis - A case report

INTRODUCTION

We are presenting a case of schistosomiasis in a 41 year old lady who presented with right iliac fossa pain for 3 years. The pain worsened and the frequency increased in the last 3 months prior to referral. The ultrasound was unremarkable. Her bowel habits were normal and there was no vomiting. There was no blood in the stool or in the urine.

PRESENTATION OF CASE

The abdomen was soft except on deep palpation. There was slight tenderness in the right lower quadrant. A repeat ultrasound was unremarkable. The full blood count was within the normal range. A diagnosis of recurrent acute appendicitis was made and an interval appendicectomy was performed.

DISCUSSION

Histopathology results revealed schistosomiasis of the appendix. There was no acute inflammation but there was fibrous obliteration of the distal lumen of the appendix and reactive lymphoid hyperplasia.

CONCLUSION

This is the first case in a country with relatively clean drinking water. There are no irrigation schemes but there are seasonal rivers and streams. The patient admits to swimming in these streams during childhood. Clinical features of schistosomiasis were not elicited.

New insights into the molecular epidemiology and population genetics of Schistosoma mansoni in Ugandan pre-school children and mothers

Significant numbers of pre-school children are infected with Schistosoma mansoni in sub-Saharan Africa and are likely to play a role in parasite transmission. However, they are currently excluded from control programmes. Molecular phylogenetic studies have provided insights into the evolutionary origins and transmission dynamics of S. mansoni, but there has been no research into schistosome molecular epidemiology in pre-school children. Here, we investigated the genetic diversity and population structure of S. mansoni in pre-school children and mothers living in lakeshore communities in Uganda and monitored for changes over time after praziquantel treatment. Parasites were sampled from children (<6 years) and mothers enrolled in the longitudinal Schistosomiasis Mothers and Infants Study at baseline and at 6-, 12- and 18-month follow-up surveys. 1347 parasites from 35 mothers and 45 children were genotyped by direct sequencing of the cytochrome c oxidase (cox1) gene. The cox1 region was highly diverse with over 230 unique sequences identified. Parasite populations were genetically differentiated between lakes and non-synonymous mutations were more diverse at Lake Victoria than Lake Albert. Surprisingly, parasite populations sampled from children showed a similar genetic diversity to those sampled from mothers, pointing towards a non-linear relationship between duration of exposure and accumulation of parasite diversity. The genetic diversity six months after praziquantel treatment was similar to pre-treatment diversity. Our results confirm the substantial genetic diversity of S. mansoni in East Africa and provide significant insights into transmission dynamics within young children and mothers, important information for schistosomiasis control programmes.

Many pre-school children in sub-Saharan Africa are infected with the parasite Schistosoma mansoni, which causes intestinal schistosomiasis. However, there has been no work published on the molecular epidemiology of Schistosoma in children under six or the role that these children play in parasite transmission. We analysed the genetic structure of parasite populations collected from mothers and young children living on the shores of Lakes Albert and Victoria in Uganda. Parasite populations were different at the two lakes indicating that there is little flow of parasite genes between the lakes. We were surprised to discover a large amount of genetic variation in parasites sampled from both children and mothers, suggesting that genetic variation is not directly related to duration of exposure to infested water. In addition, we found some evidence that young children are involved in S. mansoni transmission. The substantial genetic variation of S. mansoni in young children suggests that these parasites could be operating as a source of a variety of genetic traits, including drug susceptibility. Overall our findings offer significant insights into population genetics of S. mansoni in pre-school children and their mothers and provide important information for effective control of intestinal schistosomiasis.

Schistosoma mansoni-related morbidity in a low-prevalence area of Brazil: a comparison between egg excretors and seropositive non-excretors

In areas where there is a low prevalence of schistosomiasis mansoni, faecal examination is a relatively insensitive method of detection and infected people may also be missed because most show only mild morbidity. In such settings, serology may be a more useful diagnostic tool than microscopy. In the present study, the clinical and biochemical characteristics of individuals who were stool-positive for Schistosoma mansoni eggs were compared with those of individuals, from the same low-prevalence area of Brazil, who were stool-negative but seropositive for the parasite. Overall, 269 subjects were checked both for schistosome eggs in their faeces (using Kato-Katz smears and Lutz sedimentation) and for anti-S. mansoni IgG in their sera (using an ELISA). Although 128 (48%) of these subjects were found seropositive, only 26 (10%) were found to be egg excretors and two of the egg excretors were seronegative. Compared with the seropositive egg-negatives, the egg excretors had significantly higher frequencies of fatigue, melaena, jaundice and swelling of the abdomen. The egg excretors also had higher frequencies of hepatomegaly (20% v. 16%) and splenomegaly (4% v. 1%). In both groups of subjects, mean concentrations of serum proteins and haemoglobin and mean leucocyte counts were in the normal range whereas most blood concentrations of alanine aminotransferase and many of those of aspartate aminotransferase were slightly elevated. Although the egg excretors tended to have low-intensity infections, it seems possible that the seropositive nonexcretors had even milder infections that could not be detected by faecal examination. The high frequency of cure observed when the egg excretors were given praziquantel at 40 mg/kg (94%) is probably another indication that most had light infections when they were treated.