Hepatic and intestinal schistosomiasis: review

Clinical mortality risk factors of variceal upper gastrointestinal bleeding in a Malagasy surgical intensive care unit

BACKGROUND

Variceal upper gastrointestinal bleeding is a dreadful complication of portal hypertension with a significant morbidity and mortality. Different prognostic scores can be used. However, in the local context of Madagascar, the completion of paraclinical investigations can be delayed by the limited financial means of patients. Hence, determining clinical mortality risk factors of variceal upper gastrointestinal bleeding could be interesting. The aim of the study was to evaluate the clinical mortality risk factors of variceal gastrointestinal bleeding (VUGIB).

METHOD

An observational, cohort retrospective study was conducted over an 8-year period (2010-2017), at the surgical intensive care unit of the J.R. Andrianavalona University Hospital, Antananarivo, in patients admitted for VUGIB confirmed by upper gastrointestinal endoscopy and whose clinical examination was performed at admission. The primary endpoint was intensive care unit (ICU) mortality. Univariate analysis and multivariate logistic regression analysis were performed to identify risk factors for ICU mortality, with OR defining odds ratio. A p value <0.05 was considered significant.

RESULTS

1920 patients were admitted for gastrointestinal bleeding of any digestive causes; the source of bleeding was variceal in 269 patients (14%). The predominantly male population (sex ratio = 2.5), aged 47.1 ± 13.7 years was mostly American Society of Anesthesiologists (ASA) 1 classification (58.4%). In 56.5% of patients, the gastrointestinal bleeding had not occurred before. The mortality rate was 16.0%. Three major clinical factors of mortality were identified: previous endoscopic band variceal ligation (OR = 12.57 [2.18-72.58], p = 0.005), tachycardia >120 bpm (OR = 2.91 [1.04-8.14], p = 0.041), and ascites (OR = 3.80 [1.85-7.81], p < 0.001).

CONCLUSION

Upper gastrointestinal bleeding may be life-threatening. The mortality scores are certainly useful; however, the identification of clinical factors is interesting in countries like Madagascar, pending the results of paraclinical investigations.

Rare cause of right iliac fossa pain in a UK patient

A 62-year-old Asian man presented with a 3-month history of right iliac fossa pain which had progressively worsened over the last 3 weeks. All blood parameters were found to be unremarkable except for mildly elevated erythrocyte sedimentation rate. CT imaging demonstrated thickening of the ascending colon and caecum. Colonoscopic biopsies showed submucosal granulomas with features suggestive of schistosomiasis and parasite serology was positive for Schistosoma antibodies. He was treated with praziquantel and showed subsequent symptomatic and radiological improvement. However, he represented nearly 2 years later and underwent a right hemicolectomy for small bowel obstruction. The resected bowel showed an inflammatory caecal mass and a terminal ileal adenocarcinoma.

Anatomical MRI and [18F]FDG PET/CT imaging of Schistosoma mansoni in a NMRI mouse model

Schistosomiasis represents one of the most devastating worm parasitosis in the world. Current diagnostic methods are insufficient to determine the infection grade and the disease related organ damage. We herein investigated whether discrimination of infection grade and its correlation to liver damage could be accurately performed by multimodal imaging in a mouse model of Schistosoma mansoni infection. Therefore, groups of uninfected and infected mice underwent MRI and [¹⁸F]FDG PET/CT imaging. Anatomical MRI images were used for liver volumetry and for quantification of hepatic granulomas. For PET/CT images a volume of interest based analyses were employed to calculate the [¹⁸F]FDG uptake in liver, portal vein, spleen and abdomen. Herein, we demonstrate that the combined use of [¹⁸F]FDG-PET/CT and MRI represents an appropriate diagnostic tool for Schistosoma mansoni infection, but fails to discriminate the infection grade and the linked organ damage. Only the splenic [¹⁸F]FDG uptake in the 25 cercariae group (5.68 ± 0.90%ID/cc) and 50 cercariae group (4.98 ± 1.43%ID/cc) was significantly higher compared to the control group (2.13 ± 0.69%ID/cc). Nevertheless, future multimodal imaging studies with new radiopharmaceuticals could build a highly sensitive and specific basis for the diagnosis and evaluation of organ damage of schistosomiasis.

In vivo assessment of the antischistosomal activity of curcumin loaded nanoparticles versus praziquantel in the treatment of Schistosoma mansoni

Schistosomiasis is a serious parasitic infection affecting millions worldwide. This study aimed to explore the anti-schistosomal activity of curcumin and curcumin loaded gold-nanoparticles (Cur-GNPs) with or without praziquantel (PZQ). We used six groups of the C57BL/6 mice in which five groups were infected with Schistosoma Mansoni (S. mansoni) cercariae and exhibited, separately, to different treatment regimens of curcumin, curcumin loaded nanoparticle, and PZQ, in addition to one untreated group which acts as a control. Mice were sacrificed at the 8th week where both worms and eggs were counted in the hepatic and porto-mesenteric vessels in the liver and intestine, respectively, in addition to a histopathological examination of the liver granuloma. Curcumin caused a significant reduction in the worms and egg count (45.45%) at the 3rd week. A significant schistosomicidal effect of PZQ was found in all groups. Cur-GNPs combined with PZQ 97.4% reduction of worm burden in the 3rd week and the highest reduction in the intestinal and hepatic egg content, as well, besides 70.1% reduction of the granuloma size. The results suggested the curcumin in combination with PZQ as a strong schistosomicidal regimen against S. mansoni as it alters the hematological, biochemical, and immunological changes induced.

Large bowel obstruction secondary to schistosomiasis-related colonic stricture

•

Schistosomiasis can manifest as non-obstructive polypoid lesions due to deposition of schistosomal eggs.

•

Obstructive lesions, such as fibrotic strictures, secondary to the infectious sequelae of schistosomiasis are rare.

•

Although schistosomiasis can be diagnosed on imaging and laboratory tests, there is no conclusive method of ruling out a malignancy.

•

Praziquantel is a safe and effective treatment for schistosomiasis, and prevents future sequela of the parasitic infection.

•

Surgical resection provides definitive treatment resulting in symptom resolution while ruling out a neoplastic etiology.

Introduction

Intestinal involvement of schistosomiasis uncommonly involves the formation of non-obstructive polypoid lesions; however, obstructing fibrotic stenoses and strictures secondary to chronic infection are extremely rare with only nine reported cases in the literature.

Presentation of case

An 85-year-old Southeast Asian female originating from the Philippines presents with a one-day history of obstructive symptoms in the setting of chronic constipation over the past four months. Subsequent CT imaging and colonoscopy biopsy revealed a nodular cecal mural wall thickening with chronic inflammation and a single Schistosoma egg. Despite treatment with praziquantel, and medical optimization the patient did not improve. Additionally, a malignancy as the underlying cause of obstruction could not be ruled out as such, she had a right hemicolectomy. Final pathology confirmed the diagnosis of intestinal submucosal schistosomiasis causing fibrotic stenosis.

Conclusion

Obstructing lesions including fibrotic stenoses secondary to Schistosomiasis infection can be managed safely with medical co-morbidity optimization when possible, treatment with Praziquantel and surgical resection of the involved area of colon. Given the risk of malignancy and the inability to clinically distinguish between infectious and neoplastic processes, surgical management is recommended.

Bevacizumab as a potential anti-angiogenic therapy in schistosomiasis: A double-edged, but adjustable weapon

AIM

Investigating the anti-angiogenic effect of bevacizumab on chronic schistosomiasis mansoni in a trial to hinder the Schistosome-induced angiogenesis and porto-systemic shunting complications.

METHODS

The immunohistochemical expression of CD34, VEGF-R1, PCNA and α-SMA (angiogenesis markers) was analysed in the lung, liver and gastrointestinal junctions of chronic S mansoni infected mice after intraperitoneal injection of bevacizumab. The effect of prolonged administration of bevacizumab with praziquantel was also assessed through parasitic load, protective index, granuloma and fibrous tissue evaluation.

RESULTS

A regression in the vascular activity and microvascular density was observed in the infected mice after receiving bevacizumab. They had a significantly less VEGF-R1, PCNA, CD-34 and α-SMA expression in comparison to the infected untreated mice. The least tissue egg count was reported in mice received bevacizumab for 6 weeks (Mean = 27 120). However, they had persistent liver granulomas, and massively amalgamated fibrosis. Interestingly, the least faecal egg and tissue worms counts (Mean = 112, 13.4), and the highest protection index (39.26) were reported in mice received bevacizumab for 3 weeks, with marked granuloma, and fibrous tissue resolution.

CONCLUSIONS

Bevacizumab has a promising protective effect against the Schistosoma-induced angiogenesis. As an adjuvant to praziquantel, it is important to adjust the appropriate duration of administration that achieves the best schistosomicidal effect without impeding granuloma and fibrous tissue resolution.

Intravital imaging of host-parasite interactions in organs of the thoracic and abdominopelvic cavities

Infections with protozoan and helminthic parasites affect multiple organs in the mammalian host. Imaging pathogens in their natural environment takes a more holistic view on biomedical aspects of parasitic infections. Here, we focus on selected organs of the thoracic and abdominopelvic cavities most commonly affected by parasites. Parasitic infections of these organs are often associated with severe medical complications or have health implications beyond the infected individual. Intravital imaging has provided a more dynamic picture of the host-parasite interplay and contributed not only to our understanding of the various disease pathologies, but has also provided fundamental insight into the biology of the parasites.

Morbidity associated with Schistosoma mekongi and concurrent helminth infection in Lao People's Democratic Republic

In 2006, some 7 years after the halt of a multi-year schistosomiasis control programme, a study was conducted in the southern part of Lao People's Democratic Republic to determine the morbidity associated with Schistosoma mekongi and concurrent helminth infection. In two S. mekongi-endemic districts, Khong and Mounlapamok, 640 individuals aged 9-40 years were randomly selected. Two stool samples were obtained from each participant and subjected to the Kato-Katz technique for helminth diagnosis. Morbidity was assessed by clinical examination and abdominal ultrasonography. Multiple logistic regression analysis was employed to relate S. mekongi infection with morbidity indicators. In Khong district, S. mekongi prevalence was 13-fold higher than in Mounlapamok district (57.7% vs. 4.4%, p < 0.001). Likewise, we observed significantly more often palpated hepatomegaly (15.5% vs. 5.4%) and splenomegaly (9.6% vs. 0.4%). Abdominal ultrasonography revealed that, in Khong district, liver and spleen morbidity occurred more frequently (e.g., enlarged left liver lobe: 89.2% vs. 68.7%, p < 0.001). Single species infection with S. mekongi was associated with enlarged peri-portal vein (adjusted odds ratio (aOR) 47.7, 95% confidence interval (CI) 4.2-85.7, p = 0.002), as was S. mekongi-Opisthorchis viverrini co-infection (aOR 2.2, 95% CI 1.1-4.5, p = 0.020). In conclusion, our study shows that in 2006, several years after the halt of the Lao schistosomiasis control programme that emphasised preventive chemotherapy, S. mekongi infection again had reached high prevalence rates. Infection with S. mekongi was associated with substantial hepatosplenic morbidity. Schistosomiasis control measures were re-instigated in 2010. In view of the ultimate goal to eliminate schistosomiasis, rigorous surveillance and public health responses tailored to the social-ecological settings and long-term programme commitment are warranted.

Synthesis and Bioactivity of Phthalimide Analogs as Potential Drugs to Treat Schistosomiasis, a Neglected Disease of Poverty

The neglected tropical disease, schistosomiasis, is caused by trematode blood flukes of the Schistosoma genus and infects approximately 200 million people worldwide. With just one partially effective drug available for disease treatment, new drugs are urgently needed. Herein, a series of 47 phthalimide (Pht) analogues possessing high-value bioactive scaffolds (i.e., benzimidazole and 1,2,3,-triazoles) was synthesized by click-chemistry. Compounds were evaluated for anti-schistosomal activity in culture against somules (post-infective larvae) and adults of Schistosoma mansoni, their predicted ADME (absorption, distribution, metabolism, and excretion) properties, and toxicity vs. HepG2 cells. The majority showed favorable parameters for surface area, lipophilicity, bioavailability and Lipinski score. Thirteen compounds were active at 10 µM against both somules and adults (6d, 6f, 6i–6l, 6n–6p, 6s, 6r’, 6t’ and 6w). Against somules, the majority caused degeneracy and/or death after 72 h; whereas against adult parasites, five compounds (6l, 6d, 6f, 6r’ and 6s) elicited degeneracy, tegumental (surface) damage and/or death. Strongest potency against both developmental stages was recorded for compounds possessing n-butyl or isobutyl as a linker, and a pentafluorophenyl group on triazole. Apart from five compounds for which anti-parasite activity tracked with toxicity to HepG2 cells, there was apparently no toxicity to HepG2 cells (EC₅₀ values ≥50 µM). The data overall suggest that phthaloyl-triazole compounds are favorable synthons for additional studies as anti-schistosomals.

Effects of programmed cell death protein 10 on the Schistosoma japonicum female reproductive system

This study aimed to investigate the effects of programmed cell death protein 10 (PCDP10) on the female reproductive system of Schistosoma japonicum, one of the major infectious agents of schistosomiasis. We found that PCDP10 was widely distributed in the integument, the worm parenchymal area, and the vitellarium of the female worm, but was localized to a lesser extent in the ovary and testicles. RNAi experiments successfully achieved gene knockdown, and the ultrastructural morphology of the adult reproductive organs was observed. The results demonstrated that, compared with those of the negative control group, the number of cortical granules around oocytes decreased and the number of immature oocyte cells increased. Fusion of yolk globules occurred, and the number and the diameter of yolk droplets decreased significantly. Real-time PCR showed that the expression of yolk glands reached its peak before ovulation and then decreased. The TUNEL assay results showed that apoptosis in the RNAi group was significantly higher than that in the negative control group. These results suggested that SjPCDP10 plays an important role in the female reproductive system. In conclusion, PCD10 is involved in oocyte growth and development, especially in eggshell formation, which may provide a reference for further elucidating the molecular mechanism of PCDP10 involved in egg formation and embryo development in Schistosoma japonicum.

Crystal structures of Triosephosphate Isomerases from Taenia solium and Schistosoma mansoni provide insights for vaccine rationale and drug design against helminth parasites

Triosephosphate isomerases (TPIs) from Taenia solium (TsTPI) and Schistosoma mansoni (SmTPI) are potential vaccine and drug targets against cysticercosis and schistosomiasis, respectively. This is due to the dependence of parasitic helminths on glycolysis and because those proteins elicit an immune response, presumably due to their surface localization. Here we report the crystal structures of TsTPI and SmTPI in complex with 2-phosphoglyceric acid (2-PGA). Both TPIs fold into a dimeric (β-α)₈ barrel in which the dimer interface consists of α-helices 2, 3, and 4, and swapping of loop 3. TPIs from parasitic helminths harbor a region of three amino acids knows as the SXD/E insert (S155 to E157 and S157 to D159 in TsTPI and SmTPI, respectively). This insert is located between α5 and β6 and is proposed to be the main TPI epitope. This region is part of a solvent-exposed 3₁₀–helix that folds into a hook-like structure. The crystal structures of TsTPI and SmTPI predicted conformational epitopes that could be used for vaccine design. Surprisingly, the epitopes corresponding to the SXD/E inserts are not the ones with the greatest immunological potential. SmTPI, but not TsTPI, habors a sole solvent exposed cysteine (SmTPI-S230) and alterations in this residue decrease catalysis. The latter suggests that thiol-conjugating agents could be used to target SmTPI. In sum, the crystal structures of SmTPI and TsTPI are a blueprint for targeted schistosomiasis and cysticercosis drug and vaccine development.

Because of the worldwide prevalence of schistosomiasis and cysticercosis, it is critical to develop drugs and vaccines against their causative agents. The glycolytic enzyme triosephosphate isomerase (TPI) is a dual-edged sword against diseases caused by parasitic helminths. This is because helminths heavily depend on glycolysis for energy and because the surface localization exhibited by TPIs that elicits an immune response against those organisms. Here we provide the crystal structures TPIs from Taenia solium and Schistosoma mansoni as a first step for vaccine and drug design. As a proof of concept we found that modifications in the single solvent exposed cysteine of TPI from S. mansoni decreases catalysis, making this enzyme a novel target against schistosomiasis.

Immunofluorescent Localization of Proteins in Schistosoma mansoni

Immunofluorescence allows the detection, visualization, and localization of proteins by using the ability of antibodies to firmly bind to specific antigens. Proteins must be accessible to thorough interaction with the specific antibodies. Different immune evasion mechanisms of parasites are directed to hamper or prevent access of antibodies to critical proteins or virulence factors. The blood fluke Schistosoma mansoni would not survive a day in the host blood capillaries if antibodies were able to readily bind to proteins located at the surface and mediate its attrition and demise by the complement system and/or the FcγR- or FcαR-bearing leukocytes. The worm surface is the area of parasite-host interaction and the route to critical nutrients, but is selectively permeable, allowing access of nutrient molecules but not host antibodies. Gentle procedures, which, however, are not commonly in use in vivo, are required to increase the permeability of the parasite outer membrane shield to just allow access of specific antibodies and identify and localize the proteins at the apical surface. Robust methods involving acetone, methanol, and Triton X-100 treatment lead to disintegration of the dual lipid bilayer cover with exposure of the proteins located in the tegument beneath. Internal proteins may not be accessed except following cryostat or paraffin sectioning. Accordingly, vaccine-induced specific antibodies to the apical surface or tegument proteins are unable to harm intact parasites. Specific antibodies to surface membrane proteins may only add to the action of administered or endo schistosomicides via acceleration of killing and interference with repair of severely and lightly impacted parasites, respectively. Therefore, careful immunofluorescent localization of S. mansoni proteins is important for devising the different control strategies against infection.

Preventive CTLA-4-Ig Treatment Reduces Hepatic Egg Load and Hepatic Fibrosis in Schistosoma mansoni-Infected Mice

Background

Hepatic fibrosis and granuloma formation as a consequence of tissue entrapped eggs produced by female schistosomes characterize the pathology of Schistosoma mansoni infection. We have previously shown that single-sex infection with female schistosomes mitigates hepatic fibrosis after secondary infection. This was associated with an increased expression of cytotoxic T-lymphocyte-associated protein-4 (CTLA-4), known as a negative regulator of T cell activation. Based on these findings, we hypothesized that administration of agonistic CTLA-4-Ig (Belatacept) is capable to prevent and/or treat hepatic fibrosis during schistosomiasis.

Methods

Mice were infected with 50 S. mansoni cercariae and CTLA-4-Ig, or appropriated control-Ig was administered for 4 weeks. Preventive treatment started 4 weeks after infection, before onset of egg production, and therapeutic treatment started 8 weeks after infection when hepatic fibrosis was already established.

Results

When given early after infection, livers of CTLA-4-Ig-treated mice showed significantly reduced collagen deposition and decreased expression of profibrotic genes in comparison to controls. In addition, administration of CTLA-4-Ig suppressed the inflammatory T cell response in infected mice. If therapy was started at a later time point when fibrogenesis was initiated, CTLA-4-Ig had no impact on hepatic fibrosis.

Conclusion

We could demonstrate that an early preventive administration of CTLA-4-Ig suppresses effector T cell function and therefore ameliorates liver fibrosis. CTLA-4-Ig administration after onset of egg production fails to treat hepatic fibrosis.

Analysis of CT characteristics in the diagnosis of Schistosoma japonicum associated appendicitis with clinical and pathological correlation: a diagnostic accuracy study

PURPOSE

To clarify unique non-contrast CT (NCCT) characteristics for early recognition of Schistosomal associated appendicitis (SAA) differentiating from Non-schistosomal associated appendicitis (NSA).

MATERIAL AND METHODS

Clinical and pathological data of 50 cases with SAA and 60 cases with NSA who underwent emergency appendectomy were retrospectively compared to pre-surgical NCCT features such as direct and indirect signs of acute appendicitis as well as appendicoliths, colon calcifications as diagnostic criteria. Statistical methods such as Chi-square (χ²), t-tests, Principal component analysis (PCA), Binary Logistic regression (LR) and Factor Analysis (FA) were utilized to observe differences and isolate recognizable CT features of SAA. Pre and post hoc diagnostic performance of all criteria was calculated as sensitivity, specificity, and the Odds Ratio (OR).

RESULTS

Age > 50 years, diameter > 13 mm, pneumatosis, peri appendiceal abscess, focal wall defect, perforation; Orbital, linear and point types of appendicular wall calcifications; sigmoid colon and cecal curvilinear calcifications were observed as unique characteristics with a sensitivity of 84-95% and specificity of 91-98% in predicting SAA by OR of 6.2 times. Pre and post hoc hypothetical analysis did not show any significance for all other factors.

CONCLUSION

Factors such as elderly age, CT features such as larger appendicular diameter, appendicular wall calcifications along with sigmoid colon, and cecal calcifications, signs of perforation or abscess are characteristic for early recognition of SAA.

Vaccination against the digestive enzyme Cathepsin B using a YS1646 Salmonella enterica Typhimurium vector provides almost complete protection against Schistosoma mansoni challenge in a mouse model

Schistosoma mansoni threatens hundreds of millions of people in >50 countries. Schistosomulae migrate through the lung and adult worms reside in blood vessels adjacent to the intestinal mucosa. Current candidate vaccines aren’t designed to elicit a mucosal response. We have repurposed an attenuated Salmonella enterica Typhimurium strain (YS1646) to produce such a vaccine targeting Cathepsin B (CatB), a digestive enzyme important for parasite survival. Promoter-Type 3 secretory signal pairs were screened for protein expression in vitro and transfected into YS1646 to generate candidate vaccine strains. Two strains were selected for in vivo evaluation (nirB_SspH1 and SspH1_SspH1). Female C57BL/6 mice were immunized twice, 3 weeks apart, using six strategies: i) saline gavage (control), ii) the ‘empty’ YS1646 vector orally (PO) followed by intramuscular (IM) recombinant CatB (20μg IM rCatB), iii) two doses of IM rCatB, iv) two PO doses of YS1646-CatB, v) IM rCatB then PO YS1646-CatB and vi) PO YS1646-CatB then IM rCatB. Serum IgG responses to CatB were monitored by ELISA. Three weeks after the second dose, mice were challenged with 150 cercariae and sacrificed 7 weeks later to assess adult worm and egg burden (liver and intestine), granuloma size and egg morphology. CatB-specific IgG antibodies were low/absent in the control and PO only groups but rose substantially in other groups (5898-6766ng/mL). The highest response was in animals that received nirB_SspH1 YS1646 PO then IM rCatB. In this group, reductions in worm and intestine/liver egg burden (vs. control) were 93.1% and 79.5%/90.3% respectively (all P < .0001). Granuloma size was reduced in all vaccinated groups (range 32.9–52.8 x10³μm²) and most significantly in the nirB_SspH1 + CatB IM group (34.7±3.4 x10³μm²vs. 62.2±6.1 x10³μm²: vs. control P < .01). Many eggs in the vaccinated animals had abnormal morphology. Targeting CatB using a multi-modality approach can provide almost complete protection against S. mansoni challenge.

Schistosomiasis is a parasitic disease that affects over 250 million people worldwide and over 800 million are at risk of infection. Of the three main species, Schistosoma mansoni is the most widely distributed and is endemic in the Caribbean, South America, and Africa. It causes a chronic disease with severe negative effects on quality of life. Mass drug administration of praziquantel is the only available course of action due to a current lack of vaccines. However, praziquantel does not protect from reinfection. Therefore, a vaccine would be beneficial as a long-term solution to reduce morbidity and transmission of the disease. Our group has repurposed the attenuated YS1646 strain of Salmonella Typhimurium as an oral vaccine vector for the digestive enzyme Cathepsin B of S. mansoni. Oral vaccination followed by an intramuscular dose of recombinant Cathepsin B lead to significant reductions in parasite burden in mice. These animals had the highest titers in serum IgG and intestinal IgA antibodies. This multimodal vaccination approach also elicited both Th1 and Th2 cytokines as seen by the increases in IFNγ and IL-5. Finally, vaccinated mice had reductions in granuloma size along with a higher proportion of morphologically-abnormal eggs. This work demonstrates that a YS1646-based, multimodality, prime-boost immunization schedule can provide nearly complete protection against S. mansoni in a well-established murine model.

Metabolic Programming of Macrophages: Implications in the Pathogenesis of Granulomatous Disease

Metabolic reprogramming is rapidly gaining appreciation in the etiology of immune cell dysfunction in a variety of diseases. Tuberculosis, schistosomiasis, and sarcoidosis represent an important class of diseases characterized by the formation of granulomas, where macrophages are causatively implicated in disease pathogenesis. Recent studies support the incidence of macrophage metabolic reprogramming in granulomas of both infectious and non-infectious origin. These publications identify the mechanistic target of rapamycin (mTOR), as well as the major regulators of lipid metabolism and cellular energy balance, peroxisome proliferator receptor gamma (PPAR-γ) and adenosine monophosphate-activated protein kinase (AMPK), respectively, as key players in the pathological progression of granulomas. In this review, we present a comprehensive breakdown of emerging research on the link between macrophage cell metabolism and granulomas of different etiology, and how parallels can be drawn between different forms of granulomatous disease. In particular, we discuss the role of PPAR-γ signaling and lipid metabolism, which are currently the best-represented metabolic pathways in this context, and we highlight dysregulated lipid metabolism as a common denominator in granulomatous disease progression. This review therefore aims to highlight metabolic mechanisms of granuloma immune cell fate and open up research questions for the identification of potential therapeutic targets in the future.

Immunoinformatics Prediction of Epitope Based Peptide Vaccine Against Schistosoma Mansoni Fructose Bisphosphate Aldolase Protein.. [DOI: 10.1101/755959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Schistosoma Mansonirepresents an important tropical disease that can cause schistosomiasis mostly in Africa and Middle East with high mortality rates. Moreover, no vaccine against it exists. This study predicts an effective epitope-based vaccine against Fructose 1,6 Bisphosphate Aldolase (FBA) enzyme of Schistosoma Mansoni using immunoinformatics approaches. FBA is important for production of energy required for different schistosome activities and survival. The sequences were retrieved from NCBI and several prediction tests were conducted to analyze possible epitopes for B-cell, T-cell MHC class I and II. Tertiary structure of the most promising epitopes was obtained. Two epitopes showed high binding affinity for B-cells, while four epitopes showed high binding affinity for MHCI and MHCII. The results were promising to formulate a vaccine with more than 99.5% population coverage. We hope that these promising epitopes serves as a preventive measure for the disease in the future and recommend invivo and invitro studies.

Impact of chronic schistosomiasis and HBV/HCV co-infection on the liver: current perspectives

Schistosomiasis is a public health problem in many countries. Its prevalence is increasing annually; the current infection rate is one in 30 individuals. The WHO reported that at least 206.4 million people all over the world required preventive treatments for schistosomiasis in 2016. Chronic schistosomiasis, hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infection are common in countries where schistosomiasis is endemic. The effects of the hepatotropic virus co-infection may modify the Th2-dominated granulomatous phase of schistosomal infection. These viruses induce a strong-specific T cell response, with infiltration of large numbers of specific interferon-γ-producing CD8+ cells into the liver. The outcome of liver diseases depends on the underlying causes, host immune response and concomitant infections. Co-infection of schistosomiasis with HBV/HCV infection causes advanced liver disease and worsens the outcome, especially with higher viral load titers, which increase the mortality rate through an increased incidence of liver cirrhosis and hepatocellular carcinoma. The exposure risk for HBV in patients with HCV and schistosomiasis was two and half times greater than that in CHC patients without schistosomiasis. Finally, chronic schistosomiasis and HBV/HCV co-infection have serious effects on liver pathology. Co-infection accelerates the progression of liver disease and leads to advanced liver diseases and liver failure.

Effect of omega-3 fatty acids administered as monotherapy or combined with artemether on experimental Schistosoma mansoni infection

Schistosomiasis is on the top list of endemic diseases in sub-Saharan Africa. Praziquantel is the drug of choice for treatment of human schistosomiasis. Yet, the sole dependence on the drug raises concerns about the potential for increased drug resistance, which would subsequently result in searching for alternative preventive chemotherapy options, ideally among natural compounds. Therefore, we conducted this work to assess the effect of omega-3 polyunsaturated fatty acids [(ω-3) PUFAs] monotherapy or combined therapy with artemether (ART) against Schistosoma mansoni infection in a mouse model. A total of 42 mice were divided into 4 groups and infected with 50 ± 5 S. mansoni cercariae for 10 weeks. Mice were treated orally with either (ω-3) PUFAs as 273 mg/ kg, 4 times/ week throughout the experiment, ART as a single dose of 400 mg/ kg, 3 weeks post-infection, or combined ART + (ω-3) PUFAs using the same respective treatment regimen, while infected untreated mice were served as controls. The study explored that combined administration of (ω-3) PUFAs and ART has the best schistosomicidal efficacy as it significantly reduced liver and spleen indices, worm count, egg burdens, and granulomas count as well as diameter. Besides, the combined regimen was associated with a significant decrease in both hepatic nitric oxide and serum interleukin-4 level. The results highlighted the possibility of using (ω-3) PUFA combined with ART as a novel anti-schistosomal combination therapy. However, further researches should be conducted to clarify the possible synergistic mechanism/s between the two natural compounds.

Systemic schistosomiasis and large bowel perforation: An unexpected surgical urgency. Report of a case and literature review

In the presence of suggestive clinical picture (high eosinophil count and multiple CT scan granuloma-like lesions), schistosomiasis should be taken into account in case of suspected bowel perforation even if common risk factors are not identified through anamnesis.

Schistosomiasis and associated iron-deficiency anaemia presenting decades after immigration from sub-Saharan Africa

Chronic schistosomiasis and its intestinal manifestations can lead to anaemia. However, schistosomiasis resulting in anaemia is rare in the UK. This report aims to raise awareness of schistosomiasis in immigrants to the UK and prevent missed diagnosis.

Schistosome infection and its effect on pulmonary circulation

Schistosomiasis is the most common parasitic disease associated with pulmonary hypertension. It induces remodelling via complex inflammatory processes, which eventually produce the clinical manifestation of pulmonary hypertension. The pulmonary hypertension shows clinical signs and symptoms that are not distinguishable from other forms of pulmonary arterial hypertension.

Schistosoma mansoni infection and risk factors among the fishermen of Lake Hawassa, southern Ethiopia

Schistosomiasis is a neglected tropical parasitic disease caused by different species of genus Schistosoma. Schistosoma mansoni causes a severe intestinal parasitic infection of high public and medical importance in Ethiopia. This study aimed to determine the prevalence of, and risk factors for, S. mansoni infection among the fishermen of Lake Hawassa, southern Ethiopia, using a cross-sectional study design. A total of 243 fishermen were selected from the Hawassa Town Fishermen Association's list in 2013. Data on socio-demographic characteristics and risk factors were collected from the fishermen using semi-structured questionnaires. Stool samples were collected and processed using the Kato-Katz thick smear technique. The overall prevalence of S. mansoni among the fishermen was 29.21% and the mean intensity of infection was 158.88 eggs per gram (EPG). The overall prevalence of intestinal helminths, including S. mansoni, was 69.54%. Similar prevalences of S. mansoni were recorded in age groups 15-19, 20-24 and 25-29 years: 31.82%, 31.75% and 31.94%, respectively. Fishermen who swam a minimum of once a week in Lake Hawassa were 2.92 times (95% CI: 1.554, 5.502) more likely to have acquired S. mansoni infection than those who swam in the lake less than once a week. The results indicate moderate endemicity of S. mansoni infection among the fishermen of Lake Hawassa. These fishermen could be a potentially high-risk group for S. mansoni infection and might be responsible for the transmission of infection to other segments of the community visiting the lake for recreation. Moreover, a high prevalence of soil-transmitted helminths (STHs) was recorded among the fishermen. Integrated prevention and control strategies for schistosomiasis and STHs by different sectors are needed to tackle this problem.

In vitro effect of curcumin on Schistosoma species viability, tegument ultrastructure and egg hatchability

Schistosomiasis remains a severe problem of public health in developing countries. The development of resistance to praziquantel (PZQ) has justified the search for new alternative chemotherapies with new formulations, more effective, and without adverse effects. Curcumin (CUR), the major phenolic compound present in rhizome of turmeric (Curcuma longa L.), has been traditionally used against various diseases including parasitic infections. Here, the antischistosomal activity of CUR (50-500 μM), evaluated in parallel against S. mansoni and S. haematobium adult worms, appeared significant (P < 0.05 to < 0.0001) in a time- and dose-dependent manner. Two h incubation with CUR (500 μM) caused 100% irreversible killing of both schistosomal species. CUR (250 μM) caused the death of S. haematobium and S. mansoni worms after 2 h and 4 h, respectively. As CUR concentration decreases (50 μM), all coupled adult worms were separated into individual male and female but the worms remained viable up to 4 h. Scanning and transmission electron microscopy revealed that S. haematobium are more sensitive than S. mansoni to CUR schistosomicidal effects. In support, CUR was found to affect the antigenicity of surface membrane molecules of S. haematobium, but not S. mansoni. Of importance, CUR significantly (P < 0.05 to < 0.0001) affected S. mansoni eggs hatchability and viability, a ground for its use in chemotherapy of schistosomiasis mansoni and japonicum because of its increased bioavailability in the gastrointestinal tract. The data together emphasize that CUR is a promising potential schistosomicidal drug.

WIPO Re:Search-A Platform for Product-Centered Cross-Sector Partnerships for the Elimination of Schistosomiasis

Schistosomiasis is an acute and chronic disease that affects over 200 million people worldwide, and with over 700 million people estimated to be at risk of contracting this disease, it is a pressing issue in global health. However, research and development (R&D) to develop new approaches to preventing, diagnosing, and treating schistosomiasis has been relatively limited. Praziquantel, a drug developed in the 1970s, is the only agent used in schistosomiasis mass drug administration (MDA) campaigns, indicating a critical need for a diversified therapeutic pipeline. Further, gaps in the vaccine and diagnostic pipelines demonstrate a need for early-stage innovation in all areas of schistosomiasis product R&D. As a platform for public-private partnerships (PPPs), the WIPO Re:Search consortium engages the private sector in early-stage R&D for neglected diseases by forging mutually beneficial collaborations and facilitating the sharing of intellectual property (IP) assets between the for-profit and academic/non-profit sectors. The Consortium connects people, resources, and ideas to fill gaps in neglected disease product development pipelines by leveraging the strengths of these two sectors. Using WIPO Re:Search as an example, this article highlights the opportunities for the PPP model to play a key role in the elimination of schistosomiasis.

Role of T lymphocytes and papain enzymatic activity in the protection induced by the cysteine protease against Schistosoma mansoni in mice

•

Papain use deciphered the protection mechanism(s) of the schistosomiasis vaccine.

•

Papain stimulation of innate immunity induced parasite egg attrition.

•

Papain enzymatic and non-enzymatic sites activated T cells and innate immunity.

•

IgG1 antibodies and liver uric acid and ARA levels correlated with protection.

•

Identification of type 2 immunity-inducing cysteine peptidases motifs is required.

Papain, an experimental model protease, was used to decipher the protective mechanism(s) of the cysteine peptidase-based schistosomiasis vaccine. To examine the role of T lymphocytes, athymic nude (nu/nu) and immunocompetent haired (nu/+) mice were subcutaneously (sc) injected with 50 µg active papain two days before percutaneous exposure to 100 cercariae of Schistosoma mansoni. Highly significant (P < 0.005) reductions in worm burden required competent T lymphocytes, while significant increases (P < 0.05) of >80% in dead parasite ova in the small intestine were independent of T cell activity and likely relied on the innate immune axis. To investigate the role of enzymatic activity, immunocompetent mice were sc injected with 50 µg active or E-64-inactivated papain two days before exposure to cercariae. The reductions in worm burden were highly significant (P < 0.0001), reaching >65% and 40% in active and inactivated papain-treated mice, respectively. Similar highly significant (P < 0.0001) decreases of 85% in the viability of parasite ova in the small intestine occurred in both active and inactivated papain-treated mice. These findings indicated that immune responses elicited by one or more papain structural motifs are necessary and sufficient for induction of considerable parasite and egg attrition. Correlates of protection included IgG1-dominated antibody responses and increases in the levels of uric acid and arachidonic acid in the lung and liver upon parasite migration in these sites. Identification of the shared patterns or motifs in cysteine peptidases and evaluation of their immune protective potential will pave the way to the development of a safe, efficacious, storage-stable, and cost-effective schistosomiasis vaccine.

Probiotics and yogurt modulate oxidative stress and fibrosis in livers of Schistosoma mansoni-infected mice

Background

Considerable morbidity, mortality, and economic loss result from schistosomiasis infection. Deposition of Schistosoma eggs in the hepatic portal vein is considered as the main causative agent for the development of liver fibrosis and subsequent liver cirrhosis. Probiotics are exogenous and beneficial microorganisms to living hosts against the harmful effect of many parasites. Strong evidence suggests the importance of probiotics in the control strategy of helminth. The ultimate goal of this study is to evaluate the protective effect of probiotics and yogurt on Schistosoma mansoni-induced oxidative stress and hepatic fibrosis in mice.

Methods

Mice were infected by tail immersion of schistosomal cercariae followed by an oral treatment with either probiotics or yogurt for one week before infection and immediately post-infection. Mice were scarified on day 56 following infection with S. mansoni and liver sample were obtained.

Results

We showed that oral administration of probiotics or yogurt revealed a significant reduction in worm number, egg load, and granuloma size in liver tissue, which is mainly assigned to the decreased expression level of matrix metalloproteinases 9 (MMP-9) in liver tissue. A significant reduction in the oxidative stress markers-induced by S. mansoni infection including lipid peroxidation and nitrite/nitrate was also detected. The level of some antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase) and reduced glutathione was greatly enhanced. Furthermore, treatment with probiotics or yogurt inhibited apoptosis in hepatic tissue, which is mainly assigned to the decreased expression level of caspases-3 in liver tissue.

Conclusion

Our findings represent the promising anti-schistosomal activities of probiotics and yogurt.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2406-3) contains supplementary material, which is available to authorized users.

Schistosomiasis as a cause of acute cholecystitis

Schistosomal cholecystitis is remarkably uncommon disease which is associated with concomitant gallstone disease. The disease prevails with low socio-economic conditions of population. It is still not clear that the widespread fibrocalcific reaction in the wall of gallbladder and the cystic duct, observed for all the reports, predisposes to cholelithiasis or gallstones coexist. In the present study, we report a case of the Saudi male patient affected with schistosomal granulomatous lithiasic cholecystitis. The patient’s gallbladder was badly inflamed therefore performing a safe cholecystectomy in the patient was extremely difficult. Also, infection with schistosoma is related with chronic granulomatous inflammation making the cholecystectomy procedure difficult and risky, therefore, we mainly focused on preventing the injury of bile duct by being prepared that the patient will present a complicated case. This was achieved by using the technique of laparoscopy to safely excise the gall bladder.

Schistosomiasis mansoni in families of fishing workers of endemic area of Alagoas

Abstract Objective: To analyze the epidemiological and clinical aspects involved in the transmission and manifestation of schistosomiasis in a community of fishermen from the endemic area of Alagoas. Methods: Epidemiological, transversal, prospective, descriptive, quantitative study. The coproparasitological survey included 275 family units of fish workers and the epidemiological and clinical ones, those with a positive diagnosis for S. mansoni. Results: The prevalence of schistosomiasis was 13.9% (fishermen), 2.1% (shellfish) and 2.1% (family members). The occurrence of the infection varied according to gender, age, ethnicity and socioeconomic status. Exposure occurred near the home. Autochthonous and predominant low parasite burden, intestinal clinical presentation, abdominal pain and diarrhea were observed. There were no nutritional and pressure changes associated with parasitosis. Adherence to drug therapy and use of the schistosomicidal drug was feared. Conclusion: Fish workers are at high risk for contracting the disease with clinical hepatointestinal manifestation, which requires more intense health actions.

Declining prevalence of hepatitis C virus among university students in one of the main governorates in Egypt

Background and aims

Egypt is considered to have the highest rate of hepatitis C virus (HCV) prevalence worldwide. However, HCV prevalence is currently declining due to the improvement of health education programs, improved environmental sanitation, and the introduction of novel treatment regimens. The aim of this work was to determine the HCV seroprevalence among Menoufia University students.

Methods

The current study included 48,972 students from Menoufia University, Egypt. Blood sample was obtained from every patient for HCV seromarker testing. In anti-HCV-positive subjects, quantitative PCR for HCV RNA was done.

Results

Overall, HCV antibody prevalence rate was 1%. This prevalence was higher in females (304/27,421; 1.1%) than in males (194/21,371; 0.9%). HCV-RNA PCR was positive in 355/48,972 (0.7%); the percentage of HCV PCR positive among the anti-HCV-positive was 71.3% (355/498 patients), with a higher prevalence among females than in males but without statistical significance. In addition, rural areas showed more prevalent HCV seroprevalence than urban areas.

Conclusion

These prevalence rates for HCV infection are lower than that previously reported in the same age group denoting a new evidence for the reduction of prevalence and a hope for successful eradication of HCV in the forthcoming years.

Liver ultrasound elastography for the evaluation of periportal fibrosis in schistosomiasis mansoni: A cross-sectional study

BACKGROUND

ARFI elastrography has been used as a noninvasive method to assess the severity of liver fibrosis in viral hepatitis, although with few studies in schistosomiasis mansoni. We aimed to evaluate the performance of point shear wave elastography (pSWE) for predicting significant periportal fibrosis (PPF) in schistosomotic patients and to determine its best cutoff point.

METHODOLOGY/PRINCIPAL FINDINGS

This cross-sectional study included 358 adult schistosomotic patients subjected to US and pSWE on the right lobe. Two hundred two patients (62.0%) were women, with a median age of 54 (ranging 18-92) years. The pSWE measurements were compared to the US patterns of PPF, as gold standard, according to the Niamey classification. The performance of pSWE was calculated as the area under the ROC curve (AUC). Patients were further classified into two groups: 86 patients with mild PPF and 272 patients with significant PPF. The median pSWE of the significant fibrosis group was higher (1.40 m/s) than that of mild fibrosis group (1.14 m/s, p<0.001). AUC was 0.719 with ≤1.11 m/s as the best cutoff value for excluding significant PPF. Sensitivity and negative predictive values were 80.5% and 40.5%, respectively. Whereas, for confirming significant PPF, the best cutoff value was >1.39 m/s, with specificity of 86.1% and positive predictive value of 92.0%.

CONCLUSIONS/SIGNIFICANCE

pSWE was able to differentiate significant from mild PPF, with better performance to predict significant PPF.

Schistosoma "Eggs-Iting" the Host: Granuloma Formation and Egg Excretion

Schistosomiasis is a major cause of morbidity in humans invoked by chronic infection with parasitic trematodes of the genus Schistosoma. Schistosomes have a complex life-cycle involving infections of an aquatic snail intermediate host and a definitive mammalian host. In humans, adult male and female worms lie within the vasculature. Here, they propagate and eggs are laid. These eggs must then be released from the host to continue the life cycle. Schistosoma mansoni and Schistosoma japonicum reside in the mesenteric circulation of the intestines with egg excreted in the feces. In contrast, S. haematobium are present in the venus plexus of the bladder, expelling eggs in the urine. In an impressive case of exploitation of the host immune system, this process of Schistosome “eggs-iting” the host is immune dependent. In this article, we review the formation of the egg granuloma and explore how S. mansoni eggs laid in vasculature must usurp immunity to induce regulated inflammation, to facilitate extravasation through the intestinal wall and to be expelled in the feces. We highlight the roles of immune cell populations, stromal factors, and egg secretions in the process of egg excretion to provide a comprehensive overview of the current state of knowledge regarding a vastly unexplored mechanism.

Emerging Role of HMGB1 in the Pathogenesis of Schistosomiasis Liver Fibrosis

In chronic schistosomiasis, liver fibrosis is linked to portal hypertension, which is a condition associated with high mortality and morbidity. High mobility group box 1 (HMGB1) was originally described as a nuclear protein that functions as a structural co-factor in transcriptional regulation. However, HMGB1 can also be secreted into the extracellular milieu under appropriate signal stimulation. Extracellular HMGB1 acts as a multifunctional cytokine that contributes to infection, injury, inflammation, and immune responses by binding to specific cell-surface receptors. HMGB1 is involved in fibrotic diseases. From a clinical perspective, HMGB1 inhibition may represent a promising therapeutic approach for treating tissue fibrosis. In this study, we demonstrate elevated levels of HMGB1 in the sera in experimental mice or in patients with schistosomiasis. Using immunohistochemistry, we demonstrated that HMGB1 trafficking in the hepatocytes of mice suffering from acute schistosomiasis was inhibited by Glycyrrhizin, a well-known HMGB1 direct inhibitor, as well as by DIC, a novel and potential anti-HMGB1 compound. HMGB1 inhibition led to significant downregulation of IL-6, IL4, IL-5, IL-13, IL-17A, which are involved in the exacerbation of the immune response and liver fibrogenesis. Importantly, infected mice that were treated with DIC or GZR to inhibit HMGB1 pro-inflammatory activity showed a significant increase in survival and a reduction of over 50% in the area of liver fibrosis. Taken together, our findings indicate that HMGB1 is a key mediator of schistosomotic granuloma formation and liver fibrosis and may represent an outstanding target for the treatment of schistosomiasis.

Non-cirrhotic portal hypertension: an imaging review

Non-cirrhotic portal hypertension (NCPH) comprises a group of diseases that are characterized by increased portal pressure in the absence of cirrhosis of the liver. It may arise as a result of either primary hepatic disease or the effects of systemic disorders on liver. The natural course of NCPH is largely indolent and benign with an overall better outcome than cirrhosis, as long as the complications of portal hypertension are properly managed and regular surveillance is carried out. However, due to the numerous and variable etiological factors and lack of standardized diagnostic criteria, this entity is under-recognized clinically as well as pathologically and often gets mislabeled as cryptogenic cirrhosis. Therefore, it is imperative for radiologists to be aware of the imaging features of various entities that constitute NCPH to facilitate early recognition of this disorder. The present review shall comprehensively discuss the role of imaging in the diagnosis of obliterative portal venopathy, which is a common and one of the most poorly understood disorders leading to NCPH. The other radiologically relevant entities will also be briefly appraised.

Beyond O&P Times Three

Although examination of the stool for ova and parasites times three (O&P ×3) is routinely performed in the United States (US) for the evaluation of persistent and/or chronic diarrhea, the result is almost always negative. This has contributed to the perception that parasitic diseases are nearly non-existent in the country unless there is a history of travel to an endemic area. The increasing number of immigrants from third-world countries, tourists, and students who present with symptoms of parasitic diseases are often misdiagnosed as having irritable bowel syndrome or inflammatory bowel disease. The consequences of such misdiagnosis need no explanation. However, certain parasitic diseases are endemic to the US and other developed nations and affect both immunocompetent and immunocompromised patients. Testing for parasitic diseases either with O&P or with other diagnostic tests, followed by the recommended treatment, is quite rewarding when appropriate. Most parasitic diseases are easily treatable and should not be confused with other chronic gastrointestinal (GI) disorders. In this review, we critically evaluate the symptomatology of luminal parasitic diseases, their differential diagnoses, appropriate diagnostic tests, and management.

Towards elimination of schistosomiasis after 5000 years of endemicity in Egypt

Schistosomiasis is a snail-transmitted infectious disease caused by a long lasting infection with a blood fluke of the genus Schistosoma. S. haematobium and S. mansoni are the species endemic in Egypt. The country has been plagued and seriously suffered from schistosomiasis over the past 5000 years. Great strides had been done in controlling the disease since 1922. The history, epidemiology and the different control approaches were reviewed. Currently, Egypt is preparing towards schistosomiasis elimination by 2020. The new strategy depends on four main axes; large scale treatment in all areas of residual transmission by targeting entire populations with PZQ, intensified snail control, heath education and behavioral changes and expansion of the complementary public health interventions. While on the road towards elimination, we addressed here the important challenges, lessons and the key issues from the different control strategies to help the achievement of our goal. Notably, frangibility of the drug based control, emergence of resistance against PZQ, persistence of some hot spots areas, the need of further control efforts to the high risk individuals and community involvement in the control programs, reconsideration of diagnostic tests used in surveillance, and continous monitoring of the field to detect changes in the snail intermediate host. Importantly, the adaptation between the parasite and its intermediate snail host throughout water bodies in Egypt merits attention as Schistosoma infection can be introduced to the new reclaimed areas. This review may help supplying information for the policy makers to tailor control measures suitable to the local context that could help in the transfer from control to elimination.

Schistosome-Induced Fibrotic Disease: The Role of Hepatic Stellate Cells

Hepatic fibrosis is a common pathology in various liver diseases. Hepatic stellate cells (HSCs) are the main cell type responsible for collagen deposition and fibrosis formation in the liver. Schistosomiasis is characterised by granulomatous fibrosis around parasite eggs trapped within the liver and other host tissues. This response is facilitated by the recruitment of immune cells and the activation of HSCs. The interactions between HSCs and schistosome eggs are complex and diverse, and a better understanding of these interactions could lead to improved resolution of fibrotic liver disease, including that associated with schistosomiasis. Here, we discuss recent advances in HSC biology and the role of HSCs in hepatic schistosomiasis.

Schistosoma mansoni infection suppresses the growth of Plasmodium yoelii parasites in the liver and reduces gametocyte infectivity to mosquitoes

Malaria and schistosomiasis are major parasitic diseases causing morbidity and mortality in the tropics. Epidemiological surveys have revealed coinfection rates of up to 30% among children in Sub-Saharan Africa. To investigate the impact of coinfection of these two parasites on disease epidemiology and pathology, we carried out coinfection studies using Plasmodium yoelii and Schistosoma mansoni in mice. Malaria parasite growth in the liver following sporozoite inoculation is significantly inhibited in mice infected with S. mansoni, so that when low numbers of sporozoites are inoculated, there is a large reduction in the percentage of mice that go on to develop blood stage malaria. Furthermore, gametocyte infectivity is much reduced in mice with S. mansoni infections. These results have profound implications for understanding the interactions between Plasmodium and Schistosoma species, and have implications for the control of malaria in schistosome endemic areas.

Malaria and schistosomiasis are parasitic infectious diseases that cause severe morbidity and mortality in the tropics. Chronic schistosomiasis causes malnutrition and impaired intellectual development to children while malaria can cause fatal acute infections. Since coinfection of these two parasites is common in the tropics, many studies of both epidemiology and coinfection in animal models have been performed in order to reveal interactions between them. Previous animal studies on the interactions between Plasmodium and Schistosoma parasites have focused on the blood stage pathology of the malaria infection, and have consistently shown that parasitaemia can be enhanced in the presence of the helminth. In contrast, we focused on liver immunopathology in mice during coinfection between with Schistosoma and Plasmodium. We show that S. mansoni infection inhibits Plasmodium parasite growth in the liver resulting in a large reduction in the percentage of mice that go on to develop blood stage malaria following inoculation of low numbers of sporozoites. We also demonstrate that gametocyte infectivity is much reduced in mice with S. mansoni infections. Our results imply that S. mansoni infection can reduce malaria transmission both from mosquitoes to mice, and from mice to mosquitoes.

Intestinal Schistosomiasis: A Rare Cause of Abdominal Pain and Weight loss

Abdominal pain is one of the most common reasons for outpatient visits. Although intestinal schistosomiasis is extremely rare in US, it should be considered in the differential diagnosis for those patients with risk factors such as international traveling history. This case report illustrates a unique case of intestinal schistosomiasis, which presented with an eight-week history of nonspecific abdominal pain and weight loss. Her colonoscopy revealed a 10 mm polyp in the colon. Endoscopic mucosal resection confirmed the diagnosis of schistosomiasis. Treatment with Praziquantel resulted in significant improvement of her symptoms.

Direct Biomarkers of Microbial Translocation Correlate with Immune Activation in Adult Zambians with Environmental Enteropathy and Hepatosplenic Schistosomiasis

Microbial translocation is a poorly understood consequence of several disorders such as environmental enteropathy (EE) and hepatosplenic schistosomiasis (HSS). Herein, we compared biomarkers of microbial origin and immune activation in adults with these disorders and in healthy controls. A cross-sectional study was conducted in participants with EE recruited from Misisi compound, Lusaka, Zambia; HSS patients and healthy controls from the University Teaching Hospital, Lusaka. Plasma lipopolysaccharides (LPSs) was measured by limulus amoebocyte lysate assay, plasma 16S ribosomal RNA (16S rRNA) gene copy number was quantified by quantitative real-time polymerase chain reaction, Toll-like receptor ligand (TLRL) activity by QUANTI-Blue detection medium, and cytokines from cell culture supernatant by Cytometric Bead Array. In univariate analysis LPS, 16S rRNA gene copy number, and TLR activity were all high and correlated with each other and with cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-10, and IL-4 secreted by the RAW-Blue cells. After controlling for baseline characteristic, biomarkers of microbial translocation in blood were predictors of TNF-α, IL-6, and IL-10 activation in cell culture supernatant from EE participants and HSS patients but not in healthy controls. TLR activity showed the strongest correlation with TNF-α. These data provide correlative evidence that microbial translocation contributes to systemic cytokine activation in two disorders common in the tropics, with total TLR ligand estimation showing the strongest correlation with TNF-α (r = 0.66, P < 0.001).

Immune modulation of Th1, Th2, and T-reg transcriptional factors differing from cytokine levels in Schistosoma japonicum infection

In spite of long-term integrated control programs for Schistosoma japonicum infection in China, the infection is still persistent due to its zoonotic transmission and disease severity which further complicate its control. Th1, Th2, and T-reg cells are involved in S. japonicum immunity; however, their exact roles in immunopathology of this infection are still questionable. Therefore, the monitoring of these T cell subsets' immune responses during a primary infection of S. japonicum at both transcriptional (mRNA) and protein (cytokines) levels would be essential to point out. In experimentally infected white New Zealand rabbits, mRNA expression levels of TBX2, IRF8, GATA3, STAT6, FoxP3, and MAFF were evaluated using qPCR, whereas Th1 (IFN-γ and TNF-α), Th2 (IL4 and IL13), and T-reg (IL10 and TGF-β1) cytokines were measured by ELISA test. Those parameters were estimated at two phases: the first being 4 and 8 weeks post-infection and the second phase at 12 weeks post-infection. The infected rabbits were categorized into group1 which was treated with praziquantel after the 8th week of infection and group 2 which was left untreated. In the first stage of infection, Th1 was superior to the other types at both mRNA (TBX2 and IRF8) and protein (IFN-γ and TNF-α) levels, but at the late stage, Th2 cytokines (IL4 and IL13) were surprisingly dominated without comparable change in Th2 transcriptional level in group 1. Concisely, the evaluation of T cell transcriptional factors provided clearer evidence about T cellular roles which would be a valuable supplement to control this disease in terms of protective and therapeutic vaccinations.

Protection against Schistosoma haematobium infection in hamsters by immunization with Schistosoma mansoni gut-derived cysteine peptidases, SmCB1 and SmCL3

We examined the immunogenicity and protective potential of SmCB1 and SmCL3 cysteine peptidases, alone and in combination, in hamsters challenged with S. haematobium. For each of two independent experiments, eight Syrian hamsters were immunized twice with a three week-interval with 0 (controls), 20 µg SmCB1, 20 µg SmCL3, or 10 µg SmCB1 plus 10 µg SmCL3, and then percutaneously exposed eight weeks later to 100 S. haematobium cercariae. Hamsters from each group were assessed for humoral and whole blood culture cytokine responses on day 10 post challenge infection, and examined for parasitological parameters 12 weeks post infection. At day 10 post-infection we found that SmCB1 and SmCL3 elicited low antibody titres and weak but polarized cytokine type 2 responses. Nevertheless, both cysteine peptidases, alone or in combination, evoked reproducible and highly significant reduction in challenge worm burden (>70%, P < 0.02) as well as a significant reduction in worm egg counts and viability. The data support our previous findings and show that S. mansoni cysteine peptidases SmCB1 and SmCL3 are efficacious adjuvant-free vaccines that induce protection in mice and hamsters against both S. mansoni and S. haematobium.

Surgical and immune reconstitution murine models in bone marrow research: Potential for exploring mechanisms in sepsis, trauma and allergy

Bone marrow, the vital organ which maintains lifelong hemopoiesis, currently receives considerable attention, as a source of multiple cell types which may play important roles in repair at distant sites. This emerging function, distinct from, but closely related to, bone marrow roles in innate immunity and inflammation, has been characterized through a number of strategies. However, the use of surgical models in this endeavour has hitherto been limited. Surgical strategies allow the experimenter to predetermine the site, timing, severity and invasiveness of injury; to add or remove aggravating factors (such as infection and defects in immunity) in controlled ways; and to manipulate the context of repair, including reconstitution with selected immune cell subpopulations. This endows surgical models overall with great potential for exploring bone marrow responses to injury, inflammation and infection, and its roles in repair and regeneration. We review three different murine surgical models, which variously combine trauma with infection, antigenic stimulation, or immune reconstitution, thereby illuminating different aspects of the bone marrow response to systemic injury in sepsis, trauma and allergy. They are: (1) cecal ligation and puncture, a versatile model of polymicrobial sepsis; (2) egg white implant, an intriguing model of eosinophilia induced by a combination of trauma and sensitization to insoluble allergen; and (3) ectopic lung tissue transplantation, which allows us to dissect afferent and efferent mechanisms leading to accumulation of hemopoietic cells in the lungs. These models highlight the gain in analytical power provided by the association of surgical and immunological strategies.

Granulomas in the gastrointestinal tract: deciphering the Pandora's box

Granulomas are organised collection of activated histiocytes induced by a persistent antigen stimulus. A wide variety of antigens encountered by the gastrointestinal tract are of this nature and hence the resulting granulomatous inflammation represents a tissue reaction pattern. The potential causes can be broadly classified as infections or non-infectious immune reactions. There is also a group where a cause is never identified. Granulomas may be of varying morphological appearance, most commonly epithelioid, foreign body type, suppurative and necrotizing. This may provide a clue as to the aetiology; however, in most cases, the cause requires further inquiry. Pathologists may need to cut deeper levels to look for foreign material and apply special stains to look for microorganisms. Pathologists also need to be certain that the process is a true granuloma and not a mimic. The site of occurrence in the gastrointestinal tract and the clinical setting is often paramount in establishing the aetiology. For instance, infections are more likely the cause in developing countries or when there is immunosuppression. Similarly, granulomas in the stomach are usually due to Crohn's disease; however, it is only rarely the cause of granulomas isolated to the appendix.