Schistosomiasis, hepatitis B and hepatitis C co-infection

Is Schistosoma mansoni playing a part in liver carcinogenesis?

The relationship between Schistosoma mansoni (Sm) and hepatocellular carcinoma (HCC) has been evaluated by many studies that point towards a co-relation between schistosomal infection and HCC. While many such studies demonstrated that Sm infection in the presence of another carcinogenic factors leads to HCC, none of these studies could conclusively prove the cancer-inducing ability of Sm in humans, independent of other carcinogenic factors. The aim of this work is to present the current understanding on the association of Sm with HCC. Many epidemiological, pathological, and clinical studies have shown the role of multiple events like chronic inflammation and fibrosis as well as hepato-toxic agents like soluble egg antigens (SEAs), which help in creating a micro-environment which is suitable for HCC development. The role of Sm infection and deposited eggs in causing persistent inflammation, advanced fibrosis, and the role of SEAs, especially IPSE/alpha-1, is emphasised. This work concludes that Sm infection has the potential to induce cancer independently but the same has not been reported in humans to date. Extensive research is required to establish a causal relationship between Sm infection and HCC induction, or a complete lack thereof. However, Sm infection definitely acts along with other carcinogenic factors to induce HCC at a much faster pace and also leads to an aggressive form of liver cancer, which the other carcinogenic factor could not have achieved alone.

Morbidity burden of imported chronic schistosomiasis among West African migrants

BACKGROUND

Past exposure to schistosomiasis is frequent among migrants from endemic countries, and chronic untreated infection may lead to long-term morbidities.

METHODS

We carried out a prospective population-based cross-sectional study among migrants from endemic Sub-Saharan countries living in Barcelona, Spain. Participants had not been previously diagnosed or treated for schistosomiasis. Clinical signs and symptoms were scrutinised through a systematic revision of electronic medical records and an on-site standardised questionnaire, and blood and urine samples were screened for Schistosoma.

FINDINGS

We recruited 522 eligible participants, 74.3% males, mean age 42.7 years (SD=11.5, range 18-76), Overall, 46.4% were from Senegal and 23.6% from Gambia. They had lived in the European Union for a median of 16 years (IQR 10-21). The prevalence of a Schistosoma-positive serology was 35.8%. S. haematobium eggs were observed in urine samples in 6 (1.2%) participants. The most prevalent symptoms among Schistosoma-positive participants were chronic abdominal pain (68.8%, OR=1.79; 95%CI 1.2-2.6), eosinophilia (44.9%, OR=2.69; 95%CI 1.8-4.0) and specific symptoms associated with urinary schistosomiasis, like self-reported episodes of haematuria (37.2%; OR=2.47; 95%CI 1.6-3.8), dysuria (47.9%, OR=1.84; 95%CI=1.3-2.7) and current renal insufficiency (13.4%; OR=2.35; 95%CI=1.3-4.3). We found a significant prevalence of gender-specific genital signs and symptoms among females (mainly menstrual disorders) and males (erectile dysfunction and pelvic pain). Individuals typically presented with a multitude of interconnected symptoms, most commonly chronic abdominal pain, which are often disregarded.

CONCLUSIONS

Despite the lack of urine parasite identification, the high incidence of clinical signs and symptoms strongly correlated with a positive schistosomiasis serology suggests the existence of a heavy clinical burden among long-term West African migrants living for years/decades in the study region. More research is urgently required to determine whether these symptoms are the result of long-term sequelae or a persistent active Schistosoma infection.

Beyond schistosomiasis: unraveling co-infections and altered immunity

Schistosomiasis is a neglected tropical disease caused by the helminth Schistosoma spp. and has the second highest global impact of all parasites. Schistosoma are transmitted through contact with contaminated fresh water predominantly in Africa, Asia, the Middle East, and South America. Due to the widespread prevalence of Schistosoma, co-infection with other infectious agents is common but often poorly described. Herein, we review recent literature describing the impact of Schistosoma co-infection between species and Schistosoma co-infection with blood-borne protozoa, soil-transmitted helminths, various intestinal protozoa, Mycobacterium, Salmonella, various urinary tract infection-causing agents, and viral pathogens. In each case, disease severity and, of particular interest, the immune landscape, are altered as a consequence of co-infection. Understanding the impact of schistosomiasis co-infections will be important when considering treatment strategies and vaccine development moving forward.

Cloning, characterization, and inhibition of the novel β-carbonic anhydrase from parasitic blood fluke, Schistosoma mansoni

Schistosoma mansoni is an intestinal parasite with one β-class carbonic anhydrase, SmaBCA. We report the sequence enhancing, production, catalytic activity, and inhibition results of the recombinant SmaBCA. It showed significant catalytic activity on CO₂ hydration in vitro with k_cat 1.38 × 10⁵ s^-1 and k_cat/K_m 2.33 × 10⁷ M^-1 s^-1. Several sulphonamide inhibitors, from which many are clinically used, showed submicromolar or nanomolar inhibitory effects on SmaBCA. The most efficient inhibitor with a K_I of 43.8 nM was 4-(2-amino-pyrimidine-4-yl)-benzenesulfonamide. Other effective inhibitors with K_Is in the range of 79.4-95.9 nM were benzolamide, brinzolamide, topiramate, dorzolamide, saccharin, epacadostat, celecoxib, and famotidine. The other tested compounds showed at least micromolar range inhibition against SmaBCA. Our results introduce SmaBCA as a novel target for drug development against schistosomiasis, a highly prevalent parasitic disease.

Global burden of Liver Disease: 2023 Update

Liver disease accounts for 2 million deaths and is responsible for 4% of all deaths (1 out of every 25 deaths worldwide); approximately 2/3 of all liver related deaths occur in men. Deaths are largely attributable to complications of cirrhosis and hepatocellular carcinoma, with acute hepatitis accounting for a smaller proportion of deaths. The most common causes of cirrhosis worldwide are related to viral hepatitis, alcohol, and nonalcoholic fatty liver disease (NAFLD). Hepatotropic viruses are the etiological factor in most cases of acute hepatitis, but drug-induced liver injury increasingly accounts for a significant proportion of cases. This iteration of the global burden of liver disease is an update of the 2019 version and focuses mainly on areas where significant new information is available like alcohol-associated liver disease, NAFLD, viral hepatitis, and HCC. We also devote a separate section to the burden of liver disease in Africa, an area of the world typically neglected in such documents.

Noninvasive diagnosis of periportal fibrosis in schistosomiasis mansoni: A comprehensive review

Schistosomiasis mansoni is a neglected disease and key public health problem, mainly due to its high prevalence, the scarcity of public policies, and the severity of some clinical forms. Periportal fibrosis (PPF) is the commonest complication of chronic schistosomiasis mansoni and its diagnosis requires different techniques. Even though wedge biopsy of the liver is considered the gold standard, it is not justified in non-surgical patients, and percutaneous liver biopsy may be informative but does not have sufficient sensitivity. Noninvasive PPF tests mostly include biological (serum biomarkers or combined scores) or physical assessments (imaging assessment of fibrosis pattern or tissue stiffness). Moreover, imaging techniques, such as ultrasound, computed tomography, magnetic resonance imaging, and elastography are applied not only to support the diagnosis of schistosomiasis, but also to assess and detect signs of portal hypertension and organ damage due to chronic schistosomiasis. A combination between a comprehensive history and physical examination with biomarkers for liver fibrosis and imaging methods seems to offer the best approach for evaluating these patients. In addition, understanding their strengths and limitations will allow a more accurate interpretation in the clinical context and can lead to greater accuracy in estimating the degree of fibrosis in patients with Schistosomiasis mansoni (S. mansoni) infection. This review will discuss the different noninvasive methods that are currently available for the evaluation of PPF in S. mansoni infection, and their application, advantages, and limitations in clinical practice.

Risk Factors for Pancreatic Cancer: Emerging Role of Viral Hepatitis

Pancreatic cancer is one of the most aggressive malignant neoplastic diseases. The incidence and mortality rates of this disease vary depending on geographical area, which might be explained by the different exposure to risk factors. To improve the prognosis of patients with pancreatic cancer, different approaches are needed for an earlier diagnosis. Identification of risk factors and implementation of screening strategies are essential for a better prognosis. Currently, the risk factors for pancreatic cancer fall into two broad categories, namely extrinsic and intrinsic factors. Extrinsic factors include alcohol consumption, smoking, a diet rich in saturated fats, and viral infections such as chronic infection with hepatitis B and C viruses. The pathophysiological mechanisms explaining how these hepatotropic viruses contribute to the development of pancreatic cancer are not fully elucidated. The common origin of hepatocytes and pancreatic cells in the multipotent endodermal cells, the common origin of the blood vessels and biliary ducts of the pancreas and the liver, or chronic inflammatory changes may be involved in this interaction. A careful monitoring of patients with viral liver infections may contribute to the early diagnosis of pancreatic cancer and improve the prognosis of these patients.

Co-infections of Schistosoma spp. and Malaria with Hepatitis Viruses from Endemic Countries: A Systematic Review and Meta-Analysis

BACKGROUND

Co-infection of schistosomiasis and malaria with hepatitis B virus (HBV) and hepatitis C virus (HCV) are common in countries where schistosomiasis and malaria are endemic.

OBJECTIVE

The present systematic review and meta-analysis was conducted to assess the prevalence of malaria/hepatitis viruses and Schistosoma/hepatitis viruses' co-infections.

MATERIALS AND METHODS

Relevant published studies on the co-infection of malaria and Schistosoma spp. with HBV and HCV were retrieved via international databases (PubMed, Scopus, Web of Science, and Google Scholar). Regarding meta-analysis, the random-effect model was employed by forest plot with a 95% of confidence interval (CI).

RESULTS

A total of 22 studies, including 15 studies with malaria/hepatitis viruses' co-infection and 7 studies with Schistosoma/hepatitis viruses' co-infection met the eligibility criteria. The co-infection of malaria/HCV and malaria/HBV in different populations were 15% (95% CI, 0-77%) and 5% (95% CI, 1-10%), respectively. Moreover, Schistosoma/HCV and Schistosoma/HBV co infection were detected in 7% (95% CI, 0-54%) and 2% (95% CI, 0-7%), respectively.

CONCLUSION

The overlaps between Schistosoma spp. and malaria with hepatitis B and C viruses in endemic countries with lower income levels were high, which deserve further attention.

Noninvasive Assessment of Schistosoma-Related Periportal Fibrosis

Schistosomiasis affects nearly 250 million individuals in the world. Hepatosplenic schistosomiasis (HSS) results in periportal fibrosis (PPF) and portal hypertension (pHTN). Ultrasound has been extensively used for the diagnosis of Schistosoma-related PPF and a number of staging methods have been validated for this purpose such as Strickland classification and Niamey protocol. Nevertheless, the application of noninvasive techniques, particularly elastography modalities, has not been well explored. In this review, we describe the various noninvasive diagnostic tools for assessment of Schistosoma-related PPF including US parameters, serum biomarkers, and US-based elastography techniques. While elastography techniques have demonstrated value in the evaluation of HSS, the evidence remains limited with most studies recruiting a small number of patients. Longitudinal studies with larger sample size are required in order to devise robust criteria to accurately assess the performance of noninvasive techniques in the prediction of both regression and progression of the degree of PPF and identify their cost-effectiveness in community screening.

Schistosoma mansoni infection and the occurrence, characteristics, and survival of patients with hepatocellular carcinoma: an observational study over a decade

Schistosoma mansoni infection (SMI) is suspected to be directly and indirectly involved in hepato-carcinogenesis. This study evaluated the association of a previous SMI with hepatocellular carcinoma (HCC) development, patients, tumor characteristics, treatment outcomes, and survival. This observational study included patients with HCC with and without previous SMI who presented to the multidisciplinary HCC clinic, Kasr-Alainy hospital (November 2009 to December 2019). It also included 313 patients with liver cirrhosis without HCC. Clinical and laboratory features of the patients (complete blood count, liver/renal functions , alpha-fetoprotein, and hepatitis B/C status), tumor characteristics (Triphasic CT and/or dynamic MRI), liver stiffness (transient elastography), HCC treatment outcome, and overall survival were studied. This study included 1446 patients with HCC; 688(47.6%) composed group-1, defined by patients having a history of SMI, and 758(52.4%) were in group-2 and without history of SMI. Male sex, smoking, diabetes mellitus, splenomegaly, deteriorated performance status, synthetic liver functions, and platelet count were significantly higher in group-1. The groups did not differ with regard to liver stiffness, tumor characteristics, or the occurrence of post-HCC treatment hepatic decompensation or recurrence. HCC treatment response was better in group-2. Group-1 showed lower sustained virological response to hepatitis C direct-acting antivirals (DAAs) compared with group-2 (60% versus 84.3%, respectively, P = 0.027). Prior SMI was associated with HCC (adjusted odds ratio = 1.589, 95% confidence interval = 1.187-2.127), and it was concluded that it increases the risk of HCC. In addition, it significantly affects the performance status, laboratory characteristics, response to DAAs, and overall survival.

Does Schistosoma Mansoni Facilitate Carcinogenesis?

Schistosomiasis is one of the most prominent parasite-induced infectious diseases, causing tremendous medical and socioeconomic problems. Current studies have reported on the spread of endemic regions and the fear of development of resistance against praziquantel, the only effective drug available. Among the Schistosoma species, only S. haematobium is classified as a Group 1 carcinogen (definitely cancerogenic to humans), causing squamous cell carcinoma of the bladder, whereas infection with S. mansoni is included in Group 3 of carcinogenic hazards to humans by the International Agency for Research on Cancer (IARC), indicating insufficient evidence to determine its carcinogenicity. Nevertheless, although S. mansoni has not been discussed as an organic carcinogen, the multiplicity of case reports, together with recent data from animal models and cell culture experiments, suggests that this parasite can predispose patients to or promote hepatic and colorectal cancer. In this review, we discuss the current data, with a focus on new developments regarding the association of S. mansoni infection with human cancer and the recently discovered biomolecular mechanisms by which S. mansoni may predispose patients to cancer development and carcinogenesis.

Hepatosplenic schistosomiasis, the ignored morbidity: experience from a referral hospital in Ethiopia

BACKGROUND

Hepatosplenic schistosomiasis (HSS) is an important chronic complication of Schistosoma infection. However, its diagnosis and management are complicated due to lack of evidence and uniform guidance. In this study, we described the clinical profile and management of HSS in one of Ethiopia's referral hospitals.

METHODS

A hospital-based, cross-sectional study was conducted using the medical records of patients diagnosed with HSS based on clinical symptoms and typical ultrasound findings observed at the gastroenterology clinic of Dessie referral hospital from September 2018 to December 2019.

RESULTS

A total of 55 patient files were evaluated. Most patients (n=39; 70%) presented with upper gastrointestinal bleeding and severe anaemia. Nearly three-quarters of patients were admitted and 31 (56%) received a blood transfusion. Hepatitis B coinfection was documented in 11 patients (20%). Upper gastrointestinal endoscopy was performed in 31 patients (56%), in whom large oesophageal varices with red signs were the most common finding. Among patients who had endoscopy, band ligation was carried out in 21 cases (68%). Praziquantel was administered to 11 patients (20%).

CONCLUSION

HSS causes severe complications of portal hypertension, like variceal bleeding, which are currently not adequately treated. In addition to already existing preventive efforts, we advise control programmes to also address acute management and rehabilitation of these patients.

Prevalence and co-infection of schistosomiasis/hepatitis B among rural populations in endemic areas in Hubei, China

Background

Both hepatitis B virus (HBV) infection and schistosomiasis are important public health problems in China. Concurrent infection between HBV and schistosomiasis is often observed in areas where schistosomiasis is endemic. The aim of this study was to determine the prevalence of schistosomiasis and HBV in schistosomiasis-affected areas, to explore whether schistosomiasis patients are more susceptible to HBV and to determine if the prevalence of HBV in high-endemic areas of schistosomiasis is higher than in low-endemic areas.

Methods

A total of 6526 participants from 13 villages in Hubei province were included in a cross-sectional study and blood samples were collected and examined. Qualitative variables were compared between groups using Pearson’s chi-squared test or Fisher’s exact test as appropriate.

Results

Of the 6526 participants, the overall prevalence was 8.27% for schistosomiasis and 2.67% for HBV. The prevalence of hepatitis B among participants who were Schistosoma antibody positive (25.37%) was higher than the prevalence in participants who were Schistosoma antibody negative (0.62%; χ²=1169.358, p<0.001, odds ratio 54.659). We also observed that there was no difference in the prevalence of hepatitis B between males and females in areas where schistosomiasis was endemic (χ²=1.827, p=0.177), but the prevalence of hepatitis B in middle-aged people was higher than in other age groups (χ²=47.877, p<0.001).

Conclusions

There was an association between schistosomiasis and HBV infection. However, more work is needed to find the causal relationship between schistosomiasis and HBV infection.

Effects of schistosomes on host anti-viral immune response and the acquisition, virulence, and prevention of viral infections: A systematic review

Although a growing number of studies suggest interactions between Schistosoma parasites and viral infections, the effects of schistosome infections on the host response to viruses have not been evaluated comprehensively. In this systematic review, we investigated how schistosomes impact incidence, virulence, and prevention of viral infections in humans and animals. We also evaluated immune effects of schistosomes in those coinfected with viruses. We screened 4,730 studies and included 103. Schistosomes may increase susceptibility to some viruses, including HIV and Kaposi’s sarcoma-associated herpesvirus, and virulence of hepatitis B and C viruses. In contrast, schistosome infection may be protective in chronic HIV, Human T-cell Lymphotropic Virus-Type 1, and respiratory viruses, though further research is needed. Schistosome infections were consistently reported to impair immune responses to hepatitis B and possibly measles vaccines. Understanding the interplay between schistosomes and viruses has ramifications for anti-viral vaccination strategies and global control of viral infections.

Many studies have described the effects of parasitic Schistosoma worm infections on the way that humans and animals respond to a variety of viral infections. Our goal was to evaluate, in a systematic manner, how having a schistosome parasitic infection affects a host’s susceptibility to viral infections, the clinical disease course of viral infections, and prevention of viral infections by vaccines. We also assessed the effects of schistosome infection on the host immune response to viruses. We screened 4,730 studies for potential relevance and included 103 of them in this review. Overall, our analysis showed that schistosome infection impairs the host response to many viruses. This includes increasing host susceptibility to HIV and possibly Kaposi’s sarcoma-associated herpesvirus, worsening the severity of clinical disease in hepatitis B and C infections, and decreasing immune responses to vaccines for hepatitis B and possibly measles. The studies that we analyzed also suggested that schistosome infection may protect the host against poor clinical outcomes from some viral infections including Human T-cell Lymphotropic Virus-Type 1, respiratory viruses, and chronic HIV. We discuss how these findings might be interpreted, and the additional research needed, in order to improve anti-viral vaccination strategies and control of viral infections globally.

Two rivals or colleagues in the liver? Hepatit B virus and Schistosoma mansoni co-infections: A systematic review and meta-analysis

BACKGROUND

Globally, hepatitis B and schistosomiasis (Mansoni) together affect about 300 million people; which cause hepatic disorders worldwide. Given that little is known about co-infections with hepatitis B and schistosoma mansoni, the present study investigates these two health problems alone and together and their possible correlation.

METHODS

A search was conducted for reports published between January 1990 and October 2020 by using Embase, Scopus, PubMed, Web of Science databases; Out of a total of 20 studies, 14 cross-sectional studies (6329 people) and 6 case-control studies (2138 individual) were reviewed. The pooled prevalence of hepatitis B virus (HBV), S.mansoni infections, and their co-infections; heterogeneity and the Odds Ratio (OR) were evaluated by Stata 11.2.

FINDINGS

Among the included studies in the inclusion criteria, the pooled prevalence of hepatitis B, S. mansoni was 34% (95% CI, 0.23-0.46), 41% (95% CI, 0.24-0.59) and their co-infections was 18% (95% CI, 0.11-0.25) by regions. The hepatitis B and S. mansoni correlation was significant in populations with schistosoma compared to control group (OR, 2.12; 95% CI, 1.36-3.30).

COMMENTARY

Our results showed that in addition to the high global prevalence of hepatitis B- S. mansoni (co) infections in the included studies, there is a significant association between them, especially in people suffering from schistosoma. These results highlight the importance of integrated interventions measurements against coexistence of parasitic and viral diseases. We know that more research studies need to be done in this field and global monitoring should be considered for the co-infection of these two important complications.

Dynamic, Helminth-Induced Immune Modulation Influences the Outcome of Acute and Chronic Hepatitis B Virus Infection

BACKGROUND

Chronic hepatitis B develops more frequently in countries with high prevalence of helminth infections. The crosstalk between these 2 major liver-residing pathogens, Schistosoma mansoni and hepatitis B virus (HBV), is barely understood.

METHODS

We used state-of-the-art models for both acute and chronic HBV infection to study the pathogen-crosstalk during the different immune phases of schistosome infection.

RESULTS

Although liver pathology caused by schistosome infection was not affected by either acute or chronic HBV infection, S mansoni infection influenced HBV infection outcomes in a phase-dependent manner. Interferon (IFN)-γ secreting, HBV- and schistosome-specific CD8 T cells acted in synergy to reduce HBV-induced pathology during the TH1 phase and chronic phase of schistosomiasis. Consequently, HBV was completely rescued in IFN-γ-deficient or in TH2 phase coinfected mice demonstrating the key role of this cytokine. It is interesting to note that secondary helminth infection on the basis of persistent (chronic) HBV infection increased HBV-specific T-cell frequency and resulted in suppression of virus replication but failed to fully restore T-cell function and eliminate HBV.

CONCLUSIONS

Thus, schistosome-induced IFN-γ had a prominent antiviral effect that outcompeted immunosuppressive effects of TH2 cytokines, whereas HBV coinfection did not alter schistosome pathogenicity.

Schistosomiasis in Nigeria: Gleaning from the past to improve current efforts towards control

The effort to control schistosomiasis in Nigeria has been scaled up the past few years. Schistosomiasis affects all age groups, however, school children are at the highest risk of the disease. In the past years, global partners in schistosomiasis control have renewed their commitments. Many countries including few in Africa are working towards eliminating the disease. In Nigeria, the transmission of schistosomiasis is still active. This poses a serious health challenge as morbidity builds up in infected individuals. Mass drug administration (MDA) has helped to reduce morbidity but it is not adequate to abate transmission in many areas of the country. The integration of other aspects of control will provide a more sustainable result. This review attempted to discuss schistosomiasis transmission patterns in Nigeria in different eras. We identified some pitfalls in efforts towards the control of schistosomiasis in Nigeria. We recommended research priority in areas of neglect and advocated for integrated control.

Assessment of schistosomiasis endemicity and preventive treatment on coronavirus disease 2019 outcomes in Africa

Since the coronavirus disease 2019 (COVID-19) pandemic, attention has been drawn to the possible interactions between the deadly disease and a few other infections. Although schistosomiasis and other neglected tropical diseases have been proposed to influence susceptibility to COVID-19, no study has looked into this. This study therefore investigated the impact of schistosomiasis on the transmission of COVID-19 and also evaluated the role of praziquantel treatment coverage on COVID-19 outcomes in African countries. The schistosomiasis endemicity and the preventive chemotherapy coverage index statuses were obtained from the World Health Organization databank. COVID-19 data were obtained from the Worldometer COVID-19 report. The data were adjusted and the percentage of COVID-19 cases confirmed, and active cases, recovery and deaths were computed. The COVID-19 outcomes were evaluated relative to schistosomiasis endemicity and treatment coverage. COVID-19 outcomes, especially active cases and recovery rates, were significantly improved in schistosomiasis nonendemic African countries (p < 0.05). While COVID-19 confirmed cases were significantly higher in countries with >75% schistosomiasis preventive chemotherapy coverage index (p < 0.05), improved COVID-19 outcomes were observed relative to active cases and recovery in countries with >75% preventive chemotherapy coverage index (p > 0.05). Schistosomiasis endemicity may be associated with negative COVID-19 outcomes, and higher praziquantel treatment coverage could reduce COVID-19 active cases and improve the recovery rate.

Inhibition of HIV-1 Protease by Carpobrotus edulis (L.)

Carpobrotus edulis (L.) is a plant commonly found in the Eastern Cape Province of South Africa and is used for the general treatment of infections relating to the human immunodeficiency virus (HIV). HIV-1 protease plays an important role during HIV replication and maturation to its infectious form, and therefore inhibition of the enzyme is one of the main focus areas in drug development. The inhibitory effect of a water extract of C. edulis leaves against HIV-1 protease activity was determined using the SensoLyte® 520 HIV-1 protease assay fluorimetric kit and employing a HiLyte Fluor™488/QXL™520 fluorescence resonance energy transfer (FRET) peptide. Cytotoxicity of the extract towards HeLa Chang cell lines was determined using an in vitro MTT assay, and the phytochemical profile of the extract was determined with FT-IR and LC-MS. HIV-1 protease activity was inhibited 83.06% (IC₅₀ 1.6 mg/ml) (p < 0.0001) by the pepstatin A inhibitor control. Treatment with all C. edulis extract concentrations (16, 1.6, 0.16, and 0.016 mg/ml) inhibited HIV-1 protease activity significantly (p < 0.0001) in a typical dose response manner. With regards to cytotoxicity, the negative controls containing untreated HeLa Chang cells exhibited high formazan formation rates in contrast with the positive controls, containing curcumin, which reduced formazan formation significantly (p < 0.001), exhibiting cytotoxicity towards the cells. There was no significant (p > 0.05) difference in the formazan formation rates between the negative controls and 1, 0.5, 0.125, 0.065, 0.031, and 0.015 mg/ml plant extract, confirming no toxicity of C. edulis extracts towards HeLa Chang cells. Major functional phytochemical compounds identified included alcohols, phenols, alkanes, amines, carboxylic acids, and esters. LC-ESI-TOF/MS analysis revealed the putative identities of main compounds present in the aqueous leaves extract, including some that contribute to its anti-HIV-1 protease action.

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.

Hepatitis B - chronic carrier status and pregnancy outcomes: An obstetric perspective

Antenatal screening for hepatitis B surface antigen (HBsAg) only identifies women with hepatitis B virus (HBV) infection for neonatal immunoprophylaxis. It does not reflect the phase of chronic infection, viral genotype and activity, hepatic inflammation, or other co-existing liver disorders. Coinfection with other viruses and micro-organisms may also be present. These factors in various combinations can impact pregnancy outcomes, and they are probably responsible for the conflicting literature on this issue. Pregnancy complications may interact with maternal HBV infection and hepatitis flares, leading to serious and lethal complications. Hepatitis flares are common especially postpartum, and they are unpredictable and unpreventable with antiviral treatment. Evidence on the association between HBsAg seropositivity with gestational diabetes mellitus, preterm birth, increased foetal growth, and reduced pregnancy hypertensive disorders is stronger than other adverse pregnancy outcomes. Baseline assessment of liver function, and viral markers and activity, can delineate the truly high-risk pregnancies for close monitoring.

Elevation of C-reactive protein, P-selectin and Resistin as potential inflammatory biomarkers of urogenital Schistosomiasis exposure in preschool children

Background

Schistosomiasis is known to induce inflammatory immune responses. C-reactive protein (CRP), resistin and P-selectin are serological inflammatory markers that rise during the acute stages of infection. Here, we propose such inflammatory biomarkers have a potential for use in urogenital schistosomiasis diagnostic screening for exposure and infection in preschool-aged children.

Methods

As part of a larger study on urogenital schistosomiasis, 299 preschool children aged 1–5 years were included in this cross-sectional study. Parasitological diagnosis was conducted using urine filtration for Schistosoma haemtobium infection, and Kato Katz for S. mansoni infection. Serum levels of P-selectin, resistin, CRP, and antibodies against S. haematobium cercarial antigen preparation (CAP) and soluble worm antigen preparation (SWAP) were measured by ELISA.

Results

Of the 299 participants, 14% were egg positive for S. haematobium. Serology showed 46 and 9% of the participants to have been exposed to S. haematobium cercarial antigens and adult worm antigens, respectively. Levels of P-selectin were significantly higher in participants infected with S. haematobium (egg-positive) than in uninfected participants (p = 0.001). Levels of P-selectin were also higher in those exposed to cercarial antigen than in unexposed participants (p = 0.019). There was a positive correlation between P-selectin and infection intensity (r = 0.172; p = 0.002), as well as with IgM responses to CAP and SWAP (r = 0.183; p = 0.001); (r = 0.333; p < 0.0001) respectively. CRP significantly correlated with IgM responses to CAP (r = 0.133; p = 0.029) while resistin correlated with IgM responses to CAP and SWAP (r = 0.127; p = 0.016); (r = 0.197; p = 0.0004). CRP levels were higher in those exposed to cercarial and adult worm antigens than unexposed participants (p = 0.035); (p = 0.002) respectively, while resistin was higher in participants exposed to cercarial antigen than unexposed participants (p = 0.024).

Conclusion

In this preschool population, P-selectin is significantly associated with urogenital schistosome infection and intensity; hence a potential biomarker for infection diagnosis and disease monitoring. The inflammatory biomarkers (P-selectin, Resistin and CRP) were significantly higher in participants exposed to cercarial antigens than unexposed individuals indicating an underlying inflammatory environment.

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.

Human NK Cells Lyse Th2-Polarizing Dendritic Cells via NKp30 and DNAM-1

Cross-talk between NK cells and dendritic cells (DCs) is important in Th1 immune responses, including antitumor immunity and responses to infections. DCs also play a crucial role in polarizing Th2 immunity, but the impact of NK cell-DC interactions in this context remains unknown. In this study, we stimulated human monocyte-derived DCs in vitro with different pathogen-associated molecules: LPS or polyinosinic-polycytidylic acid, which polarize a Th1 response, or soluble egg Ag from the helminth worm Schistosoma mansoni, a potent Th2-inducing Ag. Th2-polarizing DCs were functionally distinguishable from Th1-polarizing DCs, and both showed distinct morphology and dynamics from immature DCs. We then assessed the outcome of autologous NK cells interacting with these differently stimulated DCs. Confocal microscopy showed polarization of the NK cell microtubule organizing center and accumulation of LFA-1 at contacts between NK cells and immature or Th2-polarizing DCs but not Th1-polarizing DCs, indicative of the assembly of an activating immune synapse. Autologous NK cells lysed immature DCs but not DCs treated with LPS or polyinosinic-polycytidylic acid as reported previously. In this study, we demonstrated that NK cells also degranulated in the presence of Th2-polarizing DCs. Moreover, time-lapse live-cell microscopy showed that DCs that had internalized fluorescently labeled soluble egg Ag were efficiently lysed. Ab blockade of NK cell-activating receptors NKp30 or DNAM-1 abrogated NK cell lysis of Th2-polarizing DCs. Thus, these data indicate a previously unrecognized role of NK cell cytotoxicity and NK cell-activating receptors NKp30 and DNAM-1 in restricting the pool of DCs involved in Th2 immune responses.

Surgical portosystemic shunts versus devascularisation procedures for prevention of variceal rebleeding in people with hepatosplenic schistosomiasis

BACKGROUND

Hepatosplenic schistosomiasis is an important cause of variceal bleeding in low-income countries. Randomised clinical trials have evaluated the outcomes of two categories of surgical interventions, shunts and devascularisation procedures, for the prevention of variceal rebleeding in people with hepatosplenic schistosomiasis. The comparative overall benefits and harms of these two interventions are unclear.

OBJECTIVES

To assess the benefits and harms of surgical portosystemic shunts versus oesophagogastric devascularisation procedures for the prevention of variceal rebleeding in people with hepatosplenic schistosomiasis.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, LILACS, reference lists of articles, and proceedings of relevant associations for trials that met the inclusion criteria (date of search 11 January 2018).

SELECTION CRITERIA

Randomised clinical trials comparing surgical portosystemic shunts versus oesophagogastric devascularisation procedures for the prevention of variceal rebleeding in people with hepatosplenic schistosomiasis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the trials and extracted data using methodological standards expected by Cochrane. We assessed risk of bias according to domains and risk of random errors with GRADE and Trial Sequential Analysis. We assessed the certainty of evidence using the GRADE approach.

MAIN RESULTS

We found two randomised clinical trials including 154 adult participants, aged between 18 years and 65 years, diagnosed with hepatosplenic schistosomiasis. One of the trials randomised participants to proximal splenorenal shunt versus distal splenorenal shunt versus oesophagogastric devascularisation with splenectomy, and the other randomised participants to distal splenorenal shunt versus oesophagogastric devascularisation with splenectomy. In both trials the diagnosis of hepatosplenic schistosomiasis was made based on clinical and biochemical assessments. The trials were conducted in Brazil and Egypt. Both trials were at high risk of bias.We are uncertain as to whether surgical portosystemic shunts improved all-cause mortality compared with oesophagogastric devascularisation with splenectomy due to imprecision in the trials (risk ratio (RR) 2.35, 95% confidence interval (CI) 0.55 to 9.92; participants = 154; studies = 2). We are uncertain whether serious adverse events differed between surgical portosystemic shunts and oesophagogastric devascularisation with splenectomy (RR 2.26, 95% CI 0.44 to 11.70; participants = 154; studies = 2). None of the trials reported on health-related quality of life. We are uncertain whether variceal rebleeding differed between surgical portosystemic shunts and oesophagogastric devascularisation with splenectomy (RR 0.39, 95% CI 0.13 to 1.23; participants = 154; studies = 2). We found evidence suggesting an increase in encephalopathy in the shunts group versus the devascularisation with splenectomy group (RR 7.51, 95% CI 1.45 to 38.89; participants = 154; studies = 2). We are uncertain whether ascites and re-interventions differed between surgical portosystemic shunts and oesophagogastric devascularisation with splenectomy. We computed Trial Sequential Analysis for all outcomes, but the trial sequential monitoring boundaries could not be drawn because of insufficient sample size and events. We downgraded the overall certainty of the body of evidence for all outcomes to very low due to risk of bias and imprecision.

AUTHORS' CONCLUSIONS

Given the very low certainty of the available body of evidence and the low number of clinical trials, we could not determine an overall benefit or harm of surgical portosystemic shunts compared with oesophagogastric devascularisation with splenectomy. Future randomised clinical trials should be designed with sufficient statistical power to assess the benefits and harms of surgical portosystemic shunts versus oesophagogastric devascularisations with or without splenectomy and with or without oesophageal transection.

Global epidemiology of viral hepatitis and national needs for complete control

INTRODUCTION

The World Health Organization recognizes that viral hepatitis is not only a massive public health issue but also a huge opportunity to improve quality of life and equity at a global level. Viral hepatitis causes about 1.5 million deaths each year and significantly affects the quality of life of hundreds of millions of people. To date, frail individuals in high-income countries and people living in low-income settings are paying the heaviest tool. Areas covered. Here we present a broad discussion on current knowledge and topical issues about the hepatitis pandemic. The report includes a structured overview of global epidemiology, including the definition of specific local epidemic profiles for each hepatitis agents (HAV, HBV, HCV, and HEV), and a perspective about the critical actions needed for achieving a complete control. Expert commentary. The control of viral hepatitis is currently, ethically urgent and even economically convenient. There is a wide consensus that viral hepatitis can be controlled through comprehensive intervention tailored on local needs addressing the issue of viral hepatitis as a unique public health issue. These strategies should include: (1) primary prevention (including vaccination and improved infection control), (2) improving diagnosis rate, and (3) management of existing cases of infections.

Systematic overview of hepatitis C infection in the Middle East and North Africa

AIM

To assess the quality of and to critically synthesize the available data on hepatitis C infections in the Middle East and North Africa (MENA) region to map evidence gaps.

METHODS

We conducted an overview of systematic reviews (SRs) following an a priori developed protocol (CRD42017076736). Our overview followed the preferred reporting items for systematic reviews and meta-analyses guidelines for reporting SRs and abstracts and did not receive any funding. Two independent reviewers systematically searched MEDLINE and conducted a multistage screening of the identified articles. Out of 5758 identified articles, 37 SRs of hepatitis C virus (HCV) infection in populations living in 20 countries in the MENA region published between 2008 and 2016 were included in our overview. The nine primary outcomes of interest were HCV antibody (anti-) prevalences and incidences in different at-risk populations; the HCV viremic (RNA positive) rate in HCV-positive individuals; HCV viremic prevalence in the general population (GP); the prevalence of HCV co-infection with the hepatitis B virus, human immunodeficiency virus, or schistosomiasis; the HCV genotype/subtype distribution; and the risk factors for HCV transmission. The conflicts of interest declared by the authors of the SRs were also extracted. Good quality outcomes reported by the SRs were defined as having the population, outcome, study time and setting defined as recommended by the PICOTS framework and a sample size > 100.

RESULTS

We included SRs reporting HCV outcomes with different levels of quality and precision. A substantial proportion of them synthesized data from mixed populations at differing levels of risk for acquiring HCV or at different HCV infection stages (recent and prior HCV transmissions). They also synthesized the data over long periods of time (e.g., two decades). Anti-HCV prevalence in the GP varied widely in the MENA region from 0.1% (study dates not reported) in the United Arab Emirates to 2.1%-13.5% (2003-2006) in Pakistan and 14.7% (2008) in Egypt. Data were not identified for Bahrain, Jordan, or Palestine. Good quality estimates of anti-HCV prevalence in the GP were reported for Algeria, Djibouti, Egypt, Iraq, Morocco, Pakistan, Syria, Sudan, Tunisia, and Yemen. Anti-HCV incidence estimates in the GP were reported only for Egypt (0.8-6.8 per 1000 person-year, 1997-2003). In Egypt, Morocco, and the United Arab Emirates, viremic rates in anti-HCV-positive individuals from the GP were approximately 70%. In the GP, the viremic prevalence varied from 0.7% (2011) in Saudi Arabia to 5.8% (2007-2008) in Pakistan and 10.0% (2008) in Egypt. Anti-HCV prevalence was lower in blood donors than in the GP, ranging from 0.2% (1992-1993) in Algeria to 1.7% (2005) in Yemen. The reporting quality of the outcomes in blood donors was good in the MENA countries, except in Qatar where no time framework was reported for the outcome. Some countries had anti-HCV prevalence estimates for children, transfused patients, contacts of HCV-infected patients, prisoners, sex workers, and men who have sex with men.

CONCLUSION

A substantial proportion of the reported outcomes may not help policymakers to develop micro-elimination strategies with precise HCV infection prevention and treatment programs in the region, as nowcasting HCV epidemiology using these data is potentially difficult. In addition to providing accurate information on HCV epidemiology, outcomes should also demonstrate practical and clinical significance and relevance. Based on the available data, most countries in the region have low to moderate anti-HCV prevalence. To achieve HCV elimination by 2030, up-to-date, good quality data on HCV epidemiology are required for the GP and key populations such as people who inject drugs and men who have sex with men.

Schistosoma mansoni and endocarditis: from egg to free DNA detection in Egyptian patients and infected BALB/c mice

With the growing incidence of closed schistosomiasis and uncommon presentations, there is a risk of the infection rate being underestimated. A study in Japan reported an unexplained case of endocarditis that was finally diagnosed as a complex Schistosoma japonicum infection; in the absence of advanced techniques, the diagnosis was delayed. We therefore set out to explore the incidence of Schistosoma mansoni in endocarditis patients coming from areas of Egypt where S. mansoni is endemic. We also investigated histopathological changes in the cardiac valves and the presence of cell-free parasite DNA (CFPD) in cardiac tissues of laboratory mice infected with S. mansoni. The study included 186 patients with the manifestations of infective endocarditis. Eggs were detected in the stool samples of 5.91% of patients. Seropositivity was reported in 23.66% of patients and antigen was detected in the urine samples of 10.21%. Using real-time polymerase chain reaction (PCR), CFPD was detected in the blood of 6.98% of the endocarditis patients and 95% of the infected mice, while the cardiac samples of 45% of the mice tested positive for CFPD (means ± SD = 1390.2 ± 283.65, 2158.72 ± 1103.1 and 5.71 ± 2.91, respectively). Histopathological examination revealed abnormal collagen deposition, inflammatory cells and haemorrhagic pigmentation in the heart sections. Despite the low incidence of S. mansoni infection in the studied cohort, the presence of CFPD in the cardiac tissue of infected mice makes it necessary to: (1) investigate the hazards of CFPD deposition in endothelium-rich organs; and (2) test the potential of CFPD to trigger tissue inflammation, abnormal proliferation or genome integration.

Co-infection of Schistosoma mansoni/hepatitis C virus and their associated factors among adult individuals living in fishing villages, north-western Tanzania

BACKGROUND

Schistosoma mansoni and Hepatitis C virus (HCV) are co-existence in sub-Saharan Africa and co-infection is common among humans population. The immunological responses characterized with Th₂-immune responses for S. mansoni and Th₁-immune responses for HCV are responsible for development hepatic morbidities in infected individuals. However, the co-occurrences of S. mansoni and HCV infection, their related ultrasound detectable morbidities and associated risk factors at community levels have not been examined in fishing communities, north-western Tanzania. In this context, the present study covers that gap.

METHODS

A cross-sectional study was conducted among 1924 asymptomatic individuals aged 15-55 years in four fishing villages (Igombe, Igalagala, Sangabuye and Kayenze) of Northwestern Tanzania. A single stool sample was collected from each study participants and examined for S. mansoni eggs using Kato Katz technique. Hepatitis C surface antigen (HCVsAg) was determined from a finger prick blood sample using a rapid test.

RESULTS

Overall, 51.8% (997/1924; 95%CI: 49.6-54.1) of the study participants were infected with S. mansoni and had a mean intensity of 223.7epg (95%; 202.4-247.1). Of the study participants, 90 (4.7%) were infected with hepatitis C virus (HCV). Overall, 2. 4% (47/1924) of the study participants were co-infected with S. mansoni and hepatitis C virus. Among the co-infected individuals, 42.6%, 70.2% and 19.1% had splenomegaly, hepatomegaly and periportal fibrosis (PPF). Factors associated with S. mansoni/HCV co-infection were being aged 26-35 years (aRR = 2.67, 95%CI: 1.03-6.93, P < 0.04), 46-55 years (aRR = 2.89, 95%CI: 1.10-7.57, P < 0.03) and having marked hepatomegaly (aRR = 2.32, 95%CI: 1.09-4.9, P < 0.03).

CONCLUSION

In this setting, S. mansoni and Hepatitis C are co-endemic and a proportion of individuals were co-infected. Hepatosplenic morbidities characterized with hepatomegaly, splenomegaly, hepatosplenomegaly and PPF were observed in co-infected individuals. These results highlight the need for integrated interventions measures against parasitic and viral diseases.

Diagnosis of coinfection by schistosomiasis and viral hepatitis B or C using 1H NMR-based metabonomics

BACKGROUND

Diagnosis of liver involvement due to schistosomiasis in asymptomatic patients from endemic areas previously diagnosed with chronic hepatitis B (HBV) or C (HCV) and periportal fibrosis is challenging. H-1 Nuclear Magnetic Resonance (NMR)-based metabonomics strategy is a powerful tool for providing a profile of endogenous metabolites of low molecular weight in biofluids in a non-invasive way. The aim of this study was to diagnose periportal fibrosis due to schistosomiasis mansoni in patients with chronic HBV or HCV infection through NMR-based metabonomics models.

METHODOLOGY/PRINCIPAL FINDINGS

The study included 40 patients divided into two groups: (i) 18 coinfected patients with schistosomiasis mansoni and HBV or HCV; and (ii) 22 HBV or HCV monoinfected patients. The serum samples were analyzed through H-1 NMR spectroscopy and the models were based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA). Ultrasonography examination was used to ascertain the diagnosis of periportal fibrosis. Exploratory analysis showed a clear separation between coinfected and monoinfected samples. The supervised model built from PLS-DA showed accuracy, R2 and Q2 values equal to 100%, 98.1% and 97.5%, respectively. According to the variable importance in the projection plot, lactate serum levels were higher in the coinfected group, while the signals attributed to HDL serum cholesterol were more intense in the monoinfected group.

CONCLUSIONS/SIGNIFICANCE

The metabonomics models constructed in this study are promising as an alternative tool for diagnosis of periportal fibrosis by schistosomiasis in patients with chronic HBV or HCV infection from endemic areas for Schistosoma mansoni.

Coinfection of Schistosoma Species with Hepatitis B or Hepatitis C Viruses

Although a considerable number of studies have been undertaken to date, it is still controversial as to whether or not coinfection with schistosomiasis increases the susceptibility to or progression from Hepatitis B virus (HBV) or Hepatitis C virus (HCV) infection. This review is a closer examination of the key studies conducted on human populations on clinical factors that were published in English between 1975 and January 2015. Our review is mainly based on tables containing the salient information, which are arranged first by study population, country of study and publication date. We provide further explanation, clarification and discussion in the text. As such, it includes both studies that have been conducted on general populations who are largely asymptomatic for clinical disease (Table 3), as well as those focussing on special populations, which are usually comprised of clinical patients. These special populations have been presented as follows: subjects with chronic liver disease or related conditions such as cirrhosis, Table 4; subjects with primary liver cancer, Table 5; subjects with schistosomiasis, Table 6; subjects with acute or chronic hepatitis resulting from HBV, Table 7 and, subjects with HCV, Table 8. We have presented studies that compared two mono-infected groups with one that is coinfected separately in Table 9, as these offer us the best basis from which to evaluate if any synergistic effects accompany coinfection. A number of factors contributed to the results reported in our tables. These included, but are not limited to: subject selection (i.e. asymptomatic cases typically drawn from the general population vs subjects presenting to a hospital or clinic with clinical disease); study design, which directly impacts our ability to infer causality (i.e. case series, cross-sectional, case-control, cohort study); use and choice of control population (i.e. apparently healthy subjects vs other hospital patients vs none); sample size, which directly impacts statistical power and can result in a Type II error; geographic area, which may reflect differences in population genetics, public health history, environmental differences or any number of other important factors (i.e. Egypt, Brazil, China); method of testing for schistosomal infections (i.e. stool vs antibody test); method of testing to determine if advanced schistosomal disease was present (i.e. ultrasound, liver biopsy vs none); method of serological testing for HBV (i.e. use of HBsAg alone or with other markers or DNA testing); method of serological testing for HCV (i.e. use of anti-HCV alone or with RNA testing) and, year of the study, which reflects among other things, technological improvements between tests as well as possible changes in the frequency of exposure in the populations under study (i.e. use of parenteral antischistosomal therapy vs the oral antischistosomal medication). Despite all these differences, throughout this review we have observed general patterns that seem largely consistent with one another. Studies conducted on general, largely asymptomatic populations tend to support the view that having one of the diseases in question (i.e. schistosomiasis) does not necessarily predispose one to becoming coinfected with another (i.e. HBV or HCV). Rather, the probability of becoming coinfected seems most closely associated with modes of transmission for either HBV or HCV in schistosome-endemic areas, such as the past use of parenteral antischistosomal therapy or frequent blood transfusion. Once coinfected, however, the clinical course of illness for those with Schistosoma-HBV or Schistosoma-HCV infections are typically much more severe than for mono-infected subjects. The strongest evidence for this was found in the half-dozen or so prospective cohort studies that systematically monitored disease progression in their subjects. With respect to HBV infection, coinfection with Schistosoma prolonged the carriage state and more often resulted in chronic hepatitis with greater cirrhosis as well as higher mortality. Much of the same was also observed with respect to HCV, where coinfection with Schistosoma was associated with a reduced ability to spontaneously resolve the viral infection and more often resulted in rapid fibrosis as well as higher mortality. Furthermore, two of these studies which were fully comparative in nature, support the supposition that there is a synergistic association between Schistosoma-HCV for both liver fibrosis and mortality. Immunological studies, all conducted on HCV, also generally seem to support this. The results of our research argue for greater primary prevention for both HBV and HCV in Schistosoma-endemic populations. Although no vaccine currently exists for HCV as it does for HBV, additional steps can still be taken to reduce transmission in high-risk populations. Greater use of the HBV vaccine is particularly advisable. Finally, additional observational, longitudinal studies conducted on human populations that are fully comparative in nature could help answer some of the remaining questions on both Schistosoma-HBV as well as Schistosoma-HCV coinfections. Some of these include the role of active versus past schistosomal infections, the role of genetic variants, as well as the effect of coinfection on treatment. Future studies should make a particular effort to use a sufficient sample size to ensure adequate statistical power, which was not often properly considered in many of the studies we reviewed for this paper.