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

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.

Managing cirrhosis with limited resources: perspectives from sub-Saharan Africa

Cirrhosis represents the end stage of chronic liver disease. Sub-Saharan Africa, a resource-constrained region, has a high burden of chronic liver disease, with causes including chronic viral hepatitis, excessive alcohol use, and metabolic dysfunction-associated steatotic liver disease (MASLD), the risk of which is burgeoning. The development of liver cirrhosis predicts for morbidity and mortality, driven by both liver dysfunction and the consequences of portal hypertension. Compensated cirrhosis portends a better prognosis than decompensated cirrhosis, highlighting the need for the early diagnosis of cirrhosis and its causes. With resource challenges, the diagnosis and management of cirrhosis is demanding, but less costly and less invasive interventions with substantial benefits, ranging from simple blood tests to transient elastography, are feasible in such settings. Simple interventions are also available to manage the complex manifestations of decompensation, such as β blockers in variceal bleeding prophylaxis, salt restriction and appropriate diuretic use in ascites, and lactulose and generic rifaximin in hepatic encephalopathy. Ultimately, managing the underlying causative factors of liver disease is key in improving prognosis. Management demands expanded policy interventions to increase screening and treatment for hepatitis B and C and reduce alcohol use and the metabolic factors driving MASLD. Furthermore, the skills needed for more specialised interventions, such as transjugular intrahepatic portosystemic shunt procedures and even liver transplantation, warrant planning, increased capacity, and support for regional centres of excellence. Such centres are already being developed in sub-Saharan Africa, demonstrating what can be achieved with dedicated initiatives and individuals.

Transmission-Blocking Vaccines against Schistosomiasis Japonica

Control of schistosomiasis japonica, endemic in Asia, including the Philippines, China, and Indonesia, is extremely challenging. Schistosoma japonicum is a highly pathogenic helminth parasite, with disease arising predominantly from an immune reaction to entrapped parasite eggs in tissues. Females of this species can generate 1000-2200 eggs per day, which is about 3- to 15-fold greater than the egg output of other schistosome species. Bovines (water buffalo and cattle) are the predominant definitive hosts and are estimated to generate up to 90% of parasite eggs released into the environment in rural endemic areas where these hosts and humans are present. Here, we highlight the necessity of developing veterinary transmission-blocking vaccines for bovines to better control the disease and review potential vaccine candidates. We also point out that the approach to producing efficacious transmission-blocking animal-based vaccines before moving on to human vaccines is crucial. This will result in effective and feasible public health outcomes in agreement with the One Health concept to achieve optimum health for people, animals, and the environment. Indeed, incorporating a veterinary-based transmission vaccine, coupled with interventions such as human mass drug administration, improved sanitation and hygiene, health education, and snail control, would be invaluable to eliminating zoonotic schistosomiasis.

Schistosoma mansoni infection alters the host pre-vaccination environment resulting in blunted Hepatitis B vaccination immune responses

Schistosomiasis is a disease caused by parasitic flatworms of the Schistosoma spp., and is increasingly recognized to alter the immune system, and the potential to respond to vaccines. The impact of endemic infections on protective immunity is critical to inform vaccination strategies globally. We assessed the influence of Schistosoma mansoni worm burden on multiple host vaccine-related immune parameters in a Ugandan fishing cohort (n = 75) given three doses of a Hepatitis B (HepB) vaccine at baseline and multiple timepoints post-vaccination. We observed distinct differences in immune responses in instances of higher worm burden, compared to low worm burden or non-infected. Concentrations of pre-vaccination serum schistosome-specific circulating anodic antigen (CAA), linked to worm burden, showed a significant bimodal distribution associated with HepB titers, which was lower in individuals with higher CAA values at month 7 post-vaccination (M7). Comparative chemokine/cytokine responses revealed significant upregulation of CCL19, CXCL9 and CCL17 known to be involved in T cell activation and recruitment, in higher CAA individuals, and CCL17 correlated negatively with HepB titers at month 12 post-vaccination. We show that HepB-specific CD4+ T cell memory responses correlated positively with HepB titers at M7. We further established that those participants with high CAA had significantly lower frequencies of circulating T follicular helper (cTfh) subpopulations pre- and post-vaccination, but higher regulatory T cells (Tregs) post-vaccination, suggesting changes in the immune microenvironment in high CAA could favor Treg recruitment and activation. Additionally, we found that changes in the levels of innate-related cytokines/chemokines CXCL10, IL-1β, and CCL26, involved in driving T helper responses, were associated with increasing CAA concentration. This study provides further insight on pre-vaccination host responses to Schistosoma worm burden which will support our understanding of vaccine responses altered by pathogenic host immune mechanisms and memory function and explain abrogated vaccine responses in communities with endemic infections.

The role of helminths in the development of non-communicable diseases

Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.

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.

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.

Co-infection and Risk Factors Associated with STIs among Pregnant Women in Rural Health Facilities in Nigeria: A Retrospective Study

Globally, sexually transmitted infections are recognized as a public and reproductive health challenge. The study determined the prevalence, co-infection, and risk factors associated with HBV, HCV, HIV, and Syphilis infections among pregnant women receiving antenatal care in rural health facilities in Ebonyi State, Nigeria. A retrospective study was conducted from January to December 2018 in 8 primary healthcare facilities using antenatal records of all the 4657 pregnant women who attended ANC within the period. Data were analyzed using descriptive and inferential statistics with IBM SPSS statistics version 20 and hypotheses tested at P < .05. The findings indicated a medium prevalence of HBV (4.1%), a high prevalence of HCV (4.1%) and syphilis (1.8%), and a low prevalence of HIV (0.9%). An overall co-infection rate of 0.623% that was not significant (P > .05) was observed. Also, prevalence was more among the younger mothers (<20 years), those with secondary education. And the history of blood transfusion was significantly associated with HBV and HCV prevalence (χ2 = 7.865; P = .05*), 11.8%. conclusively, due to medium HBV prevalence and a high prevalence of HCV and syphilis observed, attention should be paid to blood screening before transfusion by health workers. Relevant stakeholders should provide intensive health education and appropriate free treatment services particularly for younger mothers and the less educated.

Single oral fixed-dose praziquantel-miltefosine nanocombination for effective control of experimental schistosomiasis mansoni

Background

The control of schistosomiasis has been centered to date on a single drug, praziquantel, with shortcomings including treatment failure, reinfection, and emergence of drug resistance. Drug repurposing, combination therapy or nanotechnology were explored to improve antischistosomal treatment. The aim of the present study was to utilize a novel combination of the three strategies to improve the therapeutic profile of praziquantel. This was based on a fixed-dose nanocombination of praziquantel and miltefosine, an antischistosomal repurposing candidate, co-loaded at reduced doses into lipid nanocapsules, for single dose oral therapy.

Methods

Two nanocombinations were prepared to provide 250 mg praziquantel-20 mg miltefosine/kg (higher fixed-dose) or 125 mg praziquantel-10 mg miltefosine/kg (lower fixed-dose), respectively. Their antischistosomal efficacy in comparison with a non-treated control and their praziquantel or miltefosine singly loaded counterparts was assessed in murine schistosomiasis mansoni. A single oral dose of either formulation was administered on the initial day of infection, and on days 21 and 42 post-infection. Scanning electron microscopic, parasitological, and histopathological studies were used for assessment. Preclinical data were subjected to analysis of variance and Tukeyʼs post-hoc test for pairwise comparisons.

Results

Lipid nanocapsules (~ 58 nm) showed high entrapment efficiency of both drugs (> 97%). Compared to singly loaded praziquantel-lipid nanocapsules, the higher nanocombination dose showed a significant increase in antischistosomal efficacy in terms of statistically significant decrease in mean worm burden, particularly against invasive and juvenile worms, and amelioration of hepatic granulomas (P ≤ 0.05). In addition, scanning electron microscopy examination showed extensive dorsal tegumental damage with noticeable deposition of nanostructures.

Conclusions

The therapeutic profile of praziquantel could be improved by a novel multiple approach integrating drug repurposing, combination therapy and nanotechnology. Multistage activity and amelioration of liver pathology could be achieved by a new praziquantel-miltefosine fixed-dose nanocombination providing 250 mg praziquantel-20 mg miltefosine/kg. To the best of our knowledge, this is the first report of a fixed-dose nano-based combinatorial therapy for schistosomiasis mansoni. Further studies are needed to document the nanocombination safety and explore its prophylactic activity and potential to hinder the onset of resistance to the drug components.

Can Early Diagnosis of Varices, Regular Praziquantel, and Reduction of Hepatitis Coinfection Reduce Mortality among Patients Attended for Periportal Fibrosis in Northwestern Tanzania? A Case-Control Study

Background

Schistosoma mansoni is highly endemic in the Lake Zone part of Tanzania and most people are chronically infected. Periportal fibrosis (PPF) is the commonest complication of chronic S. mansoni infection documented in up to 42% of studied participants in the community-based studies. These patients are at high risk of mortality since most of them are diagnosed late with bleeding varices. At Bugando, Schistosoma-related varices contributed to 70% of patients admitted due to vomiting blood with a two months' mortality of over 10%. Earlier studies had reported higher mortality of up to 29% among patients with PPF even with the best in-hospital care. Understanding factors that increased the risk of mortality is important clinically in devising ways that can improve the outcome of this subgroup of patients.

Methods

A retrospective analysis of patients with PPF from 2015 through 2018 was done. Their sociodemographic, clinical, laboratory, ultrasonographic, endoscopic, and survival status data were collected for analysis. STATA 13 was used for analysis, the prevalence of varices, active schistosomiasis, and hepatitis B coinfection was determined. Cumulative mortality as a major outcome was also determined, and factors associated with increased risk of mortality were assessed by a logistic regression model.

Results

In total, 250 participants were included in this analysis. Majority, 222 (88.8%; 95% CI: 84.2-92.4) had active S. mansoni infection, and 40 (16.0%; 95% CI: 11.6-21.1) had S. mansoni-HBV coinfection. Cumulatively, 39 (15.6%; 95% CI: 11.3-20.7) patients died, with most deaths, 31 (79.5%; 95% CI: 63.5-90.7) occurring within two years following the diagnosis of PPF (chi² = 6.3; p = 0.012). The odds of mortality were independently associated with fishing (OR: 10.8; 95% CI: 2.2-52; p = 0.003), upper gastro intestinal bleeding (OR: 2.4; 95% CI: 1.1-5.4; p = 0.037), HBV coinfection (OR: 3.3; 95% CI: 1.2-91; p = 0.019), and ascites (OR: 3.3; 95% CI: 1.3-8.2; p = 0.010).

Conclusions

In this, S. mansoni endemic area, varices, actives schistosomiasis, hepatitis B coinfection, and mortality are highly common. Screening for varices and initiation of prophylaxis, administration of praziquantel, and screening for hepatitis B should be part and parcel of care of these patients. The first two years of diagnosis, patients are at high risk of mortality; risk factors in this study should assist planning a closer follow-up of patients at risk of mortality to improve their long-term outcome.