The association of Schistosoma and geohelminth infections with ß-cell function and insulin resistance among HIV-infected and HIV-uninfected adults: A cross-sectional study in Tanzania.

OBJECTIVES: Data on the role of helminths on diabetes in Africa are limited. We investigated whether Schistosoma and geohelminth infections are associated with ß-cell function and insulin resistance among adults. METHODS: A cross-sectional study was conducted among adults during 2016-2017. Demography, Schistosoma and geohelminth infections, HIV and insulin data were collected. Insulin during an oral glucose tolerance test (fasting, 30, and 120-min), overall insulin secretion index, insulinogenic index, HOMA-ß, and HOMA-IR were main outcome measures for ß-cell function and insulin resistance, respectively. Generalized estimating equations and generalized linear models assessed the association of Schistosoma and geohelminth infections with outcome measures separately by HIV status. Outcomes were presented as marginal means with 95% CI. RESULTS: Data were obtained for 1718 participants. Schistosoma infection was associated with higher 30-min insulin (24.2 mU/L, 95% CI: 6.9, 41.6) and overall insulin secretion index (13.3 pmol/L/mmol/L; 3.7, 22.9) among HIV-uninfected participants but with lower fasting insulin (-0.9 mU/L; -1.6, -0.2), 120-min insulin (-12.0 mU/L; -18.9, -5.1), and HOMA-IR (-0.3 mmol/L; -0.6, -0.05) among HIV-infected participants not yet on antiretroviral therapy (ART). Among HIV-infected participants not on ART, geohelminth infection was associated with lower fasting insulin (-0.9 mU/L; -1.6, -0.2), 120-min insulin (-9.1 mU/L; -17.3, -1.0), HOMA-ß (-8.9 mU/L)/(mmol/L; -15.3, -2.6) and overall insulin release index (-5.1 pmol/L/mmol/L; -10.3, 0.02), although this was marginally significant. There was no association among those on ART. CONCLUSIONS: Schistosoma infection was associated with higher ß-cell function among HIV-uninfected participants whereas Schistosoma and geohelminth infections were associated with reduced ß-cell function among HIV-infected participants not on ART.

Prediction of minimal hepatic encephalopathy by using an radiomics nomogram in chronic hepatic schistosomiasis patients.

OBJECTIVE: To construct an MR-radiomics nomogram to predict minimal hepatic encephalopathy (MHE) in patients with chronic hepatic schistosomiasis (CHS). METHODS: From July 2017 to July 2020, 236 CHS patients with non-HE (n = 140) and MHE (n = 96) were retrospective collected and randomly divided into training group and testing group. Radiomics features were extracted from substantia nigra-striatum system of a brain diffusion weighted images (DWI) and combined with clinical predictors to build a radiomics nomogram for predicting MHE in CHS patients. The ROC curve was used to evaluate the predicting performance in training group and testing group. The clinical decisive curve (CDC) was used to assess the clinical net benefit of using radiomics nomogram in predicting MHE. RESULTS: Low seralbumin (P < 0.05), low platelet count (P < 0.05) and high plasma ammonia (P < 0.05) was the significant clinical predictors for MHE in CHS patients. The AUC, specificity and sensitivity of the radiomics nomogram were 0.89, 0.90 and 0.86 in the training group, and were 0.83, 0.85 and 0.75 in the training group. The CDC analysis showed clinical net benefits for the radiomics nomogram in predicting MHE. CONCLUSIONS: The radiomics nomogram combining DWI radiomics features and clinical predictors could be useful tool to predict MHE in CHS patients.

Identification of Low Molecular Weight Proteins and Peptides from Schistosoma mekongi Worm, Egg and Infected Mouse Sera.

Schistosoma mekongi is found in the lower Mekong river region and causes schistosomiasis. Low sensitivity of diagnosis and development of drug resistance are problems to eliminate this disease. To develop novel therapies and diagnostics for S. mekongi, the basic molecular biology of this pathogen needs to be explored. Bioactive peptides have been reported in several worms and play important roles in biological functions. Limited information is available on the S. mekongi peptidome. Therefore, this study aimed to identify S. mekongi peptides using in silico transcriptome mining and mass spectrometry approaches. Schistosoma peptide components were identified in adult worms, eggs, and infected mouse sera. Thirteen neuropeptide families were identified using in silico predictions from in-house transcriptomic databases of adult S. mekongi worms. Using mass spectrometry approaches, 118 peptides (from 54 precursor proteins) and 194 peptides (from 86 precursor proteins) were identified from adult worms and eggs, respectively. Importantly, eight unique peptides of the S. mekongi ubiquitin thioesterase, trabid, were identified in infected mouse sera 14, 28, and 56 days after infection. This protein may be a potential target for diagnosis of schistosomiasis. The S. mekongi peptide profiles determined in this study could be used for further drug and diagnostic development.

Evaluation of microscopy, serology, circulating anodic antigen (CAA), and eosinophil counts for the follow-up of migrants with chronic schistosomiasis: a prospective cohort study.

BACKGROUND: An accurate test for the diagnosis and post-treatment follow-up of patients with schistosomiasis is needed. We assessed the performance of different laboratory parameters, including the up-converting reporter particle technology lateral flow assay to detect circulating anodic antigen (UCP-LF CAA), for the post-treatment follow-up of schistosomiasis in migrants attending a dedicated outpatient clinic in a non-endemic country. METHODS: Routine anti-Schistosoma serology results and eosinophil counts were obtained of patients with positive urine/stool microscopy and/or PCR (confirmed cases) or only positive serology (possible cases), and at least one follow-up visit at 6 (T6) or 12 (T12) months after praziquantel treatment. All sera samples were tested with the UCP-LF CAA assay. RESULTS: Forty-eight patients were included, 23 confirmed and 25 possible cases. The percentage seropositivity and median antibody titers did not change significantly during follow-up. UCP-LF CAA was positive in 86.9% of confirmed and 20% of possible cases. The percentage positivity and median CAA levels decreased significantly post-treatment, with only two patients having positive CAA levels at T12. CONCLUSIONS: The UCP-LF CAA assay proved useful for the diagnosis of active infection with Schistosoma spp. and highly valuable for post-treatment monitoring in migrants, encouraging the development of a commercial test.

Prevalence of schistosomiasis and its association with anemia among pregnant women: a systematic review and meta-analysis.

BACKGROUND: Schistosomiasis is a highly prevalent parasitic disease that can lead to adverse maternal and perinatal outcomes. To our knowledge, there has been no systematic review and meta-analysis of schistosomiasis during pregnancy. METHODS: We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant published studies were searched in international databases (PubMed, Science Direct, Scopus, Web of Science, and Google Scholar), from their inception until May 31, 2020. The retrieved studies were assessed for quality using the Modified Newcastle-Ottawa Scale. OpenMeta Analyst software was used for the statistical analysis. RESULTS: Thirty-two studies enrolling 21024 pregnant women were included in this meta-analysis. All 32 of these studies were conducted in Africa. Of these studies, 19, 11, and 2 investigated S. mansoni, S. haematobium, and combined S. mansoni and S. haematobium infections, respectively. The pooled prevalence estimate of schistosomiasis during pregnancy was 13.2% (95 CI 11.0-15.4). A random model was used because of high heterogeneity (Q = 99.14; P < 0.001). In subgroup analyses, the pooled prevalence estimate of S. haematobium was significantly higher than the pooled prevalence estimates of S. mansoni [22.5% (95% CI 1.6-43.5) vs 8.7% (95% CI 6.0-11.3, P = 0.016), respectively]. The results of meta-regression analyses showed a non-significant difference in the prevalence of schistosomiasis during pregnancy according to the study sample sizes and year of publication. Only six studies evaluated the association between schistosomiasis during pregnancy and anemia. Schistosomiasis was associated with anemia in these six studies (OR = 3.02, 95% = 1.25‒7.28, P = 0.014). CONCLUSION: The present meta-analysis suggests that schistosomiasis during pregnancy is an existing health problem. This meta-analysis also highlights the lack of data on the determinants and outcomes of schistosomiasis during pregnancy. Preventive measures are needed and could be part of antenatal care in areas endemic with schistosomiasis.

[Clinical characteristics and distribution of peripheral T lymphocyte subsets in patients with schistosomal hepatic diseases in Suzhou City].

OBJECTIVE: To investigate the clinical characteristics and the distribution of peripheral blood T lymphocyte sub-sets in patients with schistosomal hepatic cirrhosis in Suzhou City. METHODS: A total of 32 inpatients with liver diseases due to advanced schistosomiasis at the Department of Infectious Diseases, The First Affiliated Hospital of Soochow University from January 2016 to January 2018 were recruited and assigned into the infection and non-infection groups according to presence of co-infections, and 20 old healthy volunteers served as controls. Venous blood samples were collected on the day of admission, and the proportions of CD4+ T cells, CD8+ T cells, regulatory T (Treg) cells and Th17 cells were detected in peripheral blood using flow cytometry. RESULTS: Most patients with liver disorders due to advanced schistosomiasis were admitted to hospital in Suzhou City because of portal hypertension-associated complications, with a high prevalence of co-infections (59.38%, 19/32). The proportions of peripheral CD4+ and CD8+ T cells and Th17 cells were all significantly lower in patients with liver disorders due to advanced schistosomiasis than in controls (t = -5.111, -4.470 and -2.749, all P < 0.05), and a higher proportion of Treg cells was detected in patients than in controls (t = 5.628, P < 0.05). In addition, there were significant differences among the infection group, non-infection group and controls in terms of the percentage of CD4+ T cells, CD8+ T cells, Th17 cells and Treg cells (F = 15.837, 16.594, 9.290 and 27.866, all P < 0.05). CONCLUSIONS: Portal hypertension-associated complications are predominantly seen in patients with liver diseases due to advanced schistosomiasis at admission in Suzhou City, and co-infections are common. Imbalance of peripheral T cell subsets is detected in patients with liver diseases due to advanced schistosomiasis in Suzhou City.

Placental gene expression and antibody levels of mother-neonate pairs reveal an enhanced risk for inflammation in a helminth endemic country.

In utero exposure to environmental factors can modify the development of allergies later in life whereby the mechanisms of the feto-maternal crosstalk still remain largely unknown. Murine studies revealed that inflammatory maternal signals elicited by chronic helminth infection within the placenta imprint a distinct gene expression profile related to the Vitamin-D-receptor (VDR)-inflammation-axis. We thus investigated whether pro- or anti- inflammatory immune responses as well as VDR and related gene expression within the placenta differ between women from helminth-endemic and non-endemic areas. A prospective pilot study was conducted in Munich, Germany (helminth non-endemic) and Lambaréné, Gabon (helminth-endemic). At delivery, clinical information alongside placenta tissue samples and maternal and cord blood were obtained for further laboratory analysis. Schistosoma haematobium infection was detected in 13/54 (23%) Gabonese women. RT PCR revealed significantly lower gene expression of VDR, Cyp27b1, Foxp3 and IL10 in Gabonese compared to German placentae as well as significantly lower levels of plasma IgG4 in newborns resulting in a significantly higher IgE/IgG4 ratio. These findings demonstrate that exposure in utero to different environments alters placental gene expression and thus possibly plays a role in the development and modulation of the immune system of the offspring.

[Analysis of endemic situation of schistosomiasis based on geographic information system (GIS) in Wuhan City in 2017].

OBJECTIVE: To analyze the endemic sitaution of schistosomiasis based on geographic information system (GIS) in Wuhan City in 2017, so as to provide the reference for further schistosomiasis control activities. METHODS: According to the data of the annual report on the prevention and control of schistosomiasis in Wuhan City in 2017, the spatial database regarding the endemic situation of schistosomiasis was established and analyzed by ArcMap 10.2. RESULTS: The 593 schistosomiasis-endemic villages in Wuhan City were mainly located in the Yangtze River and its major tributaries. Kernel density analysis showed that the endemic villages of three regions with the highest density was located in the west of Caidian District (Zhuru Street), the east of Hannan District (Shamao Street) and the southwest corner of Xinzhou District (Yangluo Street). The sero-positive population was densely distributed in the West of Caidian District (Zhuru Street), which accounted for 34.23% of all seruo-positives in the city. There were 492 farming cattle fenced in Donggan Village in Hongbei Street of Caidian District. A higher density of the area with Oncomelania hupensis snails was located in the southwest region of Caidian District (Xiaosi Street), accounting for 31.22% of the total area with snails. In 2017, the re-emerging area with snails was 36.60 hm2. The high kernel density region with snails was located in Zhuru Street of Caidian District. The region with high density of living snails was located in the central region of Hannan District (Hongbei Production Brigade), the average density of living snails was 0.36 snails/0.1 m2. CONCLUSIONS: The endemic situation of schistosomiasis is at a low level in Wuhan City, and the spatial distribution is not uniform. In some local areas, the historical endemic situation of schistosomiasis is serious and the high risk factors are more concentrated. It is necessary to strengthen the surveillance of schistosomiasis.

Identification of newly developed advanced schistosomiasis with MALDI-TOF mass spectrometry and ClinProTools analysis.

Cases of newly developed advanced schistosomiasis (NDAS) have occurred in areas where schistosomiasis transmission has been blocked for more than 25 years. The causes and pathogenesis of NDAS are still unknown. Diagnosis of NDAS relies on historical investigation and clinical symptoms, such as liver fibrosis, hepatic ascites and abnormal biochemical indexes in serum. It is important but difficult at this stage to develop a new tool for early screening and rapid diagnosis. In this study, serum peptides from thirty patients with NDAS and thirty healthy controls were captured with weak cation exchange magnetic beads, and subjected to MALDI-TOF mass spectrometry and ClinProTools analysis. Eleven peaks with m/z 924, 2661, 2953, 2991, 3241, 3884, 5337, 5905, 5943, 7766 and 9289 were decreased and three peaks with m/z 1945, 2082 and 4282 were increased in the NDAS group. The proteomic detection pattern (PDP) was established with 14 different peptide peaks, and its sensitivity and specificity were investigated with a blind test. The peptide mass fingerprints of sera from 50 NDAS patients and 100 healthy controls were double-blind subjected to the PDP method, and 50 patients and 92 healthy controls were classified as NDAS and healthy separately, which showed 100% sensitivity and 92% specificity. Our results showed that the PDP could be a new and useful method to detect NDAS.

[Surveillance of schistosomiasis in a national surveillance site of Jurong City, 2015-2017].

OBJECTIVE: To understand the endemic situation and control effect of schistosomiasis through the surveillance in a national surveillance site of Jurong City, so as to provide the evidence for formulating the prevention and control measures. METHODS: According to the National Schistosomiasis Monitoring Scheme (2014 Edition), the surveillance of schistosome infection in Oncomelania hupensis snails, residents and livestock was performed in the Kongqing Village, a national surveillance site of Jurong City, from 2015 to 2017. RESULTS: The areas with snails were 0, 0, and 0.63 hm2 in 2015, 2016, and 2017 respectively; the average densities of living snails were 0, 0, and 0.19 snails/0.1 m2 in 2015, 2016, and 2017 respectively. No schistosome-infected snails were found. The positive rates of blood tests for schistosomiasis in the local residents were 7.72%, 7.45% and 3.45%, and the positive rates of blood tests in the floating population were 4.90%, 3.47% and 0.97% in 2015, 2016 and 2017, respectively. No positives were found in the schistosome etiology detection in the crowd and livestock. CONCLUSIONS: The effect of schistosomiasis prevention and control is obvious in Jurong City, but O. hupensis snails are still of recurrence. Therefore, the monitoring and control efforts should be strengthened to consolidate the achievements of schistosomiasis prevention and control.

Prevalence of strongyloidiasis and schistosomiasis among migrants: a systematic review and meta-analysis.

BACKGROUND: Global migration from regions where strongyloidiasis and schistosomiasis are endemic to non-endemic countries has increased the potential individual and public health effect of these parasitic diseases. We aimed to estimate the prevalence of these infections among migrants to establish which groups are at highest risk and who could benefit from screening. METHODS: We did a systematic review and meta-analysis of strongyloidiasis and schistosomiasis prevalence among migrants born in endemic countries. Original studies that included data for the prevalence of Strongyloides or Schistosoma antibodies in serum or the prevalence of larvae or eggs in stool or urine samples among migrants originating from countries endemic for these parasites and arriving or living in host countries with low endemicity-specifically the USA, Canada, Australia, New Zealand, Israel, and 23 western European countries-were eligible for inclusion. Pooled estimates of the prevalence of strongyloidiasis and schistosomiasis by stool or urine microscopy for larvae or eggs or serum antibodies were calculated with a random-effects model. Heterogeneity was explored by stratification by age, region of origin, migrant class, period of study, and type of serological antigen used. FINDINGS: 88 studies were included. Pooled strongyloidiasis seroprevalence was 12·2% (95% CI 9·0-15·9%; I2 96%) and stool-based prevalence was 1·8% (1·2-2·6%; 98%). Migrants from east Asia and the Pacific (17·3% [95% CI 4·1-37·0]), sub-Saharan Africa (14·6% [7·1-24·2]), and Latin America and the Caribbean (11·4% [7·8-15·7]) had the highest seroprevalence. Pooled schistosomiasis seroprevalence was 18·4% (95% CI 13·1-24·5; I2 97%) and stool-based prevalence was 0·9% (0·2-1·9; 99%). Sub-Saharan African migrants had the highest seroprevalence (24·1·% [95% CI 16·4-32·7]). INTERPRETATION: Strongyloidiasis affects migrants from all global regions, whereas schistosomiasis is focused in specific regions and most common among sub-Saharan African migrants. Serological prevalence estimates were several times higher than stool estimates for both parasites. These data can be used to inform screening decisions for migrants and support the use of serological screening, which is more sensitive and easier than stool testing. FUNDING: None.

[Serum vitamin D expression in advanced schistosomiasis patients with hepatic fibrosis and its association with disease progression].

OBJECTIVE: To compare the expression of serum vitamin D in advanced schistosomiasis patients with grade I and II hepatic fibrosis, and to preliminarily examine its associations with the internal diameter of the main portal vein and progression of hepatic fibrosis. METHODS: The medical records of 126 advanced schistosomiasis patients with grade I and II hepatic fibrosis referred to Jiaxing First Hospital from March 2012 to September 2015 were retrospectively analyzed. The internal diameter of the main portal vein and serum 25-hydroxyvitamin D3 [25(OH)D3] level were measured. The progression of hepatic fibrosis was followed up, and the serum vitamin D level was compared between patient with disease progression and stable disease. RESULTS: The 126 advanced schistosomiasis patients included 72 men and 54 women, and had ages of 62 to 80 years. There were 58 cases with grade I hepatic fibrosis and 68 cases with grade II hepatic fibrosis. There were significant differences between patients with grade I and II hepatic fibrosis in terms of hemoglobin, white blood cell count, prothrombin time, international normalized ratio, activated partial thromboplastin time, fibrinogen or 25(OH)D3 level (all P > 0.05), and significant differences were seen in alanine aminotransferase, aspartate aminotransferase, blood calcium, blood phosphorus levels and the internal diameter of the main portal vein (all P values < 0.05). In addition, a lower serum 25(OH)D3 level was detected in patients with broadened internal diameter of the main portal vein than in those with normal internal diameter of the main portal vein [(19.08 ± 1.36) nmol/L vs. (25.61 ± 6.69) nmol/L, P < 0.05]. Following 3-year follow-up, there were 73 cases with progression of hepatic fibrosis, and a significantly lower serum vitamin D level was found in patients with disease progression than in those with stable disease [(20.00 ± 0.81) nmol/L vs. (25.47 ± 5.91) nmol/L, P < 0.05]. CONCLUSIONS: Vitamin D deficiency is common in advanced schistosomiasis patients with hepatic fibrosis, and it may be associated with the internal diameter of the main portal vein and the progression of hepatic fibrosis disease.

Improved diagnosis of active Schistosoma infection in travellers and migrants using the ultra-sensitive in-house lateral flow test for detection of circulating anodic antigen (CAA) in serum.

Schistosomiasis is a parasitic disease affecting over 250 million people in the tropics. In non-endemic regions, imported Schistosoma infections are commonly diagnosed by serology, but based on antibody detection an active infection cannot be distinguished from a cured infection and it may take more than 8 weeks after exposure before seroconversion occurs. In endemic populations, excellent results have been described in diagnosing low-grade active Schistosoma infections by the detection of the adult worm-derived circulating anodic antigen (CAA) utilising robust lateral flow (LF) assays combined with up-converting phosphor (UCP) reporter technology. The purpose of this study is to explore the diagnostic value of the UCP-LF CAA assay in a non-endemic setting. CAA concentrations were determined in 111 serum samples originating from 81 serology-positive individuals. In nine individuals, serum could be collected before travel and an additional five provided samples before and after seroconversion occurred. Based on detectable CAA levels, an active infection was seen in 56/81 (69%) of the exposed individuals, while the 10 controls and the 9 sera collected before travel were tested negative for CAA. Positive CAA levels were observed starting 4 weeks after exposure and in four cases CAA was detected even before Schistosoma-specific antibodies became positive. Higher serum CAA levels were seen in migrants than in travellers and CAA concentrations dropped sharply when testing follow-up samples after treatment. This explorative study indicates the UCP-LF CAA serum assay to be a highly accurate test for detecting active low-grade Schistosoma infections in a non-endemic routine diagnostic setting.

[Strategy of transmission interruption of schistosomiasis and its effects in Runzhou District, Zhenjiang City, Jiangsu Province].

OBJECTIVE: To evaluate the effects of the strategy of transmission interruption of schistosomiasis in Runzhou District, Zhenjiang City, Jiangsu Province. METHODS: The comprehensive prevention and control strategy was carried out in RunzhouDistrict, Zhenjiang City, Jiangsu Province. The strategy was relied mainly on the Oncomelania hupensis snail control, extended chemotherapy of schistosomiasis in residents and the health education. The infection rate of schistosomiasis in residents, area with snails, area with snails controlled, and the rates of awareness and correct behavior of schistosomiasis were as evaluation indexes. RESULTS: The area with snails controlled was 7 091.50 hm2 in Runzhou District, Zhenjiang City from 2001 to 2016. The area with snails reduced year by year from 2001 to 2016. There was a negative correlation between the coverage intensity of snail control and the area with snails (r = -0.874, P = 0). There were 1 703 serum positive and 199 fecal positive people of schistosomiasis in the permanent residents from 2001 to 2016. These serum and fecal positive people of schistosomiasis were all treated with praziquantel. The serum positive rate of schistosomiasis in the permanent residents dropped to below 1.0% after 2005. The fecal positive patients were not found in 2004 and later. Totally 189 639 people received the questionnaire survey for the knowledge of schistosomiasis control from 2001 to 2016. The rates of awareness and correct behavior of schistosomiasis were raised in the residents year by year. The goal of the transmission interruption of schistosomiasis came to true in Runzhou District, Zhenjiang City in 2016. CONCLUSIONS: The comprehensive prevention and control strategy including mainly the snail control, extended chemotherapy of schistosomiasis and health education could achieve the goal of transmission interruption of schistosomiasis in the areas of marshland along the Yangtze River.

Diagnostic study on an immunochromatographic rapid test for schistosomiasis: comparison between use on serum and on blood spot from fingerprick.

BACKGROUND: An immunochromatographic rapid test (ICT; Schistosoma ICT IgG-IgM, LDBIO Diagnostics) demonstrated high sensitivity (96%) in the diagnosis of Schistosoma mansoni and S. haematobium. To date, the test has been validated for use on serum only, but in the absence of lab equipment, blood drop from fingerprick could be a useful option. This method is acquiring more interest because of the high flow of migrants rapidly moving across Italy and other European countries. OBJECTIVE: The aim of this prospective study was to evaluate the use of ICT on whole blood obtained from fingerprick. SETTING: Centre for Tropical Diseases (CTD), Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy. PARTICIPANTS: The inclusion criteria were African migrants aged ≥18 years with epidemiological risk of infection. The exclusion criteria were refusal to participate in the study and impossibility of execution of one of the two study methods, for any reason. Seventy of the 72 eligible patients completed the study, 79% of whom were male. INTERVENTIONS: The ICT was performed twice for each included patient: one on blood drop (by the research nurses, in the ward) and one on serum (by staff of CTD lab). The primary outcome was the concordance between the two methods, assessed by Cohen's kappa. RESULTS: Cohen's kappa was 0.45 (95% CI 27.0 to 63.6), indicating moderate agreement between the ICT on serum and the ICT on blood drop. Assuming the results on serum as reference standard for diagnosis, the sensitivity and specificity of ICT on blood drop were 55% (95% CI 40 to 69) and 93% (95% CI 79 to 98), respectively. CONCLUSIONS: The agreement between the two diagnostic methods is too low to support the alternative one. Implementation of the kit for using blood drop instead of the serum and/or further studies aimed to identify easy-to-use tests for schistosomiasis feasible outside referral centres for tropical diseases are needed.

The blood fluke Schistosoma mansoni cleaves the coagulation protein high molecular weight kininogen (HK) but does not generate the vasodilator bradykinin.

BACKGROUND: Schistosomes are blood dwelling parasitic worms that cause the debilitating disease schistosomiasis. Here we examined the influence of the parasites on their external environment by monitoring the impact of adult Schistosoma mansoni worms on the murine plasma proteome in vitro and, in particular, on how the worms affect the blood coagulation protein high molecular weight kininogen (HK). METHODS: Following the incubation of adult schistosomes in murine plasma, two-dimensional differential in-gel electrophoresis (2D-DIGE) was conducted to look for changes in the plasma proteome compared with control plasma. A major change to the blood protein kininogen (HK) was observed, and the interaction of Schistosoma mansoni parasite with this protein alone was then investigated by western blot analysis and activity assays. Finally, the generation of bradykinin from HK was monitored using a bradykinin detection kit. RESULTS: The most striking change to the plasma proteome concerned HK; while the full-length protein was more abundant in control plasma, carboxyl-terminal truncated forms were more abundant in plasma that contained schistosomes. Incubating parasites in buffer with pure HK followed by Western blot analysis confirmed that human HK is degraded by the worms. The resulting digestion pattern differed from that brought about by kallikrein, a host serine protease that normally acts on HK to release the vasodilator bradykinin. We found that live schistosomes, while digesting HK, do not generate bradykinin nor do they cleave a chromogenic kallikrein substrate. Since the cleavage of HK by the worms is not impeded by the serine protease inhibitor PMSF but is blocked by the cysteine protease inhibitor E64c, we hypothesize that schistosome tegumental cysteine proteases are responsible for HK cleavage. CONCLUSIONS: Since proteomic and biochemical studies have revealed that the schistosome tegument contains two cysteine proteases belonging to the calpain family (SmCalp1 and SmCalp2) we conclude that these are likely responsible for the HK cleavage reported here. Schistosome cleavage of HK should help impede blood clotting and inflammation around the worms in vivo and so promote their ease of movement within the vasculature of their hosts.

Rifaximin Reduces Markers of Inflammation and Bacterial 16S rRNA in Zambian Adults with Hepatosplenic Schistosomiasis: A Randomized Control Trial.

Cirrhosis is the dominant cause of portal hypertension globally but may be overshadowed by hepatosplenic schistosomiasis (HSS) in the tropics. In Zambia, schistosomiasis seroprevalence can reach 88% in endemic areas. Bacterial translocation (BT) drives portal hypertension in cirrhosis contributing to mortality but remains unexplored in HSS. Rifaximin, a non-absorbable antibiotic may reduce BT. We aimed to explore the influence of rifaximin on BT, inflammation, and fibrosis in HSS. In this phase II open-label trial (ISRCTN67590499), 186 patients with HSS in Zambia were evaluated and 85 were randomized to standard care with or without rifaximin for 42 days. Changes in markers of inflammation, BT, and fibrosis were the primary outcomes. BT was measured using plasma 16S rRNA, lipopolysaccharide-binding protein, and lipopolysaccharide, whereas hyaluronan was used to measure fibrosis. Tumor necrosis factor receptor 1 (TNFR1) and soluble cluster of differentiation 14 (sCD14) assessed inflammation. 16S rRNA reduced from baseline (median 146 copies/µL, interquartile range [IQR] 9, 537) to day 42 in the rifaximin group (median 63 copies/µL, IQR 12, 196), P < 0.01. The rise in sCD14 was lower (P < 0.01) in the rifaximin group (median rise 122 ng/mL, IQR-184, 783) than in the non-rifaximin group (median rise 832 ng/mL, IQR 530, 967). TNFR1 decreased (P < 0.01) in the rifaximin group (median -39 ng/mL IQR-306, 563) but increased in the non-rifaximin group (median 166 ng/mL, IQR 3, 337). Other markers remained unaffected. Rifaximin led to a reduction of inflammatory markers and bacterial 16S rRNA which may implicate BT in the inflammation in HSS.

Vesicle-based secretion in schistosomes: Analysis of protein and microRNA (miRNA) content of exosome-like vesicles derived from Schistosoma mansoni.

Exosomes are small vesicles of endocytic origin, which are released into the extracellular environment and mediate a variety of physiological and pathological conditions. Here we show that Schistosoma mansoni releases exosome-like vesicles in vitro. Vesicles were purified from culture medium by sucrose gradient fractionation and fractions containing vesicles verified by western blot analyses and electron microscopy. Proteomic analyses of exosomal contents unveiled 130 schistosome proteins. Among these proteins are common exosomal markers such as heat shock proteins, energy-generating enzymes, cytoskeletal proteins, and others. In addition, the schistosome extracellular vesicles contain proteins of potential importance for host-parasite interaction, notably peptidases, signaling proteins, cell adhesion proteins (e.g., integrins) and previously described vaccine candidates, including glutathione-S-transferase (GST), tetraspanin (TSP-2) and calpain. S. mansoni exosomes also contain 143 microRNAs (miRNA), of which 25 are present at high levels, including miRNAs detected in sera of infected hosts. Quantitative PCR analysis confirmed the presence of schistosome-derived miRNAs in exosomes purified from infected mouse sera. The results provide evidence of vesicle-mediated secretion in these parasites and suggest that schistosome-derived exosomes could play important roles in host-parasite interactions and could be a useful tool in the development of vaccines and therapeutics.

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).

The changing aetiology of eosinophilia in migrants and returning travellers in the Hospital for Tropical Diseases, London 2002-2015: An observational study.

INTRODUCTION: Determining the cause of eosinophilia in patients returning from the tropics continues to present a diagnostic challenge. The history, symptoms and degree of eosinophilia are often poor predictors of eventual diagnosis, but helminths are an important cause. The current British Infection Association recommendations use travel history to guide investigation of eosinophilia. However the global burden of helminth disease and travel patterns have changed over the last 3 decades and guidelines based on previous epidemiology need to be reviewed in the light of current data. METHODS: Consecutive patients presenting with, or referred for, investigation of eosinophilia were identified prospectively. Case notes, laboratory results and electronic records were reviewed for demographic and clinical data. Patients with an eosinophil count ≥0.50 × 109/L were included, and grouped based on lifetime history of travel to: West Africa, elsewhere in Africa, and the rest of the world. Results were compared to published data from 1997 to 2002 collected at the same centre. RESULTS: Of 410 patients who met the inclusion criteria, 407 had a documented travel history. Average yearly referrals for eosinophilia fell from 58 per year between 1997 and 2002, to 33 per year (2002-2015). The proportion of eosinophilia cases diagnosed with a parasitic cause fell from 64% to 50%, and yields for all parasitological investigations fell, the largest reduction in stool microscopy (20% yield to 9%) and day bloods for microfilariae (14% yield to 3%). Strongyloides stercoralis was the commonest diagnosis overall in our cohort, accounting for 50% of the total parasites diagnosed, and was present in 38% of patients from West Africa, 19% from rest of Africa, and 34% from rest of world; a relative increase compared to previous data. Schistosomiasis is slightly less common in those who had travelled to West Africa than the rest of Africa, and overall point prevalence has fallen from 33% (1997-2002) to 17% (2002-2015). Travellers were significantly less likely than patients who had immigrated to the UK to be diagnosed with any parasite (OR 0.54 95% CI 0.378-0.778 p = 0.0009). DISCUSSION: A parasitic cause will still be found in half of people returning from the tropics with an eosinophilia, but we observed a fall in the overall prevalence of parasitic diagnoses when compared with the earlier data. This may, in part, be explained by the impact of control programmes on the prevalence of parasites globally, especially filarial disease. S. stercoralis now represents the majority of parasites diagnosed in our cohort from all continents. We identified significantly higher rates of strongyloidiasis in immigrants than returning travellers. Despite the falling yields of stool microscopy and filarial serology the current guidelines based on travel history remain relevant with adequate yield.