Excretion patterns of Schistosoma mansoni antigens CCA and CAA by adult male and female worms, using a mouse model and ex vivo parasite cultures.

Assays which enable the detection of schistosome gut-associated circulating anodic (CAA) and cathodic (CCA) antigen in serum or urine are increasingly used as a diagnostic tool for schistosome infection. However, little is known about the production and clearance of these circulating antigens in relation to the sex and reproductive maturity of the parasite. Here we describe CAA and CCA excretion patterns by exploring a mouse model after exposure to 36 male-only, female-only and mixed (male/female) Schistosoma mansoni cercariae. We found that serum and urine CAA levels, analysed at 3 weeks intervals, peaked at 6 weeks post-infection. Worms recovered after perfusion at 14 weeks were cultured ex vivo. Male parasites excreted more circulating antigens than females, in the mouse model as well as ex vivo. In mixed infections (supporting egg production), serum CAA levels correlated to the number of recovered worms, whereas faecal egg counts or Schistosoma DNA in stool did not. No viable eggs and no inflammation were seen in the livers from mice infected with female worms only. Ex vivo, CAA levels were higher than CCA levels. Our study confirms that CAA levels reflect worm burden and allows detection of low-level single-sex infections.

The burden of HIV, syphilis and schistosome infection and associated factors among adults in the fishing communities in northwestern Tanzania.

OBJECTIVES: To quantify the burden of HIV, syphilis and schistosome infection and associated risk factors among adults living in seven fishing communities of Lake Victoria in northwest Tanzania. METHODS: Cross-sectional study conducted between 2015 and 2016 in the selected communities. In each community, we randomly selected a sample of adults from the general population and from three putative risk groups including the following: (i) fishermen, (ii) fish processors and traders, and (iii) women working in the recreational facilities. Participants were interviewed to obtain information about potential risk factors, and venous blood was collected for detection of HIV, syphilis and schistosome infections. We used logistic regression models to quantify the associations between potential risk factors and HIV, and also between schistosome infection and HIV. RESULTS: We enrolled 1128 people from selected fishing communities. The overall prevalence of HIV, syphilis and schistosome infection was 14.2%, 15.6% and 83.1%, respectively. Female recreational facility workers had the highest prevalence of HIV (30.4%) and syphilis (24%). The odds of being HIV infected were generally higher in all age categories. Transactional sex was commonly reported and especially receiving gifts for sex was found to be strongly associated with HIV (adjusted OR = 2.50; 95% CI: 1.44-4.34, P = 0.008). Confirmed serological syphilis was associated with increased odds of having HIV infection. HIV was not associated with schistosome infection in a combined dataset and when we examined this separately for men and women alone. CONCLUSIONS: We observed a high burden of HIV, syphilis and schistosome infections in the fishing communities. Targeted efforts to treat and control infections have the potential to improve health among their residents.

OBJECTIFS: Quantifier la charge du VIH, de la syphilis et de l'infection à schistosomes et les facteurs de risque associés chez les adultes vivant dans sept communautés de pêcheurs du lac Victoria dans le nord-ouest de la Tanzanie. MÉTHODES: Etude transversale menée entre 2015-2016 dans les communautés sélectionnées. Dans chaque communauté, nous avons sélectionné aléatoirement un échantillon d'adultes de la population générale et de trois groupes à risque présumés, notamment: 1) les pêcheurs, 2) les transformateurs et commerçants de poisson et 3) les femmes travaillant dans les établissements de loisirs. Les participants ont été interrogés pour obtenir des informations sur les facteurs de risque potentiels, et du sang veineux a été collecté pour la détection du VIH, de la syphilis et des infections à schistosome. Nous avons utilisé des modèles de régression logistique pour quantifier les associations entre les facteurs de risque potentiels et le VIH, ainsi qu'entre l'infection à schistosome et le VIH. RÉSULTATS: Nous avons recruté 1.128 personnes dans une sélection de communautés de pêcheurs. La prévalence globale de l'infection par le VIH, la syphilis et les schistosomes était de 14,2%, 15,6% et 83,1% respectivement. Les travailleuses des établissements de loisirs avaient la prévalence la plus élevée du VIH (30,4%) et de la syphilis (24%). Les chances d'être infecté par le VIH étaient généralement plus élevées dans toutes les catégories d'âge. Les rapports sexuels transactionnels étaient fréquemment rapportés et surtout le fait de recevoir des cadeaux pour le sexe était fortement associé au VIH (OR ajusté = 2,50; IC95%: 1,44-4,34 ; P = 0,008). La syphilis sérologique confirmée était associée à une probabilité accrue d'être infecté par le VIH. Le VIH n'était pas associé à une infection à schistosome dans un ensemble de données combinées et lorsque nous avons examiné cela séparément pour les hommes et les femmes. CONCLUSIONS: Nous avons observé une charge élevée d'infections par le VIH, la syphilis et les schistosomes dans les communautés de pêcheurs. Des efforts ciblés pour traiter et contrôler les infections ont le potentiel d'améliorer la santé des résidents.

Prospective, observational study to assess the performance of CAA measurement as a diagnostic tool for the detection of Schistosoma haematobium infections in pregnant women and their child in Lambaréné, Gabon: study protocol of the freeBILy clinical trial in Gabon.

BACKGROUND: Schistosoma antigen detection in urine is a valuable diagnostic approach for schistosomiasis control programmes because of the higher sensitivity compared to parasitological methods and preferred sampling of urine over stool. Highly accurate diagnostics are important in low Schistosoma transmission areas. Pregnant women and young children could particularly benefit from antigen testing as praziquantel (PZQ) can be given to only confirmed Schistosoma cases. This prevents the unborn baby from unnecessary exposure to PZQ. We present here the protocol of a diagnostic study that forms part of the freeBILy project. The aim is to evaluate the accuracy of circulating anodic antigen (CAA) detection for diagnosis of Schistosoma haematobium infections in pregnant women and to validate CAA as an endpoint measure for anti-Schistosoma drug efficacy. The study will also investigate Schistosoma infections in infants. METHODS: A set of three interlinked prospective, observational studies is conducted in Gabon. The upconverting phosphor lateral flow (UCP-LF) CAA test is the index diagnostic test that will be evaluated. The core trial, sub-study A, comprehensively evaluates the accuracy of the UCP-LF CAA urine test against a set of other Schistosoma diagnostics in a cross-sectional trial design. Women positive for S. haematobium will proceed with sub-study B and will be randomised to receive PZQ treatment immediately or after delivery followed by weekly sample collection. This approach includes comparative monitoring of CAA levels following PZQ intake and will also contribute further data for safety of PZQ administration during pregnancy. Sub-study C is a longitudinal study to determine the incidence of S. haematobium infection as well as the age for first infection in life-time. DISCUSSION: The freeBILy trial in Gabon will generate a comprehensive set of data on the accuracy of the UCP-LF CAA test for the detection of S. haematobium infection in pregnant women and newborn babies and for the use of CAA as a marker to determine PZQ efficacy. Furthermore, incidence of Schistosoma infection in infants will be reported. Using the ultrasensitive diagnostics, this information will be highly relevant for Schistosoma prevalence monitoring by national control programs as well as for the development of medicaments and vaccines. TRIAL REGISTRATION: The registration number of this study is NCT03779347 ( clinicaltrials.gov , date of registration: 19 December 2018).

Altered Cervical Mucosal Gene Expression and Lower Interleukin 15 Levels in Women With Schistosoma haematobium Infection but Not in Women With Schistosoma mansoni Infection.

BACKGROUND: Schistosomiasis increases the risk of human immunodeficiency virus (HIV) acquisition in women by mechanisms that are incompletely defined. Our objective was to determine how the cervical environment is impacted by Schistosoma haematobium or Schistosoma mansoni infection by quantifying gene expression in the cervical mucosa and cytokine levels in cervicovaginal lavage fluid. METHODS: We recruited women with and those without S. haematobium infection and women with and those without S. mansoni infection from separate villages in rural Tanzania with high prevalences of S. haematobium and S. mansoni, respectively. Infection status was determined by urine and stool microscopy and testing for serum circulating anodic antigen. RNA was extracted from cervical cytobrush samples for transcriptome analysis. Cytokine levels were measured by magnetic bead immunoassay. RESULTS: In the village where S. haematobium was prevalent, 110 genes were differentially expressed in the cervical mucosa of 18 women with versus 39 without S. haematobium infection. Among the 27 cytokines analyzed in cervicovaginal lavage fluid from women in this village, the level of interleukin 15 was lower in the S. haematobium-infected group (62.8 vs 102.9 pg/mL; adjusted P = .0013). Differences were not observed in the S. mansoni-prevalent villages between 11 women with and 29 without S. mansoni infection. CONCLUSIONS: We demonstrate altered cervical mucosal gene expression and lower interleukin 15 levels in women with S. haematobium infection as compared to those with S. mansoni infection, which may influence HIV acquisition and cancer risks. Studies to determine the effects of antischistosome treatment on these mucosal alterations are needed.

Gene Expression Differences in Host Response to Schistosoma haematobium Infection.

Schistosome worms infect over 200 million people worldwide. They live in the host's bloodstream and alter host immunity. Epidemiological data suggest that males and females have different responses to schistosome infection, but the effect of sex on systemic response is undetermined. Our objective was to characterize differences in peripheral blood transcriptional profiles in people with or without active Schistosoma haematobium infection and to determine whether this signature differs between males and females. mRNA was isolated using poly(A) selection and sequenced on an Illumina Hi-Seq4000 platform. Transcripts were aligned to the human hg19 reference genome and counted with the HTSeq package. Genes were compared for differential expression using DESeq2. Ingenuity Pathway Analysis (IPA) was used to identify gene networks altered in the presence of S. haematobium We enrolled 33 participants from villages in rural Tanzania where S. haematobium is endemic. After correction for multiple comparisons, we observed 383 differentially expressed genes between those with or without S. haematobium infection when sex was included as a covariate. Heat-mapping of the genes with >1.5-fold differences in gene expression revealed clustering by S. haematobium infection status. The top networks included development, cell death and survival, cell signaling, and immunologic disease pathways. We observed a distinct whole blood transcriptional profile, as well as differences in men and women, with S. haematobium infection. Additional studies are needed to determine the clinical effects of these divergent responses. Attention to sex-based differences should be included in studies of human schistosome infection.

Schistosomiasis and HIV-1 viral load in HIV-infected outpatients with immunological failure in Tanzania: a case-control study.

BACKGROUND: Schistosoma sp. infection has been shown to interact with HIV-1 by modifying susceptibility to the virus and impacting AIDS outcome, but very little is known about the potential impact of Schistosoma sp. infection on the efficiency of antiretroviral treatment (ART) in HIV-1 infected individuals. One study suggested increased immunological failure in patients infected with schistosomes compared to those uninfected. To our knowledge, no report exists on the virological response to ART in schistosome-infected individuals. In addition, viral load in HIV-1 infected individuals changes over the course of the HIV infection. This study assessed the impact of HIV-1/Schistosoma sp. co-infections on viral load in people with immunological failure on ART, taking into account the duration of HIV-1 infection. METHODS: We enrolled HIV-1 infected Tanzanian adults over 18 years of age who had used first line ART for more than 6 months and were identified to have immunological failure by the WHO criteria (50% drop from peak CD4 count, or CD4 count equal to or below baseline after 6 months of ART, or CD4 count below 100cells/mm3 after 1 year of ART). Patients were also tested for schistosome infection by microscopy for ova in urine and stool and by circulating anodic antigen (CAA) levels in serum. The duration of HIV-1 infection was calculated using baseline CD4+ T-cell (CD4) counts determined at enrollment. Univariable and multivariable analyses were conducted to compare viral loads in schistosome infected and uninfected patients. RESULTS: A total of 188 patients were enrolled. After univariable analysis, female sex, lower peak CD4 counts, lower current CD4 counts, anemia, and shorter time infected with HIV-1 were all significantly associated with higher viral load. Schistosome infection was not associated with viral load even after adjusting for sex, current CD4 counts and duration of HIV-1 infection. CONCLUSIONS: The current study of HIV-infected patients with immunological failure on ART suggests that once ART is introduced, ART is the dominant driver of viral load and schistosome infection may no longer have an impact.

HIV-seroconversion among HIV-1 serodiscordant married couples in Tanzania: a cohort study.

BACKGROUND: Heterosexual transmission is the main driver of the HIV epidemic in Tanzania. Only one estimate of the incidence rate of intra-marital HIV seroconversion in Tanzania has been reported and was derived from data collected between 1991 and 1995. Moreover, little is known about the specific risk factors for intra-marital seroconversion in Tanzania. Improved evidence around factors that increase the risk of HIV transmission to a serodiscordant spouse is needed to develop and improve evidence-based interventions. We sought to investigate the rate of intra-marital HIV seroconversion among HIV sero-discordant couples in Tanzania as well as its associated risk factors. METHODS: We identified all HIV positive individuals in the TAZAMA HIV-serosurvey cohort and followed up their serodiscordant spouse from 2006 to 2016. The rate of seroconversion was analyzed by survival analysis using non-parametric regressions with exponential distribution. RESULTS: We found 105 serodiscordant couples, 14 of which had a seroconverting spouse. The overall HIV-1 incidence rate among spouses of people with HIV-1 infection was 38.0 per 1000 person/years [22.5-64.1]. Notably, the HIV-1 incidence rate among HIV-1 seronegative male spouses was 6.7[0.9-47.5] per 1000 person/years, compared to 59.3 [34.4-102.1] per 1000 person/years among female spouses. Sex of the serodiscordant spouse was the only significant variable, even after adjusting for other variables (Hazard rate = 8.86[1.16-67.70], p = 0.036). CONCLUSIONS: Our study suggests that rates of HIV-1 seroconversion of sero-discordant partners are much higher within marriage than in the general population in Tanzania. The major risk factor for HIV-1 seroconversion is sex of the serodiscordant spouse, with female spouses being at very high risk of acquiring HIV infection. This suggests that future programs that target serodiscordant couples could be a novel and effective means of preventing HIV-1 transmission in Tanzania.

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.

Poly(amidoamine)-coated magnetic particles for enhanced detection of Schistosoma circulating anodic antigen in endemic urine samples.

Accurate and sensitive point-of-care diagnostic tools are critical for schistosomiasis control and elimination. The existing ultrasensitive lateral flow assay for the detection of Schistosoma circulating anodic antigen (CAA) has demonstrated excellent sensitivity but is time-consuming and requires significant laboratory infrastructure that limits its applicability at the point of care. To address this challenge, we sought to develop an alternative sample preparation method to concentrate CAA from large-volume urine samples requiring little-to-no laboratory equipment. The developed method relies on electrostatic interactions between the negatively-charged CAA biomarker and positively-charged poly(amidoamine) (PAMAM) dendrimers functionalized to the surface of magnetic particles. After CAA capture on the surface of the PAMAM-functionalized magnetic beads, the supernatant was removed, and CAA was eluted into a small-volume, high-salt elution buffer. This concentrated eluate was subsequently applied to the existing lateral flow assay. The PAMAM-functionalized magnetic bead-based CAA concentration method was extensively characterized for its robustness, evaluated on a set of endemic urine samples, and compared to spin filter-based concentration methods. The novel bead-based sample preparation method used only disposable laboratory materials, resulted in a 200-fold improvement in CAA limits of detection, and performed just as well as infrastructure-intensive and high-cost spin filter methods. Additionally, the functionalized beads were robust to variations in sample pH and storage conditions. The PAMAM-functionalized magnetic bead-based CAA concentration method represents a promising step toward ultrasensitive schistosomiasis diagnosis at the point of care.

Schistosoma mansoni and HIV acquisition in fishing communities of Lake Victoria, Uganda: a nested case-control study.

OBJECTIVE: It has been suggested that Schistosoma mansoni, which is endemic in African fishing communities, might increase susceptibility to human immunodeficiency virus (HIV) acquisition. If confirmed, this would be of great public health importance in these high HIV-risk communities. This study was undertaken to determine whether S. mansoni infection is a risk factor for HIV infection among the fishing communities of Lake Victoria, Uganda. We conducted a matched case-control study, nested within a prospective HIV incidence cohort, including 50 HIV seroconverters (cases) and 150 controls during 2009-2011. METHODS: S. mansoni infection prior to HIV seroconversion was determined by measuring serum circulating anodic antigen (CAA) in stored serum. HIV testing was carried out using the Determine rapid test and infection confirmed by enzyme-linked immunosorbent assays. RESULTS: About 49% of cases and 52% of controls had S. mansoni infection prior to HIV seroconversion (or at the time of a similar study visit, for controls): odds ratio, adjusting for ethnicity, religion, marital status, education, occupation, frequency of alcohol consumption in previous 3 months, number of sexual partners while drunk, duration of stay in the community, and history of schistosomiasis treatment in the past 2 years was 1.23 (95% CI 0.3-5.7) P = 0.79. S. mansoni infections were chronic (with little change in status between enrolment and HIV seroconversion), and there was no difference in median CAA concentration between cases and controls. CONCLUSIONS: These results do not support the hypothesis that S. mansoni infection promotes HIV acquisition.

Human Schistosoma haematobium antifecundity immunity is dependent on transmission intensity and associated with immunoglobulin G1 to worm-derived antigens.

BACKGROUND: Immunity that reduces worm fecundity and, in turn, reduces morbidity is proposed for Schistosoma haematobium, a parasite of major public health importance. Mathematical models of epidemiological trends suggest that antifecundity immunity is dependent on antibody responses to adult-worm-derived antigen. METHODS: For a Malian cohort (age, 5-29 years) residing in high-transmission fishing villages or a moderate-transmission village, worm fecundity was assessed using the ratio of urinary egg excretion to levels of circulating anodic antigen, a Schistosoma-specific antigen that is steadily secreted by adult worms. Fecundity was modeled against host age, infection transmission intensity, and antibody responses specific to soluble worm antigen (SWA), tegument allergen-like 1, and 28-kDa glutathione-S-transferase. RESULTS: Worm fecundity declined steadily until a host age of 11 years. Among children, host age and transmission were negatively associated with worm fecundity. A significant interaction term between host age and transmission indicates that antifecundity immunity develops earlier in high-transmission areas. SWA immunoglobulin G1 (IgG1) levels explained the effect of transmission on antifecundity immunity. CONCLUSION: Antifecundity immunity, which is likely to be protective against severe morbidity, develops rapidly during childhood. Antifecundity immunity is associated with SWA-IgG1, with higher infection transmission increasing this response at an earlier age, leading to earlier development of antifecundity immunity.

A latent Markov modelling approach to the evaluation of circulating cathodic antigen strips for schistosomiasis diagnosis pre- and post-praziquantel treatment in Uganda.

Regular treatment with praziquantel (PZQ) is the strategy for human schistosomiasis control aiming to prevent morbidity in later life. With the recent resolution on schistosomiasis elimination by the 65th World Health Assembly, appropriate diagnostic tools to inform interventions are keys to their success. We present a discrete Markov chains modelling framework that deals with the longitudinal study design and the measurement error in the diagnostic methods under study. A longitudinal detailed dataset from Uganda, in which one or two doses of PZQ treatment were provided, was analyzed through Latent Markov Models (LMMs). The aim was to evaluate the diagnostic accuracy of Circulating Cathodic Antigen (CCA) and of double Kato-Katz (KK) faecal slides over three consecutive days for Schistosoma mansoni infection simultaneously by age group at baseline and at two follow-up times post treatment. Diagnostic test sensitivities and specificities and the true underlying infection prevalence over time as well as the probabilities of transitions between infected and uninfected states are provided. The estimated transition probability matrices provide parsimonious yet important insights into the re-infection and cure rates in the two age groups. We show that the CCA diagnostic performance remained constant after PZQ treatment and that this test was overall more sensitive but less specific than single-day double KK for the diagnosis of S. mansoni infection. The probability of clearing infection from baseline to 9 weeks was higher among those who received two PZQ doses compared to one PZQ dose for both age groups, with much higher re-infection rates among children compared to adolescents and adults. We recommend LMMs as a useful methodology for monitoring and evaluation and treatment decision research as well as CCA for mapping surveys of S. mansoni infection, although additional diagnostic tools should be incorporated in schistosomiasis elimination programs.

Diagnostics for schistosomiasis in Africa and Arabia: a review of present options in control and future needs for elimination.

Within the World Health Organization 2012-2020 roadmap for control and elimination of schistosomiasis, the scale-up of mass drug administration with praziquantel is set to change the epidemiological landscape across Africa and Arabia. Central in measuring progress is renewed emphasis upon diagnostics which operate at individual, community and environmental levels by assessing reductions in disease, infections and parasite transmission. However, a fundamental tension is revealed between levels for present diagnostic tools, and methods applied in control settings are not necessarily adequate for application in elimination scenarios. Indeed navigating the transition from control to elimination needs careful consideration and planning. In the present context of control, we review current options for diagnosis of schistosomiasis at different levels, highlighting several strengths and weaknesses therein. Future challenges in elimination are raised and we propose that more cost-effective diagnostics and clinical staging algorithms are needed. Using the Kingdom of Saudi Arabia as a contemporary example, embedding new diagnostic methods within the primary care health system is discussed with reference to both urogenital and intestinal schistosomiasis.

Tools for diagnosis, monitoring and screening of Schistosoma infections utilizing lateral-flow based assays and upconverting phosphor labels.

The potential of various quantitative lateral flow (LF) based assays utilizing up-converting phosphor (UCP) reporters for the diagnosis of schistosomiasis is reviewed including recent developments. Active infections are demonstrated by screening for the presence of regurgitated worm antigens (genus specific polysaccharides), whereas anti-Schistosoma antibodies may indicate ongoing as well as past infections. The circulating anodic antigen (CAA) in serum or urine (and potentially also saliva) is identified as the marker that may allow detection of single-worm infections. Quantitation of antigen levels is a reliable method to study effects of drug administration, worm burden and anti-fecundity mechanisms. Moreover, the ratio of CAA and circulating cathodic antigen (CCA) is postulated to facilitate identification of either Schistosoma mansoni or Schistosoma haematobium infections. The UCP-LF assays allow simultaneous detection of multiple targets on a single strip, a valuable feature for antibody detection assays. Although antibody detection in endemic regions is not a useful tool to diagnose active infections, it gains potential when the ratio of different classes of antibody specific for the parasite/disease can be determined. The UCP-LF antibody assay format allows this type of multiplexing, including testing a linear array of up to 20 different targets. Multiple test spots would allow detection of specific antibodies, e.g. against different Schistosoma species or other pathogens as soil-transmitted helminths. Concluding, the different UCP-LF based assays for diagnosis of schistosomiasis provide a collection of tests with relatively low complexity and high sensitivity, covering the full range of diagnostics needed in control programmes for mapping, screening and monitoring.

Flow-S: A Field-Deployable Device with Minimal Hands-On Effort to Concentrate and Quantify Schistosoma Circulating Anodic Antigen (CAA) from Large Urine Volumes.

A laboratory-based lateral flow (LF) test that utilizes up-converting reporter particles (UCP) for ultrasensitive quantification of Schistosoma circulating anodic antigen (CAA) in urine is a well-accepted test to identify active infection. However, this UCP-LF CAA test requires sample pre-treatment steps not compatible with field applications. Flow, a new low-cost disposable, allows integration of large-volume pre-concentration of urine analytes and LF detection into a single field-deployable device. We assessed a prototype Flow-Schistosoma (Flow-S) device with an integrated UCP-LF CAA test strip, omitting all laboratory-based steps, to enable diagnosis of active Schistosoma infection in the field using urine. Flow-S is designed for large-volume (5-20 mL) urine, applying passive paper-based filtration and antibody-based CAA concentration. Samples tested for schistosome infection were collected from women of reproductive age living in a Tanzania region where S. haematobium infection is endemic. Fifteen negative and fifteen positive urine samples, selected based on CAA levels quantified in paired serum, were analyzed with the prototype Flow-S. The current Flow-S prototype, with an analytical lower detection limit of 1 pg CAA/mL, produced results correlated with the laboratory-based UCP-LF CAA test. Urine precipitates occurred in frozen banked samples and affected accurate quantification; however, this should not occur in fresh urine. Based on the findings of this study, Flow-S appears suitable to replace the urine pre-treatment required for the laboratory-based UCP-LF CAA test, thus allowing true field-based applications with fresh urine samples. The urine precipitates observed with frozen samples, though less important given the goal of testing fresh urines, warrant additional investigation to evaluate methods for mitigation. Flow-S devices permit testing of pooled urine samples with applications for population stratified testing. A field test with fresh urine samples, a further optimized Flow-S device, and larger statistical power has been scheduled.

Clinical and Demographic Factors Associated With Kaposi Sarcoma-Associated Herpesvirus Shedding in Saliva or Cervical Secretions in a Cohort of Tanzanian Women.

Background: Reasons for the high prevalence of Kaposi sarcoma-associated herpesvirus (KSHV) in sub-Saharan Africa, and risk factors leading to viral reactivation and shedding, remain largely undefined. Preliminary studies have suggested that schistosome infection, which has been associated with impaired viral control, is associated with KSHV. In this study we sought to determine the relationship between active Schistosoma mansoni or Schistosoma haematobium infection and KSHV shedding. Methods: We quantified KSHV DNA in saliva and cervical swabs from 2 cohorts of women living in northwestern Tanzanian communities endemic for S mansoni or S haematobium by real-time polymerase chain reaction. χ2 and Fisher exact tests were used to determine differences in clinical and demographic factors between those who were and were not shedding KSHV. Results: Among 139 total women, 44.6% were KSHV seropositive. Six percent of those with S mansoni and 17.1% of those with S haematobium were actively shedding KSHV in saliva and none in cervical samples. Women from the S mansoni cohort who were shedding virus reported infertility more frequently (80% vs 19.5%, P = .009). There was no difference in frequency of KSHV salivary shedding between schistosome-infected and -uninfected women. Conclusions: In an area with high KSHV seroprevalence and endemic schistosome infections, we provide the first report with data demonstrating no association between schistosome infection and salivary or cervical herpesvirus shedding. KSHV salivary shedding was associated with infertility, a known effect of another herpesvirus, human herpesvirus 6.

Schistosome infection among pregnant women in the rural highlands of Madagascar: A cross-sectional study calling for public health interventions in vulnerable populations.

INTRODUCTION: Schistosomiasis is a parasitic infection highly prevalent in sub-Saharan Africa (SSA) with Madagascar being among the countries with highest burden of the disease worldwide. Despite WHO recommendations, suggesting treatment of pregnant women after the first trimester, this group is still excluded from Mass Drug Administration programs. Our study, had the objective to measure the prevalence of schistosome infection among pregnant women in Madagascar in order to inform public health policies for treatment in this vulnerable population. METHODS: Women were recruited for this cross-sectional study between April 2019 and February 2020 when attending Antenatal Care Services (ANCs) at one of 42 included Primary Health Care Centers. The urine-based upconverting reporter particle, lateral flow (UCP-LF) test detecting circulating anodic antigen was used for the detection of schistosome infections. To identify factors associated with the prevalence of schistosome infection crude and adjusted prevalence ratios and 95% CIs were estimated using mixed-effect Poisson regression. RESULTS: Among 4,448 participating women aged between 16 and 47 years, the majority (70.4%, 38 n = 3,133) resided in rural settings. Overall, the prevalence of schistosome infection was 55.9% (n = 2486, CI 95%: 53.3-58.5). A statistically significant association was found with age group (increased prevalence in 31-47 years old, compared to 16-20 years old (aPR = 1.15, CI 95%: 1.02-1.29) and with uptake of antimalaria preventive treatment (decreased prevalence, aPR = 0.85, CI 95%: 0.77-0.95). No other associations of any personal characteristics or contextual factors with schistosome infection were found in our multivariate regression analysis. DISCUSSION AND CONCLUSION: The high prevalence of schistosome infection in pregnant women supports the consideration of preventive schistosomiasis treatment in ANCs of the Malagasy highlands. We strongly advocate for adapting schistosomiasis programs in highly endemic contexts. This, would contribute to both the WHO and SDGs agendas overall to improving the well-being of women and consequently breaking the vicious cycle of poverty perpetuated by schistosomiasis.

A robust dry reagent lateral flow assay for diagnosis of active schistosomiasis by detection of Schistosoma circulating anodic antigen.

UNLABELLED: An earlier reported laboratory assay, performed in The Netherlands, to diagnose Schistosoma infections by detection of the parasite antigen CAA in serum was converted to a more user-friendly format with dry reagents. The improved assay requires less equipment and allows storage and worldwide shipping at ambient temperature. Evaluation of the new assay format was carried out by local staff at Ampath Laboratories, South Africa. The lateral flow (LF) based assay utilized fluorescent ultrasensitive up-converting phosphor (UCP) reporter particles, to be read by a portable reader (UPlink) that was also provided to the laboratory. Over a period of 18 months, about 2000 clinical samples were analyzed prospectively in parallel with a routinely carried out CAA-ELISA. LF test results and ELISA data correlated very well at CAA concentrations above 300 pg/mL serum. At lower concentrations the UCP-LF test indicates a better performance than the ELISA. The UCP-LF strips can be stored as a permanent record as the UCP label does not fade. At the end of the 18 months testing period, LF strips were shipped back to The Netherlands where scan results obtained in South Africa were validated with different UCP scanning equipment including a novel, custom developed, small lightweight UCP strip reader (UCP-Quant), well suited for testing in low resource settings. CONCLUSION: The dry format UCP-LF assay was shown to provide a robust and easy to use format for rapid testing of CAA antigen in serum. It performed at least as good as the ELISA with respect to sensitivity and specificity, and was found to be superior with respect to speed and simplicity of use. Worldwide shipping at ambient temperature of the assay reagents, and the availability of small scanners to analyze the CAA UCP-LF strip, are two major steps towards point-of-care (POC) applications in remote and resource poor environments to accurately identify low (30 pg CAA/mL serum; equivalent to about 10 worm pairs) to heavy Schistosoma infections.

Reproducibility matters: intra- and inter-sample variation of the point-of-care circulating cathodic antigen test in two Schistosoma mansoni endemic areas in Uganda.

Over 240 million people are infected with schistosomiasis. Detecting Schistosoma mansoni eggs in stool using Kato-Katz thick smears (Kato-Katzs) is highly specific but lacks sensitivity. The urine-based point-of-care circulating cathodic antigen test (POC-CCA) has higher sensitivity, but issues include specificity, discrepancy between batches and interpretation of trace results. A semi-quantitative G-score and latent class analyses making no assumptions about trace readings have helped address some of these issues. However, intra-sample and inter-sample variation remains unknown for POC-CCAs. We collected 3 days of stool and urine from 349 and 621 participants, from high- and moderate-endemicity areas, respectively. We performed duplicate Kato-Katzs and one POC-CCA per sample. In the high-endemicity community, we also performed three POC-CCA technical replicates on one urine sample per participant. Latent class analysis was performed to estimate the relative contribution of intra- (test technical reproducibility) and inter-sample (day-to-day) variation on sensitivity and specificity. Within-sample variation for Kato-Katzs was higher than between-sample, with the opposite true for POC-CCAs. A POC-CCA G3 threshold most accurately assesses individual infections. However, to reach the WHO target product profile of the required 95% specificity for prevalence and monitoring and evaluation, a threshold of G4 is needed, but at the cost of reducing sensitivity. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.

Sensitivity and specificity of human point-of-care circulating cathodic antigen (POC-CCA) test in African livestock for rapid diagnosis of schistosomiasis: A Bayesian latent class analysis.

Schistosomiasis is a major neglected tropical disease (NTD) affecting both humans and animals. The morbidity and mortality inflicted upon livestock in the Afrotropical region has been largely overlooked, in part due to a lack of validated sensitive and specific tests, which do not require specialist training or equipment to deliver and interpret. As stressed within the recent WHO NTD 2021-2030 Roadmap and Revised Guideline for schistosomiasis, inexpensive, non-invasive, and sensitive diagnostic tests for livestock-use would also facilitate both prevalence mapping and appropriate intervention programmes. The aim of this study was to assess the sensitivity and specificity of the currently available point-of-care circulating cathodic antigen test (POC-CCA), designed for Schistosoma mansoni detection in humans, for the detection of intestinal livestock schistosomiasis caused by Schistosoma bovis and Schistosoma curassoni. POC-CCA, together with the circulating anodic antigen (CAA) test, miracidial hatching technique (MHT), Kato-Katz (KK) and organ and mesentery inspection (for animals from abattoirs only), were applied to samples collected from 195 animals (56 cattle and 139 small ruminants (goats and sheep) from abattoirs and living populations) from Senegal. POC-CCA sensitivity was greater in the S. curassoni-dominated Barkedji livestock, both for cattle (median 81%; 95% credible interval (CrI): 55%-98%) and small ruminants (49%; CrI: 29%-87%), than in the S. bovis-dominated Richard Toll ruminants (cattle: 62%; CrI: 41%-84%; small ruminants: 12%, CrI: 1%-37%). Overall, sensitivity was greater in cattle than in small ruminants. Small ruminants POC-CCA specificity was similar in both locations (91%; CrI: 77%-99%), whilst cattle POC-CCA specificity could not be assessed owing to the low number of uninfected cattle surveyed. Our results indicate that, whilst the current POC-CCA does represent a potential diagnostic tool for cattle and possibly for predominantly S. curassoni-infected livestock, future work is needed to develop parasite- and/or livestock-specific affordable and field-applicable diagnostic tests to enable determination of the true extent of livestock schistosomiasis.