[Schistosomiasis in areas of low endemicity: an overly neglected disease. The example of Schistosoma monsoni in BrazilEsquistossomose em áreas de baixa endemicidade, uma doença muito negligenciada. O exemplo de Schistosoma mansoni no Brasil]. / La schistosomose dans les zones de faible endémicité, une maladie trop négligée. Le cas de Schistosoma monsoni au Brésil.

Human schistosomiasis is a parasitic disease caused by an infection with trematodes of the genus Schistosoma. The disease mainly affects impoverished populations. Around 800 million people are exposed to the infection, which is a public health problem in the tropical and subtropical regions of Africa, Asia, the Caribbean and South America. In Brazil, Schistosoma mansoni is the only species that causes schistosomiasis and the disease is widely distributed. Conventional diagnosis of the disease is carried out by detecting eggs using parasitological methods, such as the Kato-Katz test. Schistosomiasis has been reported in all regions of Brazil and is characterized as endemic in seven states in the Northeast Region and two states in the Southeast Region. In 2015, 78,7% of all cases reported in Brazil occurred in the Northeast Region. It is estimated that 1,5 million people is infected with this disease in Brazil and more than 25 millions live in areas with a high risk of transmission. Despite the reduction in mortality and morbidity, schistosomiasis was responsible for 8,756 deaths between 2000 and 2011 and 2,517 deaths between 2015 and 2019 in Brazil and it remains an important public health problem. In the state of Rio de Janeiro, some areas have low endemicity or isolated foci of Schistosoma mansoni and the majority of infected individuals have mild infections. The last survey of the disease in the state of Rio de Janeiro was carried out between 2010 and 2015 in students aged 7 to 17.Schistosomiasis was reported in 10 of the 21 municipalities studied. Of the 5,111 school children screened for S. mansoni infection, 46 (1,65%) were tested positive. Studies carried out in areas of low endemicity in Rio de Janeiro showed that among the 205 patients infected by S. mansoni in Sumidouro, around 84% were aged 14 or over and all, except one individual, had the intestinal form (91,2%) or hepato-intestinal (8,3%) of schistosomiasis. Another study carried out in Sumidouro showed that with tests based on patent Schistosoma egg infection determined by the Kato-Katz test, active infections were diagnosed in eight (8/108) individuals. The intensity of infection expressed by parasite loads ranged from 6 to 72 eggs per gram of feces/individual. The results showed DNA amplification in 32 of the 100 individuals tested by real-time PCR. All individuals with patent ovo infection showed positive DNA amplification. These studies showed that if we only analyzed school-age children using the Kato-Katz test, the majority of the infected population would never be diagnosed with S. mansoni infection. In situations of low endemicity, with low intensities of infection, with low severity in the population and in the most affected age groups, schistosomiasis requires a more sensitive diagnostic approach (e.g. screening by PCR rather than Kato test), otherwise many infected individuals will remain invisible to the healthcare system.

A esquistossomose humana é uma doença parasitária causada por uma infecçâo por vermes sanguíneos do gènero Schistosoma. A doença afeta principalmente populaçoes empobrecidas. Cerca de 800 milhoes de pessoas estâo expostas à infecçâo, sendo um problema de saúde pública nas regioes tropicais e subtropicais de África, Ásia, Caribe e América do Sul. No Brasil, o Schistosoma mansoni é a única espécie causadora da esquistossomose e a doença é amplamente distribuida. O diagnóstico convencional da doença é realizado pela detecçâo dos ovos através de métodos parasitológicos, como o teste de Kato-Katz. A esquistossomose foi notificada em todas as regioes do Brasil, e é caracterizada como endèmica em sete estados da Regiâo Nordeste e dois estados da Regiâo Sudeste. Em 2015, 78,7% de todos os casos notificados no Brasil ocorreram na Regiâo Nordeste. Estima-se que 1,5 milhâo de pessoas estejam infectadas com esta doença no Brasil e mais de 25 milhoes vivam em áreas com alto risco de transmissâo. Apesar da reduçâo da mortalidade e morbidade, a esquistossomose foi relatada em 8.756 mortes entre 2000 e 2011 e em 2.517 mortes entre 2015 e 2019 no Brasil e continua sendo um importante problema de saúde pública. No Estado do Rio de Janeiro, algumas áreas apresentam baixa endemicidade ou focos isolados de Schistosoma mansoni e a maioria dos individuos infectados apresenta infecçoes leves. O último levantamento da doença no Estado do Rio de Janeiro foi realizado entre 2010 e 2015 em estudantes de 7 a 17 anos. A esquistossomose foi relatada em 10 dos 21 municipios estudados. Das 5.111 crianças escolares triadas para infecçâo por S. mansoni, 46 (1,65%) testaram positivo. Estudos realizados em áreas de baixa endemicidade no Rio de Janeiro mostraram que dentre os 205 pacientes infectados por S. mansoni em Sumidouro, cerca de 84% tinham 14 anos ou mais e todos, exceto um individuo, tinham a forma intestinal (91,2%) ou hepato-intestinal (8,3%) da esquistossomose. Outro estudo realizado em Sumidouro, mostrou que testes baseados em infecçâo patente de ovo de Schistosoma determinada pelo teste de Kato-Katz, infecçoes ativas foram diagnosticadas em oito (8/108) individuos. A intensidade de infecçâo expressa pelas cargas parasitárias variou de 6 a 72 ovos por grama de fezes/individuo. Os resultados mostraram amplificaçâo do DNA em 32 dos 100 individuos testados por PCR em tempo real. Todos os indivíduos com infecçâo ovo-patente apresentaram amplificaçâo de DNA positiva. Tais estudos mostraram que se analisarmos apenas crianças em idade escolar pelo teste de Kato-Katz, a maioria da populaçâo infectada nunca seria diagnosticada com infecçâo pelo S. mansoni. Em situaçoes de baixa endemicidade, com baixas intensidades de infecçâo, com baixa gravidade na populaçâo e nas faixas etárias mais afetadas, a esquistossomose requer uma abordagem diagnóstica mais sensivel (por exemplo, triagem por PCR em vez do teste de Kato), caso contràrio, muitos individuos infectados permanecerâo invisiveis para o sistema de saúde.

Rapid appraisal of liver diseases using transient elastography, abdominal ultrasound, and microbiology in Côte d'Ivoire: A single-center study.

BACKGROUND: Liver diseases of infectious and non-infectious etiology cause considerable morbidity and mortality, particularly in low- and middle-income countries (LMICs). However, data on the prevalence of liver diseases and underlying risk factors in LMICs are scarce. The objective of this study was to elucidate the occurrence of infectious diseases among individuals with chronic liver damage in a rural setting of Côte d'Ivoire. METHODOLOGY: In 2021, we screened 696 individuals from four villages in the southern part of Côte d'Ivoire for hepatic fibrosis and steatosis, employing transient elastography (TE) and controlled attenuation parameter (CAP). We classified CAP ≥248 dB/m as steatosis, TE ≥7.2 kPa as fibrosis, and did subgroup analysis for participants with TE ranging from 7.2 kPa to 9.1 kPa. Clinical and microbiologic characteristics were compared to an age- and sex-matched control group (TE <6.0 kPa; n = 109). Stool samples were subjected to duplicate Kato-Katz thick smears for diagnosis of Schistosoma mansoni. Venous blood samples were examined for hepatitis B and hepatitis C virus. Additionally, an abdominal ultrasound examination was performed. PRINCIPAL FINDINGS: Among 684 individuals with valid TE measurements, TE screening identified hepatic pathologies in 149 participants (17% with fibrosis and 6% with steatosis). 419 participants were included for further analyses, of which 261 had complete microbiologic analyses available. The prevalence of S. mansoni, hepatitis B, and hepatitis C were 30%, 14%, and 7%, respectively. Logistic regression analysis revealed higher odds for having TE results between 7.2 kPa and 9.1 kPa in individuals with S. mansoni infection (odds ratio [OR] = 3.02, 95% confidence interval [CI] = 1.58-5.76, P = 0.001), while HCV infection (OR = 5.02, 95% CI = 1.72-14.69, P = 0.003) and steatosis (OR = 4.62, 95% CI = 1.60-13.35, P = 0.005) were found to be risk factors for TE ≥9.2 kPa. CONCLUSIONS/SIGNIFICANCE: Besides viral hepatitis, S. mansoni also warrants consideration as a pathogen causing liver fibrosis in Côte d'Ivoire. In-depth diagnostic work-up among individuals with abnormal TE findings might be a cost-effective public health strategy.

Rapid and Comprehensive Screening for Urogenital and Gastrointestinal Schistosomiasis with Handheld Digital Microscopy Combined with Circulating Cathodic Antigen Testing.

Novel methods are required to aid the monitoring of schistosomiasis control and elimination initiatives through mass drug administration. Portable digital and mobile phone microscopy is a promising tool for this purpose. This cross-sectional study evaluated the diagnostic operating characteristics of a converted mobile phone microscope (the SchistoScope) for the detection of Schistosoma haematobium eggs, as determined by community-based field workers and expert microscopists, compared with a field gold standard of light microscopy. Three hundred sixty-five urine samples were evaluated by conventional light microscopy, with 49 (13.4%) positive for S. haematobium. Compared with light microscopy, the sensitivity and specificity of S. haematobium detection by field microscopists trained to use the SchistoScope were 26.5% (95% CI: 14.9-41.1%) and 98.4% (95% CI: 96.3-99.5%), respectively. The sensitivity and specificity of S. haematobium detection by expert microscopists using the SchistoScope was 74% (95% CI: 59.7-85.4%) and 98.1% (95% CI: 95.9-99.3%), respectively, compared with light microscopy. The sensitivity rose to 96.1% and 100% when evaluating for egg counts greater than five and 10 eggs per 10 mL, respectively. A point-of-care circulating cathodic anion (POC CCA) test was used to evaluate Schistosoma mansoni; however, there were too few positive samples to reliably comment on diagnostic characteristics. This study demonstrated that a "urine-only" approach to rapidly screen for schistosomiasis at the point of sample collection can be conducted with mobile phone microscopy (S. haematobium) coupled with POC CCA (S. mansoni). Such an approach may aid in streamlined schistosomiasis control and elimination initiatives.

Predicting Schistosomiasis Intensity in Africa: A Machine Learning Approach to Evaluate the Progress of WHO Roadmap 2030.

The World Health Organization (WHO) 2030 Roadmap aims to eliminate schistosomiasis as a public health issue, targeting reductions in the heavy intensity of infections. Previous studies, however, have predominantly used prevalence as the primary indicator of schistosomiasis. We introduce several machine learning (ML) algorithms to predict infection intensity categories, using morbidity prevalence, with the aim of assessing the elimination of schistosomiasis in Africa, as outlined by the WHO. We obtained morbidity prevalence and infection intensity data from the Expanded Special Project to Eliminate Neglected Tropical Diseases, which spans 12 countries in sub-Saharan Africa. We then used a series of ML algorithms to predict the prevalence of infection intensity categories for Schistosoma haematobium and Schistosoma mansoni, with morbidity prevalence and several relevant environmental and demographic covariates from remote-sensing sources. The optimal model had high accuracy and stability; it achieved a mean absolute error (MAE) of 0.02, a root mean square error (RMSE) of 0.05, and a coefficient of determination (R2) of 0.84 in predicting heavy-intensity prevalence for S. mansoni; and an MAE of 0.02, an RMSE of 0.04, and an R2 value of 0.81 for S. haematobium. Based on this optimal model, we found that most areas in the surveyed countries have not achieved the target of the WHO road map for 2030. The ML algorithms used in our analysis showed a high overall predictive power in estimating infection intensity for each species, and our methods provided a low-cost, effective approach to evaluating the disease target in Africa set in the WHO road map for 2030.

Improving the Cost-efficiency of Preventive Chemotherapy: Impact of New Diagnostics on Stopping Decisions for Control of Schistosomiasis.

BACKGROUND: Control of schistosomiasis (SCH) relies on the regular distribution of preventive chemotherapy (PC) over many years. For the sake of sustainable SCH control, a decision must be made at some stage to scale down or stop PC. These "stopping decisions" are based on population surveys that assess whether infection levels are sufficiently low. However, the limited sensitivity of the currently used diagnostic (Kato-Katz [KK]) to detect low-intensity infections is a concern. Therefore, the use of new, more sensitive, molecular diagnostics has been proposed. METHODS: Through statistical analysis of Schistosoma mansoni egg counts collected from Burundi and a simulation study using an established transmission model for schistosomiasis, we investigated the extent to which more sensitive diagnostics can improve decision making regarding stopping or continuing PC for the control of S. mansoni. RESULTS: We found that KK-based strategies perform reasonably well for determining when to stop PC at a local scale. Use of more sensitive diagnostics leads to a marginally improved health impact (person-years lived with heavy infection) and comes at a cost of continuing PC for longer (up to around 3 years), unless the decision threshold for stopping PC is adapted upward. However, if this threshold is set too high, PC may be stopped prematurely, resulting in a rebound of infection levels and disease burden (+45% person-years of heavy infection). CONCLUSIONS: We conclude that the potential value of more sensitive diagnostics lies more in the reduction of survey-related costs than in the direct health impact of improved parasite control.

Status of selected biochemical and coagulation profiles and platelet count in malaria and malaria-Schistosoma mansoni co-infection among patients attending at Dembiya selected Health Institutions, Northwest Ethiopia.

Malaria and schistosomiasis are infectious diseases that cause coagulation disorders, biochemical abnormalities, and thrombocytopenia. Malaria and Schistosoma mansoni co-infection cause exacerbations of health consequences and co-morbidities.This study aimed to compare the effect of malaria and Schistosoma mansoni co-infection and malaria infection on selected biochemical and coagulation profiles, and platelet count. An institutional-based comparative cross-sectional study was conducted from March 30 to August 10, 2022. A total of 70 individuals were enrolled in the study using a convenient sampling technique. Wet mount and Kato Katz techniques were conducted to detect Schistosoma mansoni in a stool sample. Blood films were prepared for the detection of plasmodium. The data was coded and entered into EpiData version 3.1 before being analyzed with SPSS version 25. An independent t test was used during data analysis. A P-value of less than 0.05 was considered statistically significant. The mean [SD] of alanine aminotransferase, aspartate aminotransferase, creatinine, total bilirubin, and direct bilirubin in the co-infected was higher than in malaria infected participants. However, the mean of total protein and glucose in co-infected was lower than in the malaria infected participants. The mean of prothrombin time, international normalization ratio, and activated partial thromboplastin time in co-infected was significantly higher, while the platelet count was lower compared to malaria infected participants. Biochemical and coagulation profiles, and platelet count status in co-infection were changed compared to malaria infected participants. Therefore, biochemical and coagulation profiles and platelet count tests should be used to monitor and manage co-infection related complications and to reduce co-infection associated morbidity and mortality.

Diagnostic tests for human Schistosoma mansoni and Schistosoma haematobium infection: a systematic review and meta-analysis.

BACKGROUND: Accurate diagnosis is pivotal for implementing strategies for surveillance, control, and elimination of schistosomiasis. Despite their low sensitivity in low-endemicity areas, microscopy-based urine filtration and the Kato-Katz technique are considered as reference diagnostic tests for Schistosoma haematobium and Schistosoma mansoni infections, respectively. We aimed to collate all available evidence on the accuracy of other proposed diagnostic techniques. METHODS: In this systematic review and meta-analysis, we searched PubMed, Embase, the Cochrane Library, and LILACS for studies published from database inception to Dec 31, 2022, investigating the sensitivity and specificity of diagnostic tests for S haematobium and S mansoni infections against Kato-Katz thick smears or urine microscopy (reference tests) involving adults (aged ≥18 years), school-aged children (aged 7 to 18 years), or preschool-aged children (aged 1 month to 7 years). We extracted raw data on true positives, true negatives, false positives, and false negatives for the diagnostic tests and data on the number of participants, study authors, publication year, journal, study design, participants' age and sex, prevalence of Schistosoma infection, and treatment status. To account for imperfect reference tests, we used a hierarchical Bayesian latent class meta-analysis to model test accuracy. FINDINGS: Overall, we included 121 studies, assessing 28 different diagnostic techniques. Most studies (103 [85%] of 121) were done in Africa, 14 (12%) in South America, one (1%) in Asia, and one (1%) in an unknown country. Compared with the reference test, Kato-Katz thick smears, circulating cathodic antigen urine cassette assay version 1 (CCA1, 36 test comparisons) had excellent sensitivity (95% [95% credible interval 88-99]) and reasonable specificity (74% [63-83]) for S mansoni. ELISA-based tests had a performance comparable to circulating cathodic antigen, but there were few available test comparisons. For S haematobium, proteinuria (42 test comparisons, sensitivity 73% [62-82]; specificity 94% [89-98]) and haematuria (75 test comparisons, sensitivity 85% [80-90]; specificity 96% [92-99]) reagent strips showed high specificity, with haematuria reagent strips having better sensitivity. Despite limited data, nucleic acid amplification tests (NAATs; eg, PCR or loop-mediated isothermal amplification [LAMP]) showed promising results with sensitivity estimates above 90%. We found an unclear risk of bias of about 70% in the use of the reference or index tests and of 50% in patient selection. All analyses showed substantial heterogeneity (I2>80%). INTERPRETATION: Although NAATs and immunological diagnostics show promise, the limited information available precludes drawing definitive conclusions. Additional research on diagnostic accuracy and cost-effectiveness is needed before the replacement of conventional tests can be considered. FUNDING: WHO and Luxembourg Institute of Health.

Immunochromatographic POC-CCA Test for the diagnosis of intestinal schistosomiasis in a high endemic region in Brazil: Differences in the interpretation of results.

The POC-CCA test is subject to variations in reading interpretations depending on the intensity of its results, and trace test reading have implications for determining prevalence. The aim of this study was to assess whether the readings obtained from the POC-CCA tests, conducted using a semi-quantitative scale (the G-score classification for test determination), exhibited concurrence with the direct visual interpretation (positive, negative, or trace) performed by two distinct analysts, using photographs from previously performed POC-CCA test carried out in the municipality of Maruim, in the state of Sergipe-Brazil, a region of high endemicity. The devices used to read the photographs were smartphones, so as to simulate field usage, and a desktop, a tool with higher image quality that would help the researchers in the evaluation and establishment of the final result at a later. In direct visual interpretation of the POC-CCA photographs, the most discordant results occurred in the identification of the trace response (T). The Kappa index established for the direct visual interpretation between the two analysts, in which T is considered as positive, in the desktop was κ=0.826 and in the smartphone, κ=0.950. When we use the G-score as a reading standardization technique and classify the results according to the manufacturer, with trace being evaluated as positive, the highest level of agreement was obtained. Some disagreement remains between the direct visual interpretation and the G-score when performed on the desktop, with more individuals being classified as negative in the direct visual interpretation, by both analysts. However, this result was not statistically significant. The use of the G-score scale proved to be an excellent tool for standardizing the readings and classifying the results according to the semi-quantitative scale showed greater concordance of results both among analysts and among the different devices used to view the photographs.

Accuracy and precision of dried urine spot method for the detection of Schistosoma mansoni circulating cathodic antigens in resource-limited settings.

BACKGROUND: The World Health Organization recommends the use of Schisto point-of-care circulating cathodic antigens (Schisto POC-CCA) for screening of Schistosoma mansoni as it offers better sensitivity than microscopy. However, there are limitation facing the use of this method including timely availability of the test cassettes. The aim of this study was to determine the reliability of dried urine spot (DUS) method for collection of urine and detection of S. mansoni using Schisto POC-CCA cassettes in a resource-limited settings. METHODS: A cross-sectional study was conducted between October and November 2022 among 250 primary school children in Sengerema District, northwestern Tanzania. S. mansoni CCA was detected in filter paper-based DUS, liquid urine using DUS Schisto POC-CCA (index), and direct urine Schisto POC-CCA (comparator) methods respectively. S. mansoni eggs in stool were detected using duplicate Kato-Katz (KK) method. The measures of accuracy were computed and compared between the index and comparator methods. The strength of agreement between inter-raters precisions was tested using Cohen's kappa (k). RESULTS: This study revealed S. mansoni prevalence rates of 28.8%, 54.0% and 50.8% by duplicate KK, direct urine Schisto POC-CCA and DUS Schisto POC-CCA methods respectively. The mean intensity of infection among infected participants was 86.3 eggs per gram of stool (EPG) ranging from 12.0 EPG to 824.0 EPG. The sensitivity of DUS Schisto POC-CCA and direct urine Schisto POC-CCA was 94.44% (95% CI: 89.15-99.74%) and 97.22% (95% CI: 93.43-100.00%) respectively. The DUS Schisto POC-CCA method had slightly higher specificity (66.85%) than direct urine Schisto POC-CCA method (63.48%). The accuracy of the DUS Schisto POC-CCA was found to be slightly high (74.80%, 95% CI: 68.94-79.06%) compared to that of direct urine Schisto POC-CCA (73.20%, 95% CI: 67.25-78.59%). There was good agreement between two laboratory technologists who performed the DUS Schisto POC-CCA method on similar samples (k = 0.80, 95% CI: 0.59-0.95). CONCLUSIONS: The DUS Schisto POC-CCA method had comparable S. mansoni detection accuracy to direct urine Schisto POC-CCA. This suggests that the method could be a potential alternative to direct urine Schisto POC-CCA for screening S. mansoni in resource-limited situations.

Identification of trans-genus biomarkers for early diagnosis of intestinal schistosomiasis and progression of gut pathology in a mouse model using metabolomics.

Schistosomiasis is one of the most devastating human diseases worldwide. The disease is caused by six species of Schistosoma blood fluke; five of which cause intestinal granulomatous inflammation and bleeding. The current diagnostic method is inaccurate and delayed, hence, biomarker identification using metabolomics has been applied. However, previous studies only investigated infection caused by one Schistosoma spp., leaving a gap in the use of biomarkers for other species. No study focused on understanding the progression of intestinal disease. Therefore, we aimed to identify early gut biomarkers of infection with three Schistosoma spp. and progression of intestinal pathology. We infected 3 groups of mice, 3 mice each, with Schistosoma mansoni, Schistosoma japonicum or Schistosoma mekongi and collected their feces before and 1, 2, 4 and 8 weeks after infection. Metabolites in feces were extracted and identified using mass spectrometer-based metabolomics. Metabolites were annotated and analyzed with XCMS bioinformatics tool and Metaboanalyst platform. From >36,000 features in all conditions, multivariate analysis found a distinct pattern at each time point for all species. Pathway analysis reported alteration of several lipid metabolism pathways as infection progressed. Disturbance of the glycosaminoglycan degradation pathway was found with the presence of parasite eggs, indicating involvement of this pathway in disease progression. Biomarkers were discovered using a combination of variable importance for projection score cut-off and receiver operating characteristic curve analysis. Five molecules met our criteria and were present in all three species: 25-hydroxyvitamin D2, 1α-hydroxy-2ß-(3-hydroxypropoxy) vitamin D3, Ganoderic acid Md, unidentified feature with m/z 455.3483, and unidentified feature with m/z 456.3516. These molecules were proposed as trans-genus biomarkers of early schistosomiasis. Our findings provide evidence for disease progression in intestinal schistosomiasis and potential biomarkers, which could be beneficial for early detection of this disease.

Laboratory and field validation of the recombinase polymerase amplification assay targeting the Schistosoma mansoni mitochondrial minisatellite region (SmMIT-RPA) for snail xenomonitoring for schistosomiasis.

Improvements in diagnostics for schistosomiasis in both humans and snail hosts are priorities to be able to reach the World Health Organization (WHO) goal of eliminating the disease as a public health problem by 2030. In this context, molecular isothermal amplification tests, such as Recombinase Polymerase Amplification (RPA), are promising for use in endemic areas at the point-of-need for their accuracy, robustness, simplicity, and time-effectiveness. The developed recombinase polymerase amplification assay targeting the Schistosoma mansoni mitochondrial minisatellite region (SmMIT-RPA) was used to detect S. mansoni DNA from both laboratory and field Biomphalaria snails. Laboratory snails were experimentally infected and used at one, seven, and 28 days post-exposure (dpe) to 10 S. mansoni miracidia to provide samples in the early pre-patent infection stage. Field samples of Biomphalaria spp. were collected from the Mucuri Valley and Jequitinhonha Valley regions in the state of Minas Gerais, Brazil, which are endemic for S. mansoni. The sensitivity and specificity of the SmMIT-RPA assay were analysed and compared with existing loop-mediated isothermal amplification (LAMP), PCR-based methods, parasitological examination of the snails, and nucleotide sequencing. The SmMIT-RPA assay was able to detect S. mansoni DNA in the experimentally infected Biomphalaria glabrata as early as one dpe to 10 miracidia. It also detected S. mansoni infections (55.5% prevalence) in the field samples with the highest accuracy (100% sensitivity and specificity) compared with the other molecular tests used as the reference. Results from this study indicate that the SmMIT-RPA assay is a good alternative test to be used for snail xenomonitoring of S. mansoni due to its high sensitivity, accuracy, and the possibility of detecting early pre-patent infection. Its simplicity and portability also make it a suitable methodology in low-resource settings.

Chronic intestinal schistosomiasis caused by co-infection with Schistosoma intercalatum and Schistosoma mansoni.

The Grand Round concerns a 24-year-old man from Zimbabwe who was studying and living in Poland. The patient had been complaining of abdominal pain, fatigue, alternating diarrhoea and constipation, and presence of blood in his stool for 3 years. The patient had the following diagnostic tests: colonoscopy, CT scan, histopathology, and parasitological and molecular tests. Results of the examinations showed that the cause of the patient's complaints was chronic intestinal schistosomiasis due to the co-infection with Schistosoma intercalatum and Schistosoma mansoni. The patient had two cycles of praziquantel therapy (Biltricide) and responded well to the treatment. In the Grand Round, we describe full diagnostics as well as clinical and therapeutic management in the patient with S intercalatum and S mansoni co-infection. This case allows us to draw attention to cases of forgotten chronic tropical diseases (including rare ones) in patients from regions with a high endemic index staying in non-endemic regions of the world for a long time. Co-infection with S intercalatum and S mansoni should be considered as a very rare clinical case.

SCHISTOACT: a protocol for an open-label, five-arm, non-inferiority, individually randomized controlled trial of the efficacy and safety of praziquantel plus artemisinin-based combinations in the treatment of Schistosoma mansoni infection.

BACKGROUND: Schistosomiasis control relies on praziquantel for preventive chemotherapy. Alternative drugs are needed for the treatment and control of schistosomiasis. Praziquantel is effective against adult schistosome worms but ineffective against larval stages of the parasite and cannot prevent re-infection or interrupt the transmission of infection. Continued reliance on praziquantel for wide-scale schistosomiasis control will likely accelerate the emergence of drug resistance. Artemisinin derivatives are effective against the juvenile stages but ineffective against adult worms. The SCHISTOACT study aimed to evaluate the efficacy and safety of praziquantel plus one of four artemisinin-based combinations in treating Schistosoma mansoni infection in Kenya. METHODS: The SCHISTOACT study is an open-label, head-to-head, five-arm, proof-of-concept, non-inferiority, individually randomized controlled trial with a follow-up of 12 weeks. A total of 540 primary school-aged children from the Mwea area, Kirinyaga County in central Kenya, diagnosed with S. mansoni infection (by Kato-Katz method) are randomly allocated (1:1:1:1:1) to a single dose of praziquantel plus a 3-day course of artesunate-sulfalene/pyrimethamine, or artesunate-amodiaquine, or artesunate plus mefloquine, or dihydroartemisinin-piperaquine, or praziquantel control arm. The primary endpoints are efficacy (cure rate, assessed by microscopy) and safety (adverse events) of each study arm 6 weeks after treatment. Secondary endpoints include cumulative cure rate, egg reduction rate, and re-infection 12 weeks after treatment. The non-inferiority margin is set at - 10 for the risk difference in cure rates between praziquantel and the combined treatment. DISCUSSION: This study assesses a strategy for repurposing artemisinin-based combination therapies (ACTs) for treating schistosomiasis. It adopts a head-to-head comparison of four different ACTs to test a non-inferiority hypothesis and to strengthen local capacity to conduct clinical trials for interventions against neglected tropical diseases. TRIAL REGISTRATION: Pan-African Clinical Trials Registry PACTR202001919442161 . Retrospectively registered on 6 January 2020.

Variants of IL6, IL10, FCN2, RNASE3, IL12B and IL17B loci are associated with Schistosoma mansoni worm burden in the Albert Nile region of Uganda.

BACKGROUND: Individuals genetically susceptible to high schistosomiasis worm burden may contribute disproportionately to transmission and could be prioritized for control. Identifying genes involved may guide development of therapy. METHODOLOGY/PRINCIPAL FINDINGS: A cohort of 606 children aged 10-15 years were recruited in the Albert Nile region of Uganda and assessed for Schistosoma mansoni worm burden using the Up-Converting Particle Lateral Flow (UCP-LF) test detecting circulating anodic antigen (CAA), point-of-care Circulating Cathodic Antigen (POC-CCA) and Kato-Katz tests. Whole genome genotyping was conducted on 326 children comprising the top and bottom 25% of worm burden. Linear models were fitted to identify variants associated with worm burden in preselected candidate genes. Expression quantitative trait locus (eQTL) analysis was conducted for candidate genes with UCP-LF worm burden included as a covariate. Single Nucleotide Polymorphism loci associated with UCP-LF CAA included IL6 rs2066992 (OR = 0.43, p = 0.0006) and rs7793163 (OR = 2.0, p = 0.0007); IL21 SNP kgp513476 (OR 1.79, p = 0.0025) and IL17B SNP kgp708159 (OR = 0.35, p = 0.0028). A haplotype in the IL10 locus was associated with lower worm burden (OR = 0.53, p = 0.015) and overlapped SNPs rs1800896, rs1800871 and rs1800872. Significant haplotypes (p<0.05, overlapping significant SNP) associated with worm burden were observed in IL6 and the Th17 pathway IL12B and IL17B genes. There were significant eQTL in the IL6, IL5, IL21, IL25 and IFNG regions. CONCLUSIONS: Variants associated with S. mansoni worm burden were in IL6, FCN2, RNASE3, IL10, IL12B and IL17B gene loci. However only eQTL associations remained significant after Bonferroni correction. In summary, immune balance, pathogen recognition and Th17 pathways may play a role in modulating Schistosoma worm burden. Individuals carrying risk variants may be targeted first in allocation of control efforts to reduce the burden of schistosomiasis in the community.

Evaluation of isotype-based serology for diagnosis of Schistosoma mansoni infection in individuals living in endemic areas with low parasite burden.

Intestinal schistosomiasis is a chronic and debilitating disease that affects public health systems worldwide. Control interventions to reduce morbidity primarily involve the diagnosis and treatment of infected individuals. However, the recommended Kato-Katz (KK) parasitological method shows low sensitivity in individuals with low parasite loads and is not useful for monitoring elimination of parasite transmission at later stages. In the current study, we evaluated the accuracy of serum reactivity levels of different immunoglobulin isotypes in an enzyme-linked immunosorbent assay (ELISA), utilizing Schistosoma mansoni crude extracts, with the aim to improve the diagnosis of infected individuals with low parasite loads. The serum reactivity of IgM and IgG subclass antibodies (IgG1, IgG3, and IgG4) against soluble adult worm and egg antigen preparations was evaluated in residents from a schistosomiasis-endemic area in northern Minas Gerais, Brazil. The parasitological status of the study population was determined through fecal examination with multiple parasitological tests to create a consolidated reference standard (CRS) plus a fecal DNA detection test (q-PCR). Twelve months after praziquantel treatment, a second serum sample was obtained from the population for reexamination. A two-graph receiver operating characteristic curve (TG-ROC) analysis was performed using the serum reactivity of non-infected endemic controls and egg-positive individuals, and the cut-off value was established based on the intersection point of the sensibility and specificity curves in TG-ROC analyses. The diagnostic accuracy of each serological test was evaluated in relation to the parasitological CRS and to the combination of CRS plus qPCR results. The data revealed that serum reactivity of IgM and IgG3 against S. mansoni antigens did not allow identification of infected individuals from the endemic area. In contrast, serum IgG1 and IgG4-reactivity against schistosome antigens could distinguish between infected and non-infected individuals, with AUC values ranging between 0.728-0.925. The reactivity of IgG4 anti-soluble egg antigen - SEA (sensitivity 79 %, specificity 69 %, kappa = 0.49) had the best diagnostic accuracy, showing positive reactivity in more than 75 % of the infected individuals who eliminated less than 12 eggs per gram of feces. Moreover, serum IgG4 reactivity against SEA and against soluble worm antigen preparation (SWAP) was significantly reduced in the serum of infected individuals after 12 months of confirmed parasitological cure and in the absence of re-infection. These results reinforce that the described IgG4 anti-SEA ELISA assay is a sensitive alternative for the diagnosis of active intestinal schistosomiasis in individuals from endemic areas, including in those with a very low parasite load.

Test-Treat-Track-Test-Treat Strategy for Control of Schistosomiasis in Two Low-Prevalence Villages in Northwestern Tanzania.

Mass drug administration of praziquantel becomes a less attractive strategy for elimination of schistosomiasis in low-prevalence areas due to cost implications and low treatment compliance. We aimed to determine the feasibility of a Test-Treat-Track-Test-Treat (5T) strategy in two low-prevalence villages; the 5T strategy has been successfully implemented in diseases such as malaria. A total of 200 school children aged 6-12 years were randomly selected from two schools and tested for Schistosoma mansoni infection using the point-of-care circulating cathodic antigen test. Schistosoma mansoni-positive children, referred to as first-generation cases (FGCs), were tracked and treated including up to five members of their families. Second-generation cases, identified by the FGCs as their close, non-relative contacts, were also tracked, tested, and treated, including up to five members of their families. The prevalence of schistosomiasis among screened FGCs was 16.5% (33/200) in both villages. Twenty-four FGCs were included in the study. Prevalence among 94 contacts of FGCs was 46.8% (44/94). The proportion was higher in Muda than Bulunga village (61.2% versus 31.1%, χ2 = 10.6611, P = 0.005). Prevalence among SGCs and their contacts was 37.5% (9/24) and 47.1% (49/104), respectively. Overall, the 5T strategy identified 102 additional cases out of 222 tracked from FGCs, 95% of whom were treated, at a total time of 52 hours. Our data demonstrate the potential of the 5T strategy in identifying and treating additional cases in the community and hence its practicality in schistosomiasis control in low-prevalence settings at relatively low time and resources investment.

Development and evaluation of an indirect ELISA using a multiepitope antigen for the diagnosis of intestinal schistosomiasis.

The laboratory diagnosis of intestinal schistosomiasis, carried out by detecting parasite eggs in feces, has low sensitivity when applied to individuals with low parasitic load. Serological tests can be more sensitive for the diagnosis of the disease. Therefore, the objective of this work was to develop and evaluate an ELISA-based immunoenzymatic assay, using a Schistosoma mansoni multiepitope antigen (ELISA IgG anti-SmME). For this, the amino acid sequences of S. mansoni cathepsin B and asparaginyl endopeptidase were submitted to the prediction of B cell epitopes and, together with peptide sequences obtained from earlier works, were used in the construction of a minigene. The multiepitope protein was expressed in Escherichia coli and the performance of the ELISA IgG anti-SmME for schistosomiasis was evaluated using serum samples from 107 individuals either egg positive or negative. In addition, 11 samples from individuals with other helminth infections were included. The ELISA IgG anti-SmME showed a sensitivity of 81.1% and a specificity of 46.1%. Further analysis revealed a 77.2% sensitivity in diagnosis of individuals with egg counts of ≤12 epg (eggs per gram feces) and 87.5% for individuals with 13­99 epg. It is worth mentioning that, to our knowledge, this was the first study using a multiepitope recombinant antigen in an ELISA for diagnosis of intestinal schistosomiasis, which demonstrated promising results in the diagnosis of individuals with low parasitic loads.

A review of serological tests available in Brazil for intestinal schistosomiasis diagnosis.

The World Health Organization (WHO) roadmap and recommendations for elimination of schistosomiasis were recently updated. With significant reductions in the prevalence and intensity of schistosomiasis infections worldwide, there is a need for more sensitive diagnostic methods. There are a few remaining transmission hotspots in Brazil, although low endemicity settings comprise most of the endemic localities. For the latter, serology may represent a tool for population screening which could help eliminate transmission of schistosomiasis. Here, we review serology tests currently available in Brazil from both public health and private laboratories: immunofluorescent antibody tests (IFATs) on adult worm sections and enzyme-linked immunosorbent assays (ELISAs) with soluble egg and adult worm antigens. Both in-house and commercially available tests have received less than adequate performance evaluations. Our review of immediate basic and operational research goals may help identify local adjustments that can be made to improve control interventions aimed at elimination of schistosomiasis as a public health problem.

Efficacy, safety, and palatability of arpraziquantel (L-praziquantel) orodispersible tablets in children aged 3 months to 6 years infected with Schistosoma in Côte d'Ivoire and Kenya: an open-label, partly randomised, phase 3 trial.

BACKGROUND: WHO has underlined the need for a child-friendly treatment for schistosomiasis, a prevalent parasitic disease in low-income and middle-income countries. After successful phase 1 and 2 trials, we aimed to evaluate the efficacy, safety, palatability, and pharmacokinetics of arpraziquantel (L-praziquantel) orodispersible tablets for preschool-aged children. METHODS: This open-label, partly randomised, phase 3 study was conducted at two hospitals in Côte d'Ivoire and Kenya. Children with a minimum bodyweight of 5 kg in those aged 3 months to 2 years and 8 kg in those aged 2-6 years were eligible. In cohort 1, participants aged 4-6 years infected with Schistosoma mansoni were randomly assigned (2:1) to receive a single dose of oral arpraziquantel 50 mg/kg (cohort 1a) or oral praziquantel 40 mg/kg (cohort 1b) using a computer-generated randomisation list. Cohorts 2 (aged 2-3 years) and 3 (aged 3 months to 2 years) infected with S mansoni, and the first 30 participants in cohort 4a (aged 3 months to 6 years) infected with Schistosoma haematobium, received a single dose of oral arpraziquantel 50 mg/kg. After follow-up assessments, arpraziquantel was increased to 60 mg/kg (cohort 4b). Laboratory personnel were masked to the treatment group, screening, and baseline values. S mansoni was detected using a point-of-care circulating cathodic antigen urine cassette test and confirmed using the Kato-Katz method. The primary efficacy endpoint was clinical cure rate at 17-21 days after treatment in cohorts 1a and 1b, measured in the modified intention-to-treat population and calculated using the Clopper-Pearson method. This study is registered with ClinicalTrials.gov, NCT03845140. FINDINGS: Between Sept 2, 2019, and Aug 7, 2021, 2663 participants were prescreened and 326 were diagnosed with S mansoni or S haematobium. 288 were enrolled (n=100 in cohort 1a, n=50 in cohort 1b, n=30 in cohort 2, n=18 in cohort 3, n=30 in cohort 4a, and n=60 in cohort 4b), but eight participants received antimalarial drugs and were excluded from the efficacy analyses. The median age was 5·1 years (IQR 4·1-6·0) and 132 (47%) of 280 participants were female and 148 (53%) were male. Cure rates with arpraziquantel were similar to those with praziquantel (87·8% [95% CI 79·6-93·5] in cohort 1a vs 81·3% [67·4-91·1] in cohort 1b). No safety concerns were identified during the study. The most common drug-related treatment-emergent adverse events were abdominal pain (41 [14%] of 288 participants), diarrhoea (27 [9%]), vomiting (16 [6%]), and somnolence (21 [7%]). INTERPRETATION: Arpraziquantel, a first-line orodispersible tablet, showed high efficacy and favourable safety in preschool-aged children with schistosomiasis. FUNDING: The Global Health Innovative Technology Fund, the European and Developing Countries Clinical Trials Partnership, and the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: 10.13039/100009945).

Subclinical signs of podocyte injury associated with Circulating Anodic Antigen (CAA) in Schistosoma mansoni-infected patients in Brazil.

BACKGROUND: The long-term effects of schistosomiasis on the glomerulus may contribute to the development of chronic kidney disease. This study aimed to investigate baseline Schistosoma mansoni-Circulating Anodic Antigen (CAA) levels and their association with kidney biomarkers related to podocyte injury and inflammation in long-term follow-up after praziquantel (PZQ) treatment. METHODS: Schistosoma infection was diagnosed by detecting CAA in urine using a quantitative assay based on lateral flow using luminescent up-converting phosphor reporter particles. A cutoff threshold of 0.1 pg/mL CAA was used to diagnose Schistosoma infection (baseline) in a low-prevalence area in Ceará, Northeast, Brazil. Two groups were included: CAA-positive and CAA-negative individuals, both of which received a single dose of PZQ at baseline. Urinary samples from 55 individuals were evaluated before (baseline) and at 1, 2, and 3 years after PZQ treatment. At all time points, kidney biomarkers were quantified in urine and adjusted for urinary creatinine levels. RESULTS: CAA-positive patients had increased baseline albuminuria and proteinuria and showed greater associations between kidney biomarkers. CAA levels correlated only with Vascular Endothelial Growth Factor (VEGF) (podocyte injury) levels. Increasing trends were observed for malondialdehyde (oxidative stress), monocyte chemoattractant protein-1 (inflammation marker), and VEGF. In the follow-up analysis, no relevant differences were observed in kidney biomarkers between the groups and different periods. CONCLUSIONS: S. mansoni-infected individuals presented subclinical signs of glomerular damage that may reflect podocyte injury. However, no causal effect on long-term renal function was observed after PZQ treatment.