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.

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.

School-based preventive chemotherapy program for schistosomiasis and soil-transmitted helminth control in Angola: 6-year impact assessment.

BACKGROUND: A school preventive chemotherapy (PC) program for soil-transmitted helminths (STHs) and schistosomiasis has operated in Huambo, Uige and Zaire provinces, Angola, since 2013 and 2014, respectively; complemented by a school water, sanitation and hygiene (WASH) program in a subset of schools from 2016. Conducted in 2021, this is the first impact assessment of the school program for the control of schistosomiasis and STHs. METHODOLOGY/PRINCIPAL FINDINGS: A two-stage cluster design was used to select schools and schoolchildren for parasitological and WASH surveys. The rapid diagnostic tests (RDTs), point of care circulating cathodic antigen (POC-CCA) and Hemastix, were used to estimate Schistosoma mansoni and Schistosoma haematobium prevalence, respectively. Kato Katz was used to detect STHs, and quantify STH and S. mansoni infections. Urine filtration was used to quantify S. haematobium infections. Prevalence, infection intensity, relative prevalence reduction and egg reduction rates were calculated for schistosomiasis and STHs. Cohen's Kappa co-efficient was used to assess agreement between RDTs and microscopy. Chi-square or Fisher's exact test was used to compare WASH indicators in WASH-supported and WASH-unsupported schools. Overall, 17,880 schoolchildren (599 schools) and 6,461 schoolchildren (214 schools) participated in the schistosomiasis and STH surveys, respectively. Prevalence of any schistosomiasis in Huambo was 29.6%, Uige 35.4%, and Zaire 28.2%. Relative reduction in schistosomiasis prevalence from 2014 for Huambo was 18.8% (95% confidence interval (CI) 8.6, 29.0), Uige -92.3% (95%CI -162.2, -58.3), and Zaire -14.0% (95%CI -48.6, 20.6). Prevalence of any STH in Huambo was 16.3%, Uige 65.1%, and Zaire 28.2%. Relative reduction in STH prevalence for Huambo was -28.4% (95%CI -92.1, 35.2), Uige -10.7% (95%CI -30.2, 8.8), and Zaire -20.9% (95%CI -79.5, 37.8). A higher proportion of WASH-supported schools had improved water sources, and toilet and handwashing facilities compared to WASH-unsupported schools. CONCLUSIONS/SIGNIFICANCE: The limited impact this school program has had in controlling schistosomiasis and STHs identifies the need for a comprehensive understanding of individual, community, and environmental factors associated with transmission, and consideration for a community-wide control program.

Risk clusters of Schistosoma mansoni infection in an endemic state of Brazil: space-time modelling and association with socio-economic and environmental factors.

BACKGROUND: We analysed the spatial distribution and the socio-economic and environmental factors (SEFs) associated with Schistosoma mansoni infection in the state of Alagoas, an important tourist area in northeastern Brazil. METHODS: We conducted an ecological time-series study (2007-2016) on schistosomiasis cases and SEFs. We evaluated the temporal trends of schistosomiasis cases (annual percentage change [APC]) and their correlation with SEFs. Spatial analysis maps were built using QGIS and TerraView software. RESULTS: We observed that 4.9% of the municipalities had a high prevalence of S. mansoni infection and were located mainly in the coastal strip of Alagoas state. The positivity rate for schistosomiasis decreased during the period (8.1% in 2007 to 4.9% in 2016; APC=-5.71). There was a reduction in the number of tests performed (APC=-5.05). There was a negative correlation between S. mansoni infection and the municipal human development index (ρ=-0.34) and schooling rate (ρ=-0.24). The main species of snail was Biomphalaria glabrata (94.79%), but Biomphalaria straminea showed a higher percentage of S. mansoni detection (10.11%). Lastly, Biomphalaria tenagophila specimens were identified for the first time in Alagoas (n=28). CONCLUSIONS: Despite a reduction in the number of cases, intestinal schistosomiasis still represents a serious public health concern in Alagoas. It urgently requires planning and improvements in diagnosis, prevention programs and the state's socio-economic indicators.

Schistosomiasis messaging in endemic communities: Lessons and implications for interventions from rural Uganda, a rapid ethnographic assessment study.

BACKGROUND: Over 240 million people are infected with schistosomiasis, the majority in sub-Saharan Africa. In Uganda, high infection rates exist in communities on the shores of Lake Victoria. Praziquantel mass drug administration (MDA) delivered by village health teams is the mainstay of schistosomiasis control. However, treatment uptake remains suboptimal, with many people unaware of treatment or thinking it is only for children. Furthermore, people are often rapidly reinfected post-treatment due to continued exposure. In three Schistosoma mansoni high endemicity lake-shore communities in Mayuge district, Eastern Uganda, we investigated the sources of schistosomiasis information, remembered content of information, and the perception of information and related practices towards the control of schistosomiasis. METHODS AND PRINCIPAL FINDINGS: Data were collected from September 2017 to March 2018 using a rapid ethnographic assessment that included transect walks, observations, individual in-depth interviews and focus group discussions. Data were analysed thematically using iterative categorisation. We found that the main sources of schistosomiasis information included health workers at government facilities, village health teams, teachers, and radio programmes produced by the Ministry of Health. These messages described the symptoms of schistosomiasis, but did not mention the side effects of praziquantel treatment. Despite this messaging, the main cause of the disease and transmission was unclear to most participants. The translation of schistosomiasis on the radio into the local language 'ekidada'-meaning swollen stomach-increased, rather than reduced, confusion about the cause(s) of schistosomiasis, due to believed links between ekidada and witchcraft, and prompted a reluctance to engage with treatment or preventative efforts. CONCLUSION AND SIGNIFICANCE: This study highlights gaps in schistosomiasis messaging. We recommend MDA is complemented by effective, evidence-based messaging on schistosomiasis transmission, prevention, and treatment, that is sensitive to local language and context issues, resulting in clear, concise, and consistent messages, to increase effectiveness.

Socioeconomic determinants of Schistosoma mansoni infection using multiple correspondence analysis among rural western Kenyan communities: Evidence from a household-based study.

BACKGROUND: Socioeconomic inequality including wealth distribution is a barrier to implementation of health policies. Wealth distribution can be measured effectively using household data on durable assets. Compared to other methods of analysing Socio-economic Status (SES) using durable assets, Multiple Correspondence Analysis (MCA) can create more reliable wealth quintiles. We therefore evaluated socioeconomic determinants of Schistosoma mansoni using MCA on household data among adult population in western Kenya. The hypothesis of this study was that MCA would be a useful predictor of S. mansoni prevalence and/or intensity. METHODOLOGY: Twelve villages, 6 villages that had showed the greatest decrease in S. mansoni prevalence (Responder villages) and 6 villages that showed relatively lower decrease (Hotspot villages) between the year 2011 and 2015 were randomly selected for this study. This was according to a previous Schistosomiasis Consortium for Operational Research and Elimination (SCORE) report from western Kenya. From each village, convenience sampling was used to identify 50 adults from 50 households for inclusion in this study. An interview with a questionnaire based upon MCA indicators was conducted. One stool sample from each of the 600 adults was examined based on four slides for S. mansoni eggs using Kato Katz technique. Mean Eggs per gram(EPG) was calculated by taking the average of the readings from the four slides. A log binomial regression model was used to identify the influence of the various age-groups(<30 years, 30-60 years and >60 years), household size, wealth class, occupation, education status, main water supply, sex and sub-county of residence on S. mansoni infection. EPG was then compared across variables that were significant based on multivariate log binomial model analysis using a mixed model. PRINCIPAL FINDINGS: Overall prevalence of S. mansoni was 41.3%. Significantly higher prevalence of S. mansoni were associated with males, those aged below 30 years, those who use unsafe water sources (unprotected wells, lakes and rivers), residents of Rachuonyo North, Hotspot villages and those earning livelihood from fishing. Only sex and household size were significant predictors in the multivariate model. Males were associated with significantly higher prevalence compared to the females (aPR = 1.37; 95% CI = 1.14-1.66). In addition, households with at least four persons had higher prevalence compared to those with less than four (aPR = 1.29; 95% CI = 1.03-1.61). However, there was no difference in prevalence between the wealth classes(broadly divided into poor and less poor categories). Intensity of infection (Mean EPG)was also significantly higher among males, younger age group, Rachuonyo North residents and Hotspot Villages. CONCLUSION: Socioeconomic status based on an MCA model was not a contributing factor to S. mansoni prevalence and/or intensity possibly because the study populations were not sufficiently dissimilar. The use of convenience sampling to identify participants could also have contributed to the lack of significant findings.

Evaluating survey designs for targeting preventive chemotherapy against Schistosoma haematobium and Schistosoma mansoni across sub-Saharan Africa: a geostatistical analysis and modelling study.

BACKGROUND: Schistosomiasis control programmes primarily use school-based surveys to identify areas for mass drug administration of preventive chemotherapy. However, as the spatial distribution of schistosomiasis can be highly focal, transmission may not be detected by surveys implemented at districts or larger spatial units. Improved mapping strategies are required to accurately and cost-effectively target preventive chemotherapy to remaining foci across all possible spatial distributions of schistosomiasis. METHODS: Here, we use geostatistical models to quantify the spatial heterogeneity of Schistosoma haematobium and S. mansoni across sub-Saharan Africa using the most comprehensive dataset available on school-based surveys. Applying this information to parameterise simulations, we assess the accuracy and cost of targeting alternative implementation unit sizes across the range of plausible schistosomiasis distributions. We evaluate the consequences of decisions based on survey designs implemented at district and subdistrict levels sampling different numbers of schools. Cost data were obtained from field surveys conducted across multiple countries and years, with cost effectiveness evaluated as the cost per correctly identified school. RESULTS: Models identified marked differences in prevalence and spatial distributions between countries and species; however, results suggest implementing surveys at subdistrict level increase the accuracy of treatment classifications across most scenarios. While sampling intensively at the subdistrict level resulted in the highest classification accuracy, this sampling strategy resulted in the highest costs. Alternatively, sampling the same numbers of schools currently recommended at the district level but stratifying by subdistrict increased cost effectiveness. CONCLUSIONS: This study provides a new tool to evaluate schistosomiasis survey designs across a range of transmission settings. Results highlight the importance of considering spatial structure when designing sampling strategies, illustrating that a substantial proportion of children may be undertreated even when an implementation unit is correctly classified. Control programmes need to weigh the increased accuracy of more detailed mapping strategies against the survey costs and treatment priorities.

Application of Schistosomiasis Consortium for Operational Research and Evaluation Study Findings to Refine Predictive Modeling of Schistosoma mansoni and Schistosoma haematobium Control in Sub-Saharan Africa.

An essential mission of the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was to help inform global health practices related to the control and elimination of schistosomiasis. To provide more accurate, evidence-based projections of the most likely impact of different control interventions, whether implemented alone or in combination, SCORE supported mathematical modeling teams to provide simulations of community-level Schistosoma infection outcomes in the setting of real or hypothetical programs implementing multiyear mass drug administration (MDA) for parasite control. These models were calibrated using SCORE experience with Schistosoma mansoni and Schistosoma haematobium gaining and sustaining control studies, and with data from comparable programs that used community-based or school-based praziquantel MDA in other parts of sub-Saharan Africa. From 2010 to 2019, models were developed and refined, first to project the likely SCORE control outcomes, and later to more accurately reflect impact of MDA across different transmission settings, including the role of snail ecology and the impact of seasonal rainfall on snail abundance. Starting in 2014, SCORE modeling projections were also compared with the models of colleagues in the Neglected Tropical Diseases Modelling Consortium. To explore further possible improvement to program-based control, later simulations examined the cost-effectiveness of combining MDA with environmental snail control, and the utility of early impact assessment to more quickly identify persistent hot spots of transmission. This article provides a nontechnical summary of the 11 SCORE-related modeling projects and provides links to the original open-access articles describing model development and projections relevant to schistosomiasis control policy.

Mapping Schistosoma mansoni endemicity in Rwanda: a critical assessment of geographical disparities arising from circulating cathodic antigen versus Kato-Katz diagnostics.

BACKGROUND: Schistosomiasis is a neglected tropical disease caused by Schistosoma parasites. Intervention relies on identifying high-risk regions, yet rapid Schistosoma diagnostics (Kato-Katz stool assays (KK) and circulating cathodic antigen urine assays (CCA)) yield different prevalence estimates. We mapped S. mansoni prevalence and delineated at-risk regions using a survey of schoolchildren in Rwanda, where S. mansoni is an endemic parasite. We asked if different diagnostics resulted in disparities in projected infection risk. METHODS: Infection data was obtained from a 2014 Rwandan school-based survey that used KK and CCA diagnostics. Across 386 schools screened by CCA (N = 19,217). To allow for uncertainty when interpreting ambiguous CCA trace readings, which accounted for 28.8% of total test results, we generated two presence-absence datasets: CCA trace as positive and CCA trace as negative. Samples (N = 9,175) from 185 schools were also screened by KK. We included land surface temperature (LST) and the Normalized Difference Vegetation and Normalized Difference Water Indices (NDVI, NDWI) as predictors in geostatistical regressions. FINDINGS: Across 8,647 children tested by both methods, prevalence was 35.93% for CCA trace as positive, 7.21% for CCA trace as negative and 1.95% for KK. LST was identified as a risk factor using KK, whereas NDVI was a risk factor for CCA models. Models predicted high endemicity in Northern and Western regions of Rwanda, though the CCA trace as positive model identified additional high-risk areas that were overlooked by the other methods. Estimates of current burden for children at highest risk (boys aged 5-9 years) varied by an order of magnitude, with 671,856 boys projected to be infected by CCA trace as positive and only 60,453 projected by CCA trace as negative results. CONCLUSIONS: Our findings show that people in Rwanda's Northern, Western and capital regions are at high risk of S. mansoni infection. However, variation in identification of environmental risk factors and delineation of at-risk regions using different diagnostics likely provides confusing messages to disease intervention managers. Further research and statistical analyses, such as latent class analysis, can be used to improve CCA result classification and assess its use in guiding treatment regimes.

Estimating helminth burdens using sibship reconstruction.

BACKGROUND: Sibship reconstruction is a form of parentage analysis that can be used to identify the number of helminth parental genotypes infecting individual hosts using genetic data on only their offspring. This has the potential to be used for estimating individual worm burdens when adult parasites are otherwise inaccessible, the case for many of the most globally important human helminthiases and neglected tropical diseases. Yet methods of inferring worm burdens from sibship reconstruction data on numbers of unique parental genotypes are lacking, limiting the method's scope of application. RESULTS: We developed a novel statistical method for estimating female worm burdens from data on the number of unique female parental genotypes derived from sibship reconstruction. We illustrate the approach using genotypic data on Schistosoma mansoni (miracidial) offspring collected from schoolchildren in Tanzania. We show how the bias and precision of worm burden estimates critically depends on the number of sampled offspring and we discuss strategies for obtaining sufficient sample sizes and for incorporating judiciously formulated prior information to improve the accuracy of estimates. CONCLUSIONS: This work provides a novel approach for estimating individual-level worm burdens using genetic data on helminth offspring. This represents a step towards a wider scope of application of parentage analysis techniques. We discuss how the method could be used to assist in the interpretation of monitoring and evaluation data collected during mass drug administration programmes targeting human helminthiases and to help resolve outstanding questions on key population biological processes that govern the transmission dynamics of these neglected tropical diseases.

Microarray assessment of N-glycan-specific IgE and IgG profiles associated with Schistosoma mansoni infection in rural and urban Uganda.

Core ß-1,2-xylose and α-1,3-fucose are antigenic motifs on schistosome N-glycans, as well as prominent IgE targets on some plant and insect glycoproteins. To map the association of schistosome infection with responses to these motifs, we assessed plasma IgE and IgG reactivity using microarray technology among Ugandans from rural Schistosoma mansoni (Sm)-endemic islands (n = 209), and from proximate urban communities with lower Sm exposure (n = 62). IgE and IgG responses to core ß-1,2-xylose and α-1,3-fucose modified N-glycans were higher in rural versus urban participants. Among rural participants, IgE and IgG to core ß-1,2-xylose were positively associated with Sm infection and concentration peaks coincided with the infection intensity peak in early adolescence. Responses to core α-1,3-fucose were elevated regardless of Sm infection status and peaked before the infection peak. Among urban participants, Sm infection intensity was predominantly light and positively associated with responses to both motifs. Principal component and hierarchical cluster analysis reduced the data to a set of variables that captured core ß-1,2-xylose- and α-1,3-fucose-specific responses, and confirmed associations with Sm and the rural environment. Responses to core ß-1,2-xylose and α-1,3-fucose have distinctive relationships with Sm infection and intensity that should further be explored for associations with protective immunity, and cross-reactivity with other exposures.

The cost of a disease targeted for elimination in Brazil: the case of schistosomiasis mansoni.

BACKGROUND: Schistosomiasis mansoni is a poverty-related parasitic infection that has a variety of clinical manifestations. We consider the disability and deaths caused by schistosomiasis unacceptable for a tool-ready disease. Its condition in Brazil warrants an analysis that will enable better understanding of the local health losses and contribute to the complex decision-making process. OBJECTIVE: This study estimates the cost of schistosomiasis in Brazil in 2015. METHODS: We conducted a cost of illness study of schistosomiasis mansoni in Brazil in 2015 based on a prevalence approach and from a societal perspective. The study included 26,499 schistosomiasis carriers, 397 hepatosplenic cases, 48 cases with the neurological form, 284 hospitalisations, and 11,368.26 years of life lost (YLL) of which 5,187 years are attributable to economically active age groups. RESULTS: The total cost of schistosomiasis mansoni in Brazil was estimated to be US$ 41,7million in 2015 with 94.61% of this being indirect costs. CONCLUSIONS: The economic burden of schistosomiasis mansoni in Brazil is high and results in the loss of productivity. Its persistence in Brazil is a challenge to public health and requires inter-sectorial interventions in areas such as indoor water supply, basic sanitation, and education.

Quality of life and quality-adjusted life years of chronic schistosomiasis mansoni patients in Brazil in 2015.

Background: Measures of health-related quality of life (HRQoL) have been used to express the impact of neglected diseases and to generate indicators for health economic assessments. Schistosomiasis mansoni is a neglected disease with various clinical manifestations, including severe repercussions, caused by parasitic worms. Here we describe the quality of life of chronic schistosomiasis mansoni patients and estimate the quality-adjusted life years (QALYs) associated with chronic schistosomiasis mansoni in Brazil in 2015. Methods: A HRQoL study was carried out using the three-level European Quality of Life 5-Dimensions (EQ-5D-3L) questionnaire in 147 chronic schistosomiasis mansoni patients at an outpatient monitoring facility of an endemic state for schistosomiasis. Results: Losses in HRQoL were observed in all five dimensions of the EQ-5D-3L. Patients >60 y and 40-49 y of age reported the highest frequencies of problems. The average utility index was 0.71, and the median index was significantly lower among female patients and patients with comorbidities (0.68; p<0.05) compared with the entire sample. Approximately 26.7 QALYs were estimated for the study population and 31.2 QALYs for the chronic schistosomiasis mansoni patients in Brazil. Conclusions: The advanced forms of schistosomiasis mansoni, even during treatment, contribute to important health losses in the population dealing with the disease.

Socioenvironmental factors associated with Schistosoma mansoni infection and intermediate hosts in an urban area of northeastern Brazil.

Schistosomiasis, which is caused by trematodes of the genus Schistosoma and by the species Schistosoma mansoni in Brazil, is transmitted primarily by Biomphalaria glabrata mollusks. Infections occur in humans and mollusks in freshwater environments contaminated with feces from infected humans. This study aimed to evaluate potential foci of schistosomiasis based on the identification of infection sites for the snails, factors that increased the human infection probability of S. mansoni infection, and the relationship of the disease with abiotic, biotic, and sociocultural factors. The study was conducted in an urban area on the northeast coast of Brazil; this location was chosen based on the following factors: the presence of B. glabrata, nearby freshwater, and the absence of sewer treatment. A parasitological analysis was performed to evaluate infections of the mollusks and residents inside the perimeter defined by the collection points. Questionnaires were applied to obtain demographic data and to identify behaviors that led to human infection. To verify the contamination of freshwater by human feces, a microbiological analysis of the water was performed at the mollusk collection points to determine the rate of contamination with fecal coliforms. A total of 10,270 B. glabrata mollusks were collected between August 2013 and August 2014, of which 8.8% were positive for S. mansoni; the prevalence ranged from 0 to 34.5% over the study period. A total of 232 coprological samples from the residents were analyzed. The S. mansoni infection prevalence rate was 16.4%, and the S. mansoni parasitic load in the infected residents was 54.9 eggs per gram of feces on average. Males were more affected by the parasite, especially in the 8-17-year-old age range. Thermotolerant coliforms were observed at the mollusk collection sites, which indicated that freshwater and sewage were in continuous contact. This contamination indicated poor sanitary conditions, as was previously observed, which could be combined with detrimental behavior due to the residents' habits. These conditions cause a predisposition for both intermediate and definitive infections of the hosts by creating a socioenvironmental scenario that is conducive to the formation and maintenance of potential schistosomiasis foci. This and similar areas deserve special attention from the government with an aim of improving sanitation services and local resident knowledge to prevent future contamination.

A field survey using LAMP assay for detection of Schistosoma mansoni in a low-transmission area of schistosomiasis in Umbuzeiro, Brazil: Assessment in human and snail samples.

BACKGROUND: In Brazil, schistosomiasis is a parasitic disease of public health relevance, mainly in poor areas where Schistosoma mansoni is the only human species encountered and Biomphalaria straminea is one of the intermediate host snails. A nested-PCR based on a specific mitochondrial S. mansoni minisatellite DNA region has been successfully developed and applied as a reference method in Brazil for S. mansoni detection, mainly in host snails for epidemiological studies. The amplification efficiency of LAMP is known to be higher than PCR. The present work aimed to assess the utility of our previously described SmMIT-LAMP assay for S. mansoni detection in human stool and snail samples in a low-transmission area of schistosomiasis in the municipality of Umbuzeiro, Paraíba State, Northeast Region of Brazil. METHODOLOGY/PRINCIPAL FINDINGS: A total of 427 human stool samples were collected during June-July 2016 in the municipality of Umbuzeiro and an overall prevalence of 3.04% (13/427) resulted positive by duplicate Kato-Katz thick smear. A total of 1,175 snails identified as Biomphalaria straminea were collected from 14 breeding sites along the Paraíba riverbank and distributed in 46 pools. DNA from human stool samples and pooled snails was extracted using the phenol/chloroform method. When performing the SmMIT-LAMP assay a total of 49/162 (30.24%) stool samples resulted positive, including 12/13 (92.31%) that were Kato-Katz positive and 37/149 (24.83%) previously Kato-Katz negative. By nested-PCR, only 1/46 pooled DNA snail samples was positive. By SmMIT-LAMP assay, the same sample also resulted positive and an additional one was positive from a different breeding site. Data of human and snail surveys were used to build risk maps of schistosomiasis incidence using kernel density analysis. CONCLUSIONS/SIGNIFICANCE: This is the first study in which a LAMP assay was evaluated in both human stool and snail samples from a low-transmission schistosomiasis-endemic area. Our SmMIT-LAMP proved to be much more efficient in detection of S. mansoni in comparison to the 'gold standard' Kato-Katz method in human stool samples and the reference molecular nested-PCR in snails. The SmMIT-LAMP has demonstrated to be a useful molecular tool to identify potential foci of transmission in order to build risk maps of schistosomiasis.

Systematic review and meta-analysis on Schistosoma mansoni infection prevalence, and associated risk factors in Brazil.

We performed a systematic review and meta-analysis on the prevalence and factors associated with Schistosoma mansoni infection in Brazil. We searched the PubMed, Web of Science and Latin-American and Caribbean System on Health Sciences Information (LILACS) databases, scientific publications articles, according to The PRISMA Statement, from 2000 to 2016. A total of 27 studies were included according to the established criteria. The prevalence of S. mansoni infection varied widely, from 0·1 to 73·1%, based on Kato-Katz technique. Of the identified studies, 42·9% were performed in the state of Minas Gerais, and 33·3% were performed in the northeast region of Brazil. We identified sex, age, education level, family income, contact with water and the presence of the intermediate host snail as major risk factors associated with infection. The meta-analysis summarized a high prevalence rate pooled for Schistosoma mansoni. On the other hand, the analysis of the subgroup showed a highly significant reduction of the prevalence rate after control measures. The epidemiological factors evidenced in the studies show the influence of environmental and social conditions on the occurrence of schistosomiasis.

The burden, pattern and factors that contribute to periportal fibrosis in HIV-infected patients in an S. mansoni endemic rural Uganda.

INTRODUCTION: Both Human Immunodeficiency Virus (HIV) and S.mansoni infections are common in Uganda and can cause liver disease. No study has determined co-infection significance in Uganda. We carried out a study on the burden, pattern and factors that contribute to peri-portal fibrosis (PPF) in HIV infected patients attending a Primary healthcare setting at Pakwach. METHODOLOGY: We conducted a cross-sectional study in the HIV clinic at Pakwach health centre IV. Data on demographics, contact with the Nile, CD4+ cell count, ART and alcohol use were collected. Urinary Circulating Cathodic Antigen (CCA), was done for S. Mansoni detection. Liver scan was done for presence and pattern of PPF. HBsAg testing was performed on all participants. Data was analyzed using Stata Version 10. RESULTS: We enrolled 299 patients, median age 39 years (IQR 16), most were female, 210 (73%). Overall, 206 (68.9%) had PPF, majority 191 (92.7%) had pattern c, either alone (63 participants) or in combination with pattern d (128 participants). Age of 30-50 years was significantly associated with PPF (OR 2.28 p-value-0.003). CONCLUSION: We found high prevalence of S. mansoni and PPF in the HIV infected population and age was a significant factor for PPF. We recommend all HIV infected patients be examined routinely for S. mansoni infection for early anti-schistosomal treatment.

Estimating the prevalence and intensity of Schistosoma mansoni infection among rural communities in Western Tanzania: The influence of sampling strategy and statistical approach.

BACKGROUND: Schistosoma mansoni is a parasite of major public health importance in developing countries, where it causes a neglected tropical disease known as intestinal schistosomiasis. However, the distribution of the parasite within many endemic regions is currently unknown, which hinders effective control. The purpose of this study was to characterize the prevalence and intensity of infection of S. mansoni in a remote area of western Tanzania. METHODOLOGY/PRINCIPAL FINDINGS: Stool samples were collected from 192 children and 147 adults residing in Gombe National Park and four nearby villages. Children were actively sampled in local schools, and adults were sampled passively by voluntary presentation at the local health clinics. The two datasets were therefore analysed separately. Faecal worm egg count (FWEC) data were analysed using negative binomial and zero-inflated negative binomial (ZINB) models with explanatory variables of site, sex, and age. The ZINB models indicated that a substantial proportion of the observed zero FWEC reflected a failure to detect eggs in truly infected individuals, meaning that the estimated true prevalence was much higher than the apparent prevalence as calculated based on the simple proportion of non-zero FWEC. For the passively sampled data from adults, the data were consistent with close to 100% true prevalence of infection. Both the prevalence and intensity of infection differed significantly between sites, but there were no significant associations with sex or age. CONCLUSIONS/SIGNIFICANCE: Overall, our data suggest a more widespread distribution of S. mansoni in this part of Tanzania than was previously thought. The apparent prevalence estimates substantially under-estimated the true prevalence as determined by the ZINB models, and the two types of sampling strategies also resulted in differing conclusions regarding prevalence of infection. We therefore recommend that future surveillance programmes designed to assess risk factors should use active sampling whenever possible, in order to avoid the self-selection bias associated with passive sampling.

Assessment of schistosomiasis and soil-transmitted helminths prevalence in school-aged children and opportunities for integration of control in local health services in Kwilu Province, the Democratic Republic of the Congo.

OBJECTIVE: To determine the prevalence of schistosomiasis (SCH) and soil-transmitted helminths (STH) in the Democratic Republic of Congo, and to assess the capacity of the local health centres for diagnosis and treatment. METHODS: Cross-sectional school-based survey in two health districts in the Province of Kwilu. We collected a stool and a urine sample for parasitological examination. Urine filtration and duplicate Kato-Katz thick smears were used for the diagnosis of SCH. Health centres were evaluated using a structured questionnaire. RESULTS: In total, 526 children participated in the study and the overall prevalence of Schistosoma mansoni infection was 8.9% (95% CI: 3.5-13.2) in both districts. The prevalence was higher in Mosango (11.7%; 95% CI: 8.9-14.8) than Yasa Bonga district (6.2%; 95% CI: 1.1-11.4). Urine filtration showed that Schistosoma haematobium infection was not present. The combined STH infection prevalence was 58.1% in both districts; hookworm infection was the most common STH found in 52.9% (95% CI: 29.3-62.4) of subjects, followed by Ascaris lumbricoides 9.3% (95% CI: 5.8-15.5) and Trichuris trichiura 2.1% (95% CI: 0.9-4.9). Mixed STH infections were observed as well as SCH-STH coinfection. CONCLUSION: Further mapping of both SCH and STH burden is needed, and coverage of preventive chemotherapy in school-aged children should be increased.