Antibody response to malaria vaccine candidates in pregnant women with Plasmodium falciparum and Schistosoma haematobium infections.

Malaria in pregnancy has severe consequences for the mother and foetus. Antibody response to specific malaria vaccine candidates (MVC) has been associated with a decreased risk of clinical malaria and its outcomes. We studied Plasmodium falciparum (Pf) and Schistosoma haematobium (Sh) infections and factors that could influence antibody responses to MVC in pregnant women. A total of 337 pregnant women receiving antenatal care (ANC) and 139 for delivery participated in this study. Pf infection was detected by qPCR and Sh infection using urine filtration method. Antibody levels against CSP, AMA-1, GLURP-R0, VAR2CSA and Pfs48/45 MVC were quantified by ELISA. Multivariable linear regression models identified factors associated with the modulation of antibody responses. The prevalence of Pf and Sh infections was 27% and 4% at ANC and 7% and 4% at delivery. Pf infection, residing in Adidome and multigravidae were positively associated with specific IgG response to CSP, AMA-1, GLURP-R0 and VAR2CSA. ITN use and IPTp were negatively associated with specific IgG response to GLURP-R0 and Pfs48/45. There was no association between Sh infection and antibody response to MVC at ANC or delivery. Pf infections in pregnant women were positively associated with antibody response to CSP, GLURP-R0 and AMA-1. Antibody response to GLURP-R0 and Pfs48/45 was low for IPTp and ITN users. This could indicate a lower exposure to Pf infection and low malaria prevalence observed at delivery.

The long road to schistosomiasis elimination in Zanzibar: A systematic review covering 100 years of research, interventions and control milestones.

Zanzibar is among the few places in sub-Saharan Africa where interruption of Schistosoma transmission seems an achievable goal. Our systematic review identifies and discusses milestones in schistosomiasis research, control and elimination efforts in Zanzibar over the past 100 years. The search in online databases, libraries, and the World Health Organization Archives revealed 153 records published between May 1928 and August 2022. The content of records was summarised to highlight the pivotal work leading towards urogenital schistosomiasis elimination and remaining research gaps. The greatest achievement following 100 years of schistosomiasis interventions and research is undoubtedly the improved health of Zanzibaris, exemplified by the reduction in Schistosoma haematobium prevalence from>50% historically down to<5% in 2020, and the absence of severe morbidities. Experiences from Zanzibar have contributed to global schistosomiasis guidelines, whilst also revealing challenges that impede progression towards elimination. Challenges include: transmission heterogeneity requiring micro-targeting of interventions, post-treatment recrudescence of infections in transmission hotspots, biological complexity of intermediate host snails, emergence of livestock Schistosoma species complicating surveillance whilst creating the risk for interspecies hybridisation, insufficient diagnostics performance for light intensity infections and female genital schistosomiasis, and a lack of acceptable sanitary alternatives to freshwater bodies. Our analysis of the past revealed that much can be achieved in the future with practical implementation of integrated interventions, alongside operational research. With continuing national and international commitments, interruption of S. haematobium transmission across both islands is within reach by 2030, signposting the future demise of urogenital schistosomiasis across other parts of sub-Saharan Africa.

Urinogenital schistosomiasis knowledge, attitude, practices, and its clinical correlates among communities along water bodies in the Kwahu Afram Plains North District, Ghana.

BACKGROUND: Adequate knowledge and proper practices coupled with knowledge of the burden of disease are necessary for the eradication of Schistosoma infection. This study assessed knowledge, attitude, and practice (KAP) as well as health outcomes related to Schistosoma haematobium infection at Kwahu Afram Plains North District (KAPND). METHODS: A cross-sectional survey using a structured questionnaire was carried out among 140 participants from four local communities in KAPND in August 2021. From these participants, 10ml of urine was collected for determination of the presence of S. haematobium and urine routine examination. In addition, 4ml of blood was collected and used for haematological examination. Descriptive statistics and logistic regression analysis using IBM SPSS were used to describe and represent the data collected. RESULTS: The study reports a gap in knowledge about schistosomiasis in the study area with the majority indicating that they have not heard of schistosomiasis (60.7%), do not know the mode of transmission (49.3%), and do not know how the disease could be spread (51.5%). The overall prevalence of urinary schistosomiasis was 52.9%. This was associated with age, occupation, perceived mode of Schistosoma transmission, knowledge of Schistosoma prevention, awareness that schistosomiasis can be treated, frequency of visits to water bodies, and water usage patterns. In multivariate analysis, factors that remained significantly associated with S. haematobium infection were age 21-40 (OR = 0.21, 95% CI: 0.06-0.76), 41-60 (OR = 0.01, 95% CI: 0.01-0.52) and ≥ 60 (OR = 0.02, 95% CI: 0.02-0.87), informal employment (OR = 0.01, 95% CI: 0.01-0.69) and awareness of transmission by drinking water from river body (OR = 0.03, 95% CI: 0.03-0.92). In Schistosoma infection, reduced haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, lymphocytes and eosinophils were observed. White blood cells, neutrophils, and monocytes were significantly elevated in infected states. Urine analysis revealed high pus cells and red blood cells counts among Schistosoma-positive participants. CONCLUSION: Schistosoma infection is endemic among inhabitants in KAPND, and is associated with a gap in knowledge, awareness, and practice possibly due to inadequate education in the area. Poor clinical outcomes associated with Schistosoma infection have been demonstrated in the area. A well-structured public education, nutritional intervention, and mass drug administration will be necessary to eradicate this menace.

Prevalence and risk distribution of schistosomiasis among adults in Madagascar: a cross-sectional study.

BACKGROUND: The goal to eliminate the parasitic disease of poverty schistosomiasis as a public health problem is aligned with the 2030 United Nations agenda for sustainable development goals, including universal health coverage (UHC). Current control strategies focus on school-aged children, systematically neglecting adults. We aimed at providing evidence for the need of shifting the paradigm of schistosomiasis control programs from targeted to generalized approaches as key element for both the elimination of schistosomiasis as a public health problem and the promotion of UHC. METHODS: In a cross-sectional study performed between March 2020 and January 2021 at three primary health care centers in Andina, Tsiroanomandidy and Ankazomborona in Madagascar, we determined prevalence and risk factors for schistosomiasis by a semi-quantitative PCR assay from specimens collected from 1482 adult participants. Univariable and multivariable logistic regression were performed to evaluate odd ratios. RESULTS: The highest prevalence of S. mansoni, S. haematobium and co-infection of both species was 59.5%, 61.3% and 3.3%, in Andina and Ankazomborona respectively. Higher prevalence was observed among males (52.4%) and main contributors to the family income (68.1%). Not working as a farmer and higher age were found to be protective factors for infection. CONCLUSIONS: Our findings provide evidence that adults are a high-risk group for schistosomiasis. Our data suggests that, for ensuring basic health as a human right, current public health strategies for schistosomiasis prevention and control need to be re-addressed towards more context specific, holistic and integrated approaches.

Knowledge and factors influencing schistosomiasis control interventions in the hyperendemic health district of Kalabancoro in Mali, 2020.

Introduction: schistosomiasis is a public health concerns in many countries including Mali. In Kalabancoro District, during the 2017 assessments, the National schistosomiasis and soil-transmitted helminths control program reported prevalence´s of 10.83% and 50.83% for urinary schistosomiasis and intestinal schistosomiasis respectively. This district recorded the highest prevalence of intestinal schistosomiasis among the 46 districts evaluated. To better understand these high rates, this study investigated the knowledge of schistosomiasis in children and adults in this district. Methods: a cross-sectional study was conducted which involved 947 participants. A univariate analysis and multiple logistic regression were performed. Data collection was through questionnaire administration. Results: during the study, 76.1% of participants claimed to know about schistosomiasis (p<0.001) among them, 85.6% did not know the mode of contamination (p=0.001) and 66.3% knew the traditional treatment (p=0.004). Participants whose households were close to water impoundment were 2.16 times more likely to know schistosomiasis than those who were not (95% CI = [1.49 - 3.11]). Conclusion: most of the majority of participants reported being aware of schistosomiasis. However, the modes of transmission, prevention, and treatment of schistosomiasis were not well known. Misconceptions persist, hindering effective prevention and control. This is a tangible obstacle to the elimination of schistosomiasis in the Kalabancoro Health District and requires interventions tailored for these endemic communities.

Healthcare Workers' Low Knowledge of Female Genital Schistosomiasis and Proposed Interventions to Prevent, Control, and Manage the Disease in Zanzibar.

Objectives: This study was conducted to explore healthcare workers' knowledge of female genital schistosomiasis (FGS) and describe proposed interventions to raise awareness about FGS and strengthen healthcare facilities' capacity to manage FGS cases. Methods: We conducted four cross-sectional focus group discussions and 16 key informant interviews with purposively selected healthcare workers in Zanzibar. Discussions and interviews were digitally recorded, transcribed, and analyzed using NVivo software. Results: Most participants had limited or no knowledge of FGS and lacked skills for managing it. They confused FGS with urogenital schistosomiasis and thought it was sexually transmitted. A few participants knew about FGS and associated it with Human Immunodeficiency Virus (HIV), ectopic pregnancy, cervical cancer, and infertility. To prevent and control FGS, participants proposed interventions targeting communities (including community-based health education) and the healthcare system (including training healthcare workers on FGS). Conclusion: Healthcare workers lacked knowledge of and skills for managing FGS. Besides, healthcare facilities had no diagnostic capacity to manage FGS. Along with on-going interventions to break S. haematobium transmission and eventually eliminate urogenital schistosomiasis in Zanzibar, we recommend training healthcare workers on FGS and equip healthcare facilities with medical equipment and supplies for managing FGS.

Potential drivers for schistosomiasis persistence: Population genetic analyses from a cluster-randomized urogenital schistosomiasis elimination trial across the Zanzibar islands.

The World Health Organization's revised NTD Roadmap and the newly launched Guidelines target elimination of schistosomiasis as a public health problem in all endemic areas by 2030. Key to meeting this goal is elucidating how selective pressures imposed by interventions shape parasite populations. Our aim was to identify any differential impact of a unique cluster-randomized tri-armed elimination intervention (biannual mass drug administration (MDA) applied alone or in association with either mollusciciding (snail control) or behavioural change interventions) across two Zanzibarian islands (Pemba and Unguja) on the population genetic composition of Schistosoma haematobium over space and time. Fifteen microsatellite loci were used to analyse individual miracidia collected from infected individuals across islands and intervention arms at the start (2012 baseline: 1,522 miracidia from 176 children; 303 from 43 adults; age-range 6-75, mean 12.7 years) and at year 5 (2016: 1,486 miracidia from 146 children; 214 from 25 adults; age-range 9-46, mean 12.4 years). Measures of genetic diversity included allelic richness (Ar), Expected (He) and Observed heterozygosity (Ho), inbreeding coefficient (FST), parentage analysis, estimated worm burden, worm fecundity, and genetic sub-structuring. There was little evidence of differential selective pressures on population genetic diversity, inbreeding or estimated worm burdens by treatment arm, with only the MDA+snail control arm within Unguja showing trends towards reduced diversity and altered inbreeding over time. The greatest differences overall, both in terms of parasite fecundity and genetic sub-structuring, were observed between the islands, consistent with Pemba's persistently higher mean infection intensities compared to neighbouring Unguja, and within islands in terms of infection hotspots (across three definitions). These findings highlight the important contribution of population genetic analyses to elucidate extensive genetic diversity and biological drivers, including potential gene-environmental factors, that may override short term selective pressures imposed by differential disease control strategies. Trial Registration: ClinicalTrials.gov ISRCTN48837681.

Prevalence and factors associated with persistent transmission of Schistosoma haematobium among primary school children after five rounds of mass drug administration using praziquantel: A cross sectional study in Mkuranga district, Tanzania.

Despite a human schistosomiasis control programme through praziquantel mass drug administration (MDA) between 2011 and 2015,there was still persistent transmission among primary schoolchildren (PSC) in Mkuranga district, Tanzania. Our cross-sectional study was conducted among 396 PSC who provided urine for diagnosis of Schistosoma haematobium infection. Observations were conducted to determine PSC water contact activities. Logistic regression was used to test association between dependent and independent variables. We found MDA uptake among PSC as 72.5%, and the prevalence of Schistosoma haematobium infection 5.8%. The risk of infection increased among PSC engaged in fetching water and adjusted odds ratio (AOR) for swimming, bathing, fishing, crossing ponds and paddy fields were 0.123, 0.166, 0.232, 0.202 and 0.093 respectively. Thus we conclude that multiple water contact activities and low participation in MDA is responsible for persistent Schistosoma transmission.

Fine-scale-mapping of Schistosoma haematobium infections at the school and community levels and intermediate host snail abundance in the north of Pemba Island: baseline cross-sectional survey findings before the onset of a 3-year intervention study.

BACKGROUND: Schistosomiasis elimination has gained renewed priority in the WHO guidance documents published in 2020 and 2022. The SchistoBreak project, implemented in Pemba, Tanzania between 2020 and 2024, aims to assess new tools and strategies for shifting from elimination as a public health problem towards interruption of transmission. Here we report our baseline findings and discuss implications for future interventions. METHODS: In 2020, human water contact sites (HWCSs) in the study area were geolocated and snail surveys were conducted. A parasitological and questionnaire cross-sectional baseline survey was implemented in 20 communities and their 16 primary schools between November 2020 and February 2021. Urine samples were collected at the school and household levels from individuals aged ≥ 4 years. Schistosoma haematobium infection was detected by urine filtration microscopy. Snail, parasitological and questionnaire-derived data were analyzed descriptively, spatially and with generalized estimated equation models. RESULTS: The intermediate host snail Bulinus globosus was detected in 19.8% (33/167) of HWCSs. The overall S. haematobium prevalence was 1.2% (26/2196) in school-aged children and 0.8% (31/3893) in community members, with 0.2% (4/2196) and 0.1% (3/3893) heavy-intensity infections, respectively. Children who studied < 1 km away from HWCSs with B. globosus had significantly higher odds for a S. haematobium infection than those attending a school located > 2 km away (odds ratio [OR]: 5.0; 95% confidence interval [CI]: 2.3-11.1). Individuals living in a house located < 1 km away from HWCSs with B. globosus had higher odds than those residing in > 2 km distance (OR: 18.0; 95% CI: 2.9-111.0). Self-reported praziquantel treatment coverage was 83.2% (2015/2423) in schoolchildren in the mass drug administration (MDA) conducted in August 2020. Coverage among adult community members was 59.9% (574/958), but only 34.8% (333/958) took praziquantel correctly. CONCLUSIONS: While the S. haematobium prevalence is very low in Pemba, there are many HWCSs with B. globosus situated close to schools or houses that pose a considerable risk of recrudescence. To maintain and accelerate the progress towards interruption of transmission, targeted and cost-effective interventions that are accepted by the community are needed; for example, snail control plus focal MDA, or test-and-treat in schools and households near infested waterbodies.

Prevalence and risk factors of urogenital schistosomiasis among under-fives in Mtama District in the Lindi region of Tanzania.

INTRODUCTION: Despite the ongoing intervention for schistosomiasis control among school-age children in the Lindi region of Tanzania, urogenital schistosomiasis continues to be a public health problem, presumably because other at-risk populations are not covered in praziquantel deworming campaigns. Evidence shows that under-fives become infected in their early life hence the need to understand the disease profile and the risk factors for exposure to infection so as to plan effective control strategies in this group. This study examined the prevalence and risk factors of urogenital schistosomiasis among under-fives in the Mtama district, Lindi region of Tanzania. METHODOLOGY/PRINCIPAL FINDINGS: A quantitative community-based cross-sectional study was carried out among 770 participants (385 under-fives and their 385 parents/guardians) in the Mtama district to investigate the burden and the risk factors associated with S. haematobium infection. A single urine specimen was collected from the under-fives and tested for macro and microhaematuria, presence of S. haematobium ova, and intensity of infection. A structured questionnaire gathered on risk factors for S. haematobium exposure in under-fives from their parents/guardians. Data analysis was performed using descriptive statistics, chi-square test, and logistic regression. Prevalence of S. haematobium ova was 16.9%, and that of macro and microhaematuria was 6% and 17.9%, respectively. Of the 65 positive under-fives, 49 (75.4%) 95% CI 65.4-86.3 had a light infection intensity, and 16 (24.6%) 95% CI 13.7-35.5 had a heavy infection intensity. Among the assessed risk factors, the parents/guardians habit of visiting water bodies for domestic routines (AOR: 1.44, 95% CI: 1.13-1.74), especially the river (AOR: 6.00, 95% CI: 1.20-35.12), was found to be a significant risk factor for infection of S. haematobium in under-fives. CONCLUSION/SIGNIFICANCE: A moderate prevalence of S. haematobium was found among the under-fives conceivably with adverse health events. The infected under-fives could be a source of continuity for transmission in the community. An intervention that covers this group is necessary and should be complemented with regular screening, health education campaigns, and an adequate supply of safe water.

Discovery of a Hidden Schistosomiasis Endemic in the Salamat Region of Chad, Africa.

There is currently a severe paucity of rural epidemiologic data on urogenital schistosomiasis in the Republic of Chad in north-central Africa that is hindering national control strategies. Our study describes a mobile medical team's 4-year effort to collect data and provide mass therapeutic and preventive chemotherapy in the Salamat Region of Chad, a previously uninvestigated rural area. To overcome severe limitations in time, resources, support, and infrastructure, the team employed several time- and cost-saving techniques that included: (1) traveling by request and referral to utilize local knowledge to find the areas of highest need, (2) conducting convenience sampling for screening, (3) using simple but validated tools to expedite treatment and data gathering, and (4) working within cultural contexts to find and treat the most school-age children possible. The team managed a total of 11,832 patient encounters and found a 55% rate of hematuria (n=6,495) among school-age children, roughly double previous estimates. Rates of hematuria were higher in males (61%, n=3,955/6,466) than females (48%, n=2,301/4,806) and among adolescents (> 65% in all age groups aged 10 years and older). These methods outline an efficient and effective strategy implemented under real-world conditions to enact therapeutic and preventive chemotherapy campaigns in resource-limited settings by engaging village leadership and developing locally driven solutions. Our data highlight the need for continued local epidemiologic efforts to treat the substantial number of children severely affected with schistosomiasis.

GPS-based fine-scale mapping surveys for schistosomiasis assessment: a practical introduction and documentation of field implementation.

BACKGROUND: Fine-scale mapping of schistosomiasis to guide micro-targeting of interventions will gain importance in elimination settings, where the heterogeneity of transmission is often pronounced. Novel mobile applications offer new opportunities for disease mapping. We provide a practical introduction and documentation of the strengths and shortcomings of GPS-based household identification and participant recruitment using tablet-based applications for fine-scale schistosomiasis mapping at sub-district level in a remote area in Pemba, Tanzania. METHODS: A community-based household survey for urogenital schistosomiasis assessment was conducted from November 2020 until February 2021 in 20 small administrative areas in Pemba. For the survey, 1400 housing structures were prospectively and randomly selected from shapefile data. To identify pre-selected structures and collect survey-related data, field enumerators searched for the houses' geolocation using the mobile applications Open Data Kit (ODK) and MAPS.ME. The number of inhabited and uninhabited structures, the median distance between the pre-selected and recorded locations, and the dropout rates due to non-participation or non-submission of urine samples of sufficient volume for schistosomiasis testing was assessed. RESULTS: Among the 1400 randomly selected housing structures, 1396 (99.7%) were identified by the enumerators. The median distance between the pre-selected and recorded structures was 5.4 m. A total of 1098 (78.7%) were residential houses. Among them, 99 (9.0%) were dropped due to continuous absence of residents and 40 (3.6%) households refused to participate. In 797 (83.1%) among the 959 participating households, all eligible household members or all but one provided a urine sample of sufficient volume. CONCLUSIONS: The fine-scale mapping approach using a combination of ODK and an offline navigation application installed on tablet computers allows a very precise identification of housing structures. Dropouts due to non-residential housing structures, absence, non-participation and lack of urine need to be considered in survey designs. Our findings can guide the planning and implementation of future household-based mapping or longitudinal surveys and thus support micro-targeting and follow-up of interventions for schistosomiasis control and elimination in remote areas. Trial registration ISRCTN, ISCRCTN91431493. Registered 11 February 2020, https://www.isrctn.com/ISRCTN91431493.

Effectiveness of Four Different Interventions Against Schistosoma haematobium in a Seasonal Transmission Setting of Côte d'Ivoire: A Cluster Randomized Trial.

BACKGROUND: Annual mass drug administration (MDA) using praziquantel is the cornerstone of schistosomiasis morbidity control but is not sufficient to interrupt transmission. We implemented a cluster-randomized trial to compare the effectiveness of 4 different intervention packages to interrupt transmission of Schistosoma haematobium in a seasonal transmission setting of Côte d'Ivoire. METHODS: Sixty-four localities with a S. haematobium prevalence in school children aged 13-14 years above 4% were randomly assigned to 1 of 4 intervention arms over a 3-year period: (1) the current standard strategy consisting of annual MDA before peak of transmission, (2) annual MDA after peak of transmission, (3) biannual MDA, and (4) standard MDA combined with snail control. The primary outcome was prevalence and intensity of S. haematobium infection in children aged 9-12 years 1 year after the final intervention, using urine filtration performed by experienced microscopists. RESULTS: By study end, we observed the lowest S. haematobium prevalence in the biannual MDA, compared to the standard treatment arm (0.6% vs 7.5%; odds ratio [OR] = 0.07, 95% confidence interval [CI] = .02 to .24). The prevalence in arms 2 and 4 was about 3.5%, which was not statistically significantly different from the standard strategy (both ORs 0.4, 95% CI = .1 to ~1.8). New cases of infection were still observed in all arms at study end. CONCLUSIONS: Biannual MDA was the only regimen that outperformed the standard treatment. All strategies resulted in decreased prevalence of infection; however, none of them was able to interrupt transmission of S. haematobium within a 3-year period. CLINICAL TRIALS REGISTRATION: ISRCTN10926858.

Immunomics-Guided Antigen Discovery for Praziquantel-Induced Vaccination in Urogenital Human Schistosomiasis.

Despite the enormous morbidity attributed to schistosomiasis, there is still no vaccine to combat the disease for the hundreds of millions of infected people. The anthelmintic drug, praziquantel, is the mainstay treatment option, although its molecular mechanism of action remains poorly defined. Praziquantel treatment damages the outermost surface of the parasite, the tegument, liberating surface antigens from dying worms that invoke a robust immune response which in some subjects results in immunologic resistance to reinfection. Herein we term this phenomenon Drug-Induced Vaccination (DIV). To identify the antigenic targets of DIV antibodies in urogenital schistosomiasis, we constructed a recombinant proteome array consisting of approximately 1,000 proteins informed by various secretome datasets including validated proteomes and bioinformatic predictions. Arrays were screened with sera from human subjects treated with praziquantel and shown 18 months later to be either reinfected (chronically infected subjects, CI) or resistant to reinfection (DIV). IgG responses to numerous antigens were significantly elevated in DIV compared to CI subjects, and indeed IgG responses to some antigens were completely undetectable in CI subjects but robustly recognized by DIV subjects. One antigen in particular, a cystatin cysteine protease inhibitor stood out as a unique target of DIV IgG, so recombinant cystatin was produced, and its vaccine efficacy assessed in a heterologous Schistosoma mansoni mouse challenge model. While there was no significant impact of vaccination with adjuvanted cystatin on adult worm numbers, highly significant reductions in liver egg burdens (45-55%, P<0.0001) and intestinal egg burdens (50-54%, P<0.0003) were achieved in mice vaccinated with cystatin in two independent trials. This study has revealed numerous antigens that are targets of DIV antibodies in urogenital schistosomiasis and offer promise as subunit vaccine targets for a drug-linked vaccination approach to controlling schistosomiasis.

Prevalence and risk factors of schistosomiasis among primary school children in four selected regions of The Gambia.

BACKGROUND: The Gambia initiated a control programme for schistosomiasis in 2015. In light of this, recent and comprehensive data on schistosomiasis is required to effectively guide the control programme. This study aimed to evaluate the prevalence and associated risk factors of schistosomiasis among primary school children in The Gambia. METHODS: We utilised data from a previous study conducted in 2015 in 4 regions of The Gambia: North Bank Region (NBR), Lower River Region (LRR), Central River Region (CRR) and Upper River Region (URR). In the parent study, ten schools were selected randomly from each region. Urine and stool samples collected from 25 boys and 25 girls (7-14 years) in each school were examined for urinary schistosomiasis (Schistosoma haematobium infection) and intestinal schistosomiasis (Schistosoma mansoni infection) using urine filtration, dipstick and Kato-Katz methods. PRINCIPAL FINDINGS: Urinary schistosomiasis had an overall prevalence of 10.2% while intestinal schistosomiasis had a prevalence of 0.3% among the sampled school children. Prevalence of urinary schistosomiasis was significantly different among regions (χ 2 = 279.958, df = 3, p < 0.001), with CRR (27.6%) being the most endemic region, followed by URR (12.0%), then LRR (0.6%), and NBR (0.0%). Prevalence of intestinal schistosomiasis was also significantly variable among regions, with 4 of the 5 positive cases detected in CRR and 1 case in URR. Every school sampled in CRR had at least one student infected with S. haematobium, 50% of schools in URR had S. haematobium infection, and just one school in LRR had S. haematobium infection. While S. haematobium infection was significantly higher in boys (χ 2 = 4.440, df = 1, p = 0.035), no significant difference in infection rate was observed among age groups (χ 2 = 0.882, df = 2, p = 0.643). Two of the 5 students infected with S. mansoni were boys and 3 were girls. Four of these 5 students were in the 10-12 years age group and 1 was in the 7-9 years age group. Macrohaematuria and microhaematuria were found to be statistically associated with presence of S. haematobium eggs in urine. Being a male was a risk factor of S. haematobium infection. Bathing, playing and swimming in water bodies were found to pose less risk for S. haematobium infection, indicating that the true water contact behaviour of children was possibly underrepresented. CONCLUSION: The findings of this study provide invaluable information on the prevalence of schistosomiasis in The Gambia. This was useful for the schistosomiasis control efforts of the country, as it guided mass drug administration campaigns in eligible districts in the study area. More studies on S. mansoni and its intermediate snail hosts are required to establish its true status in The Gambia. As children sometimes tend to provide responses that potentially please the research or their teacher, data collection frameworks and approaches that ensure true responses in studies involving children should be devised and used.

Mapping Schistosoma haematobium for Novel Interventions against Female Genital Schistosomiasis and Associated HIV Risk in KwaZulu-Natal, South Africa.

Women with female genital schistosomiasis (FGS) have been found to have genital symptoms and a three-fold higher risk of HIV infection. Despite WHO recommendations, regular antischistosomal mass drug administration (MDA) has not yet been implemented in South Africa possibly because of the lack of updated epidemiological data. To provide data for future prevention efforts against FGS and HIV, this study explored Schistosoma haematobium prevalence in girls and young women and the effects of antischistosomal MDA, respectively. Urinary schistosomiasis and genital symptoms were investigated in 70 randomly selected secondary schools in three districts within KwaZulu-Natal and 18 primary schools. All study participants were treated for schistosomiasis, and schools with the highest urinary prevalence were followed up after 1 and 4 years of MDA. At baseline, urine analysis data showed that most schools were within the moderate-risk prevalence category where biennial antischistosomal MDA is recommended, as per WHO guidelines. Young women had high prevalence of genital symptoms (36%) after correcting for sexually transmitted infections. These symptoms may be caused by infection with schistosomes. However, FGS cannot be diagnosed by urine analysis alone. In KwaZulu-Natal rural schools, this study suggests that antischistosomal MDA with praziquantel could prevent genital symptoms in more than 200,000 young women. Furthermore, it is feasible that more than 5,000 HIV infections could be prevented in adolescent girls and young women by treatment and prevention of FGS.

A cross-sectional survey of the knowledge, attitudes and practices regarding schistosomiasis among rural schoolchildren in Taiz governorate, southwestern Yemen.

BACKGROUND: This cross-sectional survey aimed to assess the knowledge, attitudes and practices (KAP) towards schistosomiasis among rural schoolchildren in Taiz governorate, southwestern Yemen. METHODS: A total of 406 children were screened for urogenital and intestinal schistosomiasis. A pretested questionnaire was used to collect the children's demographic and socio-economic information and their KAP towards schistosomiasis. RESULTS: Overall, 73 children (18%) were found to be infected by Schistosoma mansoni. None of the children were positive for Schistosoma haematobium. The prevalence of intestinal schistosomiasis was significantly higher among boys than girls (22.1% vs 12%; p=0.010). Approximately two-thirds (63.3% [257/406]) of the children had heard about schistosomiasis, however, only 38.5%, 53.6%, 28.4% and 38.1% had correct knowledge concerning the causes, symptoms, transmission and prevention, respectively. A significantly higher level of knowledge was observed among boys and Schistosoma-infected children compared with girls and non-infected children (p<0.05). However, a better level of knowledge does not seem to translate directly into the performance of hygienic practices. Multivariate logistic regression showed that sex and infection status were the significant predictors of good knowledge. CONCLUSIONS: Intestinal schistosomiasis is prevalent among schoolchildren in rural Yemen. The findings reveal that children's knowledge about schistosomiasis is inadequate. Therefore, besides mass drug administration, integrated control programmes should also include health education and the provision of improved drinking water and proper sanitation.

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.

The impact of mass drug administration on Schistosoma haematobium infection: what is required to achieve morbidity control and elimination?

BACKGROUND: Schistosomiasis remains an endemic parasitic disease causing much morbidity and, in some cases, mortality. The World Health Organization (WHO) has outlined strategies and goals to combat the burden of disease caused by schistosomiasis. The first goal is morbidity control, which is defined by achieving less than 5% prevalence of heavy intensity infection in school-aged children (SAC). The second goal is elimination as a public health problem (EPHP), achieved when the prevalence of heavy intensity infection in SAC is reduced to less than 1%. Mass drug administration (MDA) of praziquantel is the main strategy for control. However, there is limited availability of praziquantel, particularly in Africa where there is high prevalence of infection. It is therefore important to explore whether the WHO goals can be achieved using the current guidelines for treatment based on targeting SAC and, in some cases, adults. Previous modelling work has largely focused on Schistosoma mansoni, which in advance cases can cause liver and spleen enlargement. There has been much less modelling of the transmission of Schistosoma haematobium, which in severe cases can cause kidney damage and bladder cancer. This lack of modelling has largely been driven by limited data availability and challenges in interpreting these data. RESULTS: In this paper, using an individual-based stochastic model and age-intensity profiles of S. haematobium from two different communities, we calculate the probability of achieving the morbidity and EPHP goals within 15 years of treatment under the current WHO treatment guidelines. We find that targeting SAC only can achieve the morbidity goal for all transmission settings, regardless of the burden of infection in adults. The EPHP goal can be achieved in low transmission settings, but in some moderate to high settings community-wide treatment is needed. CONCLUSIONS: We show that the key determinants of achieving the WHO goals are the precise form of the age-intensity of infection profile and the baseline SAC prevalence. Additionally, we find that the higher the burden of infection in adults, the higher the chances that adults need to be included in the treatment programme to achieve EPHP.

Evaluating the impact of biannual school-based and community-wide treatment on urogenital schistosomiasis in Niger.

BACKGROUND: The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) coordinated a five-year study implemented in several countries, including Niger, to provide an evidence-base for programmatic decisions regarding cost-effective approaches to preventive chemotherapy for schistosomiasis control. METHODS: This was a cluster-randomised trial investigating six possible combinations of annual or biannual community-wide treatment (CWT), school-based treatment (SBT), and holidays from mass treatment over four years. The most intense arm involved two years of annual CWT followed by 2 years of biannual CWT, while the least intensive arm involved one year of annual SBT followed by a year without treatment and two more years of annual SBT. The primary outcome of interest was prevalence and intensity of Schistosoma haematobium among 100 children aged 9-12 years sampled each year. In addition, 100 children aged 5-8 years in their first year of school and 50 adults (aged 20-55 years) were tested in the first and final fifth year of the study. RESULTS: In total, data were collected from 167,500 individuals across 225 villages in nine districts within the Niger River valley, Western Niger. Overall, the prevalence of S. haematobium decreased from baseline to Year 5 across all study arms. The relative reduction of prevalence was greater in biannual compared with annual treatment across all arms; however, the only significant difference was seen in areas with a high starting prevalence. Although adults were not targeted for treatment in SBT arms, a statistically significant decrease in prevalence among adults was seen in moderate prevalence areas receiving biannual (10.7% to 4.8%) SBT (P < 0.001). Adults tested in the annual SBT group also showed a decrease in prevalence between Year 1 and Year 5 (12.2% to 11.0%), but this difference was not significant. CONCLUSIONS: These findings are an important consideration for schistosomiasis control programmes that are considering elimination and support the idea that scaling up the frequency of treatment rounds, particularly in areas of low prevalence, will not eliminate schistosomiasis. Interestingly, the finding that prevalence decreased among adults in SBT arms suggests that transmission in the community can be reduced, even where only school children are being treated, which could have logistical and cost-saving implications for the national control programmes.