Nanobody-Based Immunosensor Detection Enhanced by Photocatalytic-Electrochemical Redox Cycling.

Detection of antigenic biomarkers present in trace amounts is of crucial importance for medical diagnosis. A parasitic disease, human toxocariasis, lacks an adequate diagnostic method despite its worldwide occurrence. The currently used serology tests may stay positive even years after a possibly unnoticed infection, whereas the direct detection of a re-infection or a still active infection remains a diagnostic challenge due to the low concentration of circulating parasitic antigens. We report a time-efficient sandwich immunosensor using small recombinant single-domain antibodies (nanobodies) derived from camelid heavy-chain antibodies specific to Toxocara canis antigens. An enhanced sensitivity to pg/mL levels is achieved by using a redox cycle consisting of a photocatalytic oxidation and electrochemical reduction steps. The photocatalytic oxidation is achieved by a photosensitizer generating singlet oxygen (1O2) that, in turn, readily reacts with p-nitrophenol enzymatically produced under alkaline conditions. The photooxidation produces benzoquinone that is electrochemically reduced to hydroquinone, generating an amperometric response. The light-driven process could be easily separated from the background, thus making amperometric detection more reliable. The proposed method for detection of the toxocariasis antigen marker shows superior performances compared to other detection schemes with the same nanobodies and outperforms by at least two orders of magnitude the assays based on regular antibodies, thus suggesting new opportunities for electrochemical immunoassays of challenging low levels of antigens.

Fast One-Step Ultrasensitive Detection of Toxocara canis Antigens by a Nanobody-Based Electrochemical Magnetosensor.

Human toxocariasis (HT) is a cosmopolitan zoonotic disease caused by the migration of the larval stage of the roundworm Toxocara canis. Current HT diagnostic methods do not discriminate between active and past infections. Here, we present a method to quantify Toxocara excretory/secretory antigen, aiming to identify active cases of HT. High specificity is achieved by employing nanobodies (Nbs), single domain antigen binding fragments from camelid heavy chain-only antibodies. High sensitivity is obtained by the design of an electrochemical magnetosensor with an amperometric read-out. Reliable detection of TES antigen at 10 and 30 pg/mL level was demonstrated in phosphate buffered saline and serum, respectively. Moreover, the assay showed no cross-reactivity with other nematode antigens. To our knowledge, this is the most sensitive method to quantify the TES antigen so far. It also has great potential to develop point of care diagnostic systems in other conditions where high sensitivity and specificity are required.

Barcoding hybrids: heterogeneous distribution of Schistosoma haematobium × Schistosoma bovis hybrids across the Senegal River Basin.

Hybridization events between Schistosoma species (Digenea, Platyhelminthes) are reported with increasing frequency, largely due to improved access to molecular tools. Nevertheless, little is known about the distribution and frequency of hybrid schistosomes in nature. Screening for hybrids on a large scale is complicated by the need for nuclear and mitochondrial sequence information, precluding a 'simple' barcoding approach. Here we aimed to determine and understand the spatiotemporal distribution of Schistosoma haematobium × Schistosoma bovis hybrids in the Senegal River Basin. From ten villages, distributed over the four main water basins, we genotyped a total of 1236 schistosome larvae collected from human urine samples using a partial mitochondrial cox1 fragment; a subset of 268 parasites was also genotyped using ITS rDNA. Hybrid schistosomes were unevenly distributed, with substantially higher numbers in villages bordering Lac de Guiers than in villages from the Lampsar River and the Middle Valley of the Senegal River. The frequency of hybrids per village was not linked with the prevalence of urinary schistosomiasis in that village. However, we did find a significant positive association between the frequency of hybrids per village and the prevalence of Schistosoma mansoni. We discuss the potential consequences of adopting a barcoding approach when studying hybrids in nature.

Diagnostic comparison of Baermann funnel, Koga agar plate culture and polymerase chain reaction for detection of human Strongyloides stercoralis infection in Maluku, Indonesia.

Human infection with the nematode Strongyloides stercoralis, which may have a life-threatening course, primarily occurs in tropical settings. Epidemiological data on the occurrence of strongyloidiasis are scarce, and microscopic stool-based detection methods are insensitive. Polymerase chain reaction (PCR) assays have been developed, yet conflicting results have been reported. Our goal was to determine whether there was diagnostic agreement between an in-house PCR and two microscopic techniques, the Baermann funnel (BM) and the Koga agar plate culture (KAP) for the detection of S. stercoralis in stool samples. Eighty ethanol-fixed stool samples stemming from a cross-sectional survey in Maluku, Indonesia, were purposefully selected for PCR analysis. The final sample size comprised four groups, each with 20 samples: group 1, positive for S. stercoralis on both BM and KAP; group 2, positive only by BM; group 3, positive only by KAP; and group 4, negative on both BM and KAP. A Strongyloides-specific PCR targeting the internal transcribed spacer 2 (ITS2) region was carried out in an Indonesian reference laboratory. The overall agreement between PCR and microscopy was 61% (49/80 samples), being highest in group 1 (15/20, 75%) and lowest in group 3 (9/20, 45%). PCR revealed eight additional S. stercoralis infections in group 4. Future studies should elucidate the 'true' infection status of samples that are negative by PCR, but positive upon microscopy. Taken together, there is a lack of agreement between microscopy and PCR results for the diagnosis of human S. stercoralis infection in Indonesia. ClinicalTrials.gov (identifier: NCT02105714).

Detecting hybridization in African schistosome species: does egg morphology complement molecular species identification?

Hybrid parasites may have an increased transmission potential and higher virulence compared to their parental species. Consequently, hybrid detection is critical for disease control. Previous crossing experiments showed that hybrid schistosome eggs have distinct morphotypes. We therefore compared the performance of egg morphology with molecular markers with regard to detecting hybridization in schistosomes. We studied the morphology of 303 terminal-spined eggs, originating from 19 individuals inhabiting a hybrid zone with natural crosses between the human parasite Schistosoma haematobium and the livestock parasite Schistosoma bovis in Senegal. The egg sizes showed a high variability and ranged between 92·4 and 176·4 µm in length and between 35·7 and 93·0 µm in width. No distinct morphotypes were found and all eggs resembled, to varying extent, the typical S. haematobium egg type. However, molecular analyses on the same eggs clearly showed the presence of two distinct partial mitochondrial cox1 profiles, namely S. bovis and S. haematobium, and only a single nuclear ITS rDNA profile (S. haematobium). Therefore, in these particular crosses, egg morphology appears not a good indicator of hybrid ancestry. We conclude by discussing strengths and limitations of molecular methods to detect hybrids in the context of high-throughput screening of field samples.

NEGLECTED TROPICAL DISEASES IN BIOSOCIAL PERSPECTIVE.

The term 'neglected tropical diseases' (NTDs) points to the need for a biosocial perspective. Although 'diseases' are widely understood as biological phenomena, 'neglect' is inherently social. Social priorities, social relations and social behaviour profoundly influence the design, implementation and evaluation of control programmes. Yet, these dimensions of neglect are, themselves, neglected. Instead, emphasis is being placed on preventive chemotherapy - a technical, context-free approach which relies almost entirely on the mass distribution of drugs, at regular intervals, to populations living in endemic areas. This article reflects on the processes which have enabled an NTD 'brand' identity to emerge, and it comments on a disquieting disengagement with some of the more critical insights about the consequences of mass drug administration. Building on the work of biosocial scholars studying other aspects of health and disease, a more adequate, evidence-based approach is delineated. Developing such an approach is an iterative process, requiring on-going engagement with both biological and social insights as they emerge. Considerable theoretical, methodological and political challenges lie ahead, but it is essential they are overcome, if the sustainable control of NTDs is to become a reality.

Diagnosis of neglected tropical diseases among patients with persistent digestive disorders (diarrhoea and/or abdominal pain ≥14 days): Pierrea multi-country, prospective, non-experimental case-control study.

BACKGROUND: Diarrhoea still accounts for considerable mortality and morbidity worldwide. The highest burden is concentrated in tropical areas where populations lack access to clean water, adequate sanitation and hygiene. In contrast to acute diarrhoea (<14 days), the spectrum of pathogens that may give rise to persistent diarrhoea (≥14 days) and persistent abdominal pain is poorly understood. It is conceivable that pathogens causing neglected tropical diseases play a major role, but few studies investigated this issue. Clinical management and diagnostic work-up of persistent digestive disorders in the tropics therefore remain inadequate. Hence, important aspects regarding the pathogenesis, epidemiology, clinical symptomatology and treatment options for patients presenting with persistent diarrhoea and persistent abdominal pain should be investigated in multi-centric clinical studies. METHODS/DESIGN: This multi-country, prospective, non-experimental case-control study will assess persistent diarrhoea (≥14 days; in individuals aged ≥1 year) and persistent abdominal pain (≥14 days; in children/adolescents aged 1-18 years) in up to 2000 symptomatic patients and 2000 matched controls. Subjects from Côte d'Ivoire, Indonesia, Mali and Nepal will be clinically examined and interviewed using a detailed case report form. Additionally, each participant will provide a stool sample that will be examined using a suite of diagnostic methods (i.e., microscopic techniques, rapid diagnostic tests, stool culture and polymerase chain reaction) for the presence of bacterial and parasitic pathogens. Treatment will be offered to all infected participants and the clinical treatment response will be recorded. Data obtained will be utilised to develop patient-centred clinical algorithms that will be validated in primary health care centres in the four study countries in subsequent studies. DISCUSSION: Our research will deepen the understanding of the importance of persistent diarrhoea and related digestive disorders in the tropics. A diversity of intestinal pathogens will be assessed for potential associations with persistent diarrhoea and persistent abdominal pain. Different diagnostic methods will be compared, clinical symptoms investigated and diagnosis-treatment algorithms developed for validation in selected primary health care centres. The findings from this study will improve differential diagnosis and evidence-based clinical management of digestive syndromes in the tropics. TRIAL REGISTRATION: ClinicalTrials.gov; identifier: NCT02105714 .

Circulating antigen tests and urine reagent strips for diagnosis of active schistosomiasis in endemic areas.

BACKGROUND: Point-of-care (POC) tests for diagnosing schistosomiasis include tests based on circulating antigen detection and urine reagent strip tests. If they had sufficient diagnostic accuracy they could replace conventional microscopy as they provide a quicker answer and are easier to use. OBJECTIVES: To summarise the diagnostic accuracy of: a) urine reagent strip tests in detecting active Schistosoma haematobium infection, with microscopy as the reference standard; and b) circulating antigen tests for detecting active Schistosoma infection in geographical regions endemic for Schistosoma mansoni or S. haematobium or both, with microscopy as the reference standard. SEARCH METHODS: We searched the electronic databases MEDLINE, EMBASE, BIOSIS, MEDION, and Health Technology Assessment (HTA) without language restriction up to 30 June 2014. SELECTION CRITERIA: We included studies that used microscopy as the reference standard: for S. haematobium, microscopy of urine prepared by filtration, centrifugation, or sedimentation methods; and for S. mansoni, microscopy of stool by Kato-Katz thick smear. We included studies on participants residing in endemic areas only. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data, assessed quality of the data using QUADAS-2, and performed meta-analysis where appropriate. Using the variability of test thresholds, we used the hierarchical summary receiver operating characteristic (HSROC) model for all eligible tests (except the circulating cathodic antigen (CCA) POC for S. mansoni, where the bivariate random-effects model was more appropriate). We investigated heterogeneity, and carried out indirect comparisons where data were sufficient. Results for sensitivity and specificity are presented as percentages with 95% confidence intervals (CI). MAIN RESULTS: We included 90 studies; 88 from field settings in Africa. The median S. haematobium infection prevalence was 41% (range 1% to 89%) and 36% for S. mansoni (range 8% to 95%). Study design and conduct were poorly reported against current standards. Tests for S. haematobium Urine reagent test strips versus microscopyCompared to microscopy, the detection of microhaematuria on test strips had the highest sensitivity and specificity (sensitivity 75%, 95% CI 71% to 79%; specificity 87%, 95% CI 84% to 90%; 74 studies, 102,447 participants). For proteinuria, sensitivity was 61% and specificity was 82% (82,113 participants); and for leukocyturia, sensitivity was 58% and specificity 61% (1532 participants). However, the difference in overall test accuracy between the urine reagent strips for microhaematuria and proteinuria was not found to be different when we compared separate populations (P = 0.25), or when direct comparisons within the same individuals were performed (paired studies; P = 0.21).When tests were evaluated against the higher quality reference standard (when multiple samples were analysed), sensitivity was marginally lower for microhaematuria (71% vs 75%) and for proteinuria (49% vs 61%). The specificity of these tests was comparable. Antigen assayCompared to microscopy, the CCA test showed considerable heterogeneity; meta-analytic sensitivity estimate was 39%, 95% CI 6% to 73%; specificity 78%, 95% CI 55% to 100% (four studies, 901 participants). Tests for S. mansoni Compared to microscopy, the CCA test meta-analytic estimates for detecting S. mansoni at a single threshold of trace positive were: sensitivity 89% (95% CI 86% to 92%); and specificity 55% (95% CI 46% to 65%; 15 studies, 6091 participants) Against a higher quality reference standard, the sensitivity results were comparable (89% vs 88%) but specificity was higher (66% vs 55%). For the CAA test, sensitivity ranged from 47% to 94%, and specificity from 8% to 100% (4 studies, 1583 participants). AUTHORS' CONCLUSIONS: Among the evaluated tests for S. haematobium infection, microhaematuria correctly detected the largest proportions of infections and non-infections identified by microscopy.The CCA POC test for S. mansoni detects a very large proportion of infections identified by microscopy, but it misclassifies a large proportion of microscopy negatives as positives in endemic areas with a moderate to high prevalence of infection, possibly because the test is potentially more sensitive than microscopy.

Changes in immunological profile as a function of urbanization and lifestyle.

Differences in lifestyle and break with natural environment appear to be associated with changes in the immune system resulting in various adverse health effects. Although genetics can have a major impact on the immune system and disease susceptibility, the contribution of environmental factors is thought to be substantial. Here, we investigated the immunological profile of healthy volunteers living in a rural and an urban area of a developing African country (Senegal), and in a European country (the Netherlands). Using flow cytometry, we investigated T helper type 1 (Th1), Th2, Th17, Th22 and regulatory T cells, as well as CD4(+) T-cell and B-cell activation markers, and subsets of memory T and B cells in the peripheral blood. Rural Senegalese had significantly higher frequencies of Th1, Th2 and Th22 cells, memory CD4(+) T and B cells, as well as activated CD4(+) T and B cells compared with urban Senegalese and urban Dutch people. Within the Senegalese population, rural paritcipants displayed significantly higher frequencies of Th2 and Th22 cells, as well as higher pro-inflammatory and T-cell activation and memory profiles compared with the urban population. The greater magnitude of immune activation and the enlarged memory pool, together with Th2 polarization, seen in rural participants from Africa, followed by urban Africans and Europeans suggest that environmental changes may define immunological footprints, which could have consequences for disease patterns in general and vaccine responses in particular.

Impact of periodic selective mebendazole treatment on soil-transmitted helminth infections in Cuban schoolchildren.

OBJECTIVE: To evaluate the impact of periodic selective treatment with 500 mg mebendazole on soil-transmitted helminth (STH) infections in Cuban schoolchildren. METHODS: We followed up a cohort of 268 STH-positive schoolchildren, aged 5-14 years at baseline, at six-month intervals for two years and a final follow-up after three years. Kato-Katz stool examination was used to detect infections with Ascaris lumbricoides, Trichuris trichiura and hookworm. Common risk factors related to STHs were assessed by parental questionnaire. RESULTS: A significant reduction in the number of STH infections was obtained after three years with the highest reduction for T. trichiura (87.8%) and the lowest for hookworm (57.9%). After six months, cure rates (CRs) were 76.9% for A. lumbricoides, 67.4% for T. trichiura and 44.4% for hookworm. After two treatment rounds, more than 75% of all STH-positive children at baseline were cured, but with important differences between STH species (95.2% for A. lumbricoides, 80.5% for T. trichiura and 76.5% for hookworm). At the end of the study, these cumulative CRs were almost 100% for all three STHs. Risk factors for STHs were sex, sanitary disposal and habit of playing in the soil. CONCLUSIONS: Our results indicate that periodic selective treatment with 500 mg mebendazole is effective in reducing the number of STH infections in Cuban schoolchildren. Although important differences were found between helminth species, two rounds of treatment appeared sufficient to obtain substantial reductions.

T-helper 17 cells are associated with pathology in human schistosomiasis.

BACKGROUND: Schistosome infections are often clinically silent, but some individuals develop severe pathological reactions. In several disease processes, T-helper 17 (Th17) cells have been linked to tissue injuries, while regulatory T cells (Tregs) are thought to downmodulate inflammatory reactions. We assessed whether bladder pathology in human Schistosoma haematobium infection is related to the balance of Th17 cells and Tregs. We used a murine model of Schistosoma mansoni infection to further investigate whether the peripheral profiles reflected ongoing events in tissues. METHODS: We characterized T-helper cell subsets in the peripheral blood of children residing in a S. haematobium-endemic area and in the peripheral blood, spleen, and hepatic granulomas of S. mansoni-infected high-pathology CBA mice and low-pathology C57BL/6 mice. RESULTS: S. haematobium-infected children with bladder pathology had a significantly higher percentage of Th17 cells than those without pathology. Moreover, the Th17/Treg ratios were significantly higher in infected children with pathology, compared with infected children without pathology. Percentages of interleukin 17-producing cells were significantly higher in spleen and granulomas of CBA mice, compared with C57BL/6 mice. This difference was also reflected in the peripheral blood. CONCLUSIONS: This is the first study to indicate that Th17 cells may be involved in the pathogenesis of human schistosomiasis.

How are health systems in sub-Saharan Africa adapting to protect human health from climate change threats? A scoping review and case study.

BACKGROUND: Sub-Saharan Africa stands out as one of the regions most affected by the climate crisis, while it has contributed to the problem only marginally. The foreseen negative effect on health adds great stress to the already overburdened health systems. Health systems' adaptation to climate change is, therefore, urgently needed to better protect human health. There is, however, scant evidence on how adaption is being planned and implemented in Africa. The aim of this study was to review the literature on health system adaptation in sub-Saharan Africa. METHODS: In this scoping review and case study, we first carried out the scoping review, searching for publications on adaptation measures using the PubMed, Science Direct, and Web of Science databases on July 1, 2023. We included papers in English and French that addressed the adaptation of health systems in countries in sub-Saharan Africa without time limit. Second, we did a case study of the design and implementation of the National Adaptation Plan of Benin, with a specific focus on the policy-making process underlying the plan, whereby we used the health policy triangle as a policy analysis framework. Data were collected through a document review of national policy plans, reports, and evaluations. FINDINGS: A total of 14 papers met the inclusion criteria, showing that climate change adaptation remains a niche in the literature for sub-Saharan Africa. Most included papers were authored by individuals from high-income countries. Health system adaptation measures cover seven domains: health systems strengthening; policy and planning; financing and implementation; information and capacity building; societal resilience; disaster risk prevention, preparedness, response, and recovery; and mitigation. The review found that the dominant role of global agencies in supporting or steering health system adaptation planning contributes to policy mimicry across countries, as confirmed by the case study of the adaptation plan in Benin. Benin's National Adaptation Plan prioritised three climate hazards: heat, drought, and flooding. Although the financial and technical inputs of international agencies effectively support Benin's adaptation planning, these inputs might induce a more narrow focus that does not fully respond to Benin's needs in terms of climate shocks and adaptation priorities. INTERPRETATION: Health systems in sub-Saharan Africa are already adapting to climate change. Future research could focus on how national governments could develop adaptation plans that are responsive to local needs by making the needs analysis and priority-setting processes more inclusive of local stakeholders. FUNDING: The Belgian Directorate-General for Development Cooperation and Humanitarian Aid.

Quantifying Overlapping Forms of Malnutrition Across Latin America: A Systematic Literature Review and Meta-Analysis of Prevalence Estimates.

Estimating the prevalence of double burden of malnutrition (DBM) is challenging in the Latin American and Caribbean (LAC) region where various DBM typologies (e.g., obesity and stunting) are heterogeneous and estimates are scattered across literature This study aimed to assess the prevalence of DBM typologies in the LAC region. We searched PubMed, Embase, Scopus, and Web of Science to identify studies on the prevalence of DBM published between 1 January, 2000, and 23 January, 2023. Outcomes were the prevalence of the identified DBM typologies at the household, individual, or across life course levels. Random-effect meta-analyses of proportions were used to estimate pooled period prevalence for all outcomes. Heterogeneity was explored using meta-regressions. From 754 records identified, 60 (8%) studies were eligible, with a median of 4379 individuals. Studies reported data from 27 LAC countries collected between 1988 and 2017. Most studies used nationally representative surveys (68%) and scored as low risk of bias (70%). We identified 17 DBM typologies for which 360 estimates were analyzed. The prevalence of the identified DBM typologies ranged between 0% and 24%, with the DBM typology of "adult with overweight and child with anemia" having the highest prevalence (24.3%; 95% CI: 18.8%, 30.2%). The most frequently reported DBM typology was "adult with overweight and child with stunting," with a prevalence of 8.5% (95% CI: 7.7, 9.3). All prevalences carried large heterogeneity (I2>90%), modestly explained by subregions and countries. DBM across the life course could not be estimated owing to insufficient estimates. In conclusion, using available data, our study suggests that the burden of DBM in the LAC region ranges between 0% and 24%. In the most frequent DBM typologies, overweight was a common contributor. Substantial progress can be made in curbing the burden of DBM in the LAC region through strategies addressing excess weight within these population groups. This study was registered at PROSPERO as CRD42023406755.

Fasciola spp. in Southeast Asia: A systematic review.

BACKGROUND: Fasciolosis is an emerging public health threat in a number of regions worldwide. To date, we lack an overview of both its occurrence and distribution in Southeast Asia across all actors involved in the life cycle, which impedes the development of disease control measures. Therefore, our objective was to collect recent information on the distribution and the prevalence of Fasciola spp. and the associated risk factors for infection in humans, animals, snails and plant carriers in Southeast Asia. METHODOLOGY: Bibliographic and grey literature databases as well as reference lists of important review articles were searched for relevant records published between January 1st, 2000, and June 30th, 2022. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting systematic reviews. A total of 3,887 records were retrieved, of which 100 were included in the final analysis. PRINCIPAL FINDINGS: The studies focused mainly on one host species (96.0%), with Fasciola spp. infection in animals being the most studied (72.0%), followed by humans (21.0%). Based on the used inclusion and exclusion criteria, reports were retrieved describing the presence of Fasciola spp. infection in seven out of 11 countries in Southeast Asia. Depending on the diagnostic tool applied, the prevalence of Fasciola spp. infection ranged between 0.3% and 66.7% in humans, between 0% and 97.8% in animals, and between 0% and 66.2% in snails. There were no studies reporting the presence of metacercariae on plant carriers. CONCLUSIONS/SIGNIFICANCE: Our study reconfirms that Fasciola spp. infections are widespread and highly prevalent in Southeast Asia, but it remains difficult to accurately assess the true occurrence of Fasciola spp. in absence of well-designed surveys covering all hosts. As next steps we propose to assess the occurrence of the infection across all actors involved in the transmission, to identify associated risk factors and to estimate the burden of the disease to support national and international decision makers.

Profile of Children with Undernutrition Admitted in Two Secondary-Level Hospitals in Maputo City, Mozambique.

Mozambique has one of the highest child undernutrition rates in Sub-Saharan Africa. The aim of this study was to characterize the profile of children from 1 to 14 years old hospitalized for undernutrition and to explore associated risk factors. Clinical, demographic, socioeconomic, and environmental data were collected. Anthropometric measurements and stool samples were collected from a child and their caretaker. The wealth index was determined using Principal Components Analysis. A total of 449 children and their caretakers were enrolled. The children had a median age of 1.0 year [IQR: 1.0-2.0], and 53.9% (242/449) were male. Most were admitted with severe undernutrition (35.7%, 159/449 kwashiorkor and 82.0%, 368/449 with -3SD Z-score indexes). The most common co-morbidities were HIV (30.0%, 120/400), diarrhea (20.0%; 80/400), and anemia (12.5%; 50/400). Among the caretakers, 9.5% (39/409) were underweight, 10.1% (40/397) were overweight, and 14.1% (56/397) were obese. Intestinal parasites were found in 24.8% (90/363) children and in 38.5% (77/200) caretakers. The majority of children (60.7%, 85/140) came from low- to middle-wealth households. Most were severely undernourished, suggesting that they seek medical care too late. The finding of overweight/obese caretakers in combination with undernourished children confirms that Mozambique is facing a double burden of malnutrition.

Treatment and prevention of epilepsy in onchocerciasis-endemic areas is urgently needed.

BACKGROUND: There is increasing epidemiological evidence supporting the association between onchocerciasis and seizures, reinforcing the concept of onchocerciasis-associated epilepsy (OAE). The aim of this paper is to provide an update on the new knowledge about OAE and to propose recommendations to the World Health Organization how to address this public health problem. MAIN TEXT: During the 2nd International Workshop on OAE held on 19-21 September, 2023, in Antwerp, Belgium, participants recognised OAE as a substantial yet neglected public health problem, particularly in areas of sub-Saharan Africa where onchocerciasis remains hyperendemic. Evidence from prospective population-based studies suggest that strengthening onchocerciasis elimination efforts leads to a significant reduction of OAE incidence. There is a need to validate an OAE case definition to estimate the burden of disease and identify onchocerciasis-endemic areas requiring intensification of onchocerciasis elimination programmes and integration of epilepsy care. It is expected that raising awareness about OAE will boost the population uptake of ivermectin. The implementation of a community-based epilepsy treatment programme offering free anti-seizure medications (ASMs) has shown high effectiveness in reducing the frequency of seizures and improving the overall quality of life of people with epilepsy. CONCLUSIONS: To reduce OAE burden, enhanced collaboration between onchocerciasis and mental health programmes at community, national, and international levels is required. Urgent efforts are needed to ensure the uninterrupted provision of free ASMs in onchocerciasis-endemic areas. Furthermore, OAE should be included in the quantification of the onchocerciasis disease burden.

Multiplex PCR for bacterial, viral and protozoal pathogens in persistent diarrhoea or persistent abdominal pain in Côte d'Ivoire, Mali and Nepal.

In contrast to acute diarrhoea, the aetiology of persistent digestive disorders (≥ 14 days) is poorly understood in low-resource settings and conventional diagnostic approaches lack accuracy. In this multi-country study, we compared multiplex real-time PCR for enteric bacterial, parasitic and viral pathogens in stool samples from symptomatic patients and matched asymptomatic controls in Côte d'Ivoire, Mali and Nepal. Among 1826 stool samples, the prevalence of most pathogens was highest in Mali, being up to threefold higher than in Côte d'Ivoire and up to tenfold higher than in Nepal. In all settings, the most prevalent bacteria were EAEC (13.0-39.9%) and Campylobacter spp. (3.9-35.3%). Giardia intestinalis was the predominant intestinal protozoon (2.9-20.5%), and adenovirus 40/41 was the most frequently observed viral pathogen (6.3-25.1%). Significantly different prevalences between symptomatic and asymptomatic individuals were observed for Campylobacter, EIEC and ETEC in the two African sites, and for norovirus in Nepal. Multiple species pathogen infection was common in Côte d'Ivoire and Mali, but rarely found in Nepal. We observed that molecular testing detected multiple enteric pathogens and showed low discriminatory accuracy to distinguish between symptomatic and asymptomatic individuals. Yet, multiplex PCR allowed for direct comparison between different countries and revealed considerable setting-specificity.

Antimalarial artesunate-mefloquine versus praziquantel in African children with schistosomiasis: an open-label, randomized controlled trial.

Schistosomiasis treatment entirely relies on a single drug, praziquantel, prompting research into alternative therapeutics. Here we evaluated the efficacy and safety of the antimalarial combination artesunate-mefloquine for the treatment of schistosomiasis in a proof-of-concept, pragmatic, open-label, randomized controlled trial in primary schools of six villages endemic for schistosomiasis in northern Senegal. Children (6-14 years) were eligible if Schistosoma eggs were detected by microscopy in urine and/or stool. In total, 726 children were randomized 1:1 to praziquantel (standard care: 40 mg kg-1 single dose; n = 364) or to artesunate-mefloquine (antimalarial dosage: artesunate 4 mg kg-1 and mefloquine 8 mg kg-1 daily for three consecutive days; n = 362). Eight children not meeting the inclusion criteria were excluded from efficacy analysis. Median age of the remaining 718 participants was 9 years; 399 (55.6%) were male, and 319 (44.4%) female; 99.3% were infected with Schistosoma haematobium and 15.2% with S. mansoni. Primary outcomes were cure rate, assessed by microscopy, and frequency of drug-related adverse effects of artesunate-mefloquine versus praziquantel at 4 weeks after treatment. Cure rate was 59.6% (208/349) in the artesunate-mefloquine arm versus 62.1% (211/340) in the praziquantel arm. The difference of -2.5% (95% confidence interval (CI) -9.8 to 4.8) met the predefined criteria of noninferiority (margin set at 10%). All drug-related adverse events were mild or moderate, and reported in 28/361 children receiving artesunate-mefloquine (7.8%; 95% CI 5.4 to 11.0) versus 8/363 (2.2%; 95% CI 1.1 to 4.3) receiving praziquantel (P < 0.001). Artesunate-mefloquine at antimalarial dosage was moderately safe and noninferior to standard-care praziquantel for the treatment of schistosomiasis, predominantly due to S. haematobium. Multicentric trials in different populations and epidemiological settings are needed to confirm these findings. ClinicalTrials.gov identifier: NCT03893097 .

Persistent digestive disorders in the tropics: causative infectious pathogens and reference diagnostic tests.

BACKGROUND: Persistent digestive disorders account for considerable disease burden in the tropics. Despite advances in understanding acute gastrointestinal infections, important issues concerning epidemiology, diagnosis, treatment and control of most persistent digestive symptomatologies remain to be elucidated. Helminths and intestinal protozoa are considered to play major roles, but the full extent of the aetiologic spectrum is still unclear. We provide an overview of pathogens causing digestive disorders in the tropics and evaluate available reference tests. METHODS: We searched the literature to identify pathogens that might give rise to persistent diarrhoea, chronic abdominal pain and/or blood in the stool. We reviewed existing laboratory diagnostic methods for each pathogen and stratified them by (i) microscopy; (ii) culture techniques; (iii) immunological tests; and (iv) molecular methods. Pathogen-specific reference tests providing highest diagnostic accuracy are described in greater detail. RESULTS: Over 30 pathogens may cause persistent digestive disorders. Bacteria, viruses and parasites are important aetiologic agents of acute and long-lasting symptomatologies. An integrated approach, consisting of stool culture, microscopy and/or specific immunological techniques for toxin, antigen and antibody detection, is required for accurate diagnosis of bacteria and parasites. Molecular techniques are essential for sensitive diagnosis of many viruses, bacteria and intestinal protozoa, and are increasingly utilised as adjuncts for helminth identification. CONCLUSIONS: Diagnosis of the broad spectrum of intestinal pathogens is often cumbersome. There is a need for rapid diagnostic tests that are simple and affordable for resource-constrained settings, so that the management of patients suffering from persistent digestive disorders can be improved.

Association of both Water, Sanitation and Hygiene (WASH) and Infant and Young Child Feeding (IYCF) practices with childhood malnutrition in Lao PDR: a cross-sectional study of the 2017 Lao Social Indicator Survey II.

OBJECTIVE: We assessed whether Water, Sanitation and Hygiene (WASH) and Infant and Young Child Feeding (IYCF), either alone or combined, were associated with malnutrition among Lao People's Democratic Republic (Lao PDR) children aged 6 to <24 months. DESIGN: This is a secondary analysis of the 2017 Lao Social Indicator Survey II (LSIS II), which used multistage probability proportional to size sampling. Logistic regression analyses were conducted with OR and its corresponding 95% CI. SETTING: The LSIS II was conducted a nationwide household-based survey covering all 18 provinces in Lao PDR. PARTICIPANTS: We had a total of 3375 children (weighted sample 3345) and 357 households with data on drinking water. OUTCOME MEASURES: The outcomes of this study were stunting and wasting. RESULTS: The prevalence of stunting and wasting was 28.9% and 10.1%, respectively. Even though households with access to a basic or improved water source were high (82.5%), over 83% of drinking water was contaminated with Escherichia coli. Access to improved sanitation, basic hygiene and adequate IYCF gave a significant lower risk of becoming stunted. The combined effect of these practices on stunting was (adjusted OR (AOR)=0.54; 95% CI=0.41 to 0.73) greater than each practice alone (improved sanitation: AOR=0.75; 95% CI=0.61 to 0.93; basic hygiene: AOR=0.69; 95% CI=0.57 to 0.83; adequate IYCF: AOR=0.79; 95% CI=0.64 to 0.98). Access to improved sanitation and adequate IYCF was associated with a significant lower risk for being wasted, and again the combined effect of these practices was (AOR=0.64; 95% CI=0.44 to 0.92) greater than each practice alone (improved sanitation: AOR=0.68; 95% CI=0.49 to 0.93 and adequate IYCF: AOR=0.66; 95% CI=0.47 to 0.92). CONCLUSION: Given the strong associations with both stunting and wasting, and the added benefits when combining WASH and IYCF, there is a need of multisectoral interventions to reduce early childhood malnutrition in Lao PDR.