Soil-transmitted Helminth Control Research Articles

SOSIALISASI PENINGKATAN DETEKSI SOIL TRANSMITTED HELMINTH (STH) MELALUI MODIFIKASI PADA LARUTAN ZnS (SULFIDA SENG) DAN NaCl (NATRIUM KLORIDA) 0,9%

Public health is a crucial aspect of disease prevention efforts. One significant health issue in many countries, including Indonesia, is Soil Transmitted Helminth (STH) infection, often caused by poor sanitation and lack of environmental cleanliness awareness. STH, typically caused by Ascaris lumbricoides, Trichuris trichiura, and hookworm, can have severe health impacts, particularly on children. Fecal examination methods, especially flotation techniques using ZnS (zinc sulfide) and 0.9% NaCl (sodium chloride) solutions, are commonly employed for STH detection. However, optimizing flotation methods in the field is essential to enhance STH detection sensitivity. This study focuses on the modification of ZnS and 0.9% NaCl solutions to improve the effectiveness of detecting STH eggs. By disseminating information on these modifications to public health practitioners, this socialization aims to enhance detection and prevention efforts for STH infections. The evaluation results show significant improvements in participants' knowledge, skills, attitudes, understanding, method application, and satisfaction, indicating the effectiveness of this socialization in promoting better STH control and prevention programs.

Efficacy of Single-Dose Albendazole and Albendazole Plus Ivermectin for Soil-Transmitted Helminth Infection in Children in the Peruvian Amazon.

In countries where soil-transmitted helminth (STH) infections are endemic, deworming programs are recommended to reduce morbidity; however, increasing levels of resistance to benzimidazoles are of concern. In an observational study in Peru, we studied the clinical efficacy of 400 mg of albendazole 20 days after treatment among children aged 2-11 years. Of 426 participants who provided samples, 52.3% were infected with a STH, 144 (33.8%) were positive for Ascaris (41.8% light, 50.8% moderate, and 7.4% heavy infections), 147 (34.5%) were positive for Trichuris (75.2% light, 22.5% moderate, and 2.3% heavy infections), and 1.1% were positive for hookworm species (100% light infections). Additional stool samples were examined at 20, 90, and 130 days after the initial treatment. At 20 days post-administration of albendazole, the cure rate (CR) of Ascaris infection was 80.1% (95% CI: 73.5-86.7), and the egg reduction rate (ERR) was 70.8% (95% CI: 57.8-88.7); the CR for Trichuris infection was 27.1% (95% CI: 20.0-34.3), and the ERR was 29.8% (95% CI: -1.40 to 57.5). Among participants with persistent or recurrent infections with Trichuris, the combined therapy of albendazole (400 mg) and ivermectin at 600 µg/dose increased overall CR for Trichuris infection to 75.2% (95% CI: 67.3-83.2%) with an ERR of 84.2% (95% CI: 61.3-93.8%). Albendazole administration alone for the control of STH was associated with high rates of treatment failure, especially for Trichuris. Combined single doses of albendazole and ivermectin was observed to have improved efficacy.

A Comparison of Markov and Mechanistic Models for Soil-Transmitted Helminth Prevalence Projections in the Context of Survey Design.

Globally, there are over 1 billion people infected with soil-transmitted helminths (STHs), mostly living in marginalized settings with inadequate sanitation in sub-Saharan Africa and Southeast Asia. The World Health Organization recommends an integrated approach to STH morbidity control through improved access to sanitation and hygiene education and the delivery of preventive chemotherapy (PC) to school-age children delivered through schools. Progress of STH control programs is currently estimated using a baseline (pre-PC) school-based prevalence survey and then monitored using periodical school-based prevalence surveys, known as Impact Assessment Surveys (IAS). We investigated whether integrating geostatistical methods with a Markov model or a mechanistic transmission model for projecting prevalence forward in time from baseline can improve IAS design strategies. To do this, we applied these 2 methods to prevalence data collected in Kenya, before evaluating and comparing their performance in accurately informing optimal survey design for a range of IAS sampling designs. We found that, although both approaches performed well, the mechanistic method more accurately projected prevalence over time and provided more accurate information for guiding survey design. Both methods performed less well in areas with persistent STH hotspots where prevalence did not decrease despite multiple rounds of PC. Our findings show that these methods can be useful tools for more efficient and accurate targeting of PC. The general framework built in this paper can also be used for projecting prevalence and informing survey design for other neglected tropical diseases.

Diagnosis of soil-transmitted helminth infections with digital mobile microscopy and artificial intelligence in a resource-limited setting.

Infections caused by soil-transmitted helminths (STHs) are the most prevalent neglected tropical diseases and result in a major disease burden in low- and middle-income countries, especially in school-aged children. Improved diagnostic methods, especially for light intensity infections, are needed for efficient, control and elimination of STHs as a public health problem, as well as STH management. Image-based artificial intelligence (AI) has shown promise for STH detection in digitized stool samples. However, the diagnostic accuracy of AI-based analysis of entire microscope slides, so called whole-slide images (WSI), has previously not been evaluated on a sample-level in primary healthcare settings in STH endemic countries. Stool samples (n = 1,335) were collected during 2020 from children attending primary schools in Kwale County, Kenya, prepared according to the Kato-Katz method at a local primary healthcare laboratory and digitized with a portable whole-slide microscopy scanner and uploaded via mobile networks to a cloud environment. The digital samples of adequate quality (n = 1,180) were split into a training (n = 388) and test set (n = 792) and a deep-learning system (DLS) developed for detection of STHs. The DLS findings were compared with expert manual microscopy and additional visual assessment of the digital samples in slides with discordant results between the methods. Manual microscopy detected 15 (1.9%) Ascaris lumbricoides, 172 (21.7%) Tricuris trichiura and 140 (17.7%) hookworm (Ancylostoma duodenale or Necator americanus) infections in the test set. Importantly, more than 90% of all STH positive cases represented light intensity infections. With manual microscopy as the reference standard, the sensitivity of the DLS as the index test for detection of A. lumbricoides, T. trichiura and hookworm was 80%, 92% and 76%, respectively. The corresponding specificity was 98%, 90% and 95%. Notably, in 79 samples (10%) classified as negative by manual microscopy for a specific species, STH eggs were detected by the DLS and confirmed correct by visual inspection of the digital samples. Analysis of digitally scanned stool samples with the DLS provided high diagnostic accuracy for detection of STHs. Importantly, a substantial number of light intensity infections were missed by manual microscopy but detected by the DLS. Thus, analysis of WSIs with image-based AI may provide a future tool for improved detection of STHs in a primary healthcare setting, which in turn could facilitate monitoring and evaluation of control programs.

Serological diagnosis of soil-transmitted helminth (Ascaris, Trichuris and hookworm) infections: A scoping review.

The World Health Organization emphasizes the importance of integrated monitoring and evaluation in neglected tropical disease (NTD) control programs. Serological assays offer a potential solution for integrated diagnosis of NTDs, particularly for those requiring mass drug administration (MDA) as primary control and elimination strategy. This scoping review aims (i) to provide an overview of assays using serum or plasma to detect infections with soil-transmitted helminths (STHs) in both humans and animals, (ii) to examine the methodologies used in this research field and (iii) to discuss advancements in serological diagnosis of STHs to guide prevention and control programs in veterinary and human medicine. We conducted a systematic search in the Ovid MEDLINE, Embase and Cochrane Library databases, supplemented by a Google search using predefined keywords to identify commercially available serological assays. Additionally, we performed a patent search through Espacenet. We identified 85 relevant literature records spanning over 50 years, with a notable increased interest in serological assay development in recent years. Most of the research efforts concentrated on diagnosing Ascaris infections in both humans and pigs, primarily using ELISA and western blot technologies. Almost all records targeted antibodies as analytes, employing proteins and peptides as analyte detection agents. Approximately 60% of sample sets described pertained to human samples. No commercially available tests for Trichuris or hookworms were identified, while for Ascaris, there are at least seven different ELISAs on the market. While a substantial number of assays are employed in epidemiological research, the current state of serological diagnosis for guiding STH prevention and control programs is limited. Only two assays designed for pigs are used to inform efficient deworming practices in pig populations. Regarding human diagnosis, none of the existing assays has undergone extensive large-scale validation or integration into routine diagnostics for MDA programs.

Exploring factors associated with Trichuris trichiura infection in school children in a high-transmission setting in Kenya

ObjectivesKenya has implemented a national school-based deworming program, which has led to substantial decline in the prevalence of soil-transmitted helminths (STHs), although some pockets of infections remain. To effectively design an STH control program that leads to significant reductions of Trichuris trichiura, there is a need to understand the drivers of persistent infection despite ongoing treatment programs. MethodsThis study was conducted between July and September 2019 at the south coast of Kenya, using a two-stage sampling design. First, a school-based cross-sectional survey was conducted in 2265 randomly selected school children from selected schools in areas known to be endemic for T. trichiura. After this, we conducted a nested case-control study wherein all children positive for T. trichiura (142) were matched to 148 negative controls based on age and village. A household survey was then conducted with all household members of cases and controls. In addition, a subsample of 116 children found to be infected with T. trichiura were followed up to assess the efficacy of albendazole at day 21 post-treatment. The predictors of presence of T. trichiura were investigated through multilevel logistic regression, considering clustering of infection. ResultsOverall, 34.4% of the children were infected with at least one STH species; T. trichiura was the most common (28.3%), 89.1% of those with T. trichiura had light-intensity infections. The prevalence of T. trichiura was significantly higher in male children and was positively associated with younger age and number of people infected with T. trichiura in a household. The parasitological cure rate and egg reduction rate of T. trichiura were 35% and 51%, respectively. Other STHs identified were hookworm (9.6%) and Ascaris lumbricoides (5.7%). ConclusionsT. trichiura remains a significant public health challenge in the study area with albendazole treatment efficacy against the parasite, remaining lower than the World Health Organization–recommended thresholds. Because of the observed focal transmission of T. trichiura in the current area, control efforts tailored to local conditions and targeting lower implementation units should be used to achieve optimal results on transmission.

A One Health approach toward the control and elimination of soil-transmitted helminthic infections in endemic areas

Soil-transmitted helminths (STHs) pose significant health challenges, particularly in developing countries. Over 2 billion people are estimated to have been infected with at least one STH species. These parasites rely on the soil for part of their life cycle and are transmitted to humans through ova ingestion or skin penetration. Key risk factors include poor water, sanitation, hygiene practices, limited healthcare access, and poverty. Globally, STHs are primarily controlled through chemo-preventive deworming of high-risk groups in moderate (where prevalence of STHs is between 20 % and 50 %) to highly endemic areas (prevalence >50 %). Despite the use of deworming to control the STHs in endemic areas, infections still occur. The aim of this article is to explore the potential for enhancing STH control and elimination as Neglected Tropical Diseases (NTDs) in endemic areas through an integrated approach—the One Health approach. The current control program has a single strategy of chemoprophylaxis; in the integrated approach to control of STHs, the parasite control strategies besides being based on the epidemiology of the parasite (endemicity), also include strategies based on the biology (transmission cycle) of the parasites and human behavior patterns in endemic areas. Through the involvement of local communities, healthcare authorities, and stakeholders, participatory approaches foster collaborative efforts to devise and implement control measures. By integrating this integrated approach into existing healthcare and educational initiatives, more effective results can be achieved. The promotion of health education, clean water access, improved sanitation, and hygiene awareness can further enhance control strategies and reduce STH prevalence sustainably. Here, we highlight the benefits of adopting an integrated (One Health) approach to tackle STHs in endemic areas. Through community empowerment and multi-sectorial collaboration, we can strengthen our collective efforts to combat STHs and alleviate the burden of these NTDs.

Predicting the risk and speed of drug resistance emerging in soil-transmitted helminths during preventive chemotherapy

Control of soil-transmitted helminths relies heavily on regular large-scale deworming of high-risk groups (e.g., children) with benzimidazole derivatives. Although drug resistance has not yet been documented in human soil-transmitted helminths, regular deworming of cattle and sheep has led to widespread benzimidazole resistance in veterinary helminths. Here we predict the population dynamics of human soil-transmitted helminth infections and drug resistance during 20 years of regular preventive chemotherapy, using an individual-based model. With the current preventive chemotherapy strategy of mainly targeting children in schools, drug resistance may evolve in soil-transmitted helminths within a decade. More intense preventive chemotherapy strategies increase the prospects of soil-transmitted helminths elimination, but also increase the speed at which drug efficacy declines, especially when implementing community-based preventive chemotherapy (population-wide deworming). If during the last decade, preventive chemotherapy against soil-transmitted helminths has led to resistance, we may not have detected it as drug efficacy has not been structurally monitored, or incorrectly so. These findings highlight the need to develop and implement strategies to monitor and mitigate the evolution of benzimidazole resistance.

Prevalence of Soil-Transmitted Helminth Infections in Malaysia: A Systematic Review and Meta-Analysis

BACKGROUND: Prevention and control of soil-transmitted helminth (STH) infections in Malaysia remain a challenge, especially among aborigine and rural population. Despite several community-based reports, there are lacking national data on the overall prevalence for STH infection. AIM: The study aimed to determine the prevalence, endemic species, and distribution and risk zones (RZs) for STH infections in Malaysia through a systematic review and meta-analysis of the data published between 1999 and 2019. METHODS: This study employed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The databases used in this review include SCOPUS, WEB OF SCIENCE, OVID MEDLINE, and PUBMED. The random-effects model determined the pooled prevalence estimate (PPE) while Cochran’s Q-test evaluated the heterogeneity. RESULTS: A total of 13240 samples were examined during the period under review with 6235 were infected with one or more species of STHs. The overall PPE for STH infections was 51% (95% Confidence interval [CI]: 34, 67). PPEs for sub-groups ranged between 13% (95% CI: 5, 22) and 69% (95% CI: 50, 87). Highest PPEs for STH infections were observed among aborigine children (69% 95% CI: 50, 87). Trichuris trichiura was the most prevalent species (46%, 95% CI: 27, 65). Over 46% (17/37) of the studies, especially among aborigine community and their area showed high-HRZ for STH infections. CONCLUSION: STH infections involving T. trichiura, Ascaris lumbricoides, hookworms and Strongyloides stercoralis are highly prevalent among aborigine community. Primary and secondary prevention such as the use of anthelmintic, health education, and adequate sanitation was essential in the control of these infections in Malaysia to improve individual and community health.

Identifying opportunities to optimize mass drug administration for soil-transmitted helminths: A visualization and descriptive analysis using process mapping.

The control of soil-transmitted helminths (STH) is achieved through mass drug administration (MDA) with deworming medications targeting children and other high-risk groups. Recent evidence suggests that it may be possible to interrupt STH transmission by deworming individuals of all ages via community-wide MDA (cMDA). However, a change in delivery platforms will require altering implementation processes. We used process mapping, an operational research methodology, to describe the activities required for effective implementation of school-based and cMDA in 18 heterogenous areas and over three years in Benin, India, and Malawi. Planned activities were identified during workshops prior to initiation of a large cMDA trial (the DeWorm3 trial). The process maps were updated annually post-implementation, including adding or removing activities (e.g., adaptations) and determining whether activities occurred according to plan. Descriptive analyses were performed to quantify differences and similarities at baseline and over three implementation years. Comparative analyses were also conducted between study sites and areas implementing school-based vs. cMDA. Digitized process maps were developed to provide a visualization of MDA processes and inspected to identify implementation bottlenecks and inefficient activity flows. Across three years and all clusters, implementation of cMDA required an average of 13 additional distinct activities and was adapted more often (5.2 adaptations per year) than school-based MDA. An average of 41% of activities across both MDA platforms did not occur according to planned timelines; however, deviations were often purposeful to improve implementation efficiency or effectiveness. Visualized process maps demonstrated that receipt of drugs at the local level may be an implementation bottleneck. Many activities rely on the effective setting of MDA dates and estimating quantity of drugs, suggesting that the timing of these activities is important to meet planned programmatic outcomes. Implementation processes were heterogenous across settings, suggesting that MDA is highly context and resource dependent and that there are many viable ways to implement MDA. Process mapping could be deployed to support a transition from a school-based control program to community-wide STH transmission interruption program and potentially to enable integration with other community-based campaigns. NCT03014167.

Mass drug administration campaigns: comparing two approaches for schistosomiasis and soil-transmitted helminths prevention and control in selected Southern Malawi districts

BackgroundMass drug administration is one of the key interventions recommended by WHO to control certain NTDs. With most support from donors, health workers distribute antihelminthic drugs annually in Malawi. Mean community coverage of MDA from 2018 to 2020 was high at 87% for praziquantel and 82% for albendazole. However, once donor support diminishes sustaining these levels will be challenging. This study intended to compare the use of the community-directed intervention approach with the standard practice of using health workers in delivery of MDA campaigns.MethodsThis was a controlled implementation study carried out in three districts, where four health centres and 16 villages in each district were selected and randomly assigned to intervention and control arms which implemented MDA campaigns using the CDI approach and the standard practice, respectively. Cross-sectional and mixed methods approach to data collection was used focusing on quantitative data for coverage and knowledge levels and qualitative data to assess perceptions of health providers and beneficiaries at baseline and follow-up assessments. Quantitative and qualitative data were analyzed using IBM SPSS software version 26 and NVivo 12 for Windows, respectively.ResultsAt follow-up, knowledge levels increased, majority of the respondents were more knowledgeable about what schistosomiasis was (41%-44%), its causes (41%-44%) and what STH were (48%-64%), while knowledge on intermediate host for schistosomiasis (19%-22%), its types (9%-13%) and what causes STH (15%-16%) were less known both in intervention and control arm communities. High coverage rates for praziquantel were registered in intervention (83%-89%) and control (86%-89%) communities, intervention (59%-79) and control (53%-86%) schools. Costs for implementation of the study indicated that the intervention arm used more resources than the control arm. Health workers and community members perceived the use of the CDI approach as a good initiative and more favorable over the standard practice.ConclusionsThe use of the CDI in delivery of MDA campaigns against schistosomiasis and STH appears feasible, retains high coverages and is acceptable in intervention communities. Despite the initial high costs incurred, embedding into community delivery platforms could be considered as a possible way forward addressing the sustainability concern when current donor support wanes.Trial registrationPan-African Clinical Trials Registry PACTR202102477794401, date: 25/02/2021.

Patterns of individual compliance with anthelmintic treatment for soil-transmitted helminth infections in southern Ethiopia over six rounds of community-wide mass drug administration.

The mainstay of soil-transmitted helminth (STH) control is repeated mass drug administration (MDA) of anthelmintics to endemic populations. Individual longitudinal compliance treatment patterns are important for identifying pockets of infected individuals who remain untreated and serve as infection reservoirs. The Geshiyaro Project censused the study population in Wolaita, Ethiopia at baseline in 2018. Individual longitudinal compliance was recorded for six rounds of community-wide MDA (cMDA). The probability distribution of treatment frequency was analysed by age and gender stratifications. Probabilities of transmission interruption for different compliance patterns were calculated using an individual-based stochastic model of Ascaris lumbricoides transmission. The never-treated (0.42%) population was smaller than expected from a random positive binomial distribution. The observed compliance frequency was well described by the beta-binomial distribution. Preschool-age children (odds ratio [OR] 10.1 [95% confidence interval {CI} 6.63 to 15.4]) had the highest never-treated proportion of the age groups. Conversely, school-age children (SAC) and adults (OR 1.03 [95% CI 0.98 to 1.09]) had the highest always-treated proportion of the age groups. The study reports the largest dataset of individual longitudinal compliance to cMDA for STH control. Clear pattens are shown in the age-dependent distribution of individual compliance behaviour. The impact of compliance on the probability of elimination is significant, highlighting the importance of recording the full frequency distribution, not just the never-treated proportion.

Effectiveness of one and two doses of ivermectin mass drug administration in reducing the prevalence and intensity of soil-transmitted helminth (STH) infections in Western Province, Solomon Islands: a cluster-randomised, before-after analysis

Ivermectin mass drug administration (MDA) is effective for controlling onchocerciasis and scabies, with evidence supporting its role in some species of soil-transmitted helminth (STH) infections. In the context of RISE, a cluster-randomised trial for scabies, this study evaluated the effectiveness of ivermectin MDA in reducing STH burden in the Western Province of Solomon Islands. Twenty villages were randomised 1:1 to receive ivermectin MDA as one dose (IVM-1) or two doses (IVM-2) for scabies. The effectiveness of one and two doses in reducing STH prevalence and intensity was evaluated before (May 2019) and 21 months after (February 2021) MDA in May 2019. All residents aged 12 months or older in the study villages were eligible to participate and provide stool specimens. Species-specific STH infection and intensity were assessed using quantitative PCR. We compared prevalence and intensity of infection between baseline and 21 months in each intervention arm individually using cluster-level analysis (adjusted for clustering) and individual-level analysis (adjusted for sex, age, and clustering). The primary outcomes were the prevalence risk difference (RD) from the cluster-level analysis, and the change in adjusted odds of infection from the individual-level analysis. Secondary outcomes included change in incident rates of mean eggs per gram (epg) of stool from baseline to 21 months, relative risk difference in prevalence and relative change in odds of infection between arms at 21 months. Sex data (male/female) were self-reported. Overall, STH infection was assessed in 830 participants from 18 villages at baseline and 1172 from 20 villages at follow-up. Females represented 58% (n=478) of the sample at baseline and 59% (n=690) at follow-up. We observed a reduction in Strongyloides spp. prevalence following two doses of ivermectin MDA in the cluster-level analysis from 7.0% (32/458 participants) to 1.2% (8/674 participants), corresponding to a RD of-0.07 (95% CI-0.14 to-0.01, p=0.036), and in the individual-level analysis (OR 0.11, 95% CI 0.04-0.33, p<0.001). T.trichiura prevalence decreased following one dose from 19.4% (74/372 participants) to 11.7% (56/505 participants) (OR 0.44, 95% CI 0.26-0.73, p=0.0040), while egg count reduced in both arms (IVM-1: IRR 0.28, 95% CI 0.11-0.70, p=0.0070; IVM-2: IRR 0.18, 95% CI 0.08-0.40, p<0.001), in the individual-level analysis. We did not detect a significant difference in effect measures between the one- and two-dose arms for any species after 21 months. Our study highlights the long-term benefits of ivermectin MDA in reducing the burden of Strongyloides spp. and T.trichiura. STH control programs should leverage the geographical overlap of NTDs, existing drug distribution channels, and broad-spectrum agents. The National Health and Medical Research Council of Australia.

Cost and cost-effectiveness analysis of mass drug administration compared to school-based targeted preventive chemotherapy for hookworm control in Dak Lak province, Vietnam

School-based targeted preventive chemotherapy (PC), the main strategy for soil-transmitted helminths (STH) control, excludes other at-risk populations including adults and preschool children. Mass drug administration (MDA), covering all age groups, would bring additional health benefits but also requires greater investment. This cost survey and cost-effectiveness analysis compared MDA with school-based targeted PC for STH control in Dak Lak, Vietnam, where STH are endemic. A cost survey was conducted in 2020 to estimate the total and per person economic and financial cost of each strategy. Monte Carlo simulation accounted for uncertainty in cost estimates. The primary effectiveness measure was hookworm-related disability-adjusted life years (DALYs) averted, and secondary measures were hookworm infection-years averted and moderate-to-heavy intensity hookworm infection-years averted. A Markov model was used to determine the incremental cost-effectiveness ratio (ICER) of MDA compared to school-based targeted PC using a government payer perspective and a ten-year time horizon. One-way and probabilistic sensitivity analyses (PSA) were performed. Costs are reported in 2020 USD ($). The economic cost per person was $0.27 for MDA and $0.43 for school-based targeted PC. MDA in Dak Lak will cost $472,000 per year, while school-based targeted PC will cost $117,000. Over 10 years, MDA is estimated to avert an additional 121,465 DALYs; 4,019,262 hookworm infection-years, and 765,844 moderate-to-heavy intensity hookworm infection-years compared to school-based targeted PC. The ICER was $28.55 per DALY averted; $0.87 per hookworm infection-years averted, and $4.54 per moderate-to-heavy intensity hookworm infection-years averted. MDA was cost-effective in all PSA iterations. In areas where hookworm predominates and adults suffer a significant burden of infection, MDA is cost effective compared to school based targeted PC and is the best strategy to achieve global targets. The project was funded by the National Health and Medical Research Council (NHMRC) of Australia (Project Grant APP1139561) and JPCDT was supported by a UNSW Scientia PhD Scholarship.

Community-wide versus school-based targeted deworming for soil-transmitted helminth control in school-aged children in Vietnam: the CoDe-STH cluster-randomised controlled trial

Soil-transmitted helminth (STH) infection control programs typically consist of school-based preventive chemotherapy (PC) targeted to school-aged children. STH reservoirs in untreated community members contribute to ongoing transmission in children. The CoDe-STH (Community Deworming against STH) trial, conducted in Dak Lak province, Vietnam, between October 2019 and November 2020, aimed to determine whether community-wide mass drug administration (MDA) is more effective than school-based targeted PC in reducing STH prevalence and intensity in children. In this two-arm cluster randomised controlled trial, 64 primary schools were randomly assigned 1:1 to receive either school-based targeted PC ("school arm") or community-wide MDA ("community arm"). A single dose of albendazole 400mg was used for deworming. The primary outcome was hookworm prevalence in schoolchildren, measured using quantitative real-time PCR. We also measured infection intensity for Necator americanus only, using qPCR cycle threshold (Ct) values converted into eggs per gram of faeces (EPG). Analysis was by intention to treat. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12619000309189). The analysis included 4955 children in the school arm and 5093 children in the community arm. N.americanus was the dominant STH species. The relative reduction in hookworm prevalence was not significantly different between the school arm (30.1%, 95% confidence interval [CI] 20.5-36.9) and the community arm (34.6%, 95% CI 19.9-49.4). Due to lower baseline prevalence than expected, the study was underpowered to detect a difference in prevalence reduction between the study arms. The community arm showed significantly greater relative reduction in N.americanus infection intensity (56.0%, 95% CI 39.9-72.1) compared to the school arm (3.4%, 95% CI-24.7 to 31.4). The community arm also showed greater relative reduction in prevalence of moderate-to-heavy intensity (≥2000 EPG) N.americanus infections (81.1%; 95% CI 69.7-92.6) compared to the school arm (39.0%, 95% CI 13.7-64.2). Although no impact was seen on overall prevalence, community-wide MDA was more effective in lowering N.americanus infection intensity in schoolchildren compared to school-based targeted PC, measured 12 months after one round of albendazole deworming with high coverage. National Health and Medical Research Council, Australia (APP1139561).

Perceptions Associated with Noncompliance to Community-Wide Mass Drug Administration for Soil-Transmitted Helminths.

Mass drug administration (MDA) is a key strategy for the control of soil-transmitted helminths (STHs). Within MDA programs, poor and non-random compliance threaten successful control of STHs. A case-control study was conducted comparing perceptions among non-compliant participants with compliant participants during a community-wide MDA (cMDA) with albendazole in southern India. Common reasons cited for non-compliance were that the individual was not infected with STH (97.4%), the perception that he/she was healthy (91%), fear of side-effects (12.8%), and dislike of consuming tablets (10.3%). Noncompliance was associated with poor awareness of intestinal worms (odds ratio [OR]: 9.63, 95% CI: 2.11-43.84), the perception that cMDA was only required for those with worms (OR: 2.14, 95% CI: 1.06-4.36), and the perception that the drug is not safe during pregnancy (OR: 2.19, 95% CI: 1.18-4.07) or when on concomitant medications (OR: 3.14, 95% CI: 1.38-7.15). Understanding of perceptions driving noncompliance can provide valuable insights to optimize participation during MDA for STHs.

Knowledge, attitudes, practices and acceptability of a school preventive chemotherapy programme for schistosomiasis and soil-transmitted helminths control in Angola.

Schistosomiasis and soil-transmitted helminth (STH) control programs require target population engagement, assessed through knowledge, attitudes and practices (KAP) surveys. We report the results of a KAP survey of Angolan schoolchildren supported by a school preventive chemotherapy (PC) programme, without or with a school water, sanitation and hygiene (WASH) programme (PC+/WASH- and PC+/WASH+, respectively); and schoolchildren without a school PC or WASH program (PC-/WASH-). Schoolchildren from PC+/WASH- (N = 218), PC+/WASH+ (N = 250) and PC-/WASH- (N = 254) schools were interviewed. Descriptive statistics were used to report demographics and survey responses. Chi-square or Fisher's exact test was used to compare PC+/WASH- schoolchildren with (i) PC+/WASH+ and (ii) PC-/WASH- schoolchildren. A lower proportion of PC+/WASH- schoolchildren used latrines and a higher proportion practised open defecation at school compared with PC+/WASH+ schoolchildren. A lower proportion of PC+/WASH- schoolchildren always washed their hands after toileting and before meals at school compared with PC+/WASH+ schoolchildren. However, the PC+/WASH- schoolchildren reported better toileting and handwashing practices at school compared to PC-/WASH- schoolchildren. Over 90% of PC+ schoolchildren agreed with schistosomiasis and STH control and accepted schoolteacher PC delivery. Expanding the integration of both school PC and WASH programs will improve health behaviours relevant to reduce the risk of schistosomiasis and STHs in schoolchildren. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.

Evaluation of Kato-Katz and multiplex quantitative polymerase chain reaction performance for clinical helminth infections in Thailand using a latent class analysis.

Using an appropriate diagnostic tool is essential to soil-transmitted helminth control and elimination efforts. Kato-Katz (KK) is the most commonly used diagnostic, but recently other tools, such as real-time quantitative polymerase chain reaction (multiplex qPCR), are starting to be employed more. Here, we evaluated the performance of these two diagnostic tools for five helminth species in Thailand. In the absence of a gold standard, diagnostic performance can be evaluated using latent class analysis. Our results suggest that in moderate to high prevalence settings above 2% multiplex qPCR could be more sensitive than KK, this was particularly apparent for Opisthorchis viverrini in the northeastern provinces. However, for low prevalence, both diagnostics suffered from low sensitivity. Specificity of both diagnostics was estimated to be high (above 70%) across all settings. For some specific helminth infection such as O. viverrini, multiplex qPCR is still a preferable choice of diagnostic test. KK performed equally well in detecting Ascaris lumbricoides and Taenia solium when the prevalence is moderate to high (above 2%). Neither test performed well when the prevalence of infection is low (below 2%), and certainly in the case for hookworm and Trichuris trichiura. Combination of two or more diagnostic tests can improve the performance although the cost would be high. Development of new methods for helminth surveillance at the pre-elimination phase is therefore very important. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.

A general framework to support cost-efficient survey design choices for the control of soil-transmitted helminths when deploying Kato-Katz thick smear.

To monitor and evaluate soil-transmitted helminth (STH) control programs, the World Health Organization (WHO) recommends screening stools from 250 children, deploying Kato-Katz thick smear (KK). However, it remains unclear whether these recommendations are sufficient to make adequate decisions about stopping preventive chemotherapy (PC) (prevalence of infection <2%) or declaring elimination of STHs as a public health problem (prevalence of moderate-to-heavy intensity (MHI) infections <2%). We developed a simulation framework to determine the effectiveness and cost of survey designs for decision-making in STH control programs, capturing the operational resources to perform surveys, the variation in egg counts across STH species, across schools, between and within individuals, and between repeated smears. Using this framework and a lot quality assurance sampling approach, we determined the most cost-efficient survey designs (number of schools, subjects, stool samples per subject, and smears per stool sample) for decision-making. For all species, employing duplicate KK (sampling 4 to 6 schools and 64 to 70 subjects per school) was the most cost-efficient survey design to assess whether prevalence of any infection intensity was above or under 2%. For prevalence of MHI infections, single KK was the most cost-efficient (sampling 11 to 25 schools and 52 to 84 children per school). KK is valuable for monitoring and evaluation of STH control programs, though we recommend deploying a duplicate KK on a single stool sample to stop PC, and a single KK to declare the elimination of STHs as a public health problem.

A general framework to support cost-efficient fecal egg count methods and study design choices for large-scale STH deworming programs-monitoring of therapeutic drug efficacy as a case study.

Soil-transmitted helminth (STH) control programs currently lack evidence-based recommendations for cost-efficient survey designs for monitoring and evaluation. Here, we present a framework to provide evidence-based recommendations, using a case study of therapeutic drug efficacy monitoring based on the examination of helminth eggs in stool. We performed an in-depth analysis of the operational costs to process one stool sample for three diagnostic methods (Kato-Katz, Mini-FLOTAC and FECPAKG2). Next, we performed simulations to determine the probability of detecting a truly reduced therapeutic efficacy for different scenarios of STH species (Ascaris lumbricoides, Trichuris trichiura and hookworms), pre-treatment infection levels, survey design (screen and select (SS); screen, select and retest (SSR) and no selection (NS)) and number of subjects enrolled (100-5,000). Finally, we integrated the outcome of the cost assessment into the simulation study to estimate the total survey costs and determined the most cost-efficient survey design. Kato-Katz allowed for both the highest sample throughput and the lowest cost per test, while FECPAKG2 required both the most laboratory time and was the most expensive. Counting of eggs accounted for 23% (FECPAKG2) or ≥80% (Kato-Katz and Mini-FLOTAC) of the total time-to-result. NS survey designs in combination with Kato-Katz were the most cost-efficient to assess therapeutic drug efficacy in all scenarios of STH species and endemicity. We confirm that Kato-Katz is the fecal egg counting method of choice for monitoring therapeutic drug efficacy, but that the survey design currently recommended by WHO (SS) should be updated. Our generic framework, which captures laboratory time and material costs, can be used to further support cost-efficient choices for other important surveys informing STH control programs. In addition, it can be used to explore the value of alternative diagnostic techniques, like automated egg counting, which may further reduce operational costs. ClinicalTrials.gov NCT03465488.