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Mozambique is making progress towards elimination of trachoma as a public health problem, but in some districts trachomatous inflammation-follicular (TF) prevalence remains above the 5% elimination threshold despite years of various interventions, including antibiotic mass drug administration. To characterize transmission in four districts, we incorporated testing of ocular infection and serology into routine trachoma impact surveys (TIS) in August 2022. We examined residents aged ≥ 1 year for trachoma and collected information on household water, sanitation, and hygiene. Among children aged 1-9 years, we tested conjunctival swabs for Chlamydia trachomatis nucleic acid and dried blood spots for C. trachomatis antibodies. We modeled age-dependent seroprevalence to estimate seroconversion rate (SCR). We examined 4841 children aged 1-9 years. TF prevalence ranged between 1.1 and 6.0% with three districts below the 5% threshold. PCR-confirmed infection prevalence ranged between 1.1 and 4.8%, and Pgp3 seroprevalence ranged between 8.8 and 24.3%. Pgp3 SCR was 1.9 per 100 children per year in the district with the lowest TF prevalence. Two other districts with TF < 5% had SCR of 5.0 and 4.7. The district with TF ≥ 5% had a SCR of 6.0. This enhanced TIS furthered understanding of transmission in these districts and provides information on additional indicators for monitoring trachoma programs., (© 2024. The Author(s).)

Background: Soil-transmitted helminths (STH) affect approximately 1.5 billion people globally. The current STH control strategy is annual or twice-annual preventive chemotherapy, typically school-based deworming targeting children and women of reproductive age. Mathematical modeling suggests that it may be possible to interrupt STH transmission through high-coverage community-wide mass drug administration (cMDA). DeWorm3 is a cluster randomized trial testing cMDA for prevalence reduction and transmission interruption. The purpose of this study is to describe coverage of cMDA in study clusters over time and correlates of coverage at individual and cluster levels., Methods: From 2018-2020, DeWorm3 delivered six rounds of cMDA with 400 mg albendazole at sites in Benin, India, and Malawi. We report coverage, treatment uptake, and directly observed therapy across all rounds. Factors associated with coverage at the cluster level were identified using binomial generalized estimating equations, while factors associated with non-treatment at the individual level were identified using binomial mixed-effects models., Results: Coverage was high across all clusters and rounds, exceeding the WHO target of 75% in all sites and across all rounds (78% to 95%); cluster-level coverage tended to increase over time. Younger, unmarried, and migratory adults were more likely to be untreated at all sites; adult males were more likely to be untreated in Benin and Malawi. Among children, girls were more likely to be untreated, as were non-school-attending and migratory children. Higher adult education was associated with greater odds of non-treatment among adults, but lower odds among children in the household. Belonging to a less wealthy or minority language-speaking household was associated with non-treatment among both adults and children., Conclusions: It is possible to deliver community-wide MDA with high coverage. Unique individual and community-level factors influence treatment across settings, and these may be addressed through targeted programming., Trial Registration: Field Studies on the Feasibility of Interrupting the Transmission of Soil-transmitted Helminths (STH), NCT03014167., (© 2024. The Author(s).)

Despite the large number of children in India, there is little information on the impact of children's disability on school enrolment, and how this differs by population. We estimated the prevalence of childhood disability in two sites in Tamil Nadu, southern India, and the effect of functional difficulty on school enrolment. We used a parent-reported survey containing the UNICEF-Washington Group questions to identify children aged 5 to 17 years with functional difficulty during a census conducted for an ongoing trial. We estimated pooled- and gender-specific prevalence of functional difficulty among 29,044 children. We fitted regression models to identify subgroups with higher rates of functional difficulty and the effect of functional difficulty on reported school enrolment. We estimated the modification of the effect of functional difficulty by age, gender, socioeconomic status, household education, and sub-site, on additive and multiplicative scales. We found of 29,044 children, 299 (1.0%) had any functional difficulty, equal among boys and girls. Being understood (0.5%) and walking (0.4%) were the most common difficulties. Functional difficulty was strongly associated with non-enrolment in school (Prevalence ratio [PR] 4.59, 95% CI: 3.87, 5.43) after adjusting for age, gender, and site. We show scale-dependent differences between age and socioeconomic groups in the effect of functional difficulty on enrolment. This study shows that at least one in a hundred children in this region have severe functional difficulties and nearly half of these children are not enrolled in school, highlighting the need for further efforts and evidence-based interventions to increase school enrolment among these groups., (© 2024. The Author(s).)

Background: One-fifth of the global population is infected with soil-transmitted helminths (STH). Mass drug administration (MDA) with deworming medication is widely implemented to control morbidity associated with STH infections. However, surveillance of human infection prevalence by collecting individual stool samples is time-consuming, costly, often stigmatized, and logistically challenging. Current methods of STH detection are poorly sensitive, particularly in low-intensity and low-prevalence populations., Methodology/principal Findings: We aimed to develop a sensitive and specific molecular method for detecting STH DNA in large volumes of soil (20 g) by conducting laboratory and proof of concept studies across field sites in Kenya, Benin, and India. We collected human stool (n = 669) and soil (n = 478) from 322 households across the three study sites. We developed protocols for DNA extraction from 20 g of soil and qPCR to detect Ascaris lumbricoides, Trichuris trichiura, Necator americanus, and Ancylostoma duodenale. Agreement between detection of STH via qPCR, digital droplet PCR (ddPCR), and microscopy-based methods was assessed using the Cohen's Kappa statistic. Finally, we estimated associations between soil characteristics and detection of STH in soil by qPCR, as well as between STH detected in soil and STH detected in stool from matched households, adjusting for soil characteristics. The overall prevalence of STH in soil by qPCR was 31% for A. lumbricoides, 3% for T. trichiura, and 13% for any hookworm species. ddPCR and qPCR performed similarly. However, there was poor agreement between STH detected in soil by qPCR versus light microscopy. Microscopy underestimated the prevalence of A. lumbricoides and N. americanus and overestimated T. trichiura. Detection of an STH species in household soil was strongly associated with increased odds of a household member being infected with that same species., Conclusions/significance: Soil surveillance for STH has several benefits over stool-based surveillance, including lower cost and higher success rates for sample collection. Considering that delivery of MDA occurs at the community level, environmental surveillance using molecular methods could be a cost-effective alternate strategy for monitoring STH in these populations., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Manuel et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Between 2000 and 2017/2018, Morocco reduced its maternal mortality ratio by 68% and its neonatal mortality rate by 52%-a higher improvement than other North African countries. We conducted the Exemplars in Maternal and Neonatal Health study to systematically and comprehensively research factors associated with this rapid reduction in mortality over the past two decades., Methods: The study was conducted from September 2020 to December 2021 using mixed methods, including: literature, database and document reviews, quantitative analyses of national data sets and qualitative key-informant interviews at national and district levels. Analyses were based on a conceptual framework of drivers of health and survival of mothers and neonates., Results: A favourable political and economic environment, and a high political commitment encouraged prioritisation of maternal and neonatal health (MNH) by aligning evidence-based policy and technical approaches. Five main factors accounted for Morocco's success: (1) continuous increases in antenatal care and institutional delivery and reductions socioeconomically-based inequalities in MNH service usage; (2) health-system strengthening by expanding the network of health facilities, with increased uptake of facility birthing, scale-up of the production of midwives, reductions in financial barriers and, later in the process, attention to improving the quality of care; (3) improved underlying health status of women and changes in reproductive patterns; (4) a supportive policy and infrastructure environment; and 5) increased education and autonomy of women., Conclusion: Our study provides evidence that supportive changes in Morocco's policy environment for maternal health, backed by greater political will and increased resources, significantly contributed to the dramatic progress in reducing maternal and neonatal mortality. While these efforts were successful in improving MNH in Morocco, several implementation challenges still require special attention and renewed political attention is needed., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Maternal mortality in Nepal dropped from 553 to 186 per 100 000 live births during 2000-2017 (66% decline). Neonatal mortality dropped from 40 to 21 per 1000 live births during 2000-2018 (48% decline). Stillbirths dropped from 28 to 18 per 1000 births during 2000-2019 (34% decline). Nepal outperformed other countries in these mortality improvements when adjusted for economic growth, making Nepal a 'success'. Our study describes mechanisms which contributed to these achievements., Methods: A mixed-method case study was used to identify drivers of mortality decline. Methods used included a literature review, key-informant interviews, focus-group discussions, secondary analysis of datasets, and validation workshops., Results: Despite geographical challenges and periods of political instability, Nepal massively increased the percentage of women delivering in health facilities with skilled birth attendance between 2000 and 2019. Although challenges remain, there was also evidence in improved quality and equity-of-access to antenatal care and childbirth services. The study found policymaking and implementation processes were adaptive, evidence-informed, made use of data and research, and involved participants inside and outside government. There was a consistent focus on reducing inequalities., Conclusion: Policies and programmes Nepal implemented between 2000 and 2020 to improve maternal and newborn health outcomes were not unique. In this paper, we argue that Nepal was able to move rapidly from stage 2 to stage 3 in the mortality transition framework not because of what they did, but how they did it. Despite its achievements, Nepal still faces many challenges in ensuring equal access to quality-care for all women and newborns., Competing Interests: Competing interests: Dr Punya and Dr Bibek are currently employed by the Government of Nepal. Dr Sharma was previously employed there. Their participation and insights have been invaluable to this report., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Objectives: Kenya 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., Methods: This 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., Results: Overall, 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%)., Conclusions: T. 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., Competing Interests: Stella Kepha reports financial support was provided by African Research Network for Neglected Tropical Diseases. The remaining authors have no competing interest to declare., (© 2024 The Authors.)

Background: The DeWorm3 trial is a multi-country study testing the feasibility of interrupting transmission of soil-transmitted helminths by community-wide mass drug administration (cMDA). Treatment coverage during cMDA delivery was validated by in-person coverage evaluation surveys (CES) after each round of treatment. A mobile phone-based CES was carried out in India when access to households was restricted during the COVID-19 lockdown., Methods: Two focus group discussions were conducted with the survey implementers to document their experiences of conducting phone-based CES via mobile-phone voice calls., Principal Findings: In the phone-based CES, only 56% of sampled households were reached compared to 89% during the in-person CES (89%). This was due to phone numbers being wrongly recorded, or calls being unanswered leading to a higher number of households that had to be sampled in order to achieve the sample size of 2,000 households in phone-based CES compared in-person CES (3,600 and 2,352 respectively). Although the phone-based CES took less time to complete than in person coverage evaluations, the surveyors highlighted the lack of gender representation among phone survey participants as it was mostly men who answered calls and were then interviewed. The surveyors also mentioned that eliciting responses to open-ended questions and confirming treatment compliance from every member of the household was challenging during phone based CES. These observations were confirmed by analysing the survey participation data which showed women's participation in CES was significantly lower in phone-based CES (66%) compared to in-person CES (94%) (Z = -22.38; p<0.01) and that a significantly higher proportion of households provided proxy responses in phone-based CES (51%) compared to in-person CES (21%) (Z = 20.23; p<0.01)., Conclusions: The phone-based CES may be a viable option to evaluate treatment coverage but issues such as participation bias, gender inclusion, and quality of responses will need to be addressed to optimize this methodology., Competing Interests: The authors have declared that no competing interests exist.
, (Copyright: © 2023 Aruldas et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objectives: With increasing mobile phone subscriptions, phone-based surveys are gaining popularity with public health programmes. Despite advantages, systematic exclusion of participants may limit representativeness. Similar to control programmes for neglected tropical diseases (NTDs), the DeWorm3 trial of biannual community-wide mass drug administration (MDA) for elimination of soil-transmitted helminth infection used in-person coverage evaluation surveys to measure the proportion of the at-risk population treated during MDA. Due to lockdown during the COVID-19 pandemic, a phone-based coverage evaluation survey was necessary, providing an opportunity for the current study to compare representativeness and implementation (including non-response) of these two survey modes., Design: Comparison of two cross-sectional surveys., Setting: The DeWorm3 trial site in Tamil Nadu, India, includes Timiri, a rural subsite, and Jawadhu Hills, a hilly, hard-to-reach subsite inhabited predominantly by a tribal population., Participants: In the phone-based and in-person coverage evaluation surveys, all individuals residing in 2000 randomly selected households (50 in each of the 40 trial clusters) were eligible to participate. Here, we characterise household participation., Results: Of 2000 households, 1780 (89.0%) participated during the in-person survey. Of 2000 households selected for the phone survey, 346 (17.3%) could not be contacted as they had not provided a telephone number during the census and 1144 (57.2%) participated. Smaller households, households with lower socioeconomic status and those with older, women or less educated household-heads were under-represented in the phone-based survey compared with censused households. Regression analysis revealed non-response in the phone-based survey was higher among households from the poorest socioeconomic quintile (prevalence ratio (PR) 2.3, 95% CI 2.0 to 2.7) and lower when heads of households had completed secondary school or higher education (PR 0.7, 95% CI 0.6 to 0.8)., Conclusions: Our findings suggest phone-based surveys under-represent households likely to be at higher risk of NTDs and in-person surveys are more appropriate for measuring MDA coverage within programmatic settings., Trial Registration Number: NCT03014167., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

Background: We examined fidelity and feasibility of implementation of COVID-19 preventive measures in schools, and explored associations between adherence to these measures and staff well-being, to inform policy on sustainable implementation and staff wellbeing., Methods: Surveys were conducted across 128 schools in England with 107 headteachers and 2698 staff-members with reference to autumn term 2020, examining school-level implementation of preventive measures, adherence, and teacher burnout (response rates for headteacher and staff surveys were 84% and 59%, respectively)., Results: The median number of measures implemented in primary and secondary schools was 33 (range 23-41), and 32 (range 22-40), respectively; most measures presented challenges. No differences were found regarding number of measures implemented by school-level socio-economic disadvantage. High adherence was reported for staff wearing face-coverings, staff regularly washing their hands, (secondary only) desks facing forwards, and (primary only) increased cleaning of surfaces and student hand-washing. Adherence to most measures was reported as higher in primary than secondary schools. Over half of school leaders and 42% (517/1234) of other teaching staff suffered from high emotional exhaustion. Higher teacher-reported school-wide adherence with measures was consistently associated with lower burnout for leaders and other teaching staff., Conclusions: Findings indicate a tremendous effort in implementing preventive measures and an urgent need to support investments in improving teacher wellbeing., (© 2022 The Authors. Journal of School Health published by Wiley Periodicals LLC on behalf of American School Health Association.)

Objectives: Investigate risk factors for SARS-CoV-2 infections in school students and staff., Methods: In the 2020/2021 school year, we administered polymerase chain reaction, antibody tests, and questionnaires to a sample of primary and secondary school students and staff, with data linkage to COVID-19 surveillance. We fitted logistic regression models to identify the factors associated with infection., Results: We included 6799 students and 5090 staff in the autumn and 11,952 students and 4569 staff in the spring/summer terms. Infections in students in autumn 2020 were related to the percentage of students eligible for free school meals. We found no statistical association between infection risk in primary and secondary schools and reported contact patterns between students and staff in either period in our study. Using public transports was associated with increased risk in autumn in students (adjusted odds ratio = 1.72; 95% confidence interval 1.31-2.25) and staff. One or more infections in the same household during either period was the strongest risk factor for infection in students and more so among staff., Conclusion: Deprivation, community, and household factors were more strongly associated with infection than contacts patterns at school; this suggests that the additional school-based mitigation measures in England in 2020/2021 likely helped reduce transmission risk in schools., Competing Interests: Declaration of competing interest The authors have no competing interests to declare., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: One of the most debated questions in the COVID-19 pandemic has been the role of schools in SARS-CoV-2 transmission. The COVID-19 Schools Infection Survey (SIS) aims to provide much-needed evidence addressing this issue., Objective: We present the study protocol and participation profile for the SIS study, aimed at assessing the role of schools in SARS-CoV-2 infection and transmission within school settings, and investigating how transmission within and from schools could be mitigated through the implementation of school COVID-19 control measures., Methods: SIS was a multisite, prospective, observational cohort study conducted in a stratified random sample of primary and secondary schools in selected local authorities in England. A total of 6 biobehavioral surveys were planned among participating students and staff during the 2020-2021 academic year, between November 2020 and July 2021. Key measurements were SARS-CoV-2 virus prevalence, assessed by nasal swab polymerase chain reaction; anti-SARS-CoV-2 (nucleocapsid protein) antibody prevalence and conversion, assessed in finger-prick blood for staff and oral fluid for students; student and staff school attendance rates; feasibility and acceptability of school-level implementation of SARS-CoV-2 control measures; and investigation of selected school outbreaks. The study was approved by the United Kingdom Health Security Agency Research Support and Governance Office (NR0237) and London School of Hygiene & Tropical Medicine Ethics Review Committee (reference 22657)., Results: Data collection and laboratory analyses were completed by September 2021. A total of 22,585 individuals-1891 staff and 4654 students from 59 primary schools and 5852 staff and 10,188 students from 97 secondary schools-participated in at least one survey. Across all survey rounds, staff and student participation rates were 45.2% and 16.4%, respectively, in primary schools and 30% and 15.2%, respectively, in secondary schools. Although primary student participation increased over time, and secondary student participation remained reasonably consistent, staff participation declined across rounds, especially for secondary school staff (3165/7583, 41.7% in round 1 and 2290/10,374, 22.1% in round 6). Although staff participation overall was generally reflective of the eligible staff population, student participation was higher in schools with low absenteeism, a lower proportion of students eligible for free school meals, and from schools in the least deprived locations (in primary schools, 446/4654, 9.6% of participating students were from schools in the least deprived quintile compared with 1262/22,225, 5.7% of eligible students)., Conclusions: We outline the study design, methods, and participation, and reflect on the strengths of the SIS study as well as the practical challenges encountered and the strategies implemented to address these challenges. The SIS study, by measuring current and incident infection over time, alongside the implementation of control measures in schools across a range of settings in England, aims to inform national guidance and public health policy for educational settings., International Registered Report Identifier (irrid): RR1-10.2196/34075., (©Katherine E Halliday, Patrick Nguipdop-Djomo, William E Oswald, Joanna Sturgess, Elizabeth Allen, Neisha Sundaram, Georgina Ireland, John Poh, Samreen Ijaz, Justin Shute, Ian Diamond, Emma Rourke, Fiona Dawe, Alison Judd, Taane Clark, W John Edmunds, Chris Bonell, Punam Mangtani, Shamez N Ladhani, Sinéad M Langan, James Hargreaves, COVID-19 Schools Infection Survey Study Group. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 10.11.2022.)

Background: There remains uncertainty about the epidemiology of SARS-CoV-2 among school students and staff and the extent to which non-pharmaceutical-interventions reduce the risk of school settings., Methods: We conducted an open cohort study in a sample of 59 primary and 97 secondary schools in 15 English local authority areas that were implementing government guidance to schools open during the pandemic. We estimated SARS-CoV-2 infection prevalence among those attending school, antibody prevalence, and antibody negative to positive conversion rates in staff and students over the school year (November 2020-July 2021)., Findings: 22,585 staff and students participated. SARS-CoV-2 infection prevalence among those attending school was highest during the first two rounds of testing in the autumn term, ranging from 0.7% (95% CI 0.2, 1.2) among primary staff in November 2020 to 1.6% (95% CI 0.9, 2.3) among secondary staff in December 2020. Antibody conversion rates were highest in the autumn term. Infection patterns were similar between staff and students, and between primary and secondary schools. The prevalence of nucleoprotein antibodies increased over the year and was lower among students than staff. SARS-CoV-2 infection prevalence in the North-West region was lower among secondary students attending school on normal school days than the regional estimate for secondary school-age children., Interpretation: SARS-CoV-2 infection prevalence in staff and students attending school varied with local community infection rates. Non-pharmaceutical interventions intended to prevent infected individuals attending school may have partially reduced the prevalence of infection among those on the school site., Funding: UK Department of Health and Social Care., Competing Interests: None declared., (Crown Copyright © 2022 Published by Elsevier Ltd.)

Malawi has successfully leveraged multiple delivery platforms to scale-up and sustain the implementation of preventive chemotherapy (PCT) for the control of morbidity caused by soil-transmitted helminths (STH). Sentinel monitoring demonstrates this strategy has been successful in reducing STH infection in school-age children, although our understanding of the contemporary epidemiological profile of STH across the broader community remains limited. As part of a multi-site trial evaluating the feasibility of interrupting STH transmission across three countries, this study aimed to describe the baseline demographics and the prevalence, intensity and associated risk factors of STH infection in Mangochi district, southern Malawi. Between October-December 2017, a community census was conducted across the catchment area of seven primary healthcare facilities, enumerating 131,074 individuals across 124 villages. A cross-sectional parasitological survey was then conducted between March-May 2018 in the censused area as a baseline for a cluster randomised trial. An age-stratified random sample of 6,102 individuals were assessed for helminthiasis by Kato-Katz and completed a detailed risk-factor questionnaire. The age-cluster weighted prevalence of any STH infection was 7.8% (95% C.I. 7.0%-8.6%) comprised predominantly of hookworm species and of entirely low-intensity infections. The presence and intensity of infection was significantly higher in men and in adults. Infection was negatively associated with risk factors that included increasing levels of relative household wealth, higher education levels of any adult household member, current school attendance, or recent deworming. In this setting of relatively high coverage of sanitation facilities, there was no association between hookworm and reported access to sanitation, handwashing facilities, or water facilities. These results describe a setting that has reduced the prevalence of STH to a very low level, and confirms many previously recognised risk-factors for infection. Expanding the delivery of anthelmintics to groups where STH infection persist could enable Malawi to move past the objective of elimination of morbidity, and towards the elimination of STH. Trial registration: NCT03014167., Competing Interests: The authors have declared that no competing interests exist.

Many sanitation interventions suffer from poor sustainability. Failure to maintain or replace toilet facilities risks exposing communities to environmental pathogens, yet little is known about the factors that drive sustained access beyond project life spans. Using data from a cohort of 1666 households in Kwale County, Kenya, we investigated the factors associated with changes in sanitation access between 2015 and 2017. Sanitation access is defined as access to an improved or unimproved facility within the household compound that is functional and in use. A range of contextual, psychosocial, and technological covariates were included in logistic regression models to estimate their associations with (1) the odds of sustaining sanitation access and (2) the odds of gaining sanitation access. Over two years, 28.3% households sustained sanitation access, 4.7% lost access, 17.7% gained access, and 49.2% remained without access. Factors associated with increased odds of households sustaining sanitation access included not sharing the facility and presence of a solid washable slab. Factors associated with increased odds of households gaining sanitation access included a head with at least secondary school education, level of coarse soil fragments, and higher local sanitation coverage. Results from this study can be used by sanitation programs to improve the rates of initial and sustained adoption of sanitation.

Since 2015, India has coordinated the largest school-based deworming program globally, targeting soil-transmitted helminths (STH) in ~250 million children aged 1 to 19 years twice yearly. Despite substantial progress in reduction of morbidity associated with STH, reinfection rates in endemic communities remain high. We conducted a community based parasitological survey in Tamil Nadu as part of the DeWorm3 Project-a cluster-randomised trial evaluating the feasibility of interrupting STH transmission at three geographically distinct sites in Africa and Asia-allowing the estimation of STH prevalence and analysis of associated factors. In India, following a comprehensive census, enumerating 140,932 individuals in 36,536 households along with geospatial mapping of households, an age-stratified sample of individuals was recruited into a longitudinal monitoring cohort (December 2017-February 2018) to be followed for five years. At enrolment, a total of 6089 consenting individuals across 40 study clusters provided a single adequate stool sample for analysis using the Kato-Katz method, as well as answering a questionnaire covering individual and household level factors. The unweighted STH prevalence was 17.0% (95% confidence interval [95%CI]: 16.0-17.9%), increasing to 21.4% when weighted by age and cluster size. Hookworm was the predominant species, with a weighted infection prevalence of 21.0%, the majority of which (92.9%) were light intensity infections. Factors associated with hookworm infection were modelled using mixed-effects multilevel logistic regression for presence of infection and mixed-effects negative binomial regression for intensity. The prevalence of both Ascaris lumbricoides and Trichuris trichiura infections were rare (<1%) and risk factors were therefore not assessed. Increasing age (multivariable odds ratio [mOR] 21.4, 95%CI: 12.3-37.2, p<0.001 for adult age-groups versus pre-school children) and higher vegetation were associated with an increased odds of hookworm infection, whereas recent deworming (mOR 0.3, 95%CI: 0.2-0.5, p<0.001) and belonging to households with higher socioeconomic status (mOR 0.3, 95%CI: 0.2-0.5, p<0.001) and higher education level of the household head (mOR 0.4, 95%CI: 0.3-0.6, p<0.001) were associated with lower odds of hookworm infection in the multilevel model. The same factors were associated with intensity of infection, with the use of improved sanitation facilities also correlated to lower infection intensities (multivariable infection intensity ratio [mIIR] 0.6, 95%CI: 0.4-0.9, p<0.016). Our findings suggest that a community-based approach is required to address the high hookworm burden in adults in this setting. Socioeconomic, education and sanitation improvements alongside mass drug administration would likely accelerate the drive to elimination in these communities. Trial Registration: NCT03014167., Competing Interests: The authors have declared that no competing interests exist.

We present a general framework which describes the systematic (binary) scenario of individuals either taking treatment or not for any reason, over the course of mass drug administration (MDA)-which we refer to as 'adherence' and 'non-adherence'. The probability models developed can be informed by observed adherence behaviour as well as employed to explore how different patterns influence the impact of MDA programmes, by the use of mathematical models of transmission and control. We demonstrate the interpretative value of the developed probability model employing a dataset collected in the TUMIKIA project, a randomised trial of deworming strategies to control soil-transmitted helminths (STH) by MDA conducted in coastal Kenya. We stratify our analysis by age and sex, although the framework which we introduce here may be readily adapted to accommodate other stratifications. Our findings include the detection of specific patterns of non-adherence in all age groups to varying extents. This is particularly apparent in men of ages 30+. We then demonstrate the use of the probability model in stochastic individual-based simulations by running two example forecasts for the elimination of STH transmission employing MDA within the TUMIKIA trial setting with different adherence patterns. This suggested a substantial reduction in the probability of elimination (between 23-43%) when comparing observed adherence patterns with an assumption of independence, with important implications for programmes. The results here demonstrate the considerable impact and utility of considering non-adherence on the success of MDA programmes to control neglected tropical diseases (NTDs)., Competing Interests: No authors have competing interests. RMA was a former non-executive director of GlaxoSmithKline.

We developed an electronic treatment register for the DeWorm3 Project, a cluster-randomised, controlled trial in Benin, India, and Malawi testing the feasibility of interrupting transmission of soil-transmitted helminths through community-wide mass drug administration. The electronic treatment register was designed in xlsform, deployed via the SurveyCTO mobile data collection platform, and implemented on smartphones running the Android operating system. The versatile system enables collection of census and treatment status information, facilitates data aggregation and visualisation, and permits real-time feedback loops during implementation of mass drug administration. Here we describe the system's design and use within the DeWorm3 Project and key features, and by sharing the register here, we hope our readers will further explore its use within their research and disease-control activities.

Background: Few studies have been done of patterns of treatment during mass drug administration (MDA) to control neglected tropical diseases. We used routinely collected individual-level treatment records that had been collated for the Tuangamize Minyoo Kenya Imarisha Afya (Swahili for Eradicate Worms in Kenya for Better Health [TUMIKIA]) trial, done in coastal Kenya from 2015 to 2017. In this analysis we estimate the extent of and factors associated with the same individuals not being treated over multiple rounds of MDA, which we term systematic non-treatment., Methods: We linked the baseline population of the TUMIKIA trial randomly assigned to receive biannual community-wide MDA for soil-transmitted helminthiasis to longitudinal records on receipt of treatment in any of the four treatment rounds of the study. We fitted logistic regression models to estimate the association of non-treatment in a given round with non-treatment in the previous round, controlling for identified predictors of non-treatment. We also used multinomial logistic regression to identify factors associated with part or no treatment versus complete treatment., Findings: 36 327 participants were included in our analysis: 16 236 children aged 2-14 years and 20 091 adults aged 15 years or older. The odds of having no treatment recorded was higher if a participant was not treated during the previous round of MDA (adjusted odds ratio [OR] 3·60, 95% CI 3·08-4·20 for children and 5·58, 5·01-6·21 for adults). For children, school attendance and rural residence reduced the odds of receiving part or no treatment, whereas odds were increased by least poor socioeconomic status and living in an urban or periurban household. Women had higher odds than men of receiving part or no treatment. However, when those with pregnancy or childbirth in the previous 2 weeks were excluded, women became more likely to receive complete treatment. Adults aged 20-25 years were the age group with the highest odds of receiving part (OR 1·41, 95% CI 1·22-1·63) or no treatment (OR 1·81, 95% CI 1·53-2·14)., Interpretation: Non-treatment was associated with specific sociodemographic groups and characteristics and did not occcur at random. This finding has important implications for MDA programme effectiveness, the relevance of which will intensify as disease prevalence decreases and infections become increasingly clustered., Funding: Bill & Melinda Gates Foundation, Joint Global Health Trials Scheme of the Medical Research Council, UK Department for International Development, Wellcome Trust, Children's Investment Fund Foundation, and London Centre for Neglected Tropical Diseases., (Copyright © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: Soil-transmitted helminths (STH) are intestinal parasites estimated to infect over 1.5 billion people. Current treatment programmes are aimed at morbidity control through school-based deworming programmes (targeting school-aged children, SAC) and treating women of reproductive age (WRA), as these two groups are believed to record the highest morbidity. More recently, however, the potential for interrupting transmission by treating entire communities has been receiving greater emphasis and the feasibility of such programmes are now under investigation in randomised clinical trials through the Bill & Melinda Gates Foundation funded DeWorm3 studies. Helminth parasites are known to be highly aggregated within human populations, with a small minority of individuals harbouring most worms. Empirical evidence from the TUMIKIA project in Kenya suggests that aggregation may increase significantly after anthelminthic treatment., Methods: A stochastic, age-structured, individual-based simulation model of parasite transmission is employed to better understand the factors that might induce this pattern. A simple probabilistic model based on compounded negative binomial distributions caused by age-dependencies in both treatment coverage and exposure to infection is also employed to further this understanding., Results: Both approaches confirm helminth aggregation is likely to increase post-mass drug administration as measured by a decrease in the value of the negative binomial aggregation parameter, k. Simple analytical models of distribution compounding describe the observed patterns well., Conclusions: The helminth aggregation that was observed in the field was replicated with our stochastic individual-based model. Further work is required to generalise the probabilistic model to take account of the respective sensitivities of different diagnostics on the presence or absence of infection.

Drinking water contamination is a frequent problem in developing countries and could be associated with bacterial pathogen carriage in feces. We evaluated the association between the risk of drinking water and bacterial carrier status in children younger than 5 years in a cross-sectional study conducted in 199 households from three Peruvian rural communities. Fecal samples from children were screened for pathogenic Aeromonas , Campylobacter , and Vibrio species, as well as for Enterobacteriaceae, including pathogenic Escherichia coli . The drinking water risk was determined using E. coli as an indicator of contamination. Nineteen (9.5%) children were colonized with pathogens and classified as carriers, all without diarrhea symptoms. Of 199 drinking water samples, 38 (19.1%) were classified as very high risk because of high fecal contamination (> 100 E. coli /100 mL). Shared-use water sources, daily washing of containers, and washing using only water were associated with higher prevalence of bacterial carriage, whereas there was no association between households reporting boiling and chlorination of water and carrier status. The prevalence of carriage in children exposed to very high-risk water was 2.82 (95% CI: 1.21-6.59) times the prevalence of those who consumed less contaminated water, adjusted by the water source and daily washing. Our results suggest that household drinking water plays an important role in the generation of carriers with diarrheal pathogens. Our findings also highlight the importance of interventions to ensure the safety of drinking water. Further studies are needed to validate the observed association and determine its significance with respect to diarrhea in the community.

Introduction: Few studies have simultaneously examined the role of sanitation conditions at the home, school, and community on soil-transmitted helminth (STH) infection. We examined the contribution of each domain that children inhabit (home, village, and school) to STH infection and estimated the association of STH infection with sanitation in each domain., Methods: Using data from 4,104 children from Kwale County, Kenya, who reported attending school, we used logistic regression models with cross-classified random effects to calculate measures of general contextual effects and estimate associations of village sanitation coverage (percentage of households with reported access to sanitation), school sanitation coverage (number of usable toilets per enrolled pupil), and sanitation access at home with STH infection., Findings: We found reported use of a sanitation facility by households was associated with reduced prevalence of hookworm infection but not with reduced prevalence of T. trichiura infection. School sanitation coverage > 3 toilets per 100 pupils was associated with lower prevalence of hookworm infection. School sanitation was not associated with T. trichiura infection. Village sanitation coverage > 81% was associated with reduced prevalence of T. trichiura infection, but no protective association was detected for hookworm infection. General contextual effects represented by residual heterogeneity between village and school domains had comparable impact upon likelihood of hookworm and T. trichiura infection as sanitation coverage in either of these domains., Conclusion: Findings support the importance of providing good sanitation facilities to support mass drug administration in reducing the burden of STH infection in children., Competing Interests: RMA was a nonexecutive director of GlaxoSmithKline, manufacturer of albendazole, during the period in which the paper was developed. He no longer holds this position but remains a stockholder. SJB is currently employed by the Bill & Melinda Gates Foundation (BMGF) but was employed by the London School of Hygiene & Tropical Medicine when TUMIKIA was designed and commenced. GlaxoSmithKline and BMGF played no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. All other authors declare no competing interests.

Background: As many countries with endemic soil-transmitted helminth (STH) burdens achieve high coverage levels of mass drug administration (MDA) to treat school-aged and pre-school-aged children, understanding the detailed effects of MDA on the epidemiology of STH infections is desirable in formulating future policies for morbidity and/or transmission control. Prevalence and mean intensity of infection are characterized by heterogeneity across a region, leading to uncertainty in the impact of MDA strategies. In this paper, we analyze this heterogeneity in terms of factors that govern the transmission dynamics of the parasite in the host population., Results: Using data from the TUMIKIA study in Kenya (cluster STH prevalence range at baseline: 0-63%), we estimated these parameters and their variability across 120 population clusters in the study region, using a simple parasite transmission model and Gibbs-sampling Monte Carlo Markov chain techniques. We observed great heterogeneity in R 0 values, with estimates ranging from 1.23 to 3.27, while k-values (which vary inversely with the degree of parasite aggregation within the human host population) range from 0.007 to 0.29 in a positive association with increasing prevalence. The main finding of this study is the increasing trend for greater parasite aggregation as prevalence declines to low levels, reflected in the low values of the negative binomial parameter k in clusters with low hookworm prevalence. Localized climatic and socioeconomic factors are investigated as potential drivers of these observed epidemiological patterns., Conclusions: Our results show that lower prevalence is associated with higher degrees of aggregation and hence prevalence alone is not a good indicator of transmission intensity. As a consequence, approaches to MDA and monitoring and evaluation of community infection status may need to be adapted as transmission elimination is aimed for by targeted treatment approaches.

Trial Registration: ClinicalTrials.gov NCT02397772., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: RMA was a nonexecutive director of GlaxoSmithKline during the course of the trial. SJB is currently employed by the Bill & Melinda Gates Foundation (BMGF), but was employed by the London School of Hygiene & Tropical Medicine when the study was designed and commenced and the baseline survey completed. GlaxoSmithKline and BMGF played no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. All other authors declare no competing interests.

The transmission soil transmitted helminths (STH) occurs via ingestion of or contact with infective stages present in soil contaminated with human faeces. It follows therefore that efforts to reduce faecal contamination of the environment should help to reduce risk of parasite exposure and improvements in water, sanitation and hygiene (WASH) are seen as essential for the long-term, sustainable control of STH. However, the link between WASH and STH is not always supported by the available evidence from randomised controlled trials, which report mixed effects of WASH intervention on infection risk. This review critically summarises the available trial evidence and offers an interpretation of the observed heterogeneity in findings. The review also discusses the implications of findings for control programmes and highlights three main issues which merit further consideration: intervention design, exposure assessment, and intervention fidelity assessment.

Background: School-based deworming programmes can reduce morbidity attributable to soil-transmitted helminths in children but do not interrupt transmission in the wider community. We assessed the effects of alternative mass treatment strategies on community soil-transmitted helminth infection., Methods: In this cluster-randomised controlled trial, 120 community units (clusters) serving 150 000 households in Kenya were randomly assigned (1:1:1) to receive albendazole through annual school-based treatment targeting 2-14 year olds or annual or biannual community-wide treatment targeting all ages. The primary outcome was community hookworm prevalence, assessed at 12 and 24 months through repeat cross-sectional surveys. Secondary outcomes were Ascaris lumbricoides and Trichuris trichiura prevalence, infection intensity of each soil-transmitted helminth species, and treatment coverage and costs. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02397772., Findings: After 24 months, prevalence of hookworm changed from 18·6% (95% CI 13·9-23·2) to 13·8% (10·5-17·0) in the annual school-based treatment group, 17·9% (13·7-22·1) to 8·0% (6·0-10·1) in the annual community-wide treatment group, and 20·6% (15·8-25·5) to 6·2% (4·9-7·5) in the biannual community-wide treatment group. Relative to annual school-based treatment, the risk ratio for annual community-wide treatment was 0·59 (95% CI 0·42-0·83; p<0·001) and for biannual community-wide treatment was 0·46 (0·33-0·63; p<0·001). More modest reductions in risk were observed after 12 months. Risk ratios were similar across demographic and socioeconomic subgroups after 24 months. No adverse events related to albendazole were reported., Interpretation: Community-wide treatment was more effective in reducing hookworm prevalence and intensity than school-based treatment, with little additional benefit of treating every 6 months, and was shown to be remarkably equitable in coverage and effects., Funding: Bill & Melinda Gates Foundation, the Joint Global Health Trials Scheme of the Medical Research Council, the UK Department for International Development, the Wellcome Trust, and the Children's Investment Fund Foundation., (Copyright © 2019 The Author(s). Published by Elsevier Ltd. This is an Open Access article under CC-BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Objective: To investigate, in Amhara, Ethiopia, the association between prevalence of active trachoma among children aged 1-9 years and community sanitation usage., Methods: Between 2011 and 2014, prevalence of trachoma and household pit latrine usage were measured in five population-based cross-sectional surveys. Data on observed indicators of latrine use were aggregated into a measure of community sanitation usage calculated as the proportion of households with a latrine in use. All household members were examined for clinical signs, i.e. trachomatous inflammation, follicular and/or intense, indicative of active trachoma. Multilevel logistic regression was used to estimate prevalence odds ratios (OR) and 95% confidence intervals (CI), adjusting for community, household and individual factors, and to evaluate modification by household latrine use and water access., Findings: In surveyed areas, prevalence of active trachoma among children was estimated to be 29% (95% CI: 28-30) and mean community sanitation usage was 47% (95% CI: 45-48). Despite significant modification (p < 0.0001), no pattern in stratified ORs was detected. Summarizing across strata, community sanitation usage values of 60 to < 80% and ≥ 80% were associated with lower prevalence odds of active trachoma, compared with community sanitation usage of < 20% (OR: 0.76; 95% CI: 0.57-1.03 and OR: 0.67; 95% CI: 0.48-0.95, respectively)., Conclusion: In Amhara, Ethiopia, a negative correlation was observed between community sanitation usage and prevalence of active trachoma among children, highlighting the need for continued efforts to encourage higher levels of sanitation usage and to support sustained use throughout the community, not simply at the household level.

Background: Globally, in 2010, approximately 1.5 billion people were infected with at least one species of soil-transmitted helminth (STH), Ascaris lumbricoides, Trichuris trichiura, hookworm (Ancylostoma duodenale and Necator americanus). Infection occurs through ingestion or contact (hookworm) with eggs or larvae in the environment from fecal contamination. To control these infections, the World Health Organization recommends periodic mass treatment of at-risk populations with deworming drugs. Prevention of these infections typically relies on improved excreta containment and disposal. Most evidence of the relationship between sanitation and STH has focused on household-level access or usage, rather than community-level sanitation usage. We examined the association between the proportion of households in a community with latrines in use and prevalence of STH infections among school-aged children., Methods: Data on STH prevalence and household latrine usage were obtained during four population-based, cross-sectional surveys conducted between 2011 and 2014 in Amhara, Ethiopia. Multilevel regression was used to estimate the association between the proportion of households in the community with latrines in use and presence of STH infection, indicated by > 0 eggs in stool samples from children 6-15 years old., Results: Prevalence of STH infection was estimated as 22% (95% CI: 20-24%), 14% (95% CI: 13-16%), and 4% (95% CI: 4-5%) for hookworm, A. lumbricoides, and T. trichiura, respectively. Adjusting for individual, household, and community characteristics, hookworm prevalence was not associated with community sanitation usage. Trichuris trichuria prevalence was higher in communities with sanitation usage ≥ 60% versus sanitation usage < 20%. Association of community sanitation usage with A. lumbricoides prevalence depended on household sanitation. Community sanitation usage was not associated with A. lumbricoides prevalence among households with latrines in use. Among households without latrines in use, A. lumbricoides prevalence was higher comparing communities with sanitation usage ≥ 60% versus < 20%. Households with a latrine in use had lower prevalence of A. lumbricoides compared to households without latrines in use only in communities where sanitation usage was ≥ 80%., Conclusions: We found no evidence of a protective association between community sanitation usage and STH infection. The relationship between STH infection and community sanitation usage may be complex and requires further study.

This study developed and validated a model for predicting the probability that communities in Amhara Region, Ethiopia, have low sanitation coverage, based on environmental and sociodemographic conditions. Community sanitation coverage was measured between 2011 and 2014 through trachoma control program evaluation surveys. Information on environmental and sociodemographic conditions was obtained from available data sources and linked with community data using a geographic information system. Logistic regression was used to identify predictors of low community sanitation coverage (< 20% versus ≥ 20%). The selected model was geographically and temporally validated. Model-predicted probabilities of low community sanitation coverage were mapped. Among 1,502 communities, 344 (22.90%) had coverage below 20%. The selected model included measures for high topsoil gravel content, an indicator for low-lying land, population density, altitude, and rainfall and had reasonable predictive discrimination (area under the curve = 0.75, 95% confidence interval = 0.72, 0.78). Measures of soil stability were strongly associated with low community sanitation coverage, controlling for community wealth, and other factors. A model using available environmental and sociodemographic data predicted low community sanitation coverage for areas across Amhara Region with fair discrimination. This approach could assist sanitation programs and trachoma control programs, scaling up or in hyperendemic areas, to target vulnerable areas with additional activities or alternate technologies., (© The American Society of Tropical Medicine and Hygiene.)

Objectives: To estimate the association between improved water and sanitation access and handwashing of mothers living in a peri-urban community of Lima, Peru., Methods: We observed 27 mothers directly, before and after installation of private, piped water and sewerage connections in the street just outside their housing plots, and measured changes in the proportion of faecal-hand contamination and hand-to-mouth transmission events with handwashing., Results: After provision of water and sewerage connections, mothers were approximately two times more likely to be observed washing their hands within a minute of defecation, compared with when they relied on shared, external water sources and non-piped excreta disposal (RR = 2.14, 95% CI = 0.99-4.62). With piped water and sewerage available at housing plots, handwashing with or without soap occurred within a minute after 48% (10/21) of defecation events and within 15 min prior to 8% (11/136) of handling food events., Conclusions: Handwashing increased following installation of private, piped water and sewerage connections, but its practice remained infrequent, particularly before food-related events. Infrastructural interventions should be coupled with efforts to promote hygiene and ensure access to water and soap at multiple on-plot locations convenient to mothers., (© 2014 John Wiley & Sons Ltd.)

Water safety plans (WSPs) are endorsed by the World Health Organization as the most effective method of protecting a water supply. With the increase in WSPs worldwide, several valuable resources have been developed to assist practitioners in the implementation of WSPs, yet there is still a need for a practical and standardized method of evaluating WSP effectiveness. In 2012, the Centers for Disease Control and Prevention (CDC) published a conceptual framework for the evaluation of WSPs, presenting four key outcomes of the WSP process: institutional, operational, financial and policy change. In this paper, we seek to operationalize this conceptual framework by providing a set of simple and practical indicators for assessing WSP outcomes. Using CDC's WSP framework as a foundation and incorporating various existing performance monitoring indicators for water utilities, we developed a set of approximately 25 indicators of institutional, operational, financial and policy change within the WSP context. These outcome indicators hold great potential for the continued implementation and expansion of WSPs worldwide. Having a defined framework for evaluating a WSP's effectiveness, along with a set of measurable indicators by which to carry out that evaluation, will help implementers assess key WSP outcomes internally, as well as benchmark their progress against other WSPs in their region and globally.

Objective: To document frequency of hygiene practices of mothers and children in a shantytown in Lima, Peru., Methods: Continuous monitoring over three 12-h sessions in households without in-house water connections to measure: (i) water and soap use of 32 mothers; (ii) frequency of interrupting faecal-hand contamination by washing; and (iii) the time until faecal-hand contamination became a possible transmission event., Results: During 1008 h of observation, 55% (65/119) of mothers' and 69% (37/54) of children's faecal-hand contamination events were not followed within 15 min by handwashing or bathing. Nearly 40% (67/173) of faecal-hand contamination events became possible faecal-oral transmission events. There was no difference in the time-until-transmission between mothers and children (P = 0.43). Potential transmission of faecal material to food or mouth occurred in 64% of cases within 1 h of hand contamination. Mean water usage (6.5 l) was low compared to international disaster relief standards., Conclusions: We observed low volumes of water usage, inadequate handwashing, and frequent opportunities for faecal contamination and possible transmission in this water-scarce community.

We assessed fecal contamination of drinking water in households in 2 peri-urban communities of Lima, Peru. We measured Escherichia coli counts in municipal source water and, within households, water from principal storage containers, stored boiled drinking water, and water in a serving cup. Source water was microbiologically clean, but 26 (28%) of 93 samples of water stored for cooking had fecal contamination. Twenty-seven (30%) of 91 stored boiled drinking water samples grew E. coli. Boiled water was more frequently contaminated when served in a drinking cup than when stored (P < 0.01). Post-source contamination increased successively through the steps of usage from source water to the point of consumption. Boiling failed to ensure safe drinking water at the point of consumption because of easily contaminated containers and poor domestic hygiene. Hygiene education, better point-of-use treatment and storage options, and in-house water connections are urgently needed.

Anopheles darlingi is the most important malaria vector in the Amazon basin of South America, and is capable of transmitting both Plasmodium falciparum and P. vivax. To understand the genetic structure of this vector in the Amazonian region of Peru, a simple polymerase chain reaction (PCR)-based test to identify this species of mosquito was used. A random amplified polymorphic DNA-PCR was used to study genetic variation at the micro-geographic level in nine geographically separate populations of An. darlingi collected in areas with different degrees of deforestation surrounding the city of Iquitos. Within-population genetic diversity in nine populations, as quantified by the expected heterozygosity (H(E)), ranged from 0.27 to 0.32. Average genetic distance (F(ST)) among these populations was 0.017. These results show that the nine studied populations are highly homogeneous, suggesting that strategies can be developed to combat this malaria vector as a single epidemiologic unit.