International Journal of Hygiene and Environmental Health

BackgroundBackyard poultry-raising is common in rural Bangladeshi households. Raising poultry contributes to fecal contamination of the domestic environment, increasing childrens exposure to enteric pathogens, including Campylobacter, which has been associated with child stunting. ObjectiveTo investigate the effectiveness of a behavior change communication and counseling intervention to encourage households to confine poultry outside of the household dwelling in a shed at night and improve poultry feces management. MethodsWe conducted a two-arm pre-post pilot study. Households in both arms received the behavior change communication and counseling intervention. Households in the subsidy arm also received ~23 USD for the construction of a poultry shed for nighttime housing. We administered a household survey and spot-check before and after intervention implementation among 37 subsidy and 42 non-subsidy households. ResultsAt endline, 58% of all households had a poultry shed (87% of subsidy and 33% of non-subsidy households) and the percentage of households confining all poultry outside the house the previous night was significantly higher at endline (33%) compared to baseline (2.5%) (prevalence difference [PD]: 30 percentage points [pp]; 95% CI: [19, 41]). Additionally, more households had no visible poultry feces piles inside the house compared to baseline (PD: 26pp 95% CI: [12, 41]), but there were no significant differences in the number of poultry feces piles in the courtyard or veranda. DiscussionOur intervention effectively encouraged households to confine poultry outside of household dwellings at night and to maintain an indoor living space free of poultry feces. Households were willing and able to construct a shed even without a subsidy. Households that received a subsidy were more likely to construct a shed. Future studies should assess if housing all poultry outside the household dwelling reduces childrens exposure to poultry feces enough to mitigate health risks associated with poultry ownership.

IntroductionWhile hygiene promotion is frequently included in sanitation programmes, few studies directly evaluate the effect of these interventions on hygiene outcomes. We assessed the effectiveness of a district-level Community-led Total Sanitation (CLTS) intervention with and without locally managed Care Groups (CG) on observed sanitation and hygiene behaviours in a rural area of Chiradzulu District, Malawi. MethodsThis was a controlled before-and-after trial with two intervention arms and a control group implemented in three sub-districts (also known as Traditional Authorities [TAs]) in Chiradzulu District, Malawi. Two TAs received CLTS, which included an additional low-intensity government-led hygiene promotion campaign. One TA received the standard CLTS intervention (CLTS group), and one received the same intervention but with additional sanitation and hygiene promotion delivered through local Care Groups (CLTS+CG group). The third TA served as the control group. Hygiene and child faeces disposal outcomes were measured by fieldworker direct observation in a purposively sampled subset of 96 to 140 households per arm enrolled in the main trial at baseline (June 2023) and at endline (May 2024). We estimated intervention effects on observed handwashing behaviour and safe child faeces disposal with hierarchical logistic regression models. ResultsIn our per protocol analysis, neither intervention was associated with differences in observed handwashing with soap compared to the control arm nor with differences in observed child faeces disposal. Additional analyses found that both interventions were associated with large increases in hand rinsing with water only compared to control groups (CLTS+CG group adjusted relative risk ratio [aRRR] = 2.80, CI = 1.81, 4.33; CLTS group aRRR = 1.76, CI = 1.10, 2.83). The CLTS+CG intervention was associated with a slight increase in hand rinsing compared to the CLTS only group (aRRR = 1.65, CI = 1.01, 2.69). ConclusionThe CLTS+CG and CLTS interventions were associated with an increase in hand rinsing at critical junctures but not handwashing with soap, suggesting that current hygiene programmes require further focus on soap access and use. Future research should investigate barriers to the availability and competing uses of soap in households. Both interventions did not increase safe child faeces disposal, though the sample size was small. Future research should investigate further integration of child faeces management into CLTS and CG behaviour change interventions.

BackgroundEnvironmental health services in healthcare facilities --including water, sanitation, hygiene, waste management, cleaning, and infection control--prevent disease and strengthen healthcare delivery. Yet environmental health service provision is inadequate in many low- and middle-income countries (LMICs). Despite the importance of monitoring and improving services, no comprehensive evidence map exists to describe global knowledge and gaps for action and improvement. The study objectives were to comprehensively catalog published literature on environmental health services in healthcare facilities in LMICs by service domain, study type, and relevance to policy and practice. MethodsWe conducted a systematic literature search in 2023 and performed an update in 2025. Through a title/abstract screening and tagging process, we developed a literature inventory that categorized studies by topic, design, and relevance to policy and practice objectives. ResultsThe literature inventory included 4,381 studies. Fifty-eight percent of the studies were baseline assessments of environmental health services, 36% involved formative research (e.g., qualitative methods), and 13% evaluated interventions or implementation strategies. Most studies (62%) examined hygiene at points of care, while 9% examined water and 6% sanitation. Twenty-seven percent of studies examined services in the context of the COVID-19 pandemic. ConclusionsThere is little evidence for effective interventions and implementation strategies to improve and sustain environmental health services, especially for water and sanitation services. Formative research on under-studied services can help policymakers and practitioners identify areas to prioritize investment and programming. Findings can inform the development of research agendas and practical guidelines for improving access to safe healthcare environments.

The prevalence of enteric pathogen detection in children in low-income countries climbs rapidly between birth and 6 months of age. Few studies have tested whether improved household environmental and behavioral hygiene conditions protects infants from exposure to enteric pathogens spread via unhygienic human and animal sanitation conditions, especially during this early window of infancy. This cross-sectional study utilized enrollment survey data among households with 6 month old infants in Kisumu, Kenya participating in the Safe Start cluster-randomized controlled trial to estimate associations between household water access and treatment, animal vectors, sanitation access, hand washing practices, supplemental feeding, and flooring, with the outcomes of caregiver-reported 7-day diarrhea prevalence and sum count of different enteric viruses, bacteria, and parasites pathogens in infant stool. Then, we tested whether household environmental hygiene and behavioral practices moderated associations between infant exposure outcomes and latrine access and domestic animal co-habitation. We found that reported handwashing after handling animals and before eating were strongly associated with lower risk of caregiver-reported diarrhea, while owning and co-habitating with animals (versus no animals), living in a household with vinyl covered dirt floors (versus finished floors), and feeding infants cow milk (versus no milk) were strongly associated with pathogen detection in infants. Caregiver handwashing after child or self-defecation moderated the relationship between shared sanitation (vs private) sanitation access and infant exposure to pathogens such that handwashing had the greatest benefit for preventing pathogen exposure of infants in households with private latrines. In the absence of handwashing, access to private sanitation posed no benefits over shared latrines for protecting infants from exposure. Our evidence highlights eliminating animal co-habitation, improving flooring, improving post-defecation and food-related handwashing, and improving safety of cow milk sources and/or safe household storage of milk as interventions to prevent enteric pathogen exposure of infants less than 6 months age. Key QuestionsO_ST_ABSWhat is already known?C_ST_ABSThe population prevalence of enteric infections and diarrhea climbs rapidly in the first year of life. Risk factors for pediatric infections include unhygienic human and animal sanitary conditions that introduce feces into the environment, as well as intermediate environmental and behavioral exposure pathways. Research examining the mitigating role of improved environmental and behavioral conditions in preventing infant exposure to human and animal sanitary conditions is limited. What are the new findings?Contact with domestic animals and feeding infants cow milk are leading risk factors for exposure to enteric pathogens by 6 months age in Kisumu, while handwashing after animal handling and before eating are protective factors against self-reported diarrhea. The benefits of access to a private improved latrine (versus shared) for protecting infants from pathogen exposure were conditional upon caregivers washing hands after defecation or child-defecation. What do the new findings imply?Interventions that keep animals out of infant living spaces and that improve food-related and post-defecation handwashing may be the most effective strategies for controlling the population prevalence of enteric infections in infants between birth and 6 months age in Kisumu and similar settings.

BackgroundDiarrheal disease is a leading cause of childhood morbidity and mortality globally. Household water, sanitation, and handwashing (WASH) interventions can reduce exposure to diarrhea-causing pathogens, but climatic factors may impact their effectiveness. Information about effect heterogeneity under different weather conditions is critical to intervention targeting. MethodsWe analyzed data from a trial in rural Bangladesh that compared child diarrhea prevalence between clusters that were randomized to different WASH interventions between 2012-2016 (NCT01590095). We matched temperature and precipitation measurements to households by geographic coordinates and date. We estimated prevalence ratios (PR) using generative additive models and targeted maximum likelihood estimation to assess the effectiveness of each WASH intervention under different environmental conditions. FindingsGenerally, WASH interventions most effectively prevented diarrhea during monsoon season, particularly following weeks with heavy rain or high temperatures. Compared to the control arm, WASH interventions reduced diarrhea by 51% (95% CI 33%-64%) following periods with heavy rainfall vs. 13% (95% CI -26%-40%) following periods without heavy rainfall. Similarly, WASH interventions reduced diarrhea by 40% (95% CI 16%-57%) following above-median temperatures vs. 17% (95% CI -38%-50%) following below-median temperatures. The influence of precipitation and temperature varied by intervention type; for precipitation, the largest differences in effectiveness were for the sanitation and combined WASH interventions. InterpretationWASH intervention effectiveness was strongly influenced by precipitation and temperature, and nearly all protective effects were observed during the rainy season. Future implementation of these interventions should consider local environmental conditions to maximize effectiveness. FundingBill & Melinda Gates Foundation; National Institute of Allergy and Infectious Diseases; National Heart, Lung, And Blood Institute; National Institute of General Medical Sciences; Stanford University School of Medicine; Chan Zuckerberg Biohub Research in Context PanelO_ST_ABSEvidence before this studyC_ST_ABSWe searched Google Scholar using the search terms "sanitation" OR "hygiene" OR "WASH" OR "water quality"; AND "heterogen*" OR "effect modif*"; AND "temperature" OR "precipitation" OR "rain*" OR "climate" OR "environmental"; AND "diarrhea" OR "enteric infection"; AND "risk" AND/OR "factors". In general, the effect modification of WASH interventions on diarrhea by weather is not well studied. One study in Ecuador investigated different relationships between rainfall, diarrhea, and unimproved sanitation and water sources. They found that unimproved sanitation was most strongly associated with elevated diarrhea after low rainfall, whereas unimproved water sources were most strongly associated with elevated diarrhea after heavy rainfall. In a similar setting in Ecuador, a separate study found that drinking water treatments reduced increases in diarrhea after heavy rainfall that followed dry periods, while sanitation and hygiene had no impact on the relationship between heavy rainfall and diarrhea. One study in Rwanda also found that high levels of runoff were protective against diarrhea only in households with unimproved toilets. In Bangladesh, one study found that access to tubewells was most effective at reducing childhood diarrhea in non-flood controlled areas. High heat can accelerate the inactivation of enteric pathogens by water chlorination, but no studies have examined how temperature influences the effectiveness of sanitation or hygiene interventions. No prior studies have estimated differences in WASH effectiveness under varying weather conditions within a randomized trial. Added value of this studyTo our knowledge, this is the first study to assess differences in household-level WASH intervention effectiveness by weather conditions in a randomized trial. We spatiotemporally matched individual-level data from a trial in rural Bangladesh to remote sensing data on temperature and precipitation and estimated differences in the effectiveness of WASH interventions to prevent childhood diarrhea under varying levels of these environmental factors. Implications of all the available evidenceWe found that WASH interventions were substantially more effective following periods with higher precipitation or higher temperatures. We observed the largest effect modification by precipitation for a sanitation intervention. This may be because compared to water and handwashing interventions, the sanitation intervention blocked more pathways through which enteric pathogens reach water, soil, and flies following heavy rainfall. In regions like Bangladesh, extreme weather is expected to become more common under climate change but WASH interventions might mitigate increases in childhood diarrhea due to climate change.

BackgroundThe rapid growth of the worlds urban population has contributed to the expansion of informal urban settlements in many cities across the world. In these settings, lack of safe sanitation combined with high population density and poverty contributes to heightened health risks for often vulnerable populations. The aim of this study was to evaluate the effect of a shared, onsite sanitation intervention on the nutritional status of children in Maputo, Mozambique. MethodsThe Maputo Sanitation (MapSan) trial was a controlled before-and-after study to evaluate the effect of a shared, onsite sanitation intervention on child health in Maputo, Mozambique. Here, we report the effects on childhood stunting, wasting and underweight, and height-for-age, weight-for-height and weight-for-age z-scores. Children were enrolled aged 1-48 months at baseline and outcomes were measured before and 12 and 24 months after the intervention, with concurrent measurement among children in a comparable control arm. The primary analysis was intention-to-treat. The trial was registered at ClinicalTrials.gov, number NCT02362932. ResultsWe enrolled 757 and 852 children in the intervention and control groups respectively. There was no evidence for an effect of the intervention on any outcome at 12 or 24 months of follow-up except for wasting where there was very weak evidence for an effect (adjusted prevalence ratio: 0.497; 95% CI: 0.22-1.11; p=0.09). In two exploratory analyses - one including only those children born into compounds post-intervention and a second excluding children in control compounds which had independently improved their sanitation facilities during follow-up - we found that stunting increased in the intervention group whilst wasting decreased. ConclusionsThis study contributes to the growing evidence on the role of sanitation in shaping child health outcomes in informal urban settlements. We found no evidence for an effect on stunting and weak evidence for an effect on wasting. More research is needed to understand how sanitation can reduce childhood undernutrition in complex urban environments.

IntroductionCommunity Led Total Sanitation (CLTS) has been used to increase sanitation coverage and use. However, robust evaluations of CLTS with and without other community-based interventions remain limited. We evaluated the effectiveness of standard CLTS and CLTS combined with a community-based "Care Group" model on sanitation and hygiene outcome compared to a non-intervention control in Chiradzulu District, rural Malawi. MethodsWe conducted a three-arm controlled before-and-after trial. One arm received standard CLTS, one received CLTS plus Care Group (CLTS+CG), and one served as control. Baseline and endline surveys were administered to 1,400 randomly sampled households. Difference-in-difference analysis assessed changes in sanitation and handwashing outcomes between May-June 2023 (baseline) and April-May 2024 (endline). ResultsAccess and use of sanitation facilities were generally high at baseline in all study arms. The primary outcome of the trial was access to a private sanitation facility of any quality. Both intervention arms were associated with improved odds of household having access to a private sanitation facility at endline compared to the control (CLTS: adjusted odds ratio [aOR] 3.11 (95% confidence interval [CI] 2.06-4.70); CLTS+CG: aOR 2.16 (CI 1.34-3.48)). However, there was no evidence that either intervention increased the odds of having a sanitation facility meeting quality standards for Sustainable Development Goals (SDG) 6. There was no observable difference between the two treatment arms on reported sanitation use. The odds of having a basic handwashing facility were higher in the CLTS+CG group versus control (aOR 2.62, CI 1.19-5.75) and CLTS+CG group versus standard CLTS group (aOR 2.89, CI 1.14-7.34); however, absolute increases in handwashing station coverage were limited. ConclusionThis study suggests that CLTS is unlikely to result in improvements in sanitation of quality required to meet SDG targets and has minimal impact on household level investment in hygiene facilities. Standard CLTS should no longer be the de facto rural sanitation policy.

BackgroundEnvironmental and Regulatory (ER) services, provided by local authorities, play a key role in public health protection. Food safety teams within ER services carry out regular food hygiene inspections, advice and education visits, and investigate foodborne disease outbreaks. Following the 2008 financial crisis, local authorities have faced substantial funding cuts. This study investigates the impact of local government expenditure reductions on food safety services. MethodsWe used fixed effects panel regression to analyse the effect of food safety expenditure reductions on food hygiene staffing levels, food hygiene interventions (e.g. inspection, sampling, advice and education), and the proportion of establishments rated food hygiene compliant. We also examined the effect of staff reductions on the number of interventions achieved and establishment compliance. ResultsA {pound}1 decrease in food safety expenditure per capita was associated with a 2% (95% CI 0.7% to 3.3%) decrease in staffing levels and a 1.7% (95% CI 0.2% to 3.3%) decrease in the number of interventions achieved per establishment. One-unit reduction in staff was associated with a 49.2% (95% CI 18.7%, 87.6%) decrease in the number interventions achieved. We found no evidence of an association between expenditure or staff levels and the proportion of compliant establishments. ConclusionSpending reductions negatively impact the capacity of food safety teams to provide key services. Reductions in food safety expenditure significantly impact food hygiene staff levels and service provision. This raises concerns about the capacity of food safety teams to operate and the potential for increased public risk of gastrointestinal infections.

Nontyphoidal Salmonella infection, or salmonellosis, typically presents with diarrhea, fever, and abdominal cramps and affects over 1 million people in the U.S. annually. Infants and young children are most susceptible to Salmonella infection, which can require hospitalization and lead to death. The vast majority of salmonellosis is foodborne and its incidence is highest during hot weather. This study used U.S. age-specific Salmonella surveillance data and geographic-specific temperature data to assess the relationship between summer season and Salmonella infection according to age group and geographic region. The Salmonella infection rate per 100,000 population was highest in infants (111.95), followed by children aged 1-4 (40.66), those aged 5-17 years (12.06), and adults 18 and older (10.84). Compared to winter months (December to February), an excess of approximately 8 infections per 100,000 infants for summer months (June to August) was observed. The corresponding excess was 15 per 100,000 infants for in the South. These findings suggest greater vulnerability among infants to future temperature increases.

Background SARS-CoV-2 genomic surveillance data remain limited in most low and middle-income countries (LMICs), resulting in significant gaps in the understanding of variant circulation and evolution. Wastewater-based epidemiology (WBE) presents a non-invasive, cost-effective, and population-representative surveillance approach that can complement clinical testing, particularly in densely populated urban informal settlements with limited healthcare access. This study aimed to pilot wastewater-based genomic surveillance as a multifaceted public health tool in Kenya. Methods A prospective study was conducted using wastewater samples collected from two WHO-validated environmental surveillance sites -- Eastleigh A (Kamukunji sub-county) and Mathare (Starehe sub-county) -- in Nairobi, Kenya, between December 2022 and October 2023. A total of 272 samples were collected using Moore swabs at a frequency of two to three times per week. Samples were concentrated using Nanotrap(R) Magnetic Virus Particles, and nucleic acid was extracted using the Qiagen QIAamp Viral RNA Mini Kit. SARS-CoV-2 was detected using RT-PCR (TaqPath COVID-19 CE-IVD RT-PCR Kit). Library preparation for whole-genome sequencing was performed using the Illumina COVIDSeq kit, and sequencing was conducted on the Illumina MiSeq platform. Bioinformatic analysis was performed using Terra.bio and RStudio, and phylogenetic analysis included sequences abstracted from GISAID. Results Of 272 samples, 238 (87.5%) tested positive with a cycle threshold (Ct) value of less than 36. Genomic analysis of 181 sequences identified Omicron as the predominant circulating variant, detected in 59% of samples. Other variants included XBB (16%), XBB.2.3(10%), XBB.1.9.X (5%), and additional minor variants. These findings were concordant with clinical sequencing data from Kenya over the same period. Conclusions Wastewater-based genomic surveillance reliably reflected SARS-CoV-2 variant trends observed in clinical data. This approach provides early signals of variant emergence and evolution, offering a cost-effective complement to clinical surveillance in resource-limited settings.

BackgroundChildhood lead exposure is prevalent worldwide including low- and middle-income countries (LMICs). Structured screening and prevention programs to address pediatric lead exposure are largely absent in these settings. Adapted interventions are needed to close this implementation gap in an urban African context. This paper describes the protocol for the Lead Exposure Intervention Program (LEIP), which aims to adapt, pilot, and evaluate a pediatric lead exposure screening and risk-reduction protocol in Nairobi, Kenya. MethodsLEIP is a multi-phase, hybrid type 3 implementation-effectiveness study. Phase 1 is a formative one-arm study leveraging an existing mother-child cohort and stakeholder-led tools adaptation to pilot a program comprising blood lead level (BLL) screening with a lead risk survey and tailored caregiver risk reduction messaging. Phase 2 is a randomized trial in public sector clinics. In this phase, approximately 1,500 children will be screened to identify 100 with elevated BLL ([≥]5 {micro}g/dL) for enrollment, who will then be randomized 1:1 to receive either clinic-only risk-reduction messaging or the same clinic-based messaging plus a home visit for environmental assessment and additional tailored messaging. Follow-up at 3 and 9 months will assess caregiver recall of key messages and adoption of recommended exposure-reduction behaviors, as well as changes in child BLL. Phase 3 involves qualitative interviews with caregivers and key stakeholders to identify multi-level barriers and facilitators to intervention uptake. Quantitative and qualitative findings will be integrated to inform refinements for scale-up. DiscussionThis study represents a critical opportunity to develop and evaluate an adaptive, screening-based lead exposure intervention tailored to the urban LMIC context. By incorporating implementation science principles and stakeholder-driven design, LEIP is well-positioned to inform scalable national and regional approaches. The inclusion of both quantitative and qualitative components enhances the protocols ability to capture multilevel dynamics of uptake, fidelity, and sustainability, and generate actionable insights for future large-scale implementations. Trial RegistrationRegistered on ClinicalTrials.gov (NCT07401251)

BackgroundTyphoid fever is a major public health issue in low- and middle-income countries. It is transmitted through fecally contaminated food or water and thus improving water, sanitation, and hygiene (WASH) is considered key to its control. We sought to quantify the association between WASH and typhoid fever. MethodsWe updated a previous review by including new findings from the literature indexed in Web of Science, Embase, and PubMed. We kept the search terms, typhoid and case-control, consistent with the previous review. We assessed the risk of bias using the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I). We categorized WASH exposures according to the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene (JMP) classification. We conducted a Bayesian random-effects meta-analysis of odds ratios (ORs) extracted from the studies without a critical risk of bias. FindingsWe identified 25 eligible articles including 19 articles from the previous review. Pooled ORs indicated limited hygiene (OR = 2.26, 95% CrI: 1.38 to 3.64), untreated water (OR = 2.21, 95% CrI: 1.53 to 3.48) and using surface water (OR = 2.16, 95% CrI: 1.24 to 3.60) increased odds of culture-confirmed typhoid fever. On the other hand, basic hygiene (OR = 0.6, 95% CrI: 0.38 to 0.97) and treated water (OR = 0.62, 95% CrI: 0.41 to 0.89) reduced odds of culture-confirmed typhoid fever. ConclusionOur analyses updated quantitative evidence of association between WASH and typhoid fever. Our study findings will be useful to infer actionable insights on the most effective ways to control typhoid fever in low- and middle-income countries. Our analyses also offer a possibility to leverage JMP WASH data to explore potential burden of typhoid fever. Systematic review registrationPROSPERO 2021 CRD42021271881 Author SummaryTyphoid fever is a major public health issue in the low- and middle-income countries. It is transmitted through fecally contaminated food or water and thus improving water, sanitation, and hygiene (WASH) is considered key to its control. We quantified the association between WASH and typhoid fever through a systematic review of the case-control studies and meta-analyses of extracted odds ratios (ORs). We categorized WASH exposures according to the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene (JMP). We used a Bayesian random-effects model to account for the heterogeneity of studies that were conducted at different times and places, and adjusted potential bias differently. Pooled ORs indicated that limited hygiene (OR = 2.26, 95% CrI: 1.38 to 3.64), untreated water (OR = 2.21, 95% CrI: 1.53 to 3.48) and using surface water (OR = 2.16, 95% CrI: 1.24 to 3.60) increased odds of typhoid fever. On the other hand, basic hygiene (OR = 0.6, 95% CrI: 0.38 to 0.97) and treated water (OR = 0.62, 95% CrI: 0.41 to 0.89) reduced odds of culture-confirmed typhoid fever. Our analyses updated evidence for the association between WASH and typhoid fever. The updated evidence strongly supports that improved WASH such as improved water source, water treatment, and basic hygiene will help reduce typhoid fever in low- and middle-income countries. By linking WASH exposures to new JMP WASH categories our analyses also offer a possibility to leverage JMP WASH data sets to explore potential burden of typhoid fever.

IntroductionThe coverage of access to basic drinking water and sanitation facilities in India was estimated to be 93% and 60%, respectively, in 2017. The monitoring of the burden of diarrhoeal illnesses, especially in children, remains important to assess the impact of the expansion of water and sanitation (WaSH) in the Indian setting. This study aimed to estimate the burden of diarrhoea in an established longitudinal pediatric cohort in an urban settlement of Vellore in South India. MethodsThe Surveillance for Enteric Fever in India (SEFI) cohort established in an urban settlement of Vellore, south India, enrolled 6760 children aged between 6 months and 15 years. The cohort was followed up for typhoid and paratyphoid fever between 2017 and 2019. Field research assistants contacted caregivers of these children weekly to elicit any diarrhoeal illness in the child in the preceding week. As a part of SEFI environmental surveillance, drinking water samples from the study households were tested for coliforms. Sociodemographic characteristics, including source of drinking water, sanitation and hygiene practices, were collected. Incidence of diarrhoea was estimated and expressed as the number of diarrhoeal episodes over child-years of observation (CYO). Poisson regression analysis was performed to identify predictors of diarrhoeal episodes. ResultsThe estimated incidence of diarrhoea in the 6501 children followed up between November 1, 2017, and October 31, 2019, was 31.1 episodes per 100 CYO, with children in the age group of 6 months and <5 years having a higher incidence of diarrhoea than those aged between 5 and 15 years (58.6 versus 22 episodes per 100 CYO). Of the 6467 children with information on WaSH available, 5812 (89.9%) used the public distribution system for drinking water. Of the 1804 drinking water samples tested, 1346 (74.6%) had coliform counts >10,000/100 mL. Only about one-third of the cohort (n=2293, 35.5%) lived in households with access to improved sanitation. Multivariable analysis showed that children aged <2 years, residing in crowded settlements, using the public distribution system for drinking water and from households with poor hygiene practices related to excreta disposal of under-five children had a higher risk for diarrhoea. ConclusionApproximately 8 in 10 children in urban Vellore lack access to safely managed drinking water, and thereby, are at a high risk for diarrheal illnesses, especially in the under-5 children. With rapidly expanding urbanisation in the Indian setting, it is pertinent that emphasis be laid on robust planning and provision of safely managed water and sanitation.

Background: Beaches are popular summertime destinations in Canada. However, they can be affected by specific fecal pollution sources, increasing the risk of recreational water illness. Objectives: This study was conducted to determine the risks of acute gastrointestinal illness (AGI) among Canadian beachgoers and to evaluate the influence of different fecal indicator bacteria (FIB) and other water quality measures on assessing these risks. Methods: In a prospective cohort design, beachgoers were recruited at sites across Canada from 2023 to 2025. Sociodemographic characteristics and exposures were determined through an on-site survey, with a 7-day follow-up survey to determine risks of AGI. Bayesian mixed-effects logistic regression models were fitted to evaluate the effects of an ordinal water contact variable (no contact, minimal contact, body immersion, and swallowed water) on the incident risk of AGI, with an interaction included for water quality indicators. The levels of six FIB and water quality measures were assessed: Escherichia coli, enterococci DNA, three microbial source tracking DNA markers (human HF183/BacR287, human mitochondria, seagull Gull4), and turbidity. Results: A total of 4085 participants were recruited, with 67.6% completing the follow-up survey. The overall incident risk of AGI was 2.6%. Both swallowing water and body immersion increased AGI risks compared to no water contact: median of 20 excess cases (95% Credible Interval [CrI]: 4, 64) and 5 excess cases (95% CrI: 1, 19) of AGI predicted per 1000 beachgoers, respectively. Escherichia coli and seagull DNA marker levels were associated with AGI among those who had water contact, particularly among those who reported swallowing water. Discussion: While the overall burden of AGI due to beach water contact in Canada was low, increased risks are associated with E. coli levels particularly among those who swallow water. This could be related to fecal contamination from seagulls. However, there is substantial uncertainty in the predicted effect sizes.

IntroductionRural sanitation deficits in the United States represent an important source of non-point source pollution and may present risks to public health. We propose an interrupted time series analysis to measure the effect of a town-wide sanitation expansion program on the release of pathogens to the environment. This work is expected to yield valuable insight into the potential for rural sanitation improvements to reduce pathogen releases and support public health and well-being. MethodsWe will conduct a longitudinal baseline study including quantitative measurement of key enteric pathogens and fecal indicator bacteria adjacent to households lacking adequate sanitation. As households connect to a new sewerage system serving the entire community, longitudinal household sampling will continue until crossover is complete. We will include concurrent comparison sites with existing appropriate sanitation as well as sites never receiving the intervention to monitor secular trends in pathogen releases during the study period. AnalysisWe will compare the concentration of culturable E. coli in the environment pre- and post-intervention using a time series regression analysis suitable for an interrupted time series. We will couple pathogen measurements with quantitative microbial risk assessment to estimate the potential effect of the intervention on infection risks via key exposure pathways. A linked pre-post survey will focus on self-reported quality of life measures among households connecting to the system. Ethics and disseminationInformed consent will be obtained prior to data collection, with participants informed of study details and risks. Participation is completely voluntary, and identifiable data will be securely and separately stored from all other data. Each household will be offered a summary of their site-specific data. Deidentified results will be shared with the community in a public forum and published in peer-reviewed journals. Strengths and Limitations of this StudyO_LIThis study utilizes both molecular and culture-based environmental sampling with structured household and observational surveys to carefully assess the effects of a community-wide sanitation system on environmental contamination, infection risk, and well-being. C_LIO_LITo address potential confounding due to secular trends and/or weather-related events, we plan to include at least 10 comparison sites with existing improved sanitation C_LIO_LIinfrastructure and 10 sites with poor sanitation infrastructure not receiving the intervention during the study period. C_LIO_LIBias will be reduced by defining enteric pathogen targets and the main statistical models prior to analysis. C_LIO_LIAlthough we will adjust for external trends such as temperature and rainfall, the design of an interrupted time series lacks a randomized control group, limiting the ability to fully isolate the intervention effect. C_LIO_LIVoluntary participation and required utility fees may lead to selection bias, and survey responses may be influenced by social desirability or courtesy bias. We aim to mitigate this through community engagement, confidentiality assurances, and validating survey responses with environmental testing. C_LI

Transmission of Cryptosporidium can occur via contaminated food or water, contact with animals or other people. Exposures are often identified from outbreak investigations, but sources for sporadic disease and pathways to infection are still unclear. The aim of this review is to consolidate the literature to describe exposures associated with human cryptosporidiosis in industrialised countries. Methods followed the recommendations made in the Cochrane Handbook for Systematic Reviews of Interventions. Three steps were used to identify the literature including electronic database searching using PubMed, Scopus and Web Of Science; reference list trawling; and an exploration of the grey literature. Quality was assessed using the Newcastle-Ottawa Scale. Screening of results was undertaken by two reviewers and data extracted using a standardised form. A narrative summary presented. Papers were included if they reported on sporadic cases and were published between 2008 and 2018. Exposures were grouped into pathways. After full-text screening, eight articles (comprising 11 studies) were included, and seven (comprising 10 studies) were suitable for further synthesis. None of the identified grey literature was included. Four studies described case-control methods, two were case-case studies and one cross-sectional. Study year ranged from 1999 to 2017 and the studies were conducted in five, large countries in three continents: Europe (UK and the Netherlands), North America (USA, Canada), and Australia. Included papers investigated water and animal exposures most frequently. Recreational water was not a major source of sporadic illness in this review. The person-to-person pathway represented the most consistent finding, with all three studies reporting on contact with a symptomatic individual demonstrating correlations between exposure and disease. This applied particularly to the home environment, which is increasingly understood to be a significant setting for spread of Cryptosporidium infection. Further work on this would help support public health messaging on preventing spread of disease at home. Systematic review registration: PROSPERO number CRD42017056589.

Behavior plays is critical role in global health research and practice. Indirect measures of behavior, such as surveys, are easier to implement and require fewer resources, and therefore are often favored over more direct measures, such as behavioral observation. Despite these advantages, indirect measures can also produce unreliable data. Direct measures, such as behavioral observation, produce much more reliable data, yet are often underutilized in global health. Moreover, when direct measures are used the descriptions of the methods related to data collection are often minimal making it difficult for others to replicate what was done. This paper is a case study outlining the data collection methods used in an epidemiological study that evaluated the pathways of infants exposure to Campylobacter spp. in rural Ethiopia. Included are details on the selection of outcome or target behaviors, the data collection software, the training of enumerators, and quality control measures as well as samples of the data produced through these data collection methods.

PurposeThe Population-based Microbiome Research Core (PMRC) is an expandable and longitudinal research core infrastructure to support the study of the human microbiome within the context of environmental, sociodemographic, and health factors. Broadly, the purpose of this infrastructure is to provide new insights into how human-environment interactions affect health through its influence on the composition and function of the microbiome. The PMRC was established as an ancillary study of the Survey of Health of Wisconsin (SHOW) and serves as a platform for ancillary studies, ongoing follow-up of the cohort, and expansion of the microbiome biorepository. ParticipantsThe study recruited adult participants who had previously participated in SHOWs Wisconsin Microbiome Study (WMS). Over 59% of the eligible WMS participants agreed to provide a repeat stool sample and household samples including dust, high touch surface swabs and outside soil. Findings to datePMRC includes 323 individuals; the majority (96%) were over the age of eighteen, white (84%), urban (75%), and lived in their homes for over one year (92%). Overall, 97% of participants completed the questionnaire and household high-touch surface swab collection, and 93% and 94% completed dust and stool collection, respectively. Soil samples were collected for 86% of all participant homes. Future plansSample protocols developed for the PMRC offer a unique framework for future household-based microbiome research. This infrastructure can support the generation of new knowledge on the role of the home environment in relation to the human microbiome and identify new opportunities for intervention research.

BackgroundTens of millions of agricultural workers are directly exposed to pesticides through handling pesticide products, mostly in developing countries. Systematic data synthesis on the genotoxic consequences of such occupational exposures and their human health risks in agricultural settings is required in Arab countries. We aim to conduct a systematic review and, if possible, a meta-analysis to review published literature about the genotoxicity of occupational pesticide exposures in Arab countries, with the objectives of characterising the (1) prevalence rates of genotoxic pesticide exposures, (2) extent of genotoxic insults, (3) attributed risk factors, and (4) preventive measures against pesticide-induced genotoxic effects detectable by biomonitoring. MethodsThe research will follow the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) statement. A comprehensive search will be conducted in November 2022 in the electronic databases PubMed (NLM), EMBASE (Elsevier), Web of Science (Clarivate), Scopus (Elsevier), and Agricola in addition to WHO Index Medicus for the Eastern Mediterranean (IMEMR). The search will be performed without any restrictions for publication years. A filter for English and Arabic language will be applied. The systematic search will include agricultural workers over the age of 18 years, located in Arabic speaking countries of the Middle East and North Africa (MENA) region, occupationally exposed to pesticides inducing genotoxic insult detectable by biomonitoring. Records identified in the search will be imported into the systematic review tool Covidence for blinded screening and selection by two reviewers independently. The reviewers will then extract data and conduct risk of bias assessment using the Navigation Guide RoB tool and the RoB-SPEO tool. The results will be synthetized narratively in summary tables, and, if findings allow, meta-analysis, including subgroup and sensitivity analysis, will be conducted on the prevalence of genotoxic pesticide exposures, and on the effect size of risk factors. The systematic review methodology does not require ethics approval. DiscussionThe systematic review will consider various types of pesticide exposures and genotoxicity biomarker assays to determine prevalence and extent of such occupational genotoxic insults, the correlation between genetic damage and various risk factors, e.g. work conditions, types of pesticides, environmental exposure routes, and the applied preventive measures. The review will provide gap-filling information about genotoxic pesticide exposures of agricultural workers in the local context, as well as it will contribute to our general knowledge on pesticide genotoxicity. Systematic review registrationPROSPERO registration number: CRD42022314453.

AbstractO_ST_ABSBackgroundC_ST_ABSOrganophosphate and pyrethroid insecticides can affect childrens neurodevelopment and increase inflammation. Limited evidence exists among adolescents and on whether inflammation may mediate pesticide-neurobehavior associations. We examined the associations between insecticide metabolite concentrations and neurobehavior among adolescents in Ecuadorian agricultural communities. MethodsWe included 520 participants aged 11-17 years. We measured urinary insecticide metabolites (mass spectrometry) and neurobehavior (NEPSY-II). Associations were adjusted for socio-demographic and anthropometric characteristics. The associations of insecticide mixtures with neurobehavior were evaluated using PLS regression, and mediation by inflammatory biomarkers (TNF-, IL-6, CRP, SAA, sICAM-1, sVCAM-1 and sCD-14) was conducted. ResultsAmong organophosphates, para-nitrophenol (PNP) and 3,5,6-Trichloro-2-pyridinol (TCPy) were inversely associated with Social Perception (score difference per 50% increase [{beta}50%] = -0.26 [95%CI: - 1.07, -0.20] and -0.10 [-0.22, 0.01], respectively). PNP and TCPy also had significant inverse associations with Attention/Inhibitory Control at concentrations >60th percentile ({beta}50%= -0.26 [95%CI: -0.51, -0.01] and {beta}50%= -0.22 [95%CI: -0.43, -0.00], respectively). The pyrethroid, 3-phenoxybenzoic acid (3-PBA), was inversely associated with Language ({beta}50% = -0.13 [95%CI: -0.19, -0.01]) and had a negative quadratic association with Attention/Inhibitory Control. The neonicotinoid 5-Hydroxy imidacloprid (OHIM) was positively associated with Memory/Learning ({beta}50% = 0.20 [95%CI: 0.04, 0.37]). Mixtures of all insecticides were significantly negatively related to all domains, except for Memory/Learning, which was positively associated. No mediation by inflammatory markers on these associations was observed. ConclusionsConcurrent organophosphate, pyrethroid, and the mixtures of all metabolites were associated with lower performance in all domains except for Memory/Learning. Neonicotinoids were positively associated with Memory/Learning and Social Perception scores.