Vitamin A biomarkers were associated with α(1)-acid glycoprotein and C-reactive protein over the course of a human norovirus challenge infection.

Retinol binding protein (RBP) is used as a proxy for retinol in population-based assessments of vitamin A deficiency (VAD) for cost-effectiveness and feasibility. When the cut-off of < 0·7 µmol/l for retinol is applied to RBP to define VAD, an equivalence of the two biomarkers is assumed. Evidence suggests that the relationship between retinol and RBP is not 1:1, particularly in populations with a high burden of infection or inflammation. The goal of this analysis was to longitudinally evaluate the retinol:RBP ratio over 1 month of follow-up among fifty-two individuals exposed to norovirus (n 26 infected, n 26 uninfected), test whether inflammation (measured as α-1-acid glycoprotein (AGP) and C-reactive protein (CRP)) affects retinol, RBP and the ratio between the two and assess whether adjusting vitamin A biomarkers for AGP or CRP improves the equivalence of retinol and RBP. We found that the median molar ratio between retinol and RBP was the same among infected (0·68) and uninfected (0·68) individuals. AGP was associated with the ratio and RBP individually, controlling for CRP, and CRP was associated with both retinol and RBP individually, controlling for AGP over 1 month of follow-up. Adjusting for inflammation led to a slight increase in the ratio among infected individuals (0·71) but remained significantly different from the expected value of one. These findings highlight the need for updated recommendations from the WHO on a cut-off value for RBP and an appropriate method for measuring and adjusting for inflammation when using RBP in population assessments of VAD.

Quantifying Enteropathogen Contamination along Chicken Value Chains in Maputo, Mozambique: A Multidisciplinary and Mixed-Methods Approach to Identifying High Exposure Settings.

BACKGROUND: Small-scale poultry production is widespread and increasing in low- and middle-income countries (LMICs). Exposure to enteropathogens in poultry feces increases the hazard of human infection and related sequela, and the burden of disease due to enteric infection in children <5 y in particular is substantial. Yet, the containment and management of poultry-associated fecal waste in informal settings in LMICs is largely unregulated. OBJECTIVES: To improve the understanding of potential exposures to enteropathogens carried by chickens, we used mixed methods to map and quantify microbial hazards along production value chains among broiler, layer, and indigenous chickens in Maputo, Mozambique. METHODS: To map and describe the value chains, we conducted 77 interviews with key informants working in locations where chickens and related products are sold, raised, and butchered. To quantify microbial hazards, we collected chicken carcasses (n=75) and fecal samples (n=136) from chickens along the value chain and assayed them by qPCR for the chicken-associated bacterial enteropathogens C. jejuni/coli and Salmonella spp. RESULTS: We identified critical hazard points along the chicken value chains and identified management and food hygiene practices that contribute to potential exposures to chicken-sourced enteropathogens. We detected C. jejuni/coli in 84 (76%) of fecal samples and 52 (84%) of carcass rinses and Salmonella spp. in 13 (11%) of fecal samples and 16 (21%) of carcass rinses. Prevalence and level of contamination increased as chickens progressed along the value chain, from no contamination of broiler chicken feces at the start of the value chain to 100% contamination of carcasses with C. jejuni/coli at informal markets. Few hazard mitigation strategies were found in the informal sector. DISCUSSION: High prevalence and concentration of C. jejuni/coli and Salmonella spp. contamination along chicken value chains suggests a high potential for exposure to these enteropathogens associated with chicken production and marketing processes in the informal sector in our study setting. We identified critical control points, such as the carcass rinse step and storage of raw chicken meat, that could be intervened in to mitigate risk, but regulation and enforcement pose challenges. This mixed-methods approach can also provide a model to understand animal value chains, sanitary risks, and associated exposures in other settings. https://doi.org/10.1289/EHP11761.

Study design and rationale for the PAASIM project: a matched cohort study on urban water supply improvements and infant enteric pathogen infection, gut microbiome development and health in Mozambique.

INTRODUCTION: Despite clear linkages between provision of clean water and improvements in child health, limited information exists about the health impacts of large water infrastructure improvements in low-income settings. Billions of dollars are spent annually to improve urban water supply, and rigorous evaluation of these improvements, especially targeting informal settlements, is critical to guide policy and investment strategies. Objective measures of infection and exposure to pathogens, and measures of gut function, are needed to understand the effectiveness and impact of water supply improvements. METHODS AND ANALYSIS: In the PAASIM study, we examine the impact of water system improvements on acute and chronic health outcomes in children in a low-income urban area of Beira, Mozambique, comprising 62 sub-neighbourhoods and ~26 300 households. This prospective matched cohort study follows 548 mother-child dyads from late pregnancy through 12 months of age. Primary outcomes include measures of enteric pathogen infections, gut microbiome composition and source drinking water microbiological quality, measured at the child's 12-month visit. Additional outcomes include diarrhoea prevalence, child growth, previous enteric pathogen exposure, child mortality and various measures of water access and quality. Our analyses will compare (1) subjects living in sub-neighbourhoods with the improved water to those living in sub-neighbourhoods without these improvements; and (2) subjects with household water connections on their premises to those without such a connection. This study will provide critical information to understand how to optimise investments for improving child health, filling the information gap about the impact of piped water provision to low-income urban households, using novel gastrointestinal disease outcomes. ETHICS AND DISSEMINATION: This study was approved by the Emory University Institutional Review Board and the National Bio-Ethics Committee for Health in Mozambique. The pre-analysis plan is published on the Open Science Framework platform (https://osf.io/4rkn6/). Results will be shared with relevant stakeholders locally, and through publications.

Spatial heterogeneity of neighborhood-level water and sanitation access in informal urban settlements: A cross-sectional case study in Beira, Mozambique.

Rapid urbanization, resulting in population growth within informal settlements, has worsened exclusion and inequality in access to water and sanitation (WASH) services in the poorest and most marginalized communities. In this study, we describe the heterogeneity in water service satisfaction and WASH access in low-income, peri-urban neighborhoods of Beira, Mozambique, and examine whether this heterogeneity can be explained by distance to water distribution mains. Using spatial statistics and regression analyses, we identify spatial heterogeneity in household WASH access, as well as consumer-reported satisfaction with water services (services, pressure, quality, and sufficient quantity). We find that as distance from the water main increased, both access to an improved water source at the household and satisfaction with water pressure decreases, and water supply intermittency increases, controlling for household density and socioeconomic status. The odds of a household having access to a water source at the household or on the compound decreases with every 100-meter increase in distance from a water main pipe (odds ratio [OR] 0.87, 95% confidence interval [CI]: 0.82, 0.92). Satisfaction with water services also decreases with every 100-meter increase in distance from a water main pipe (OR: 0.80; 95% CI: 0.69, 0.94). Days of availability in the past week decreases by a factor of 0.22 for every 100-meter increase in distance from the water main (95% CI: -0.29, -0.15). Findings from this study highlight the unequal household access to water and sanitation in urban informal settlements, even within low-income neighborhoods. Describing this heterogeneity of access to water services, sanitation, and satisfaction-and the factors influencing them-can inform stakeholders and guide the development of infrastructural solutions to reduce water access inequities within urban settings.

Gut microbiome, enteric infections and child growth across a rural-urban gradient: protocol for the ECoMiD prospective cohort study.

INTRODUCTION: The functional consequences of the bacterial gut microbiome for child health are not well understood. Characteristics of the early child gut microbiome may influence the course of enteric infections, and enteric infections may change the composition of the gut microbiome, all of which may have long-term implications for child growth and development. METHODS AND ANALYSIS: We are conducting a community-based birth cohort study to examine interactions between gut microbiome conditions and enteric infections, and how environmental conditions affect the development of the gut microbiome. We will follow 360 newborns from 3 sites along a rural-urban gradient in northern coastal Ecuador, characterising enteric infections and gut microbial communities in the children every 3 to 6 months over their first 2 years of life. We will use longitudinal regression models to assess the correlation between environmental conditions and gut microbiome diversity and presence of specific taxa, controlling for factors that are known to be associated with the gut microbiome, such as diet. From 6 to 12 months of age, we will collect weekly stool samples to compare microbiome conditions in diarrhoea stools versus stools from healthy children prior to, during and after acute enteric infections, using principal-coordinate analysis and other multivariate statistical methods. ETHICS AND DISSEMINATION: Ethics approvals have been obtained from Emory University and the Universidad San Francisco de Quito institutional review boards. The findings will be disseminated through conference presentations and peer-reviewed journals.

Agricultural Detection of Norovirus and Hepatitis A Using Fecal Indicators: A Systematic Review.

Fresh-produce consumers may be at risk of pathogen infection due to fecal contamination of the agricultural environment. Indicators of fecal contamination may be used as a proxy to evaluate the potential presence of human pathogens, such as norovirus and hepatitis A, on agricultural samples. The objective of this systematic review was to determine whether the presence of human norovirus or hepatitis A was associated with microbial indicators in agricultural samples including fresh produce, equipment surfaces, and hands. Four databases (Embase, PubMed, Web of Science, and Agricola) were systematically searched and fifteen articles met inclusion and exclusion criteria. After data extraction, individual indicator-pathogen relationships were assessed using Cohen's Kappa coefficient. The level of agreement between norovirus with adenovirus was 0.09 (n = 16, 95% CI -0.05, 0.23), indicating poor agreement using Landis and Koch's criterion. Similarly, the Kappa coefficient between norovirus with E. coli (κ = 0.04, n = 14, 95% CI -0.05, 0.49) or total coliforms (κ = 0.03, n = 4, 95% CI -0.01, 0.02) was also poor. The level of agreement between hepatitis A with adenovirus (κ = -0.03, n = 3, 95% CI -0.06, 0.01) or fecal coliforms (κ = 0, n = 1, 95% CI 0, 0) was also poor. There were moderate relationships between hepatitis A with E. coli (κ = 0.49, n = 3, 95% CI 0.28, 0.70) and total coliforms (κ = 0.47, n = 2, 95% CI 0.47, 0.47). Based on these limited results, common indicator organisms are not strong predictors of the presence of norovirus and hepatitis A virus in the agricultural environment.