Global Enteric Multicenter Study Research Articles

The effect of acute malnutrition on enteric pathogens, moderate-to-severe diarrhoea, and associated mortality in the Global Enteric Multicenter Study cohort: a post-hoc analysis

SummaryBackgroundHost vulnerabilities associated with acute malnutrition could facilitate the ability of specific enteric pathogens to cause diarrhoea and associated mortality. Using data from the Global Enteric Multicenter Study, we assessed whether acute malnutrition modifies the association between common enteric pathogens and moderate-to-severe diarrhoea, and whether associations between enteric pathogens and death were modified by acute malnutrition.MethodsChildren with moderate-to-severe diarrhoea and age-matched and community-matched controls were included in this post-hoc analysis if their mid-upper arm circumference had been measured and if they were older than 6 months of age. Acute malnutrition was defined as mid-upper arm circumference below 12·5 cm, capturing both severe acute malnutrition (<11·5 cm) and moderate acute malnutrition (≥11·5 cm and <12·5 cm). We tested whether acute malnutrition modified associations between enteric pathogens and moderate-to-severe diarrhoea in conditional logistic regression models. Among children with moderate-to-severe diarrhoea, Cox proportional hazards regression evaluated the modifying effect of acute malnutrition on the relationship between pathogens and 60-day fatality rate.FindingsThe age, site, and co-infection adjusted odds ratios (aORs) for moderate-to-severe diarrhoea associated with typical enteropathogenic Escherichia coli among children aged 6–11 months was 2·08 (95% CI 1·14–3·79) in children with acute malnutrition, and 0·97 (0·77–1·23) in children with better nutritional status, compared with healthy controls. Enterotoxigenic E coli producing heat-stable toxin among children aged 12–23 months also had a stronger association with moderate-to-severe diarrhoea in children with acute malnutrition (aOR 7·60 [2·63–21·95]) than among similarly aged children with better nutritional status (aOR 2·39 [1·76–3·25]). Results for Shigella spp, norovirus, and sapovirus suggested they had a stronger association with moderate-to-severe diarrhoea than other pathogens among children with better nutritional status, although Shigella spp remained associated with moderate-to-severe diarrhoea in both nutritional groups. 92 (64%) of 144 children with moderate-to-severe diarrhoea who died had acute malnutrition. Pathogen-specific 60-day fatality rates for all pathogens were higher among children with acute malnutrition, but no individual pathogen had a significantly larger increase in its relative association with mortality.InterpretationAcute malnutrition might strengthen associations between specific pathogens and moderate-to-severe diarrhoea. However, the strong link between acute malnutrition and mortality during moderate-to-severe diarrhoea in children is not limited to specific infections, and affects a broad spectrum of enteric pathogens. Interventions addressing acute malnutrition could be an effective way to lower the mortality of both childhood malnutrition and diarrhoea.FundingThe Bill & Melinda Gates Foundation.

Factors associated with typical enteropathogenic Escherichia coli infection among children

Typical enteropathogenic Escherichia coli (tEPEC) infection is a major cause of diarrhoea and contributor to mortality in children <5 years old in developing countries. Data were analysed from the Global Enteric Multicenter Study examining children <5 years old seeking care for moderate-to-severe diarrhoea (MSD) in Kenya. Stool specimens were tested for enteric pathogens, including by multiplex polymerase chain reaction for gene targets of tEPEC. Demographic, clinical and anthropometric data were collected at enrolment and ~60-days later; multivariable logistic regressions were constructed. Of 1778 MSD cases enrolled from 2008 to 2012, 135 (7.6%) children tested positive for tEPEC. In a case-to-case comparison among MSD cases, tEPEC was independently associated with presentation at enrolment with a loss of skin turgor (adjusted odds ratio (aOR) 2.08, 95% confidence interval (CI) 1.37-3.17), and convulsions (aOR 2.83, 95% CI 1.12-7.14). At follow-up, infants with tEPEC compared to those without were associated with being underweight (OR 2.2, 95% CI 1.3-3.6) and wasted (OR 2.5, 95% CI 1.3-4.6). Among MSD cases, tEPEC was associated with mortality (aOR 2.85, 95% CI 1.47-5.55). This study suggests that tEPEC contributes to morbidity and mortality in children. Interventions aimed at defining and reducing the burden of tEPEC and its sequelae should be urgently investigated, prioritised and implemented.

Diarrhoeal disease and subsequent risk of death in infants and children residing in low-income and middle-income countries: analysis of the GEMS case-control study and 12-month GEMS-1A follow-on study

SummaryBackgroundThe Global Enteric Multicenter Study (GEMS) was a 3-year case-control study that measured the burden, aetiology, and consequences of moderate-to-severe diarrhoea (MSD) in children aged 0–59 months. GEMS-1A, a 12-month follow-on study, comprised two parallel case-control studies, one assessing MSD and the other less-severe diarrhoea (LSD). In this report, we analyse the risk of death with each diarrhoea type and the specific pathogens associated with fatal outcomes.MethodsGEMS was a prospective, age-stratified, matched case-control study done at seven sites in Africa and Asia. Children aged 0–59 months with MSD seeking care at sentinel health centres were recruited along with one to three randomly selected matched community control children without diarrhoea. In the 12-month GEMS-1A follow-on study, children with LSD and matched controls, in addition to children with MSD and matched controls, were recruited at six of the seven sites; only cases of MSD and controls were enrolled at the seventh site. We compared risk of death during the period between enrolment and one follow-up household visit done about 60 days later (range 50–90 days) in children with MSD and LSD and in their respective controls. Approximately 50 pathogens were detected using, as appropriate, classic bacteriology, immunoassays, gel-based PCR and reverse transcriptase PCR, and quantitative real-time PCR (qPCR). Specimens from a subset of GEMS cases and controls were also tested by a TaqMan Array Card that compartmentalised probe-based qPCR for 32 enteropathogens.Findings223 (2·0%) of 11 108 children with MSD and 43 (0·3%) of 16 369 matched controls died between study enrolment and the follow-up visit at about 60 days (hazard ratio [HR] 8·16, 95% CI 5·69–11·68, p<0·0001). 12 (0·4%) of 2962 children with LSD and seven (0·2%) of 4074 matched controls died during the follow-up period (HR 2·78, 95% CI 0·95–8·11, p=0·061). Risk of death was lower in children with dysenteric MSD than in children with non-dysenteric MSD (HR 0·20, 95% CI 0·05–0·87, p=0·032), and lower in children with LSD than in those with non-dysenteric MSD (HR 0·29, 0·14–0·59, p=0·0006). In children younger than 24 months with MSD, infection with typical enteropathogenic Escherichia coli, enterotoxigenic E coli encoding heat-stable toxin, enteroaggregative E coli, Shigella spp (non-dysentery cases), Aeromonas spp, Cryptosporidium spp, and Entamoeba histolytica increased risk of death. Of 61 deaths in children aged 12–59 months with non-dysenteric MSD, 31 occurred among 942 children qPCR-positive for Shigella spp and 30 deaths occurred in 1384 qPCR-negative children (HR 2·2, 95% CI 1·2–3·9, p=0·0090), showing that Shigella was strongly associated with increased risk of death.InterpretationRisk of death is increased following MSD and, to a lesser extent, LSD. Considering there are approximately three times more cases of LSD than MSD in the population, more deaths are expected among children with LSD than in those with MSD. Because the major attributable LSD-associated and MSD-associated pathogens are the same, implementing vaccines and rapid diagnosis and treatment interventions against these major pathogens are rational investments.FundingBill & Melinda Gates Foundation.

Determinants of linear growth faltering among children with moderate-to-severe diarrhea in the Global Enteric Multicenter Study

BackgroundModerate-to-severe diarrhea (MSD) in the first 2 years of life can impair linear growth. We sought to determine risk factors for linear growth faltering and to build a clinical prediction tool to identify children most likely to experience growth faltering following an episode of MSD.MethodsUsing data from the Global Enteric Multicenter Study of children 0–23 months old presenting with MSD in Africa and Asia, we performed log-binomial regression to determine clinical and sociodemographic factors associated with severe linear growth faltering (loss of ≥ 0.5 length-for-age z-score [LAZ]). Linear regression was used to estimate associations with ΔLAZ. A clinical prediction tool was developed using backward elimination of potential variables, and Akaike Information Criterion to select the best fit model.ResultsOf the 5902 included children, mean age was 10 months and 43.2% were female. Over the 50–90-day follow-up period, 24.2% of children had severe linear growth faltering and the mean ΔLAZ over follow-up was − 0.17 (standard deviation [SD] 0.54). After adjustment for age, baseline LAZ, and site, several factors were associated with decline in LAZ: young age, acute malnutrition, hospitalization at presentation, non-dysenteric diarrhea, unimproved sanitation, lower wealth, fever, co-morbidity, or an IMCI danger sign. Compared to children 12–23 months old, those 0–6 months were more likely to experience severe linear growth faltering (adjusted prevalence ratio [aPR] 1.97 [95% CI 1.70, 2.28]), as were children 6–12 months of age (aPR 1.72 [95% CI 1.51, 1.95]). A prediction model that included age, wasting, stunting, presentation with fever, and presentation with an IMCI danger sign had an area under the ROC (AUC) of 0.67 (95% CI 0.64, 0.69). Risk scores ranged from 0 to 37, and a cut-off of 21 maximized sensitivity (60.7%) and specificity (63.5%).ConclusionYounger age, acute malnutrition, MSD severity, and sociodemographic factors were associated with short-term linear growth deterioration following MSD. Data routinely obtained at MSD may be useful to predict children at risk for growth deterioration who would benefit from interventions.

1660. Protective Effect of Living with Animals on Diarrheal Illness Among Children Younger Than Five in Sub-Saharan Africa and South Asia

BackgroundDiarrheal disease is one of the top three causes of death in children <5 years old, with the majority occurring in sub-Saharan Africa and South Asia. Animals are known reservoirs of diarrheal pathogens. While previous studies have investigated companion animals and livestock as contributors to human diarrheal disease, few have investigated this association in sub-Saharan Africa and/or South Asia among children younger than 5 years old. The aim of this study was to determine the relationship between animals living in or near the home and diarrheal disease in this population.MethodsWe conducted a secondary analysis of the Global Enteric Multicenter Study (GEMS), a case–control study that described the epidemiology of and evaluated the risk factors for diarrheal illness in children <5 years old living in sub-Saharan Africa and South Asia. Children with moderate-to-severe diarrhea (MSD) were matched to community controls without diarrhea. Associations between the predictor of animals present in a child’s living environment and the outcomes of diarrhea and diarrheal pathogens were assessed using multivariable conditional logistic regression with alpha = 0.05. Known risk factors for MSD were assessed for confounding.ResultsFrom December 1, 2007 to March 3, 2011, there were 9,439 cases with MSD and 13,128 controls enrolled in GEMS. 87% of children had at least 1 animal present at their home. When controlling for exclusive breastfeeding, access to an improved water source, access to a private improved sanitation facility, and the number of children <5 living in the home, children were less likely to have MSD if there was at least one animal present at their home (aOR 0.66, CI95 0.59 – 0.74). Children living with an animal were also 15% less likely to be colonized or infected with a viral diarrheal pathogen (aOR 0.85, CI95 0.72–0.99), when controlling for exclusive breastfeeding. There were no significant differences in the presence of bacterial or protozoal pathogens in the stool of children with and without animals present at their home.ConclusionIn contrast to prior research, having an animal present at the home does not appear to increase the risk of childhood diarrhea. Furthermore, the presence of animals may have a protective effect against viral diarrheal disease in young children. Additional research is needed to gain greater understanding of this relationship.Disclosures All authors: No reported disclosures.

The seasonality of diarrheal pathogens: A retrospective study of seven sites over three years.

BackgroundPediatric diarrhea can be caused by a wide variety of pathogens, from bacteria to viruses to protozoa. Pathogen prevalence is often described as seasonal, peaking annually and associated with specific weather conditions. Although many studies have described the seasonality of diarrheal disease, these studies have occurred predominantly in temperate regions. In tropical and resource-constrained settings, where nearly all diarrhea-associated mortality occurs, the seasonality of many diarrheal pathogens has not been well characterized. As a retrospective study, we analyze the seasonal prevalence of diarrheal pathogens among children with moderate-to-severe diarrhea (MSD) over three years from the seven sites of the Global Enteric Multicenter Study (GEMS), a case–control study. Using data from this expansive study on diarrheal disease, we characterize the seasonality of different pathogens, their association with site-specific weather patterns, and consistency across study sites.Methodology/Principal findingsUsing traditional methodologies from signal processing, we found that certain pathogens peaked at the same time every year, but not at all sites. We also found associations between pathogen prevalence and weather or “seasons,” which are defined by applying modern machine-learning methodologies to site-specific weather data. In general, rotavirus was most prevalent during the drier “winter” months and out of phase with bacterial pathogens, which peaked during hotter and rainier times of year corresponding to “monsoon,” “rainy,” or “summer” seasons.Conclusions/SignificanceIdentifying the seasonally-dependent prevalence for diarrheal pathogens helps characterize the local epidemiology and inform the clinical diagnosis of symptomatic children. Our multi-site, multi-continent study indicates a complex epidemiology of pathogens that does not reveal an easy generalization that is consistent across all sites. Instead, our study indicates the necessity of local data to characterizing the epidemiology of diarrheal disease. Recognition of the local associations between weather conditions and pathogen prevalence suggests transmission pathways and could inform control strategies in these settings.

Viral Pathogen-Specific Clinical and Demographic Characteristics of Children with Moderate-to-Severe Diarrhea in Rural Bangladesh.

Diarrheal disease is a leading cause of childhood morbidity and mortality worldwide, but particularly in low-income countries in sub-Saharan Africa and South Asia. The Global Enteric Multicenter Study (GEMS) examined the infectious etiologies as well as associated demographics, socioeconomic markers, health-care-seeking behaviors, and handwashing practices of the households of children with diarrhea and their age- and gender-matched controls in seven countries over a 3-year period (December 2007-December 2010). Stool studies to determine diarrheal etiologies and anthropometry were performed at baseline and at 60-day follow-up visits, along with surveys to record demographics and living conditions of the children. We performed secondary analyses of the GEMS data derived from the Bangladesh portion of the study in children with diarrhea associated with viral enteropathogens and explored pathogen-specific features of disease burden. Rotavirus and norovirus were the most prevalent pathogens (39.3% and 35%, respectively). Disease due to rotavirus and adenovirus was more common in infants than in older children (P < 0.001 and P = 0.001, respectively). Height for age decreased from baseline to follow-up in children with diarrhea associated with rotavirus, norovirus, and adenovirus (P < 0.001). Based on these analyses, preventive measures targeted at rotavirus, norovirus, and adenovirus will be expected to have meaningful clinical impact. Cost of treatment was highest for rotavirus as well, making it an obvious target for intervention. Association of specific viruses with stunting is particularly notable, as stunting is an attributable risk factor for poor cognitive development and future productivity and economic potential.

Cryptosporidium infection in rural Gambian children: Epidemiology and risk factors.

BackgroundCryptosporidium is a major pathogen associated with diarrheal disease in young children. We studied Cryptosporidium diarrhea in children enrolled in the Global Enteric Multicenter Study (GEMS) in rural Gambia.MethodsWe recruited children <5 years of age with moderate-to-severe diarrhea (MSD) for 3 years (2008–2010), and children with either MSD or less severe diarrhea (LSD) for one year (November 2011-November 2012) at sentinel health centers. One or more randomly selected controls were matched to each case. Stool samples were tested to identify Cryptosporidium by immunoassay. A subset of randomly selected case-controls pairs were tested for Cryptosporidium species. We investigated the epidemiology of, and evaluated possible risk factors for, Cryptosporidium-positive diarrhea.ResultsWe enrolled 1938 cases (1381 MSD, 557 LSD) and 2969 matched controls; 231/1929 (12.0%) of diarrhea cases and 141/2962 (4.8%) of controls were positive for Cryptosporidium. Most Cryptosporidium diarrhea cases (85.7%, 198/231) were aged 6–23 months, and most (81.4%, 188/231) occurred during the rainy season. Cryptosporidium hominis (C. hominis) was the predominant (82.6%) species. We found associations between increased risk of Cryptosporidium-positive MSD or LSD, or both, with consumption of stored drinking water and certain animals living in the compound—cow, cat (MSD only) and rodents (LSD only). Larger households, fowl living in the compound, and the presence of Giardia infection were associated with decreased risk of Cryptosporidium MSD and LSD.ConclusionCryptosporidium-positive diarrhea is prevalent in this setting, especially at 6–23 months of age. The preponderance of Cryptosporidium infection in the rainy season and increased risk of Cryptosporidium-positive diarrhea with consumption of stored drinking water suggest water-borne transmission. Further investigation is needed to clarify the role of animals and contamination of stored drinking water in Cryptosporidium transmission.

Relation of childhood diarrheal morbidity with the type of tube well used and associated factors of Shigella sonnei diarrhea in rural Bangladesh site of the Global Enteric Multicenter Study

BackgroundDiarrheal disease still remains a major public health threat and is often associated with fatal outcome especially in children with shigellosis mostly in developing countries. This study aimed to determine the presence of any associations between drinking shallow tube well (STW) water and childhood shigellosis. A total of 1394 children aged 0–59 months who presented with moderate-to-severe diarrhea (MSD) in Kumudini Women’s Medical College and Hospital, Bangladesh, from December 2007 to March 2011 were enrolled into the study.ResultsAmong the study children, STW users often represented poor families (44% vs. 37%, p = 0.010); less often had household electricity (60% vs. 68%, p = 0.001) and cemented floor material (12% vs. 21%, p < 0.001); washed hand before eating (79% vs. 84%, p = 0.020); and had Shigella sonnei infections (7.8% vs. 13.1, p = 0.002) compared to deep tube well (DTW) water families (in bivariate analysis). After adjusting for covariates, a significant negative association was observed between childhood MSD episodes due to Shigella sonnei infections and the use of STW water (aOR 0.53, 95% CI 0.36, 0.79).ConclusionsAn emergence of less severe Shigella sonnei has replaced relatively more severe Shigella flexneri among the MSD children from DTW-user families. However, more monitoring in terms of disease surveillance for changes in the distribution of Shigella serogroups and serotypes and its upsurges and antimicrobial susceptibility is essential.

The incidence, aetiology, and adverse clinical consequences of less severe diarrhoeal episodes among infants and children residing in low-income and middle-income countries: a 12-month case-control study as a follow-on to the Global Enteric Multicenter Study (GEMS)

SummaryBackgroundDiarrheal diseases remain a leading cause of illness and death among children younger than 5 years in low-income and middle-income countries. The Global Enteric Multicenter Study (GEMS) has described the incidence, aetiology, and sequelae of medically attended moderate-to-severe diarrhoea (MSD) among children aged 0–59 months residing in censused populations in sub-Saharan Africa and south Asia, where most child deaths occur. To further characterise this disease burden and guide interventions, we extended this study to include children with episodes of less-severe diarrhoea (LSD) seeking care at health centres serving six GEMS sites.MethodsWe report a 1-year, multisite, age-stratified, matched case-control study following on to the GEMS study. Six sites (Bamako, Mali; Manhiça, Mozambique; Basse, The Gambia; Mirzapur, Bangladesh; Kolkata, India; and Bin Qasim Town, Karachi, Pakistan) participated in this study. Children aged 0–59 months at each site who sought care at a sentinel hospital or health centre during a 12-month period were screened for diarrhoea. New (onset after ≥7 diarrhoea-free days) and acute (onset within the previous 7 days) episodes of diarrhoea in children who had sunken eyes, whose skin lost turgor, who received intravenous hydration, who had dysentery, or who were hospitalised were eligible for inclusion as MSD. The remaining new and acute diarrhoea episodes among children who sought care at the same health centres were considered LSD. We aimed to enrol the first eight or nine eligible children with MSD and LSD at each site during each fortnight in three age strata: infants (aged 0–11 months), toddlers (aged 12–23 months), and young children (aged 24–59 months). For each included case of MSD or LSD, we enrolled one to three community control children without diarrhoea during the previous 7 days. From patients and controls we collected clinical and epidemiological data, anthropometric measurements, and faecal samples to identify enteropathogens at enrolment, and we performed a follow-up home visit about 60 days later to ascertain vital status, clinical outcome, and interval growth. Primary outcomes were to characterise, for MSD and LSD, the pathogen-specific attributable risk and population-based incidence values, and to assess the frequency of adverse clinical consequences associated with these two diarrhoeal syndromes.FindingsFrom Oct 31, 2011, to Nov 14, 2012, we recruited 2368 children with MSD, 3174 with LSD, and one to three randomly selected community control children without diarrhoea matched to cases with MSD (n=3597) or LSD (n=4236). Weighted adjusted population attributable fractions showed that most attributable cases of MSD and LSD were due to rotavirus, Cryptosporidium spp, enterotoxigenic Escherichia coli encoding heat-stable toxin (with or without genes encoding heat-labile enterotoxin), and Shigella spp. The attributable incidence per 100 child-years for LSD versus MSD, by age stratum, for rotavirus was 22·3 versus 5·5 (0–11 months), 9·8 versus 2·9 (12–23 months), and 0·5 versus 0·2 (24–59 months); for Cryptosporidium spp was 3·6 versus 2·3 (0–11 months), 4·3 versus 0·6 (12–23 months), and 0·3 versus 0·1 (24–59 months); for enterotoxigenic E coli encoding heat-stable toxin was 4·2 versus 0·1 (0–11 months), 5·2 versus 0·0 (12–23 months), and 1·1 versus 0·2 (24–59 months); and for Shigella spp was 1·0 versus 1·3 (0–11 months), 3·1 versus 2·4 (12–23 months), and 0·8 versus 0·7 (24–59 months). Participants with both MSD and LSD had significantly more linear growth faltering than controls at follow-up.InterpretationInclusion of participants with LSD markedly expands the population of children who experience adverse clinical and nutritional outcomes from acute diarrhoeal diseases. Since MSD and LSD have similar aetiologies, interventions targeting rotavirus, Shigella spp, enterotoxigenic E coli producing heat-stable toxin, and Cryptosporidium spp might substantially reduce the diarrhoeal disease burden and its associated nutritional faltering.FundingBill & Melinda Gates Foundation.

Risk factors for death among children 0\u201359\u2009months of age with moderate-to-severe diarrhea in Manhi\xe7a district, southern Mozambique

BackgroundDespite major improvements in child survival rates, the number of deaths due to diarrhea remains unacceptably high. We aimed to describe diarrhea-associated mortality and evaluate risk factors for death among Mozambican children with moderate-to-severe diarrhea (MSD).MethodsBetween December 2007 and November 2012, children under-five with MSD were enrolled in Manhiça district, as part of the Global Enteric Multicenter study (GEMS). Clinical, epidemiological, and socio-demographic characteristics were collected. Anthropometric measurements were performed and stool samples collected upon recruitment. A follow-up visit ~ 60 days post-enrolment was conducted and verbal autopsies performed in all death cases.ResultsOf the 916 MSD-cases analyzed; 90% (821/916) completed 60 days follow-up and 69 patients died. The case fatality rate at follow-up was 8% (69/821), and the mortality rate 10.2 (95%CI: 7.75–13.59) deaths per 1000 persons-week at risk. Nearly half of the deaths 48% (33/69) among study participants clustered within 2 weeks of the onset of diarrhea.Typical enteropathogenic Escherichia coli (typical EPEC) and Cryptosporidium were the two pathogens associated to an increased risk of death in the univariate analysis with (HR = 4.16, p = 0.0461) and (H = 2.84, p = 0.0001) respectively. Conversely, Rotavirus infection was associated to a decreased risk of death (HR = 0.52, p = 0.0198).According to the multivariate analysis, risk factors for death included co-morbidities such as malnutrition (HR = 4.13, p < 0.0001), pneumonia/lower respiratory infection (HR = 3.51, p < 0.0001) or invasive bacterial disease (IBD) (HR = 6.80, p = 0.0009), presenting on arrival with lethargy or overt unconsciousness (HR = 1.73, p = 0.0302) or wrinkled skin (HR = 1.71, p = 0.0393), and cryptosporidium infection (HR = 2.14, p = 0.0038).When restricting the analysis to those with available HIV results (n = 191, 22% of the total study sample), HIV was shown to be a significant risk factor for death (HR = 5.05, p = 0.0009).Verbal autopsies were conducted in 100% of study deaths, and highlighted diarrhea as the main underlying cause of death 39%, (27/69); followed by HIV/AIDS related deaths 29.0% (20/69) and sepsis 11.6% (8/69).ConclusionPreventive strategies targeting Cryptosporidium, malnutrition and early identification and treatment of associated co-morbidities could contribute to the prevention of the majority of diarrhea associated deaths in Mozambican children.

Household Costs of Diarrhea by Etiology in 7 Countries, The Global Enterics Mulitcenter Study (GEMS).

BackgroundAlthough there are many overlapping features, pediatric diarrheal diseases can vary in severity, duration, clinical manifestations, and sequelae according to the causal pathogen, which in turn can impact the economic burden on patients and their families. We aimed to evaluate the household costs of diarrheal disease by pathogen in 7 countries.MethodsWe analyzed data from the Global Enteric Multicenter Study (GEMS), a prospective, age-stratified, matched case–control study of moderate to severe diarrheal disease among children aged 0–59 months in 7 low-income countries; 4 in Africa (Kenya, Mali, Mozambique, The Gambia) and 3 in Asia (Bangladesh, India, Pakistan). Demographic, epidemiological, economic, and clinical data were collected, and a stool sample was obtained for microbiological analysis at enrollment. We used a multivariate generalized linear model to assess the effect of rotavirus, Cryptosporidium, heat-stable toxin (ST)–producing enterotoxigenic Escherichia coli (ETEC [ST only or LT plus ST]), Shigella, Campylobacter jejuni, norovirus GII, Vibrio cholerae O1, age, gender, in/outpatient, and country on total costs to the patient/family.ResultsHousehold out-of-pocket costs were higher in Mali than any other country. Within countries, household cost differences between pathogens were minimal and not statistically significantly different.ConclusionsWe found no significant differences in household costs by pathogen. Despite data limitations, understanding pathogen-specific household costs (or lack thereof) is useful, as decision-makers could consider broader illness cost information and its relevance to a particular pathogen’s economic burden and contribution to poverty when deciding which pathogens to target for interventions.

Colonization factors among enterotoxigenic Escherichia coli isolates from children with moderate-to-severe diarrhea and from matched controls in the Global Enteric Multicenter Study (GEMS)

BackgroundEnterotoxigenic Escherichia coli (ETEC) encoding heat-stable enterotoxin (ST) alone or with heat-labile enterotoxin (LT) cause moderate-to-severe diarrhea (MSD) in developing country children. The Global Enteric Multicenter Study (GEMS) identified ETEC encoding ST among the top four enteropathogens. Since the GEMS objective was to provide evidence to guide development and implementation of enteric vaccines and other interventions to diminish diarrheal disease morbidity and mortality, we examined colonization factor (CF) prevalence among ETEC isolates from children age <5 years with MSD and from matched controls in four African and three Asian sites. We also assessed strength of association of specific CFs with MSD.Methodology/Principal findingsMSD cases enrolled at healthcare facilities over three years and matched controls were tested in a standardized manner for many enteropathogens. To identify ETEC, three E. coli colonies per child were tested by polymerase chain reaction (PCR) to detect genes encoding LT, ST; confirmed ETEC were examined by PCR for major CFs (Colonization Factor Antigen I [CFA/I] or Coli Surface [CS] antigens CS1-CS6) and minor CFs (CS7, CS12, CS13, CS14, CS17, CS18, CS19, CS20, CS21, CS30). ETEC from 806 cases had a single toxin/CF profile in three tested strains per child. Major CFs, components of multiple ETEC vaccine candidates, were detected in 66.0% of LT/ST and ST-only cases and were associated with MSD versus matched controls by conditional logistic regression (p≤0.006); major CFs detected in only 25.0% of LT-only cases weren’t associated with MSD. ETEC encoding exclusively CS14, identified among 19.9% of 291 ST-only and 1.5% of 259 LT/ST strains, were associated with MSD (p = 0.0011). No other minor CF exhibited prevalence ≥5% and significant association with MSD.Conclusions/SignificanceMajor CF-based efficacious ETEC vaccines could potentially prevent up to 66% of pediatric MSD cases due to ST-encoding ETEC in developing countries; adding CS14 extends coverage to ~77%.

Diarrhoea, enteric pathogen detection and nutritional indicators among controls in the Global Enteric Multicenter Study, Kenya site: an opportunity to understand reference populations in case-control studies of diarrhoea.

Given the challenges in accurately identifying unexposed controls in case-control studies of diarrhoea, we examined diarrhoea incidence, subclinical enteric infections and growth stunting within a reference population in the Global Enteric Multicenter Study, Kenya site. Within 'control' children (0-59 months old without diarrhoea in the 7 days before enrolment, n = 2384), we examined surveys at enrolment and 60-day follow-up, stool at enrolment and a 14-day post-enrolment memory aid for diarrhoea incidence. At enrolment, 19% of controls had ⩾1 enteric pathogen associated with moderate-to-severe diarrhoea ('MSD pathogens') in stool; following enrolment, many reported diarrhoea (27% in 7 days, 39% in 14 days). Controls with and without reported diarrhoea had similar carriage of MSD pathogens at enrolment; however, controls reporting diarrhoea were more likely to report visiting a health facility for diarrhoea (27% vs. 7%) or fever (23% vs. 16%) at follow-up than controls without diarrhoea. Odds of stunting differed by both MSD and 'any' (including non-MSD pathogens) enteric pathogen carriage, but not diarrhoea, suggesting control classification may warrant modification when assessing long-term outcomes. High diarrhoea incidence following enrolment and prevalent carriage of enteric pathogens have implications for sequelae associated with subclinical enteric infections and for design and interpretation of case-control studies examining diarrhoea.

Water, Sanitation, and Hygiene Characteristics among HIV-Positive Households Participating in the Global Enteric Multicenter Study in Rural Western Kenya, 2008-2012.

Diarrheal illness, a common occurrence among people living with human immunodeficiency virus (PLHIV), is largely preventable through access to safe drinking water quality, sanitation, and hygiene (WASH) facilities. We examined WASH characteristics among households with and without HIV-positive residents enrolled in the Global Enteric Multicenter Study (GEMS) in rural Western Kenya. Using univariable logistic regression, we examined differences between HIV-positive and HIV-negative households in regard to WASH practices. Among HIV-positive households, we explored the relationship between the length of time knowing their HIV status and GEMS enrollment. No statistically significant differences were apparent in the WASH characteristics among HIV-positive and HIV-negative households. However, we found differences in the WASH characteristics among HIV-positive households who were aware of their HIV status ≥ 30 days before enrollment compared with HIV-positive households who found out their status < 30 days before enrollment or thereafter. Significantly more households aware of their HIV-positive status before enrollment reported treating their drinking water (odds ratio [OR] confidence interval [CI]: 2.34 [1.12, 4.86]) and using effective water treatment methods (OR [CI]: 9.6 [3.09, 29.86]), and had better drinking water storage practices. This suggests that within this region of Kenya, HIV programs are effective in promoting the importance of practicing positive WASH-related behaviors among PLHIV.

Clinical, environmental, and behavioral characteristics associated with Cryptosporidium infection among children with moderate-to-severe diarrhea in rural western Kenya, 2008-2012: The Global Enteric Multicenter Study (GEMS).

BackgroundCryptosporidium is a leading cause of moderate-to-severe diarrhea (MSD) in young children in Africa. We examined factors associated with Cryptosporidium infection in MSD cases enrolled at the rural western Kenya Global Enteric Multicenter Study (GEMS) site from 2008-2012.Methodology/Principal findingsAt health facility enrollment, stool samples were tested for enteric pathogens and data on clinical, environmental, and behavioral characteristics collected. Each child’s health status was recorded at 60-day follow-up. Data were analyzed using logistic regression. Of the 1,778 children with MSD enrolled as cases in the GEMS-Kenya case-control study, 11% had Cryptosporidium detected in stool by enzyme immunoassay; in a genotyped subset, 81% were C. hominis. Among MSD cases, being an infant, having mucus in stool, and having prolonged/persistent duration diarrhea were associated with being Cryptosporidium-positive. Both boiling drinking water and using rainwater as the main drinking water source were protective factors for being Cryptosporidium-positive. At follow-up, Cryptosporidium-positive cases had increased odds of being stunted (adjusted odds ratio [aOR] = 1.65, 95% CI: 1.06–2.57), underweight (aOR = 2.08, 95% CI: 1.34–3.22), or wasted (aOR = 2.04, 95% CI: 1.21–3.43), and had significantly larger negative changes in height- and weight-for-age z-scores from enrollment.Conclusions/SignificanceCryptosporidium contributes significantly to diarrheal illness in young children in western Kenya. Advances in point of care detection, prevention/control approaches, effective water treatment technologies, and clinical management options for children with cryptosporidiosis are needed.

The role of HIV infection in the etiology and epidemiology of diarrheal disease among children aged 0–59 months in Manhiça District, Rural Mozambique

BackgroundDiarrhea is an important health problem among HIV-infected patients. This study evaluated the role of HIV in the epidemiology, etiology, and severity of diarrheal disease among children. MethodsThe Global Enteric Multicenter Study enrolled children with moderate-to-severe diarrhea (MSD) and less-severe diarrhea (LSD) between December 2007 and November 2012. One to three controls for MSD cases and one per LSD case were enrolled and matched by age, sex, and neighborhood. All children were tested for HIV. Clinical data, anthropometric data, and stool samples were collected. Follow-up was performed at 60 days. ResultsTwo hundred and fourteen MSD cases and 418 controls, together with 349 LSD cases and 214 controls were tested. HIV prevalence was 25% among MSD cases (4% for matched controls) and 6% among LSD cases (6% among matched controls). HIV-infected children were more likely to have MSD (odds ratio 5.6, p<0.0001).Mortality rates were higher among HIV-infected children than among the uninfected (34 vs. 5 per 1000 child-weeks at risk; p=0.0039). Cryptosporidium, Giardia, and enteroaggregative Escherichia coli (aatA only) were more prevalent among HIV-infected MSD cases than among uninfected ones. ConclusionHIV is an important risk factor for MSD. The high mortality rate implies that children with MSD should be screened for HIV and managed accordingly.

Development of novel in vitro and in vivo models to evaluate antibiotic efficacy against shigellosis

Shigellosis is caused by oral ingestion of the gram‐negative bacteria Shigella. Symptoms of the disease include severe diarrhea and dysentery, and the impact of the disease disproportionately affects children and those in low‐income countries such as sub‐Saharan Africa, Asia, and Latin America. According to a reanalysis of the Global Enteric Multicenter Study (GEMS), Shigella has the highest attributable incidence of pathogen specific moderate to severe diarrhea in children between 12–59 months of age. Recent studies have estimated approximately 90 million shigellosis cases annually, and the Global Burden of Disease 2015 analysis suggests at least 164,000 deaths per year are due to Shigella. Interspecies‐variation with lack of cross‐protection may challenge the development of a broadly‐protective vaccine and no human vaccine candidates are currently approved for treatment. Therapeutic options for shigellosis are limited and globally emerging drug resistance to sulfonamides, tetracyclines, ampicillin, and TMP‐SMX has been reported. With resistance to many “first‐line” antibiotics, ciprofloxacin, azithromycin, and ceftriaxone have been recommended for treatment of shigellosis. However, rapidly evolving resistance has been reported for these antibiotics as well. While there is a clear need for novel therapeutics to treat this disease, current drug development efforts are hindered by a lack of fundamental in vitro and in vivo tools to assess the efficacy of pre‐clinical candidates. We have focused our efforts on establishing in vitro co‐culture systems and in vivo mouse models to evaluate small molecule therapeutics. Our aim is to use these tools to identify PK/PD relationships for established and novel therapeutics to treat Shigella infection. The gastrointestinal localization of the parasite generates a unique challenge for establishing a pharmacokinetic‐pharmacodynamic (PK/PD) relationship for an anti‐Shigella drug candidate. We have previously reported on our use of physiology based pharmacokinetic (PBPK) modeling to identify an association between gastrointestinal drug concentrations and in vivo efficacy for anti‐Cryptosporidium drugs and we plan to use a similar technique for the antibiotics used to treat Shigella infection. The presented work will be valuable for the entire research community currently engaged in the development of therapeutics for enteric diseases.Support or Funding InformationThis work was supported by the Tres Cantos Open Lab Foundation Award: TC246This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Enteric Infections in Young Children are Associated with Environmental Enteropathy and Impaired Growth.

To investigate the relationship between faecal contamination in child play spaces, enteric infections, environmental enteropathy (EE) and impaired growth among young children. A prospective cohort study was conducted of 203 children 6-30months of age in rural Bangladesh. Stool samples were analysed by quantitative PCR for Shigella, Enterotoxigenic Escherichia coli (ETEC), Campylobacter jejuni, Giardia intestinalis and Cryptosporidium spp. Four faecal markers of intestinal inflammation were also measured: alpha-1-antitrypsin, myeloperoxidase, neopterin and calprotectin. Child growth was measured at baseline and 9months after enrolment. E.coli was measured in soil in child play spaces. Forty-seven percent of study children had three or more enteric pathogens in their stool. Thirty five percent (71/203) of children had Shigella, 30% (61/203) had ETEC, 73% (148/203) had C.jejuni, 79% (160/203) had Giardia intestinalis and none had Cryptosporidium. Children with ETEC had significantly higher calprotectin concentrations (Coefficient: 1.35, 95% Confidence Interval [CI]: 1.005, 1.82). Children with Shigella had a significantly higher odds of being stunted at our 9-month follow-up (OR: 2.01, 95% CI: 1.02, 3.93). Children with Giardia intestinalis had significantly higher E.coli counts in the soil collected from their play spaces (OR: 1.23, 95% CI: 1.02, 1.48). Enteric infections were significantly associated with EE and impaired growth in rural Bangladesh. These findings provide further evidence to support the hypothesis that contaminated soil in child play spaces can lead to enteric infections, many of which are likely subclinical, resulting in EE and impaired growth in young children.

The Global Burden of Shigella and Enterotoxigenic E. coli: Results from the Global Burden of Disease Study 2016

BackgroundDiarrhea is the seventh leading cause of death globally, responsible for more than 1,600,000 deaths in 2016 and nearly 90% of these deaths occurred in sub-Saharan Africa and South Asia. The Global Burden of Disease Study (GBD) is an annual effort to produce and refine estimates of diarrheal disease burden attributable to Shigella spp., enterotoxigenic Escherichia coli (ETEC), and other enteric pathogens.MethodsWe used a counter-factual approach to estimate deaths, incidence, years of life lost (YLLs), years living with disability (YLDs), and total disability adjusted life years (DALYs) attributable to diarrhea and its etiologies, including Shigella and ETEC. To estimate the burden of diarrhea etiologies, we conducted a systematic review of the proportion of diarrheal cases positive for each pathogen and modeled these data using a Bayesian meta-regression tool called DisMod-MR. This tool generates estimates of the pathogen distribution for national and some subnational geographies, all age groups, and for both sexes from 1990 to 2016. We used these estimates, in conjunction with odds ratios for diarrhea given pathogen detection from the Global Enteric Multicenter Study, to calculate the population attributable fraction for each pathogen.ResultsIn 2016, Shigella was responsible for 75,000 deaths among children under-5 and 270,000 deaths among all ages and ETEC was responsible for 22,000 deaths among children under-5 and 60,000 deaths among all ages. Shigella and ETEC ranked second and fourth with regard to pathogen contributions to global diarrheal deaths.ConclusionThe global burden of disease attributable to Shigella and ETEC is substantial. GBD 2016 estimates on the age- and location-specific impact of Shigella and ETEC enable evidence-based decision making regarding interventions to reduce the burden of these pathogens. Our findings call for accelerated efforts for the development of vaccines against ETEC and Shigella.Disclosures All authors: No reported disclosures.