Global Enteric Multicenter Study Research Articles

Estimated global and regional causes of deaths from diarrhoea in children younger than 5 years during 2000–21: a systematic review and Bayesian multinomial analysis

Information on the causes of deaths from diarrhoea in children younger than 5 years is needed to design improved preventive and therapeutic approaches. We aimed to conduct a systematic analysis of studies to report estimates of the causes of deaths from diarrhoea in children younger than 5 years at global and regional levels during 2000-21. For this systematic review and Bayesian multinomial analysis, we included 12 pathogens with the highest attributable incidence in the Global Enteric Multicenter Study. We searched PubMed, Scopus, Embase, Web of Science, Global Health Index Medicus, Global Health OVID, IndMed, Health Information Platform for the Americas (PLISA), Africa-Wide Information, and Cochrane Collaboration for articles published between Jan 1, 2000, and Dec 31, 2020, using the search terms "child", "hospital", "diarrhea", "diarrhoea", "dysentery", "rotavirus", "Escherichia coli", "salmonella", "shigella", "campylobacter", "Vibrio cholerae", "cryptosporidium", "norovirus", "astrovirus", "sapovirus", and "adenovirus". To be included, studies had to have a patient population of children younger than 5 years who were hospitalised for diarrhoea (at least 90% of study participants), at least a 12-month duration, reported prevalence in diarrhoeal stools of at least two of the 12 pathogens, all patients with diarrhoea being included at the study site or a systematic sample, at least 100 patients with diarrhoea, laboratory tests done on rectal swabs or stool samples, and standard laboratory methods (ie, quantitative PCR [qPCR] or non-qPCR). Studies published in any language were included. Studies were excluded if they were limited to nosocomial, chronic, antibiotic-associated, or outbreak diarrhoea or to a specific population (eg, only children with HIV or AIDS). Each article was independently reviewed by two researchers; a third arbitrated in case of disagreement. If both reviewers identified an exclusion criterion, the study was excluded. Data sought were summary estimates. Data on causes from published studies were adjusted when necessary to account for the poor sensitivity of non-qPCR methods and for attributable fraction based on quantification of pathogens in children who are ill or non-ill. The causes of deaths from diarrhoea were modelled on the causes of hospitalisations for diarrhoea. We separately modelled studies reporting causes of diarrhoea in children who were hospitalised in low-income and middle-income countries (LMICs) and in high-income countries (HICs). Of 74 282 papers identified in the initial database search, we included 138 studies (91 included data from LMICs and 47 included data from HICs) from 73 countries. We modelled estimates for 194 WHO member states (hereafter referred to as countries), including 42 HICs and 152 LMICs. We could attribute a cause to 1 003 448 (83·8%) of the estimated 1 197 044 global deaths from diarrhoea in children younger than 5 years in 2000 and 360 730 (81·3%) of the estimated 443 833 global deaths from diarrhoea in children younger than 5 years in 2021. The cause with the largest estimated global attribution was rotavirus; in LMICs, the proportion of deaths from diarrhoea due to rotavirus in children younger than 5 years appeared lower in 2021 (108 322 [24·4%] of 443 342, 95% uncertainty interval 21·6-29·5) than in 2000 (316 382 [26·5%] of 1 196 134, 25·7-28·5), but the 95% CIs overlapped. In 2000, the second largest estimated attribution was norovirus GII (95 817 [8·0%] of 1 196 134 in LMICs and 225 [24·7%] of 910 in HICs); in 2021, Shigella sp had the second largest estimated attribution in LMICs (36 082 [8·1%] of 443 342), but norovirus remained with the second largest estimated attribution in HICs (84 [17·1%] of 490). Our results indicate progress in the reduction of deaths from diarrhoea caused by 12 pathogens in children younger than 5 years in the past two decades. There is a need to increase efforts for prevention, including with rotavirus vaccine, and treatment to eliminate further deaths. Bill & Melinda Gates Foundation via Johns Hopkins University and the University of Virginia.

Clinical severity of enteric viruses detected using a quantitative molecular assay compared to conventional assays in the Global Enteric Multicenter Study.

Quantitative molecular assays are increasingly used for detection of enteric viruses. We compared the clinical severity using modified Vesikari score (mVS) of enteric viruses detected by conventional assays (enzyme immunoassays [EIA] for rotavirus and adenovirus 40/41 and conventional polymerase chain reaction for astrovirus, sapovirus, and norovirus) and a quantitative molecular assay (TaqMan Array Card [TAC]) among children aged 0-59 months in the Global Enteric Multicenter Study. For rotavirus and adenovirus 40/41, we compared severity between EIA-positive and TAC-positive cases assigned etiologies using different cycle threshold (CT) cutoffs. Using conventional assays, the median (interquartile range) mVS was 10 (8, 11) for rotavirus, 9 (7, 11) for adenovirus 40/41, 8 (6, 10) for astrovirus, sapovirus, and norovirus GII, and 7 (6, 9) for norovirus GI. Compared to rotavirus EIA-positive cases, the median mVS was 2 and 3 points lower for EIA-negative/TAC-positive cases with CT<32.6 and 32.6≤CT<35, respectively (p-value<.0001). Adenovirus 40/41 EIA-positive and EIA-negative/TAC-positive cases were similar, regardless of CT cutoff. Quantitative molecular assays compared to conventional assays, such as EIA, may influence severity of identified cases, especially for rotavirus. Cutoffs to assign etiology for quantitative assays should be considered in the design and interpretation of enteric virus studies.

Impact of Rotaviral Diarrhea on Child Growth in Sub-Saharan Africa and South Asia in the Global Enteric Multicenter Study.

Rotavirus is the leading cause of dehydrating diarrhea among children in developing countries. The impact of rotaviral diarrhea on nutritional status is not well understood. We aimed to determine the association between rotavirus-positive moderate-to-severe diarrhea and nutrition in children under 5 years of age. We analyzed data from the Global Enteric Multicenter Study on children 0-59 months old from South Asia and sub-Saharan Africa. The relationships between explanatory variables and outcome variables were assessed using multiple linear regression; the explanatory variable was the presence of rotavirus in the stool sample, and the outcome variables were z scores [length/height-for-age (LAZ/HAZ), weight-for-age (WAZ), and weight-for-length/height (WLZ/WHZ)] at follow-up (∼60 days). The prevalence of rotaviral diarrhea was 17.3% (905/5,219) in South Asia and 19.95% (842/4,220) in sub-Saharan Africa. Rotavirus was associated with higher LAZ/HAZ (β: 0.19; 95% CI: 0.12, 0.26; P <0.001) and WAZ (β: 0.15; 95% CI: 0.79, 0.22; P <0.001) in sub-Saharan Africa and with lower WLZ/WHZ (β coefficient: -0.08; 95% CI: -0.15, -0.009; P = 0.027) in South Asia. Our study indicates that rotaviral diarrhea is positively associated with nutritional status in sub-Saharan Africa and is negatively associated with nutritional status in South Asia. An expedited implementation policy of ongoing preventive and control strategies, including vaccination against rotavirus, is necessary to reduce the burden of rotaviral diarrhea, which may further help to reduce the potential nutritional ramifications.

The Enterics for Global Health (EFGH) Shigella Surveillance Study in Mali.

In 2002, the Centre pour le Développement des Vaccins du Mali (CVD-Mali) was established as a partnership between the Mali Ministry of Health and the University of Maryland, Baltimore. Since its creation, CVD-Mali has been dedicated to describing the epidemiology of infectious diseases, supporting the development of vaccines, and training a team of local researchers. CVD-Mali participated in the Global Enteric Multicenter Study from 2007 to 2010 and the Vaccine Impact on Diarrhea in Africa study from 2015 to 2018, where the importance of Shigella as an enteric pathogen was established. In the Enterics for Global Health (EFGH) Shigella surveillance study, CVD-Mali will conduct Shigella surveillance at 4 health centers serving the population currently participating in a demographic surveillance system and will measure the local incidence of Shigella diarrhea and related outcomes in 6- to 35-month-old children. Antibiotic sensitivity patterns and the costs related to these cases will also be measured. We anticipate reporting the number of diarrhea episodes that are positive by stool culture, the antibiotic susceptibility of these isolates, and the management and outcomes of these cases. In Mali, the EFGH study will contribute valuable information to understanding the burden of Shigella in this population. These data will inform the evaluation of vaccine candidates.

Genomic, transcriptomic, and phenotypic differences among archetype Shigella flexneri strains of serotypes 2a, 3a, and 6.

Given the genomic diversity between S. flexneri serotypes and the paucity of data to support serotype-specific phenotypic differences, we applied in silico and in vitro functional analyses of archetype strains of 2457T (Sf2a), J17B (Sf3a), and CH060 (Sf6). These archetype strains represent the three leading S. flexneri serotypes recommended for inclusion in multivalent vaccines. Characterizing the genomic and phenotypic variation among these clinically prevalent serotypes is an important step toward understanding serotype-specific host-pathogen interactions to optimize the efficacy of multivalent vaccines and therapeutics. This study underpins the importance for further large-scale serotype-targeted analyses.

Derivation and external validation of a clinical prognostic model identifying children at risk of death following presentation for diarrheal care.

Diarrhea continues to be a leading cause of death for children under-five. Amongst children treated for acute diarrhea, mortality risk remains elevated during and after acute medical management. Identification of those at highest risk would enable better targeting of interventions, but available prognostic tools lack validation. We used clinical and demographic data from the Global Enteric Multicenter Study (GEMS) to build clinical prognostic models (CPMs) to predict death (in-treatment, after discharge, or either) in children aged ≤59 months presenting with moderate-to-severe diarrhea (MSD), in Africa and Asia. We screened variables using random forests, and assessed predictive performance with random forest regression and logistic regression using repeated cross-validation. We used data from the Kilifi Health and Demographic Surveillance System (KHDSS) and Kilifi County Hospital (KCH) in Kenya to externally validate our GEMS-derived CPM. Of 8060 MSD cases, 43 (0.5%) children died in treatment and 122 (1.5% of remaining) died after discharge. MUAC at presentation, respiratory rate, age, temperature, number of days with diarrhea at presentation, number of people living in household, number of children <60 months old living in household, and how much the child had been offered to drink since diarrhea started were predictive of death both in treatment and after discharge. Using a parsimonious 2-variable prediction model, we achieved an area under the ROC curve (AUC) of 0.84 (95% CI: 0.82, 0.86) in the derivation dataset, and an AUC = 0.74 (95% CI 0.71, 0.77) in the external dataset. Our findings suggest it is possible to identify children most likely to die after presenting to care for acute diarrhea. This could represent a novel and cost-effective way to target resources for the prevention of childhood mortality.

The long view of vaccination to secure the future

“Whether this distribution of benefits will be attractive to finance ministers depends on many factors”—so state Chloe Puett and colleagues in their analysis of the long-term economic benefits of Shigella vaccination to prevent linear growth faltering (LGF) in The Lancet Global Health.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar The cost of vaccination can be a considerable deterrent in the introduction of a new vaccine, and has contributed to the low coverage rates of rotavirus vaccines and the human papillomavirus (HPV) vaccine, which, where it has been introduced, is only focused on girls and young women,2Bruni L Saura-Lázaro A Montoliu A et al.HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010–2019.Prev Med. 2021; 144106399Crossref Scopus (173) Google Scholar despite having been shown to be beneficial in men.3Stanley M HPV vaccination in boys and men.Hum Vaccin Immunother. 2014; 10: 2109-2111Crossref PubMed Scopus (28) Google Scholar The strength of the analysis by Puett and colleagues is the novel approach it takes in describing benefit–cost ratios (BCRs), calculating the enhanced future productivity of children who have received a Shigella vaccine, through the reduction of LGF.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar Assuming a retirement age of 64 years, they calculated that the income effect of the BCR in low-income countries (LICs) and lower-middle-income countries (LMICs) would be 11·60, compared with a BCR of 8·53 when upper-middle-income countries were included.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar These analyses could be extended to other vaccines, including those in the process of being introduced (eg, the HPV and rotavirus vaccines) and others in the pipeline or in early development (eg, vaccines for respiratory syncytial virus, other enteric diseases, and tuberculosis). However, Puett and colleagues’ estimates are highly conservative, as they do not include other potential cost-benefits of Shigella vaccines. Shigella is highly transmissible and requires only a small infective dose; it is increasingly becoming multidrug-resistant and can either be endemic or cause significant outbreaks.4Kotloff KL Shigella infection in children and adults: a formidable foe.Lancet Glob Health. 2017; 5: e1166-e1167Summary Full Text Full Text PDF PubMed Scopus (12) Google Scholar One can therefore intuit that, besides the cost-benefit in future productivity, a more immediate and medium-term cost-benefit would be seen, because of decreased transmission and herd immunity, diminished use of antimicrobials (particularly of new, expensive compounds), and reduced health-care consultations and hospitalisations (obviating the need for a public health response due to Shigella outbreaks and limiting the indirect costs on households by containing income losses while caring for sick children). Historically, the introduction of new vaccines has been based upon short-term economic decisions, such as health-care costs saved and the national impact of income losses prevented (due to parents caring for sick children), or alternatively on the number of disability-adjusted life years (DALYs) averted,5Deogaonkar R Hutubessy R van der Putten I Evers S Jit M Systematic review of studies evaluating the broader economic impact of vaccination in low and middle income countries.BMC Public Health. 2012; 12: 878Crossref PubMed Scopus (77) Google Scholar but a comprehensive analysis of the benefits of vaccines in the short, medium, and long term would be more realistic in delineating the true societal benefits. Income losses in LICs and LMICs due to LGF have been estimated at US$176·8 billion per birth cohort (or $616·5 billion at purchasing power parity rates), while lost educational attainment corresponds to 69·4 million years.6Fink G Peet E Danaei G et al.Schooling and wage income losses due to early-childhood growth faltering in developing countries: national, regional, and global estimates.Am J Clin Nutr. 2016; 104: 104-112Summary Full Text Full Text PDF PubMed Scopus (54) Google Scholar With improvements in the quality of water, sanitation, and hygiene (WaSH)—between 1990 and 2017, diarrhoeal deaths in children younger than 5 years decreased by a substantial 13·3% globally due to improved sanitation alone7GBD 2017 Diarrhoeal Disease CollaboratorsQuantifying risks and interventions that have affected the burden of diarrhoea among children younger than 5 years: an analysis of the Global Burden of Disease Study 2017.Lancet Infect Dis. 2020; 20: 37-59Summary Full Text Full Text PDF PubMed Scopus (72) Google Scholar—an even greater effect on LGF and productivity can be expected. Poor nutrition can impact childhood diarrhoea mortality, and accounted for the greatest number of deaths due to diarrhoea in this age group (69·3%) in the Global Enteric Multicenter Study; likewise, improving nutrition would also lead to a decrease in LGF.8Brander RL Pavlinac PB Walson JL et al.Determinants of linear growth faltering among children with moderate-to-severe diarrhea in the Global Enteric Multicenter Study.BMC Med. 2019; 17: 214Crossref PubMed Scopus (12) Google Scholar For a realistic overview, however, the true contribution of LGF needs to be appreciated in context. Recent evidence from combined data in birth cohort studies in six emerging economies indicates that the first 1000 days of life are particularly important for learning and development, and LGF might affect both schooling attainment and intelligence quotient (IQ) scores during this period.9Poveda NE Hartwig FP Victora CG et al.Patterns of growth in childhood in relation to adult schooling attainment and intelligence quotient in 6 birth cohorts in low- and middle-income countries: evidence from the Consortium of Health-Oriented Research in Transitioning Societies (COHORTS).J Nutr. 2021; 151: 2342-2352Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar However, the effect of early-life stature on schooling and adult IQ is attenuated when controlling for childhood IQ.10Stein AD Adair LS Donati G et al.Early-life stature, preschool cognitive development, schooling attainment, and cognitive functioning in adulthood: a prospective study in four birth cohorts.Lancet Glob Health. 2023; 11: e95-104Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar To realistically ensure that our future generations attain their full educational and economic potential, a multipronged approach that includes vaccination, timely and accurate diagnosis of disease, nutrition, WaSH, and promotion of cognitive stimulation is needed.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar, 10Stein AD Adair LS Donati G et al.Early-life stature, preschool cognitive development, schooling attainment, and cognitive functioning in adulthood: a prospective study in four birth cohorts.Lancet Glob Health. 2023; 11: e95-104Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar Increasing life expectancy globally combined with a decreasing birth rate in many countries has resulted in a significant shift in the global age distribution from 1990 to 2020, changing the population pyramid into a shape resembling a bullet, and we risk having too few economically active individuals to support the global population of the future. Lest we shoot ourselves in the foot, perhaps we need to reconsider how we regard our children: not simply as the most vulnerable of our society, but to remind ourselves that they are the future health-care workers who will care for us, the engineers and scientists who will further develop new vaccines, WaSH, and diagnostic tools for infectious diseases, the educators and entrepreneurs who will ensure sustainability in economic productivity, and the leaders who would strive for a better world for all. We declare no competing interests. Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling studyLGF is a secondary outcome of Shigella infection and reduction in LGF is not often quantified as a health or economic benefit of vaccination. However, even under conservative assumptions, a Shigella vaccine only moderately effective against LGF could pay for itself from productivity gains alone in some regions. We recommend that LGF be considered in future models assessing the economic and health impacts of interventions preventing enteric infections. Further research is needed on vaccine efficacy against LGF to inform such models. Full-Text PDF Open Access

A Description of the Statistical Methods for the Vaccine Impact on Diarrhea in Africa (VIDA) Study

Diarrheal diseases remain a health threat to children in low- and middle-income countries. The Vaccine Impact on Diarrhea in Africa (VIDA) study was a 36-month, prospective, matched case-control study designed to estimate the etiology, incidence, and adverse clinical consequences of moderate-to-severe diarrhea (MSD) in children aged 0-59 months. VIDA was conducted following rotavirus vaccine introduction at 3 censused sites in sub-Saharan Africa that participated in the Global Enteric Multicenter Study (GEMS) ∼10 years earlier. We describe the study design and statistical methods of VIDA and where they differ from GEMS. We aimed to enroll 8-9 MSD cases every 2 weeks from sentinel health centers in 3 age strata (0-11, 12-23, 24-59 months) and 1 to 3 controls matched by age, sex, date of case enrollment, and village. Clinical, epidemiological, and anthropometric data were collected at enrollment and ∼60 days later. A stool specimen collected at enrollment was analyzed by both conventional methods and quantitative PCR for enteric pathogens. For the matched case-control study, we estimated the population-based, pathogen-specific attributable fraction (AF) and attributable incidence adjusted for age, site, and other pathogens, and identified episodes attributable to a specific pathogen for additional analyses. A prospective cohort study nested within the original matched case-control study allowed assessment of (1) the association between potential risk factors and outcomes other than MSD status and (2) the impact of MSD on linear growth. GEMS and VIDA together comprise the largest and most comprehensive assessment of MSD conducted to date in sub-Saharan Africa populations at highest risk for morbidity and mortality from diarrhea. The statistical methods used in VIDA have endeavored to maximize the use of available data to produce more robust estimates of the pathogen-specific disease burden that might be prevented by effective interventions.

Prevalence ofSalmonellain Stool During the Vaccine Impact on Diarrhea in Africa (VIDA) Study, 2015–2018

Non-typhoidal Salmonella (NTS) is a common cause of gastroenteritis in young children, with limited data on NTS serovars and antimicrobial resistance in Africa. We determined the prevalence of Salmonella spp. and frequency of antimicrobial resistance among serovars identified in stools of 0-59 month-old children with moderate-to-severe diarrhea (MSD) and controls enrolled in the Vaccine Impact on Diarrhea in Africa (VIDA) Study in The Gambia, Mali, and Kenya in 2015-2018, and compared with data from the Global Enteric Multicenter Study (GEMS; 2007-2010) and the GEMS-1A study (2011). Salmonella spp. was detected by quantitative real-time PCR (qPCR) and culture-based methods. Identification of serovars was determined by microbiological methods. By qPCR, the prevalence of Salmonella spp. among MSD cases was 4.0%, 1.6%, and 1.9% and among controls was 4.6%, 2.4%, and 1.6% in The Gambia, Mali, and Kenya, respectively, during VIDA. We observed year-to-year variation in serovar distribution and variation between sites. In Kenya, Salmonella enterica serovar Typhimurium decreased (78.1% to 23.1%; P < .001) among cases and controls from 2007 to 2018, whereas serogroup O:8 increased (8.7% to 38.5%; P = .04). In The Gambia, serogroup O:7 decreased from 2007 to 2018 (36.3% to 0%; P = .001) but S. enterica serovar Enteritidis increased during VIDA (2015 to 2018; 5.9% to 50%; P = .002). Only 4 Salmonella spp. were isolated in Mali during all 3 studies. Multidrug resistance was 33.9% in Kenya and 0.8% in The Gambia across all 3 studies. Ceftriaxone resistance was only observed in Kenya (2.3%); NTS isolates were susceptible to ciprofloxacin at all sites. Understanding variability in serovar distribution will be important for the future deployment of vaccines against salmonellosis in Africa.

Etiology, Presentation, and Risk Factors for Diarrheal Syndromes in 3 Sub-Saharan African Countries After the Introduction of Rotavirus Vaccines From the Vaccine Impact on Diarrhea in Africa (VIDA) Study

Diarrheal disease is heterogeneous, including watery diarrhea (WD) and dysentery, some cases of which become persistent diarrhea (PD). Changes in risk over time necessitate updated knowledge of these syndromes in sub-Saharan Africa. The Vaccine Impact on Diarrhea in Africa (VIDA) study was an age-stratified, case-control study of moderate-to-severe diarrhea among children <5 years old in The Gambia, Mali, and Kenya (2015-2018). We analyzed cases with follow-up of about 60 days after enrollment to detect PD (lasting ≥14 days), examined the features of WD and dysentery, and examined determinants for progression to and sequelae from PD. Data were compared with those from the Global Enteric Multicenter Study (GEMS) to detect temporal changes. Etiology was assessed from stool samples using pathogen attributable fractions (AFs), and predictors were assessed using χ2 tests or multivariate regression, where appropriate. Among 4606 children with moderate-to-severe diarrhea, 3895 (84.6%) had WD and 711 (15.4%) had dysentery. PD was more frequent among infants (11.3%) than in children 12-23 months (9.9%) or 24-59 months (7.3%), P = .001 and higher in Kenya (15.5%) than in The Gambia (9.3%) or Mali (4.3%), P < .001; the frequencies were similar among children with WD (9.7%) and those with dysentery (9.4%). Compared to children not treated with antibiotics, those who received antibiotics had a lower frequency of PD overall (7.4% vs 10.1%, P = .01), and particularly among those with WD (6.3% vs 10.0%; P = .01) but not among children with dysentery (8.5% vs 11.0%; P = .27). For those with watery PD, Cryptosporidium and norovirus had the highest AFs among infants (0.16 and 0.12, respectively), while Shigella had the highest AF (0.25) in older children. The odds of PD decreased significantly over time in Mali and Kenya while increasing significantly in The Gambia. The burden of PD endures in sub-Saharan Africa, with nearly 10% of episodes of WD and dysentery becoming persistent.

Stunting Following Moderate-to-Severe Diarrhea Among Children Aged &amp;lt;5 Years in Africa Before and After Rotavirus Vaccine Introduction: A Comparison of the Global Enteric Multicenter Study and the Vaccine Impact on Diarrhea in Africa (VIDA) Study

Studies conducted before rotavirus vaccine introduction found that moderate-to-severe diarrhea (MSD) in children aged <5 years was associated with stunting at follow-up. It is unknown whether the reduction in rotavirus-associated MSD following vaccine introduction decreased the risk of stunting. The Global Enteric Multicenter Study (GEMS) and the Vaccine Impact on Diarrhea in Africa (VIDA) study, two comparable matched case-control studies, were conducted during 2007-2011 and 2015-2018, respectively. We analyzed data from 3 African sites where rotavirus vaccine was introduced after GEMS and before starting VIDA. Children with acute MSD (<7 days onset) were enrolled from a health center and children without MSD (diarrhea-free for ≥7 days) were enrolled at home within 14 days of the index MSD case. The odds of being stunted at a follow-up visit 2-3 months after enrollment for an episode of MSD was compared between GEMS and VIDA using mixed-effects logistic regression models controlling for age, sex, study site, and socioeconomic status. We analyzed data from 8808 children from GEMS and 10 579 from VIDA. Among those who were not stunted at enrollment in GEMS, 8.6% with MSD and 6.4% without MSD became stunted during the follow-up period. In VIDA, 8.0% with MSD and 5.5% children without MSD developed stunting. An episode of MSD was associated with higher odds of being stunted at follow-up compared with children without MSD in both studies (adjusted odds ratio [aOR], 1.31; 95% confidence interval [CI]: 1.04-1.64 in GEMS and aOR, 1.30; 95% CI: 1.04-1.61 in VIDA). However, the magnitude of association was not significantly different between GEMS and VIDA (P = .965). The association of MSD with subsequent stunting among children aged <5 years in sub-Saharan Africa did not change after rotavirus vaccine introduction. Focused strategies are needed for prevention of specific diarrheal pathogens that cause childhood stunting.

Genomic diversity of non-diarrheagenic fecal Escherichia coli from children in sub-Saharan Africa and south Asia and their relatedness to diarrheagenic E. coli

Escherichia coli is a frequent member of the healthy human gastrointestinal microbiota, as well as an important human pathogen. Previous studies have focused on the genomic diversity of the pathogenic E. coli and much remains unknown about the non-diarrheagenic E. coli residing in the human gut, particularly among young children in low and middle income countries. Also, gaining additional insight into non-diarrheagenic E. coli is important for understanding gut health as non-diarrheagenic E. coli can prevent infection by diarrheagenic bacteria. In this study we examine the genomic diversity of non-diarrheagenic fecal E. coli from male and female children with or without diarrhea from countries in sub-Saharan Africa and south Asia as part of the Global Enteric Multicenter Study (GEMS). We find that these E. coli exhibit considerable genetic diversity as they were identified in all E. coli phylogroups and an Escherichia cryptic clade. Although these fecal E. coli lack the characteristic virulence factors of diarrheagenic E. coli pathotypes, many exhibit remarkable genomic similarity to previously described diarrheagenic isolates with differences attributed to mobile elements. This raises an important question of whether these non-diarrheagenic fecal E. coli may have at one time possessed the mobile element-encoded virulence factors of diarrheagenic pathotypes or may have the potential to acquire these virulence factors.

Clinical Prediction Rule to Guide Diagnostic Testing for Shigellosis and Improve Antibiotic Stewardship for Pediatric Diarrhea.

Diarrheal diseases are a leading cause of death for children aged <5 years. Identification of etiology helps guide pathogen-specific therapy, but availability of diagnostic testing is often limited in low-resource settings. Our goal is to develop a clinical prediction rule (CPR) to guide clinicians in identifying when to use a point-of-care (POC) diagnostic for Shigella in children presenting with acute diarrhea. We used clinical and demographic data from the Global Enteric Multicenter Study (GEMS) study to build predictive models for diarrhea of Shigella etiology in children aged ≤59 months presenting with moderate to severe diarrhea in Africa and Asia. We screened variables using random forests, and assessed predictive performance with random forest regression and logistic regression using cross-validation. We used the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) study to externally validate our GEMS-derived CPR. Of the 5011 cases analyzed, 1332 (27%) had diarrhea of Shigella etiology. Our CPR had high predictive ability (area under the receiver operating characteristic curve = 0.80 [95% confidence interval, .79-.81]) using the top 2 predictive variables, age and caregiver-reported bloody diarrhea. We show that by using our CPR to triage who receives diagnostic testing, 3 times more Shigella diarrhea cases would have been identified compared to current symptom-based guidelines, with only 27% of cases receiving a POC diagnostic test. We demonstrate how a CPR can be used to guide use of a POC diagnostic test for diarrhea management. Using our CPR, available diagnostic capacity can be optimized to improve appropriate antibiotic use.

1540. Clinical severity across five viral diarrheal pathogens in infants and young children Global Enteric Multicenter Study (GEMS)

Abstract Background Viruses are a leading cause of pediatric diarrheal illness, resulting in over 200,000 childhood deaths annually worldwide. Rotavirus is the most common viral cause of moderate-to-severe diarrhea in low to middle-income countries, but adenovirus 40/41, norovirus, sapovirus, and astrovirus are increasingly recognized as important contributors to the global viral gastroenteritis burden. Comparisons of clinical severity between these five viruses among infants and young children are currently limited. Methods The objective of this analysis was to describe the clinical severity of rotavirus, adenovirus 40/41, norovirus, sapovirus, and astrovirus among children enrolled in the Global Enteric Multicenter Study (GEMS). Stool samples from children younger than 5 years of age with moderate-to-severe diarrhea at four sites in Africa and three in Asia were tested by enzyme immunoassays (rotavirus, adenovirus) and multiplex reverse transcriptase polymerase chain reaction (norovirus, sapovirus, astrovirus). A modified Vesikari score (MVS) to assess clinical severity was calculated based on symptoms and clinical characteristics. Results Among 3,305 viral diarrhea cases, rotavirus had the highest median MVS (9 [interquartile range [IQR: 7,11]) followed by adenovirus 40/41 (8 [IQR]: 6,10]); sapovirus and astrovirus had a similar MVS distribution to norovirus (7 [IQR: 6, 9]). The proportion of patients experiencing &amp;gt; 3 episodes of vomiting was high for those with rotavirus (66.3%) and adenovirus 40/41 (55.7%); astrovirus (40.8%), sapovirus (40.0%), and norovirus (35.9%) patients also experienced substantial episodes of vomiting. A high proportion of cases with adenovirus 40/41 (54.0%) and rotavirus (46.3%) experienced ≥ 7 episodes of diarrhea within 24 hours. While hospitalization or intravenous fluids were required most frequently for patients with rotavirus (42.1%), the proportion was also high in those with adenovirus 40/41 (30.6%). Conclusion These findings demonstrate the clinical severity of viral diarrheal pathogens besides rotavirus, in particular adenovirus 40/41, warranting the continued development of vaccines and therapeutics to prevent morbidity and mortality due to viral enteric pathogens. Disclosures All Authors: No reported disclosures.

Mucosal Immune Profiles Associated with Diarrheal Disease Severity in Shigella- and Enteropathogenic Escherichia coli-Infected Children Enrolled in the Global Enteric Multicenter Study.

ABSTRACTEnteropathogenic Escherichia coli (EPEC) and Shigella are etiologic agents of diarrhea in children <5 years old living in resource-poor countries. Repeated bouts of infection lead to lifelong morbidity and even death. The goal of this study was to characterize local mucosal immune responses in Shigella- and EPEC-infected children <5 years of age with moderate to severe diarrhea (MSD) enrolled in the Global Enteric Multicenter Study (GEMS). We hypothesized that infection with each of these pathogens would induce distinct gut mucosal immune profiles indicative of disease etiology and severity. To test this hypothesis, innate and adaptive immune markers were measured in stools from children with diarrhea due to EPEC, Shigella, or other organisms and in children who had no diarrhea. Shigella-positive diarrhea evoked robust proinflammatory and TH1/TH2 cytokine responses compared to diarrhea caused by EPEC or other organisms, with the exception of interleukin 5 (IL-5), which was associated with EPEC infection. The presence of IL-1β, IL-4, IL-16, and tumor necrosis factor beta (TNF-β) was associated with the absence of dysentery. EPEC-positive diarrhea evoked high levels of IL-1β, vascular endothelial growth factor (VEGF), and IL-10. Granulocyte-macrophage colony-stimulating factor (GM-CSF) had opposing roles in disease severity, being associated with absence of diarrhea in EPEC-infected children and with dysenteric Shigella infection. High levels of antigen-specific antibodies were detected in the controls and children with Shigella without dysentery, which suggests a protective role against severe disease. In summary, this study identified distinct local immune responses associated with two clinically relevant diarrheagenic pathogens, Shigella and EPEC, in children and identified protective immune phenotypes that can inform the development of preventive measures.

The role of CFA/I in adherence and toxin delivery by ETEC expressing multiple colonization factors in the human enteroid model.

Enterotoxigenic Escherichia coli (ETEC) is a primary causative agent of diarrhea in travelers and young children in low-to-middle-income countries (LMICs). ETEC adhere to intestinal epithelia via colonization factors (CFs) and secrete heat-stable toxin (ST) and/or heat-labile toxin (LT), causing dysregulated cellular ion transport and water secretion. ETEC isolates often harbor genes encoding more than one CF that are targets as vaccine antigens. CFA/I is a major CF that is associated with ETEC that causes moderate-to-severe diarrhea and plays an important role in pathogenesis. The Global Enteric Multicenter Study finding that 78% of CFA/I-expressing ETEC also encode the minor CF CS21 prompted investigation of the combined role of these two CFs. Western blots and electron microscopy demonstrated growth media-dependent and strain-dependent differences in CFA/I and CS21 expression. The critical role of CFA/I in adherence by ETEC strains expressing CFA/I and CS21 was demonstrated using the human enteroid model and a series of CFA/I- and CS21-specific mutants. Furthermore, only anti-CFA/I antibodies inhibited adherence by global ETEC isolates expressing CFA/I and CS21. Delivery of ST and resulting cGMP secretion was measured in supernatants from infected enteroid monolayers, and strain-specific ST delivery and time-dependent cGMP production was observed. Interestingly, cGMP levels were similar across wildtype and CF-deficient strains, reflecting a limitation of this static aerobic infection model. Despite adherence by ETEC and delivery of ST, the enteroid monolayer integrity was not disrupted, as shown by the lack of decrease in transepithelial electrical resistance and the lack of IL-8 cytokines produced during infection. Taken together, these data demonstrate that targeting CFA/I in global clinical CFA/I-CS21 strains is sufficient for adherence inhibition, supporting a vaccine strategy that focuses on blocking major CFs. In addition, the human enteroid model has significant utility for the study of ETEC pathogenesis and evaluation of vaccine-induced functional antibody responses.

Association between Pathogenic Variants of Diarrheagenic Escherichia coli and Growth in Children under 5 Years of Age in the Global Enteric Multicenter Study.

ABSTRACT.There is a lack of information highlighting associations between different pathogenic variants of diarrheagenic Escherichia coli and childhood growth. Pathogenic variants of E. coli from stool samples, collected from 22,567 children enrolled in the Global Enteric Multicenter Study from December 2007 to March 2011, were detected by real-time polymerase chain reaction. We estimated the associations of different pathogenic variants of diarrheagenic E. coli with child growth. The association between an explanatory variable and the outcome variable was assessed using multiple linear regression, where the dependent variables were height-for-age, weight-for-age, and weight-for-height z-scores, and the independent variable was the presence of different pathogenic variants of diarrheagenic E. coli. After adjusting for potential covariates, such as age, gender, diarrhea, breastfeeding status, mother’s education, number of under-5 children, handwashing practice, handwashing material, source of drinking water, wealth index, available toilet facility, copathogens, comorbidity, time, and study site, the multivariable model identified a negative association between different pathogenic variants of diarrheagenic E. coli and child growth. Our analyses may provide the cornerstone for prospective epidemiologic investigation for the development of preventive measures for diarrheagenic E. coli and combat childhood undernutrition.

Pathogenomic analyses of Shigella isolates inform factors limiting shigellosis prevention and control across LMICs

Shigella spp. are the leading bacterial cause of severe childhood diarrhoea in low- and middle-income countries (LMICs), are increasingly antimicrobial resistant and have no widely available licenced vaccine. We performed genomic analyses of 1,246 systematically collected shigellae sampled from seven countries in sub-Saharan Africa and South Asia as part of the Global Enteric Multicenter Study (GEMS) between 2007 and 2011, to inform control and identify factors that could limit the effectiveness of current approaches. Through contemporaneous comparison among major subgroups, we found that S. sonnei contributes ≥6-fold more disease than other Shigella species relative to its genomic diversity, and highlight existing diversity and adaptative capacity among S. flexneri that may generate vaccine escape variants in <6 months. Furthermore, we show convergent evolution of resistance against ciprofloxacin, the current WHO-recommended antimicrobial for the treatment of shigellosis, among Shigella isolates. This demonstrates the urgent need to integrate existing genomic diversity into vaccine and treatment plans for Shigella, providing a framework for the focused application of comparative genomics to guide vaccine development, and the optimization of control and prevention strategies for other pathogens relevant to public health policy considerations.

Anthropometric Indices of Giardia-Infected Under-Five Children Presenting with Moderate-to-Severe Diarrhea and Their Healthy Community Controls: Data from the Global Enteric Multicenter Study.

Among all intestinal parasitosis, giardiasis has been reported to be associated with delayed growth in malnourished children under 5 living in low- and middle-income countries. Relevant data on the nutritional status of children aged 0–59 months presenting with moderate-to-severe diarrhea (MSD) and giardia infection were collected from sentinel health facilities of the Global Enteric Multicenter Study’s (GEMS) seven field settings, placed in diverse countries of Sub-Saharan Africa and South Asia between, December 2007 and February 2011. Then, this study analyzed a robust dataset of study participants (n = 22,569). Children having giardiasis with MSD constituted as cases (n = 1786), and those without MSD constituted as controls (n = 3470). Among the seven field sites, symptomatic giardiasis was 15% and 22% in Asian and African sites, respectively, whereas asymptomatic giardia infection (healthy without MSD) in Asian and African sites was 21.7% and 30.7%, respectively. Wasting and underweight were more frequently associated and stunting less often associated with symptomatic giardiasis (for all, p < 0.001). Symptomatic giardiasis had a significant association with worsening of nutritional status in under-five children. Improved socio-economic profile along with proper sanitation and hygienic practices are imperative to enhance child nutritional status, particularly in resource limited settings.

Nontyphoidal Salmonella among Children under 5 Years Old in Sub-Saharan Africa and South Asia in the Global Enteric Multicenter Study.

ABSTRACT.Factors associated with nontyphoidal Salmonella (NTS) infection have not been well characterized to date. We aimed to compare the associated factors among children under age 5 years with NTS infection in sub-Saharan Africa and South Asia. Data from children having moderate-to-severe diarrhea (MSD) and asymptomatic children with NTS isolated from fecal specimens were extracted from the Global Enteric Multicenter Study (GEMS), conducted from December 2007 to March 2011. Compared with NTS-negative children, NTS-associated MSD cases in South Asia were associated with the presence of goat in the house (adjusted odds ratio [aOR]: 2.15; 95% confidence interval [CI]: 1.25–3.70) and handwashing after handling an animal (aOR: 2.26; 95% CI: 1.36–3.74). In sub-Saharan Africa, children with NTS associated MSD had a greater association with stunting (1.21 95% CI: 1.01–1.45), longer duration of diarrhea (aOR: 1.25 95% CI: 1.19–1.31); presence of cow in house (aOR: 1.54 95% CI: 1.09–2.16), handwashing after handling animal (aOR: 2.41 95% CI: 1.74–3.33). Drinking tube well water (aOR: 0.54 95% CI: 0.32–0.91), availability of toilet facility (aOR: 0.58 95% CI: 0.53–0.65), and handwashing before eating (aOR: 0.76 95% CI: 0.57–1.00) and after defecation (aOR: 0.80 95% CI: 0.69, 0.94) were found to be protective. The differentials between children of both regions having fecal NTS are distinct and underscore the need for policymaking for preventive and control strategies targeting stunted children.