Burden Of Diarrheal Disease Research Articles

Prevalence of Antibiotic Resistant Bacteria in Nigerian Fermented Food Condiments

Food borne diseases remain a growing public health problem gotten through the consumption of contaminated food and water. A world health organization report, 2015 estimated 600million episodes of illness due to contaminated food worldwide. Amongst all age groups, Africa bore the greatest burden of diarrhoeal diseases. Gram-negative bacteria have become a significant challenge to the control of infection as a result of acquisition of antibiotic resistant genes. This is especially of concern in Nigeria where fermented condiments are important part of daily meals and sometimes consumed without cooking. This work thus identifies Gram negative bacteria from fermented condiments and evaluates the antibiotic resistance profile of the bacterial isolates. The fermented condiments- Iru (Parkia biglobosa) (67), Ogiri-igbo (Ricinus communis) (58), Ukpaka (Pentaclethra macrophylla) (22) and Okpei (Prosopis africana) (42), were obtained from markets in Abuja, Gboko, Lokoja, Okenne, Abeokuta, Ibadan, Ijebu-Ode, Ilorin, Lagos, Ondo and Ore. Coliform and faecal coliform test was done. Isolation of the Gram-negative bacteria was done using MacConkey agar. Taxonomic studies were carried out on the isolated Gram negative bacteria. Determination of antibiotic resistance profile of the Gram-negative bacteria was done by disc diffusion method. Ukpaka (Pentaclethra macrophylla) samples had the highest percentage occurrence of coliforms (100%). Faecal coliform were more prevalent in Ukpaka (20%) and Iru (16.67%). Klebsiella pneumonia was prevalent in the 3 of the fermented condiments (Iru, Ogiri and Ukpaka). Escherichia coli was the most frequent Gram-negative bacteria in Okpei samples. The relatively high recovery rates of Gram-negative bacteria shows possible contamination of fermented condiments by human pathogens. The isolates from Ukpaka showed the highest resistance (55.3%) to Cotrimoxazole. The effect of the resistance of Gram-negative bacteria to antibiotics could be transmission of resistant strains from farm to house, treatment failure and a limited choice of antibiotics used for treatment.

Burden of typhoid fever and cholera: similarities and differences. Prevention strategies for European travelers to endemic/epidemic areas.

SummaryThe burden of diarrheal diseases is very high, accounting for 1.7 to 5 billion cases per year worldwide. Typhoid fever (TF) and cholera are potentially life-threatening infectious diseases, and are mainly transmitted through the consumption of food, drink or water that have been contaminated by the feces or urine of subjects excreting the pathogen. TF is mainly caused by Salmonella typhi, whereas cholera is caused by intestinal infection by the toxin-producing bacterium Vibrio cholerae. These diseases typically affect low- and middle-income countries where housing is overcrowded and water and sanitation are poor, or where conflicts or natural disasters have led to the collapse of the water, sanitation and healthcare systems. Mortality is higher in children under 5 years of age. Regarding their geographical distribution, TF has a high incidence in sub-Saharan Africa, India and south-east Asia, while cholera has a high incidence in a few African countries, particularly in the Horn of Africa and the Arabian Peninsula.In the fight against these diseases, preventive measures are fundamental.With modern air travel, transmissible diseases can spread across continents and oceans in a few days, constituting a threat to global public health. Nowadays, people travel for many reasons, such as tourism and business. Several surveys have shown that a high proportion of travelers lack adequate information on safety issues, such as timely vaccination and prophylactic medications. The main objective of this overview is to provide information to help European travelers to stay healthy while abroad, and thus also to reduce the potential importation of these diseases and their consequent implications for public health and society.The preventive measures to be implemented in the case of travel to countries where these diseases are still endemic are well known: the adoption of safe practices and vaccinations. It is important to stress that an effective preventive strategy should be based both on vaccinations and on hygiene travel guidelines.Furthermore, the emergence of multidrug-resistant strains is becoming a serious problem in the clinical treatment of these diseases. For this reason, vaccination is the main solution.

Diarrheal correlates associated with enteric bacterial infections among children below five years in Murang'a County, Kenya.

IntroductionThe burden of childhood diarrheal disease has resulted in massive mortality and morbidity globally. Children below 5 years in sub-Saharan Africa are most implicated by diarrheal illnesses resulting in numerous medical consultations, admissions, and deaths despite the disease being easy to prevent and control. The study aimed to determine the correlates of enteric bacterial infection causing diarrhea.MethodsDuring the months of April-October 2017, 163 children below five years presenting with diarrhea were randomly selected in Murang'a and Muriranja's hospitals. Bacterial agents were identified and correlates of diarrhea determined. The study used a hospital-based cross-sectional study design. A standardized questionnaire was used to collect information from the guardian. Statistical analyses were performed using STATA v. 13.ResultsForty-nine children were infected with enteric pathogenic bacteria (Enterotoxigenic Escherichia coli, Enteropathogenic Escherichia coli, Enteroaggregative Escherichia coli, Salmonella, Shigella, and Vibrio species). Factors associated with infection by these bacteria among the 49 children were evaluated. Children between 0-12 months (OR 0.3, 95% CI 0.1-0.8), those fed exclusively on breast milk (OR 0.3, 95% CI 0.09-0.9) and children weighing 1-5 kilograms (OR 0.2, 95% CI 0.04-0.9) were less likely to be infected with these enteric pathogenic bacteria. Female participants (OR 1.8, 95% CI 1.1-3.4) were nearly twice likely to be infected with enteric pathogenic bacteria. Children who presented with watery stool (OR 0.4, 95% CI 0.2-0.9) or mucoid stool (OR 0.3, 95% CI 0.2-0.7) remained associated with enteric pathogenic bacterial infection but less likely to be infected compared to those who presented with watery-blood stained stools. Piped water (OR 0.01, 95% CI 0.01-0.4) was less associated with enteric bacterial infection than water stored in jerry-cans while storing water without a lid (OR 1.9, 95% CI 1.1-3.7) was more likely to lead to bacterial infection. Hand washing after toilet use (OR 1.6, 95% CI 1.1-2.7) was associated with enteric bacterial infection compared to hand washing before meal preparation.ConclusionSanitation, hygiene, nutritional and clinical factors were associated with enteric bacterial infections causing diarrhea among children below five years in the study area. Childhood diarrhea in Murang'a County is a major public health problem.

Predicting quality and quantity of water used by urban households based on tap water service

Despite significant progress in improving access to safe water globally, inadequate access remains a major public health concern in low- and middle-income countries. We collected data on the bacterial quality of stored drinking water and the quantity of water used domestically from 416 households in Uvira, Democratic Republic of the Congo. An indicator of tap water availability was constructed using invoices from 3685 georeferenced piped water connections. We examined how well this indicator predicts the probability that a household’s stored drinking water is contaminated with Escherichia coli, and the total amount of water used at home daily, accounting for distance from alternative surface water sources. Probability of drinking water contamination is predicted with good discrimination overall, and very good discrimination for poorer households. More than 80% of the households are predicted to store contaminated drinking water in areas closest to the rivers and with the worst tap water service, where river water is also the most likely reported source of drinking water. A model including household composition predicts nearly two-thirds of the variability in the reported quantity of water used daily at home. Households located near surface water and with a poor tap water service indicator are more likely to use water directly at the source. Our results provide valuable information that supports an ongoing large-scale investment in water supply infrastructure in Uvira designed to reduce the high burden of cholera and other diarrhoeal diseases. This approach may be useful in other urban settings with limited water supply access.

Faecal neutrophil elastase-antiprotease balance reflects colitis severity

Given the global burden of diarrheal diseases on healthcare it is surprising how little is known about the drivers of disease severity. Colitis caused by infection and inflammatory bowel disease (IBD) is characterised by neutrophil infiltration into the intestinal mucosa and yet our understanding of neutrophil responses during colitis is incomplete. Using infectious (Citrobacter rodentium) and chemical (dextran sulphate sodium; DSS) murine colitis models, as well as human IBD samples, we find that faecal neutrophil elastase (NE) activity reflects disease severity. During C. rodentium infection intestinal epithelial cells secrete the serine protease inhibitor SerpinA3N to inhibit and mitigate tissue damage caused by extracellular NE. Mice suffering from severe infection produce insufficient SerpinA3N to control excessive NE activity. This activity contributes to colitis severity as infection of these mice with a recombinant C. rodentium strain producing and secreting SerpinA3N reduces tissue damage. Thus, uncontrolled luminal NE activity is involved in severe colitis. Taken together, our findings suggest that NE activity could be a useful faecal biomarker for assessing disease severity as well as therapeutic target for both infectious and chronic inflammatory colitis.

Incidence and etiology of infectious diarrhea from a facility-based surveillance system in Guatemala, 2008\u20132012

BackgroundDiarrhea is a major cause of morbidity and mortality, yet incidence and etiology data are limited. We conducted laboratory-based diarrhea surveillance in Guatemala.MethodsA diarrhea case was defined as ≥3 loose stools in a 24-h period in a person presenting to the surveillance facilities. Epidemiologic data and stool specimens were collected. Specimens were tested for bacterial, parasitic, and viral pathogens. Yearly incidence was adjusted for healthcare seeking behaviors determined from a household survey conducted in the surveillance catchment area.ResultsFrom November 2008 to December 2012, the surveillance system captured 5331 diarrhea cases; among these 1381 (26%) had specimens tested for all enteric pathogens of interest. The adjusted incidence averaged 659 diarrhea cases per 10,000 persons per year, and was highest among children aged < 5 years, averaging 1584 cases per 10,000 children per year. Among 1381 (26%) specimens tested for all the pathogens of interest, 235 (17%) had a viral etiology, 275 (20%) had a bacterial, 50 (4%) had parasites, and 86 (6%) had co-infections. Among 827 (60%) specimens from children aged < 5 years, a virus was identified in 196 (23%) patients; 165 (20%) had norovirus and 99 (12%) rotavirus, including co-infections. Among 554 patients aged ≥5 years, 103 (19%) had a bacterial etiology, including diarrheagenic Escherichia coli in 94 (17%) cases, Shigella spp. in 31 (6%), Campylobacter spp. in 5 (1%), and Salmonella spp. in 4 (1%) cases. Detection of Giardia and Cryptosporidium was infrequent (73 cases; 5%).ConclusionsThere was a substantial burden of viral and bacterial diarrheal diseases in Guatemala, highlighting the importance of strengthening laboratory capacity for rapid detection and control and for evaluation of public health interventions.

Heterogeneity in potential impact and cost-effectiveness of ETEC and Shigella vaccination in four sub-Saharan African countries

Diarrheal disease burden has become more heterogenous in low- and lower middle-income countries as access to clean water, sanitation and health care has increased in wealthier urban populations. Enterotoxigenic Escherichia coli (ETEC) and Shigella are among the top five causes of diarrheal mortality in children living in sub-Saharan Africa.Here, we explored how accounting for subnational and economic heterogeneity in ETEC and Shigella disease burden affects projected vaccine impact and cost-effectiveness of standalone ETEC and Shigella vaccines during the first decade after introduction in four sub-Saharan African countries. We developed dynamic models for provincial areas and socioeconomic subpopulations of children in the Democratic Republic of Congo (DRC), Kenya, Zambia, and Zimbabwe. We estimated deaths and morbidity due to ETEC and Shigella diarrhea plus additional deaths from other infectious diseases attributable to ETEC- and Shigella-induced stunting. We analyzed cost-effectiveness using Incremental Cost-Effectiveness Ratios (ICERs) with Disability-Adjusted Life Years (DALYs) and Moderate-and-Severe Diarrheal episodes (MSD) averted as denominators.Other infectious disease deaths due to induced stunting accounted for 9–28% and 9–32% of the total provincial level ETEC and Shigella disease burden, respectively, across these four countries from years 2025 to 2034. Our results indicated that the lowest and most cost-effective provincial DALYs averted ICERs were below $600 and $500/DALY averted for ETEC and Shigella vaccination, respectively in Zimbabwe. ICERs were the highest in Zambia and Kenya, where all provincial ICERs where above $2000/DALY. The highest national and provincial MSD averted ICERs were in DRC, while the lowest were in Kenya and Zimbabwe. Vaccinations were most cost-effective in averting DALYs in lower wealth subpopulations living in the highest burden provincial areas.Our approach focused on subnational heterogeneity in ETEC and Shigella burden and vaccination access found that impact and cost-effectiveness were more favorable if vaccinations reach the most vulnerable children in underserved provinces.

Assessing the effect of climate factors on childhood diarrhoea burden in Kathmandu, Nepal.

This study was undertaken to assess the effect of climate variability on diarrhoeal disease burden among children under 5 years of age living in Kathmandu, Nepal. The researchers sought to predict future risk of childhood diarrhoea under different climate change scenarios to advance the evidence base available to public health decision-makers, and the Nepalese infection control division, in planning for climate impacts. A time series study was conducted using the monthly case count of diarrhoeal disease (2003-2013) among children under 5 years of age living in Kathmandu, Nepal. A quasi Poisson generalised linear equation with distributed lag linear model was fitted to estimate the lagged effect of monthly maximum temperature and rainfall on childhood diarrhoea. The environmental framework of comparative risk assessment was used to assess the environmental burden of diarrhoea within this population. A total of 219,774 cases of diarrhoeal disease were recorded during the study period with a median value of 1286 cases per month. The results of a regression model revealed that the monthly count of diarrhoea cases increased by 8.1% (RR: 1.081; 95% CI: 1.02-1.14) per 1 °C increase in maximum temperature above the monthly average recorded within that month. Similarly, rainfall was found to have significant effect on the monthly diarrhoea count, with a 0.9% (RR; 1.009; 95% CI: 1.004-1.015) increase in cases for every 10 mm increase in rainfall above the monthly cumulative value recorded within that month. It was estimated that 7.5% (95% CI: 2.2%-12.5%) of the current burden of diarrhoea among children under 5 years of age could be attributed to climatic factors (maximum temperature), and projected that 1357 (UI: 410-2274) additional cases of childhood diarrhoea could be climate attributable by the year 2050 under low-risk scenario (0.9 °C increase in maximum temperature). It is estimated that there exists a significant association (p < 0.05) between childhood diarrhoea and an increase in maximum temperature and rainfall in Kathmandu, Nepal. The findings of this study may inform the conceptualization and design of early warning systems for the prediction and control of childhood diarrhoea, based upon the observed pattern of climate change in Kathmandu.

Linking Decision Theory and Quantitative Microbial Risk Assessment: Tradeoffs Between Compliance and Efficacy for Waterborne Disease Interventions.

Achieving health gains from the U.N. Sustainable Development Goals of universal coverage for water and sanitation will require interventions that can be widely adopted and maintained. Effectiveness-how an intervention performs based on actual use-as opposed to efficacy will therefore be central to evaluations of new and existing interventions. Incomplete compliance-when people do not always use the intervention and are therefore exposed to contamination-is thought to be responsible for the lower-than-expected risk reductions observed from water, sanitation, and hygiene interventions based on their efficacy at removing pathogens. We explicitly incorporated decision theory into a quantitative microbial risk assessment model. Specifically, we assume that the usability of household water treatment (HWT) devices (filters and chlorine) decreases as they become more efficacious due to issues such as taste or flow rates. Simulations were run to examine the tradeoff between device efficacy and usability. For most situations, HWT interventions that trade lower efficacy (i.e., remove less pathogens) for higher compliance (i.e., better usability) contribute substantial reductions in diarrheal disease risk compared to devices meeting current World Health Organization efficacy guidelines. Recommendations that take into account both the behavioral and microbiological properties of treatment devices are likely to be more effective at reducing the burden of diarrheal disease than current standards that only consider efficacy.

Environmental factors affecting childhood diarrheal disease among under-five children in Jamma district, South Wello zone, Northeast Ethiopia

BackgroundGlobally, diarrhea is the leading cause of morbidity and mortality among less than 5 years old children and it contributes to the deaths of approximately one million children every year. In Ethiopia, diarrhea is the second cause of under-five mortality and morbidity. However, in the study area, studies were limited. Therefore, this study has assessed the prevalence of diarrhea and associated factors among < 5 years of age in Jamma district, Northeast Ethiopia.MethodsA community-based cross-sectional study was conducted from August 15 to September 15, 2017, in Jamma district, South Wello zone, northeast Ethiopia. A Systematic random sampling technique was used to select 614 households and a pretested structured questionnaire was used to collect the data. A multivariable logistic regression analysis was used to investigate factors associated with diarrheal disease. Adjusted Odds Ratio (AOR) with the corresponding 95% Confidence Interval (CI) for variables with P-value < 0.05 was used to show statistically significant association.ResultsIn this study, the prevalence of diarrhea among under-five children was 23.1% (95% CI: (19.4, 26.5). Child’s age 6 to 23 months [AOR: 2.46, 95% CI: (1.49, 4.05)], Living in rural area [AOR: 2.75, 95% CI: (1.33,5.66)], absence of latrine [AOR: 4.80, 95% CI: (2.39,9.60)], absence of handwashing facility [AOR: 2.45, 95% CI: (1.53,3.93], unprotected drinking water source [AOR:2.68, 95% CI: (1.54,4.68)], and Improper waste disposal practices [AOR:3.86, 95% CI: (2.38,6.26)] were associated with diarrhea disease.ConclusionThere was a high prevalence of diarrheal disease among children in the study area. Child age, rural residence, availability of latrine and handwashing facility, source of drinking water, and improper waste disposal were notably associated with childhood diarrheal disease. Therefore, improving handwashing practices and pure water supply, proper waste disposal including the availability of latrines would minimize the burden of diarrheal disease.

Diarrhea Patterns and Climate: A Spatiotemporal Bayesian Hierarchical Analysis of Diarrheal Disease in Afghanistan.

Subject to a high burden of diarrheal diseases, Afghanistan is also susceptible to climate change. This study investigated the spatiotemporal distribution of diarrheal disease in the country and how associated it is with climate variables. Using monthly aggregated new cases of acute diarrhea reported between 2010 and 2016 and monthly averaged climate data at the district level, we fitted a hierarchical Bayesian spatiotemporal statistical model. We found aridity and mean daily temperature were positively associated with diarrhea incidence; every 1°C increase in mean daily temperature and 0.01-unit change in the aridity index were associated with a 0.70% (CI: 0.67%, 0.73%) increase and a 4.79% (CI: 4.30%, 5.26%) increase in the risk of diarrhea, respectively. Average annual temperature, on the other hand, was negatively associated, with a 3.7% (CI: 3.74%, 3.68) decrease in risk for every degree Celsius increase in annual average temperature. Temporally, most districts exhibited similar seasonal trends, with incidence peaking in summer, except for the eastern region where differences in climate patterns and population density may be associated with high rates of diarrhea throughout the year. The results from this study highlight the significant role of climate in shaping diarrheal patterns in Afghanistan, allowing policymakers to account for potential impacts of climate change in their public health assessments.

The Burden of Acute Diarrheal Disease in Young Hospitalized Urban South African Children Five Years After Rotavirus Vaccine Introduction: A Retrospective Descriptive Study.

Diarrheal disease is a leading cause of childhood morbidity and mortality worldwide. Multiple interventions, including rotavirus vaccination to infants since 2009, have reduced the incidence of diarrheal disease in South African children. Our study aimed to determine the burden of diarrheal disease 5 years after rotavirus vaccine introduction at a tertiary-level hospital. A retrospective review of a discharge summary database of children less than 5 years of age hospitalized with acute diarrheal illness from 2015 to 2016 at the Chris Hani Baragwanath Academic Hospital. Diarrheal disease accounted for 14.8% of hospital admissions. The incidence (per 100,000 population) was 675.8 (95% CI: 638.8-714.3) in 2015 and 612.2 (95% CI: 577.0-648.9) in 2016. The case fatality ratio was 2.9% over the study period. The median age at diagnosis was 12 months (interquartile range: 6.2-21.4) and 50.4% of cases occurred during infancy. One third of cases were underweight and/or stunted. In a multivariable analysis using logistic regression, the adjusted odds ratio (aOR) for death was higher in children with an associated acute lower respiratory tract infection (aOR: 3.7, 95% CI: 1.2-11.5; P = 0.021), HIV infection (aOR: 9.1, 95% CI: 2.6-31.6; P = 0.001), and an age of less than 6 months (aOR: 6.9, 95% CI: 2.1-22.9; P = 0.002). Sustained reductions in diarrheal disease incidence were observed 5 years post rotavirus vaccine implementation. In children hospitalized with an acute diarrheal illness, an increased risk of mortality occurs in young infants, children that are HIV infected, and those with an associated acute lower respiratory tract infection.

Prevalence and diversity of Cryptosporidium spp. in bamboo rats (Rhizomys sinensis) in South Central China.

Cryptosporidium is one of the most prevalent zoonotic parasites and is responsible for the high burden of diarrheal disease across the globe. Rodents are globally overpopulated and are reservoirs for a variety of zoonotic pathogens. Bamboo rats are a common species of rodent that are bred for meat and wool in China. However, the genetic characterization of Cryptosporidium in bamboo rats in China is limited. The aim of this study was to determine the occurrence and genetic characterization of Cryptosporidium in bamboo rats from South Central China. From February2017to February 2018, 435 fecal samples were collected from bamboo rats in 13 farms located in 12 cities in South Central China. All fecal specimens were examined for Cryptosporidium by PCR, and through sequencing the partial small subunit of ribosomal DNA (SSU rRNA). C. parvum-positive samples were further subtyped through analysis of the 60-kDa glycoprotein (gp60) gene sequence. Meanwhile, all the new Cryptosporidium genotypes samples were selected for further sequence characterization at the 70-kDa heat shock protein (HSP70) gene and oocyst wall protein (COWP) gene as well as gp60 gene. Infection rates of 2.1% (9/435) were recorded for Cryptosporidium. Sequence analysis confirmed the presence of two Cryptosporidium species including C. parvum (n = 2), C. occultus (n = 1) and two new Cryptosporidium genotypes termed Cryptosporidium bamboo rat genotype I (n = 5) and Cryptosporidium bamboo rat genotype II (n = 1). Two subtypes of C. parvum were identified including IIdA15G1 and IIpA19 (one each).The discovery of zoonotic Cryptosporidium species/genotypes in bamboo rats suggests they have significant zoonotic potential and pose a threat to human health. The novel sequences discovered provide new insight into genotypic variations in Cryptosporidium in bamboo rats.

Burden of laboratory-confirmed shigellosis infections in Guatemala 2007-2012: results from a population-based surveillance system

BackgroundWe describe the epidemiology and antimicrobial susceptibility patterns of culture-confirmed Shigella infections in facility-based surveillance sites in Guatemala. Current studies using quantitative molecular diagnostics suggest Shigella may contribute most to the global diarrheal disease burden. Since identification of Shigella requires culturing techniques using stool specimens and few laboratories in Guatemala routinely culture for this pathogen, little is known about the true burden of Shigella in Guatemala or, importantly, the antimicrobial resistance patterns.MethodsClinical, epidemiological, and laboratory data were collected on 5399 patients with acute diarrhea (≥3 loose stools in 24 h) from June 2007–August 2012. Multidrug resistance (MDR) was defined as resistance to ampicillin and trimethoprim/sulfamethoxazole.ResultsFive percent (261) of stool specimens yielded Shigella spp. The annual incidence of laboratory-confirmed infections ranged from 5.0 to 24.1 per 100,000 persons in Santa Rosa and 0.3 to 6.2 per 100,000 in Quetzaltenango; 58% of cases occurred in children < 5 years of age. Thirty patients were hospitalized; one patient died. Oral rehydration or intravenous solution was used to treat 72% of hospitalized and 15% of ambulatory cases. Fifty-nine percent of cases were S. flexneri and 51% of cases were MDR.ConclusionsShigella is an important cause of bacterial diarrhea in children and prevalence of MDR highlights the importance of appropriate treatment regimens. This study demonstrates that strengthening laboratory capacity in Guatemala can help determine causes which can lead to prevention of diarrheal diseases, particularly in children. Such capacity building is also critical for rapid detection and control of public health threats at their source and therefore for global health security.

Selecting Household Water Treatment Options on the Basis of World Health Organization Performance Testing Protocols.

The World Health Organization's International Scheme to Evaluate Household Water Treatment Technologies serves to benchmark microbiological performance of existing and novel technologies and processes for small-scale drinking water treatment according to a tiered system. There is widespread uncertainty around which tiers of performance are most appropriate for technology selection and recommendation in humanitarian response or for routine safe water programming. We used quantitative microbial risk assessment (QMRA) to evaluate attributable reductions in diarrheal disease burden associated with water treatment technologies meeting the three tiers of performance under this Scheme, across a range of conditions. According to mean estimates and under most modeling conditions, potential health gains attributable to microbiologically improved drinking water are realized at the middle tier of performance: "comprehensive protection: high pathogen removal (★★)" for each reference pathogen. The highest tier of performance may yield additional marginal health gains where untreated water is especially contaminated and where adherence is 100%. Our results highlight that health gains from improved efficacy of household water treatment technology remain marginal when adherence is less than 90%. While selection of water treatment technologies that meet minimum WHO efficacy recommendations for comprehensive protection against waterborne pathogens is critical, additional criteria for technology choice and recommendation should focus on potential for correct, consistent, and sustained use.

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.

Escherichia coli isolated from food sources and irrigation water: A potential risk for causing intestinal dysfunction?

We have previously shown that diarrheagenic Escherichia coli (DEC) and non-DEC are prevalent in food sources and irrigation water in South Africa. Recent data suggest that an increased relative abundance of faecal Enterobacteriaceae is associated with poorer health outcomes among children in developing countries. Thus, exposure to non-DEC from environmental sources may incur adverse effects, although the mechanisms underlying these effects remain obscure. To further elucidate this phenomenon, we assayed non-DEC strains from environmental sources in South Africa for phenotypes that may be associated with intestinal dysfunction (ID). DEC strains were also used. The strains had previously been isolated from Producer Distributor Bulk Milk (PDBM), irrigated lettuce, street vendor coleslaw and irrigation water.In-vitro assays identified; biofilm formation (n = 38), extracellular polymeric substance (EPS) formation (n = 38), cytotoxic activity (n = 10), disruption of tight junctions and induction of Interleukin 8 (IL-8) on polarized T-84 cells (n = 20). The number of strains tested for each assay differed, depending on prior molecular and phenotypic characterization that signalled potential pathogenicity in-vitro. Subsequently, all strains having data points for all analyses were used to compute Principal Component Analysis (PCA) plot curves to infer potential associations amongst test strains and a standard DEC pathogenic strain (042).Biofilm formation on glass coverslips after strains were grown in nutrient-rich media (LB and DMEM-F12 + 0.5% D-Mannose) at 37 °C varied based on pathotype (DEC and non-DEC) and source of isolation (food, irrigation water, clinical) suggesting that pathotype and source isolation influence persistence within a defined environmental niche. Additionally, DEC isolated from irrigated lettuce had a significantly higher (p ≤ 0.05) propensity for biofilm formation in both media compared to all strains including DEC standard controls. This suggested the propensity for irrigated lettuce as a potential source of persistent pathogenic strains. Furthermore, all strains were able to form EPS suggesting the ability to form mature biofilms under conditions relevant for food processing (20–25 °C). Of the (60%, 6 out of 10) strains that showed cytotoxic activity, most (83%, 5 out of 6 strains) were non-DEC isolated from food sources many of which are consumed with minimal processing.Mean percentage reduction in initial TEER (a measure of intestinal disruption), did not significantly differ (p = 0.05) in all test strains from that observed in the standard DEC. Additionally, IL-8 induction from strains isolated from PDBM (139 pg/mL), irrigation water (231.93 pg/mL) and irrigated lettuce (152.98 pg/mL) was significantly higher (p ≤ 0.05) than in the commensal strain aafa. PCA categorized strains based on sources of isolation showed potential for use in source tracking especially when comparing many strains from various environmental sources. We show that non-DEC strains along the food chain possess characteristics that may lead to ID. Further investigations using a larger collection of strains may provide a clearer link to these reported observations that could be associated with the high diarrheal disease burden within the country, especially among infants.

Capturing the true burden of Shigella and ETEC: The way forward

The mortality and morbidity burden estimation of diarrheal diseases (DD), and Shigella and Enterotoxigenic E. Coli (ETEC) varies among different studies and by the models used for producing these estimates. Understanding the real burden of these important pathogens will guide public health and policy makers to prioritize resources for accelerating interventions against these enteric infections. In addition, long term effects, in the form of growth faltering, cognitive impairment and decreased school performance are important aspects of burden that has not been well captured. Efforts to incorporate these effects and refine their estimation, in the form of Disability Adjusted Life years (DALYs) are very important to inform the burden of diarrheal diseases and Shigella and ETEC specifically. The Institute for Health Metrics and Evaluation (IHME) at the University of Washington conducted a workshop at the VASE 2018 meeting to discuss IHME Global Burden of Diseases (GBD) modelling methods for diarrheal diseases, with a focus on ETEC and Shigella estimates in relation to other pathogens, including limitations, areas of improvements, and IHME plans for future GBD iterations.

Bacterial Contamination on Latrine Surfaces in Community and Household Latrines in Kathmandu, Nepal.

A lack of sanitation infrastructure is a major contributor to the global burden of diarrheal disease, particularly in low-income countries. Access to basic sanitation was identified as part of the 2015 United Nations Sustainable Development Goals. However, current definitions of “basic” sanitation infrastructure exclude community or shared sanitation, due to concerns around safety, equity, and cleanliness. The purpose of this study was to measure and compare bacterial contamination on community and household latrine surfaces in Kathmandu, Nepal. One hundred and nineteen swab samples were collected from two community and five household latrines sites. Community latrine samples were taken before and after daily cleaning, while household samples were collected at midday, to reflect normal conditions. Concentrations of total coliforms and Escherichia coli were measured using membrane filtration methods. Results found almost no differences between bacterial contamination on latrine surfaces in community and household latrines, with the exception of latrine slabs/seats that were more contaminated in the community latrines under dirty conditions. The study also identified surfaces with higher levels of contamination. Findings demonstrated that well-maintained community latrines may be as clean, or cleaner, than household latrines and support the use of community latrines for improving access to sanitation infrastructure in a low-income country setting.

Functional Prediction of Hypothetical Proteins from Shigella flexneri and Validation of the Predicted Models by Using ROC Curve Analysis.

Shigella spp. constitutes some of the key pathogens responsible for the global burden of diarrhoeal disease. With over 164 million reported cases per annum, shigellosis accounts for 1.1 million deaths each year. Majority of these cases occur among the children of the developing nations and the emergence of multi-drug resistance Shigella strains in clinical isolates demands the development of better/new drugs against this pathogen. The genome of Shigella flexneri was extensively analyzed and found 4,362 proteins among which the functions of 674 proteins, termed as hypothetical proteins (HPs) had not been previously elucidated. Amino acid sequences of all these 674 HPs were studied and the functions of a total of 39 HPs have been assigned with high level of confidence. Here we have utilized a combination of the latest versions of databases to assign the precise function of HPs for which no experimental information is available. These HPs were found to belong to various classes of proteins such as enzymes, binding proteins, signal transducers, lipoprotein, transporters, virulence and other proteins. Evaluation of the performance of the various computational tools conducted using receiver operating characteristic curve analysis and a resoundingly high average accuracy of 93.6% were obtained. Our comprehensive analysis will help to gain greater understanding for the development of many novel potential therapeutic interventions to defeat Shigella infection.