A polyvalent multiepitope protein cross-protects against Vibrio cholerae infection in rabbit colonization and passive protection models.

Using epitope- and structure-based multiepitope fusion antigen vaccinology platform, we constructed a polyvalent protein immunogen that presents antigenic domains (epitopes) of Vibrio cholerae toxin-coregulated pilus A, cholera toxin (CT), sialidase, hemolysin A, flagellins (B, C, and D), and peptides mimicking lipopolysaccharide O-antigen on a flagellin B backbone. Mice and rabbits immunized intramuscularly with this polyvalent protein immunogen developed antibodies to all of the virulence factors targeted by the immunogen except lipopolysaccharide. Mouse and rabbit antibodies exhibited functional activities against CT enterotoxicity, CT binding to GM1 ganglioside, bacterial motility, and in vitro adherence of V. cholerae O1, O139, and non-O1/non-O139 serogroup strains. When challenged orogastrically with V. cholerae O1 El Tor N16961 or a non-O1/non-O139 strain, rabbits IM immunized with the immunogen showed a 2-log (99%) reduction in V. cholerae colonization of small intestines. Moreover, infant rabbits born to the mother immunized with the protein immunogen acquired antibodies passively and were protected from bacterial intestinal colonization (>2-log reduction), severe diarrhea (100%), and mild diarrhea (88%) after infection with V. cholerae O1 El Tor (N16961), O1 classical (O395), O139 (Bengal), or a non-O1/non-O139 strain. This study demonstrated that this polyvalent cholera protein is broadly immunogenic and cross-protective, and an adult rabbit colonization model and an infant rabbit passive protection model fill a gap in preclinical efficacy assessment in cholera vaccine development.

Evaluation of a rapid diagnostic test for detection of Vibrio cholerae O1 in the Democratic Republic of the Congo: Preventative intervention for cholera for 7 days (PICHA7 program).

OBJECTIVE: Globally, there are estimated to be 2.9 million cholera cases annually. Early detection of cholera outbreaks is crucial for resource allocation for case management and for targeted interventions to be delivered to stop the spread of cholera. In resource limited settings such as Eastern Democratic Republic of the Congo (DRC), there is often limited laboratory capacity for analysing stool samples for cholera by bacterial culture. Therefore, rapid diagnostic tests (RDTs) for cholera present a promising tool to rapidly test stool samples in a health facility setting for cholera. Our objective is to evaluate the Crystal VC O1 RDT for cholera detection compared with bacterial culture and polymerase chain reaction (PCR) for Vibrio cholerae. METHODS: From March 2020 to December 2022, stool samples were collected from 644 diarrhoea patients admitted to 94 health facilities in Bukavu in Eastern DRC. Patient stool samples were analysed by Crystal VC O1 RDT for cholera and by bacterial culture and PCR for V. cholerae O1. RESULTS: Twenty six percent of diarrhoea patients (166/644) had stool samples positive for cholera by RDT, and 24% (152/644) had stool samples positive for V. cholerae O1 by bacterial culture or PCR. The overall specificity and sensitivity of the Crystal VC O1 RDT by direct testing was 94% (95% confidence interval [CI]: 92%-96%) and 90% (95% CI, 84%-94%), respectively, when compared with either a positive result by bacterial culture or PCR. CONCLUSION: Our findings suggest that the Crystal VC O1 RDT presents a promising tool for cholera surveillance in this cholera endemic setting in sub-Saharan Africa.

A broadly immunogenic polyvalent Shigella multiepitope fusion antigen protein protects against Shigella sonnei and Shigella flexneri lethal pulmonary challenges in mice.

There are no licensed vaccines for Shigella, a leading cause of children's diarrhea and a common etiology of travelers' diarrhea. To develop a cross-protective Shigella vaccine, in this study, we constructed a polyvalent protein immunogen to present conserved immunodominant epitopes of Shigella invasion plasmid antigens B (IpaB) and D (IpaD), VirG, GuaB, and Shiga toxins on backbone protein IpaD, by applying an epitope- and structure-based multiepitope-fusion-antigen (MEFA) vaccinology platform, examined protein (Shigella MEFA) broad immunogenicity, and evaluated antibody function against Shigella invasion and Shiga toxin cytotoxicity but also protection against Shigella lethal challenge. Mice intramuscularly immunized with Shigella MEFA protein developed IgG responses to IpaB, IpaD, VirG, GuaB, and Shiga toxins 1 and 2; mouse sera significantly reduced invasion of Shigella sonnei, Shigella flexneri serotype 2a, 3a, or 6, Shigella boydii, and Shigella dysenteriae type 1 and neutralized cytotoxicity of Shiga toxins of Shigella and Shiga toxin-producing Escherichia coli in vitro. Moreover, mice intranasally immunized with Shigella MEFA protein (adjuvanted with dmLT) developed antigen-specific serum IgG, lung IgG and IgA, and fecal IgA antibodies, and survived from lethal pulmonary challenge with S. sonnei or S. flexneri serotype 2a, 3a, or 6. In contrast, the control mice died, became unresponsive, or lost 20% of body weight in 48 h. These results indicated that this Shigella MEFA protein is broadly immunogenic, induces broadly functional antibodies, and cross-protects against lethal pulmonary challenges with S. sonnei or S. flexneri serotypes, suggesting a potential application of this polyvalent MEFA protein in Shigella vaccine development.

Intradermally Administered Enterotoxigenic Escherichia coli Vaccine Candidate MecVax Induces Functional Serum Immunoglobulin G Antibodies against Seven Adhesins (CFA/I and CS1 through CS6) and Both Toxins (STa and LT).

There are no vaccines licensed for enterotoxigenic Escherichia coli (ETEC), a leading bacterial cause of children's diarrhea and travelers' diarrhea. MecVax, a multivalent E. coli vaccine candidate composed of two epitope- and structure-based polyvalent proteins (toxoid fusion 3xSTaN12S-mnLTR192G/L211A and colonization factor antigen [CFA]/I/II/IV multiepitope fusion antigen [MEFA]), is designed to induce broad antiadhesin and antitoxin antibodies against heterogeneous ETEC pathovars. When administered intraperitoneally or intramuscularly, MecVax was shown to induce antibodies against seven ETEC adhesins (CFA/I and CS1 to CS6) produced by ETEC pathovars that cause over 60% of ETEC-associated diarrheal cases and moderate-to-severe cases and both toxins (heat-labile toxin [LT] and heat-stable toxin [STa]) expressed by all ETEC strains. To further characterize the immunogenicity of this protein-based injectable subunit vaccine candidate and to explore other parenteral administration routes for the product, in this study we immunized mice intradermally (i.d.) with MecVax and measured antigen-specific antibody responses and further antibody functional activities against the adhesins and toxins targeted by the vaccine. Data showed that mice immunized i.d. with MecVax developed robust anti-CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, LT and anti-STa IgG responses. Furthermore, antibodies derived from MecVax administered via the i.d. route inhibited the adherence of ETEC or E. coli strains expressing any of the seven target adhesins (CFA/I and CS1 to CS6) and neutralized the enterotoxicity of LT and STa. These results confirmed broad immunogenicity of MecVax and suggested that this multivalent ETEC subunit vaccine candidate can be effectively delivered via the i.d. route. IMPORTANCE ETEC is a leading bacterial cause of diarrhea in children living in developing countries and international travelers. Developing an effective vaccine for ETEC diarrhea has been hampered because of the challenges of virulence heterogeneity and the difficulties of inducing neutralizing antibodies against the key toxin STa. MecVax, a subunit vaccine candidate carrying two polyvalent protein antigens, for the first time induces functional antibodies against the most important ETEC adhesins, which are associated with a majority of diarrheal cases and moderate-to-severe cases, and also against the enterotoxicity of LT and more importantly STa, which plays a key role in children's diarrhea and travelers' diarrhea, potentially leading to the development of a truly effective ETEC vaccine. Data from this study may also indicate that this ETEC subunit vaccine can be administered effectively via the i.d. route, expanding clinical administration options for this vaccine product.

The Controlled Human Infection Model for Enterotoxigenic Escherichia coli.

The controlled human infection model (CHIM) for enterotoxigenic Escherichia coli (ETEC) has been instrumental in defining ETEC as a causative agent of acute watery diarrhea, providing insights into disease pathogenesis and resistance to illness, and enabling preliminary efficacy evaluations for numerous products including vaccines, immunoprophylactics, and drugs. Over a dozen strains have been evaluated to date, with a spectrum of clinical signs and symptoms that appear to replicate the clinical illness seen with naturally occurring ETEC. Recent advancements in the ETEC CHIM have enhanced the characterization of clinical, immunological, and microbiological outcomes. It is anticipated that omics-based technologies applied to ETEC CHIMs will continue to broaden our understanding of host-pathogen interactions and facilitate the development of primary and secondary prevention strategies.

An innovative approach in monitoring oral cholera vaccination campaign: integration of a between-round survey.

BACKGROUND: Monitoring and Evaluation (M&E) is essential in ensuring population's access to immunization. Surveys are part of this M&E approach but its timing limits the use of its results to improve the coverage of the evaluated campaign. An oral cholera vaccination campaign was organized in a health district of the Far North region of Cameroon and involved an innovative M&E approach. The aim of this project was to assess the feasibility and effect of using recommendations of a community-based immunization and communication coverage survey conducted after the first round of an OCV campaign on the coverage of the second-round of the campaign. METHODS: Two community-based surveys were included in the M&E plan and conducted at the end of each of the campaign rounds. Data were collected by trained and closely supervised surveyors and reported using smartphones. Key results of the first-round survey were disseminated to campaign implementing team prior to the second round. The two rounds of the pre-emptive campaign were organized by the Cameroon Ministry of Public Health and partners with a two-week interval in the Mogode Health District of the Far North region of Cameroon in May and June 2017. RESULTS: Of 120 targeted clusters, 119 (99.1%) and 117 (97.5%) were reached for the first and second rounds respectively. Among the Mogode population eligible for vaccination, the immunization coverage based on evidence (card or finger mark) were estimated at 81.0% in the first round and increased to 88.8% in the second round (X2=69.0 and p <0.00). For the second round, we estimated 80.1% and 4.3% of persons who were administered 2 doses and 1 dose of OCV with evidence respectively, and 3.8% of persons who have not been vaccinated. The distribution of campaign communication coverage per health area was shared with the campaign coordination team for better planning of the second round campaign activities. CONCLUSIONS: It is feasible to plan and implement coverage survey after first round OCV campaign and use its results for the better planning of the second round. For the present study, this is associated to the improvement of OCV coverage in the second-round vaccination. If this is persistent in other contexts, it may apply to improve coverage of any health campaign that is organized in more than one round.

Contrasting Epidemiology of Cholera in Bangladesh and Africa.

In Bangladesh and West Bengal cholera is seasonal, transmission occurs consistently annually. By contrast, in most African countries, cholera has inconsistent seasonal patterns and long periods without obvious transmission. Transmission patterns in Africa occur during intermittent outbreaks followed by elimination of that genetic lineage. Later another outbreak may occur because of reintroduction of new or evolved lineages from adjacent areas, often by human travelers. These then subsequently undergo subsequent elimination. The frequent elimination and reintroduction has several implications when planning for cholera's elimination including: a) reconsidering concepts of definition of elimination, b) stress on rapid detection and response to outbreaks, c) more effective use of oral cholera vaccine and WASH, d) need to readjust estimates of disease burden for Africa, e) re-examination of water as a reservoir for maintaining endemicity in Africa. This paper reviews major features of cholera's epidemiology in African countries which appear different from the Ganges Delta.

Preclinical Characterization of Immunogenicity and Efficacy against Diarrhea from MecVax, a Multivalent Enterotoxigenic E. coli Vaccine Candidate.

There are no vaccines licensed for enterotoxigenic Escherichia coli (ETEC), a leading cause of diarrhea for children in developing countries and international travelers. Virulence heterogeneity among strains and difficulties identifying safe antigens for protective antibodies against STa, a potent but poorly immunogenic heat-stable toxin which plays a key role in ETEC diarrhea, are challenges in ETEC vaccine development. To overcome these challenges, we applied a toxoid fusion strategy and a novel epitope- and structure-based multiepitope fusion antigen (MEFA) vaccinology platform to construct two chimeric multivalent proteins, toxoid fusion 3xSTaN12S-mnLTR192G/L211A and adhesin CFA/I/II/IV MEFA, and demonstrated that the proteins induced protective antibodies against STa and heat-labile toxin (LT) produced by all ETEC strains or the seven most important ETEC adhesins (CFA/I and CS1 to CS6) expressed by the ETEC strains causing 60 to 70% of diarrheal cases and moderate to severe cases. Combining two proteins, we prepared a protein-based multivalent ETEC vaccine, MecVax. MecVax was broadly immunogenic; mice and pigs intramuscularly immunized with MecVax developed no apparent adverse effects but had robust antibody responses to the target toxins and adhesins. Importantly, MecVax-induced antibodies were broadly protective, demonstrated by significant adherence inhibition against E. coli bacteria producing any of the seven adhesins and neutralization of STa and cholera toxin (CT) enterotoxicity. Moreover, MecVax protected against watery diarrhea and provided over 70% and 90% protection against any diarrhea from an STa-positive or an LT-positive ETEC strain in a pig challenge model. These results indicated that MecVax induces broadly protective antibodies and prevents diarrhea preclinically, signifying that MecVax is potentially an effective injectable vaccine for ETEC. IMPORTANCE Enterotoxigenic Escherichia coli (ETEC) bacteria are a top cause of children's diarrhea and travelers' diarrhea and are responsible for over 220 million diarrheal cases and more than 100,000 deaths annually. A safe and effective ETEC vaccine can significantly improve public health, particularly in developing countries. Data from this preclinical study showed that MecVax induces broadly protective antiadhesin and antitoxin antibodies, becoming the first ETEC vaccine candidate to induce protective antibodies inhibiting adherence of the seven most important ETEC adhesins and neutralizing the enterotoxicity of not only LT but also STa toxin. More importantly, MecVax is shown to protect against clinical diarrhea from STa-positive or LT-positive ETEC infection in a pig challenge model, recording protection from antibodies induced by the protein-based, injectable, subunit vaccine MecVax against ETEC diarrhea and perhaps the possibility of intramuscularly administered protein vaccines for protection against intestinal mucosal infection.

Effects of a Water, Sanitation, and Hygiene Mobile Health Program on Diarrhea and Child Growth in Bangladesh: A Cluster-randomized Controlled Trial of the Cholera Hospital-based Intervention for 7 Days (CHoBI7) Mobile Health Program.

BACKGROUND: The Cholera Hospital-Based Intervention for 7 Days (CHoBI7) mobile health (mHealth) program was a cluster-randomized controlled trial of diarrhea patient households conducted in Dhaka, Bangladesh. METHODS: Patients were block-randomized to 3 arms: standard message on oral rehydration solution use; health facility delivery of CHoBI7 plus mHealth (no home visits); and health facility delivery of CHoBI7 plus 2 home visits and mHealth. The primary outcome was reported diarrhea in the past 2 weeks collected monthly for 12 months. The secondary outcomes were stunting, underweight, and wasting at a 12-month follow-up. Analysis was intention-to-treat. RESULTS: Between 4 December 2016 and 26 April 2018, 2626 participants in 769 households were randomly allocated to 3 arms: 849 participants to the standard message arm, 886 to mHealth with no home visits arm, and 891 to the mHealth with 2 home visits. Children <5 years had significantly lower 12-month diarrhea prevalence in both the mHealth with 2 home visits arm (prevalence ratio [PR]: 0.73 [95% confidence interval {CI}, .61-.87]) and the mHealth with no home visits arm (PR: 0.82 [95% CI, .69-.97]). Children <2 years were significantly less likely to be stunted in both the mHealth with 2 home visits arm (33% vs 45%; odds ratio [OR]: 0.55 [95% CI, .31-.97]) and the mHealth with no home visits arm (32% vs 45%; OR: 0.54 [95% CI, .31-.96]) compared with children in the standard message arm. CONCLUSIONS: The CHoBI7 mHealth program lowered pediatric diarrhea and stunting among diarrhea patient households. CLINICAL TRIALS REGISTRATION: NCT04008134.

Characterization of Enteric Disease in Children by Use of a Low-Cost Specimen Preservation Method.

Diarrhea is a leading cause of death in children under five. Molecular methods exist for the rapid detection of enteric pathogens; however, the logistical costs of storing stool specimens limit applicability. We sought to demonstrate that dried specimens preserved using filter paper can be used to identify diarrheal diseases causing significant morbidity among children in resource-constrained countries. A substudy was nested into cholera surveillance in Cameroon. Enrollment criteria included enrollment between 1 August 2016 and 1 October 2018, age of <18 years, availability of a stool specimen, and having three or more loose stools within 24 h with the presence of dehydration and/or blood. A total of 7,227 persons were enrolled, of whom 2,746 met enrollment criteria and 337 were included in this analysis using the enteric TaqMan array card. Bacterial pathogens were compared to severity of diarrhea, age, and sex, among other variables. One hundred seven were positive for enterotoxigenic Escherichia coli, of which 40.2% (n = 43) had heat-labile enterotoxin (LT) and the heat-stable enterotoxin STh, 19.6% (n = 21) had LT and the heat-stable enterotoxin STp, and 49.5% (n = 53) had LT only. Major colonization factors (CFs) were present in 43.9% of enterotoxigenic E. coli (ETEC)-positive patients. Ninety-six were positive for Shigella, of whom 14 (14.6%) reported dysentery. Model-derived quantitative cutoffs identified 116 (34.4%) with one highly diarrhea-associated pathogen and 16 (4.7%) with two or more. Shigella and rotavirus were most strongly associated with diarrhea in children with mixed infections. Dried-filter-paper-preserved specimens eliminate the need for frozen stool specimens and will facilitate enteric surveillance and contribute to the understanding of disease burden, which is needed to guide vaccine development and introduction. This study confirms rotavirus, Shigella, and ETEC as major contributors to pediatric diarrheal disease in two regions of Cameroon.

Three transmission events of Vibrio cholerae O1 into Lusaka, Zambia.

BACKGROUND: Cholera has been present and recurring in Zambia since 1977. However, there is a paucity of data on genetic relatedness and diversity of the Vibrio cholerae isolates responsible for these outbreaks. Understanding whether the outbreaks are seeded from existing local isolates or if the outbreaks represent separate transmission events can inform public health decisions. RESULTS: Seventy-two V. cholerae isolates from outbreaks in 2009/2010, 2016, and 2017/2018 in Zambia were characterized using multilocus variable number tandem repeat analysis (MLVA) and whole genome sequencing (WGS). The isolates had eight distinct MLVA genotypes that clustered into three MLVA clonal complexes (CCs). Each CC contained isolates from only one outbreak. The results from WGS revealed both clustered and dispersed single nucleotide variants. The genetic relatedness of isolates based on WGS was consistent with the MLVA, each CC was a distinct genetic lineage and had nearest neighbors from other East African countries. In Lusaka, isolates from the same outbreak were more closely related to themselves and isolates from other countries than to isolates from other outbreaks in other years. CONCLUSIONS: Our observations are consistent with i) the presence of random mutation and alternative mechanisms of nucleotide variation, and ii) three separate transmission events of V. cholerae into Lusaka, Zambia. We suggest that locally, case-area targeted invention strategies and regionally, well-coordinated plans be in place to effectively control future cholera outbreaks.

Prospective cohort study of child mouthing of faeces and fomites in Dhaka, Bangladesh (CHoBI7 Program).

OBJECTIVE: To characterise childhood mouthing and handling behaviours and to assess the association between hand-to-object and object-to-mouth contacts and diarrhoea prevalence in young children in urban Dhaka, Bangladesh. METHODS: A prospective cohort study was conducted among 494 children under 5 years of age in Dhaka, Bangladesh. This study was nested within the randomised controlled trial of the Cholera Hospital-Based Intervention for 7 Days (CHoBI7) mobile health (mHealth) program. The CHoBI7 mHealth program focuses on promoting handwashing with soap and water treatment to diarrhoea patients and their household members through mobile messages and a single in person visit. Mouthing and handling of faeces and fomites among young children was measured by five-hour structured observation and caregiver reports. Diarrhoea surveillance data was collected monthly for 12 months. RESULTS: Fifty five percent of caregivers reported that their child put a visibly dirty fomite (object or soil) in their mouth in the past week. Caregivers reported that 50% of children had mouthed visibly dirty objects, 26% had mouthed dirt, and 2% had mouthed faeces. Forty five percent of children were observed mouthing a visibly dirty fomite during structured observation, 40% of children were observed mouthing a visibly dirty object, 10% were observed mouthing soil, and one child (0.2%) was observed mouthing faeces. Mouthing of visibly dirty fomites was highest for children 12-18 months of age with 69% of these children having caregiver reports and 54% having observed events. Children with caregiver reports of mouthing faeces had a significantly higher odds of diarrhoea over the subsequent month (Odds Ratio: 4.54; 95% Confidence Interval: 1.06, 19.48). CONCLUSION: These findings demonstrate that mouthing of contaminated fomites among young children is frequent in urban environments in Bangladesh, and that mouthing faeces is associated with a significantly higher odds of diarrhoea. Interventions are urgently needed to protect young children from faecal pathogens in their play spaces.

OBJECTIF: Caractériser les comportements de mâchouillement et de manipulation par les enfants et évaluer l'association entre les contacts main-objet et objet-bouche et la prévalence de la diarrhée chez les jeunes enfants dans la ville de Dhaka, au Bangladesh. MÉTHODES: Une étude de cohorte prospective a été menée auprès de 494 enfants de moins de 5 ans à Dhaka, au Bangladesh. Cette étude s'inscrivait dans le cadre de l'essai contrôlé randomisé du programme CHoBI7 (Cholera-Hospital-Based-Intervention-for-7-days) de santé mobile (mHealth. Le programme de santé mobile CHoBI7 se concentre sur la promotion du traitement de l'eau et du lavage des mains avec à l'eau et au savon aux patients atteints de diarrhée et aux membres de leur foyer par le biais de messages mobiles et de visites de face à face. Le mâchouillement et la manipulation des excréments et des fomites chez les jeunes enfants ont été mesurés par des observations structurées de cinq heures et par les rapports des personnes s'occupant d'enfants (soignants). Les données de surveillance de la diarrhée ont été recueillies chaque mois pendant 12 mois. RÉSULTATS: 55% des soignants ont déclaré que leur enfant avait mis un fomite visiblement sale (objet ou terre) dans sa bouche au cours de la semaine précédente. Les soignants ont indiqué que 50% des enfants avaient mâchouillé des objets visiblement sales, 26% avaient mâchouillé de la terre et 2% avaient mâchouillé des excréments. 45% des enfants ont été observés en train de mâchouiller un fomite visiblement sale au cours d'une observation structurée. 40% des enfants ont été observés en train de mâchouiller un objet, 10% ont été observés en train de mâchouiller de la terre et un enfant (0,2%) a été observé en train de mâchouiller des excréments. Le mâchouillement de fomites visiblement sales était le plus fréquent chez les enfants de 12 à 18 mois; 69% de ces enfants ont été signalés par les soignants et 54% ont été observés en train de le faire. Les enfants dont les soignants avaient signalé un mâchouillement d'excréments présentaient un risque de diarrhée nettement plus élevé au cours du mois suivant (rapport de cotes: 4,54; intervalle de confiance à 95%: 1,06-19,48). CONCLUSION: Ces résultats démontrent que le fait de mâchouiller des fomites contaminés chez les jeunes enfants est fréquent en milieu urbain au Bangladesh et que le fait de mâchouiller des excréments est associé à un risque de diarrhée nettement plus élevé. Des interventions sont urgemment nécessaires pour protéger les jeunes enfants des agents pathogènes fécaux dans leurs espaces de jeu.

Process evaluation for the delivery of a water, sanitation and hygiene mobile health program: findings from the randomised controlled trial of the CHoBI7 mobile health program.

OBJECTIVE: The Cholera-Hospital-Based Intervention for 7-days (CHoBI7) mobile health (mHealth) program delivers mobile messages to diarrhoea patient households promoting water treatment and handwashing with soap. The randomised controlled trial (RCT) of the CHoBI7 mHealth program demonstrated this intervention was effective in significantly reducing diarrhoea and stunting amoung young children. The objective of this study was to assess the implementation of the CHoBI7 mHealth program in delivering mHealth messages during this RCT. METHODS: 517 diarrhoea patient households with 1777 participants received weekly text, voice and interactive voice response (IVR) messages from the CHoBI7 mHealth program over the 12-month program period. The program process evaluation indicators were the following: the percentage of CHoBI7 mHealth messages received and fully listened to by program households (program fidelity and dose), and household members reporting receiving and sharing an mHealth message from the program in the past two weeks (program reach). RESULTS: Ninety two percent of text messages were received by program households. Eighty three percent of voice and 86% of IVR messages sent were fully listened to by at least one household member. Eighty one percent of IVR quiz responses from households were answered correctly. Program households reported receiving a CHoBI7 mHealth message in the past two weeks at 79% of monthly household visits during the 12-month program. Seventy seven percent of participants reported sharing a program message with a spouse, 55% with a neighbour and 49% with a child during the program period. CONCLUSION: There was high fidelity, dose and reach of mobile messages delivered for the CHoBI7 mHealth program. This study presents an approach for process evaluation that can be implemented to evaluate future mHealth programs.

OBJECTIF: Le programme CHoBI7 (Cholera-Hospital-Based-Intervention-for-7-days) de santé mobile (mHealth) délivre des messages mobiles aux ménages avec patients atteints de diarrhée pour promouvoir le traitement de l'eau et le lavage des mains au savon. L'essai contrôlé randomisé (ECR) du programme mHealth CHoBI7 a démontré que cette intervention était efficace pour réduire de manière significative la diarrhée et le retard de croissance chez les jeunes enfants. L'objectif de cette étude était d'évaluer la mise en œuvre du programme CHoBI7 mHealth dans la diffusion des messages mHealth au cours de cet ECR. MÉTHODES: 517 ménages avec des patients atteints de diarrhée ont reçu chaque semaine des messages SMS, vocaux et de réponse vocale interactive (RVI) du programme mHealth de CHoBI7 pendant les 12 mois du programme. Les indicateurs d'évaluation du processus du programme étaient les suivants: le pourcentage de messages mHealth du programme CHoBI7 reçus (fidélité au programme et dose) et entièrement écoutés par les ménages participant au programme (fidélité au programme et dose) et les bénéficiaires déclarant avoir reçu et partagé un message mHealth du programme (portée du programme) au cours des deux dernières semaines. RÉSULTATS: 92% des SMS ont été reçus par les ménages participant au programme. 83% des messages vocaux et 86% des messages RVI envoyés ont été entièrement écoutés par au moins un membre du ménage. 81% des réponses aux quiz RVI des ménages ont été correctement répondues. Les ménages du programme ont déclaré avoir reçu un message CHoBI7 mHealth au cours des deux dernières semaines dans 79% des visites mensuelles des ménages pendant les 12 mois du programme. 77% des participants ont déclaré avoir partagé un message du programme avec un conjoint, 55% avec un voisin et 49% avec un enfant pendant la durée du programme. CONCLUSION: La dose et les messages délivrés dans le cadre du programme mHealth de CHoBI7 l'ont été avec une fidélité élevée. Cette étude présente une approche d'évaluation des processus qui peut être mise en œuvre pour évaluer les futurs programmes mHealth.

Child mouthing of soil and presence of animals in child sleeping spaces are associated with growth faltering among young children in Dhaka, Bangladesh (CHoBI7 Program).

OBJECTIVE: The objective of the study was to investigate potential risk factors for growth faltering among children under 5 years of age. METHOD: We conducted a prospective cohort study of 553 children under 5 years from diarrhoea patient households in urban Dhaka, Bangladesh. Height and weight measurements were obtained at baseline and at a 12-month follow-up. Caregivers of young children were administered a monthly questionnaire on household sociodemographic characteristics and hygiene practices. RESULTS: Children with caregiver reports of mouthing soil at the majority of household visits had a significant reduction in their height-for-age z-scores (HAZ) from baseline to the 12-month follow-up (ΔHAZ: -0.28 (95% confidence interval (CI): -0.51, -0.05)). A significant reduction in HAZ was also observed for children in households with animals in their sleeping space (ΔHAZ: -0.37 (95% CI: -0.71, -0.04)). CONCLUSION: These findings provide further evidence to support the hypothesis that child mouthing of soil and the presence of animals in the child's sleeping space are potential risk factors for growth faltering among young children. Interventions are urgently needed to provide clean play and sleeping spaces for young children to reduce exposure to faecal pathogens through child mouthing.

OBJECTIF: L'objectif de l'étude était d'examiner les facteurs de risque potentiels de retard de croissance chez les enfants de moins de 5 ans. MÉTHODE: Nous avons mené une étude de cohorte prospective sur 553 enfants de moins de 5 ans provenant de ménages avec des patients diarrhéiques dans la ville de Dhaka, au Bangladesh. Les mesures de taille et de poids ont été obtenues au départ et à 12 mois de suivi. Les personnes s'occupant de jeunes enfants (les gardiens) ont reçu un questionnaire mensuel sur les caractéristiques sociodémographiques des ménages et les pratiques d'hygiène. RÉSULTATS: Les enfants pour lesquels les gardiens ont déclaré qu'ils mâchouillaient de la terre lors de la majorité des visites à domicile présentaient une diminution du score Z de taille pour l'âge (TAZ) de manière significative de l'âge de référence au 12 mois de suivi (ΔTAZ −0,28 (intervalle de confiance (IC) à 95%: −0,51, −0,05)). Une réduction significative des TAZ a également été observée pour les enfants des ménages ayant des animaux dans leur espace de couchage (ΔTAZ −0,37 (IC95%: −0,71, −0,04)). CONCLUSION: Ces résultats apportent des données supplémentaires pour appuyer l'hypothèse selon laquelle le fait que l'enfant mâchouille de la terre et la présence d'animaux dans son espace de couchage sont des facteurs de risque potentiels de retard de croissance chez les jeunes enfants. Des interventions sont urgemment nécessaires pour fournir des espaces de jeu et de sommeil sains aux jeunes enfants afin de réduire l'exposition aux agents pathogènes fécaux par le mâchouillement des enfants.

The quality of drinking and domestic water from the surface water sources (lakes, rivers, irrigation canals and ponds) and springs in cholera prone communities of Uganda: an analysis of vital physicochemical parameters.

BACKGROUND: Water is the most abundant resource on earth, however water scarcity affects more than 40% of people worldwide. Access to safe drinking water is a basic human right and is a United Nations Sustainable Development Goal (SDG) 6. Globally, waterborne diseases such as cholera are responsible for over two million deaths annually. Cholera is a major cause of ill-health in Africa and Uganda. This study aimed to determine the physicochemical characteristics of the surface and spring water in cholera endemic communities of Uganda in order to promote access to safe drinking water. METHODS: A longitudinal study was carried out between February 2015 and January 2016 in cholera prone communities of Uganda. Surface and spring water used for domestic purposes including drinking from 27 sites (lakes, rivers, irrigation canal, springs and ponds) were tested monthly to determine the vital physicochemical parameters, namely pH, temperature, dissolved oxygen, conductivity and turbidity. RESULTS: Overall, 318 water samples were tested. Twenty-six percent (36/135) of the tested samples had mean test results that were outside the World Health Organization (WHO) recommended drinking water range. All sites (100%, 27/27) had mean water turbidity values greater than the WHO drinking water recommended standards and the temperature of above 17 °C. In addition, 27% (3/11) of the lake sites and 2/5 of the ponds had pH and dissolved oxygen respectively outside the WHO recommended range of 6.5-8.5 for pH and less than 5 mg/L for dissolved oxygen. These physicochemical conditions were ideal for survival of Vibrio. cholerae. CONCLUSIONS: This study showed that surface water and springs in the study area were unsafe for drinking and had favourable physicochemical parameters for propagation of waterborne diseases including cholera. Therefore, for Uganda to attain the SDG 6 targets and to eliminate cholera by 2030, more efforts are needed to promote access to safe drinking water. Also, since this study only established the vital water physicochemical parameters, further studies are recommended to determine the other water physicochemical parameters such as the nitrates and copper. Studies are also needed to establish the causal-effect relationship between V. cholerae and the physicochemical parameters.

Formative research to scale up a handwashing with soap and water treatment intervention for household members of diarrhea patients in health facilities in Dhaka, Bangladesh (CHoBI7 program).

BACKGROUND: During the time a diarrhea patient presents at a health facility, the household members of the patient are at higher risk of developing diarrheal diseases (> 100 times for cholera) than the general population. The Cholera-Hospital-based-Intervention-for-7-Days (CHoBI7) is a health facility-initiated water treatment and handwashing with soap intervention designed to reduce transmission of diarrheal diseases between patients and their household members. The present research aimed to (1) develop a scalable approach to integrate the CHoBI7 intervention program into services provided at government and private health facilities in Bangladesh; and (2) tailor the intervention program for the household members of all diarrhea patients, irrespective of the etiology of disease. METHODS: We conducted 8 months of formative research, including 60 semi-structured interviews, 2 group discussions, and a pilot study. Thirty-two interviews were conducted with diarrhea patients and their family caregivers, government stakeholders, and health care providers both to explore existing WASH and diarrhea patient care practices in health facilities and to identify considerations for scaling the CHoBI7 program. Fifty-two diarrhea patient households participated in a pilot study of a modified version of the CHoBI7 intervention program for tailoring. Twenty-eight interviews and 2 group discussions were conducted with pilot households to explore experiences with and recommendations for intervention delivery. RESULTS: The intervention program was modified based on formative research findings. Pilot study participants recognized the benefits of the CHoBI7 intervention program and made suggestions to improve the acceptability and feasibility of the intervention. Modifications included 1) providing additional pictorial modules, cues to action, enabling technologies, and supplies for safe drinking water and handwashing with soap behaviors in the health facility; 2) switching out technology prone to breaks and leaks as well as sourcing plastic technologies from a high-quality, local manufacturer; and 3) including instructions discouraging the non-use or misuse of technologies and supplies. Considerations for scalability include the local availability and marketing of enabling technologies and supplies, staff for program delivery in health facilities, and potential integration into existing government or health promotion programs. CONCLUSIONS: Formative research identified important considerations for the content, delivery, and scalability of the CHoBI7 health facility-initiated WASH intervention program.

Formative research for the design of a scalable water, sanitation, and hygiene mobile health program: CHoBI7 mobile health program

BACKGROUND: The Cholera-Hospital-Based-Intervention-for-7-Days (CHoBI7) is a handwashing with soap and water treatment intervention program delivered by a health promoter bedside in a health facility and through home visits to diarrhea patients and their household members during the 7 days after admission to a health facility. In a randomized controlled trial among cholera patient households in Bangladesh, the 7-day CHoBI7 program resulted in a significant reduction in cholera among household members of cholera patients and sustained improvements in drinking water quality and handwashing with soap practices 12 months post-intervention. In an effort to take this intervention to scale across Bangladesh in partnership with the Bangladesh Ministry of Health and Family Welfare, this study evaluates the feasibility and acceptability of mobile health (mHealth) programs as a low-cost, scalable approach for CHoBI7 program delivery. METHODS: Formative research for the development of the CHoBI7 mHealth intervention included 40 semi-structured interviews, 4 mHealth workshops, 2 group discussions, and a pilot study of 52 households to assess the feasibility and acceptability of the developed mHealth program. Thematic analysis of the interviews and group discussions was conducted by two individuals separately based on emergent themes, and then themes were compared and discussed. RESULTS: A theory- and evidence-based approach using qualitative research methods was implemented to design the CHoBI7 mHealth program. Semi-structured interviews with government stakeholders identified perceptions and preferences for scaling the CHoBI7 mHealth program. Group discussions and semi-structured interviews with diarrhea patients and their family members identified beneficiary perceptions of mHealth and preferences for CHoBI7 mHealth program delivery. mHealth workshops were conducted as an interactive approach to draft and refine mobile message content based on stakeholder preferences. The pilot findings indicate that the CHoBI7 mHealth program has high user acceptability and is feasible to deliver to diarrhea patients that present at health facilities for treatment in Bangladesh. Both text and voice messages were recommended for program delivery. Dr. Chobi, the sender of mHealth messages, was viewed as a credible source of information that could be shared with others. CONCLUSION: This study presents a theory- and evidence-based approach that can be implemented for the development of future water, sanitation, and hygiene mHealth programs in low-resource settings.

Correction to: Formative research for the design of a scalable water, sanitation, and hygiene mobile health program: CHoBI7 mobile health program.

It was highlighted that the original article [1] contained an error in the title. Additionally, Table 2 contained a typesetting mistake. This Correction article shows the incorrect and correct article title and Table 2. The original article has been updated.

Human Experimental Challenge With Enterotoxigenic Escherichia coli Elicits Immune Responses to Canonical and Novel Antigens Relevant to Vaccine Development.

Background: Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrheal illness in the developing world. Enterotoxigenic E coli vaccinology has been challenged by genetic diversity and heterogeneity of canonical antigens. Examination of the antigenic breadth of immune responses associated with protective immunity could afford new avenues for vaccine development. Methods: Antibody lymphocyte supernatants (ALS) and sera from 20 naive human volunteers challenged with ETEC strain H10407 and from 10 volunteers rechallenged 4-6 weeks later with the same strain (9 of whom were completely protected on rechallenge) were tested against ETEC proteome microarrays containing 957 antigens. Results: Enterotoxigenic E coli challenge stimulated robust serum and mucosal (ALS) responses to canonical vaccine antigens (CFA/I, and the B subunit of LT) as well as a small number of antigens not presently targeted in ETEC vaccines. These included pathovar-specific secreted proteins (EtpA, EatA) as well as highly conserved E coli antigens including YghJ, flagellin, and pertactin-like autotransporter proteins, all of which have previously afforded protection against ETEC infection in preclinical studies. Conclusions: Taken together, studies reported here suggest that immune responses after ETEC infection involve traditional vaccine targets as well as a select number of more recently identified protein antigens that could offer additional avenues for vaccine development for these pathogens.

Immunogenicity and Protection From a Single Dose of Internationally Available Killed Oral Cholera Vaccine: A Systematic Review and Metaanalysis.

In addition to improved water supply and sanitation, the 2-dose killed oral cholera vaccine (OCV) is an important tool for the prevention and control of cholera. We aimed to document the immunogenicity and protection (efficacy and effectiveness) conferred by a single OCV dose against cholera. The metaanalysis showed that an estimated 73% and 77% of individuals seroconverted to the Ogawa and Inaba serotypes, respectively, after an OCV first dose. The estimates of single-dose vaccine protection from available studies are 87% at 2 months decreasing to 33% at 2 years. Current immunologic and clinical data suggest that protection conferred by a single dose of killed OCV may be sufficient to reduce short-term risk in outbreaks or other high-risk settings, which may be especially useful when vaccine supply is limited. However, until more data suggest otherwise, a second dose should be given as soon as circumstances allow to ensure robust protection.