Research Projects : Export

Objective

Evaluate the effectiveness of the Case Area Targeted Intervention (CATI) approach in reducing the incidence of new cases during cholera outbreaks.  And in so doing, to determine factors that support optimal delivery and interventions for CATIs towards cholera reduction in humanitarian settings and fragile states.

Aim

The primary aim is to characterize the relationship between CATI activation time (time between case presentation at a cholera treatment facility and the start of the CATI intervention) and cholera incidence in the area covered by CATI interventions. Secondary aims include:

• Document procedures of implementing CATIs and develop recommendations to maximize their impact in future cholera outbreaks.
• Describe the integration of water, sanitation, and hygiene (WASH) and health activities delivered via CATI.
• Characterize the relationship between CATI completeness (in terms of coverage within the specified geographic area and activities implemented within households) and incidence of new cholera cases.
• Estimate CATI effectiveness using secondary parameters (e.g. reported diarrheal incidence, free chlorine residual (FCR) in the drinking water sample, and knowledge and practices to prevent cholera transmission).
• Document coordination mechanisms between Ministries, United Nations (UN) agencies, Clusters, and non-governmental organizations (NGOs) and develop recommendations for coordination in future responses.

Study Design

The proposed research will be conducted in future cholera outbreaks that take place in recognized humanitarian contexts in at least two different countries; locations will be selected based on where cholera outbreaks occur and the presence of a CATI implementing partner.  Organizations that frequently implement CATI interventions during cholera response that have agreed to partner with JHSPH include Action Against Hunger, Solidarités International, and Medair. Countries with humanitarian emergencies that are at high risk of cholera outbreaks include Democratic Republic of the Congo, Nigeria, Ethiopia, Mozambique and Yemen, though it is possible that other humanitarian contexts may serve as a research location if a cholera outbreak occurs and one of the aforementioned implementing partners responds with a CATI intervention.

The JHSPH IRB approval has classified this study as Non-Human Subjects Research.   Government or IRB approval will be attained prior to conducting the research.

The research team will be present at the site as soon as possible after the first cholera case has been documented and begin data collection as soon as feasible. If travel to the study location is not feasible for security reasons, the JHSPH research team will conduct the study remotely through the partner organization that is providing on-the-ground CATI response to the cholera outbreak.

Because the aim of the research is to evaluate CATIs as delivered by NGOs in response to a cholera outbreak, a randomized design is not possible. Thus, we will rely on comparison groups that will occur naturally, according to the outbreak size and capacity of the response organization. This will necessitate a flexible sampling approach.

We anticipate the primary comparison will be rapid vs. delayed CATI implementation (e.g. end stage of outbreak); however, it is also possible that areas with no CATI implementation could be used as a comparison group [in outbreaks where there is insufficient capacity to respond to all cases].  Additional points of comparison may include the delay between case presentation and CATI implementation:  e.g. CATI implemented within 24h, in 2 days, in 3 days, in 4 days, etc.

The proposed research is an observational study of cholera interventions implemented by NGOs in response to cholera outbreaks (i.e. no intervention is proposed).  The study will include the following components:

• Observation of CATI delivery
• Key informant interviews: 1) NGO staff members delivering the CATI intervention to characterize perceived strengths and weakness of the intervention, household selection, logistical processes and implementation challenges; 2) Humanitarian response managers from the partner NGO, UN agencies, national governments and other organizations engaged in the cholera response to ascertain perceptions of the response, coordination and CATI delivery and implementation
• Cholera treatment facility line lists: Information from cholera line lists is used to plan CATI interventions, where each individual on the line list (i.e. a cholera case) receives a household visit from a CATI team. The JHSPH study team will request line lists from health facilities [which may be augmented by the study team] to evaluate coverage of CATI interventions.
• Follow up survey: The household follow up survey will be conducted approximately 14 days after the presentation of the suspected cholera case at a cholera treatment facility. The exact sampling approach will depend on the density of housing in the community and the CATI implementation strategy. Household surveys will enquire about receipt of the CATI intervention, household composition, incidence of diarrhea and diarrhea care seeking among household members in the period since CATI implementation (or case presentation if there was no CATI), knowledge and practices of hygiene behaviors and observation of free chlorine level (FCR) in stored drinking water.

Cholera continues to pose a major global public health threat and is a marker of inequality and poverty as it reflects the lack of access to basic water and sanitation infrastructures. The risk of the spread of cholera is particularly high in humanitarian settings and fragile contexts.

Cholera transmission risk is higher for cholera case household members and nearby households. Mass interventions to contain cholera outbreaks are not resource efficient.  Preventive interventions targeting cholera case-households and neighbors have been found effective in past outbreaks. These interventions are often referred to as case area targeted interventions (CATIs). CATIs predominantly include water, sanitation, and hygiene (WASH) activities but can also include epidemiological surveillance, and health (clinical) services, primarily oral vaccination and antibiotic chemoprophylaxis.

There are limited studies on the best practices and effectiveness of CATIs in humanitarian settings.   This study aims to identify those factors that support optimal delivery and interventions of these CATIs for cholera reduction in humanitarian settings and fragile states.  The study design centers around observing the CATI activities of partner organizations as they respond to a cholera outbreaks in known humanitarian or fragile settings.

There is limited evidence studying the mechanisms, composition, interventions, timing, effectiveness of CATIs in humanitarian settings. This proposed research for CATI in humanitarian settings will focus on variations in CATI implementation and timing, monitoring and evaluation, and coordination and integration with the aim of expanding available evidence that can be used to inform the development of operational guidance for CATI interventions in cholera response.

Burden

Cholera remains a major global health problem, resulting in more than 100,000 deaths and several million cases annually. Bangladesh, which lies in the Ganges River Delta, is a hyper endemic country and has an estimated 300,000 cholera cases and over 4,500 deaths annually. In early 2020, the SARSCoV-2 pandemic shocked the world leading to over 43 million cases and over 1 million deaths globally by October 2020. In Bangladesh, by October 2020, there have been an estimated 400,000 cases and over 5,000 deaths. With the implementation of non-pharmaceutical interventions like social distancing, healthcare seeking behaviors have likely been affected resulting in the likely underestimation of both cholera and COVID-19 cases.

Knowledge gap

To meet the ambitious goals set by the WHO of reducing cholera as a public health threat by 2030 and reduce cholera in the hyper endemic setting of Bangladesh, improving our methods for counting cholera cases and infections is critical for control planning. At present, most cholera burden estimates are derived from passive clinical based surveillance, which only captures a portion of true cases and infections due to barriers to healthcare seeking. While we have recently developed methods to estimate V. cholera infection incidence at the population-level, some fundamental questions still remain on how to interpret this data in relation to clinical incidence. Furthermore, we know little about how the COVID-19 pandemic has affected healthcare seeking for cholera or what the seroprevalence of SARS-CoV-2 is in the population.

Relevance

Results from this study will improve our knowledge of cholera incidence in Bangladesh to aid the distribution of interventions like the oral cholera vaccine. Refining our methods for estimating cholera burden will additionally improve how we estimate cholera burden in other countries and estimate future vaccine demand. This study will also result in the estimation of the seroprevalence of SARSCoV- 2 infection in the study region in Bangladesh which will help inform the implementation of
interventions like vaccination and improve our understanding of how the COVID-19 pandemic has disrupted healthcare seeking behaviours.

Objectives

The primary objective of this study is to improve and refine our methods for estimating correlates of cholera burden from cross-sectional serosurveys though enhanced clinical surveillance of cholera at two healthcare facilities and through serial serosurveys. A secondary objective of this study is to better understand the maturity of the SARS-COV-2 epidemic in this population by measuring the prevalence of SARS-COV-2 antibodies in the population and estimating key individual-, household- and
community-level risk factors for infection.

Study Site

This study will be focused at two healthcare facilities, the Bangladesh Institute of Tropical Infectious Diseases (BITID) and the Sitakunda Upazila Health Complex (UHC), and their catchment population, the Sitakunda Upazila within the Chittagong District in South Eastern Bangladesh. Historical clinical and serologic surveillance from the district suggest that cholera incidence is relatively high compared to other parts of Bangladesh (e.g.,1.15 times the seroincidence than the mean for the country based on a serosurvey conducted in 2015) with two seasonal peaks in cholera admissions, the larger one typically starting in March and the smaller one towards the end of the calendar year. Clinical surveillance data from 2014-2018 illustrate that a greater number of patients with acute watery diarrhea visit BITID from April to June; on average approximately 4,000 individuals seek care at BITID for acute watery diarrhea within a single year. We anticipate that within a 18-month period,
approximately 9,000 patients will seek care at both BITID and the Sitakunda UHC.

Cholera remains a major global health problem, resulting in more than 100,000 deaths and several million cases annually. Bangladesh, which lies in the Ganges River Delta, is a hyper endemic country and has an estimated 300,000 cholera cases and over 4,500 deaths annually. In early 2020, the SARS-CoV-2 pandemic shocked the world leading to over 43 million cases and over 1 million deaths globally by October 2020. In Bangladesh, by October 2020, there have been an estimated 400,000 cases and over 5,000 deaths. With the implementation of non-pharmaceutical interventions like social distancing, healthcare seeking behaviors have likely been affected resulting in the likely underestimation of both cholera and COVID-19 cases.

The primary objective of this study is to improve and refine our methods for estimating correlates of cholera burden from cross-sectional serosurveys though enhanced clinical surveillance of cholera at two healthcare facilities and through serial serosurveys. A secondary objective of this study is to better understand the maturity of the SARS-COV-2 epidemic in this population by measuring the prevalence of SARS-COV-2 antibodies in the population and estimating key individual-, household- and community-level risk factors for infection.

Our primary study outcome is the change in seroincidence between the first and third serosurvey to capture changes in cholera incidence over the course of the typical high and low season at the study site. Our secondary outcome is the prevalence of anti-SARS-CoV-2 antibodies among individuals in the first serosurvey. We will explore the associations between seropositivity (for cholera and SARS-COV-2) and different individual-, household- and community-level risk factors collected in the surveys, including WASH attributes and factors like population density, travel time (to the nearest city), distance to a major water body, community water and sanitation coverage, and poverty.

Burden

Beginning in Asia in 1961, the 7th cholera pandemic spread world-wide, reaching in Africa in 1970, and finally South America in 1991. A massive epidemic exploded in Peru in January 1991, spread rapidly from south to north of Latin America, and reached Mexico in June causing thousands of deaths. Since America was affected badly after about a century of no cholera, naturally the source of the disease was an enigma. Several studies in the past proposed contrasting views about the source, some arguing about a local source while others believed cholera to be an extension of 7th pandemic El Tor from Asia; although disease was rampant since 1991 and continuing throughout the continent causing morbidity and mortality in South and Central America.

Knowledge gap

A recent retrospective study on V. cholerae isolated from clinical and environmental sources in Mexico, between 1991 and 1997, confirmed both classical and El Tor biotypes with the latter presenting distinct genotypic and phenotypic traits including strains that had variants having a combination of classical biotype characteristics under the El Tor background. These results appeared in a sharp contrary to what has been proposed for the cholera in the Americas to be of Asian origin as El Tor was the only circulating biotype shown in Peru until recently. In order to further understand the evolutionary trends of bacteria causing endemic cholera in Mexico, we propose to carry out an extensive study on V. cholerae strains isolated from endemic cholera between 1998 and 2008. This study is vital for us to understand the evolutionary trend in terms of the prevalent sero-biotypes of V. cholerae to be able to develop a unified global model for intervention and preventive measures.
Relevance: Cholera is a pandemic disease claiming millions of lives globally. Efforts are being made to improve the understanding of cholera and V. cholerae associated with the disease globally. The America was affected badly after about a century of no cholera, and so very little is known about V. cholerae associated with the disease. The proposed study will generate important data on the phenotypic and genotypic traits of V. cholerae causing endemic cholera in Mexico during 1998 – 2008. The data obtained will help us to develop a unified global approach for intervention and preventive measure against cholera globally.

Hypothesis

After 1991 outbreaks in Latin America, cholera continues to be endemic in many countries of the Americas including Mexico. Our recent retrospective study on V. cholerae isolated between 1991 and 1997 showed the association of biotypes classical, El Tor, and El Tor variants with the endemic cholera in Mexico (Alam, et al., with H. Watanabe, M. Morita…A. Cravioto (JCM 2010). We hypothesis that the V. cholerae associated with endemic cholera is evolving independently in Mexico. The proposed follow-up study will generate important microbiological, molecular and phylogenetic data on V. cholerae causing endemic cholera in Mexico to be able to develop a unified global model for intervention and preventive measure against cholera globally.

Objectives

The aim of this study is to understand the latest status of cholera bacteria in Mexico, particularly to determine the prevalent sero-biotypes of V. cholerae and their clonal nature to develop a unified global approach for intervention and preventive measure against cholera world-wide.

Methods

V. cholerae isolated from endemic cholera in Mexico during 1998 – 2008 will be subjected to extensive phenotypic, molecular, and phylogenetic analysis. For this, we will involve serology, antimicrobial assay, multi-locus genome scanning (by simplex and multiplex PCR) and sequencing of targeted genes. DNA fingerprinting will be determined by molecular tools such as PFGE and the data will be analyzed by bionumeric software. Dendrograms will be generated by using appropriate computational tools.

Cholera is unheard of for a century from Latin America, and so is the V. cholerae. This sudy was designed to characterize V. cholerae associated with Latin American cholera in 1991 and subsequent years.

Better understanding of the phenotypic and gentypic characteristics will aid in deciding intervention and preventive measures against cholera.

Burden

Cholera has been well-established as a seasonal disease that varies in the patterns of infections. The seasonal outbreaks of cholera occurs in multiple endemic foci of Bangladesh, most showing a single annual peak like in other cholera affected regions of the world. However, cholera shows two distinct seasonal peaks, one before (March – May) and the other after (September – November) the annual monsoon [6] in Dhaka and Matlab, Bangladesh. V. cholerae has been established as an autochthonous flora of brackish waters and estuarine ecosystems [11] where the bacterium shares niche, and is found in association with plankton [12]. Although sea surface temperature has been shown to have a degree of correlation with the incidence of cholera in Bangladesh [13], little is known about how these factors contribute to the seasonal cholera outbreaks in the freshwater environments of Dhaka and Matlab, which are 50km apart, and 350 km away from the coast of Bay of Bengal. Historically, most major epidemics have originated in the coastal regions, including the O139 Bengal outbreaks that originated in the Bay of Bengal villages of India and Bangladesh. In Dhaka and Matlab, endemic cholera occurs in distinctive two-peak pattern, before and after the monsoon [1,14], although the diseases continues even beyond the defined seasons and can appear as off-season peaks affecting many.

Knowledge gap

In August 2007, Bangladesh suffered flooding, which was accompanied by a large diarrhea outbreak in Dhaka city just prior to the usual fall peak that followed. During this outbreak, the ICDDR,B Dhaka hospital treated a record number of cholera patients peaking at 1045 patients per day, with 70% suffering from severe dehydration. Although V. cholerae O1 ET was the etiological agent, the detail characteristics of the bacterium causing increasing severity of cholera including the natural factors driving the off-season epidemics remain important to be explored.

Relevance

This study will generate important data on the climate factors, and phenotypic (antibiogram), molecular, and phylogenetic characteristics of V. cholerae ET associated with the severe disease outbreak of seasonal and off-season cholera. The data will aid in formulating therapeutic intervention and preventive measures against the deadly disease.

Hypothesis

The seasonal and off-season cholera outbreaks have different hydro-climatic drivers in Bangladesh, and the increased severity of 2007 flood outbreak might be the result of fecal-oral transmission of hyper-infectious V. cholerae.

Objectives

• To study the phenotypic, molecular, and phylogenetic characteristics of V. cholerae associated with severe disease outbreak of seasonal and off-season cholera in 2007.
• To analyze the regional hydroclimatological data for over 30-35 years (1980s – 2018) to understand the natural driver(s) of cholera.

Methods

An estimated 1000 V. cholerae strains from seasonal and off-season cholera outbreaks in 2007 and in the subsequent years, up to 2018, would be included in this study. V. cholerae strains will be collected from routine 2% hospital surveillance samples at Dhaka hospital of icddr,b at an estimated number of 80 – 100 strains/year for phenotypic, molecular and phylogenetic analyses, including multilocus genetic screening by simplex and multiplex-PCR, sequence-typing of the genes (namely ctxB), pulsed-field gel electrophoresis (PFGE), and whole genome sequencing (WGS). No patient data will be collected in this study other than the date of hospital enrolment to keep temporal records of the infections. Role of climate and related factors e.g., hydroclimatological data such as annual water flow in the major basins, temperature, rainfall, humidity etc. associated with the unusual incidence of cholera cases suffering from severe disease will also be determined.

This study was designed to characterize V. cholerae responsible for the seasonal and off-season cholera outbreaks in Dhaka.

Unveiling the clonal type responsible for seasonal and off-season cholera outbreaks is crucial to decide intervention and preventive measures against cholera.

Burden

Cholera, a scourge, remains one of the major causes of morbidity and mortality world-wide. The global burden of cholera is estimated to be about 3-5 million cases each year with an estimated deaths of 100,000 to 120,000, majority occurring in the developing countries of Asia and Africa. The causative agent of cholera, Vibrio cholerae, is a genetically versatile bacterial species for which more than 200 serogroups have been identified and for which significant lateral transfer of genes has been demonstrated. Pandemic cholera is generally caused by toxigenic strains of V. cholerae serogroups O1 and O139. V. cholerae O1 has been divided into two biotypes, classical (CL) and El Tor (ET), differing primarily in phenotypic traits and distinct signature genome sequences. Of seven cholera pandemics recorded since 1817, the sixth and presumably the earlier pandemics have been caused by CL biotype, which was replaced in the 1980s by ET biotype initiating the currently ongoing seventh cholera pandemic. The Ganges Delta of the Bay of Bengal has been the traditional home where cholera is endemic for centuries. Although V. cholerae has been an integral part of the bacterial community sharing niche in the estuarine ecosystem of Bay of Bengal, little is known about the aquatic life cycle of V. cholerae, particularly how a pandemic pathogen emerges from the naturally occurring benign population residing this historic ecosystem.

Knowledge gap

Despite intensive research efforts have been made to understand the epidemiology and ecology of V. cholerae, of its physiology and mode of infection in laboratory and in animal model systems, our knowledge is very limited and we still do not fully understand the molecular basis of pathogenicity of the bacterium and why cholera is a seasonal disease, and how a pandemic pathogen takes shape from among the diverse population occurring in the historical niche of the Bay of Bengal estuaries and spread.

Hypothesis

Since cholera has been endemic in the coastal villages of Bay of Bengal (Bangladesh), we hypothesize that the toxigenic V. cholerae responsible for the century-old Asiatic cholera is an integral part of the estuarine vibrio community that are influenced by the local climate, and includes ecological types (ecotypes) unique for this ecosystem.

Objectives

Our primary aim is to:

• Study the population structure (ecotypes) of V. cholerae occurring in the estuarine aquatic ecosystems of the Bay of Bengal

Our secondary aim is to:

• Understand how the naturally occurring toxigenic V. cholerae population (ecotypes) responds to the seasonal change in the regional climate to initiate seasonal cholera.
• Determine virulence potential of epidemiologically significant V. cholerae and related enteric pathogens of environmental and clinical origin by molecular and animal model assays.
• Decipher the transmission of epidemiologically significant V. cholerae regionally, and beyond. For this, we will compare the population structure, virulence and related molecular traits of V. cholerae occurring in the Bay of Bengal estuaries with that of the US east coast (Chesapeake Bay and Falmouth MA), for example.
• Determine antimicrobial resistance (AMR) of environmental and clinical strains of V. cholerae and related enteric pathogens.

Methodologies

V. cholerae (n=2100) would be isolated by culture method from water samples collected monthly from 8 selected Bay of Bengal estuarine pond and river sites located at the cholera-endemic coastal villages of Potuakhali, Bangladesh. Water samples would be collected aseptically in sterile Nalgene bottle and transferred to icddr,b Dhaka hospital for microbiological analysis. “

We designed this study to monitor and characterizing naturally occurring V. cholerae initiating seasonal (endemic) cholerea in Bangladesh.

Genetic tracking of Vibrio cholerae in its natural aquatic environments to provide insights that will aid prediction and preventive measures against upcoming cholera in Bangladesh

Burden

Cholera, a scourge, causes significant morbidity and mortality world-wide, especially in the Ganges Delta of Bangladesh. The global burden of cholera is estimated to be about 3-5 million cases each year with an estimated deaths ranging from 100,000 to 120,000, and majority occurring in the developing countries of Asia and Africa, including Bangladesh. Despite intense researches have been done on the epidemiology and ecology of V. cholerae, including its virulence, mode of infection in laboratory and in animal model systems, our knowledge is limited in regards the vibriophages of their role in the V. cholerae pathogenicity, seasonality of the disease cholera, and the ecology of the bacterium in the natural estuarine environments of Bangladesh.

Knowledge gap

Vibriophages play a critical role in pathogenicity and in controlling the seasonal outbreaks of cholera in Dhaka, Bangladesh, although research on the role of vibriophages on the V. cholerae pathogenicity, seasonality of the disease cholera, and the ecology of the bacterium responsible for endemic cholera in the coastal and estuarine environments remains an important area to be explored.

Relevance

Vibriophages have been known to play an important role in virulence of V. cholerae and in controlling the seasonal outbreaks of cholera; however, our knowledge is limited about how phages contribute to V. cholerae pathogenicity, seasonality of the disease cholera, and the ecology of the bacterium in estuarine villages of Bangladesh. The study findings will be useful for designing therapeutic intervention and preventive measures against deadly disease cholera.

Hypothesis

We hypothesize that the vibriophages present in the coastal and estuarine environment play an important role on the V. cholerae (O1, O139, and non-O1/O139) pathogenicity, seasonality of the disease, and the ecology of the bacterium responsible for endemic cholerain the coastal and estuarine aquatic environments of the Bay of Bengal, Bangladesh.

Objectives

This study aims to understand the genetic diversity of specific vibriophages playing important role in the pathogenicity, epidemiology and ecology of V. cholerae in the coastal and estuarine environments of Bangladesh.

Methods

Both vibriophages and toxigenic V. cholerae (O1, O139, and non-O1/O139) will be collected from cholera patients and from estuarine environment of Mathbaria for two years, during 2016-2018. Environmental parameters such as temperature, turbidity, pH, salinity, and conductivity will be measured on site, and both stool and water samples will be collected, cryo-protected and stored in -20oC freezer for vibriophage and V. cholerae isolation following enrichment in APW broth. Samples will be transported to icddr,b Dhaka hospital for further analysis. V. cholerae isolates and an aliquot of each sample will be shipped to USA for vibriophage isolation and critical characterizations by sequencing both. Vibriophage and toxigenic V. cholerae will also be isolated from cholera stool samples collected simultaneously from icddr,b Dhaka hospital for comparison.

Outcome measures/variables

This study will generate invaluable information on the nature of the vibrio phages, their seasonal dynamics, interrelationships, virulence, and disease transmission. The data generated would be important because the Bay of Bengal estuary is the historical reservoir for V. cholerae causing Asiatic cholera, and its specific phages.

Phages predate on V. cholerae and plays a role in shaping up of the epidemic clone. We designed this study to unveil the impact of phages on the Vibrio cholerae life cycle in Bangladesh.

The seasonality and dynamics of phages, and their interaction with Vibrio cholerae will aid prevention of cholera transmission.

Burden

Cholera, caused by V. cholerae, is a killer disease. In Bangladesh, cholera occurs endemically at defined seasons resulting significant morbidity and mortality each year. V. cholerae is a native flora of the estuarine aquatic environment. The bacterium existing in the environment is found mostly in a dormant, non-cultivable state; and can regain active state and flourish to initiate the seasonal epidemics of cholera. Although seasonal cholera is driven by natural climate factors, the disease takes the turn of epidemic through rapid transmission of infectious V. cholerae via fecal-oral mode as marginal people relies on contaminated surface water for drinking and other domestic purposes.

Knowledge gap

We want to understand V. cholerae growth response, particularly what triggers the bacterium to be active from dormant non-culturable state, and if locally available no-cost items such as ashes could kill the infectious bacterium shed in stool to decontaminate the environment; the aim is to develop a sustainable method to prevent cholera transmission.

Relevance

This study will generate knowledge on V. cholerae growth responses, and no-cost method of stool decontamination, and the aim is prevent cholera transmission.

Hypothesis

• Climatic and human factors contribute to active growth of V. cholerae responsible for seasonal cholera to prevent cholera transmission
• Wood ashes might provide a sustainable method of stool decontamination to prevent V. cholerae transmission

Objectives

• Study the environmental and human factors activating naturally occurring non-cuturable V. cholerae that initiates seasonal cholera
• Test efficacy of wood ashes in decontaminating V. cholerae shed in stools to reduce cholera transmission

Methods

Water samples will be collected from four Mathbaria sites, and temperature, turbidity, pH, salinity, total dissolved solids and conductivity of water monitored bi-weekly during March-May and September-November and monthly for the rest of the year. Toxigenic V. cholerae will be isolated (Alam et al. 2006a) and characterized in terms of virulence adaptive polymorphisms (VAPs) and molecular fingerprinting. Also, laboratory microcosms will be constructed with two toxigenic V. cholerae to test growth response of the bacterium, and the role of cyanobacteria (Islam et al., 1990a; Islam et al., 1990b) and bile will be monitored at different temperatures, pH, salinity, and conductivity. In this study, efficacy of decontamination of discarded diarrheal stools carrying V. cholerae would be monitored and compared with commercially available disinfectant such as bleaching powder.

Outcome measures/variables

Growth response of V. cholerae to different climate factors, and the role of cyanobacteria and bile in microcosms would be an outcome to measure. V. cholerae burden in cholera stool at different concentrations and time of treatment with wood-ashes would also be an outcome measure.

Vibrio cholerae often escapes culturing methods while in a dormant and non-culturable state in the aquatic environment, although they can become actively growing to cause seasonal epidemicsof cholera. We designed this study to unveil the climate and/or natural no-cost substaces that could drive the growth responses of the bacterium to be able to aid diseases prevention in endemic settings.

Vibrio cholerae is an aquatic bacterium which passes the interepidemic period in a dormant and non-culturable state. The well-defined climate or natural factors driving the growth responses of the bacterium could aid in diseases prevention in endemic settings.

Burden

Cholera is a deadly disease with approximately 3-5 million cases and over 1,00,000 deaths annually worldwide. Cholera is a seasonal disease caused by the bacterium V. cholerae which is autochthonous to the aquatic environment. Although it is well established that the disease transmits through water rapidly giving rise to large epidemics, factors contributing to the seasonality of cholera by activating the bacterium persisting in biofilms and in association with planktons in the environment and linkage between archived and newly disseminating 7PET sublineages, remain a longstanding question to answer.

Knowledge gap

Combined these data suggest that areas of high cholera incidence in Africa and during the 1990’s in Latin America, can be viewed as sinks for the epidemic cholera causing lineage 7PET and not the original source. Whilst data supporting this are substantive, we lack a detailed whole genome view of the environmental isolates of V. cholerae (O1, O139, and non-O1/non-O139) from Inland, coastal and estuarine environments of West Bengal and Northern regions of India and Bangladesh, the South Asian ‘hotspot’ of epidemic cholera.

Relevance

Unveiling the natural climatic factors that contribute to the seasonal epidemics of cholera would be of preventive implication. If we are to understand the drivers behind the emergence and spread of newly disseminating 7PET sublineages then we must focus attention on the Ganges Delta region, understanding how and where its unique ecology supports the emergence and spread of epidemic V. cholerae.

Hypothesis

The environmental Vibrio cholerae population in the Bay of Bengal supports the emergence of pandemic cholera

Objectives:

The specific objectives of this project are as follows:

• Generate a long term genomic view of environmental V. cholerae in Bangladesh from live archived samples to understand their evolutionary dynamics and their relationship to 7PET epidemic V. cholerae
• Link genome evolution of V. cholerae to environmental conditions and flux

Methods

Environmental surveillance will be conducted at six river sites of Dhaka, the capital of Bangladesh; five pond and one river sites of Mathbaria, coastal village of Bangladesh; and six river sites of Chhatak, a northern district of Bangladesh. Environmental water samples will be collected bi-weekly during seasonal epidemics of cholera i.e. during March-May and September-November at Dhaka and Mathbaria, September-November at Chhatak and monthly during the rest of the year. The samples will be monitored for environmental parameters such as temperature, turbidity, pH, salinity, total dissolved solids and conductivity. Samples will be transferred to icddr,b central Laboratory at Dhaka at ambient temperature for further analyses (Alam et al. 2006a). Toxigenic V. cholerae will be isolated from the water samples following standard culture methods, and characterized locally at icddr,b (Alam et al. 2006b, c) and also, shipped to Wellcome Sanger Institute, UK for whole genome sequencing.

Outcome measures/variables

Through the collaboration this proposal brings together expertise in high throughput genomics and world leading cholera environmental microbiology and public health in three countries. This will enable a much-needed multidisciplinary research programme to understand the emergence of 7PET. Expected outcomes are i) the publication of research findings in International journals ii) deposition of genome scale data sets in databases for future use iii) a comprehensive genomic understanding of how the 7PET lineage emerge from this region to cause outbreaks globally v) data that will inform cholera control strategies through the WHO Global Task Force for cholera control.

Genome sequencing data can reliably be used for source tracking and mode and route of transmission of a pathogen. The 7th pandemic El Tor is transmitted globally, but the sources is believed to be Asia. We designed this study to have a comprehensive genomic view to understand how the 7PET lineage emerges from this region and spread globally; aim is to control cholera.

A comprehensive genomic view will allow us to understand how the 7PET lineage emerges from this region to cause outbreaks globally; and to inform cholera control strategies through the WHO Global Task Force for cholera control.

Background

Cholera is a rapidly dehydrating diarrheal illness and remains a global threat to public health. Recently it has been estimated that there are approximately 2.8 million cholera cases and 91,500 cholera deaths in cholera-endemic countries. Till date, no medication exists which can quickly curtail cholera diarrhea.

Knowledge gap

Currently, there have not been studies to understand whether vasoactive intestinal polypeptide (VIP) is a mediator in the pathogenesis of cholera.

Relevance

If VIP is a mediator for cholera diarrhoea, VIP antagonists/blockers could significantly curtail cholera diarrhea. Hopefully this might reduce cholera related morbidity & mortality in endemic countries.

Objectives

To determine VIP levels in cholera ricewater stool and in patients’ plasma obtained simultaneously, both before and after correction of severe dehydration using standard intravenous rehydration and maintenance therapy. Thus to confirm a role of VIP in cholera pathophysiology.

Methods

This would be a descriptive study, patients of either sex, aged 18-64 years attending the Dhaka Hospital of icddr,b with severe dehydration due to cholera will comprise the study population. Rectal catheter stool & venous blood specimen will be obtained just before initiation of IV rehydration therapy, after post rehydration, 24 hours after post rehydration & before discharge.

Outcome measures/variables

Primary outcome measure will be stool & plasma VIP level before & after correction of severe dehydration
Secondary outcome measures will be time to cessation of diarrhoea, the total volume of stool output (ml/kg/hr), the total volume of IVF received, and the total volume of ORS received, development of any severe complications, as decided by treating physician.

Cholera is diarrheal illness and can cause severe dehydration rapidly. Cholera remains a global threat to public health. Recently it has been estimated that there are approximately 2.8 million cholera cases and 91,500 cholera deaths in cholera-endemic countries. Till date, no medication exists which can quickly curtail cholera diarrhea. Currently, there have not been studies to understand whether Vasoactive intestinal peptide (VIP) is a mediator in the pathogenesis of cholera. If VIP is a mediator for cholera diarrhoea, VIP antagonists/blockers could significantly curtail cholera diarrhea. Hopefully this might reduce cholera related morbidity & mortality in endemic countries.

If VIP is a mediator for cholera diarrhoea, VIP antagonists/blockers could significantly curtail cholera diarrhea. Hopefully this might reduce cholera related morbidity & mortality in endemic countries.

For over ten years, we have sought how best to develop decision-support tools for clinicians treating diarrhoeal disease. This is important because of a need to rapidly train large numbers of providers during cholera outbreaks, rapidly re-educate when guidelines change, address inappropriate antibiotic use, and allow for differences in epidemiology by season and place. We have built tools in both paper and digital formats, and evaluated their impact in clinical trials. Now, we are collaboratively building digital tools that depend on models developed through machine learning. In a large international collaboration, we have built and evaluated improved algorithms to assess dehydration for children and adults (project led by A. Levine at Brown University) and provide a probability that a patient has only a viral disease based on real-time weather, clinical and epidemiologic data (project led by D. Leung at Utah University). In addition to helping to improve cholera response, these tools represent a significant shift in how clinical decision-support might be in 10 years.

The impact of this research is to first improve rehydration and antibiotic guideline adherence. Secondly, the impact is to make possible dynamic decision-support that is responsive to where and when the patient is being treated.

Background

Globally, the risk of small-scale cholera outbreaks propagating rapidly and enlarging extensively remains substantial. As opposed to relying on mass, community-wide approaches, cholera control strategies could focus on proactively containing the first clusters. Case-area targeted interventions (CATI) are based on the premise that early cluster detection can trigger a rapid, localised response in the high-risk radius around one or several households to reduce transmission sufficiently to extinguish the outbreak or reduce its spread. Current evidence supports a high-risk spatiotemporal zone of 100 to 250 meters around case-households for 7 days.

We hypothesize that the prompt application of CATI will reduce household transmission and transmission in the wider ring. This will result in reduced incidence in the ring and reduced clustering of cases. The local focus of CATI will enable active case-finding and sustained uptake of interventions. This will result in prompt access to care for detected cases, and reduced mortality and community transmission.

Methods

We propose to evaluate the effectiveness of a CATI strategy using an observational study design during an acute cholera epidemic, with clearly-defined measures of the effectiveness of the CATI package. In addition, we intend to evaluate the feasibility, costs, and process of implementing this approach. The CATI package delivered by Médecins Sans Frontières’ (MSF) will incorporate key transmission-reducing interventions (including household-level water, sanitation, and hygiene measures, active case-finding, antibiotic chemoprophylaxis, and, single-dose oral cholera vaccination (OCV)) which aim to rapidly reduce the risk of infection in the household and in the ring around the primary case household. MSF will decide on the contents of the CATI package used, the radius of intervention and the prioritization strategy used if the caseload is higher than the operational capacity, based on national policies, the local context, and operational considerations. In scenarios where preventative vaccination has been recently conducted or is planned, CATI and its evaluation will focus on implementation before and during the mass campaign, or in areas where vaccination coverage was sub-optimal.

The study design is based on comparing the effects of CATIs that rapidly provide protection in averting later generations of cases when compared with progressively-delayed CATIs. A regression analysis will be used to model the observed incidence of enriched RDT-positive cholera as a function of the delay to intervention (in days). The delay will reflect the inverse strength of rapid response. Groups, as a function of their delays to intervention, will serve as internal controls.

Case-area targeted interventions (CATI) are based on the premise that early cluster detection can trigger a rapid, localised response in the high-risk radius around one or several households to reduce transmission sufficiently to extinguish the outbreak or reduce its spread.

We propose to evaluate the effectiveness of a CATI strategy using an observational study design during an acute cholera epidemic, with clearly-defined measures of the effectiveness of the CATI package. In addition, we intend to evaluate the feasibility, costs, and process of implementing this approach. The CATI package delivered by Médecins Sans Frontières’ (MSF) will incorporate key transmission-reducing interventions (including household-level water, sanitation, and hygiene measures, active case-finding, antibiotic chemoprophylaxis, and, single-dose oral cholera vaccination (OCV) ) which aim to rapidly reduce the risk of infection in the household and in the ring around the primary case household.

CATI has been highlighted as a major component of the GTFCC’s global research agenda. Therefore, conducting a rigorous prospective evaluation of the effectiveness of CATI, which includes OCV and explains the pathway to impact, is an important and timely question for outbreak control.

Burden

Cholera is life threatening disease that remains one of the major causes of deaths in the developing countries. Although more than 200 serogroups of V. cholerae reported so far, serogroup O1 and O139 are the major pathogenic strains. Serogroup O1 has two biotypes, classical and El Tor. The classical biotype caused first six cholera pandemics in the Ganges Delta of Bay of Bengal and the other parts of the world. The El Tor biotype of V. cholerae initiated the ongoing 7th pandemic in early 1960s. The El Tor biotype was displaced for a short while in late 1992 when an explosive cholera epidemic occurred by V. cholerae O139 synonym Bengal. O139 however, failed to continue as the predominant epidemic strain and thus V. cholerae El Tor continued to cause the ongoing 7th pandemic.

Knowledge gap

A retrospective study on V. cholerae strains isolated between 1991 and 1997 showed that the biotypes Classical, El Tor, and El Tor variants were involved in endemic cholera in Mexico and ET prototype (wild type) were involved in Peru. We are not aware about the present status of cholera bacteria in different parts of Latin America so; a follow-up study on V. cholerae isolated from 1998 to 2012 was designed.

Hypothesis

The V. cholerae strains causing endemic cholera between 1998 and 2012 in Mexico and other countries of Latin America might not be different in terms of biotype, phenotype, molecular, and phylogenetic properties compared with Asia and Africa.

Objectives

The aim of this study is to determine the prevalent sero-biotypes, molecular status and clonal nature of V. cholerae isolated in Mexico and other Latin American countries and compare those characteristics with the strains isolated from Gangetic Bengal and Africa.

Methods

150 V. cholerae strains (both clinical and environmental) which included 89 strains isolated in Mexico, 45 in Peru, 12 in Brazil, and 6 in Guatemala will be analyzed by culture method, serogrouping and antibiogram. V. cholerae strains will also be subjected to detection of marker genes such as ompW, wbeO1, wbfO139, ctxA and ctxB by PCR. Extensive molecular characterizations using multi-locus genome screening and DNA fingerprinting (phylogeny) by PFGE will also be done.

Outcome measures/variables

This study will generate valuable information on nature (clonal types) of cholera bacteria, their transmission patterns world-wide. This is important because updated information on phenotypic, molecular, and phylogenetic characteristics of V. cholerae associated with cholera in Mexico and other Latin American countries are lacking.

The V. cholerae strains causing endemic cholera between 1998 and 2012 in Mexico and other countries of Latin America might not be different in terms of biotype, phenotype, molecular, and phylogenetic properties compared with Asia and Africa.

Introduction: Adamawa and Bauchi are cholera endemic states in the north-east region of Nigeria, each with local government areas classified as cholera hotspots. Ineffective implementation of multi-sectoral cholera interventions in both states could make obtaining the global target for cholera control in Nigeria out of reach. A major contributing factor to this challenge is fragility of the region due to persistent Boko Haram insurgency activities, often characterised by the destruction of health infrastruture and displacement of communities to areas with suboptimal living conditions. Given the complexity of disease control in such a fragile setting, this study aims to systematically examine the barriers and/or facilitators influencing the implementation of existing cholera interventions in these states.

Methods: The study will use a systems dynamic approach. First, we will conduct a health facility survey to determine the current health system capacity to support multi-sectoral cholera interventions, and conduct key informant interviews with purposely selected state and national cholera stakeholders to identify the context-specific facilitators and barriers to the implementation of cholera interventions in these states. We will then conduct nine group model building workshops (four in both the Adamawa and Bauchi states and one in Abuja) among cholera stakeholders similar to those recruited for the interviews.

Conclusion: By engaging diverse and relevant cholera stakeholders, including community members, this study has the potential to provide a rich understanding of context-specific factors influencing the implementation of multi-sectoral cholera interventions in a fragile region of Nigeria, with a view to achieve sustainable progress towards cholera control in the country.

Adamawa and Bauchi states are cholera endemic states in the north-east region of Nigeria, each with some local government areas classified as cholera hotspots or high burden areas. However, the prevailing activities of armed conflict, as perpetuated by Boko-Haram, in the region could make the implementation of multi-sectoral cholera interventions ineffective. Moreover, addressing disease burden in such fragile settings is particularly challenging. Thus, this study aims to systematically examine the barriers and/or facilitators influencing the implementation of existing cholera interventions in these states.

To achieve these objectives, the study will use a systems dynamic approach, by first conducting a health facility survey to determine the current health system capacity to support multi-sectoral cholera interventions, as well as conducting key informant interviews with purposely selected cholera stakeholders at various levels of government. These research activities will then be followed by a series of participatory workshops (four in both Adamawa and Bauchi states and one in Abuja) among participants with similar characteristics as those in the key informant interviews. It is worth noting that findings from the first phase of the study will be informing the workshop activities.

Overall, by engaging diverse and relevant cholera stakeholders, including community members, this study has the potential to provide a rich understanding of context-specific factors influencing the implementation of multi-sectoral cholera interventions in a fragile region of Nigeria, with a view to achieve sustainable progress towards cholera control in the country.

Nationally, the study would be providing context-specific findings, generated in collaboration with various cholera stakeholders including policymakers and community representatives. Globally, the study is designed around the GTFCC’s global strategic framework, thereby making the potential findings of direct relevance to cholera global stakeholders.

The project is to gain an understanding of the epidemiology of cholera in the Great Lakes Region – Africa to develop tailored prevention investment plans in identified hotspots of Uganda, Tanzania and Burundi.

Specifically, the project is designed to 1) identify hotspots in these countries, 2) develop factsheets on cholera to guide preparedness, 3) and prepare investment plans for for these hotspots. Notably, UNICEF has a method for hotspot mapping which is different from the GTFCC; thus maps using these two methods are presented and compared.

Analyze the epidemiology of cholera in Uganda, Tanzania, and Burundi to prepare hotspot maps and attempt to identify factors that influence cholera rates in these hotspot areas. Based on the identification of these hotspots, the project should prepare recommendations for cholera control using an integrated approach. Eventually, this should result in an investment plan.

The countries should be able to use this information in preparing their National Cholera Control Plans.