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Listening to Communities is Key to Preparing for the Public Health Implications of El Niño in Zambia

Climate Change Impact Map

A review of the environmental trigger and transmission components for prediction of cholera

Climate variables influence the occurrence, growth, and distribution of Vibrio cholerae in the aquatic environment. Together with socio-economic factors, these variables affect the incidence and intensity of cholera outbreaks. The current pandemic of cholera began in the 1960s, and millions of cholera cases are reported each year globally. Hence, cholera remains a significant health challenge, notably where human vulnerability intersects with changes in hydrological and environmental processes. Cholera outbreaks may be epidemic or endemic, the mode of which is governed by trigger and transmission components that control the outbreak and spread of the disease, respectively. Traditional cholera risk assessment models, namely compartmental susceptible-exposed-infected-recovered (SEIR) type models, have been used to determine the predictive spread of cholera through the fecal-oral route in human populations. However, these models often fail to capture modes of infection via indirect routes, such as pathogen movement in the environment and heterogeneities relevant to disease transmission. Conversely, other models that rely solely on variability of selected environmental factors (i.e., examine only triggers) have accomplished real-time outbreak prediction but fail to capture the transmission of cholera within impacted populations. Since the mode of cholera outbreaks can transition from epidemic to endemic, a comprehensive transmission model is needed to achieve timely and reliable prediction with respect to quantitative environmental risk. Here, we discuss progression of the trigger module associated with both epidemic and endemic cholera, in the context of the autochthonous aquatic nature of the causative agent of cholera, V. cholerae, as well as disease prediction.

Water, sanitation and hygiene risk factors for the transmission of cholera in a changing climate: Using a systematic review to develop a causal process diagram

Cholera is a severe diarrhoeal disease affecting vulnerable communities. A long-term solution to cholera transmission is improved access to and uptake of water, sanitation and hygiene (WASH). Climate change threatens WASH. A systematic review and meta-analysis determined five overarching WASH factors incorporating 17 specific WASH factors associated with cholera transmission, focussing upon community cases. Eight WASH factors showed lower odds and six showed higher odds for cholera transmission. These results were combined with findings in the climate change and WASH literature, to propose a health impact pathway illustrating potential routes through which climate change dynamics (e.g. drought, flooding) impact on WASH and cholera transmission. A causal process diagram visualising links between climate change dynamics, WASH factors, and cholera transmission was developed. Climate change dynamics can potentially affect multiple WASH factors (e.g. drought-induced reductions in handwashing and rainwater use). Multiple climate change dynamics can influence WASH factors (e.g. flooding and sea-level rise affect piped water usage). The influence of climate change dynamics on WASH factors can be negative or positive for cholera transmission (e.g. drought could increase pathogen desiccation but reduce rainwater harvesting). Identifying risk pathways helps policymakers focus on cholera risk mitigation, now and in the future.

The impact of climate change on Cholera: A review on the global status and future challenges

Water ecosystems can be rather sensitive to evolving or sudden changes in weather parameters. These changes can result in alterations in the natural habitat of pathogens, vectors, and human hosts, as well as in the transmission dynamics and geographic distribution of infectious agents. However, the interaction between climate change and infectious disease is rather complicated and not deeply understood. In this narrative review, we discuss climate-driven changes in the epidemiology of Vibrio species-associated diseases with an emphasis on cholera. Changes in environmental parameters do shape the epidemiology of Vibrio cholerae. Outbreaks of cholera cause significant disease burden, especially in developing countries. Improved sanitation systems, access to clean water, educational strategies, and vaccination campaigns can help control vibriosis. In addition, real-time assessment of climatic parameters with remote-sensing technologies in combination with robust surveillance systems could help detect environmental changes in high-risk areas and result in early public health interventions that can mitigate potential outbreaks.

How climate change can affect cholera incidence and prevalence? A systematic review

Although the number of cholera infection decreased universally, climate change can potentially affect both incidence and prevalence rates of disease in endemic regions. There is considerable consistent evidence, explaining the associations between cholera and climatic variables. However, it is essentially required to compare and interpret these relationships globally. The aim of the present study was to carry out a systematic review in order to identify and appraise the literature concerning the relationship between nonanthropogenic climatic variabilities such as extreme weather- and ocean-related variables and cholera infection rates. The systematic literature review of studies was conducted by using determined search terms via four major electronic databases (PubMed, Web of Science, Embase, and Scopus) according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach. This search focused on published articles in English-language up to December 31, 2018. A total of 43 full-text studies that met our criteria have been identified and included in our analysis. The reviewed studies demonstrated that cholera incidence is highly attributed to climatic variables, especially rainfall, temperature, sea surface temperature (SST) and El Niño Southern Oscillation (ENSO). The association between cholera incidence and climatic variables has been investigated by a variety of data analysis methodologies, most commonly time series analysis, generalized linear model (GLM), regression analysis, and spatial/GIS. The results of this study assist the policy-makers who provide the efforts for planning and prevention actions in the face of changing global climatic variables.

Climate change and Vibrio cholerae in Herring eggs: The role of indigenous communities in public health outbreak responses

The impacts of climate variability on cholera cases in Malaysia

Introduction: Altered weather patterns and changes in precipitation, temperature and humidity resulting from climate change could affect the distribution and incidence of cholera. This study is to quantify climate-induced increase in morbidity rates of cholera. Material and Methods: Monthly cholera cases and monthly temperature, precipitation, and relative humidity data from 2004 to 2014 were obtained from the Malaysian Ministry of Health and Malaysian Meteorological Department, respectively. Poisson generalized linear models were developed to quantify the relationship between meteorological parameters and the number of reported cholera cases. Results: The findings revealed that the total number of cholera cases in Malaysia during the 11 year study period was 3841 cases with 32 deaths. Out of these, 45.1% of the cases were among children below 12 years old and 75% of the cases were from Sabah. Temperature and precipitation gave significant impact on the cholera cases in Sabah, (p<0.001) while precipitation were significant in Terengganu (p<0.001), and Sarawak (p=0.013). Monthly lag temperature data at Lag 0, 1, and 2 months were associated with the cholera cases in Sabah (p<0.001). The change in odds of having cholera cases were by the factor of 3.5 for every 1 degrees C increase in temperature. However, the contribution of rainfall was very mild, whereby an increase of 1 mm in precipitation will increase the excess risk of cholera by up to 0.8%. Conclusion: This study concludes that climate does influence the number of cholera cases in Malaysia.

Successive epidemic waves of cholera in South Sudan between 2014 and 2017: A descriptive epidemiological study

BACKGROUND: Between 2014 and 2017, successive cholera epidemics occurred in South Sudan within the context of civil war, population displacement, flooding, and drought. We aim to describe the spatiotemporal and molecular features of the three distinct epidemic waves and explore the role of vaccination campaigns, precipitation, and population movement in shaping cholera spread in this complex setting. METHODS: In this descriptive epidemiological study, we analysed cholera linelist data to describe the spatiotemporal progression of the epidemics. We placed whole-genome sequence data from pandemic Vibrio cholerae collected throughout these epidemics into the global phylogenetic context. Using whole-genome sequence data in combination with other molecular attributes, we characterise the relatedness of strains circulating in each wave and the region. We investigated the association of rainfall and the instantaneous basic reproduction number using distributed lag non-linear models, compared county-level attack rates between those with early and late reactive vaccination campaigns, and explored the consistency of the spatial patterns of displacement and suspected cholera case reports. FINDINGS: The 2014 (6389 cases) and 2015 (1818 cases) cholera epidemics in South Sudan remained spatially limited whereas the 2016-17 epidemic (20?438 cases) spread among settlements along the Nile river. Initial cases of each epidemic were reported in or around Juba soon after the start of the rainy season, but we found no evidence that rainfall modulated transmission during each epidemic. All isolates analysed had similar genotypic and phenotypic characteristics, closely related to sequences from Uganda and Democratic Republic of the Congo. Large-scale population movements between counties of South Sudan with cholera outbreaks were consistent with the spatial distribution of cases. 21 of 26 vaccination campaigns occurred during or after the county-level epidemic peak. Counties vaccinated on or after the peak incidence week had 2·2 times (95% CI 2·1-2·3) higher attack rates than those where vaccination occurred before the peak. INTERPRETATION: Pandemic V cholerae of the same clonal origin was isolated throughout the study period despite interepidemic periods of no reported cases. Although the complex emergency in South Sudan probably shaped some of the observed spatial and temporal patterns of cases, the full scope of transmission determinants remains unclear. Timely and well targeted use of vaccines can reduce the burden of cholera; however, rapid vaccine deployment in complex emergencies remains challenging. FUNDING: The Bill & Melinda Gates Foundation.

Inland cholera in freshwater environs of north India

In the freshwater environment of north India, cholera appears seasonally in form of clusters as well as sporadically, accounting for a significant piece of the puzzle of cholera epidemiology. We describe a number of cholera outbreaks with an average attack rate of 96.5/1000 but an overall low case fatality (0.17). Clinical cholera cases coincided with high rainfall and elevated temperatures, whereas isolation of V. cholerae non-O1 non-O139 from water was dependent on temperature (p??0.05). However, isolation from plankton samples correlated with increased temperature and pH (p?

Cholera risk: A machine learning approach applied to essential climate variables

Oceanic and coastal ecosystems have undergone complex environmental changes in recent years, amid a context of climate change. These changes are also reflected in the dynamics of water-borne diseases as some of the causative agents of these illnesses are ubiquitous in the aquatic environment and their survival rates are impacted by changes in climatic conditions. Previous studies have established strong relationships between essential climate variables and the coastal distribution and seasonal dynamics of the bacteria Vibrio cholerae, pathogenic types of which are responsible for human cholera disease. In this study we provide a novel exploration of the potential of a machine learning approach to forecast environmental cholera risk in coastal India, home to more than 200 million inhabitants, utilising atmospheric, terrestrial and oceanic satellite-derived essential climate variables. A Random Forest classifier model is developed, trained and tested on a cholera outbreak dataset over the period 2010-2018 for districts along coastal India. The random forest classifier model has an Accuracy of 0.99, an F1 Score of 0.942 and a Sensitivity score of 0.895, meaning that 89.5% of outbreaks are correctly identified. Spatio-temporal patterns emerged in terms of the model’s performance based on seasons and coastal locations. Further analysis of the specific contribution of each Essential Climate Variable to the model outputs shows that chlorophyll-a concentration, sea surface salinity and land surface temperature are the strongest predictors of the cholera outbreaks in the dataset used. The study reveals promising potential of the use of random forest classifiers and remotely-sensed essential climate variables for the development of environmental cholera-risk applications. Further exploration of the present random forest model and associated essential climate variables is encouraged on cholera surveillance datasets in other coastal areas affected by the disease to determine the model’s transferability potential and applicative value for cholera forecasting systems.

UNDRR Hazard Information Profile: Cholera

Climate-sensitive infectious disease modelling software tools

Landscape mapping of software tools for climate-sensitive infectious disease modelling

Developing a forecasting model for cholera incidence in Dhaka megacity through time series climate data

Climate change and the spread of disease: An illustrative case of the first Australian invasive non-toxigenic Vibrio cholerae infection in a newborn

The effect of climate change on cholera disease: The road ahead using artificial neural network

Survey and genetic characterization of Vibrio cholerae in Apalachicola Bay, Florida (2012-2014)

Rapid forecasting of cholera risk in Mozambique: Translational challenges and opportunities

Post-monsoon waterlogging-associated upsurge of cholera cases in and around Kolkata metropolis, 2015

Outbreak of cholera due to Cyclone Kenneth in Northern Mozambique, 2019

Effects of large-scale oceanic phenomena on non-cholera vibriosis incidence in the United States: Implications for climate change

Analysis of factors contributing to the spread of cholera in developing countries

Rainfall as a driver of epidemic cholera: Comparative model assessments of the effect of intra-seasonal precipitation events

Near real-time forecasting for cholera decision making in Haiti after Hurricane Matthew

Mathematical modelling and numerical simulations of the influence of hygiene and seasons on the spread of cholera

Influences of heatwave, rainfall, and tree cover on cholera in Bangladesh

Increase in reported cholera cases in Haiti following Hurricane Matthew: An interrupted time series model

A new methodology for modelling of health risk from urban flooding exemplified by cholera – case Dhaka, Bangladesh

The complex interplay between everyday risks and disaster risks: The case of the 2014 cholera pandemic and 2015 flood disaster in Accra, Ghana

Seasonality in cholera dynamics: A rainfall-driven model explains the wide range of patterns in endemic areas

Natural disasters and cholera outbreaks: Current understanding and future outlook

Molecular epidemiology of cholera outbreaks during the rainy season in Mandalay, Myanmar

Healthcare waste management during disasters and its effects on climate change: Lessons from 2010 earthquake and cholera tragedies in Haiti

Evaluating the complex interactions between malaria and cholera prevalence, neglected tropical disease comorbidities, and community perception of health risks of climate change

El Nino and the shifting geography of cholera in Africa

Climate-driven endemic cholera is modulated by human mobility in a megacity

Climate variability and avian cholera transmission in Guangxi, China

Cholera – Management and prevention

Cholera forecast for Dhaka, Bangladesh, with the 2015-2016 El Nino: Lessons learned

Assessment of risk of cholera in Haiti following Hurricane Matthew

Vibrio cholerae non-O1, non-O139 bacteraemia associated with pneumonia, Italy 2016

Necrotizing fasciitis due to Vibrio cholerae non-O1/non-O139 after exposure to Austrian bathing sites

Molecular epidemiology of Vibrio cholerae associated with flood in Brahamputra River valley, Assam, India

El Nino, climate, and cholera associations in Piura, Peru, 1991-2001: A wavelet analysis

Cholera in Cameroon, 2000-2012: Spatial and temporal analysis at the operational (health district) and sub climate levels

Survey on antimicrobial resistance patterns in Vibrio vulnificus and Vibrio cholerae non-O1/non-O139 in Germany reveals carbapenemase-producing Vibrio cholerae in coastal waters

Satellite based assessment of hydroclimatic conditions related to cholera in Zimbabwe

Predictive time series analysis linking Bengal cholera with terrestrial water storage measured from gravity recovery and climate experiment sensors

Downscaling river discharge to assess the effects of climate change on cholera outbreaks in the Bengal Delta

Climate and socioeconomic influences on interannual variability of cholera in Nigeria

A global map of suitability for coastal Vibrio cholerae under current and future climate conditions

Genetic and phenotypic analysis of Vibrio cholerae non-O1, non-O139 isolated from German and Austrian patients

Cholera in the Lake Kivu region (DRC): Integrating remote sensing and spatially explicit epidemiological modeling

Cholera and shigellosis: Different epidemiology but similar responses to climate variability

A differential effect of Indian ocean dipole and El Nino on cholera dynamics in Bangladesh

Highly localized sensitivity to climate forcing drives endemic cholera in a megacity

Oral vaccines against cholera

Warming oceans, phytoplankton, and river discharge: Implications for cholera outbreaks

The costs of climate change: A study of cholera in Tanzania

Influence of relative humidity in Vibrio cholerae infection: A time series model

Climate variability and the outbreaks of cholera in Zanzibar, East Africa: A time series analysis

Cholera in Bangladesh: Climatic components of seasonal variation

Influence of temperature and rainfall on the evolution of cholera epidemics in Lusaka, Zambia, 2003-2006: Analysis of a time series

Impact of drainage networks on cholera outbreaks in Lusaka, Zambia

Impact of temperature variability on cholera incidence in southeastern Africa, 1971-2006

Effects of local climate variability on transmission dynamics of cholera in Matlab, Bangladesh

Climatic components of seasonal variation in cholera incidence

The effect of rainfall on the incidence of cholera in Bangladesh

Seasonality of cholera from 1974 to 2005: A review of global patterns

Prediction of epidemic cholera due to Vibrio cholerae O1 in children younger than 10 years using climate data in Bangladesh

Environmental signatures associated with cholera epidemics

Regional-scale climate-variability synchrony of cholera epidemics in West Africa

Climatic, socio-economic, and health factors affecting human vulnerability to cholera in the Lake Victoria basin, East Africa

Association between climate variability and hospital visits for non-cholera diarrhoea in Bangladesh: Effects and vulnerable groups

Hazard Information Profiles: Supplement to UNDRR-ISC Hazard Definition & Classification Review – Technical Report

Quality criteria for the evaluation of climate-informed early warning systems for infectious diseases

Predicting Climate Sensitive Infectious Diseases to Protect Public Health and Strengthen National Security

Management of A Cholera Epidemic

Ending Cholera – A global roadmap to 2030

Atlas of Health and Climate

Early detection, assessment and response to acute public health events: Implementation of Early Warning and Response with a focus on Event-Based Surveillance

WHO Cholera Outbreak Toolbox

UNICEF Cholera Toolkit

Surveillance and disease data for cholera

WHO Global Health Observatory