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Penitentiary systems serve as breeding grounds for all kinds of diseases. Drawing upon new archival materials, this article examines the history of the management and reporting of epidemics in the Russian prison system from the late Imperial period to the present day. We use the case studies of cholera (1892-1893), typhus (1932-1933), and pulmonary tuberculosis (the 1990s) to examine how the general political and social conjuncture at different times affected the response of prison authorities to epidemics to show that, notwithstanding major shifts in society and polity, there was continuity in the management of epidemics by prison authorities in the long twentieth century. However, there were fundamental discrepancies in the way late Imperial, Soviet, and post-Soviet Russia reported epidemiological emergencies in prisons. We argue that Russia's tumultuous past has reinforced the tendency among the Russian penal administration towards a lack of transparency that has persisted to the present day, in relation to the latest, COVID-19, epidemic., (© The Author(s) 2023. Published by Oxford University Press.)

Epidemics of a wide variety of infectious diseases were constantly recorded in Russia. Asian cholera occupied a special place among epidemic diseases. In 1892, cholera was imported into the Russian Empire through the Black Sea ports, which reached the territory of the Kuban region by the summer of the same year. In 1892, about 300 thousand people died of cholera in Russia. They still did not know how to treat this terrible disease, did not know its mechanism of spread, as well as the peculiarities of its course. The article, prepared on the basis of an analysis of documentary data from the Archive Department of the administration of the municipal formation of the city of Novorossiysk and the archival Department of the Administration of the municipal formation of the Mostovsky district, examines the cholera epidemic that swept the territories of the Kuban region in 1892 and 1910. The authors characterize the main factors that contributed to the rapid spread of infection and assess the measures that were taken to combat the disease: the implementation of anti-cholera measures organized by the authorities was greatly hampered by the lack of education, prejudices and superstitions of the vast majority of the population; representatives of the nonresident population not only did not comply with basic standards of personal hygiene, but also expressed distrust, and sometimes and hostility towards doctors. Using archival data, the authors investigate the impact of infectious diseases on the demographic indicators of these settlements.

Since the onset of the seventh cholera pandemic, Ethiopia has been affected by recurrent epidemics. However, the epidemiology of cholera in this country remains poorly understood. This study aimed to describe cholera outbreak characteristics in Ethiopia from 2015 to 2021. During this period, Ethiopia experienced four epidemic waves. The first wave involved nationwide outbreaks during the second half of 2016 followed by outbreaks predominantly affecting Somali Region in 2017. The second wave primarily affected Tigray and Afar Regions. During the third wave, multiple smaller-scale outbreaks occurred during 2019. The fourth wave was limited to Bale Zone (Oromia Region) in 2021. Overall, a north to south shift was observed over the course of the study period. Major cholera transmission factors included limited access to safe water and sanitation facilities. Severe weather events (drought and flooding) appear to aggravate cholera diffusion. Cholera transmission between Ethiopia and nearby countries (Kenya and Somalia), likely plays a major role in regional cholera dynamics. Overall, this study provides the first understanding of recent spatiotemporal cholera dynamics in Ethiopia to inform cholera control and elimination strategies., (© 2024. The Author(s).)

Cholera continues to be a global health threat. Understanding how cholera spreads between locations is fundamental to the rational, evidence-based design of intervention and control efforts. Traditionally, cholera transmission models have used cholera case-count data. More recently, whole-genome sequence data have qualitatively described cholera transmission. Integrating these data streams may provide much more accurate models of cholera spread; however, no systematic analyses have been performed so far to compare traditional case-count models to the phylodynamic models from genomic data for cholera transmission. Here, we use high-fidelity case-count and whole-genome sequencing data from the 1991 to 1998 cholera epidemic in Argentina to directly compare the epidemiological model parameters estimated from these two data sources. We find that phylodynamic methods applied to cholera genomics data provide comparable estimates that are in line with established methods. Our methodology represents a critical step in building a framework for integrating case-count and genomic data sources for cholera epidemiology and other bacterial pathogens.

The 2030 Global Task Force on Cholera Control Roadmap hinges on strengthening the implementation of multistranded cholera interventions, including community engagement and health system strengthening. However, a composite picture of specific facilitators and barriers for these interventions and any overlapping factors existing between the two, is lacking. Therefore, this study aims to address this shortcoming, focusing on cholera-reporting countries, which are disproportionately affected by cholera and may be cholera endemic. A scoping methodology was chosen to allow for iterative mapping, synthesis of the available research and to pinpoint research activity for global and local cholera policy-makers and shareholders. Using the Arksey and O'Malley framework for scoping reviews, we searched PubMed, Web of Science and CINAHL. Inclusion criteria included publication in English between 1990 and 2021 and cholera as the primary document focus in an epidemic or endemic setting. Data charting was completed through narrative descriptive and thematic analysis. Forty-four documents were included, with half relating to sub-Saharan African countries, 68% (30/44) to cholera endemic settings and 21% (9/44) to insecure settings. We identified four themes of facilitators and barriers to health systems strengthening: health system cooperation and agreement with external actors; maintaining functional capacity in the face of change; good governance, focused political will and sociopolitical influences on the cholera response and insecurity and targeted destruction. Community engagement had two themes: trust building in the health system and growing social cohesion. Insecurity and the community; cooperation and agreement; and sociopolitical influences on trust building were themes of factors acting at the interface between community engagement and health system. Given the decisive role of the community-health system interface for both sustained health system strengthening and community engagement, there is a need to advocate for conflict resolution, trust building and good governance for long-term cholera prevention and control in cholera reporting countries., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Cholera remains a major public health problem that threatens human health worldwide and its severity is continuing. In this paper, an edge-based model for cholera transmission on random networks is proposed and investigated. The model assumes that two communities share a common water source and includes three transmission routes, namely intra- and inter-community human-to-human transmission as well as water-to-human transmission. Intra-community human-to-human contacts are modeled through a random contact network, while both inter-community and water-to-human transmission are modeled through external nodes that reach each individual in the network to the same extent. The basic reproduction number and the equations of the final epidemic size are obtained. In addition, our study considers the cholera situation in Banadir, which is one of the most severely infected regions in Somalia, during the period (2019-2021). According to the geographical location, two adjacent districts are selected and our model fits well with the real data on the monthly cumulative cholera cases of these two districts during the above-mentioned period. From the perspective of network topology, cutting off high-risk contacts by supervising, isolating, quarantining and closing places with high-degree cholera-infected individuals to reduce degree heterogeneity is an effective measure to control cholera transmission. Our findings might offer some useful insights on cholera control., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Infectious diseases continue to pose a significant threat to the health of humans globally. While the spread of pathogens transcends geographical boundaries, the management of infectious diseases typically occurs within distinct spatial units, determined by geopolitical boundaries. The allocation of management resources within and across regions (the "governance structure") can affect epidemiological outcomes considerably, and policy-makers are often confronted with a choice between applying control measures uniformly or differentially across regions. Here, we investigate the extent to which uniform and non-uniform governance structures affect the costs of an infectious disease outbreak in two-patch systems using an optimal control framework. A uniform policy implements control measures with the same time varying rate functions across both patches, while these measures are allowed to differ between the patches in a non-uniform policy. We compare results from two systems of differential equations representing transmission of cholera and Ebola, respectively, to understand the interplay between transmission mode, governance structure and the optimal control of outbreaks. In our case studies, the governance structure has a meaningful impact on the allocation of resources and burden of cases, although the difference in total costs is minimal. Understanding how governance structure affects both the optimal control functions and epidemiological outcomes is crucial for the effective management of infectious diseases going forward., (© 2023. The Author(s).)

Cholera, a severe gastrointestinal infection caused by the bacterium Vibrio cholerae , remains a major threat to public health, with a yearly estimated global burden of 2.9 million cases. Although most existing models for the disease focus on its population dynamics, the disease evolves from within-host processes to the population, making it imperative to link the multiple scales of the disease to gain better perspectives on its spread and control. In this study, we propose an immuno-epidemiological model that links the between-host and within-host dynamics of cholera. The immunological (within-host) model depicts the interaction of the cholera pathogen with the adaptive immune response. We distinguish pathogen dynamics from immune response dynamics by assigning different time scales. Through a time-scale analysis, we characterise a single infected person by their immune response. Contrary to other within-host models, this modelling approach allows for recovery through pathogen clearance after a finite time. Then, we scale up the dynamics of the infected person to construct an epidemic model, where the infected population is structured by individual immunological dynamics. We derive the basic reproduction number ($ \mathcal{R}&#95;0 $) and analyse the stability of the equilibrium points. At the disease-free equilibrium, the disease will either be eradicated if $ \mathcal{R}&#95;0 < 1 $ or otherwise persists. A unique endemic equilibrium exists when $ \mathcal{R}&#95;0 > 1 $ and is locally asymptotically stable without a loss of immunity.

This paper provides an analysis of Andrija Štampar's activities after World War II on the establishment of effective international health. Analyzed archival materials have confirmed with numerous evidence that Štampar as the president of the Interim Commission of the World Health Organization (WHO) played a crucial role in the establishment of the ideological starting points and organization of the WHO system, which remain relevant to date. Apart from the strategic foundations, it has been shown that his principles regarding the need for practical action based on the best professional knowledge and experience have no alternatives. The above is presented in the paper with the details of Štampar's activities during the cholera epidemic in Egypt and associated with the experiences of the recent global crisis caused by the COVID pandemic.

The war in Syria, which started over 11 years ago, has devastated the country's water sources, healthcare system, and other vital facilities for healthy living. The country is vulnerable to outbreaks, especially epidemic-prone ones like cholera, due to its fragile health system. Syria experienced its last hit of cholera in 2009, which led to the deaths of several Syrian children and affected about 1,000 people. The current cholera resurgence in Syria calls for public concern. Considering the poor access to clean water, the forced relocation of people, and other destruction caused by the war, these factors have exposed Syrian children to infectious diseases like cholera. We argued for more efforts toward the implementation of Water, Sanitation and Hygiene (WASH) in the country. We also pointed out the need for proper education and sensitization campaigns using all available resources to educate the populace, mass chlorination of wells, mapping vulnerable areas, and implementing WASH while encouraging vaccination coverage for cholera as a strategy to reduce its incidence. Improving the national surveillance systems will aid in the timely and appropriate reporting of any outbreak. Again, more negotiations should be done to seek a lasting solution to ending the war and restoring peace and serenity in the country., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Eneh, Admad, Nazir, Onukansi, Oluwatobi, Innocent and Ojo.)

Background: Enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae O1 are most common bacterial causes of diarrheal diseases in Bangladesh. This analysis projected distribution of ETEC and V. cholerae O1 among diarrheal patients of icddr,b, Dhaka hospital in two diarrheal peaks of 2022., Methodology: Under the 2% systematic surveillance system, stool samples collected from diarrheal patients of icddr,b hospital were cultured and diagnostic testing was done for ETEC and V. cholerae O1. Comparison of positive cases was done between first peak (March-April) and second peak (October-November) in 2022., Results: A total of 2,937 stool specimens were tested of which 12% were ETEC and 20% were V. cholerae O1. About 40% of the severe dehydration cases were infected with V. cholerae O1. Predominant ETEC enterotoxin type was 'LT/ST' (41%). The LT enterotoxin significantly increased from 13% to 28% in the second peak ( p  = 0.015). The predominant colonization factors (CFs) on ETEC were CS5 + CS6 (23%), followed by CS6 (15%). CF-positive isolates was significantly higher in the second peak (36%) than in the first peak (22%) ( p  = 0.043). Total 14% cases were co-infected with ETEC and V. cholerae O1. Significant differences in the distribution of enterotoxin types were observed ( p  = 0.029) among the co-infection cases., Conclusion: Changing patterns of enterotoxin and CFs observed in ETEC pathogens should be taken into consideration for ETEC vaccine development. Considering cholera and ETEC biannual trends in causing diarrheal epidemics and outbreaks, emphasizes the need for thoughts on combination vaccine strategies for preventing acute watery diarrhea due to the two major bacterial pathogens., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Tauheed, Ahmed, Akter, Firoj, Ahmmed, Rahman, Afrad, Islam, Rahman, Khan, Alam, Bhuiyan, Chowdhury and Qadri.)

The cholera epidemic that hit Haiti from October 2010 to February 2019 was the world's deadliest of the last 25 years. Officially, the successive waves caused 9789 deaths, although numerous additional casualties could not be recorded. The origin of this epidemic has been the subject of a controversy involving two opposing theories. The first hypothesis, put forward by renowned American academics, was that the cholera epidemic originated from the environment, due to the proliferation and transmission of aquatic Vibrio cholerae bacteria driven by a confluence of circumstances, i.e., the earthquake followed by a hot summer and, ultimately, heavy rainfall and flooding. The alternative hypothesis, which was subsequently confirmed by epidemiological and genomic studies, attributed the epidemic to the recent importation of cholera by UN peacekeepers recently arrived from Nepal, and to a river polluted with sewage. In late 2016, the Secretary General of the United Nations finally begged the Haitian people for forgiveness. This implicit recognition of the role of the UN in the cholera epidemic helped to fund the ongoing fight against it. Case-area targeted interventions aimed at interrupting cholera transmission were reinforced, which resulted in the extinction of the epidemic within two years. In the meantime, several phylogenetic studies on Vibrio cholerae during the seventh cholera pandemic demonstrated that local environmental and global epidemic Vibrio populations were distinct. These studies also showed that epidemics arose when the bacterium had diversified and that it had spread during transmission events associated with human travel., Competing Interests: Disclosure of Competing Interest The authors declare that they have no conflicts of interest, (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

In 2010 following a catastrophic earthquake, Haiti saw the beginning of what would become the world's largest cholera epidemic. Nepalese United Nations peacekeepers were later implicated as the source of cholera. Our research examines Haitian community beliefs and perceptions, six-and-a-half years after the outbreak began, regarding the origin of Haiti's cholera outbreak. A narrative capture tool was used to record micronarratives of Haitian participants surrounding ten United Nations bases across Haiti. Seventy-seven micronarratives focused on cholera were selected for qualitative analysis from a larger dataset. Three themes emerged: who introduced cholera to Haiti, how cholera was introduced to Haiti, and preventative measures against cholera. With varying levels of confidence, the origins of the epidemic were conceptualised as directly resulting from the actions of the United Nations and Nepalese peacekeepers, exhibiting a distrust of foreign intervention in Haiti and frustration with inadequate water and sanitation infrastructure that facilitated widespread transmission of cholera. This study reinforces the need for additional transparent communication from the UN to address ongoing misconceptions surrounding the cholera outbreak, action to clean water and sanitation practices in Haiti, and for the voices of Haitian citizens to be heard and included in reforming foreign aid delivery in the country.

In 2010, Haiti experienced one of the deadliest cholera outbreaks of the 21st century. United Nations (UN) peacekeepers are widely believed to have introduced cholera, and the UN has formally apologized to Haitians and accepted responsibility. The current analysis examines how Haitian community members experienced the epidemic and documents their attitudes around accountability. Using SenseMaker, Haitian research assistants collected micronarratives surrounding 10 UN bases in Haiti. Seventy-seven cholera-focused micronarratives were selected for a qualitative thematic analysis. The five following major themes were identified: (1) Cholera cases and deaths; (2) Accessing care and services; (3) Protests and riots against the UN; (4) Compensation; and (5) Anti-colonialism. Findings highlight fear, frustration, anger, and the devastating impact that cholera had on families and communities, which was sometimes compounded by an inability to access life-saving medical care. Most participants believed that the UN should compensate cholera victims through direct financial assistance but there was significant misinformation about the UN's response. In conclusion, Haiti's cholera victims and their families deserve transparent communication and appropriate remedies from the UN. To rebuild trust in the UN and foreign aid, adequate remedies must be provided in consultation with victims.

More than a decade ago Singer (2009) described Gibraltar's experience with cholera and smallpox in 1865 as a syndemic. In this study, we provide a reassessment of that event and, consequently, propose a methodology to identify a syndemic at the population level. We propose that the concept of the harvesting effect from demographic studies on crisis mortality provides a useful framework for evaluating the presence of a syndemic. Our research begins by establishing a normative baseline mortality (BM) through life table analysis, where changes in life expectancy (LE) around BM can be used to show a distinctive pattern of significant decline and increase. Such was the case with the presence of both cholera and smallpox in the fall of 1865, when LE fell significantly to 19.64 years from the background LE of 32.88 years. A year later, this decline was followed by a significant increase in LE to 41.34 years. Excessive mortality followed by a fallow (healthy) period represents a signature feature of a syndemic driven by a short-term infectious disease epidemic. The presence of both cholera and smallpox in 1860 did not produce similar results, evidence which suggests that the presence of two infectious epidemics in an impoverished population was not sufficient to produce a syndemic. The presence of a protracted state of quarantine, with its concomitant social and economic consequences, was a driving force responsible for amplifying the disease burden in 1865, and elevating to a syndemic status. Multivariate Poisson regression revealed patio level limiting factors (such as, presence of a cistern, a well, a live-in servant, and a Jewish co-resident), as well as risk factors (such as, a smallpox death in the building; the presence of a foreign-born individual). From the two-phase assessment of the syndemic in Gibraltar, we developed a conceptual framework for identifying, contributing, driving, and limiting factors., (Crown Copyright © 2020. Published by Elsevier Ltd. All rights reserved.)

This study examined the spatial effects of El Niño and vulnerability on cholera in Peru across the epidemic period of 1991 to 1998. Using Wavelet and GIS analyses, relationships between sea surface temperatures and department-level cholera rates were estimated. In addition, we constructed composite indices to assess spatial vulnerability during the 1997-98 extreme El Niño. The findings demonstrated strong temporal connections in 1997-98, most evident in northern Peru, and less clear connections from 1991-93. Spatially, we found patterns of difference, greater cholera risk in northern coastal Peru in 1997-98, compared to greater risk in central and southern coastal Peru in 1991-92. Overall, the spatial vulnerability analysis suggested preexisting social conditions and disaster impacts increased cholera exposure and infection in 1998. Our study supports the notion that the spatial nature of El Niño's impacts on cholera rates exacerbated cholera vulnerability following the emergence, rather than triggered the epidemic's onset in 1991., (Copyright © 2021. Published by Elsevier Ltd.)

The Global Task Force on Cholera Control (GTFCC) created a strategy for early outbreak detection, hotspot identification, and resource mobilization coordination in response to the Yemeni cholera epidemic. This strategy requires a systematic approach for defining and classifying outbreak signatures, or the profile of an epidemic curve and its features. We used publicly available data to quantify outbreak features of the ongoing cholera epidemic in Yemen and clustered governorates using an adaptive time series methodology. We characterized outbreak signatures and identified clusters using a weekly time series of cholera rates in 20 Yemeni governorates and nationally from 4 September 2016 through 29 December 2019 as reported by the World Health Organization (WHO). We quantified critical points and periods using Kolmogorov-Zurbenko adaptive filter methodology. We assigned governorates into six clusters sharing similar outbreak signatures, according to similarities in critical points, critical periods, and the magnitude of peak rates. We identified four national outbreak waves beginning on 12 September 2016, 6 March 2017, 28 May 2018, and 28 January 2019. Among six identified clusters, we classified a core regional hotspot in Sana'a, Sana'a City, and Al-Hudaydah-the expected origin of the national outbreak. The five additional clusters differed in Wave 2 and Wave 3 peak frequency, timing, magnitude, and geographic location. As of 29 December 2019, no governorates had returned to pre-Wave 1 levels. The detected similarity in outbreak signatures suggests potentially shared environmental and human-made drivers of infection; the heterogeneity in outbreak signatures implies the potential traveling waves outwards from the core regional hotspot that could be governed by factors that deserve further investigation.

Background: Cholera outbreaks in western Democratic Republic of the Congo (DRC) are thought to be primarily the result of westward spread of cases from the Great Lakes Region. However, other patterns of spatial spread in this part of the country should not be excluded. The aim of this study was to explore alternative routes of spatial spread in western DRC., Methods: A literature review was conducted to reconstruct major outbreak expansions of cholera in western DRC since its introduction in 1973. We also collected data on cholera cases reported at the health zone (HZ) scale by the national surveillance system during 2000-2018. Based on data from routine disease surveillance, we identified two subperiods (week 45, 2012-week 42, 2013 and week 40, 2017-week 52, 2018) for which the retrospective space-time permutation scan statistic was implemented to detect spatiotemporal clusters of cholera cases and then to infer the spread patterns in western DRC other than that described in the literature., Results: Beyond westward and cross-border spread in the West Congo Basin from the Great Lakes Region, other dynamics of cholera epidemic propagation were observed from neighboring countries, such as Angola, to non-endemic provinces of southwestern DRC. Space-time clustering analyses sequentially detected clusters of cholera cases from southwestern DRC to the northern provinces, demonstrating a downstream-to-upstream spread along the Congo River., Conclusions: The spread of cholera in western DRC is not one-sided. There are other patterns of spatial spread, including a propagation from downstream to upstream areas along the Congo River, to be considered as preferential trajectories of cholera in western DRC., (© 2021. The Author(s).)

It was in 1907 when Korea was annexed by Japan in the field of health care systems as the Gwangje Hospital, Uihakgyo the National Medical School and the Korean Red Cross Hospital were merged into the colonial Daehan Hospital, and massive cholera epidemic controls by the Japanese Army were enforced. However, despite their importance, the cholera epidemic of 1907 in Korea and preventive measures taken at that time have not yet been studied extensively as a single research subject. The purpose of this paper is to contribute to a more concrete and broader understanding of the Korea-Japan annexation of health care systems under the rule of the Japanese Resident-General of Korea by revealing new facts and correcting existing errors. In 1907, cholera was transmitted to Korea from China and Japan and spread across the Korean Peninsula, resulting in a major public health crisis, perhaps one of the most serious cholera outbreaks in the twentieth century Korea. Although Busan and Pyeongyang were the cities most infected with cholera, the targets for the most intensive interventions were Gyeongseong (Seoul) and Incheon, where the Japanese Crown Prince were supposed to make a visit. The Japanese police commissioner took several anti-cholera preventive measures in Gyeongseong, including searching out patients, disinfecting and blocking infected areas, and isolating the confirmed or suspected. Nevertheless, cholera was about to be rampant especially among Japanese residents. In this situation, Itō Hirobumi, the first Resident-General of Korea, organized the temporary cholera control headquarters to push ahead the visit of the Japanese Crown Prince for his political purposes to colonize Korea. To dispel Emperor Meiji's concerns, Itō had to appoint Satō Susumu, the famous Japanese Army Surgeon General, as an advisor, since he had much credit at Court. In addition, as the Japanese-led Korean police lacked epidemic control ability and experience, the headquarters became an improvised organization commanded by the Japanese Army in Korea and wielded great influence on the formation of the colonial disease control systems. Its activities were forced, violent, and negligent, and many Korean people were quite uncooperative in some anti-cholera measures. As a result, the Japanese Army in Korea took the initiative away from the Korean police in epidemic controls, serving the heavy-handed military policy of early colonial period. In short, the cholera epidemic and its control in 1907 were important events that shaped the direction of Japan's colonial rule.

Background: Temperature and precipitation are known to affect Vibrio cholerae outbreaks. Despite this, the impact of drought on outbreaks has been largely understudied. Africa is both drought and cholera prone and more research is needed in Africa to understand cholera dynamics in relation to drought., Methods: Here, we analyse a range of environmental and socioeconomic covariates and fit generalised linear models to publicly available national data, to test for associations with several indices of drought and make cholera outbreak projections to 2070 under three scenarios of global change, reflecting varying trajectories of CO 2 emissions, socio-economic development, and population growth., Results: The best-fit model implies that drought is a significant risk factor for African cholera outbreaks, alongside positive effects of population, temperature and poverty and a negative effect of freshwater withdrawal. The projections show that following stringent emissions pathways and expanding sustainable development may reduce cholera outbreak occurrence in Africa, although these changes were spatially heterogeneous., Conclusions: Despite an effect of drought in explaining recent cholera outbreaks, future projections highlighted the potential for sustainable development gains to offset drought-related impacts on cholera risk. Future work should build on this research investigating the impacts of drought on cholera on a finer spatial scale and potential non-linear relationships, especially in high-burden countries which saw little cholera change in the scenario analysis., (© 2021. The Author(s).)

Cholera remains a heavy burden worldwide, especially in Sub-Saharan African countries, which account for the majority of the reported cases on the continent. In this study, a 27-year retrospective analysis of cholera epidemics in Guinea-Bissau was performed in order to highlight major stressors fueling the trigger and dissemination of the disease. Although the role of environmental factors did not always have the same degree of importance for the onset of epidemics, a cholera seasonal pattern was clearly perceived, with most of the reported cases occurring during the wet season. The generated theoretical hypothesis indicated rainfall above climatological average, associated with a lack of WASH (water, sanitation and hygiene) infrastructure, and the occurrence of concomitant epidemics in neighboring countries as the key indicators for optimal conditions for cholera to thrive in Guinea-Bissau. Warmer air temperature, the increase in sea surface temperature, and the decrease in salinity in the coastal areas may also contribute to the emergence and/or aggravation of cholera events. Prediction of the conditions favorable for cholera growth and identification of risk pathways will allow the timely allocation of resources, and support the development of alert tools and mitigation strategies.

Cholera, an acute diarrheal disease, is caused by pathogenic strains of Vibrio cholerae generated by the lysogenization of the filamentous cholera toxin phage CTXΦ. Although CTXΦ phage in the classical biotype are usually integrated solitarily or with a truncated copy, those in El Tor biotypes are generally found in tandem and/or with related genetic elements. Due to this structural difference in the CTXΦ prophage array, the prophage in the classical biotype strains does not yield extrachromosomal CTXΦ DNA and does not produce virions, whereas the El Tor biotype strains can replicate the CTXΦ genome and secrete infectious CTXΦ phage particles. However, information on the CTXΦ prophage array structure of pathogenic V. cholerae is limited. Therefore, we investigated the complete genomic sequences of five clinical V. cholerae isolates obtained in Kolkata (India) during 2007 to 2011. The analysis revealed that recent isolates possessed an altered CTXΦ prophage array of the prototype El Tor strain. These strains were defective in replicating the CTXΦ genome. All recent isolates possessed identical rstA and intergenic sequence 1 (Ig-1) sequences and comparable rstA expression in the prototype El Tor strain, suggesting that the altered CTXΦ array was responsible for the defective replication of the prophage. Therefore, CTXΦ structures available in the database and literatures can be classified as replicative and nonreplicative. Furthermore, V. cholerae epidemic strains became capable of producing CTXΦ phage particles since the 1970s. However, V. cholerae epidemic strains again lost the capacity for CTXΦ production around the year 2010, suggesting that a significant change in the dissemination pattern of the current cholera pandemic occurred. IMPORTANCE Cholera is an acute diarrheal disease caused by pathogenic strains of V. cholerae generated by lysogenization of the filamentous cholera toxin phage CTXΦ. The analysis revealed that recent isolates possessed altered CTXΦ prophage array of prototype El Tor strain and were defective in replicating the CTXΦ genome. Classification of CTXΦ structures in isolated years suggested that V. cholerae epidemic strains became capable of producing CTXΦ phage particles since the 1970s. However, V. cholerae epidemic strains again lost the capacity for CTXΦ production around the year 2010, suggesting that a critical change had occurred in the dissemination pattern of the current cholera pandemic.

Seasonal variation affects the dynamics of many infectious diseases including influenza, cholera and malaria. The time when infectious individuals are first introduced into a population is crucial in predicting whether a major disease outbreak occurs. In this investigation, we apply a time-nonhomogeneous stochastic process for a cholera epidemic with seasonal periodicity and a multitype branching process approximation to obtain an analytical estimate for the probability of an outbreak. In particular, an analytic estimate of the probability of disease extinction is shown to satisfy a system of ordinary differential equations which follows from the backward Kolmogorov differential equation. An explicit expression for the mean (resp. variance) of the first extinction time given an extinction occurs is derived based on the analytic estimate for the extinction probability. Our results indicate that the probability of a disease outbreak, and mean and standard derivation of the first time to disease extinction are periodic in time and depend on the time when the infectious individuals or free-living pathogens are introduced. Numerical simulations are then carried out to validate the analytical predictions using two examples of the general cholera model. At the end, the developed theoretical results are extended to more general models of infectious diseases.

Centre Department, Haiti, was the origin of a major cholera epidemic during 2010-2019. Although no fine-scale spatial delineation is officially available, we aimed to analyze determinants of cholera at the local level and identify priority localities in need of interventions. After estimating the likely boundaries of 1,730 localities by using Voronoi polygons, we mapped 5,322 suspected cholera cases reported during January 2015-September 2016 by locality alongside environmental and socioeconomic variables. A hierarchical clustering on principal components highlighted 2 classes with high cholera risk: localities close to rivers and unimproved water sources (standardized incidence ratio 1.71, 95% CI 1.02-2.87; p = 0.04) and urban localities with markets (standardized incidence ratio 1.69, 95% CI 1.25-2.29; p = 0.0006). Our analyses helped identify and characterize areas where efforts should be focused to reduce vulnerability to cholera and other waterborne diseases; these methods could be used in other contexts.

Background: Cholera epidemics continue to challenge disease control, particularly in fragile and conflict-affected states. Rapid detection and response to small cholera clusters is key for efficient control before an epidemic propagates. To understand the capacity for early response in fragile states, we investigated delays in outbreak detection, investigation, response, and laboratory confirmation, and we estimated epidemic sizes. We assessed predictors of delays, and annual changes in response time., Methods: We compiled a list of cholera outbreaks in fragile and conflict-affected states from 2008 to 2019. We searched for peer-reviewed articles and epidemiological reports. We evaluated delays from the dates of symptom onset of the primary case, and the earliest dates of outbreak detection, investigation, response, and confirmation. Information on how the outbreak was alerted was summarized. A branching process model was used to estimate epidemic size at each delay. Regression models were used to investigate the association between predictors and delays to response., Results: Seventy-six outbreaks from 34 countries were included. Median delays spanned 1-2 weeks: from symptom onset of the primary case to presentation at the health facility (5 days, IQR 5-5), detection (5 days, IQR 5-6), investigation (7 days, IQR 5.8-13.3), response (10 days, IQR 7-18), and confirmation (11 days, IQR 7-16). In the model simulation, the median delay to response (10 days) with 3 seed cases led to a median epidemic size of 12 cases (upper range, 47) and 8% of outbreaks ≥ 20 cases (increasing to 32% with a 30-day delay to response). Increased outbreak size at detection (10 seed cases) and a 10-day median delay to response resulted in an epidemic size of 34 cases (upper range 67 cases) and < 1% of outbreaks < 20 cases. We estimated an annual global decrease in delay to response of 5.2% (95% CI 0.5-9.6, p = 0.03). Outbreaks signaled by immediate alerts were associated with a reduction in delay to response of 39.3% (95% CI 5.7-61.0, p = 0.03)., Conclusions: From 2008 to 2019, median delays from symptom onset of the primary case to case presentation and to response were 5 days and 10 days, respectively. Our model simulations suggest that depending on the outbreak size (3 versus 10 seed cases), in 8 to 99% of scenarios, a 10-day delay to response would result in large clusters that would be difficult to contain. Improving the delay to response involves rethinking the integration at local levels of event-based detection, rapid diagnostic testing for cluster validation, and integrated alert, investigation, and response.

Rugao and Haian belonging to First Branch of Su-Wan Liberated Area found fulminant cholera in 1946. The fulminant cholera spread throughout the Su-Wan Liberated Area in a short period of time. Thus, local mass and military led by CPC actively launched the Movement of Epidemic Prevention. They took some actions to clear up the circumstance, eliminate the pathogen, prevent the food contamination and cut off the route of transmission. Vaccination was carried out on a large scale. As a result of these measure, the fulminant cholera was efficiently controlled.

Background: Cholera is endemic in the Islamic Republic of Iran. According to surveillance system records and historical documents, cholera epidemics have led to thousands of deaths throughout the country in past centuries., Aims: The aim of this study was an overview of cholera disease during the last 5 decades (1965-2014) and the epidemiological features of the most recent large-scale outbreaks., Methods: In this descriptive study, cholera incidence data provided by the National Surveillance Database were extracted and significant fluctuating trends for 1965-2014 were tested using the Cochran-Armitage test. To identify the factors most associated with cholera incidence in the outbreaks, adjusted odds ratios were computed by ordinal logistic regression., Results: Analysis of data has shown a tremendous decrease in incidence trends, from 19.7/100 000 to 0.01/100 000 over the 9 cholera epidemics that occurred at 5-6 year intervals during 1965-2014. Younger age groups (15-44 years) and inhabitants in urban areas have been more vulnerable to cholera in recent epidemics. The virulence of the pathogen and the case fatality rates have not changed during the last 3 epidemics., Conclusion: The burden of cholera in terms of case load has dramatically reduced during 1965-2014. Furthermore, the epidemiological feature of cholera with regard to transmission route, domicile, age, immigration, mortality and antimicrobial resistance has changed considerably in recent epidemics. While the number of epidemic regions has diminished, some areas are still susceptible to cholera outbreaks., (Copyright © World Health Organization (WHO) 2020. Open Access. Some rights reserved. This work is available under the CC BY-NC-SA 3.0 IGO license (https://creativecommons.org/licenses/by-nc-sa/3.0/igo).)

In the past two centuries, several fatal infectious outbreaks have arisen in Iran. Presented here is a brief historical account of four fatal epidemics including cholera, plague, Spanish influenza of 1918 and smallpox between1796 and 1979. The lessons from these outbreaks could be helpful for better combatting other deadly epidemics including the present-day disastrous COVID-19 pandemic., (© 2020 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.)

Yemen has been faced with the worst cholera epidemic of modern times, with more than 1 million suspected cases and 3000 deaths at the time of writing. This problem is largely due to the longstanding civil war between pro-government forces and the Houthi armed movement, which has severely damaged already vulnerable sanitation and healthcare facilities and systems in the country. It is further compounded by a dire lack of basic amenities, chronic malnutrition, and unfavourable weather conditions. Another contributory component may be aerial transfer by cholera-infected chironomid insects. To contain the spread of cholera in Yemen, a nation-wide armistice should be negotiated, and national and local committees must be convened to coordinate efforts on the ground. Community isolation facilities with proper sanitation, reliable disposal systems, and a clean water supply should be set up to isolate and treat sick patients. The continuity of vaccination programmes should be ensured. Public health campaigns to educate local communities about good hygiene practices and nutrition are also necessary. The One Health paradigm emphasizes a multi-sectoral and transdisciplinary understanding and approach to prevent and mitigate the threat of communicable diseases. This paradigm is highly applicable to the ongoing cholera crisis in Yemen, as it demands a holistic and whole-of-society approach at the local, regional, and national levels. The key stakeholders and warring parties in Yemen must work towards a lasting ceasefire during these trying times, especially given the extra burden from the mounting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak worldwide.

Cholera reached the Maltese Archipelago for the first time ever in June 1837. It found a poor and destitute population that was not prepared for the epidemic. Many doctors feared contagion while others believed it was contracted from bad air or miasma. The first cases of cholera in Malta broke out at a hospital for the elderly and the infirm, the Ospizio in Floriana on 9th June 1837, reached a peak in the week between 12 July to 18 July and dwindled by the end of August 1837. The epidemic saw a death toll of 4252 from 8785 registered cholera cases when the Maltese population was 120,000. Contemporary foreign residents on the islands witnessed and recorded stories of heartlessness and harshness of terrified people. This degenerative behaviour, however, did not reach the callousness of rioting and murder that were observed in other countries. Also, during this dark time, there were people who showed compassion, kindness and selfless devotion to the sick and the dying. In the chaos that reigned during that summer, the inhabitants of one small town in the north of Malta organized themselves better than the rest with good results.

In 1886, cholera was prevalent nationwide in Joseon. This year was not yet the time when the Joseon government officially overhauled quarantine rules to go into effect. Thus, quarantine efforts to prevent cholera varied depending on each of the three opening ports in the Joseon Dynasty. In Wonsan, officials of the three countries(Joseon, Japan and Qing) discussed ways to deal with cholera, and quarantine activities were carried out smoothly. On the other hand, Busan underwent friction and conflict between the parties over the implementation of quarantine rules within the region. When the Japanese consulate said that it would establish quarantine rules first and implement them, officials from various countries, including the Joseon Dynasty, strongly protested against the movement, saying that they did not reach prior consent. On top of that, economic interests were also affecting circumstances of port trade. In Incheon, there were differences between the home country and the local consulate over the urgent issue to be dealt with locally and the legal principles of applying the treaty. Since consular officials were not authorized to establish quarantine rules, the situation was settled into cancellation of the rules already issued there. The Japanese consul working at each port in the Joseon Dynasty suggested specific rules to develop quarantine activities. At this point, we can read Japan's intention to preempt the standard of future quarantine inspections. The enforcement of quarantine rules, however, was a matter that required consent from the Joseon official Gamri, the Acting Commissioner of the Joseon Maritime Customs and diplomats from each country. Furthermore, they had to go through the process of obtaining review and approval from their home countries if there were any problems in the operation of the treaty. The establishment and implementation of quarantine rules were complicated by interests of various players in each country concerning protection of their own citizens. Even though it was timely and the purpose of implementation was good, it could not follow through the quarantine rules as proposed by the Japanese consul at the opening port. The accumulation of quarantine experience and information at each port of Joseon in 1886 provided the foundation for the Joseon government to move toward to establish quarantine rules and implement them with the consent of each country in the following year.

The environmental reservoir of Vibrio cholerae, the causative agent of cholera, has been a topic of scientific investigation ever since the discovery of the bacterium itself. While the bacteria can be isolated from both clinical and environmental sources during epidemics, it evades isolation by conventional culture techniques during the period between successive epidemics. The problem is identifying the location and mode of survival and multiplication of V. cholerae during this inter-epidemic period. This information is crucial not only for epidemiological reasons, but also because the seasonality of cholera epidemics is plausibly mediated by the climate-regulated activity of the reservoir. This article focuses on the epidemiological importance of the environmental reservoir of V. cholerae, considering several investigations made on different types of aquatic fauna (zooplanktons, crustaceans, etc.) and flora (macrophytes and microphytes). After evaluating different lines of evidence, we make the case that certain species of cyanobacteria (Anabaena variabilis, Microcystis aeruginosa) can act as inter-epidemic reservoirs of V. cholerae. Physiological and functional aspects of this association are also discussed. We then present a hypothesis, expanding upon a previously published conceptual model, of how the climate-regulated seasonality of cholera epidemics is mediated by the effect of climatic factors on algal bloom and other local abiotic variables in the water, using Bangladesh as a model. Finally, another aspect of the climate-dependence of disease patterns is briefly explored: large-scale environmental signatures associated with cholera, and recent modelling efforts to predict cholera outbreaks based on coastal phytoplankton. The review, therefore, serves not only as a study of the identity of the inter-epidemic reservoir of V. cholerae, but also explores different ways in which the reservoir and the pathogen behaviour is affected by the climate, and the possible consequences it may have on disease pattern., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Outbreaks of cholera in Africa seem to be unrelenting which has been continuous and recurrent leading to high morbidity and mortality in some quarters., Objective: The objective of this narrative review is to investigate and identify factors responsible for the recurrent outbreaks of cholera in Africa and response strategies that have been employed in curbing the problem, with the view of aggregating otherwise sparing data needed for policy formulation geared towards control and eradication of the disease., Methods: Search of literatures indexed in Google Scholar, PubMed and AJOL databases was carried out. Sixty-five eligible articles with reports on the risk factors that drive recurrent outbreaks, endemicity and response strategies were analyzed., Results: Our findings indicate that continuous and recurrent outbreaks of cholera in Africa are fueled by cross-border migration, environmental reservoirs, socioeconomic factors, climate change and political instability. The review also identified specific response strategies and modelling approaches that have helped in containing and reducing the impact of these outbreaks., Conclusion: Paying attention and tackling these identified factors that are dependent and independent can help put an end to this running battle.

Combining the official cholera line list data and outbreak investigation reports from the ministries of health in Uganda and South Sudan with molecular analysis of Vibrio cholerae strains revealed the interrelatedness of the epidemics in both countries in 2014. These results highlight the need for collaboration to control cross-border outbreaks.

Waterborne diseases have a tremendous influence on human life. The contaminated drinking water causes water-borne disease like cholera. Pulse vaccination is an important and effective strategy for the elimination of infectious diseases. A waterborne disease like cholera can also be controlled by using impulse technique. In this paper, we have proposed a delayed SEIRB epidemic model with impulsive vaccination and disinfection. We have studied the pulse vaccination strategy and sanitation to control the cholera disease. The existence and stability of the disease-free and endemic periodic solution are investigated both analytically and numerically. It is shown that there exists an infection-free periodic solution, using the impulsive dynamical system defined by the stroboscopic map. It is observed that the infection-free periodic solution is globally attractive when the impulse period is less than some critical value. From the analysis of the model, we have obtained a sufficient condition for the permanence of the epidemic with pulse vaccination. The main highlight of this paper is to introduce impulse technique along with latent period into the SEIRB epidemic model to investigate the role of pulse vaccination and disinfection on the dynamics of the cholera epidemics., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Although cholera is considered the quintessential long-cycle waterborne disease, studies have emphasized the existence of short-cycle (food, household) transmission. We investigated singular Danish cholera epidemics (in 1853) to elucidate epidemiological parameters and modes of spread., Methods: Using time series data from cities with different water systems, we estimated the intrinsic transmissibility (R0). Accessing cause-specific mortality data, we studied clinical severity and age-specific impact. From physicians' narratives we established transmission chains and estimated serial intervals., Results: Epidemics were seeded by travelers from cholera-affected cities; initial transmission chains involving household members and caretakers ensued. Cholera killed 3.4%-8.9% of the populations, with highest mortality among seniors (16%) and lowest in children (2.7%). Transmissibility (R0) was 1.7-2.6 and the serial interval was estimated at 3.7 days (95% confidence interval, 2.9-4.7 days). The case fatality ratio (CFR) was high (54%-68%); using R0 we computed an adjusted CFR of 4%-5%., Conclusions: Short-cycle transmission was likely critical to early secondary transmission in historic Danish towns. The outbreaks resembled the contemporary Haiti outbreak with respect to transmissibility, age patterns, and CFR, suggesting a role for broader hygiene/sanitation interventions to control contemporary outbreaks., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Cholera is an infectious disease that in the epidemic form should not continue to appear now, as is known from the experience of developed countries, Aim: The aim of this work is to bring to memory the epidemics of cholera, that were introduced to the territory of Poland, in the past and the role of National Institute of Hygiene (PZH) in the fight against them and to demonstrate contemporary danger from cholera outbreaks that still exists in the world, Material and Methods: The information from the historic publications were analyzed, the results Polish research performed in National Institute of Hygiene in the second half of the XX century were collected and demonstrated the most recent information from in the world science publications on the subject of cholera and the conditions that were in the origin of the recent outbreaks of cholera mentioned, Results: The data available for the number of cholera victims in the epidemics of XIX century is concerning the persons ill with characteristic clinical symptoms, but the data for XX century is concerning only patients that were infected with by the strain Vibrio cholerae O1 classic type, the bacteria that were described by R. Koch, but from the 70-years of XX century mostly the cases infected with Vibrio cholerae O1 type El-Tor, that was the etiologic agent of the seventh cholera pandemic, Summary and Conclusions: The origin of the epidemic cholera is depending on several conditions :appearance in water the infectious agent with the toxin producing character, ecological conditions of the surface waters, and on living conditions of human society which might be infected from the source of infection in water. The presence of the infectious agent in the natural waters should be always taken under special consideration car any worsening of living condition of the human population like natural disaster or war, may still create the dangers of the epidemic of infectious disease, as recently has happened with the outbreak of epidemic of cholera in Yemen

Objective: Point-of-use (POU) strategies to improve drinking water, particularly chlorination, are promoted within cholera epidemics when centrally delivered safe drinking water is lacking. Most studies examining POU practices during cholera epidemics have relied on single cross-sectional studies which are limited for assessing behavioural changes. This study examined POU practices in a community over time during a cholera outbreak., Study Design: Secondary data analysis of existing dataset., Methods: During attendance at well-baby clinics serving a low-income peri-urban community in the Dominican Republic, mothers had been routinely asked, using a structured questionnaire, about POU strategies used for drinking water for their children. Frequency distribution of reported practices was determined over a 21 month period during the cholera outbreak on the island of Hispaniola., Results: An estimated 27.8% of children were reported to have had some exposure to untreated tap water. Unsustained reductions in exposure to untreated tap water were noted early in the epidemic. POU chlorination was infrequent and showed no significant or sustained increases over the study time period., Conclusion: High reliance on bottled water, consistent with national household patterns prior to the cholera outbreak, may have reduced the perceived need for POU chlorination. Examination of the safety of relying on bottled water during cholera outbreaks is needed. Additionally, further inquiries are needed to understand variation in POU practices both during and beyond cholera outbreaks., (Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.)

Cholera is an epidemic diarrheal disease transmitted through the digestive tract; it can cause obstetric complications in pregnant women. The objective of this study was to describe the epidemiological, clinical, and therapeutic aspects of cholera in pregnant women, as well as its course, during the 2012 epidemic in Conakry. This retrospective, descriptive studied examined the records of this epidemic over a 7-month period (from May 15 to December 15, 2012). Of 2,808 cholera patients at our hospital, 80 were pregnant, that is, 2.85%. Their mean age was 30 years [range: 15-45 years], 94% were from Conakry (94%), and 69% were in the third trimester of pregnancy. Choleriform diarrhea and vomiting were the main signs, found respectively in 100% and 95% of the women; dehydration was mild for 16%, moderate for 45%, and severe for 39%. Support consisted of rehydration, by plans A (16%), B (45%) or C (39%) and antibiotic treatment based on erythromycin (85%), doxycycline (14%), or azithromycin (1%). Other drugs that were used included phloroglucinol-trimethylphloroglucinol (Spasfon(®)) for 45%, acetaminophen for 65%, and iron/folic acid for 1% of cases. The major obstetric complications were 4 intrauterine deaths (5%), 2 cases of threatened abortion (2%), 1 preterm delivery (1%), and 1 maternal death. The cholera outbreak in 2012 affected a large number of pregnant women in Conakry, most during their third trimester. The classic clinical manifestations were associated with obstetric complications and maternal-fetal risks.

Background: Cholera is caused by Vibrio cholerae, and is transmitted through fecal-oral contact. Infection occurs after the ingestion of the bacteria and is usually asymptomatic. In a minority of cases, it causes acute diarrhea and vomiting, which can lead to potentially fatal severe dehydration, especially in the absence of appropriate medical care. Immunity occurs after infection and typically lasts 6-36 months. Cholera is responsible for outbreaks in many African and Asian developing countries, and caused localised and episodic epidemics in South America until the early 1990s. Haiti, despite its low socioeconomic status and poor sanitation, had never reported cholera before the recent outbreak that started in October 2010, with over 720,000 cases and over 8700 deaths (Case fatality rate: 1.2%) through 8 december 2014. So far, this outbreak has seen 3 epidemic peaks, and it is expected that cholera will remain in Haiti for some time., Methodology/findings: To trace the path of the early epidemic and to identify hot spots and potential transmission hubs during peaks, we examined the spatial distribution of cholera patients during the first two peaks in Artibonite, the second-most populous department of Haiti. We extracted the geographic origin of 84,000 patients treated in local health facilities between October 2010 and December 2011 and mapped these addresses to 63 rural communal sections and 9 urban cities. Spatial and cluster analysis showed that during the first peak, cholera spread along the Artibonite River and the main roads, and sub-communal attack rates ranged from 0.1% to 10.7%. During the second peak, remote mountain areas were most affected, although sometimes to very different degrees even in closely neighboring locations. Sub-communal attack rates during the second peak ranged from 0.2% to 13.7%. The relative risks at the sub-communal level during the second phase showed an inverse pattern compared to the first phase., Conclusion/significance: These findings demonstrate the value of high-resolution mapping for pinpointing locations most affected by cholera, and in the future could help prioritize the places in need of interventions such as improvement of sanitation and vaccination. The findings also describe spatio-temporal transmission patterns of the epidemic in a cholera-naïve country such as Haiti. By identifying transmission hubs, it is possible to target prevention strategies that, over time, could reduce transmission of the disease and eventually eliminate cholera in Haiti., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)

The 2010 cholera epidemic in Haiti was one of the largest cholera epidemics ever recorded. To estimate the magnitude of the death toll during the first wave of the epidemic, we retrospectively conducted surveys at 4 sites in the northern part of Haiti. Overall, 70,903 participants were included; at all sites, the crude mortality rates (19.1-35.4 deaths/1,000 person-years) were higher than the expected baseline mortality rate for Haiti (9 deaths/1,000 person-years). This finding represents an excess of 3,406 deaths (2.9-fold increase) for the 4.4% of the Haiti population covered by these surveys, suggesting a substantially higher cholera mortality rate than previously reported.

A reaction-diffusion system modeling cholera epidemic in a non-homogeneously mixed population is introduced. The interaction between population and toxigenic Vibrio cholerae concentration in contaminated water has been taken into account. The existence of biologically meaningful equilibria is investigated together with their linear and nonlinear stability. Using the data collected during the Haiti cholera epidemic, a numerical simulation is performed.

Presence of Vibrio cholerae serogroups O1 and O139 in the waters of the rural area of Matlab, Bangladesh, was investigated with quantitative measurements performed with a portable flow cytometer. The relevance of this work relates to the testing of a field-adapted measurement protocol that might prove useful for cholera epidemic surveillance and for validation of mathematical models. Water samples were collected from different water bodies that constitute the hydrological system of the region, a well-known endemic area for cholera. Water was retrieved from ponds, river waters, and irrigation canals during an inter-epidemic time period. Each sample was filtered and analysed with a flow cytometer for a fast determination of V. cholerae cells contained in those environments. More specifically, samples were treated with O1- and O139-specific antibodies, which allowed precise flow-cytometry-based concentration measurements. Both serogroups were present in the environmental waters with a consistent dominance of V. cholerae O1. These results extend earlier studies where V. cholerae O1 and O139 were mostly detected during times of cholera epidemics using standard culturing techniques. Furthermore, our results confirm that an important fraction of the ponds' host populations of V. cholerae are able to self-sustain even when cholera cases are scarce. Those contaminated ponds may constitute a natural reservoir for cholera endemicity in the Matlab region. Correlations of V. cholerae concentrations with environmental factors and the spatial distribution of V. cholerae populations are also discussed.

Objective: To assess the antibiotic resistance and molecular characterization of cholera strains and to provide basis for clinical treatment and prevention of cholera., Methods: 4 stains isolated from an outbreak of cholera epidemic in Huai'an City in Jiangsu province in September 2010 were characterized using antibiotic susceptibility, biotype analysis, virluence genes detection, ctxB gene sequencing, and PFGE analysis., Results: The 4 strains were all resistant to sulphamethoxazole/trimethoprim, erythromycin, streptomycin. High drug susceptibility of the samples was found to 6 kinds of antibiotics such as amikacin, norfloxacin, ciprofloxacin, gentamicin, chloramphenicol, ampicillin. The isolates expressed phenotypic traits of both serogroup O1 ogawa and El Tor and carried 9 kinds of virulence genes, ctxA, ace, zot, toxR, tcpI, ompU, rtxC, tcpA, and hlyA gene. They were also identified as harboring the classical ctxB genotype based on amino acid residue substitutions. The PFGE profiles of NotI showed a single banding pattern, while SfiI's was 2 banding patterns., Conclusion: The bacterium type of Vibrio cholerae causing the epidemic outbreak of cholera belonged to the atypical EL Tor variant which was also identified as toxicogenic strain. The mapping of the strains prompted that there should be the common contamination source. Drug sensitivity test can guide the clinical drug use, in order to reduce the emergence of resistant strains.

Reactive vaccination has recently been adopted as an outbreak response tool for cholera and other infectious diseases. Owing to the global shortage of oral cholera vaccine, health officials must quickly decide who and where to distribute limited vaccine. Targeted vaccination in transmission hotspots (i.e. areas with high transmission efficiency) may be a potential approach to efficiently allocate vaccine, however its effectiveness will likely be context-dependent. We compared strategies for allocating vaccine across multiple areas with heterogeneous transmission efficiency. We constructed metapopulation models of a cholera-like disease and compared simulated epidemics where: vaccine is targeted at areas of high or low transmission efficiency, where vaccine is distributed across the population, and where no vaccine is used. We find that connectivity between populations, transmission efficiency, vaccination timing and the amount of vaccine available all shape the performance of different allocation strategies. In highly connected settings (e.g. cities) when vaccinating early in the epidemic, targeting limited vaccine at transmission hotspots is often optimal. Once vaccination is delayed, targeting the hotspot is rarely optimal, and strategies that either spread vaccine between areas or those targeted at non-hotspots will avert more cases. Although hotspots may be an intuitive outbreak control target, we show that, in many situations, the hotspot-epidemic proceeds so fast that hotspot-targeted reactive vaccination will prevent relatively few cases, and vaccination shared across areas where transmission can be sustained is often best.