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Mukhopadhyay AK, Takeda Y, Balakrish Nair G. Cholera outbreaks in the El Tor biotype era and the impact of the new El Tor variants. Curr Top Microbiol Immunol 2014; 379:17-47. [PMID: 24710767 DOI: 10.1007/82_2014_363] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Vibrio cholerae O1, the causative agent of the disease cholera, has two biotypes namely the classical and El Tor. Biotype is a subspecific taxonomic classification of V. cholerae O1. Differentiation of V. cholerae strains into biotype does not alter the clinical management of cholera but is of immense public health and epidemiological importance in identifying the source and spread of infection, particularly when V. cholerae is first isolated in a country or geographic area. From recorded history, till date, the world has experienced seven pandemics of cholera. Among these, the first six pandemics are believed to have been caused by the classical biotype whereas the ongoing seventh pandemic is caused by the El Tor biotype. In recent years, new pathogenic variants of V. cholerae have emerged and spread throughout many Asian and African countries with corresponding cryptic changes in the epidemiology of cholera. In this chapter, we describe the outbreaks during the seventh pandemic El Tor biotype era spanning more than five decades along with the recent advances in our understanding of the development, evolution, spread, and impact of the new variants of El Tor strains.
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Affiliation(s)
- Asish K Mukhopadhyay
- National Institute of Cholera and Enteric Diseases, P 33, CIT Road, Scheme XM, Beliaghata, Kolkata, 700010, India,
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You YA, Ali M, Kanungo S, Sah B, Manna B, Puri M, Nair GB, Bhattacharya SK, Convertino M, Deen JL, Lopez AL, Wierzba TF, Clemens J, Sur D. Risk map of cholera infection for vaccine deployment: the eastern Kolkata case. PLoS One 2013; 8:e71173. [PMID: 23936491 PMCID: PMC3732263 DOI: 10.1371/journal.pone.0071173] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/25/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Despite advancement of our knowledge, cholera remains a public health concern. During March-April 2010, a large cholera outbreak afflicted the eastern part of Kolkata, India. The quantification of importance of socio-environmental factors in the risk of cholera, and the calculation of the risk is fundamental for deploying vaccination strategies. Here we investigate socio-environmental characteristics between high and low risk areas as well as the potential impact of vaccination on the spatial occurrence of the disease. METHODS AND FINDINGS The study area comprised three wards of Kolkata Municipal Corporation. A mass cholera vaccination campaign was conducted in mid-2006 as the part of a clinical trial. Cholera cases and data of the trial to identify high risk areas for cholera were analyzed. We used a generalized additive model (GAM) to detect risk areas, and to evaluate the importance of socio-environmental characteristics between high and low risk areas. During the one-year pre-vaccination and two-year post-vaccination periods, 95 and 183 cholera cases were detected in 111,882 and 121,827 study participants, respectively. The GAM model predicts that high risk areas in the west part of the study area where the outbreak largely occurred. High risk areas in both periods were characterized by poor people, use of unsafe water, and proximity to canals used as the main drainage for rain and waste water. Cholera vaccine uptake was significantly lower in the high risk areas compared to low risk areas. CONCLUSION The study shows that even a parsimonious model like GAM predicts high risk areas where cholera outbreaks largely occurred. This is useful for indicating where interventions would be effective in controlling the disease risk. Data showed that vaccination decreased the risk of infection. Overall, the GAM-based risk map is useful for policymakers, especially those from countries where cholera remains to be endemic with periodic outbreaks.
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Affiliation(s)
- Young Ae You
- International Vaccine Institute, Seoul, Republic of Korea
| | - Mohammad Ali
- International Vaccine Institute, Seoul, Republic of Korea
| | - Suman Kanungo
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Binod Sah
- International Vaccine Institute, Seoul, Republic of Korea
| | - Byomkesh Manna
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Mahesh Puri
- International Vaccine Institute, Seoul, Republic of Korea
| | | | - Sujit Kumar Bhattacharya
- National Institute of Cholera and Enteric Diseases, Kolkata, India
- Indian Council of Medical Research, New Delhi, India
| | - Matteo Convertino
- HumNat Lab, Department of Biological Systems Engineering, Virginia Tech, Blacksburg, Virginia, United States of America
- Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Institute for Critical Technology and Applied Science, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Jacqueline L. Deen
- Menzies School of Health Research, Casuarina, Northern Territory, Australia
| | - Anna Lena Lopez
- International Vaccine Institute, Seoul, Republic of Korea
- University of the Philippines Manila, National Institutes of Health, Manila, Philippines
| | | | - John Clemens
- International Vaccine Institute, Seoul, Republic of Korea
- University of California Los Angeles, School of Public Health, Los Angeles, United States of America
| | - Dipika Sur
- National Institute of Cholera and Enteric Diseases, Kolkata, India
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Cabral JPS. Water microbiology. Bacterial pathogens and water. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2010; 7:3657-703. [PMID: 21139855 PMCID: PMC2996186 DOI: 10.3390/ijerph7103657] [Citation(s) in RCA: 415] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 09/07/2010] [Accepted: 09/28/2010] [Indexed: 02/07/2023]
Abstract
Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.
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Affiliation(s)
- João P S Cabral
- Center for Interdisciplinary Marine and Environmental Research (C. I. I. M. A. R.), Faculty of Sciences, Oporto University, Rua do Campo Alegre, 4169-007 Oporto, Portugal.
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Carrel M, Emch M, Streatfield PK, Yunus M. Spatio-temporal clustering of cholera: the impact of flood control in Matlab, Bangladesh, 1983-2003. Health Place 2009; 15:741-52. [PMID: 19217821 DOI: 10.1016/j.healthplace.2008.12.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 11/14/2008] [Accepted: 12/20/2008] [Indexed: 10/21/2022]
Abstract
Introducing flood control to an area of endemic waterborne diseases could have significant impacts on spatio-temporal occurrence of cholera. Using 21-year data from Bangladesh, we conducted cluster analysis to explore changes in spatial and temporal distribution of cholera incidence since the construction of flood control structures. Striking changes in temporal cluster patterns emerged, including a shift from dry-season to rainy-season clusters following flood protection and delayed clustering inside the protected areas. Spatial differences in pre-flood protection and post-protection cholera clusters are weaker. Changes in spatio-temporal cholera clustering, associated with implementation of flood protection strategies, could affect local cholera prevention efforts.
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Affiliation(s)
- Margaret Carrel
- Department of Geography, University of North Carolina, Chapel Hill, NC 27599, USA.
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Association of Vibrio cholerae O1 El Tor and O139 Bengal with the Copepods Acartia tonsa and Eurytemora affinis. Appl Environ Microbiol 2007; 73:7926-33. [PMID: 17951440 DOI: 10.1128/aem.01238-07] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The association of Vibrio cholerae with zooplankton has been suggested as an important factor in transmission of human epidemic cholera, and the ability to colonize zooplankton surfaces may play a role in the temporal variation and predominance of the two different serogroups (V. cholerae O1 El Tor and O139) in the aquatic environment. To date, interactions between specific serogroups and species of plankton remain poorly understood. Laboratory microcosm experiments were carried out to compare quantitatively the colonization of two copepod species, Acartia tonsa and Eurytemora affinis, by each of the epidemic serogroups. V. cholerae O1 consistently achieved higher abundances than V. cholerae O139 in colonizing adults of each copepod species as well as the multiple life stages of E. affinis. This difference in colonization may be significant in the general predominance of V. cholerae O1 in cholera epidemics in rural Bangladesh where water supplies are taken directly from the environment.
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Singer RS, Ward MP, Maldonado G. Can landscape ecology untangle the complexity of antibiotic resistance? Nat Rev Microbiol 2006; 4:943-52. [PMID: 17109031 DOI: 10.1038/nrmicro1553] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bacterial resistance to antibiotics continues to pose a serious threat to human and animal health. Given the considerable spatial and temporal heterogeneity in the distribution of resistance and the factors that affect its evolution, dissemination and persistence, we argue that antibiotic resistance must be viewed as an ecological problem. A fundamental difficulty in assessing the causal relationship between antibiotic use and resistance is the confounding influence of geography: the co-localization of resistant bacterial species with antibiotic use does not necessarily imply causation and could represent the presence of environmental conditions and factors that have independently contributed to the occurrence of resistance. Here, we show how landscape ecology, which links the biotic and abiotic factors of an ecosystem, might help to untangle the complexity of antibiotic resistance and improve the interpretation of ecological studies.
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Affiliation(s)
- Randall S Singer
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55455 USA.
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Zaman K, Yunus M, Arifeen SE, Baqui AH, Sack DA, Hossain S, Rahim Z, Ali M, Banu S, Islam MA, Begum N, Begum V, Breiman RF, Black RE. Prevalence of sputum smear-positive tuberculosis in a rural area in Bangladesh. Epidemiol Infect 2006; 134:1052-9. [PMID: 16569271 PMCID: PMC2870495 DOI: 10.1017/s0950268806006108] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2006] [Indexed: 11/07/2022] Open
Abstract
The objective of the study was to determine the prevalence of smear-positive tuberculosis (TB) in a rural area in Bangladesh at Matlab. A TB surveillance system was established among 106,000 people in rural Bangladesh at Matlab. Trained field workers interviewed all persons aged > or = 15 years to detect suspected cases of TB (cough > 21 days) and sputum specimens of suspected cases were examined for acid-fast bacilli (AFB). Of 59,395 persons interviewed, 4235 (7.1%) had a cough for > 21 days. Sputum specimens were examined for AFB from 3834 persons, 52 (1.4%) of them were positive for AFB. The prevalence of chronic cough and sputum positivity were significantly higher among males compared to females (P < 0.001). The population-based prevalence rate of smear-positive TB cases was 95/100,000 among persons aged > or = 15 years. Cases of TB clustered geographically (relative risk 5.53, 95% CI 3.19-9.59). The high burden of TB among rural population warrants appropriate measures to control TB in Bangladesh. The higher prevalence of persistent cough and AFB-positive sputum among males need further exploration. Factors responsible for higher prevalence of TB in clusters should be investigated.
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Affiliation(s)
- K Zaman
- ICDDR,B, Centre for Health and Population Research, Dhaka, Bangladesh.
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