Browsing by Subject "Cholera"

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    Open Access
    gbpA as a Novel qPCR Target for the Species-Specific Detection of Vibrio cholerae O1, O139, Non-O1/Non-O139 in Environmental, Stool, and Historical Continuous Plankton Recorder Samples
    (Public Library of Science, 2015) Vezzulli, Luigi; Stauder, Monica; Grande, Chiara; Pezzati, Elisabetta; Verheye, Hans M.; Owens, Nicholas J. P.; Pruzzo, Carla
    The Vibrio cholerae N-acetyl glucosamine-binding protein A (GbpA) is a chitin-binding protein involved in V . cholerae attachment to environmental chitin surfaces and human intestinal cells. We previously investigated the distribution and genetic variations of gbpA in a large collection of V . cholerae strains and found that the gene is consistently present and highly conserved in this species. Primers and probe were designed from the gbpA sequence of V . cholerae and a new Taq-based qPCR protocol was developed for diagnostic detection and quantification of the bacterium in environmental and stool samples. In addition, the positions of primers targeting the gbpA gene region were selected to obtain a short amplified fragment of 206 bp and the protocol was optimized for the analysis of formalin-fixed samples, such as historical Continuous Plankton Recorder (CPR) samples. Overall, the method is sensitive (50 gene copies), highly specific for V . cholerae and failed to amplify strains of the closely-related species Vibrio mimicus . The sensitivity of the assay applied to environmental and stool samples spiked with V . cholerae ATCC 39315 was comparable to that of pure cultures and was of 10 2 genomic units/l for drinking and seawater samples, 10 1 genomic units/g for sediment and 10 2 genomic units/g for bivalve and stool samples. The method also performs well when tested on artificially formalin-fixed and degraded genomic samples and was able to amplify V . cholerae DNA in historical CPR samples, the earliest of which date back to August 1966. The detection of V . cholerae in CPR samples collected in cholera endemic areas such as the Benguela Current Large Marine Ecosystem (BCLME) is of particular significance and represents a proof of concept for the possible use of the CPR technology and the developed qPCR assay in cholera studies.
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    International Responses to Health Epidemics: An Analysis of Global Health Actors' Responses to Persistent Cholera Outbreaks in Harare, Zimbabwe.
    (2020) Nyaruwata, Chido; Scanlon, Helen
    Cholera is a diarrhoeal disease caused by the infection of the intestine with bacterium vibrio cholera. The diarrhoeal disease is a recurrent feature of Zimbabwe's post 1990s history. From 1993 to 2018, the country has experienced several cholera outbreaks in both rural and urban areas. The country's worst cholera outbreak occurred in 2008/2009 and resulted in over 4000 deaths. The dissertation analyses three global health actors' responses to persistent cholera outbreaks in Harare, the capital city of Zimbabwe. Building on previous scholarship of water, cholera and politics, the dissertation compares global health actors' responses to the 2008/2009 and September to November 2018 cholera outbreaks. The dissertation used the qualitative research method including analysis of existing academic literature, Zimbabwean national legislation, non-governmental organisation (NGO) publications and conference reports, news articles and Zimbabwean government policy documents. In-depth interviews with personnel from the World Health Organisation, United Nations Children's Fund, Médecins Sans Frontierès (Doctors without Borders) and the Harare City Council Health Department were conducted in Harare, Zimbabwe from June to July 2019. The dissertation demonstrates that the scope and speed of global health actors' emergency cholera interventions in Harare are shaped by Zimbabwe's political climate and the state of Harare's health, water and sanitation infrastructure.
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    Public perception of drinking water safety in South Africa 2002-2009: a repeated cross-sectional study
    (BioMed Central Ltd, 2012) Wright, Jim; Yang, Hong; Rivett, Ulrike; Gundry, Stephen
    BACKGROUND:In low and middle income countries, public perceptions of drinking water safety are relevant to promotion of household water treatment and to household choices over drinking water sources. However, most studies of this topic have been cross-sectional and not considered temporal variation in drinking water safety perceptions. The objective of this study is to explore trends in perceived drinking water safety in South Africa and its association with disease outbreaks, water supply and household characteristics. METHODS: This repeated cross-sectional study draws on General Household Surveys from 2002-2009, a series of annual nationally representative surveys of South African households, which include a question about perceived drinking water safety. Trends in responses to this question were examined from 2002-2009 in relation to reported cholera cases. The relationship between perceived drinking water safety and organoleptic qualities of drinking water, supply characteristics, and socio-economic and demographic household characteristics was explored in 2002 and 2008 using hierarchical stepwise logistic regression. RESULTS: The results suggest that perceived drinking water safety has remained relatively stable over time in South Africa, once the expansion of improved supplies is controlled for. A large cholera outbreak in 2000-02 had no apparent effect on public perception of drinking water safety in 2002. Perceived drinking water safety is primarily related to water taste, odour, and clarity rather than socio-economic or demographic characteristics. CONCLUSION: This suggests that household perceptions of drinking water safety in South Africa follow similar patterns to those observed in studies in developed countries. The stability over time in public perception of drinking water safety is particularly surprising, given the large cholera outbreak that took place at the start of this period.