Epidemiology & Ecology of Vibrio Cholerae in Bangladesh

描述（由申请人提供）：霍乱仍然是整个发展中世界的一个主要公共卫生问题。最初申请的主要目的是检验涉及地表水的环境因素是观测到的霍乱周期性和大流行性质的原因这一假设。所收集的数据有力地表明，但不能证明，环境因素可预测霍乱暴发。现在的工作重点将是进一步确定所发现的积极环境关联，并通过遗传方法确定从环境中分离出的霍乱弧菌菌株与从患者身上分离出的霍乱弧菌菌株的相关性。将与卫生与人口研究中心、马里兰大学生物技术研究所和医学院以及埃默里大学合作，继续在孟加拉国开展工作。将继续在两个霍乱暴发频繁的原址和一个新的第三个址（桑德班斯）进行双周临床和环境监测。桑德班斯是靠近孟加拉湾的红树林沼泽地区，也是1992年O139弧菌进入孟加拉国的地点。改进的化验将侧重于：(1)在地表水中鉴定和培养霍乱弧菌，使用标准技术和带有非放射性DNA探针的结肠印迹法（针对霍乱弧菌种类，O1、O139、ctx和tcpA）进行DNA提取和PCR；(2)通过基因分型（使用AFLP、ERIC-PCR和MLST）评估临床和环境分离株之间的关系；(3)鉴定和列举附着在特定浮游动物物种上的霍乱弧菌；采用直接荧光抗体技术和荧光原位杂交技术。利用监测数据，我们的霍乱传播模型将进一步完善。这将有助于预测霍乱的爆发，不仅在孟加拉国，而且在具有类似水生环境的其他国家，从而能够及早动员预防和治疗措施。孟加拉国在提供进行这类研究的环境方面是独一无二的。

DESCRIPTION (provided by applicant): Cholera continues to be a major public health problem throughout the developing world. The primary objective of the original application was to test the hypothesis that environmental factors involving surface waters were responsible for the observed periodicity and pandemic nature of cholera. Data collected strongly suggest, but do not prove, that environmental factors are predictive of cholera outbreaks. Work will now focus on further defining the positive environmental associations that were found, and in determining, by genetic methodology, the relatedness of V. cholerae strains isolated from the environment and those from patients. Work will continue in Bangladesh in association with the Centre for Health and Population Research (ICDDR, B), the University of Maryland Biotechnology Institute and School of Medicine, and Emory University. Bi-weekly clinical and environmental surveillance will continue at two of the original sites where cholera outbreaks were frequent and in a new third site (Sunderbans), an area of mangrove swamps close to the Bay of Bengal, the site of entry for the O139 vibrios in Bangladesh in 1992 Improved assays will focus on: (1) identifying and culturing V. cholerae in surface waters, using both standard techniques and colonly blots with non-radioactive DNA probes, (for V. cholerae species, O1, O139, ctx, and tcpA) DNA extraction, and PCR, (2) assessing the relationship between clinical and environmental isolates by genotyping (using AFLP, ERIC-PCR, and MLST) and (3) identifying and enumerating V. cholerae attached to specific zooplankton species, using direct fluorescent antibody techniques and fluorescent in situ hybridization assays. Using the surveillance data our model of cholera transmission will be further refined. This will be useful in predicting outbreaks of cholera, not only in Bangladesh, but also in other countries with similar aquatic environments, thereby allowing early mobilization of preventive and treatment measures. Bangladesh is unique in affording the environment for doing these types of studies.