Epidemiology and Ecology of Cholera in Africa

非洲霍乱的流行病学和生态学

• 批准号: 9903199
• 负责人: DAVID A SACK
• 金额: $ 67.2万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9903199
• 关键词: Africa; African; Area; Bacteriophages; Baltimore; Bangladesh; Behavioral; Cameroon; Case Fatality Rates; Case-Control Studies; Chad; Characteristics; Cholera; Climate; Clinical; Collaborations; Communities; Country; Detection; Disease Outbreaks; Ecology; Environmental Risk Factor; Epidemic; Epidemiology; Etiology; Event; Florida; Geography; Goals; Haiti; Health; Hospitals; Hot Spot; Household; Human; Institutes; Locales; Lytic; Maps; Maryland; Methods; Minisatellite Repeats; Molecular; Molecular Epidemiology; Monitor; Mozambique; Nature; Neighborhoods; Oral; Patients; Pattern; Prospective Studies; Public Health; Readiness; Research; Risk; Risk Factors; Rural; Sanitation; Schedule; Source; South Sudan; Tanzania; Testing; Thinness; Time; Trust; Uganda; Universities; Vibrio; Vibrio cholerae; Vibrio cholerae O1; Water; Zambia; base; care seeking; case control; epidemiology study; genome sequencing; high risk; improved; indexing; innovation; migration; pandemic disease; prevent; resistance mechanism; response; rural area; therapy development; transmission process; urban area; urban setting; water sampling; weather patterns; whole genome

PROJECT SUMMARY This project will describe the differing epidemiological and ecological patterns of cholera in two “hotspot” regions near the great lakes of Tanzania and Cameroon to understand the nature of cholera emergence and transmission in these areas of Africa. Our group has described cholera’s epidemiology and ecology in Bangladesh where cholera follows a predictable annual schedule. V. cholerae, both culturable and non-culturable forms can be detected in the ponds of Bangladesh, suggesting that vibrios from environmental reservoirs directly infect humans, leading to fecal-oral transmission and seasonal outbreaks. The seasonality in Bangladesh indicates climatic factors to be a major determinant for initiating and / or accelerating these outbreaks. In contrast to this consistent pattern in Bangladesh, African cholera outbreaks are much less predictable and they differ between countries. Cholera “hotspots” occur around the great lakes of Tanzania and Cameroon. For example, in Cameroon, severe outbreaks occur every few years with high case fatality rates, but cases are not detected during intervening lean periods. Similarly, Tanzania has outbreaks sporadically. Working with the Tanzanian Health Ministry, using molecular methods from recent outbreaks, we could differentiate localized outbreaks from other more widely disseminated outbreaks which were associated with continued spread. Similarly, in Cameroon, an outbreak in one region could be traced as it moved to the Lake Chad region. The study will conduct clinical and environmental surveillance for culturable and non-culturable V. cholerae in two regions of Tanzania (Dar es Salaam and surrounding areas and rural Kigoma) and the Far North Region of Cameroon. We will characterize the V. cholerae isolates and lytic vibriophage from cholera patients seeking care at hospital as well as community contacts to compare strains from index cases with those from nearby water sources and neighbors. These will also be compared to strains from other areas in Africa. Ecological surveillance will be used to associate transmission with the presence of lytic vibriophage, weather patterns; and water characteristics. Thus, this proposal will describe the molecular epidemiology and ecology of cholera in Tanzania and Cameroon to improve our understanding of transmission patterns of cholera across large areas of Africa, including factors that limit transmission. The research will evaluate outbreaks in which cholera emerges as a localized outbreak with limited transmission, or alternatively, results from widely transmitted introductions across borders. By providing a more complete understanding of factors, including vibriophage, leading to cholera’s emergence into epidemics, as well as their collapse, the project will guide the development of interventions to control cholera in Africa.

项目概要 该项目将描述两个“热点地区”霍乱的不同流行病学和生态模式 坦桑尼亚和喀麦隆大湖附近地区了解霍乱出现的性质和 非洲这些地区的传播。 我们的小组描述了孟加拉国霍乱的流行病学和生态学，那里的霍乱遵循 可预测的年度计划。霍乱弧菌，无论是可培养的还是不可培养的形式都可以在 孟加拉国的池塘，表明来自环境水库的弧菌直接感染人类，导致 粪口传播和季节性爆发。孟加拉国的季节性表明气候因素 引发和/或加速这些爆发的主要决定因素。 与孟加拉国的这种一贯模式相反，非洲霍乱疫情的可预测性要低得多，而且 它们因国家而异。霍乱“热点”发生在坦桑尼亚和喀麦隆的大湖周围。 例如，在喀麦隆，每隔几年就会发生一次严重的疫情，病死率很高，但病例数 在中间的稀薄时期没有检测到。同样，坦桑尼亚也有零星疫情爆发。与 坦桑尼亚卫生部利用最近爆发的分子方法，我们可以区分局部地区 与持续传播有关的其他更广泛传播的疫情的爆发。 同样，在喀麦隆，当某个地区的疫情转移到乍得湖地区时，就可以追踪到该疫情。 该研究将对可培养和不可培养的霍乱弧菌进行临床和环境监测 坦桑尼亚的两个地区（达累斯萨拉姆及周边地区和基戈马农村）和远北地区 喀麦隆。我们将鉴定来自霍乱患者的霍乱弧菌分离株和裂解弧菌噬菌体 医院护理和社区接触，将指示病例的菌株与附近的菌株进行比较 水源和邻居。这些毒株还将与非洲其他地区的毒株进行比较。生态的 监测将用于将传播与裂解弧菌的存在、天气模式联系起来； 和水的特性。 因此，该提案将描述坦桑尼亚和霍乱的分子流行病学和生态学 喀麦隆提高我们对非洲大片地区霍乱传播模式的了解， 包括限制传播的因素。该研究将评估霍乱作为一种疾病出现的爆发情况 传播有限的局部爆发，或者广泛传播的传入结果 跨越国界。通过提供对包括噬菌体在内的因素的更全面的了解，导致 霍乱的出现、流行以及其崩溃，该项目将指导 控制非洲霍乱的干预措施。