Environmental transmission of cholera in Tanzania: Building resilience in rural communities

这一跨学科项目利用物理科学的不同方面，在理解和预测环境霍乱传播方面取得了重大进展。该项目的成果将用于改进对人群接触霍乱弧菌的地点和暴露风险的预测。霍乱弧菌是霍乱的宿主。该项目建立在通过矿物颗粒内的发光信号来耦合沉积物运动和环境光暴露方面的先前发展(McGuire和Rhodes 2015a，b；Gray等人，2015)，并以EPSRC的三个核心主题为基础：物理科学、医疗保健技术和与环境变化共存。该项目将制定解决方案，以改善人类健康和对水媒疾病传播的了解，并为应对水安全的重大挑战作出贡献。尽管取得了重大科学进展，但在我们经历第七次霍乱大流行(Mpazi和Mnyi ka，2005年)之际，霍乱继续在全球南部摧毁生命和生计，全球报告每年约有290万例霍乱病例和约9.5万人死亡(世卫组织，2018年)。仅在非洲，就有4000万人生活在霍乱易发地区(Anderson，2020)。自1974年以来，坦桑尼亚一直是非洲大陆霍乱报告最多的县之一，截至2018年，有250,000多例霍乱病例和13,078人死亡(Lessler等人。2018年)。在坦桑尼亚，霍乱暴发的背景是卫生系统因世界银行实行的价格波动和偿债政策而蒙受损失，农村穷人感受到的不利影响不成比例。(Baker等人，2013年；Mamdani&Bunser，2004年)。此外，在新冠肺炎时代，卫生系统不堪重负，国家的财政负担越来越大(萨利赫，2020年)。最近的气候模拟工作表明，东非将经历更短、更强烈的雨季，随后是严重干旱，预计这将导致非洲霍乱负担显著向非洲大陆东部转移(Colwell，1996；Traeup等人)。2011年)。缺水迫使人们使用不安全的水源，而洪水会导致饮用水的粪便污染(Moore等人。2017年)。这突出表明需要准确预测农村地区的霍乱暴发，以便能够及时分配资源(Akanda等人)。2011年；Azman等人。2019年；Emch等人。2008)，并最大限度地发挥支撑坦桑尼亚医疗体系的投资价值。细菌可以以生物膜的形式附着在矿物表面。霍乱弧菌能够在不利于其生存和生长的条件下形成保护机制并进入休眠状态，当条件改善时2可以恢复毒力(Lutz等人，2013年)。已在河流和湖泊细粒沉积物存储中记录到霍乱弧菌处于这种无毒状态，在那里它一直持续到暴雨等干扰事件开始，然后导致暴发(Abia等人，2017年；Perkins等人，2014年)。因此，霍乱弧菌储存在河流和湖泊沉积物中，这是活跃的河道和湖泊系统中的泥浆物质，构成了重大的公共健康风险。了解这些存储在哪里，以及在高流量时期沉积物是如何运输的，对于预测霍乱爆发具有巨大的潜力。发光技术的新应用将被用于构建优化的方法和设备，以监测和测量河流和湖泊系统内的水文过程，并将这些应用于应对上述公共健康威胁。发光利用了捕获在石英和长石颗粒晶格中的电荷。当谷物被掩埋并受到自然电离辐射时，电荷会积聚，当谷物暴露在热或光下时，电荷会减少。这可以被测量为发光信号，通过加热或将颗粒暴露在光中来刺激

This interdisciplinary project uses different aspects of physical science to make significant advances in understanding and predicting environmental cholera transmission. The project outcomes will be used to improve prediction of location and exposure risk of populations to Vibrio cholerae, the bacterium that hosts cholera. The project builds on previous developments in the coupling of sediment movement and ambient light exposure via luminescence signals within mineral grains (McGuire and Rhodes 2015a, b; Gray et al., 2015), and is based within three core EPSRC themes: Physical Science, Healthcare Technologies, and Living with Environmental Change. This project will devise solutions to improve human health and understanding of water-borne disease transmission, and represents a contribution to the grand challenges of water security. Despite significant scientific advances, cholera continues to destroy lives and livelihoods in the global south as we live through the seventh cholera pandemic (Mpazi & Mnyika, 2005), with global reports of ~2.9 million cases and ~95,000 deaths annually (WHO, 2018). In Africa alone, 40 million people live in cholera-prone areas (Anderson, 2020). Since 1974, Tanzania has remained one of the top cholera-reporting counties on the continent, with over 250,000 cases and 13,078 deaths, up to 2018 (Lessler et al. 2018). In Tanzania, cholera outbreaks occur against a backdrop of a health system suffering in the wake of volatile prices and debt-servicing policies imposed by the World Bank, the adverse effects of which are disproportionately felt by the rural poor. (Baker et al., 2013; Mamdani & Bangser, 2004). Furthermore, in times of COVID-19 health systems are overwhelmed and the country is under increasing financial burden (Saleh, 2020). Recent climate modelling efforts suggest East Africa will experience shorter, more intense wet seasons, followed by severe drought, which is projected to cause a significant shift in the african cholera burden towards the east of the continent (Colwell, 1996; Traeup et al. 2011). Water scarcity forces people to use unsafe water sources, whereas flooding causes fecal contamination of drinking water (Moore et al. 2017). This highlights the need for accurate prediction of cholera outbreaks in rural areas, to enable the timely allocation of resources (Akanda et al. 2011; Azman et al. 2019; Emch et al. 2008), and maximise the value of investment that underpins the Tanzanian healthcare system. Bacteria can attach to mineral surfaces as biofilms. Vibrio cholerae are able to develop protective mechanisms and enter a state of dormancy in conditions unfavourable for its survival and growth, and 2 can return to virulence when conditions improve (Lutz et al., 2013). Vibrio cholerae have been recorded in this non-virulent state in fluvial and lacustrine fine-grained sediment stores, where it persists until the onset of a disturbance event, such as heavy rainfall, and then causes an outbreak (Abia et al., 2017; Perkins et al., 2014). Thus, stores of Vibrio cholerae in fluvial and lacustrine sediment, which is muddy material within active river channels and lake systems, pose a major public health risk. Understanding where these stores are, and how sediment is transported during periods of high flow, holds great potential for predicting cholera outbreaks. Novel application of luminescence techniques will be used to construct optimised approaches and equipment to monitor and measure hydrological processes within fluvial and lacustrine systems, and apply these to tackle the public health threat described above. Luminescence exploits the charge trapped within the crystal lattice of quartz and feldspar grains. Charge is built up when grains are buried and subject to natural ionising radiation, and reduces when grains are exposed to heat or light. This can be measured as a luminescence signal, stimulated by heating or exposing the grains to light