Integrated risk mapping and targeted snail control to support schistosomiasis elimination in Brazil and Cote d'Ivoire under future climate change

综合风险测绘和有针对性的钉螺控制，支持未来气候变化下巴西和科特迪瓦消除血吸虫病

• 批准号: NE/T013591/1
• 负责人: Andrew Brierley
• 金额: $ 32.09万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT013591%2F1
• 关键词: Integrated; risk; mapping; targeted; snail

Schistosomiasis is a debilitating, poverty-linked disease caused by a parasitic worm with a complex life cycle: its transmission requires infection of an obligate intermediate freshwater snail host that is parasitized by larvae from eggs released by infected people. In turn, infected snails shed other parasitic larval stages that eventually reinfect people exposed to parasite-contaminated waters whilst doing their daily chores. The inflammatory processes caused by schistosome eggs cause abdominal pain, diarrhea, blood in stool or urine, that lead to chronic anemia, cognitive impairment in children, growth stunting, infertility, a higher risk of contracting HIV in women and, at high levels of infection, to death from liver failure or bladder cancer. With 800 million people at risk and more than 200 million infected, the vast majority of which are school age children, schistosomiasis is one of the most important, but also most neglected tropical diseases.As both the freshwater snails and the parasite larvae are ectotherms, they have limited ability to thermoregulate . Therefore, their survival, reproduction and dispersal are influenced even by small changes in temperature and temperature variability. Projected climate change is emerging as one of the most powerful drivers of schistosomiasis transmission by altering the geographical distribution of the parasite and its snail hosts and the associated risk of human infections. Understanding climatic, environmental and socio-economic drivers of schistosomiasis and developing novel ecological solutions to fight the disease, improve health, increase food security and alleviate poverty is a scientific and public health priority and will benefit the health of millions of people where schistosomiasis is endemic.We have three main goals: FIRST, we intend to investigate the effect of increasing temperatures, temperature variability and shift in precipitation patterns due to climate change on the dynamics of snail-born schistosomiasis, a debilitating parasitic disease of poverty affecting more than 200 million people worldwide. We will focus on Brazil and Cote d'Ivoire for these compelling reasons: Brazil suffers the highest schistosomiasis burden in the Americas, with an estimated 2-6 million people infected by the S. mansoni worm. Cote d'Ivoire has a high disease prevalence with an estimated 4 million people infected by S. hameatobium and S. mansoni. Projected climate change - along with growing human population, deforestation, expansion of agriculture and of marginal urban settings and the development of dams and irrigation canals known to be associated with increased schistosomiasis risk caused by habitat expansion for, and extirpation of natural predators of, the snail intermediate host - make these two countries particularly vulnerable to this parasitic disease. We will use a hybrid approach integrating species distribution models accounting for the most relevant socio-economic and environmental drivers of schistosomiasis with temperature-driven, process-based mathematical models of the parasite and its intermediate snail hosts to produce maps of present and future risk for schistosomiasis under climate change. SECOND, we intend to conduct initial feasibility and nutritional studies and market analyses of aquaculture of freshwater prawns native of Brazil and of Cote d'Ivoire with the goal of using them as novel biological control agents of schistosome's snail host while, at the same time, promoting the development of small-scale aquaculture businesses. THIRD, to track future changes in the distribution and abundance of the snail hosts, we will develop machine learning algorithms that enable computer vision as an "environmental diagnosis" tool for the quick and accurate identification of potential schistosome-host snails and parasites from field-acquired cellphone images, trained on thousands of images that have been identified to species by DNA barcoding and PCR-RFLP.

血吸虫病是一种与贫困有关的衰弱疾病，由一种具有复杂生活史的寄生虫引起：它的传播需要感染一种专性的中间淡水蜗牛宿主，该宿主由受感染者释放的卵的幼虫寄生。反过来，受感染的蜗牛会排出其他寄生虫幼虫阶段，最终在做日常家务的同时重新感染暴露在被寄生虫污染的水中的人。血吸虫卵引起的炎症过程导致腹痛、腹泻、粪便或尿液中的血液，从而导致慢性贫血、儿童认知障碍、发育迟缓、不孕、妇女感染艾滋病毒的更高风险，如果感染水平较高，则会死于肝功能衰竭或膀胱癌。血吸虫病是最重要但也是最被忽视的热带疾病之一，有8亿人处于危险之中，感染人数超过2亿人，其中绝大多数是学龄儿童。由于淡水蜗牛和寄生虫幼虫都是体温过高的动物，它们的体温调节能力有限。因此，它们的生存、繁殖和扩散甚至会受到温度和温度变异性的微小变化的影响。预计的气候变化正在成为血吸虫病传播的最强大驱动因素之一，因为它改变了寄生虫及其蜗牛宿主的地理分布以及与之相关的人类感染风险。了解血吸虫病的气候、环境和社会经济驱动因素，并开发新的生态解决方案来抗击这种疾病，改善健康，增加粮食安全和减轻贫困，是科学和公共卫生的优先事项，将造福血吸虫病流行地区数百万人的健康。我们有三个主要目标：首先，我们打算调查气候变化导致的气温上升、气温变化和降水模式变化对钉螺出生的血吸虫病动态的影响。血吸虫病是一种影响全球2亿多人的令人衰弱的寄生虫病。我们将把重点放在巴西和科特迪瓦，因为这些令人信服的理由：巴西是美洲血吸虫病负担最重的国家，估计有200万至600万人感染曼氏血吸虫。科特迪瓦的疾病流行率很高，估计有400万人感染沙门氏菌和曼氏沙门氏菌。预计的气候变化--加上人口增长、森林砍伐、农业和城市边缘环境的扩张以及已知与血吸虫病风险增加有关的水坝和灌溉渠的发展--使这两个国家特别容易受到这种寄生虫病的影响。我们将使用一种混合方法，将血吸虫病最相关的社会经济和环境驱动因素的物种分布模型与寄生虫及其中间钉螺宿主的温度驱动、基于过程的数学模型相结合，以生成气候变化下血吸虫病当前和未来风险的地图。第二，我们打算对巴西和科特迪瓦的淡水对虾养殖进行初步的可行性、营养研究和市场分析，目的是将它们用作血吸虫钉螺宿主的新型生防剂，同时促进小型水产养殖企业的发展。第三，为了跟踪未来钉螺宿主分布和丰度的变化，我们将开发机器学习算法，使计算机视觉成为一种“环境诊断”工具，从现场获取的手机图像中快速准确地识别潜在的血吸虫宿主蜗牛和寄生虫，这些图像通过DNA条形码和PCR-RFLP对数千张图像进行了训练。