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/T013710/1
• 负责人: Rachel Norman
• 金额: $ 31.96万
• 依托单位: University of Stirling
• 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: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT013710%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穷有关的使人衰弱的疾病，由一种具有复杂生命周期的寄生虫引起：其传播需要感染一种专性中间淡水蜗牛宿主，该宿主被感染者释放的卵的幼虫寄生。反过来，受感染的蜗牛会脱落其他阶段的寄生虫幼虫，这些幼虫最终会再次感染那些在做日常家务时暴露在受寄生虫污染的沃茨中的人。由寄生虫卵引起的炎症过程会导致腹痛、腹泻、便血或尿血，从而导致慢性贫血、儿童认知障碍、生长发育迟缓、不孕症、妇女感染艾滋病毒的风险增加，在高感染水平下，会因肝功能衰竭或膀胱癌而死亡。血吸虫病是世界上最严重的热带病之一，但也是最容易被忽视的热带病。目前，世界上有8亿人面临感染的危险，其中2亿多人受到感染，其中绝大多数是学龄儿童。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疾病、改善健康、提高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，我们打算调查温度升高、温度变化和气候变化引起的降水模式变化对螺生血吸虫病动态的影响，这是一种使人衰弱的贫困寄生虫病，影响着全世界2亿多人。我们将重点关注巴西和科特迪瓦，因为这些令人信服的原因：巴西是美洲血吸虫病负担最重的国家，估计有200万至600万人感染了S。曼氏线虫科特迪瓦的疾病流行率很高，估计有400万人感染了沙门氏菌。hameatobium和S. mansoni预计的气候变化-沿着人口增长、森林砍伐、农业和边缘城市环境的扩大以及水坝和灌溉渠的开发，这些都与蜗牛中间宿主的栖息地扩大和天敌灭绝造成的血吸虫病风险增加有关-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，将占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蜗牛宿主的温度驱动，基于过程的数学模型相结合，以绘制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原产的淡水对虾进行初步的可行性和营养研究以及市场分析，目的是将其用作新的生物控制剂，同时促进小规模水产养殖业的发展。第三，为了跟踪蜗牛宿主的分布和丰度的未来变化，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，用于从现场获得的手机图像中快速准确地识别潜在的寄生虫宿主蜗牛和寄生虫，并在数千张通过DNA条形码和PCR-RFLP识别的图像上进行训练。