As the COVID-19 pandemic continues, it has become painfully evident how vulnerable economic systems can be to widespread and persistent diseases.
在低收入和中等收入国家，特别是在撒哈拉以南非洲，农业发挥着基本的发展作用，因为它构成了各国经济的主要成员，雇用了一半以上的劳动力。虽然主要是耕种的特点，但通过低生产率，农业仍然是扶贫最强大的工具，促进家庭收入的多样化和增长，并允许进入改进的生产技术。
Simultaneously, however, agricultural development facilitated by the construction of large-scale irrigation schemes foster the propagation of schistosomiasis, a water-based debilitating parasitic disease that affects an estimated 250 million people, more than 85% of whom live in sub-Saharan Africa. The parasite species that cause the two main forms of schistosomiasis in Africa are血吸虫曼逊（引起肠道血吸虫病）和血吸虫haematobium(causing urogenital schistosomiasis).
该疾病的特征在于涉及两种繁殖阶段的复杂生命周期，首先是一种具有作为中间宿主的特定淡水蜗牛物种，其次是人体宿主的性繁殖。在未经治疗的人类中，先进的血吸虫病形式导致肾衰竭，膀胱癌，肝纤维化，以及艾滋病毒传播的风险增加。最高的寄生虫负担通常是由学龄儿童承担的，并且该疾病与贫血，衰退和认知赤字有关，导致学校表现差和更高的辍学率。主要水资源基础设施的开发和管理，包括灌溉运河和水库，通过扩大了中间宿主蜗牛的合适栖息地，修改了疾病的分布的动态。由于这些长期影响，血吸虫病被认为对被感染的个人，家庭和严重影响的社区产生大量的健康，社会和金融负担。
因此，血吸虫病动力学，水资源开发和经济发展被强烈相互关联。但是，他们的并发效果和联合动力尚未得到充分探索。在我们的论文中，我们通过对血吸虫病的经济影响通过其农业生产负担来填补这种差距。我们表明，这种负担很大：我们估计，消除布基纳法索的血吸虫病会将平均作物产量增加约7％，高感染簇上升至32％。对于诸如布基纳法索等内撒哈拉国家的内陆撒哈拉国家，其中80％的人口在农业部门工作，这种影响特别戏剧性。
符合疾病的衰弱性质，我们确定了疾病的经济负担，这是一种不直接影响生产所需的劳动力或物理投入量（例如种子和机械），而是减少其有效性。换句话说，慢性血吸虫病导致农民成为较少to farm efficiently: this generates a spiral of deleterious effects that can have potentially dramatic consequences, particularly in countries such as Burkina Faso where agriculture is mostly of the subsistence type.
为了使事情变得更糟，这种负担是通过贫困和减贫措施如水资源开发等贫困的矛盾地加强。我们发现贫困家庭遭受不成比例的负担（高强度集群32％），并且靠近大型水坝的村庄经历了由于血吸虫病（约20％约20％）的农业产量损失更高。
地理因素在其中发挥了关键作用,因为这增加我n yield loss due to schistosomiasis is contained within a radius of 20-30km from the dams, and villages located at a further distance from the dams suffer a reduced burden. The consequences from the standpoint of inequality are substantial: these large water infrastructures are in majority built for hydroelectrical purposes and geared towards urban electrification. This means that those who live in the areas adjacent to the dams suffer the most deleterious consequences in terms of disease burden, whilst reaping only a small part of their benefits. Fortunately, our results are not entirely bleak. Smaller-scale water infrastructures, which are equally fundamental measures of poverty control, especially in the poorest parts of the sub-Saharan region, do not seem to amplify the economic burden of schistosomiasis, and hence should be incentivized and strengthened.
We obtain our results by exploiting recent developments in disease mapping. We obtain high-resolution schistosomiasis prevalence maps via Bayesian geostatistical methods, which have been used in a variety of public health contexts but have not yet been paired with survey data on households and agricultural production. Because of the complexity of the dynamics of schistosomiasis and its interlinkages with such a large set of socioeconomic and environmental factors, we implement a novel mix of methods. We use the spatial density of the snail intermediate host of the血吸虫寄生虫建立因果关系，并用机器学习和空间技术细化分析。
Our study illustrates the potential benefits of combining epidemiological and economic methods in the analysis of the human cost of endemic diseases. Our approach is “data-hungry”, especially in the study of the impact of endemic diseases at a household level, which can represent a hurdle for wider application. Yet, recent methodological and technological advances increasingly allow researchers to access a wealth of information which was until recently unthinkable. Conditional on this, our approach can be applied to any other country in which schistosomiasis is endemic and indeed, to the economic impact of many other diseases.
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