Department of Ecology and Evolutionary Biology, Center for Computational Medicine and Bioinformatics, and Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109.
Proc Natl Acad Sci U S A. 2013 Sep 10;110(37):15157-62. doi: 10.1073/pnas.1305728110. Epub 2013 Aug 13.
In arid areas, people living in the proximity of irrigation infrastructure are potentially exposed to a higher risk of malaria due to changes in ecohydrological conditions that lead to increased vector abundance. However, irrigation provides a pathway to economic prosperity that over longer time scales is expected to counteract these negative effects. A better understanding of this transition between increased malaria risk and regional elimination, in particular whether it is slow or abrupt, is relevant to sustainable development and disease management. By relying on space as a surrogate for stages of time, we investigate this transition in a semidesert region of India where a megairrigation project is underway and expected to cover more than 1,900 million hectares and benefit around 1 million farmers. Based on spatio-temporal epidemiological cases of Plasmodium vivax malaria and land-use irrigation from remote sensing sources, we show that this transition is characterized by an enhanced risk in areas adjacent to the trunk of the irrigation network, despite a forceful and costly insecticide-based control. Moreover, this transition between climate-driven epidemics and sustained low risk has already lasted a decade. Given the magnitude of these projects, these results suggest that increased health costs have to be planned for over a long time horizon. They further highlight the need to integrate assessments of both health and environmental impacts to guide adaptive mitigation strategies. Our results should help to define and track these transitions in other arid parts of the world subjected to similar tradeoffs.
在干旱地区，由于生态水文学条件的变化导致病媒滋生增加，居住在灌溉基础设施附近的人面临更高的疟疾风险。然而，灌溉为经济繁荣提供了一条途径，从长远来看，预计这种繁荣将抵消这些负面影响。更好地了解这种疟疾风险增加与区域消除之间的转变，特别是它是缓慢还是突然的，与可持续发展和疾病管理有关。通过依靠空间来替代时间的阶段，我们在印度的一个半沙漠地区进行了这项研究，该地区正在进行一个大型灌溉项目，预计将覆盖超过 19 亿公顷土地，并使大约 100 万农民受益。基于从遥感来源获取的空间和时间流行病学的间日疟病例和土地利用灌溉数据，我们表明，尽管采用了强有力且昂贵的基于杀虫剂的控制措施，但在灌溉网络主干附近的区域，这种风险正在增加。此外，这种由气候驱动的流行病与持续低风险之间的转变已经持续了十年。鉴于这些项目的规模之大，需要在很长的时间跨度内规划增加的卫生成本。它们进一步强调需要将健康和环境影响的评估结合起来，以指导适应性缓解策略。我们的研究结果应有助于在世界其他面临类似权衡的干旱地区定义和跟踪这些转变。
