Climate forcing and desert malaria: the effect of irrigation.
Climate forcing and desert malaria: the effect of irrigation.
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DOI：
10.1186/1475-2875-10-190
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发表时间：
2011-07-14
期刊：
影响因子：
3
通讯作者：
Pascual M
中科院分区：
文献类型：
--
作者：
Baeza A;Bouma MJ;Dobson AP;Dhiman R;Srivastava HC;Pascual M
降雨变异性和有关的植被遥感指数是发展干旱地区疟疾流行早期预警系统的核心。近几十年来，由于灌溉的增加，土地使用方式发生了相当大的变化，这就提出了有关疟疾动态变化及其与气候强迫耦合的重要问题。在这里，灌溉水平对疟疾流行的影响通过广泛的时间序列数据来解决，这些数据涉及印度西北部五个地区20多年来确诊的恶性疟原虫每月病例。这项工作特别侧重于疟疾流行对降雨强迫的反应，以及这种反应如何受到灌溉增加的影响。归一化植被指数（NDVI）的遥感数据被用作降雨的综合测量，以检查地区内和区域尺度上的相关图。这些分析具体探讨了灌溉是否降低了疟疾发病率与气候变率之间的耦合，以及这是否反映了(1)NDVI作为一个有用的风险指标的分解，(2)降雨强迫的减弱和随之而来的流行病风险的降低，或者(3)疟疾传播控制的加强。比较了NDVI与降雨的预测能力，采用简单线性模型和小波分析分别研究了NDVI与疟疾变率在时间和频率上的相关性。结果表明，灌溉抑制了气候强迫对疟疾流行的规模和频率的影响，因此降低了其可预测性。在灌溉水平较低的情况下，这种解耦反映了局部而非区域NDVI作为降雨强迫指标的分解。在灌溉水平较高的地区，气候变率作用的减弱可能因控制水平的提高而加剧；然而，这并没有导致实际患病风险的显著降低。这意味着灌溉可能导致更多的疟疾地方病条件，如果这些气候事件与随着时间的推移放松控制同时发生，就有可能因过量降雨而造成意想不到的大规模流行病。讨论了我们的研究结果对干旱地区疟疾流行控制政策的影响。
Rainfall variability and associated remote sensing indices for vegetation are central to the development of early warning systems for epidemic malaria in arid regions. The considerable change in land-use practices resulting from increasing irrigation in recent decades raises important questions on concomitant change in malaria dynamics and its coupling to climate forcing. Here, the consequences of irrigation level for malaria epidemics are addressed with extensive time series data for confirmed Plasmodium falciparum monthly cases, spanning over two decades for five districts in north-west India. The work specifically focuses on the response of malaria epidemics to rainfall forcing and how this response is affected by increasing irrigation. Remote sensing data for the Normalized Difference Vegetation Index (NDVI) are used as an integrated measure of rainfall to examine correlation maps within the districts and at regional scales. The analyses specifically address whether irrigation has decreased the coupling between malaria incidence and climate variability, and whether this reflects (1) a breakdown of NDVI as a useful indicator of risk, (2) a weakening of rainfall forcing and a concomitant decrease in epidemic risk, or (3) an increase in the control of malaria transmission. The predictive power of NDVI is compared against that of rainfall, using simple linear models and wavelet analysis to study the association of NDVI and malaria variability in the time and in the frequency domain respectively. The results show that irrigation dampens the influence of climate forcing on the magnitude and frequency of malaria epidemics and, therefore, reduces their predictability. At low irrigation levels, this decoupling reflects a breakdown of local but not regional NDVI as an indicator of rainfall forcing. At higher levels of irrigation, the weakened role of climate variability may be compounded by increased levels of control; nevertheless this leads to no significant decrease in the actual risk of disease. This implies that irrigation can lead to more endemic conditions for malaria, creating the potential for unexpectedly large epidemics in response to excess rainfall if these climatic events coincide with a relaxation of control over time. The implications of our findings for control policies of epidemic malaria in arid regions are discussed.
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影响因子：
3
作者：
Ng'ang'a PN;Jayasinghe G;Kimani V;Shililu J;Kabutha C;Kabuage L;Githure J;Mutero C
通讯作者：
Mutero C
影响因子：
64.8
作者：
Thomson, MC;Doblas-Reyes, FJ;Palmer, TN
通讯作者：
Palmer, TN
DOI：
10.1016/s0035-9203(98)90936-1
发表时间：
1998-01-01
影响因子：
2.2
作者：
Hay, SI;Snow, RW;Rogers, DJ
通讯作者：
Rogers, DJ
DOI：
10.4269/ajtmh.2006.74.1034
发表时间：
2006-06-01
影响因子：
3.3
作者：
Yasuoka, Junko;Mangione, Thomas W.;Levins, Richard
通讯作者：
Levins, Richard
DOI：
10.1016/s0169-4758(97)01097-1
发表时间：
1997-08-01
期刊：
PARASITOLOGY TODAY
影响因子：
--
作者：
Thomson, MC;Connor, SJ;Flasse, SP
通讯作者：
Flasse, SP