Coupling between annual and ENSO timescales in the malaria-climate association in Colombia
Coupling between annual and ENSO timescales in the malaria-climate association in Colombia
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DOI：
10.2307/3454707
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发表时间：
2001-05-01
影响因子：
10.4
通讯作者：
Rua, GL
中科院分区：
文献类型：
--
作者：
Poveda, G;Rojas, W;Rua, GL
我们提出的证据表明，厄尔尼诺现象加剧了间日疟原虫和恶性疟原虫在哥伦比亚流行地区的疟疾病例的年度周期的结果，在正常的年度周期的温度和降水的伴随异常。我们同时分析了两个变量在两个时间尺度，以及详细的空间（市政）和时间（每月）记录的相关性和功率谱分析。在“正常年份”，哥伦比亚农村的地方性疟疾呈现出明确的“正常”年周期，这与普遍的气候条件密切相关，主要是平均温度、降水、露点和河流排放。在历史上的厄尔尼诺事件（年际雾凇规模）期间，疟疾爆发的时间与年度周期没有变化，但病例数量增加。这种异常与水文和气候异常的一致模式有关：平均温度升高，降水减少，露点增加，河流流量减少，所有这些都有利于疟疾传播。这种耦合解释了为什么厄尔尼诺年的下半年（0）和上半年（+1）的影响似乎更强，更持久。我们说明了这一发现与不同的地方在布埃纳文图拉（太平洋沿岸）和高加索（沿着考卡河洪泛区）的数据，但结论已被发现有效的多个地方在整个流行地区的哥伦比亚。气候-疟疾系统中年度和年际时间尺度之间的耦合为理解环境、昆虫学和流行病学因素与疟疾爆发之间的确切联系提供了新的思路，也为公共卫生干预计划中这些时间尺度的耦合提供了新的思路。
We present evidence that the El Nino phenomenon intensifies the annual cycle of malaria cases for Plasmodium vivax and Plasmodium falciparum in endemic areas of Colombia as a consequence of concomitant anomalies in the normal annual cycle of temperature and precipitation. We used simultaneous analyses of both variables at both timescales, as well as correlation and power spectral analyses of detailed spatial (municipal) and temporal (monthly) records. During "normal years," endemic malaria in rural Colombia exhibits a clear-cut "normal" annual cycle, which is tightly associated with prevalent climatic conditions, mainly mean temperature, precipitation, dew point, and river discharges. During historical El Nino events (interannual rime scale), the timing of malaria outbreaks does not change from the annual cycle, but the number of cases intensifies. Such anomalies are associated with a consistent pattern of hydrological and climatic anomalies: increase in mean temperature, decrease in precipitation, increase in dew point, and decrease in river discharges, all of:which favor malaria transmission Such coupling explains why the effect appears stronger and more persistent during the second half of El Nino's year (0), and during the first half of the year (+1). We illustrate this finding with data for diverse localities in Buenaventura (on the Pacific coast) and Caucasia (along the Cauca river floodplain), but conclusions have been found valid for multiple localities throughout endemic regions of Colombia. The identified coupling between annual and interannual timescales in the climate-malaria system shed new light toward understanding the exact linkages between environmental, entomological, and epidemiological factors conductive to malaria outbreaks, and also imposes the coupling of those timescales in public health intervention programs.