World Mosquito Program, Colombia; Departamento de Geociencias y Medio Ambiente, Universidad Nacional de Colombia, Medellín, Colombia.
Departamento de Geociencias y Medio Ambiente, Universidad Nacional de Colombia, Medellín, Colombia.
Acta Trop. 2021 Dec;224:106136. doi: 10.1016/j.actatropica.2021.106136. Epub 2021 Sep 21.
Dengue virus (DENV) is an endemic disease in the hot and humid low-lands of Colombia. We characterize the association of monthly series of dengue cases with indices of El Niño/Southern Oscillation (ENSO) at the tropical Pacific and local climatic variables in Colombia during the period 2007-2017 at different temporal and spatial scales. For estimation purposes, we use lagged cross-correlations (Pearson test), cross-wavelet analysis (wavelet cross spectrum, and wavelet coherence), as well as a novel nonlinear causality method, PCMCI, that allows identifying common causal drivers and links among high dimensional simultaneous and time-lagged variables. Our results evidence the strong association of DENV cases in Colombia with ENSO indices and with local temperature and rainfall. El Niño (La Niña) phenomenon is related to an increase (decrease) of dengue cases nationally and in most regions and departments, with maximum correlations occurring at shorter time lags in the Pacific and Andes regions, closer to the Pacific Ocean. This association is mainly explained by the ENSO-driven increase in temperature and decrease in rainfall, especially in the Andes and Pacific regions. The influence of ENSO is not stationary, given the reduction of DENV cases since 2005, and that local climate variables vary in space and time, which prevents to extrapolate results from one region to another. The association between DENV and ENSO varies at national and regional scales when data are disaggregated by seasons, being stronger in DJF and weaker in SON. Overall, the Pacific and Andes regions control the relationship between dengue dynamics and ENSO at national scale. Cross-wavelet analysis indicates that the ENSO-DENV relation in Colombia exhibits a strong coherence in the 12 to 16-months frequency band, which implies the frequency locking between the annual cycle and the interannual (ENSO) timescales. Results of nonlinear causality metrics reveal the complex concomitant effects of ENSO and local climate variables, while offering new insights to develop early warning systems for DENV in Colombia.
登革热病毒（DENV）是哥伦比亚湿热低地的地方病。我们在不同的时空尺度上，对 2007-2017 年期间，登革热病例的月序列与热带太平洋的厄尔尼诺/南方涛动（ENSO）指数和哥伦比亚当地气候变量之间的关联进行了描述。为了进行估计，我们使用了滞后交叉相关（Pearson 检验）、交叉小波分析（小波交叉谱和小波相干性）以及一种新的非线性因果方法 PCMCI，该方法可用于识别高维同时和时滞变量之间的共同因果驱动因素和联系。我们的结果表明，哥伦比亚的登革热病例与 ENSO 指数以及当地温度和降雨量之间存在很强的关联。厄尔尼诺（拉尼娜）现象与全国和大多数地区和部门的登革热病例增加（减少）有关，在太平洋和安第斯地区，相关最大的时间滞后较短，更接近太平洋。这种关联主要是由 ENSO 驱动的温度升高和降雨量减少引起的，尤其是在安第斯山脉和太平洋地区。鉴于自 2005 年以来登革热病例减少，以及当地气候变量在空间和时间上的变化，ENSO 的影响并不稳定，这使得无法将一个地区的结果外推到另一个地区。当按季节对数据进行细分时，登革热和 ENSO 之间的关联在国家和地区范围内会发生变化，在 DJF 季节较强，而在 SON 季节较弱。总体而言，太平洋和安第斯地区控制着全国范围内登革热动态与 ENSO 之间的关系。交叉小波分析表明，哥伦比亚的 ENSO-登革热关系在 12 至 16 个月的频段内具有很强的相干性，这意味着年际周期和年际（ENSO）时间尺度之间的频率锁定。非线性因果度量的结果揭示了 ENSO 和当地气候变量的复杂伴随效应，同时为哥伦比亚开发登革热早期预警系统提供了新的见解。
