Turning points, reproduction number, and impact of climatological events for multi-wave dengue outbreaks
Turning points, reproduction number, and impact of climatological events for multi-wave dengue outbreaks
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DOI：
10.1111/j.1365-3156.2009.02277.x
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发表时间：
2009-06-01
影响因子：
3.3
通讯作者：
Chen, C. W. S.
中科院分区：
文献类型：
--
作者：
Hsieh, Y. -H.;Chen, C. W. S.
为了研究气候和公共卫生事件，可能会影响到2007年两波登革热爆发在台湾，一个岛屿，热带和亚热带地区，2007年登革热发病率超过了前四年的总和。方法一个多阶段的理查兹模型拟合每周累积登革热数据，以确定爆发的转折点。我们获得了两波疫情的“初始”繁殖数。结果气候变化的转折点分别出现在8月上旬、8月下旬/9月上旬和10月下旬/11月上旬。第一波的“初始”再生数为Ri = 4.67（95%CI：0*-10.92），其中0* = max{0，下限}，第二波的Ri = 3.93（95%CI：1.74-6.13）。最高的相关性是登革热发病率和两个气候变量：最高温度在5周的滞后（r = 0.66和0.71）和总降水量在7周的滞后（r = 0.53.CONCLUSIONS前两个转折点部分归因于两个台风8月初至中旬左右，带来了急剧下降的温度和大量的降雨。气温下降首先导致登革热发病率下降，然后降雨在初秋导致发病率上升。近年来，台湾发生了越来越频繁的夏季登革热大爆发，持续到初冬，可能是由于秋季温暖。这凸显了全球变暖对传染病传播的可能影响。
OBJECTIVES To study climatological and public health events which might have affected the 2007 two-wave dengue outbreak in Taiwan, an island with both tropical and subtropical regions, where the 2007 dengue incidence exceeded the combined total of the previous four years.METHODS A multi-phase Richards model was fitted to weekly cumulative dengue data to pinpoint the turning points of the outbreak. We obtained the 'initial' reproduction numbers for the two waves of the outbreak. By means of correlation analysis we explored the possible impact of climatological events on the occurrence of turning points.RESULTS Three turning points occurred around early August, late August/early September, and late October/early November. The 'initial' reproduction number for the first wave was R-i = 4.67 (95% CI: 0*-10.92), where 0* = max{0, lower bound}, and R-i = 3.93 ( 95% CI: 1.74-6.13) for the second wave. The highest correlation was between dengue incidence and two climatological variables: maximum temperature at a lag of 5 weeks (r = 0.66 and 0.71) and total precipitation at a lag of seven weeks (r = 0.53).CONCLUSIONS The first two turning points were partially attributable to two typhoons around early to mid-August that brought a sharp drop in temperature and substantial rainfall. The drop in temperature first drove the dengue incidence down, then the rainfall drove it up at the beginning of fall. In recent years, Taiwan has witnessed increasingly frequent large summer dengue outbreaks that persisted into early winter, perhaps due to warmer autumns. This highlights the possible impact of global warming on the spread of infectious diseases.