Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam
Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam
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DOI：
10.1016/j.epidem.2015.06.002
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发表时间：
2015-12-01
期刊：
影响因子：
3.8
通讯作者：
Horby, Peter
中科院分区：
文献类型：
--
作者：
Pham Quang Thai;Choisy, Marc;Horby, Peter
背景：实验和生态学研究表明，气候因素在推动流感流行病学中的作用。特别是，低绝对湿度(AH)已被证明可增加流感病毒的传播性，并已被确定为解释温带地区流行的原因。在这里，我们的目标是研究越南流感样病(ILI)流行病学的潜在气候驱动因素，越南是一个热带国家，具有高度气候多样性的特点。我们的重点是量化和解释ILI的季节性。方法：我们使用了越南67个气象站18年(1993-2010年)按省份(52个)和月度气候变量(最低、平均、最高温度、绝对和相对湿度、降雨量和日照时数)汇总的ILI月报。从全球小波谱中量化季节性，使用1年期间的功率值作为季节性强度的衡量标准。7个气候时间序列由534个概要统计量表征，这些统计量被输入回归树以识别与AH季节性有关的因素。利用NCEP/NCAR项目的模拟气候时间序列将结果外推到全球尺度。结果：越南ILI的季节性强度可以用AH季节性强度来解释。我们发现，在AH季节波动较弱的省份(年平均功率17.6)，ILI的季节性较弱。在越南，AH与ILI呈正相关。结论：我们的结果确定了AH在热带地区ILI流行病学中的作用。然而，与温带地区相比，高而不是低的AH与ILI活性增加有关。AH值的波动可能是温带和热带地区ILI季节性的基础和统一的气候因素。或者，在冷干和热湿环境中，AH在疾病传播中的作用机制可能不同。(C)2015年提交人。由Elsevier B.V.出版。这是CC BY-NC-ND许可证(http://creativecommons.org/licenses/by-nc-nd/4.0/).下的一篇开放获取文章
Background: Experimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. In particular, low absolute humidity (AH) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. Here, we aim to study the potential climatic drivers of influenza-like illness (ILI) epidemiology in Vietnam, a tropical country characterized by a high diversity of climates. We specifically focus on quantifying and explaining the seasonality of ILI.Methods: We used 18 years (1993-2010) of monthly ILI notifications aggregated by province (52) and monthly climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across Vietnam. Seasonalities were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of seasonality. The 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the seasonality of AH. Results were extrapolated to the global scale using simulated climatic times series from the NCEP/NCAR project.Results: The intensity of ILI seasonality in Vietnam is best explained by the intensity of AH seasonality. We find that ILI seasonality is weak in provinces experiencing weak seasonal fluctuations in AH (annual power 17.6). In Vietnam, AH and ILI are positively correlated.Conclusions: Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).