Refractory periods and climate forcing in cholera dynamics
Refractory periods and climate forcing in cholera dynamics
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DOI：
10.1038/nature03820
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发表时间：
2005-08-04
期刊：
影响因子：
64.8
通讯作者：
Mostafa, G
中科院分区：
文献类型：
--
作者：
Koelle, K;Rod贸, X;Mostafa, G
包括霍乱、疟疾和登革热在内的许多传染病的爆发在超过1年的特征周期内变化（1，2）。气候变率驱动这些年际周期的证据一直存在很大争议，主要是因为在考虑宿主免疫等机制产生的非线性流行病学动力学的同时，很难将环境强迫的贡献分离出来（2-4）。在这里，我们表明，一个关键的相互作用的环境强迫，特别是气候变化，和暂时的免疫力解释了年际疾病周期存在于一个四十年的霍乱时间序列从Matlab，孟加拉国。我们重建的传输率，关键的流行病学参数受外在强迫，随着时间的推移，为优势菌株（厄尔尼诺）与非线性人口模型，允许内在免疫的贡献效应。传输显示出明显的年际变化，与长期（7年以上，季风降雨和雅鲁藏布江流量）和短期（7年以下，孟加拉国洪水范围，孟加拉湾海面温度和厄尔尼诺南方涛动）的气候模式有很强的对应关系。说明在不应期，当人口易感性水平低的结果，免疫力和霍乱爆发的规模只有微弱的气候强迫的外在和内在因素之间的相互作用的重要性。
Outbreaks of many infectious diseases, including cholera, malaria and dengue, vary over characteristic periods longer than 1 year(1,2). Evidence that climate variability drives these interannual cycles has been highly controversial, chiefly because it is difficult to isolate the contribution of environmental forcing while taking into account nonlinear epidemiological dynamics generated by mechanisms such as host immunity(2-4). Here we show that a critical interplay of environmental forcing, specifically climate variability, and temporary immunity explains the interannual disease cycles present in a four-decade cholera time series from Matlab, Bangladesh. We reconstruct the transmission rate, the key epidemiological parameter affected by extrinsic forcing, over time for the predominant strain ( El Tor) with a nonlinear population model that permits a contributing effect of intrinsic immunity. Transmission shows clear interannual variability with a strong correspondence to climate patterns at long periods ( over 7 years, for monsoon rains and Brahmaputra river discharge) and at shorter periods ( under 7 years, for flood extent in Bangladesh, sea surface temperatures in the Bay of Bengal and the El Nino Southern Oscillation). The importance of the interplay between extrinsic and intrinsic factors in determining disease dynamics is illustrated during refractory periods, when population susceptibility levels are low as the result of immunity and the size of cholera outbreaks only weakly reflects climate forcing.