发表机构
McMaster University（麦克马斯特大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究分析伦敦1842-1939年猩红热数据，发现流行周期从4年延长至8年，死亡数骤降，通过机制模型揭示有效繁殖数与季节性强迫变化是主因，可能涉及病原体进化。
AI 中文摘要
对英国伦敦1842年至1939年的每周猩红热（SF）死亡记录，以及1901年至1939年的通报病例记录进行分析，揭示了一个强烈的年度流行模式，其高峰出现在秋季。除了年度流行模式外，这一长时间序列还揭示了一个周期随几十年间逐渐延长的周期性包络。特别是，包络周期在1880年至1920年间从约四年增加到约八年，这与前抗生素时代猩红热死亡人数的急剧下降（从每年约2300例降至约80例）相吻合。我们使用小波变换量化猩红热时间序列的频谱特征，并尝试通过猩红热传播动力学的机制数学模型来解释频率结构随时间变化的原因。我们部分从文献中估计模型参数，部分通过联合拟合死亡率和发病率来估计。我们使用机制性转变分析（同时考虑模型解中的吸引子和瞬态）将观察到的频率结构变化与估计的模型参数变化联系起来。我们发现，时间序列中几乎所有的频谱演化都可以通过有效繁殖数和季节性强迫幅度的变化来解释。这些变化反映了观察到的出生率变化以及推断的传播变化，后者可能部分源于病原体进化。
英文摘要
Weekly scarlet fever (SF) mortality records for London, UK, from 1842 to 1939, together with notified case records from 1901 to 1939, reveal a strong annual epidemic pattern with peak prevalence in the autumn. In addition to the annual epidemic pattern, this long time series reveals a cyclical envelope with a period that lengthened over the decades. In particular, the period of the envelope increased from about four years to about eight years between 1880 and 1920, coinciding with a dramatic decline in pre-antibiotic-era SF deaths (from about 2300/yr to about 80/yr). We quantify the spectral features of the SF time series using a wavelet transform, and attempt to explain why the frequency structure changed over time, using a mechanistic mathematical model of SF transmission dynamics. We estimate the parameters of the model in part from the literature and in part by fitting mortality and incidence jointly. We use a mechanistic transition analysis (considering both attractors and transients in model solutions) to relate the observed changes in frequency structure to our estimated changes in model parameters. We find that almost all spectral evolution in the time series can be explained by changes in the effective reproduction number and the amplitude of seasonal forcing. These changes reflect observed variation in birth rates together with inferred changes in transmission, which may in part have arisen through pathogen evolution.
Comments42 pages, 14 figures, 3 Tables
