Mathematical, Computational & Modeling Sciences Center, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA.
Vaccine. 2011 Jul 22;29 Suppl 2(Suppl 2):B21-6. doi: 10.1016/j.vaccine.2011.02.048.
Increasing our knowledge of past influenza pandemic patterns in different regions of the world is crucial to guide preparedness plans against future influenza pandemics. Here, we undertook extensive archival collection efforts from three representative cities of Peru-Lima in the central coast, Iquitos in the northeastern Amazon region, Ica in the southern coast-to characterize the temporal, age and geographic patterns of the 1918-1920 influenza pandemic in this country.
We analyzed historical documents describing the 1918-1920 influenza pandemic in Peru and retrieved individual mortality records from local provincial archives for quantitative analysis. We applied seasonal excess mortality models to daily and monthly respiratory mortality rates for 1917-1920 and quantified transmissibility estimates based on the daily growth rate in respiratory deaths.
A total of 52,739 individual mortality records were inspected from local provincial archives. We found evidence for an initial mild pandemic wave during July-September 1918 in Lima, identified a synchronized severe pandemic wave of respiratory mortality in all three locations during November 1918-February 1919, and a severe pandemic wave during January 1920-March 1920 in Lima and July-October 1920 in Ica. There was no recrudescent pandemic wave in 1920 in Iquitos. Remarkably, Lima experienced the brunt of the 1918-1920 excess mortality impact during the 1920 recrudescent wave, with all age groups experiencing an increase in all cause excess mortality from 1918-1919 to 1920. Middle age groups experienced the highest excess mortality impact, relative to baseline levels, in the 1918-1919 and 1920 pandemic waves. Cumulative excess mortality rates for the 1918-1920 pandemic period were higher in Iquitos (2.9%) than Lima (1.6%). The mean reproduction number for Lima was estimated in the range 1.3-1.5.
We identified synchronized pandemic waves of intense excess respiratory mortality during November 1918-February 1919 in Lima, Iquitos, Ica, followed by asynchronous recrudescent waves in 1920. Cumulative data from quantitative studies of the 1918 influenza pandemic in Latin American settings have confirmed the high mortality impact associated with this pandemic. Further historical studies in lesser studied regions of Latin America, Africa, and Asia are warranted for a full understanding of the global impact of the 1918 pandemic virus.
增加我们对世界不同地区过去流感大流行模式的了解对于指导针对未来流感大流行的防范计划至关重要。在这里，我们从秘鲁的三个具有代表性的城市（利马位于中海岸，伊基托斯位于东北亚马逊地区，伊卡位于南部海岸）进行了广泛的档案收集工作，以描述该国 1918-1920 年流感大流行的时间、年龄和地理模式。
我们分析了描述秘鲁 1918-1920 年流感大流行的历史文献，并从当地省级档案馆检索了个体死亡率记录进行定量分析。我们将季节性超额死亡率模型应用于 1917-1920 年的每日和每月呼吸死亡率，并根据呼吸死亡的日增长率量化了传染性估计。
从当地省级档案馆共检查了 52739 份个人死亡率记录。我们发现 1918 年 7 月至 9 月在利马存在初始轻度大流行波，在所有三个地点 1918 年 11 月至 1919 年 2 月期间发现呼吸死亡率同步严重大流行波，1920 年 1 月至 3 月在利马和 1920 年 7 月至 10 月在伊卡。1920 年伊基托斯没有复发大流行波。值得注意的是，利马在 1920 年的复发波期间经历了 1918-1920 年超额死亡影响的冲击，所有年龄组的所有原因超额死亡率均从 1918-1919 年增加到 1920 年。中年组在 1918-1919 年和 1920 年的大流行波中经历了相对于基线水平最高的超额死亡率影响。1918-1920 年大流行期间的累积超额死亡率在伊基托斯（2.9%）高于利马（1.6%）。利马的平均繁殖数估计在 1.3-1.5 之间。
我们确定了 1918 年 11 月至 1919 年 2 月在利马、伊基托斯和伊卡发生的同步严重呼吸过度死亡大流行波，随后在 1920 年发生异步复发波。拉丁美洲背景下对 1918 年流感大流行的定量研究累积数据证实了该大流行与高死亡率之间的关联。在拉丁美洲、非洲和亚洲研究较少的地区进一步开展历史研究，对于全面了解 1918 年大流行病毒的全球影响是必要的。
