Temporal variations in the effective reproduction number of the 2014 west Africa ebola outbreak.
Temporal variations in the effective reproduction number of the 2014 west Africa ebola outbreak.
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DOI：
10.1371/currents.outbreaks.9e4c4294ec8ce1adad283172b16bc908
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发表时间：
2014-09-18
期刊：
影响因子：
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通讯作者：
Castillo-Chavez, Carlos
中科院分区：
文献类型：
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作者：
Towers, Sherry;Patterson-Lomba, Oscar;Castillo-Chavez, Carlos
2014年西非埃博拉病毒病（EVD）疫情迅速发展，无论是在感染人数还是在地理分布方面，都是历史上最大的疫情。高发病率和死亡率激发了个人、区域和国家各级对疫情的应对战略。提供实时评估传播动态变化的方法对于了解这些适应性干预措施如何影响疫情传播至关重要。方法在这项分析中，我们使用几内亚、塞拉利昂和利比里亚截至2014年9月8日的EVD病例时间序列，并采用新的方法，使用指数曲线分段拟合疫情数据，估计新病例指数上升率在疫情期间的变化。结果我们发现，在利比里亚和几内亚，有效繁殖数上升，而不是下降，在疫情蔓延到人口密集的城市，并在国家的几个地区实施强制检疫的时间，这可能表明，强制检疫可能不是一个有效的控制措施。如果没有采取有效的控制措施，并且目前的新病例指数增长率继续下去，我们预测9月下旬西非将出现4400例新埃博拉病例，95%置信水平上限为6800例新病例。
Background The rapidly evolving 2014 Ebola virus disease (EVD) outbreak in West Africa is the largest documented in history, both in terms of the number of people infected and in the geographic spread. The high morbidity and mortality have inspired response strategies to the outbreak at the individual, regional, and national levels. Methods to provide real-time assessment of changing transmission dynamics are critical to the understanding of how these adaptive intervention measures have affected the spread of the outbreak. Methods In this analysis, we use the time series of EVD cases in Guinea, Sierra Leone, and Liberia up to September 8, 2014, and employ novel methodology to estimate how the rate of exponential rise of new cases has changed over the outbreak using piecewise fits of exponential curves to the outbreak data. Results We find that for Liberia and Guinea, the effective reproduction number rose, rather than fell, around the time that the outbreak spread to densely populated cities, and enforced quarantine was imposed on several regions in the countries; this may indicate that enforced quarantine may not be an effective control measure. Conclusions If effective control measures are not put in place, and the current rate of exponential rise of new cases continues, we predict 4400 new Ebola cases in West Africa during the last half of the month of September, with an upper 95% confidence level of 6800 new cases.