The dynamics of measles in sub-Saharan Africa
The dynamics of measles in sub-Saharan Africa
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DOI：
10.1038/nature06509
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发表时间：
2008-02-07
期刊：
影响因子：
64.8
通讯作者：
Grenfell, Bryan T.
中科院分区：
文献类型：
--
作者：
Ferrari, Matthew J.;Grais, Rebecca F.;Grenfell, Bryan T.
虽然疫苗接种在世界部分地区几乎消灭了麻疹，但在萨赫勒地区一些高出生率国家，麻疹仍然是一个主要杀手。根据工业化国家的麻疹动态，高出生率地区应每年定期发生流行病。然而，在这里，我们表明，尼日尔的麻疹流行是高度偶发性的，特别是在首都尼亚美。模型表明，这种变异性产生于强大的季节性传播-产生高振幅的流行病-在确定性动力学的混沌域。在实践中，这会导致频繁的随机衰落，并伴随着不规则的大规模流行。集合种群模型说明了疫苗覆盖率的增加，但仍低于当地消除阈值，可能会导致在高度季节性的情况下，重大疫情的变化越来越大。这种不稳定的动态强调了控制战略的重要性，即解决易感个体的积累问题，以及在大规模疫情发生时努力减轻其影响。
Although vaccination has almost eliminated measles in parts of the world, the disease remains a major killer in some high birth rate countries of the Sahel. On the basis of measles dynamics for industrialized countries, high birth rate regions should experience regular annual epidemics. Here, however, we show that measles epidemics in Niger are highly episodic, particularly in the capital Niamey. Models demonstrate that this variability arises from powerful seasonality in transmission - generating high amplitude epidemics - within the chaotic domain of deterministic dynamics. In practice, this leads to frequent stochastic fadeouts, interspersed with irregular, large epidemics. A metapopulation model illustrates how increased vaccine coverage, but still below the local elimination threshold, could lead to increasingly variable major outbreaks in highly seasonally forced contexts. Such erratic dynamics emphasize the importance both of control strategies that address build- up of susceptible individuals and efforts to mitigate the impact of large outbreaks when they occur.