Heterogeneous shedding of Escherichia coli O157 in cattle and its implications for control
Heterogeneous shedding of Escherichia coli O157 in cattle and its implications for control
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DOI：
10.1073/pnas.0503776103
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发表时间：
2006-01-17
影响因子：
11.1
通讯作者：
Woolhouse, MEJ
中科院分区：
文献类型：
--
作者：
Matthews, L;Low, JC;Woolhouse, MEJ
确定宿主内和宿主间感染性变异的相对重要性以及这些异质性对传染性病原体传播动力学的影响，可以有效地确定控制措施的目标。牛是人畜共患病病原体大肠杆菌O 157的主要储存宿主，已知其细菌脱落密度具有高度异质性。通过将细菌计数与传染性相关联，并将动态流行病学模型与苏格兰养牛场横断面调查的流行率数据相拟合，我们确定了一个强大的模式：大约80%的传播来自20%最具传染性的个体。我们在一系列关于感染动态中宿主内和宿主间变异性的假设下研究了潜在的控制方案。我们的研究结果表明，通过采取针对性措施，旨在预防总体感染性最高的5%个体的感染，可以将牛群内基本繁殖率R-0降至< 1。或者，旨在减少细菌携带的干预措施（如接种疫苗或使用益生菌）可以通过防止在对应于观察到的计数范围的前几个百分比的浓度下携带细菌来显著降低R-0。我们的结论是，更好地了解细菌携带异质性的原因可能会导致高效的控制措施，以减少流行的E。coli O157。
Identification of the relative importance of within- and between-host variability in infectiousness and the impact of these heterogeneities on the transmission dynamics of infectious agents can enable efficient targeting of control measures. Cattle, a major reservoir host for the zoonotic pathogen Escherichia coli O157, are known to exhibit a high degree of heterogeneity in bacterial shedding densities. By relating bacterial count to infectiousness and fitting dynamic epidemiological models to prevalence data from a cross-sectional survey of cattle farms in Scotland, we identify a robust pattern: approximate to 80% of the transmission arises from the 20% most infectious individuals. We examine potential control options under a range of assumptions about within- and between-host variability in infection dynamics. Our results show that the within-herd basic reproduction ratio, R-0, could be reduced to < 1 with targeted measures aimed at preventing infection in the 5% of individuals with the highest overall infectiousness. Alternatively, interventions such as vaccination or the use of probiotics that aim to reduce bacterial carriage could produce dramatic reductions in R-0 by preventing carriage at concentrations corresponding to the top few percent of the observed range of counts. We conclude that a greater understanding of the cause of the heterogeneity in bacterial carriage could lead to highly efficient control measures to reduce the prevalence of E. coli O157.