Shedding of norovirus in symptomatic and asymptomatic infections
Shedding of norovirus in symptomatic and asymptomatic infections
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DOI：
10.1017/s095026881400274x
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发表时间：
2015-06-01
影响因子：
4.2
通讯作者：
Koopmans, M. P. G.
中科院分区：
文献类型：
--
作者：
Teunis, P. F. M.;Sukhrie, F. H. A.;Koopmans, M. P. G.
诺如病毒是急性传染性胃肠炎最常见的原因，在医院和疗养院等拥挤的环境中很难控制。传播依赖于感染者口服摄入沉积在环境中的病毒。来自志愿者研究的数据表明，粪便中的病毒浓度变化很大，但缺乏对排毒时间过程及其个体差异的系统研究。本文量化了诺如病毒在102名受试者（包括无症状散毒者）中的散毒，并使用纵向模型来概括散毒模式。加强监测，研究诺如病毒在医院爆发的传播，产生了相当数量的粪便样本的症状和无症状的散毒者，无论是从病人和工作人员。通过实时PCR测定诺如病毒浓度。在多水平贝叶斯框架下，对脱落数据拟合了定量动态模型，以研究脱落的时间过程及其变化。结果表明，无症状受试者的排毒与有症状感染者相似，两者在峰值水平（平均10（5）-10（9）/g粪便）以及排毒持续时间（平均8-60天）方面均显示出相当大的差异。病人似乎比工作人员排出更多的病毒，持续时间略长，但差异太小，不显着。在同等脱落的情况下，有症状的病例对传播的贡献更大，这一定是由于它们传播这些病毒的效率更高。本研究的结果将有助于风险研究，需要量化的病毒在环境中的沉积。
Norovirus is the most frequent cause of acute infectious gastroenteritis and it is difficult to control in crowded environments like hospitals and nursing homes. Transmission depends on oral intake of virus deposited in the environment by infectious subjects. Data from volunteer studies indicate that virus concentrations in stool are highly variable, but systematic studies of the time-course of shedding and its individual variation are lacking. This paper quantifies norovirus shedding in a large population of 102 subjects, including asymptomatic shedders, and uses a longitudinal model to generalize shedding patterns. Enhanced surveillance for studies of transmission of norovirus in hospital outbreaks has yielded a considerable number of faecal samples from symptomatic and asymptomatic shedders, both from patients and staff. Norovirus concentrations were determined by real-time PCR. A quantitative dynamic model was fitted to the shedding data, in a multilevel Bayesian framework, to study the time-course of shedding and its variation. The results indicate that shedding in asymptomatic subjects is similar to that in symptomatic infections, both showing considerable variation in peak levels (average 10(5)-10(9) /g faeces) as well as duration of virus shedding (average 8-60 days). Patients appear to shed higher numbers of virus than staff, for slightly longer durations, but the differences are too small to be significant. Given equal shedding, the greater contribution of symptomatic cases to transmission must be caused by their higher efficiency in spreading these viruses. The results of this study will be helpful for risk studies that need to quantify the deposition of virus in the environment.