Hand-touching of contaminated surfaces is an established mode of infection transmission. However, the role of touch-mediated pathogen spread remains debatable, as frequently touched surfaces may exhibit low pathogen loads. To inform disease-prevention protocols, this study experimentally and theoretically investigated contamination in surface-touch networks as a function of touch behaviours and pathogen sources. Observation of four settings containing bacterial tracer particles showed that while most surfaces were rarely hand-touched, networks were formed by several high-touch ‘hubs’. Counterintuitively, heavy contamination was primarily exhibited by some rarely touched surfaces. A new model for simulating contaminant spread via surface touch was developed and validated using the experimental data. The simulation revealed that surface contaminants were typically distributed non-uniformly. In scenarios with one or several localised contaminant sources, high-touch surfaces typically exhibited moderate contamination. A network with a high density of touches or multiple contaminant sources exhibited accelerated spread to a uniform contaminant distribution, with high-touch surfaces quickly approaching moderate concentrations. Therefore, surface touching could either contaminate or “clean” surfaces. Undetectable or low pathogen concentrations on high-touch surfaces should not be interpreted as an absence of contaminated surfaces or of pathogen spread via surface touch.

中文翻译：

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具有中等污染水平的高接触表面是微生物传播的关键节点

手触摸受污染的表面是一种既定的感染传播方式。然而，触摸介导的病原体传播的作用仍然存在争议，因为经常接触的表面可能表现出低病原体负荷。为了为疾病预防方案提供信息，本研究通过实验和理论研究了表面触摸网络中污染与触摸行为和病原体来源的关系。对包含细菌示踪剂颗粒的四种设置的观察表明，虽然大多数表面很少被手触摸，但网络是由几个高接触的“集线器”形成的。与直觉相反，重度污染主要表现在一些很少接触的表面。开发了一种模拟污染物通过表面接触扩散的新模型，并使用实验数据进行了验证。模拟显示，表面污染物通常分布不均匀。在具有一个或多个局部污染源的情况下，高频接触表面通常表现出中度污染。具有高密度接触或多个污染源的网络表现出加速扩散至均匀的污染物分布，高频接触表面迅速接近中等浓度。因此，表面接触可能会污染或“清洁”表面。在高频接触表面上检测不到或病原体浓度低不应解释为没有受污染的表面或通过表面接触传播病原体。