Background

Vomiting is one way in which the body rids itself of harmful gastric contents rapidly. Whilst this process is generally beneficial for the emetic individual, it can pose significant infection control issues if they are infected with a highly communicable pathogen such as norovirus. It is not known how far norovirus could spread through vomiting while remaining viable, particularly in far-reaching droplets and splashes that might be missed during cleaning.

Aim

To identify the potential level of dissemination of viable norovirus after simulated vomiting.

Methods

This study used a system called ‘Vomiting Larry’ to simulate vomiting with infection medium containing the norovirus surrogate feline calicivirus (FCV) as a worst-case scenario for distribution and survival of viruses after simulated vomiting. Air and floor samples were taken after simulated vomiting, and analysed for viable virus via plaque assay. Analysis of covariance investigated differences in FCV concentration by sample volume and location.

Findings

Whilst viable virus was not isolated from any air samples taken after simulated vomiting, FCV concentrations of ≥10 plaque-forming units/mL were recovered from almost all samples taken from the floor (88/90). These included small droplets of fluid that travelled 3 m away from the vomiting system. There was evidence that FCV concentration depended on both sample volume and location.

Conclusion

This study suggests that norovirus can survive being ejected even within small far-reaching droplets at concentrations capable of eliciting infection. Such droplets could easily go unnoticed and be overlooked during cleaning, adding to the challenge of controlling norovirus outbreaks.

中文翻译：

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模拟呕吐后存活诺如病毒的潜在分布

背景

呕吐是身体迅速摆脱有害胃内容物的一种方式。尽管此过程通常对催吐者有益，但如果感染了高度传染性病原体（如诺如病毒），它可能会带来重大的感染控制问题。目前尚不知道诺如病毒可以通过呕吐传播多远，同时又保持活力，尤其是在清洁过程中可能遗漏的飞沫和溅水。

目的

以确定在模拟呕吐后传播活的诺如病毒的潜在水平。

方法

这项研究使用了一个名为“ Vomiting Larry”的系统，以含有诺如病毒替代猫杯状病毒（FCV）的感染培养基模拟呕吐，这是模拟呕吐后病毒分布和生存的最坏情况。在模拟呕吐后采集空气和地板样本，并通过噬菌斑分析对活病毒进行分析。协方差分析通过样本量和位置调查了FCV浓度的差异。

发现

尽管在模拟呕吐后未从任何空气样品中分离出活病毒，但从几乎所有从地板上采集的样品中，FCV浓度均≥10噬菌斑形成单位/ mL。其中包括离开呕吐系统3 m的小液滴。有证据表明，FCV浓度取决于样品量和位置。

结论

这项研究表明，诺如病毒即使能够在能够引起感染的浓度范围内的小液滴中弹射，也能幸免于难。这样的飞沫很容易被忽视，在清洁过程中容易被忽视，这增加了控制诺如病毒爆发的难度。