“呕吐机”显示诺如病毒可通过空气传播

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我们并不缺辞藻来形容呕吐，但令人惊讶的是，对于呕吐背后的物理学以及反流后感染如何传播我们都知之甚少。

之前有零散证据表明，病毒颗粒，特别是美国急性肠胃炎的元凶诺如病毒，可能会在呕吐的过程中通过空气传播。但位于罗利的北卡罗莱纳州立大学的食品病毒学家Lee-Ann Jaykus说：“从来没有人通过实验模型证实该病毒可以通过呕吐被雾化。”为了确认这一点，Jaykus和她的团队造了一个小型“呕吐机”，这是一个四分之一比例的人体消化系统模型，里面完整配备了人造胃、食道和口腔。这个机器被设计成可以模仿所有现有能搅翻人体的压力和体积，然后研究人员将一种叫做MS2的病毒（它的大小、形状和结构同诺如病毒相似，但对人体无害）植入它的“胃”液中。他们在一个密室里运作这台机器，密室同时与一个传感器相连，可以检测到任何漂浮的病毒颗粒。



该研究团队今天在PLOS ONE上报告说，他们采用了各种不同的压力、呕吐物的粘度、体积和病毒浓度，结果发现每一种情况下都可以在空气中检测到MS2病毒颗粒。如预料的一样，当更多的MS2被加到胃中，更多的病毒颗粒也被雾化，并且呕吐粘度和系统压力被证明均为重要的变量。大多数病毒——超过13,000个颗粒——被观察到带有高初始病毒浓度和高粘度呕吐物。


研究团队表示，这个结果证实了那些零散报告的可信度，即在一阵呕吐后，诺如病毒会通过空气进行传播。


来源：生物360

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Aerosolization of a Human Norovirus Surrogate, Bacteriophage MS2, during Simulated Vomiting

Grace Tung-Thompson , Dominic A. Libera , Kenneth L. Koch, Francis L. de los Reyes III  , Lee-Ann Jaykus

Abstract

Human noroviruses (NoV) are the leading cause of acute gastroenteritis worldwide. Epidemiological studies of outbreaks have suggested that vomiting facilitates transmission of human NoV, but there have been no laboratory-based studies characterizing the degree of NoV release during a vomiting event. The purpose of this work was to demonstrate that virus aerosolization occurs in a simulated vomiting event, and to estimate the amount of virus that is released in those aerosols. A simulated vomiting device was constructed at one-quarter scale of the human body following similitude principles. Simulated vomitus matrices at low (6.24 mPa*s) and high (177.5 mPa*s) viscosities were inoculated with low (108 PFU/mL) and high (1010 PFU/mL) concentrations of bacteriophage MS2 and placed in the artificial “stomach” of the device, which was then subjected to scaled physiologically relevant pressures associated with vomiting. Bio aerosols were captured using an SKC Biosampler. In low viscosity artificial vomitus, there were notable differences between recovered aerosolized MS2 as a function of pressure (i.e., greater aerosolization with increased pressure), although this was not always statistically significant. This relationship disappeared when using high viscosity simulated vomitus. The amount of MS2 aerosolized as a percent of total virus “vomited” ranged from 7.2 x 10-5 to 2.67 x 10-2 (which corresponded to a range of 36 to 13,350 PFU total). To our knowledge, this is the first study to document and measure aerosolization of a NoV surrogate in a similitude-based physical model. This has implications for better understanding the transmission dynamics of human NoV and for risk modeling purposes, both of which can help in designing effective infection control measures.

http://journals.plos.org/plosone ... ournal.pone.0134277