咳嗽飞沫核携带病毒在病房机械通风条件下经空气传播的人工模拟技术研究

Artificial simulation research on cough induced virus droplet nuclei transmission in air in mechanically ventilated hospital ward

目的建立评估呼吸道传染病经空气传播能力的现场试验研究方法。方法在典型机械通风病房内雾化含有大肠埃希菌噬菌体的模拟唾液,雾化液滴与咳嗽飞沫具有类似粒径分布的液滴谱系,检测空气中不同粒径液滴核数量并估算其初始液滴的几何尺寸,计算液滴核初始携带的噬菌体数量,通过采集空气生物标本获得液滴核内噬菌体的实际存活量,比较两组数据获得液滴核携带的噬菌体在病房空气中的存活函数。结果在表面蒸发作用下,模拟唾液雾化液滴所携带的存活噬菌体数量快速损失约83%,在360 s的检测时间段内液滴核内的噬菌体平均存活函数稳定在17%且不随检测点变化,室内空气中液滴核数量的衰减率与空气生物标本中噬菌体数量的衰减率一致,记录雾化液滴核数量即可推算病房空间生物暴露水平。结论咳嗽飞沫核携带病毒在空气中传播的人工模拟技术,可用于评估呼吸道传染病经空气传播能力的现场试验研究。

Objective To establish a field experimental research method to evaluate air transmission ability of respiratory infectious diseases.Methods The simulated saliva containing Escherichia coli phage was atomized in a typical mechanical ventilation ward,atomized droplets and cough droplets had droplet spectrum of similar droplet size distribution,the number of droplet nuclei with different particle size in air was detected,geometrical dimension of the initial droplet was estimated,the number of phages initially carried by droplet nuclei was calculated,the actual survival of phages in the droplet nuclei was obtained by collecting biological specimen of air,survival function of phage carried by droplet nuclei in ward air between two groups of data was compared.Results The number of viable phages carried by simulated atomized saliva droplets rapidly lost about 83%under surface evaporation,the average survival function of phage in the droplet nuclei was stable at 17%and did not change with the detection point during the detection period of 360 seconds,attenuation rate of the number of droplet nuclei in indoor air was consistent with that of phages in air specimens,biological exposure level of the ward space can be calculated by recording the number of atomized droplet nuclei.Conclusion The artificial simulation technology of virus transmission in the air induced by cough droplet nuclei can be applied to evaluate field experiment of the air transmission ability of respiratory infectious diseases.