Department of ENT and Head & Neck Surgery, Bordeaux University Hospital, France; University Bordeaux, 33000 Bordeaux, France.
Department of ENT and Head & Neck Surgery, Bordeaux University Hospital, France.
Eur Ann Otorhinolaryngol Head Neck Dis. 2020 Sep;137(4):291-296. doi: 10.1016/j.anorl.2020.05.015. Epub 2020 May 31.
The influenza virus and SARS-CoV-2 cause trivial upper and severe lower respiratory infections (Influenza virus 290,000 to 650,000 deaths/year). These viruses come into contact with the airways either by direct projection, by secondary inhalation of airborne droplets, or by handling (fomites). The objective of this article is to clarify the mechanisms of production and penetration of droplets of secretions emitted during all expiratory phenomena likely to transport these viruses and come into contact with the respiratory mucosa. The droplets>5μm follow the laws of ballistics, those<5μm follow Brownian motion and remain suspended in the air. The aerosols of droplets are very heterogeneous whether the subject is healthy or sick. During an infectious period, not all droplets contain viral RNA. If these RNAs are detectable around patients, on surfaces, and in the ambient air at variable distances according to the studies (from 0.5m to beyond the patient's room), this is without prejudice to the infectious nature (viability) of the virus and the minimum infectious dose. There is a time lag between the patient's infectious period and that of RNA detection for both viruses. Subsequently, the inhaled particles must meet the laws of fluid dynamics (filtration) to settle in the respiratory tree. All of this partly explains the contagiousness and the clinical expression of these two viruses from the olfactory cleft to the alveoli.
流感病毒和 SARS-CoV-2 引起轻微的上呼吸道和严重的下呼吸道感染（流感病毒每年导致 29 万至 65 万人死亡）。这些病毒通过直接喷射、二次吸入空气传播的飞沫或经手接触（污染物）接触气道。本文的目的是阐明在所有可能传播这些病毒并与呼吸道黏膜接触的呼气现象中，分泌物飞沫产生和穿透的机制。>5μm 的飞沫遵循弹道定律，<5μm 的飞沫遵循布朗运动并悬浮在空气中。无论是健康人还是病人，飞沫气溶胶都是非常不均匀的。在感染期，并非所有飞沫都含有病毒 RNA。如果这些 RNA 在患者周围、表面以及周围空气中的不同距离（根据研究，从 0.5m 到超出患者房间）可检测到，这并不影响病毒的传染性（活力）和最小感染剂量。这两种病毒的患者传染性期和 RNA 检测期之间存在时间差。随后，吸入的颗粒必须符合流体动力学定律（过滤）才能在呼吸道中沉降。所有这些部分解释了这两种病毒从嗅裂到肺泡的传染性和临床表现。
