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1/
NIH Study: COVID-19 severity could depend on route of infection: Infection through inhaling #Airborne virus could lead to more severe disease than infection from fomites (contact w/ contaminated objects.) To test it, hamsters were infected via the different routes. 1/7
NIH Study: COVID-19 severity could depend on route of infection: Infection through inhaling #Airborne virus could lead to more severe disease than infection from fomites (contact w/ contaminated objects.) To test it, hamsters were infected via the different routes. 1/7
2/Intranasal (I.N) and aerosol inoculation caused more severe respiratory pathology, higher viral loads and increased weight loss. Fomite exposure led to milder disease. Here's weight loss
Black lines are control animals in each group. 2/7
Black lines are control animals in each group. 2/7
3/Also, compared to intranasal exposure, aerosol exposed
hamsters had higher viral load in trachea and lung "suggesting aerosol exposure more efficiently deposits viral droplet nuclei in the lower respiratory system" Preprint: 3/7 https://www.biorxiv.org/content/10.1101/2020.12.28.424565v1
hamsters had higher viral load in trachea and lung "suggesting aerosol exposure more efficiently deposits viral droplet nuclei in the lower respiratory system" Preprint: 3/7 https://www.biorxiv.org/content/10.1101/2020.12.28.424565v1
4/In humans, larger aerosols deposit in upper throat, nose, & tracheobronchial region of the lung. Medium-sized aerosols mostly deposit in small airways further down. The really small aerosols <1 μm can penetrate all the way to the alveoli - the basic units for gas exchange. 4/7
5/In contrast to other mode of transmission where virus hits nasal cavity and finds its way into lungs, aerosols can directly reach alveolar region and attack alveolar cells that produce Pulmonary Surfactant. PS is needed to lower surface tension & prevent alveoli collapse. 5/7
6/Loss of these alveolar cells results in alveolar instability, lung flooding, and respiratory failure - Acute Respiratory Distress Syndrome (ARDS). ARDS causes further damage through a hyperactive immune response of neutrophils and cytokines that damage alveoli even more. 6/7
7/Viewing transmission through the lens of bioaerosol mechanics highlights the need for mitigation approaches such as ventilation and other measures, and new therapeutic interventions, like surfactant therapy to alleviate ARDS symptoms. 7/7 https://pubs.acs.org/doi/10.1021/acsnano.0c08484
