Fluid dynamic insights into virus deposition and transport in the deep lung
Year: 2021
Type: preprint
Abstract: Respiratory viruses, like SARS-CoV-2, are primarily transmitted through the airborne route by respiratory droplets. The inhaled droplets are deposited in the upper respiratory tract mucus layer, where the virus infects and replicates in the nasopharyngeal epithelial cells leading to rapid progression of the infection. Some patients may develop severe pneumonia and acute respiratory distress syndrome when the distal alveolar region is involved by progressive disease. The mechanism by which the virus is transported from the pharynx to the alveoli is still not clear. This work demonstrates a plausible and clinically supported pathway for deep lung infection that involves inhalation of self-aerosolized droplets from the pharyngeal or upper respiratory tract mucus. A coupled mathematical model of droplet and virus transport, within a Weibel-like lung geometry, is solved computationally to identify conditions for the transport of virus-laden droplets from the pharyngeal region to the deep lungs. Specifically, the model predicts, in agreement with clinical observations, that the infection can develop in the alveoli in 1 to 18 days. However, this requires continuous inhalation of virus-laden droplets, from the upper airways, for that duration. Continuous exposure to airborne virus-laden droplets from the environment is unlikely for such a long duration. This leads to inhalation of self-aerosolized droplets as one of the most likely pathways for the upper respiratory infection to transmit to the deep lungs. This study also identifies the conditions conducive for virus washout from the lungs, which plays an important role in determining the severity of an infection.
Source: arXiv (Cornell University)
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W3107940521