How pox viruses spread? – A mechanophysiological model for inhaled airborne transmission of variola and mpox viruses

Pathogens from the Orthopoxvirus family can often transmit through inhalation of virus-laden aerosols and droplets, with initial infection occurring along the respiratory pathway. To better understand how the intra-airway flow physics would impact disease pathology, we have developed an experimentally validated physiological fluid dynamics model that simulates the inhalation process of Orthopoxvirus-embedded particulates, specifically the variola virus responsible for smallpox, using high-fidelity Large Eddy Simulations of airflow and particle movement within anatomically reconstructed airway domains. By integrating these simulations with viral concentrations and immune factors, we have estimated that the critical exposure durations range from 1 to 19 hours for smallpox, consistent with the established literature. Subsequently extending this inhalation physics-guided approach to the mpox virus, a circulating pathogen of the same genus, reveals a critical exposure window of 24 to 40 hours for onset of infection through inhalation of pathogenic particulates. Although the predicted mpox window is clearly longer compared to that for smallpox, it still is suggestive of the possibility of inhaled airborne transmission during prolonged exposure.