May SARS-CoV-2 Diffusion Be Favored by Alkaline Aerosols and Ammonia Emissions?

Maurizio Manigrasso,Matteo Vitali,Carmela Protano,Pasquale Avino,Ettore Guerriero

doi:10.3390/atmos11090995

Abstract

Ammonia is a common factor linking air in bat caves and air pollution in the proximity of agricultural fields treated with livestock farming sewage and slaughterhouses, where important clusters of COVID-19 have recently been reported all over the world. Such a commonality has a further connection with the known behavior of some viruses of the coronavirus family, such as the murine hepatitis virus, whose spike glycoprotein (S) can be triggered to a membrane-binding conformation at pH 8.0. Within the airborne route of virus transmission, with particular relevance for crowded and enclosed environments, these observations have prompted a hypothesis that may represent a contributing cause to interpret the geographical variability of the virus diffusion and the surging rise of COVID-19 cases in slaughterhouses all over the world. The hypothesis is that, in these environments, the SARS-CoV-2 S protein may find on a fraction of the airborne particles an alkaline pH, favorable to trigger the conformational changes, needed to induce the fusion of the viral envelope with the plasma membrane of the target cells.

Highlights

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; initially temporarily called 2019 novel coronavirus or 2019-nCoV), made its early appearance in China at the end of 2019
SARS-CoV-2 as a Public Health Emergency of International Concern [4] and, on 11 February 2020, the World Health Organization (WHO) announced that the respiratory disease had been officially called COVID-19; the same agency, given the severity of the infection and the level of spread, on 11 March 2020 declared that the outbreak of COVID-19 could be considered a pandemic [5]
Wu et al [24] showed that an increase of 1 μg m−3 in long-term exposure to PM2.5 is associated with an 8% increase in the COVID-19 death rate

Summary

Introduction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; initially temporarily called 2019 novel coronavirus or 2019-nCoV), made its early appearance in China at the end of 2019. The paradigm proposed is that the chronic exposure to atmospheric pollutants, by challenging cardiovascular and respiratory health, impairs the host defense ability against virus infections Along these lines, Wu et al [24] showed that an increase of 1 μg m−3 in long-term exposure to PM2.5 is associated with an 8% increase in the COVID-19 death rate. The authors stressed the relevance of this route of infection, observing that SARS-CoV-1 did spread in the air This mechanism may be all the more relevant, considering that such smaller virus-bearing particles may, in some cases, derive from the droplet evaporation process, and directly from exhaled air. On this route of transmission, based on some relevant features of SARS-Cov-2, of the coronavirus family and of atmospheric PM, this paper proposes a hypothesis on the interaction of SARS-Cov-2 and airborne particles

Relevant Issues on the Acidity of Atmospheric Aerosol

Relevant Issues about SARS-CoV-2

Findings

Hypothesis on the Interaction of SARS-CoV-2 with Airborne Particles

Conclusions