Human-Animal Interaction and the Emergence of SARS-CoV-2

Abstract

The COVID-19 pandemic has affected all sectors of society, from health and economics to socialization and travel. The level and extent of this impact are unprecedented. Although the cause of COVID-19 was quickly identified to be a new coronavirus (SARS-CoV-2), the world was poorly prepared for preventing its spread. One important pillar of preparedness is surveillance of the sources of emerging pathogens and responding appropriately to prevent their spread in the human population. The ever-increasing interaction between humans and animals is one leading factor in facilitating the emergence of new pathogens. In this viewpoint, we discuss the possibility of the zoonotic origin of SARS-CoV-2, highlight the importance of understanding human-animal interaction to improve preparedness for future outbreaks, and outline recommendations for prevention.

Keywords: COVID-19; SARS-CoV-1; emergence; human-animal interface; outbreak; pathogen; reservoir; transmission; virus; zoonosis.

Figure 1

The four-level model of pathogen emergence. Bushmeat production, poultry and livestock industries, and live-animal markets warrant frequent close animal-human and animal-animal contact and increase exposure to pathogens circulating in different species. Frequent exposure (level 1) can turn into a productive infection (level 2), given the necessary viral adaptation has taken place to make humans susceptible. By passaging through humans, the new virus may undergo further adaptation. Pandemic emergence necessitates an efficient human-to-human transmission for sustained propagation. Fast human movement across the globe amplifies the chain of transmission. Efforts should be directed at preventing level 1 (exposure) to significantly decrease the chances of pathogen emergence.