What we know and what we need to know about the origin of SARS-CoV-2

Abstract

Since the appearance of the first cases of COVID-19 in 2019, an unprecedented number of documents on that disease have been published in a short space of time. The current available information covers a large number of topics related with COVID-19 and/or the coronavirus (SARS-CoV-2) responsible of the disease. However, only a limited number of publications have been focused on a controversial issue: the origin of the SARS-CoV-2. In this paper, the scientific literature on the origin of SARS-CoV-2 has been reviewed. Documents published during 2020 and 2021 (January 1-July 19) in journals that are indexed in PubMed and/or Scopus has been considered. The revised studies were grouped according to these two potential origins: natural and unnatural. The analyses of the conclusions of the different documents here assessed show that even considering the zoonotic hypothesis as the most likely, with bats and pangolins being possibly in the origin of the coronavirus, today's date the intermediate source species of SARS-CoV-2 has not been confirmed yet. On the other hand, some researchers point to an unnatural origin of this coronavirus, but their conclusions are not strongly supported by a clear scientific evidence. Given the tremendous severity of the current pandemic, investigations to establish clearly and definitively the origin of SARS-CoV-2, are basic and essential in order to prevent potential future pandemics of similar nature.

Positive association between outdoor air pollution and the incidence and severity of COVID-19. A review of the recent scientific evidences

“… Barnett-Itzhaki and Levi, 2021 , Domingo, 2021a , Domingo, 2021b , Hoang and Tran, 2021 , Mehmood et al , Mendy et al, 202 , Zhou et al, …”

Elucidating the role of environmental management of forests, air quality, solid waste and wastewater on the dissemination of SARS-CoV-2

“…Even though research about animal reservoir of SARS-CoV-2 is evolving and has not been validated, available studies are pointing towards zoonotic natural origins of SARS-CoV-2 with horseshoe bats (Rhinolophus ) as plausible natural reservoir and pangolins as an intermediate host of the coronavirus ( Domingo, 2021 ; Jorwal et al, 2020 ; Zhang and Holmes, 2020 ). Different bats of the genus Rhinolophus were reported to host viruses phylogenetically similar to SARS-CoV-2 in China ( Rhinolophus affinis, Rhinolophus pusillus and Rhinolophus malayanus ), Cambodia ( Rhinolophus shameli ), Japan ( Rhinolophus cornutus ) and Thailand ( Rhinolophus acuminatus ) ( Murakami et al, 2020 ; Zhou et al, 2020 ; Zhou et al, 2021 b; Wacharapluesadee et al, 2021 ).…”

“…Another plausible effect from exposure to outdoor air pollutants could be increased spread of COVID-19 by decreased immune response, lung damage and overexpression of angiotensin-converting enzyme 2 (ACE2), leading to more severe and lethal forms of COVID-19, as well as delays/complications in the recovery of the patients ( Alifano et al, 2020 ; Bourdrel et al, 2020; Comunian et al, 2020 ; Paital and Agrawal, 2020 ; Marques and Domingo, 2021 ). Upregulation of ACE2 by PM 10 was found in human alveolar A549 and human respiratory epithelial cells in a non- peer reviewed study ( Miyashita et al, 2020 ).…”

“…The importance of the role of environmental management in disease control was clearly evidenced in previous infectious disease outbreaks especially for vector borne diseases such as malaria and dengue fever ( Utzinger et al, 2001 ; Toledo et al, 2011 ). The presumed emergence of COVID-19 from zoonotic natural host in conjunction with other increasingly frequent zoonotic diseases point towards the unsustainable management of forests and decline of biodiversity due to human encroachment in pristine natural habitats ( Domingo, 2021 ; Jorwal et al, 2020 ; WWF, 2021a; WWF, 2021b). Since the 1980s, a significant increase in the number and diversity of infectious zoonotic disease outbreaks have been observed and 700,000 viruses were estimated from high-risk viral families which pose zoonotic potential, indicating the possibility of recurrence of similar incidents (Smith et al,2014; Wigginton and Boehm, 2020 ).…”

SARS-CoV-2 and the Host Cell: A Tale of Interactions

“…Within these unknown intermediate hosts, SARS-CoV-2 acquired some or all the mutations needed for efficient transmission and replication into humans (9). In conclusion, although the molecular and phylogenetic analyses indicate the zoonotic hypothesis as the most likely, the origin and intermediate host species of SARS-CoV-2 remain uncertain and an unnatural origin of this coronavirus cannot be formally excluded [for a detailed review, see (10)].…”