Understanding SARS-CoV-2 features of infectivity, aggressiveness, and transmissibility: An insect-vector theory for SARS-CoV-2 dissemination

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a ribonucleic acid–based (RNA-based) lineage B β-coronavirus characterized by 10-20 times higher infectivity and transmissibility even across species than previous coronaviruses. The significant infectivity rate of SARS-CoV-2 is due to its different host cell entry mechanisms that are mainly via angiotensin-converting enzyme 2 (ACE2) receptors contrasting earlier coronaviruses that used mainly the endosomal route. Due to the widespread distribution of ACE2 receptors throughout our body, various routes of infectivity are possible, highlighting the necessity of employing multiple forms of protection besides face masks to limit inter-human transmissibility. SARS-CoV-2 exhibits other remarkable features such as the ability to escape the immune system repeated genomic mutations that make it difficult to design a vaccine to address all viral strains and form huge host cell syncytia leading to massive tissue destruction. If we accept SARS-CoV-2 primary reservoir from bats, we should investigate the routes of viral inter-species propagation. In this article, a new theory is proposed- that the dissemination of the virus from the bats to other species and humans could have been possible via an insect vector, as insects possess significant amounts of both ACE2 receptors and a disintegrin and metalloprotease 17 (ADAM-17) enzymes that are essential for virus infectivity. .

Keywords

• SARS-CoV-2, ACE2, ADAM-17, COVID-19, Infectivity, Insect Vector, Romania