Introduction to SARS-COV-2
SARS-CoV-2, which causes COVID-19 illness, represents the seventh member
of the coronavirus family that infects humans and has been classified
under the orthocoronavirinae subfamily. The SARS-CoV-2 forms a clade
within the subgenus sarbecovirus (Zhu et
al., 2020). Based on the genetic sequence identity and the phylogenetic
reports, SARS-CoV-2 is sufficiently different from SARS-CoV, and it can
thus be considered as a new betacoronavirus that infects humans. The
SARS-CoV-2 most likely developed from the bat origin coronaviruses.
Another piece of evidence that supports the SARS-CoV-2 is of bat origin
is the existence of a high degree of homology of the
angiotensin-converting enzyme 2 (ACE2) receptor from a diversity of
animal species, thus implicating these animal species as possible
intermediate hosts or animal models for COVID-19 infections
(Wan, Shang, Graham, Baric & Li, 2020).
Moreover, these viruses have a single, intact open reading frame on gene
8, which is a further indicator of bat-origin CoVs
(Ren et al., 2020). However, the amino
acid sequence of the tentative receptor-binding domain resembles that of
SARS-CoV, indicating that these viruses might use the same receptor
(Ren et al., 2020). The susceptibility to
the infection with SARS-COV-2 and disease severity varied amongst
individuals factoring age, sex, and health conditions. The SARS-COV-2
infection also varies based on symptomatic and asymptomatic infections,
where the symptomatic include mild and severe infections. Thus, it is
the rationale that the treatment/disease management of COVID-19 illness
should be applied, taking in mind the mentioned groups of people and
infection categories. Here, we discuss the epidemiology of the COVID-19
illness based on patient groups and the severity of the infection. Also,
we discuss the role of the cellular receptors and co-receptors in virus
infectivity, the co-morbidity with cardio-metabolic syndromes, the
overlap between cardio-metabolic treatments and COVID-19 infection, and
the potential pre and post exposure therapeutics, including those in
clinical trials to treat the COVID-19 illness.