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.