Human CoVs (hCoVs) were discovered in people suffering from the
common cold during the early 1960s. This family is comprised of four well-known
genera, viz. α-CoV, β-CoV, γ-CoV, and ∆-CoV. Mammals, including humans, pigs,
cats, and bats, may be infected by α-CoV and or β-CoV. γ-CoV mainly affects
avifauna, whereas ∆-CoVs affect both birds and mammals. The coronavirus (CoV)
outbreak has caused great devastation globally. CoVs are positive-sense, nonsegmented single-stranded RNA viruses of the order nidovirales and the family
Coronaviridae. Deep sequencing examination of lower respiratory tract pathological
studies on affected people revealed the presence of a new coronavirus strain, which was
termed SARS-CoV-2. Four structural proteins, viz. envelope protein (E), membrane
protein (M), nucleocapsid protein (N), and spike protein (S) have also been determined.
Following the very initial reports of the novel severe acute respiratory syndrome
(SARS) coronavirus back in late 2019 from Wuhan, China, a plethora of research
attempts arose on how SARS-CoV-2 made its entry into humans. There is still a
difference in ideology for its laboratory escape or the zoonotic spread, but the exact
phenomenon is not known yet. Completing a thorough review, the studies suggest that
the virus's origin is more complicated than previously known.
Keywords: HCoVs, α-coronavirus, Single-stranded RNA, SARS, Wuhan.
