INTRODUCTION
Over the past 2 decades, coronaviruses (COVs) have been associated with significant
disease outbreaks in East Asia and the Middle East. The severe acute respiratory
syndrome (SARS) and the Middle East respiratory syndrome (MERS) began to emerge in
2002 and 2012, respectively. Recently, a novel coronavirus, severe acute respiratory
syndrome coronavirus 2 (SARS-COV-2), causing coronavirus disease 2019 (COVID-19),
emerged in late 2019, and it has posed a global health threat, causing an ongoing
pandemic in many countries and territories. Health workers worldwide are currently
making efforts to control further disease outbreaks caused by the novel COV
(ORIGINALLY NAMED 2019-NCOV), which was first identified in Wuhan City, Hubei
Province, China, on 12 December 2019. On February 2020, the World Health
Organization (WHO) announced the official designation for the current COV-associated
disease to be COVID-19, caused by SARS-CoV-2. The primary cluster of patients was
found to be connected with the Huanan South China Seafood Market in Wuhan. COVs
belong to the family Corona viridae (SUBFAMILY CORONA VIRIDAE), the members of
which infect a broad route warrants the introduction of negative iècal viral nucleic acid
test results as one of the additional discharge criteria In laboratory-confirmed cases of
COVID-19. The COVID-19 pandemic does not have any novel factors, other than the
genetically unique pathogen and a further possible reservoir. The cause and the likely
future outcome are just repetitions of our previous interactions with fatal coronaviruses.
The only difference is the time of occurrence and the genetic distinctness of the pathogen
involved. Mutations on the RBI) of CoVs facilitated their capability of infecting newer
hosts, thereby expanding their reach to all corners of the world. This is a potential threat
to the health of both animals and humans. Advanced studies using Bayesian
phylogeographic reconstruction identified the most probable origin of SARS-CoV-2 as
the bat SARS-Iike coronavirus, circulating in the Rhinolophus bat family. Phylogenetic
analysis of 10 whole-genome sequences of SARS-CoV-2 showed that they are related to
two COVs of bat origin, namely, bat-SLCOVZC45 and bat-SL-C0VZXC21, which were
reported during 2018 in China (17). It was reported that SARS-CoV-2 had been
confirmed to use ACE2 as an entry receptor while exhibiting an RBI) similar fever,
caugh, and sputum. Hence the clinicians possibility of missed diagnosis. The early
transmission ability of SARS-CoV-2 was found to be similar to or slightly higher than
that of SARS-CoV, reflecting that it could be controlled despite moderate to high
transmissibility. Increasing reports of SARS-CoV-2 in sewage and wastewater warrants
the need for further investigation due to the possibility of fecal-oral transmission. SARS-
CoV-2 present in environmental compartments such as soil and water will finally end up
in the wastewater and sewage sludge of treatment plants. Therefore, we have to reevaluate
the current wastewater and sewage sludge treatment procedures and introduce advanced
techniques that are specific and effective against SARS-CoV-2. Since there is active
shedding of SARS-CoV-2 in the stool, the prevalence of infections in a large population
, can be studied using wastewater-based epidemiology. Recently, reverse transcription
quantitative PCR (RT-QPCR) was used to enumerate the copies of SARS-CoV-2 RNA
concentrated from wastewater collected from a wastewater treatment plant. The
calculated viral RNA copy numbers determine the number of infected individuals. The
trimeric SI locates itself on top of the trimeric S2 stalk. Recently, structural analyses of
the S proteins of COVID-19 have revealed 27 amino acid substitutions within a 1,273-
amino-acid stretch. Six substitutions are located in the RBI) (AMINO ACIDS 357 to
528), while four substitutions are in the RBM at the CTD of the Sl domain. Of note, no
amino acid change is seen in the RBM, which binds directly to the angiotensin-converting
enzyme-2 (ACE2) receptor in SARS-CoV (16, 46). At present, the main emphasis is
knowing how many differences would be required to change the host tropism. Sequence
comparison revealed 17 nonsynonymous changes between the early sequence of SARS-
CoV-2 and the later isolates of SARS-CoV. The changes were found scattered over the
genome of the virus, with nine substitutions in ORF1ab, ORF8 (4 substitutions), the spike
gene (3 substitutions), and ORF7a (single substitution). Notably, the same
nonsynonymous changes were found in a familial cluster, indicating that the viral
evolution happened during person-to-person transmission. Such adaptive evolution events
are frequent and constitute a constantly ongoing process once the virus spreads among
new hosts. Even though no functional changes occur in the virus associated with this
adaptive evolution, close monitoring of the viral Splits Tree phylogeny analysis. In the
unrooted phylogenetic tree of different betacoronaviruses based on the S protein, virus
sequences from different subgenera grouped into separate clusters, SARS-CoV-2
sequences from Wuhan and other countries exhibited a close relationship and appeared in
a single cluster (Fig. 1). The COVs from the subgenus Sarbecovirus appeared jointly in
Splits Tree and divided into three sub-clusters, namely, SARS-CoV-2, bat-SARS-
likeCOV (bat-SL-CoV), and SARS-CoV (FIG. 1). In the case of other subgenera, like
Merbecovirus, all of the sequences grouped in a single cluster, whereas in Embecovirus,
different species, comprised of canine respiratory COVs, bovine CoVs, equine COVs, and
human COV strain (OC43), grouped in a common cluster. Isolates in the subgenera
Nobecovorus and Hibecovirus were found to be placed separately away from other
reported SARS-CoVs but shared a bat origin.
CURRENT WORLDWIDE SCENARIO OF SARS-COV-2
This novel virus, SARS-CoV-2, comes under the subgenus Sarbecovirus of the
Orthocoronavirinae subfamily and is entirely different from the viruses We assessed the
nucleotide percent similarity using the MegAlign software program, where the similarity
between the novel SARS-CoV-2 isolates was in the range of 99.4% to 100%. Among the
other Serbecovirus COV sequences, the novel SARS-CoV2 sequences revealed the highest
similarity to batSL-CoV, with nucleotide percent identity ranges between 88.12 and 89.65%.
Meanwhile, earlier reported SARS-CoVs showed 70.6 to 74.9% similarity to SARS-CoV-2
Over the past 2 decades, coronaviruses (COVs) have been associated with significant
disease outbreaks in East Asia and the Middle East. The severe acute respiratory
syndrome (SARS) and the Middle East respiratory syndrome (MERS) began to emerge in
2002 and 2012, respectively. Recently, a novel coronavirus, severe acute respiratory
syndrome coronavirus 2 (SARS-COV-2), causing coronavirus disease 2019 (COVID-19),
emerged in late 2019, and it has posed a global health threat, causing an ongoing
pandemic in many countries and territories. Health workers worldwide are currently
making efforts to control further disease outbreaks caused by the novel COV
(ORIGINALLY NAMED 2019-NCOV), which was first identified in Wuhan City, Hubei
Province, China, on 12 December 2019. On February 2020, the World Health
Organization (WHO) announced the official designation for the current COV-associated
disease to be COVID-19, caused by SARS-CoV-2. The primary cluster of patients was
found to be connected with the Huanan South China Seafood Market in Wuhan. COVs
belong to the family Corona viridae (SUBFAMILY CORONA VIRIDAE), the members of
which infect a broad route warrants the introduction of negative iècal viral nucleic acid
test results as one of the additional discharge criteria In laboratory-confirmed cases of
COVID-19. The COVID-19 pandemic does not have any novel factors, other than the
genetically unique pathogen and a further possible reservoir. The cause and the likely
future outcome are just repetitions of our previous interactions with fatal coronaviruses.
The only difference is the time of occurrence and the genetic distinctness of the pathogen
involved. Mutations on the RBI) of CoVs facilitated their capability of infecting newer
hosts, thereby expanding their reach to all corners of the world. This is a potential threat
to the health of both animals and humans. Advanced studies using Bayesian
phylogeographic reconstruction identified the most probable origin of SARS-CoV-2 as
the bat SARS-Iike coronavirus, circulating in the Rhinolophus bat family. Phylogenetic
analysis of 10 whole-genome sequences of SARS-CoV-2 showed that they are related to
two COVs of bat origin, namely, bat-SLCOVZC45 and bat-SL-C0VZXC21, which were
reported during 2018 in China (17). It was reported that SARS-CoV-2 had been
confirmed to use ACE2 as an entry receptor while exhibiting an RBI) similar fever,
caugh, and sputum. Hence the clinicians possibility of missed diagnosis. The early
transmission ability of SARS-CoV-2 was found to be similar to or slightly higher than
that of SARS-CoV, reflecting that it could be controlled despite moderate to high
transmissibility. Increasing reports of SARS-CoV-2 in sewage and wastewater warrants
the need for further investigation due to the possibility of fecal-oral transmission. SARS-
CoV-2 present in environmental compartments such as soil and water will finally end up
in the wastewater and sewage sludge of treatment plants. Therefore, we have to reevaluate
the current wastewater and sewage sludge treatment procedures and introduce advanced
techniques that are specific and effective against SARS-CoV-2. Since there is active
shedding of SARS-CoV-2 in the stool, the prevalence of infections in a large population
, can be studied using wastewater-based epidemiology. Recently, reverse transcription
quantitative PCR (RT-QPCR) was used to enumerate the copies of SARS-CoV-2 RNA
concentrated from wastewater collected from a wastewater treatment plant. The
calculated viral RNA copy numbers determine the number of infected individuals. The
trimeric SI locates itself on top of the trimeric S2 stalk. Recently, structural analyses of
the S proteins of COVID-19 have revealed 27 amino acid substitutions within a 1,273-
amino-acid stretch. Six substitutions are located in the RBI) (AMINO ACIDS 357 to
528), while four substitutions are in the RBM at the CTD of the Sl domain. Of note, no
amino acid change is seen in the RBM, which binds directly to the angiotensin-converting
enzyme-2 (ACE2) receptor in SARS-CoV (16, 46). At present, the main emphasis is
knowing how many differences would be required to change the host tropism. Sequence
comparison revealed 17 nonsynonymous changes between the early sequence of SARS-
CoV-2 and the later isolates of SARS-CoV. The changes were found scattered over the
genome of the virus, with nine substitutions in ORF1ab, ORF8 (4 substitutions), the spike
gene (3 substitutions), and ORF7a (single substitution). Notably, the same
nonsynonymous changes were found in a familial cluster, indicating that the viral
evolution happened during person-to-person transmission. Such adaptive evolution events
are frequent and constitute a constantly ongoing process once the virus spreads among
new hosts. Even though no functional changes occur in the virus associated with this
adaptive evolution, close monitoring of the viral Splits Tree phylogeny analysis. In the
unrooted phylogenetic tree of different betacoronaviruses based on the S protein, virus
sequences from different subgenera grouped into separate clusters, SARS-CoV-2
sequences from Wuhan and other countries exhibited a close relationship and appeared in
a single cluster (Fig. 1). The COVs from the subgenus Sarbecovirus appeared jointly in
Splits Tree and divided into three sub-clusters, namely, SARS-CoV-2, bat-SARS-
likeCOV (bat-SL-CoV), and SARS-CoV (FIG. 1). In the case of other subgenera, like
Merbecovirus, all of the sequences grouped in a single cluster, whereas in Embecovirus,
different species, comprised of canine respiratory COVs, bovine CoVs, equine COVs, and
human COV strain (OC43), grouped in a common cluster. Isolates in the subgenera
Nobecovorus and Hibecovirus were found to be placed separately away from other
reported SARS-CoVs but shared a bat origin.
CURRENT WORLDWIDE SCENARIO OF SARS-COV-2
This novel virus, SARS-CoV-2, comes under the subgenus Sarbecovirus of the
Orthocoronavirinae subfamily and is entirely different from the viruses We assessed the
nucleotide percent similarity using the MegAlign software program, where the similarity
between the novel SARS-CoV-2 isolates was in the range of 99.4% to 100%. Among the
other Serbecovirus COV sequences, the novel SARS-CoV2 sequences revealed the highest
similarity to batSL-CoV, with nucleotide percent identity ranges between 88.12 and 89.65%.
Meanwhile, earlier reported SARS-CoVs showed 70.6 to 74.9% similarity to SARS-CoV-2
