Does SARS-CoV-2 have any subtypes, and if so what are they?

The S glycoprotein of coronaviruses is important for viral entry and pathogenesis with most variable sequences. Therefore, we analyzed the S gene sequences of SARS-CoV-2 to better understand the antigenicity and immunogenicity of this virus in this study. In phylogenetic analysis, two subtypes (SARS-CoV-2a and -b) were confirmed within SARS-CoV-2 strains. These two subtypes were divided by a novel synonymous mutation of D614G. This may play a crucial role in the evolution of SARS-CoV-2 to evade the host immune system. The region containing this mutation point was confirmed as a B-cell epitope located in the S1 domain, and SARS-CoV-2b strains exhibited severe reduced antigenic indexes compared to SARS-CoV-2a in this area. This may allow these two subtypes to have different antigenicity. If the two subtypes have different serological characteristics, a vaccine for both subtypes will be more effective to prevent COVID-19. Thus, further study is urgently required to confirm the antigenicity of these two subtypes.

A Novel Synonymous Mutation of SARS-CoV-2: Is This Possible to Affect Their Antigenicity and Immunogenicity?

Since its emergence in Wuhan, China, in December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected ≈6 million persons worldwide. As SARS-CoV-2 spreads across the planet, we explored the range of human cells that can be infected by this virus. We isolated SARS-CoV-2 from 2 infected patients in Toronto, Canada; determined the genomic sequences; and identified single-nucleotide changes in representative populations of our virus stocks. We also tested a wide range of human immune cells for productive infection with SARS-CoV-2. We confirm that human primary peripheral blood mononuclear cells are not permissive for SARS-CoV-2. As SARS-CoV-2 continues to spread globally, it is essential to monitor single-nucleotide polymorphisms in the virus and to continue to isolate circulating viruses to determine viral genotype and phenotype by using in vitro and in vivo infection models.

Isolation, Sequence, Infectivity, and Replication Kinetics of Severe Acute Respiratory Syndrome Coronavirus 2

A recent study by Tang et al. (2020) claimed that two major types of SARS-CoV-2 had evolved in the ongoing COVID-19 pandemic and that one of these types was more “aggressive” than the other. Given the repercussions of these claims and the intense media coverage of these types of articles, we have examined in detail the data presented by Tang et al, and show that the major conclusions of that paper cannot be substantiated. Using examples from other viral outbreaks we discuss the difficulty in demonstrating the existence or nature of a functional effect of a viral mutation, and we advise against overinterpretation of genomic data during the pandemic.

No evidence for distinct types in the evolution of SARS-CoV-2

The World Health Organization characterized the COVID-19 as a pandemic in March 2020, the second pandemic of the 21st century. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a positive-stranded RNA betacoronavirus of the family Coronaviridae. Expanding virus populations, as that of SARS-CoV-2, accumulate a number of narrowly shared polymorphisms imposing a confounding effect on traditional clustering methods. In this context, approaches that reduce the complexity of the sequence space occupied by the SARS-CoV-2 population are necessary for a robust clustering. Here, we proposed the subdivision of the global SARS-CoV-2 population into sixteen well-defined subtypes by focusing on the widely shared polymorphisms in nonstructural (nsp3, nsp4, nsp6, nsp12, nsp13 and nsp14) cistrons, structural (spike and nucleocapsid) and accessory (ORF8) genes. Six virus subtypes were predominant in the population, but all sixteen showed amino acid replacements which might have phenotypic implications. We hypothesize that the virus subtypes detected in this study are records of the early stages of the SARS-CoV-2 diversification that were randomly sampled to compose the virus populations around the world, a typical founder effect. The genetic structure determined for the SARS-CoV-2 population provides substantial guidelines for maximizing the effectiveness of trials for testing the candidate vaccines or drugs.

The global population of SARS-CoV-2 is composed of six major subtypes

We examined 169 genomes of SARS-CoV-2 and found that they can be classified into two major genotypes, Type I and Type II. Type I can be further divided into Type IA and IB. Our phylogenetic analysis showed that the Type IA resembles the ancestral SARS-CoV-2 most. Type II was likely evolved from Type I and predominant in the infections. Our results suggest that Type II SARS-CoV-2 was the source of the outbreak in the Wuhan Huanan market and it was likely originated from a super-spreader. The outbreak caused by the Type I virus should have occurred somewhere else, because the patients had no direct link to the market. Furthermore, by analyzing three genomic sites that distinguish Type I and Type II strains, we found that synonymous changes at two of the three sites confer higher protein translational efficiencies in Type II strains than in Type I strains, which might explain why Type II strains are predominant, implying that Type II is more contagious (transmissible) than Type I. These findings could be valuable for the current epidemic prevention and control.

Genomic variations of SARS-CoV-2 suggest multiple outbreak sources of transmission

Abstract There is a current worldwide outbreak of the novel coronavirus Covid-19 (coronavirus disease 2019; the pathogen called SARS-CoV-2; previously 2019-nCoV), which originated from Wuhan in China and has now spread to 6 continents including 66 countries, as of 24:00 on March 2, 2020. Governments are under increased pressure to stop the outbreak from spiraling into a global health emergency. At this stage, preparedness, transparency, and sharing of information are crucial to risk assessments and beginning outbreak control activities. This information should include reports from outbreak site and from laboratories supporting the investigation. This paper aggregates and consolidates the epidemiology, clinical manifestations, diagnosis, treatments and preventions of this new type of coronavirus.

The SARS-CoV-2 outbreak: What we know

COVID-19 pandemic is a major human tragedy. Worldwide, SARS-CoV-2 has already infected over 3 million and has killed about 230,000 people. SARS-CoV-2 originated in China and, within three months, has evolved to an additional 10 subtypes. One particular subtype with a non-silent (Aspartate to Glycine) mutation at 614th position of the Spike protein (D614G) rapidly outcompeted other pre-existing subtypes, including the ancestral. We assessed that D614G mutation generates an additional serine protease (Elastase) cleavage site near the S1-S2 junction of the Spike protein. We also identified that a single nucleotide deletion (delC) at a known variant site (rs35074065) in a cis-eQTL of TMPRSS2, is extremely rare in East Asians but is common in Europeans and North Americans. The delC allele facilitates entry of the 614G subtype into host cells, thus accelerating the spread of 614G subtype in Europe and North America where the delC allele is common. The delC allele at the cis-eQTL locus rs35074065 of TMPRSS2 leads to overexpression of both TMPRSS2 and a nearby gene MX1. The cis-eQTL site, rs35074065 overlaps with a transcription factor binding site of an activator (IRF1) and a repressor (IRF2). IRF1 activator can bind to variant delC allele, but IRF2 repressor fails to bind. Thus, in an individual carrying the delC allele, there is only activation, but no repression. On viral entry, IRF1 mediated upregulation of MX1 leads to neutrophil infiltration and processing of 614G mutated Spike protein by neutrophil Elastase. The simultaneous processing of 614G spike protein by TMPRSS2 and Elastase serine proteases facilitates the entry of the 614G subtype into host cells. Thus, SARS-CoV-2, particularly the 614G subtype, has spread more easily and with higher frequency to Europe and North America where the delC allele regulating expression of TMPRSS2 and MX1 host proteins is common, but not to East Asia where this allele is rare.

Global Spread of SARS-CoV-2 Subtype with Spike Protein Mutation D614G is Shaped by Human Genomic Variations that Regulate Expression of TMPRSS2 and MX1 Genes

Coronaviruses have recently caused world-wide severe outbreaks: SARS (Severe Acute Respiratory Syndrome) in 2002 and MERS (Middle-East Respiratory Syndrome) in 2012. At the end of 2019, a new coronavirus outbreak appeared in Wuhan (China) seafood market as first focus of infection, becoming a pandemics in 2020, spreading mainly into Europe and Asia. Although the virus family is well-known, this specific virus presents considerable differences, as higher transmission rates, being a challenge for diagnostic methods, treatments and vaccines. Coronavirus.pro is a C++ application which simulates Coronavirus replication cycle. This software has identified virus type in short times and provided FASTA files of virus proteins, a list of mRNA sequences and secondary structures. Furthermore, the software has identified a list of structural, non-structural and accessory proteins in 2019-nCoV virus genome more similar to SARS than to MERS, as several fusion proteins characteristics of this virus type. These results are useful as a first step in order to develop diagnostic methods, new vaccines or antiviral drugs, which could avoid virus replication in any stage: fusion inhibitors, RdRp inhibitors and PL2pro/3CLpro protease inhibitors.

Coronavirus SARS-CoV-2: Analysis of subgenomic mRNA transcription, 3CLpro and PL2pro protease cleavage sites and protein synthesis

There is a current worldwide outbreak of the novel coronavirus Covid-19 (coronavirus disease 2019; the pathogen called SARS-CoV-2; previously 2019-nCoV), which originated from Wuhan in China and has now spread to 6 continents including 66 countries, as of 24:00 on March 2, 2020. Governments are under increased pressure to stop the outbreak from spiraling into a global health emergency. At this stage, preparedness, transparency, and sharing of information are crucial to risk assessments and beginning outbreak control activities. This information should include reports from outbreak site and from laboratories supporting the investigation. This paper aggregates and consolidates the epidemiology, clinical manifestations, diagnosis, treatments and preventions of this new type of coronavirus.

The SARS-CoV-2 outbreak: What we know

A recent outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected more than 1100000 (April 5, 2020) individuals worldwide and is spreading rapidly. The virus is reported to be derived from bats and the infection was first reported in China. Similar to the severe acute respiratory syndrome and the Middle East respiratory syndrome coronaviruses, it is responsible for respiratory tract infection. Real time polymerase chain reaction and radiography are the two main diagnostic methods. Guidelines from the Center for Disease Control and Prevention and the World Health Organization (WHO) should be followed for diagnostic and precautionary measures. Treatment of the infection is still not available; however, antivirals are under clinical trials.

SARS-CoV-2; What We Know so far.

Taiwan experienced two waves of imported cases of coronavirus disease 2019 (COVID-19), first from China in January to late February, followed by those from other countries starting in early March. Additionally, several cases could not be traced to any imported cases and were suspected as sporadic local transmission. Twelve full viral genomes were determined in this study by Illumina sequencing either from virus isolates or directly from specimens, among which 5 originated from clustered infections. Phylogenetic tree analysis revealed that these sequences were in different clades, indicating that no major strain has been circulating in Taiwan. A deletion in open reading frame 8 was found in one isolate. Only a 4-nucleotide difference was observed among the 5 genomes from clustered infections.

Sequence variation among SARS-CoV-2 isolates in Taiwan

Coronaviruses (CoVs) are one of the largest groups of positive-sense RNA virus families within the Nidovirales order, which are further classified into four genera: alpha, beta, gamma, and delta. Coronaviruses have an extensive range of natural hosts and are known to be responsible for a broad spectrum of diseases in multiple species. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing coronavirus disease 2019 (COVID-19) that has unleashed a global threat to public health and the economy. Coronaviruses are extensively present in birds and mammals, with horseshoe bats (Rhinolophus affinis), being the reservoir for the ongoing SARS-CoV-2 that seems to have resulted from a zoonotic spillover to the human host, causing respiratory infections, lung injury and Acute Respiratory Distress Syndrome(ARDS). About six coronavirus serotypes are linked with the disease in humans, namely HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1, SARS-CoV, SARS-CoV-2, and MERS-CoV. SARS-CoV-2 is the seventh CoV to infect humans. We analyzed the genome sequence of CoV-2 from isolates derived from China as well from India and encountered minute variations in their sequence. A cladogram analysis revealed the predominant strain circulating in India belongs to the A2a clad. We took one such strain (MT012098) and performed a rigorous in-silico genotypic and antigenic analysis to identify its relatedness to other strains. Further, we also performed a detailed prediction for B and T cell epitopes using BepiPred 2.0 server and NetCTL 1.2 server (DTU Bioinformatics), respectively. We hope this information may assist in an effective vaccine designing program against SARS-CoV-2.

Genotypic and antigenic study of SARS-CoV-2 from an Indian isolate

Abstract On December 31, 2019, an outbreak of pneumonia of unknown etiology was detected in the city of Wuhan (China). A week later, a new coronavirus was isolated in these patients, initially designated as 2019-nCoV and subsequently SARS-CoV-2. This is a new virus that is much closer genetically to the coronavirus of bats than to human SARS. The new virus infects and replicates in the lung parenchyma pneumocytes and macrophages in which the ACE-2 cell receptor resides. He has now infected many more people than his predecessors (>85,000). From the clinical point of view, those infected have an average age of 55 years; the main symptoms are fever, dry cough, lymphopenia, dyspnea, and pneumonia in its severe form. The overall lethality rate is 2-3% in China and 0.1% in cases detected outside of this country. The incubation period has been set at about 3 days (0-24 days). There are no specific antivirals or vaccines.

The SARS-CoV-2, a new pandemic zoonosis that threatens the world

In January 2020, we identified two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients in a familial cluster with one person coming from Wuhan, China. The complete genome sequences of two SARS-CoV-2 strains isolated from these patients were identical and 99.98% similar to strains isolated in Wuhan. This is genetically suggestive of human-to-human transmission of SARS-CoV-2 and indicates Wuhan as the most plausible origin of the early outbreak in Vietnam. The younger patient had a mild upper respiratory illness and a brief viral shedding, whereas the elderly with multi-morbidity had pneumonia, prolonged viral shedding, and residual lung damage. The evidence of nonsynonymous substitutions in the ORF1ab region of the viral sequence warrants further studies.

Clinical features, isolation, and complete genome sequence of severe acute respiratory syndrome coronavirus 2 from the first two patients in Vietnam

Four signature groups of single-nucleotide variants (SNVs) were identified using two-way clustering method in about twenty thousand high quality and high coverage SARS-CoV-2 complete genome sequences. Some frequently occurred SNVs predominate but are mutually exclusively presented in patients from different countries and areas. These major SNV signatures exhibited distinguished evolution patterns overtime. Although it was rare, our data indicated possible cross-infections with multiple groups of SNVs existed simultaneously in some patients, suggesting infections from different SARS-CoV-2 clades or potential re-combination of SARS-CoV-2 sequences. Interestingly nucleotide substitutions among SARS-CoV-2 genomes tend to occur at the sites where one bat RaTG13 coronavirus sequences differ from Wuhan-Hu-1 genome, indicating the tolerance of mutations on those sites or suggesting that major viral strains might exist between Wuhan-Hu-1 and RaTG13 coronavirus.

Distinct genetic spectrums and evolution patterns of SARS-CoV-2

Isolation, Sequence, Infectivity, and Replication Kinetics of Severe Acute Respiratory Syndrome Coronavirus 2.

Taiwan experienced two waves of imported infections with Coronavirus Disease 2019 (COVID-19). This study aimed at investigating the genomic variation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Taiwan and compared their evolutionary trajectories with the global strains. We performed culture and full-genome sequencing of SARS-CoV-2 strains followed by phylogenetic analysis. A 382-nucleotides deletion in open reading frame 8 (ORF8) was found in a Taiwanese strain isolated from a patient on February 4, 2020 who had a travel history to Wuhan. Patients in the first wave also included several sporadic, local transmission cases. Genomes of 5 strains sequenced from clustered infections were classified into a new clade with ORF1ab-V378I mutation, in addition to 3 dominant clades ORF8-L84S, ORF3a-G251V and S-D614G. This highlighted clade also included some strains isolated from patients who had a travel history to Turkey and Iran. The second wave mostly resulted from patients who had a travel history to Europe and Americas. All Taiwanese viruses were classified into various clades. Genomic surveillance of SARS-CoV-2 in Taiwan revealed a new ORF8-deletion mutant and a virus clade that may be associated with infections in the Middle East, which contributed to a better understanding of the global SARS-CoV-2 transmission dynamics.

SARS-CoV-2 genomic surveillance in Taiwan revealed novel ORF8-deletion mutant and clade possibly associated with infections in Middle East

SARS-CoV-2 genomic surveillance in Taiwan revealed novel ORF8-deletion mutant and clade possibly associated with infections in Middle East.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) emerged in China in late December 2019 and has spread worldwide. Coronaviruses are enveloped, positive sense, single-stranded RNA viruses and employ a complicated pattern of virus genome length RNA replication as well as transcription of genome length and leader containing subgenomic RNAs. Although not fully understood, both replication and transcription are thought to take place in so-called double-membrane vesicles in the cytoplasm of infected cells. We here describe detection of SARS-CoV-2 subgenomic RNAs in diagnostic samples up to 17 days after initial detection of infection, and provide a likely explanation not only for extended PCR positivity of such samples, but also for discrepancies in results of different PCR methods described by others. Overall, we present evidence that subgenomic RNAs may not be an indicator of active coronavirus replication/infection, but that these RNAs, similar to the virus genome RNA, may be rather stable, and thus detectable for an extended period, most likely due to their close association with cellular membranes.

SARS-CoV-2 genomic and subgenomic RNAs in diagnostic samples are not an indicator of active replication

The SARS-CoV-2 epidemic started in late December 2019 in Wuhan, China, and has since impacted a large portion of China and raised major global concern. Herein, we investigated the extent of molecular divergence between SARS-CoV-2 and other related coronaviruses. Although we found only 4% variability in genomic nucleotides between SARS-CoV-2 and a bat SARS-related coronavirus (SARSr-CoV; RaTG13), the difference at neutral sites was 17%, suggesting the divergence between the two viruses is much larger than previously estimated. Our results suggest that the development of new variations in functional sites in the receptor-binding domain (RBD) of the spike seen in SARS-CoV-2 and viruses from pangolin SARSr-CoVs are likely caused by mutations and natural selection besides recombination. Population genetic analyses of 103 SARS-CoV-2 genomes indicated that these viruses evolved into two major types (designated L and S), that are well defined by two different SNPs that show nearly complete linkage across the viral strains sequenced to date. Although the L type (∼70%) is more prevalent than the S type (∼30%), the S type was found to be the ancestral version. Whereas the L type was more prevalent in the early stages of the outbreak in Wuhan, the frequency of the L type decreased after early January 2020. Human intervention may have placed more severe selective pressure on the L type, which might be more aggressive and spread more quickly. On the other hand, the S type, which is evolutionarily older and less aggressive, might have increased in relative frequency due to relatively weaker selective pressure. These findings strongly support an urgent need for further immediate, comprehensive studies that combine genomic data, epidemiological data, and chart records of the clinical symptoms of patients with coronavirus disease 2019 (COVID-19).

On the origin and continuing evolution of SARS-CoV-2

The outbreak of COVID-19 started in mid-December 2019 in Wuhan, China. Up to 29 February 2020, SARS-CoV-2 (HCoV-19 / 2019-nCoV) had infected more than 85 000 people in the world. In this study, we used 93 complete genomes of SARS-CoV-2 from the GISAID EpiFlu(TM) database to investigate the evolution and human-to-human transmissions of SARS-CoV-2 in the first two months of the outbreak. We constructed haplotypes of the SARS-CoV-2 genomes, performed phylogenomic analyses and estimated the potential population size changes of the virus. The date of population expansion was calculated based on the expansion parameter tau (τ) using the formula t=τ/2u. A total of 120 substitution sites with 119 codons, including 79 non-synonymous and 40 synonymous substitutions, were found in eight coding-regions in the SARS-CoV-2 genomes. Forty non-synonymous substitutions are potentially associated with virus adaptation. No combinations were detected. The 58 haplotypes (31 found in samples from China and 31 from outside China) were identified in 93 viral genomes under study and could be classified into five groups. By applying the reported bat coronavirus genome (bat-RaTG13-CoV) as the outgroup, we found that haplotypes H13 and H38 might be considered as ancestral haplotypes, and later H1 was derived from the intermediate haplotype H3. The population size of the SARS-CoV-2 was estimated to have undergone a recent expansion on 06 January 2020, and an early expansion on 08 December 2019. Furthermore, phyloepidemiologic approaches have recovered specific directions of human-to-human transmissions and the potential sources for international infected cases.

Decoding the evolution and transmissions of the novel pneumonia coronavirus (SARS-CoV-2 / HCoV-19) using whole genomic data

A novel pathogen, named SARS-CoV-2, has caused an unprecedented worldwide pandemic in the first half of 2020. As the SARS-CoV-2 genome sequences have become available, one of the important focus of scientists has become tracking variations in the viral genome. In this study, 30366 SARS-CoV-2 isolate genomes were aligned using the software developed by our group (ODOTool) and 11 variations in SARS-CoV-2 genome over 10% of whole isolates were discussed. Results indicated that, frequency rates of these 11 variations change between 3.56%–88.44 % and these rates differ greatly depending on the continents they have been reported. Despite some variations being in low frequency rate in some continents, C14408T and A23403G variations on Nsp12 and S protein, respectively, observed to be the most prominent variations all over the world, in general, and both cause missense mutations. It is also notable that most of isolates carry C14408T and A23403 variations simultaneously and also nearly all isolates carrying the G25563T variation on ORF3a, also carry C14408T and A23403 variations, although their location distributions are not similar. All these data should be considered towards development of vaccine and antiviral treatment strategies as well as tracing diversity of virus in all over the world.

An updated analysis of variations in SARS-CoV-2 genome

To determine prevalence of, seroprevalence of, and potential exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among a cohort of evacuees returning to the United States from Wuhan, China, in January 2020, we conducted a cross-sectional study of quarantined evacuees from 1 repatriation flight. Overall, 193 of 195 evacuees completed exposure surveys and submitted upper respiratory or serum specimens or both at arrival in the United States. Nearly all evacuees had taken preventive measures to limit potential exposure while in Wuhan, and none had detectable SARS-CoV-2 in upper respiratory tract specimens, suggesting the absence of asymptomatic respiratory shedding among this group at the time of testing. Evidence of antibodies to SARS-CoV-2 was detected in 1 evacuee, who reported experiencing no symptoms or high-risk exposures in the previous 2 months. These findings demonstrated that this group of evacuees posed a low risk of introducing SARS-CoV-2 to the United States.

Severe Acute Respiratory Syndrome Coronavirus 2 Prevalence, Seroprevalence, and Exposure Among Evacuees from Wuhan, China, 2020.

SARS-CoV-2 emerged in December 2019 in Wuhan, China and has since infected over 1.5 million people, of which over 107,000 have died. As SARS-CoV-2 spreads across the planet, speculations remain about the range of human cells that can be infected by SARS-CoV-2. In this study, we report the isolation of SARS-CoV-2 from two cases of COVID-19 in Toronto, Canada. We determined the genomic sequences of the two isolates and identified single nucleotide changes in representative populations of our virus stocks. More importantly, we tested a wide range of human immune cells for productive infection with SARS-CoV-2. Here we confirm that human primary peripheral blood mononuclear cells (PBMCs) are not permissive for SARS-CoV-2. As SARS-CoV-2 continues to spread globally, it is essential to monitor single nucleotide polymorphisms in the virus and to continue to isolate circulating viruses to determine viral genotype and phenotype using in vitro and in vivo infection models.

Isolation, sequence, infectivity and replication kinetics of SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus 2 Prevalence, Seroprevalence, and Exposure Among Evacuees from Wuhan, China, 2020

Since December 2019, the emergence of the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) infection has been reported unexpectedly in Wuhan, China, with staggering infection speed across China and around the world. To date, seven known strains of HCoVs belonging to four genera (i.e., α?, β?, γ, and δ-CoV) have been recognized; the latest one has been identified as the SARS-CoV-2. Although the common transmission routes of SARS-CoV-2 is the respiratory tract, it seems that other routes such as the gastrointestinal tract may be effective for the entry of the virus in the body. Although there are no biological markers to predict the susceptibility of humans to COVID-19, several risk factors have been identified to predict the susceptibility of patients to COVID-19. Initial data revealed that males, pregnant women, elderly, and underlying conditions predispose patients to higher morbidity or mortality and also might be at risk for a severe infection of COVID-19. There is a greater need to better understand the mechanisms and risk factors of transmission routes. To date, despite the whole world effort to review various aspects of SARS-CoV-2, including epidemiology, clinical manifestations, diagnosis, and treatment options, there are still gaps in the knowledge of this disease and many issues remain unclear. Therefore, there is an urgent need for update data on SARS-CoV-2. Here, this study provide the current epidemiological status (transmission routes and risk of transmission, possible origins and source, mortality and morbidity risk, and geographical distribution) of the SARS-CoV-2 in the world in 2020.

Emerging coronaviruses: first SARS, second MERS and third SARS-CoV-2: epidemiological updates of COVID-19.

Clinical laboratory testing routinely provides actionable results, which help direct patient care in the inpatient and outpatient settings. Since December 2019, a novel coronavirus (SARS-CoV-2) has been causing disease (COVID-19 [coronavirus disease 2019]) in patients, beginning in China and now extending worldwide. In this context of a novel viral pandemic, clinical laboratories have developed multiple novel assays for SARS-CoV-2 diagnosis and for managing patients afflicted with this illness. These include molecular and serologic-based tests, some with point-of-care testing capabilities. Herein, we present an overview of the types of testing available for managing patients with COVID-19, as well as for screening of potential plasma donors who have recovered from COVID-19.

Types of Assays for SARS-CoV-2 Testing: A Review.

Coronavirus disease 2019 (COVID-19) is newly emerging human infectious diseases, which is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, also previously known as 2019-nCoV). Within two months of the outbreak, more than 80,000 cases of COVID-19 have been confirmed worldwide. Since the human to human transmission occurred easily and the human infection is rapidly increasing, the sensitive and early diagnosis is essential to prevent the global outbreak. Recently, World Health Organization (WHO) announced various primer and probe sets for SARS-CoV-2 previously developed in China, Germany, Hong Kong, Japan, Thailand, and USA. In this study, we compared the ability to detect SARS-CoV-2 RNA among the seven primer-probe sets for N gene and the three primer-probe sets for Orf1 gene. The result of the comparative analysis represented that the ‘2019-nCoV_N2, N3’ of USA and the ‘ORF1ab’ of China are the most sensitive primer-probe sets for N and Orf1 genes, respectively. Therefore, the appropriate combination from ORF1ab (China), 2019-nCoV_N2, N3 (USA), and NIID_2019-nCOV_N (Japan) sets should be selected for the sensitive and reliable laboratory confirmation of SARS-CoV-2.

Comparative analysis of primer-probe sets for the laboratory confirmation of SARS-CoV-2

Tremendous effort has been given to the development of diagnostic tests, preventive vaccines, and therapeutic medicines for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Much of this development has been based on the reference genome collected on January 5, 2020. Based on the genotyping of 6156 genome samples collected up to April 24, 2020, we report that SARS-CoV-2 has had 4459 alarmingly mutations which can be clustered into five subtypes. We introduce mutation ratio and mutation $h$-index to characterize the protein conservativeness and unveil that SARS-CoV-2 envelope protein, main protease, and endoribonuclease protein are relatively conservative, while SARS-CoV-2 nucleocapsid protein, spike protein, and papain-like protease are relatively non-conservative. In particular, the nucleocapsid protein has more than half its genes changed in the past few months, signaling devastating impacts on the ongoing development of COVID-19 diagnosis, vaccines, and drugs.

Decoding SARS-CoV-2 transmission, evolution and ramification on COVID-19 diagnosis, vaccine, and medicine

The outbreak of COVID-19 started in mid-December 2019 in Wuhan, China. Up to 29 February 2020, SARS-CoV-2 (HCoV-19 / 2019-nCoV) had infected more than 85 000 people in the world. In this study, we used 93 complete genomes of SARS-CoV-2 from the GISAID EpiFlu TM database to investigate the evolution and human-to-human transmissions of SARS-CoV-2 in the first two months of the outbreak. We constructed haplotypes of the SARS-CoV-2 genomes, performed phylogenomic analyses and estimated the potential population size changes of the virus. The date of population expansion was calculated based on the expansion parameter tau ( τ) using the formula t= τ/2 u. A total of 120 substitution sites with 119 codons, including 79 non-synonymous and 40 synonymous substitutions, were found in eight coding-regions in the SARS-CoV-2 genomes. Forty non-synonymous substitutions are potentially associated with virus adaptation. No combinations were detected. The 58 haplotypes (31 found in samples from China and 31 from outside China) were identified in 93 viral genomes under study and could be classified into five groups. By applying the reported bat coronavirus genome (bat-RaTG13-CoV) as the outgroup, we found that haplotypes H13 and H38 might be considered as ancestral haplotypes, and later H1 was derived from the intermediate haplotype H3. The population size of the SARS-CoV-2 was estimated to have undergone a recent expansion on 06 January 2020, and an early expansion on 08 December 2019. Furthermore, phyloepidemiologic approaches have recovered specific directions of human-to-human transmissions and the potential sources for international infected cases.

An ongoing outbreak of pneumonia caused by a novel coronavirus, currently designated as the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was reported recently. However, as SARS-CoV-2 is an emerging virus, we know little about it. In this review, we summarize the key events occurred during the early stage of SARS-CoV-2 outbreak, the basic characteristics of the pathogen, the signs and symptoms of the infected patients as well as the possible transmission pathways of the virus. Furthermore, we also review the current knowledge on the origin and evolution of the SARS-CoV-2. We highlight bats as the potential natural reservoir and pangolins as the possible intermediate host of the virus, but their roles are waiting for further investigation. Finally, the advances in the development of chemotherapeutic options are also briefly summarized.

SARS-CoV-2: an Emerging Coronavirus that Causes a Global Threat

To investigate the evolutionary history of the current pandemic outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a total of 137 genomes of coronavirus strains with release dates between January 2019 and 25 March 2020, were analyzed. To investigate the potential intermediate host of the SARS-CoV-2, we analyzed spike glycoprotein sequences from different animals, with particular emphasis on bats. We performed phylogenetic analysis and structural reconstruction of the spike glycoproteins with subsequent alignment and comparison. Our phylogenetic results revealed that SARS-CoV-2 was more similar to the bats' betacoronavirus isolates: HKU5-related from Pipistrellus abramus and HKU4-related from Tylonycteris pachypus. We also identified a yak betacoronavirus strain, YAK/HY24/CH/2017, as the closest match in the comparison of the structural models of spike glycoproteins. Interestingly, a set of unique features has been described for this particular strain of the yak betacoronavirus. Therefore, our results suggest that the human SARS-CoV-2, responsible for the current outbreak of COVID-19, could also come from yak as an intermediate host.

SARS-CoV-2: Structural diversity, phylogeny, and potential animal host identification of spike glycoprotein

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused thousands of deaths worldwide, including >18,000 in New York City (NYC) alone. The sudden emergence of this pandemic has highlighted a pressing clinical need for rapid, scalable diagnostics that can detect infection, interrogate strain evolution, and identify novel patient biomarkers. To address these challenges, we designed a fast (30-minute) colorimetric test (LAMP) for SARS-CoV-2 infection from naso/oropharyngeal swabs, plus a large-scale shotgun metatranscriptomics platform (total-RNA-seq) for host, bacterial, and viral profiling. We applied both technologies across 857 SARS-CoV-2 clinical specimens and 86 NYC subway samples, providing a broad molecular portrait of the COVID-19 NYC outbreak. Our results define new features of SARS-CoV-2 evolution, nominate a novel, NYC-enriched viral subclade, reveal specific host responses in interferon, ACE, hematological, and olfaction pathways, and examine risks associated with use of ACE inhibitors and angiotensin receptor blockers. Together, these findings have immediate applications to SARS-CoV-2 diagnostics, public health, and new therapeutic targets.

Shotgun Transcriptome and Isothermal Profiling of SARS-CoV-2 Infection Reveals Unique Host Responses, Viral Diversification, and Drug Interactions

On December 31, 2019, an outbreak of pneumonia of unknown etiology was detected in the city of Wuhan (China). A week later, a new coronavirus was isolated in these patients, initially designated as 2019-nCoV and subsequently SARS-CoV-2. This is a new virus that is much closer genetically to the coronavirus of bats than to human SARS. The new virus infects and replicates in the lung parenchyma pneumocytes and macrophages in which the ACE-2 cell receptor resides. He has now infected many more people than his predecessors (> 85,000). From the clinical point of view, those infected have an average age of 55 years; the main symptoms are fever, dry cough, lymphopenia, dyspnea, and pneumonia in its severe form. The overall lethality rate is 2-3% in China and 0.1% in cases detected outside of this country. The incubation period has been set at about 3 days (0-24 days). There are no specific antivirals or vaccines.

El SARS-CoV-2, una nueva zoonosis pandémica que amenaza al mundo

Types of Assays for SARS-CoV-2 Testing: A Review

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the virus strain that causes coronavirus disease 2019 (COVID-19), was first identified in Wuhan, China in December 2019. It spread to several countries across continents and infected more than one million people within three months. While there is no consensus on the treatment of the disease yet, understanding the virus and its transmission is a cardinal priority. SARS-CoV-2 can be transmitted through bodily fluid. Upon inoculation, the surface enzyme angiotensin-converting enzyme 2 (ACE2) acts as a receptor protein for viral entry. The mean incubation period is 5.1 days, and infected individuals can exhibit a variety of symptoms from fever, cough, dyspnea, and respiratory failure to even multiorgan failure. Given the current situation, it is of paramount importance to understand the virus as thoroughly as possible. In this review, we discuss the background, epidemiology, possible pathophysiology, clinical presentation, and diagnostic studies related to SARS-CoV-2 infection. We also elaborate on the current research and evidence on treatment options and vaccine development based on the literature.

A Comprehensive Review of Severe Acute Respiratory Syndrome Coronavirus 2

Although primary genomic analysis has revealed that severe acute respiratory syndrome coronavirus (SARS CoV) is a new type of coronavirus, the different protein trees published in previous reports have provided no conclusive evidence indicating the phylogenetic position of SARS CoV. To clarify the phylogenetic relationship between SARS CoV and other coronaviruses, we compiled a large data set composed of 7 concatenated protein sequences and performed comprehensive analyses, using the maximum-likelihood, Bayesian-inference, and maximum-parsimony methods. All resulting phylogenetic trees displayed an identical topology and supported the hypothesis that the relationship between SARS CoV and group 2 CoVs is monophyletic. Relationships among all major groups were well resolved and were supported by all statistical analyses.

Monophyletic Relationship between Severe Acute Respiratory Syndrome Coronavirus and Group 2 Coronaviruses

Starting around December 2019, an epidemic of pneumonia, which was named COVID-19 by the World Health Organization, broke out in Wuhan, China, and is spreading throughout the world. A new coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by the Coronavirus Study Group of the International Committee on Taxonomy of Viruses was soon found to be the cause. At present, the sensitivity of clinical nucleic acid detection is limited, and it is still unclear whether it is related to genetic variation. In this study, we retrieved 95 full-length genomic sequences of SARAS-CoV-2 strains from the National Center for Biotechnology Information and GISAID databases, established the reference sequence by conducting multiple sequence alignment and phylogenetic analyses, and analyzed sequence variations along the SARS-CoV-2 genome. The homology among all viral strains was generally high, among them, 99.99% (99.91%-100%) at the nucleotide level and 99.99% (99.79%-100%) at the amino acid level. Although overall variation in open-reading frame (ORF) regions is low, 13 variation sites in 1a, 1b, S, 3a, M, 8, and N regions were identified, among which positions nt28144 in ORF 8 and nt8782 in ORF 1a showed mutation rate of 30.53% (29/95) and 29.47% (28/95), respectively. These findings suggested that there may be selective mutations in SARS-COV-2, and it is necessary to avoid certain regions when designing primers and probes. Establishment of the reference sequence for SARS-CoV-2 could benefit not only biological study of this virus but also diagnosis, clinical monitoring and intervention of SARS-CoV-2 infection in the future.

The establishment of reference sequence for SARS-CoV-2 and variation analysis

The SARS-CoV2 causes a disease spectrum that includes asymptomatic and mildly symptomatic infections with subclinical manifestations but which can nevertheless still be potentially contagious. Evidence from SARS-CoV2 infected macaque monkeys and from studies with seasonal coronaviruses suggests that the infection is likely to produce an immunity that is protective for a certain period of time. Available test methods enable a high degree of reliability, e.g. if high-quality serological methods are combined. Although individual test results have to be interpreted with caution, serosurveillance in a tertiary eye care center and large eye research institute can reduce anxiety and provide clarity regarding the actual number of (unreported) SARS-CoV2 infections.

Seroprävalenz und SARS-CoV-2-Testung in Gesundheitsberufen./ [Seroprevalence and SARS-CoV-2 testing in healthcare occupations]

[This corrects the article DOI: 10.1016/j.cmrp.2020.04.001.].

Corrigendum to 'An Overview of Coronaviruses including the SARS-2 Coronavirus - Molecular Biology, Epidemiology and Clinical Implications' [Cur Med Res Pract. (2019) Vol. 10, pages 54-64]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infectivity is a major concern in coronavirus disease 2019 (COVID-19) prevention and economic reopening. However, rigorous determination of SARS-COV-2 infectivity is essentially impossible owing to its continuous evolution with over 13752 single nucleotide polymorphisms (SNP) variants in six different subtypes. We develop an advanced machine learning algorithm based on the algebraic topology to quantitatively evaluate the binding affinity changes of SARS-CoV-2 spike glycoprotein (S protein) and host angiotensin-converting enzyme 2 (ACE2) receptor following the mutations. Based on mutation-induced binding affinity changes, we reveal that five out of six SARS-CoV-2 subtypes have become either moderately or slightly more infectious, while one subtype has weakened its infectivity. We find that SARS-CoV-2 is slightly more infectious than SARS-CoV according to computed S protein-ACE2 binding affinity changes. Based on a systematic evaluation of all possible 3686 future mutations on the S protein receptor-binding domain (RBD), we show that most likely future mutations will make SARS-CoV-2 more infectious. Combining sequence alignment, probability analysis, and binding affinity calculation, we predict that a few residues on the receptor-binding motif (RBM), i.e., 452, 489, 500, 501, and 505, have very high chances to mutate into significantly more infectious COVID-19 strains.

Mutations strengthened SARS-CoV-2 infectivity

The initial cases of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) occurred in Wuhan, China, in December 2019 and swept the world by 23 June 2020 with 8,993,659 active cases, 469,587 deaths across 216 countries, areas or territories. This strongly implies global transmission occurred before the lockdown of China. However, the initial source's transmission routes of SARS-CoV-2 remain obscure and controversial. Research data suggest bat (RaTG13) and pangolin carried CoV were the proximal source of SARS-CoV-2. In this study, we used systematic phylogenetic analysis of Coronavirinae subfamily along with wild type human SARS-CoV, MERS-CoV, and SARS-CoV-2 strains. The key residues of the receptor-binding domain (RBD) and O-linked glycan were compared. SARS-CoV-2 strains were clustered with RaTG13 (97.41% identity), Pangolin-CoV (92.22% identity) and Bat-SL-CoV (80.36% identity), forms a new clade-2 in lineage B of beta-CoV. The alignments of RBD contact residues to ACE2 justified? Those SARS-CoV-2 strains sequences were 100% identical by each other, significantly varied in RaTG13 and pangolin-CoV. SARS-CoV-2 has a polybasic cleavage site with an inserted sequence of PRRA compared to RaTG13 and only PRR to pangolin. Only serine (Ser) in pangolin and both threonine (Thr) and serine (Ser) O-linked glycans were seen in RaTG13, suggesting that a detailed study needed in Pangolin (Manis javanica) and bat (Rhinolophus affinis) related CoV. This article is protected by copyright. All rights reserved.

An update on origin of SARS-CoV-2: Despite closest identity, bat (RaTG13) and Pangolin derived Coronaviruses varied in the critical binding site and O-linked glycan residues

Background & objectives SARS-CoV-2 (Severe acute respiratory syndrome coronavirus-2) is evolving with the progression of the pandemic. This study was aimed to investigate the diversity and evolution of the coronavirus SARS-CoV-2 with progression of the pandemic over time and to identify similarities and differences of viral diversity and evolution across geographical regions (countries). Methods Publicly available data on type definitions based on whole-genome sequences of the SARS-CoV-2 sampled during December and March 2020 from 3636 infected patients spread over 55 countries were collected. Phylodynamic analyses were performed and the temporal and spatial evolution of the virus was examined. Results It was found that (i) temporal variation in frequencies of types of the coronavirus was significant; ancestral viruses of type O were replaced by evolved viruses belonging to type A2a; (ii) spatial variation was not significant; with the spread of SARS-CoV-2, the dominant virus was the A2a type virus in every geographical region; (iii) within a geographical region, there was significant micro-level variation in the frequencies of the different viral types, and (iv) the evolved coronavirus of type A2a swept rapidly across all continents. Interpretation & conclusions SARS-CoV-2 belonging to the A2a type possesses a non-synomymous variant (D614G) that possibly eases the entry of the virus into the lung cells of the host. This may be the reason why the A2a type has an advantage to infect and survive and as a result has rapidly swept all geographical regions. Therefore, large-scale sequencing of coronavirus genomes and, as required, of host genomes should be undertaken in India to identify regional and ethnic variation in viral composition and its interaction with host genomes. Further, careful collection of clinical and immunological data of the host can provide deep learning in relation to infection and transmission of the types of coronavirus genomes.

Analysis of RNA sequences of 3636 SARS-CoV-2 collected from 55 countries reveals selective sweep of one virus type.

In a phylogenetic network analysis of 160 complete human severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) genomes, we find three central variants distinguished by amino acid changes, which we have named A, B, and C, with A being the ancestral type according to the bat outgroup coronavirus. The A and C types are found in significant proportions outside East Asia, that is, in Europeans and Americans. In contrast, the B type is the most common type in East Asia, and its ancestral genome appears not to have spread outside East Asia without first mutating into derived B types, pointing to founder effects or immunological or environmental resistance against this type outside Asia. The network faithfully traces routes of infections for documented coronavirus disease 2019 (COVID-19) cases, indicating that phylogenetic networks can likewise be successfully used to help trace undocumented COVID-19 infection sources, which can then be quarantined to prevent recurrent spread of the disease worldwide.

Phylogenetic network analysis of SARS-CoV-2 genomes

On 31 December, 2019, a cluster of 27 pneumonia cases of unknown etiology was reported by Chinese health authorities in Wuhan City (China) [ ]

Outbreak of Novel Coronavirus (SARS-CoV-2): First Evidences From International Scientific Literature and Pending Questions

Since 2002, beta coronaviruses (CoV) have caused three zoonotic outbreaks, SARS-CoV in 2002-2003, MERS-CoV in 2012, and the newly emerged SARS-CoV-2 in late 2019. However, little is currently known about the biology of SARS-CoV-2. Here, using SARS-CoV-2 S protein pseudovirus system, we confirm that human angiotensin converting enzyme 2 (hACE2) is the receptor for SARS-CoV-2, find that SARS-CoV-2 enters 293/hACE2 cells mainly through endocytosis, that PIKfyve, TPC2, and cathepsin L are critical for entry, and that SARS-CoV-2 S protein is less stable than SARS-CoV S. Polyclonal anti-SARS S1 antibodies T62 inhibit entry of SARS-CoV S but not SARS-CoV-2 S pseudovirions. Further studies using recovered SARS and COVID-19 patients' sera show limited cross-neutralization, suggesting that recovery from one infection might not protect against the other. Our results present potential targets for development of drugs and vaccines for SARS-CoV-2.

Characterization of spike glycoprotein of SARS-CoV-2 on virus entry and its immune cross-reactivity with SARS-CoV

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been declared a global pandemic. Our goal was to determine whether coinfections with other respiratory pathogens occur in a significant subset of SARS-CoV-2 infected patients in the greater New York City metropolitan area. During the period from March 16, 2020 through April 20, 2020, our laboratory detected SARS-CoV-2 infection in 8,990 patients of a total 18,704 tested by real-time reverse-transcription-polymerase-chain-reaction amplification (SARS-CoV-2 Test, cobas® 6800 system, RocheDiagnostics). Amongst the patients who tested positive for SARS-CoV-2, 1,204 were also tested for other respiratory viruses, and concurrent infection was found in only 36 (< 3%). In comparison, coinfection with at least one non-SARS-CoV-2 respiratory viral pathogen was found in 13.1% of patients who tested negative for SARS-CoV-2. Additionally, in patients who tested negative for SARS-CoV-2, the most common respiratory virus co-infections were those commonly seen circulating in the community including rhinovirus/enterovirus, influenza viruses and coronavirus NL63, whereas non-SARS-CoV-2 coronaviridae were the most common concurrent respiratory viruses found in SARS-CoV-2 -positive patients. Additional studies are needed to establish whether simultaneous viral infection in SARS-CoV-2 patients could potential drive viral interference or influence disease outcomes. This article is protected by copyright. All rights reserved.

Co-infection in SARS-CoV-2 infected Patients: Where Are Influenza Virus and Rhinovirus/Enterovirus?

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a new infectious disease that first emerged in Hubei province, China, in December 2019, which was found to be associated with a large seafood and animal market in Wuhan. Airway epithelial cells from infected patients were used to isolate a novel coronavirus, named the SARS-CoV-2, on January 12, 2020, which is the seventh member of the coronavirus family to infect humans. Phylogenetic analysis of full-length genome sequences obtained from infected patients showed that SARS-CoV-2 is similar to severe acute respiratory syndrome coronavirus (SARS-CoV) and uses the same cell entry receptor, angiotensin-converting enzyme 2 (ACE2), as SARS-CoV. The possible person-to-person disease rapidly spread to many provinces in China as well as other countries. Without a therapeutic vaccine or specific antiviral drugs, early detection and isolation become essential against novel Coronavirus. In this review, we introduced current diagnostic methods and criteria for the SARS-CoV-2 in China and discuss the advantages and limitations of the current diagnostic methods, including chest imaging and laboratory detection.

The genetic sequence, origin, and diagnosis of SARS-CoV-2

Summary SARS-CoV-2 is a betacoronavirus responsible for the COVID-19 pandemic. Although the SARS-CoV-2 genome was reported recently, its transcriptomic architecture is unknown. Utilizing two complementary sequencing techniques, we present a high-resolution map of the SARS-CoV-2 transcriptome and epitranscriptome. DNA nanoball sequencing shows that the transcriptome is highly complex owing to numerous discontinuous transcription events. In addition to the canonical genomic and 9 subgenomic RNAs, SARS-CoV-2 produces transcripts encoding unknown ORFs with fusion, deletion, and/or frameshift. Using nanopore direct RNA sequencing, we further find at least 41 RNA modification sites on viral transcripts, with the most frequent motif, AAGAA. Modified RNAs have shorter poly(A) tails than unmodified RNAs, suggesting a link between the modification and the 3′ tail. Functional investigation of the unknown transcripts and RNA modifications discovered in this study will open new directions to our understanding of the life cycle and pathogenicity of SARS-CoV-2.

The Architecture of SARS-CoV-2 Transcriptome

Background & objectives: SARS-CoV-2 (Severe acute respiratory syndrome coronavirus-2) is evolving with the progression of the pandemic. This study was aimed to investigate the diversity and evolution of the coronavirus SARS-CoV-2 with progression of the pandemic over time and to identify similarities and differences of viral diversity and evolution across geographical regions (countries). Methods: Publicly available data on type definitions based on whole-genome sequences of the SARS-CoV-2 sampled during December and March 2020 from 3636 infected patients spread over 55 countries were collected. Phylodynamic analyses were performed and the temporal and spatial evolution of the virus was examined. Results: It was found that (i) temporal variation in frequencies of types of the coronavirus was significant; ancestral viruses of type O were replaced by evolved viruses belonging to type A2a; (ii) spatial variation was not significant; with the spread of SARS-CoV-2, the dominant virus was the A2a type virus in every geographical region; (iii) within a geographical region, there was significant micro-level variation in the frequencies of the different viral types, and (iv) the evolved coronavirus of type A2a swept rapidly across all continents. Interpretation & conclusions: SARS-CoV-2 belonging to the A2a type possesses a non-synomymous variant (D614G) that possibly eases the entry of the virus into the lung cells of the host. This may be the reason why the A2a type has an advantage to infect and survive and as a result has rapidly swept all geographical regions. Therefore, large-scale sequencing of coronavirus genomes and, as required, of host genomes should be undertaken in India to identify regional and ethnic variation in viral composition and its interaction with host genomes. Further, careful collection of clinical and immunological data of the host can provide deep learning in relation to infection and transmission of the types of coronavirus genomes.

Analysis of RNA sequences of 3636 SARS-CoV-2 collected from 55 countries reveals selective sweep of one virus type

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; previously provisionally named 2019 novel coronavirus or 2019-nCoV) disease (COVID-19) in China at the end of 2019 has caused a large global outbreak and is a major public health issue. As of 11 February 2020, data from the World Health Organization (WHO) have shown that more than 43 000 confirmed cases have been identified in 28 countries/regions, with >99% of cases being detected in China. On 30 January 2020, the WHO declared COVID-19 as the sixth public health emergency of international concern. SARS-CoV-2 is closely related to two bat-derived severe acute respiratory syndrome-like coronaviruses, bat-SL-CoVZC45 and bat-SL-CoVZXC21. It is spread by human-to-human transmission via droplets or direct contact, and infection has been estimated to have mean incubation period of 6.4 days and a basic reproduction number of 2.24-3.58. Among patients with pneumonia caused by SARS-CoV-2 (novel coronavirus pneumonia or Wuhan pneumonia), fever was the most common symptom, followed by cough. Bilateral lung involvement with ground-glass opacity was the most common finding from computed tomography images of the chest. The one case of SARS-CoV-2 pneumonia in the USA is responding well to remdesivir, which is now undergoing a clinical trial in China. Currently, controlling infection to prevent the spread of SARS-CoV-2 is the primary intervention being used. However, public health authorities should keep monitoring the situation closely, as the more we can learn about this novel virus and its associated outbreak, the better we can respond.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges

SARS-CoV-2 is a novel strain of coronavirus that has not been previously identified in humans. It has been declared a pandemic and has infected at least 1,844,683 individuals and caused 117,021 deaths as of 14th April 2020. Transmission among humans occurs via close contact with an infected individual that produces respiratory droplets. Patients have been shown to undergo acute respiratory distress syndrome, which is defined as cytokine storm. The diagnosis relies on detection of nucleic acid, IgG/IgM antibodies, and a chest radiograph of the suspected individuals. The genome of SARS-CoV-2 is similar to other coronaviruses that comprise of ten open reading frames (ORFs). SARS-CoV-2 spike protein exhibits higher affinity to ACE2 receptor as compared with SARS-CoV. Repurposing drugs like favipiravir, remdesivir, chloroquine, and TMPRSS2 protease inhibitors have been shown to be effective for the treatment of COVID-19. Personal protective measures should be followed to prevent SARS-CoV-2 infection. In addition, a clinical trial of SARS-CoV-2 vaccine, mRNA-1273, has been started. This chapter provides a glimpse of advancements made in the area of SARS-CoV-2 infection by proving recent clinical and research trials in the field.

Current Insight into the Novel Coronavirus Disease 2019 (COVID-19)

Since 2002, beta coronaviruses (CoV) have caused three zoonotic outbreaks, SARS-CoV in 2002–2003, MERS-CoV in 2012, and the newly emerged SARS-CoV-2 in late 2019. However, little is currently known about the biology of SARS-CoV-2. Here, using SARS-CoV-2 S protein pseudovirus system, we confirm that human angiotensin converting enzyme 2 (hACE2) is the receptor for SARS-CoV-2, find that SARS-CoV-2 enters 293/hACE2 cells mainly through endocytosis, that PIKfyve, TPC2, and cathepsin L are critical for entry, and that SARS-CoV-2 S protein is less stable than SARS-CoV S. Polyclonal anti-SARS S1 antibodies T62 inhibit entry of SARS-CoV S but not SARS-CoV-2 S pseudovirions. Further studies using recovered SARS and COVID-19 patients’ sera show limited cross-neutralization, suggesting that recovery from one infection might not protect against the other. Our results present potential targets for development of drugs and vaccines for SARS-CoV-2.

Tremendous effort has been given to the development of diagnostic tests, preventive vaccines, and therapeutic medicines for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Much of this development has been based on the reference genome collected on January 5, 2020. Based on the genotyping of 15â¯140 genome samples collected up to June 1, 2020, we report that SARS-CoV-2 has undergone 8309 single mutations which can be clustered into six subtypes. We introduce mutation ratio and mutation h-index to characterize the protein conservativeness and unveil that SARS-CoV-2 envelope protein, main protease, and endoribonuclease protein are relatively conservative, while SARS-CoV-2 nucleocapsid protein, spike protein, and papain-like protease are relatively nonconservative. In particular, we have identified mutations on 40% of nucleotides in the nucleocapsid gene in the population level, signaling potential impacts on the ongoing development of COVID-19 diagnosis, vaccines, and antibody and small-molecular drugs.

Decoding SARS-CoV-2 Transmission and Evolution and Ramifications for COVID-19 Diagnosis, Vaccine, and Medicine

In late December 2019, several cases of pneumonia of unknown origin were reported from China, which in early January 2020 were announced to be caused by a novel coronavirus. The virus was later denominated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and defined as the causal agent of coronavirus disease 2019 (COVID-19). Despite massive attempts to contain the disease in China, the virus has spread globally, and COVID-19 was declared a pandemic by the World Health Organization (WHO) in March 2020. Here we provide a short background on coronaviruses, and describe in more detail the novel SARS-CoV-2 and attempts to identify effective therapies against COVID-19.

Coronaviruses and SARS-CoV-2: A Brief Overview

In late December 2019, several cases of pneumonia of unknown origin were reported from China, which in early January 2020 were announced to be caused by a novel coronavirus. The virus was later denominated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and defined as the causal agent of Coronavirus Disease 2019 (COVID-19). Despite massive attempts to contain the disease in China, the virus has spread globally, and COVID-19 was declared a pandemic by the World Health Organization (WHO) in March 2020. Here we provide a short background on coronaviruses, and describe in more detail the novel SARS-CoV-2 and attempts to identify effective therapies against COVID-19.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been confirmed as the etiological pathogen of the coronavirus disease 2019 (COVID-19) SARS-CoV-2 is the seventh member of coronavirus family that can infect humans after the emergence of the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) SARS-CoV-2 is a single-stranded, positive-sense RNA virus Due to its strong infectiousness and the lack of immunity in humans, the epidemic of the COVID-19 is still spreading On January 30, 2020 (local time), the World Health Organization (WHO) defined the epidemics of SARS-CoV-2-infected pneumonia as a Public Health Emergency of International Concern (PHEIC) This paper reviews the etiology and pathogenicity of SARS-CoV-2, and the detection and diagnosis, prevention and control, as well as the treatment of COVID-19

Severe acute respiratory syndrome coronavirus 2 and coronavirus disease 2019

Bats were recently identified as natural reservoirs of SARS-like coronavirus (SL-CoV) or SARS coronavirus-like virus. These viruses, together with SARS coronaviruses (SARS-CoV) isolated from human and palm civet, form a distinctive cluster within the group 2 coronaviruses of the genus Coronavirus, tentatively named group 2b (G2b). In this study, complete genome sequences of two additional group 2b coronaviruses (G2b-CoVs) were determined from horseshoe bat Rhinolophus ferrumequinum (G2b-CoV Rf1) and Rhinolophus macrotis (G2b-CoV Rm1). The bat G2b-CoV isolates have an identical genome organization and share an overall genome sequence identity of 88-92 % among themselves and between them and the human/civet isolates. The most variable regions are located in the genes encoding nsp3, ORF3a, spike protein and ORF8 when bat and human/civet G2b-CoV isolates are compared. Genetic analysis demonstrated that a diverse G2b-CoV population exists in the bat habitat and has evolved from a common ancestor of SARS-CoV.

Full-length genome sequences of two SARS-like coronaviruses in horseshoe bats and genetic variation analysis.

Despite initial findings indicating that SARS-CoV and SARS-CoV-2 are genetically related belonging to the same virus species and that the two viruses used the same entry receptor, angiotensin-converting enzyme 2 (ACE2), our data demonstrated that there is no detectable cross-neutralization by SARS patient sera against SARS-CoV-2. We also found that there are significant levels of neutralizing antibodies in recovered SARS patients 9-17 years after initial infection. These findings will be of significant use in guiding the development of serologic tests, formulating convalescent plasma therapy strategies, and assessing the longevity of protective immunity for SARS-related coronaviruses in general as well as vaccine efficacy.

Lack of cross-neutralization by SARS patient sera towards SARS-CoV-2

SARS-CoV-2 is a betacoronavirus responsible for the COVID-19 pandemic. Although the SARS-CoV-2 genome was reported recently, its transcriptomic architecture is unknown. Utilizing two complementary sequencing techniques, we present a high-resolution map of the SARS-CoV-2 transcriptome and epitranscriptome. DNA nanoball sequencing shows that the transcriptome is highly complex owing to numerous discontinuous transcription events. In addition to the canonical genomic and 9 subgenomic RNAs, SARS-CoV-2 produces transcripts encoding unknown ORFs with fusion, deletion, and/or frameshift. Using nanopore direct RNA sequencing, we further find at least 41 RNA modification sites on viral transcripts, with the most frequent motif, AAGAA. Modified RNAs have shorter poly(A) tails than unmodified RNAs, suggesting a link between the modification and the 3' tail. Functional investigation of the unknown transcripts and RNA modifications discovered in this study will open new directions to our understanding of the life cycle and pathogenicity of SARS-CoV-2.

More than 100,000 people worldwide are known to have been infected with SARS-CoV-2 beginning in December 2019. The virus has now spread to over 93 countries including the United States, with the largest cluster of US cases to date in the Seattle metropolitan area in Washington. Given the rapid increase in the number of local cases, the availability of accurate, high-throughput SARS-CoV-2 testing is vital to efforts to manage the current public health crisis. In the course of optimizing SARS-CoV-2 testing performed by the University of Washington Clinical Virology Lab (UW Virology Lab), we tested assays using seven different primer/probe sets and one assay kit. We found that the most sensitive assays were those the used the E-gene primer/probe set described by Corman et al. (Eurosurveillance 25(3), 2020, https://doi.org/10.2807/1560-7917.ES.2020.25.3.2000045) and the N2 set described by the CDC (Division of Viral Diseases, Centers for Disease Control and Prevention, 2020, https://www.cdc.gov/coronavirus/2019-ncov/downloads/rt-pcr-panel-primer-probes.pdf). All assays tested were found to be highly specific for SARS-CoV-2, with no cross-reactivity with other respiratory viruses observed in our analyses regardless of the primer/probe set or kit used. These results will provide invaluable information to other clinical laboratories who are actively developing SARS-CoV-2 testing protocols at a time when increased testing capacity is urgently needed worldwide.

Comparative Performance of SARS-CoV-2 Detection Assays using Seven Different Primer/Probe Sets and One Assay Kit.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) emerged in late 2019 and since evolved into a global threat with nearly 4.4 million infected people and over 290,000 confirmed deaths worldwide.1 SARS-CoV-2 is an enveloped virus presenting spike (S) glycoproteins on its outer surface. Binding of S to host cell angiotensin converting enzyme 2 (ACE2) is thought to be critical for cellular entry. The host range of the virus extends far beyond humans and non-human primates. Natural and experimental infections have confirmed high susceptibility of cats, ferrets, and hamsters, whereas dogs, mice, rats, pigs, and chickens seem refractory to SARS-CoV-2 infection. To investigate the reason for the variable susceptibility observed in different species, we have developed molecular descriptors to efficiently analyze our dynamic simulation models of complexes between SARS-CoV-2 S and ACE2. Based on our analyses we predict that: (i) the red squirrel is likely susceptible to SARS-CoV-2 infection and (ii) specific mutations in ACE2 of dogs, rats, and mice render them susceptible to SARS-CoV-2 infection.

ACE2-Variants Indicate Potential SARS-CoV-2-Susceptibility in Animals: An Extensive Molecular Dynamics Study

The recent global outbreak of viral pneumonia designated as Coronavirus Disease 2019 (COVID-19) by coronavirus (SARS-CoV-2) has threatened global public health and urged to investigate its source. Whole genome analysis of SARS-CoV-2 revealed ~96% genomic similarity with bat CoV (RaTG13) and clustered together in phylogenetic tree. Furthermore, RaTGl3 also showed 97.43% spike protein similarity with SARS-CoV-2 suggesting that RaTGl3 is the closest strain. However, RBD and key amino acid residues supposed to be crucial for human-to-human and cross-species transmission are homologues between SARS-CoV-2 and pangolin CoVs. These results from our analysis suggest that SARS-CoV-2 is a recombinant virus of bat and pangolin CoVs. Moreover, this study also reports mutations in coding regions of 125 SARS-CoV-2 genomes signifying its aptitude for evolution. In short, our findings propose that homologous recombination has been occurred between bat and pangolin CoVs that triggered cross-species transmission and emergence of SARS-CoV-2, and, during the ongoing outbreak, SARS-CoV-2 is still evolving for its adaptability.

Evidence of the Recombinant Origin and Ongoing Mutations in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

Since early December 2019, a number of pneumonia cases associated with unknown coronavirus infection were identified in Wuhan, China, and many additional cases were identified in other regions of China and in other countries within 3 months. Currently, more than 80,000 cases have been diagnosed in China, including more than 3000 deaths. The epidemic is spreading to the rest of the world, posing a grave challenge to prevention and control. On February 12, 2020, the International Committee on Taxonomy of Viruses and the World Health Organization officially named the novel coronavirus and associated pneumonia as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease 2019 (COVID-19), respectively. According to the recent research on SARS-CoV-2, the virus mainly infects the respiratory system but may cause damage to other systems. In this paper, we will systematically review the pathogenic features, transmission routes, and infection mechanisms of SARS-CoV-2, as well as any adverse effects on the digestive system, urogenital system, central nervous system, and circulatory system, in order to provide a theoretical and clinical basis for the diagnosis, classification, treatment, and prognosis assessment of SARS-CoV-2 infection.

New understanding of the damage of SARS-CoV-2 infection outside the respiratory system

Abstract Since early December 2019, a number of pneumonia cases associated with unknown coronavirus infection were identified in Wuhan, China, and many additional cases were identified in other regions of China and in other countries within 3 months. Currently, more than 80,000 cases have been diagnosed in China, including more than 3,000 deaths. The epidemic is spreading to the rest of the world, posing a grave challenge to prevention and control. On February 12, 2020, the International Committee on Taxonomy of Viruses and the World Health Organization officially named the novel coronavirus and associated pneumonia as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease 2019 (COVID-19), respectively. According to the recent research on SARS-CoV-2, the virus mainly infects the respiratory system but may cause damage to other systems. In this paper, we will systematically review the pathogenic features, transmission routes, and infection mechanisms of SARS-CoV-2, as well as any adverse effects on the digestive system, urogenital system, central nervous system, and circulatory system, in order to provide a theoretical and clinical basis for the diagnosis, classification, treatment, and prognosis assessment of SARS-CoV-2 infection.

Since December 2019, the outbreak of Coronavirus Disease 2019 (COVID-19) spread from Wuhan, China to the world, it has caused more than 87,000 diagnosed cases and more than 3,000 deaths globally. To fight against COVID-19, we carried out research for the near native SARS-CoV-2 and report here our preliminary results obtained. The pathogen of the COVID-19, the native SARS-CoV-2, was isolated, amplified and purified in a BSL-3 laboratory. The whole viral architecture of SARS-CoV-2 was examined by transmission electron microscopy (both negative staining and cryo-EM). We observed that the virion particles are roughly spherical or moderately pleiomorphic. Spikes have nail-like shape towards outside with a long body embedded in the envelope. The morphology of virion observed in our result indicates that the S protein of SARS-CoV-2 is in post-fusion state, with S1 disassociated. This state revealed by cryo-EM first time could provide an important information for the identification and relevant clinical research of this new coronavirus.

Viral Architecture of SARS-CoV-2 with Post-Fusion Spike Revealed by Cryo-EM

In December 2019, a pneumonia outbreak, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and presented a major threat to public health. Nationwide, there were more than 70 000 confirmed cases and 2500 deaths. Most patients were elderly, with severe disease. For acute respiratory infection, reverse-transcription polymerase chain reaction (RT-PCR) is routinely used to detect causative viruses in respiratory secretions. Coronavirus RNA can be detected from nose and throat swabs, sputum and other lower respiratory tract secretions, blood, and feces. Such specimens were examined by RT-PCR. Three targets, RdRP, E, and N genes were detected, indicating samples were positive for SARS-CoV-2. After patient recovery, a chest computed tomography examination, combined with SARS-CoV-2 RNA detection, confirmed diagnosis. However, some recovery patients with negative RNA tests turned RNA positive. The preliminary data is about 14% of discharged patients in Guangdong reported by the Guangdong Center for Disease Control (CDC). This is an important scientific issue. If samples are positive for SARS-CoV-2 RNA, patients should be managed according to infection source. Fortunately, there were no close contacts of second-generation cases. We herein report six SARS-CoV-2 cases confirmed in our hospital, for the changes of results of SARS-CoV-2 RNA should attract attention. Most patients were elderly, with a low Geriatric Nutritional Risk Index (GNRI). However, the association of the phenomenon with aging and GNRI has not yet been reported in detail. Further investigations are necessary to confirm and improve these findings. Similarly, discharged patient follow-up should be strengthened.

Caution should be exercised for the detection of SARS-CoV-2, especially in the elderly

In recent years, the prevalence and spread of coronavirus has had a huge impact on global public health. Due to the incomplete understanding of the pathogenic mechanism of the virus, it is difficult for humans to fight against the virus quickly and effectively once the outbreak occurs. In early 2020, a novel coronavirus was discovered in Wuhan, China. Soon after, similar cases were found in other countries around the world, and the number of infected people increased rapidly. So far, the global cumulative number of infected people has exceeded 3 million, and more than 200,000 people have died, which has had a huge impact on global human health and economic development. Every outbreak of disease makes a deep impression on mankind. Herein, we summarize the virology, epidemiology, clinical manifestations, diagnosis, treatment and prevention of SARS-CoV-2, and hope that countries can control the outbreak as soon as possible to minimize the loss.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): a review

BACKGROUND Shortly after its emergence in December 2019, the coronavirus disease 2019 (COVID-19) was declared as a pandemic by the World Health Organization. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the seventh member of the Coronaviridae family of viruses that causes disease in humans. THE PROBLEM Despite the established role of molecular diagnostics, COVID-19 serodiagnosis remains a poorly discovered and enigmatic area. Although there are numerous commercial serological products available globally, there is a severe paucity of high-quality peer-reviewed literature on their true performance characteristics. That being said, publications including in-house developed serological tests started to shed light on the kinetics of the humoral response. SUMMARY In spite of intense focus of assessing the performance characteristics of the commercially-available kits, the main issue remains rather invisible, that is, lack of solid science behind COVID-19 serology its clinical usefulness thereof. This short review summarizes the key points as to why COVID-19 is not jest ready to fly. PURPOSE OF REVIEW Despite having been mentioned as a testing option, COVID-19 serology has significant shortcomings that needs discussing. This short review is meant to shed light on one of those aspects.

Severe acute respiratory syndrome coronavirus 2, original antigenic sin, and antibody-dependent enhancement: ménage à trois.

The new coronavirus outbreak is an ongoing pandemic that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The new coronavirus SARS-Cov-2 belongs to the subfamily of ß-coronaviruses and shares 79.5% of the genetic sequence of SARS-CoV, the causative agent of the epidemic that started in 2002 and ended in 2004. Considering the clinical impact of the new outbreak, it is highly important to study the potential responses of the human immune system during the SARS-CoV-2 infection as well as the role of virus-specific T cells and by B-lymphocytes. Moreover, specific data on the production of IgG and IgM is crucial to allow the rapid identification of the infection. In this paper we also described the importance of sensitive and specific rapid test for SARS-CoV-2. Indeed, this test represents an important immunological tool aimed at identifying the precise phase of the infection in order to undertake a more appropriate pharmacological treatment. Lastly, we provided an overview of pharmacological treatments aimed to reduce inflammatory processes underlying the infection and the need for the discovery of a new vaccine against SARS-CoV-2.

SARS-Cov-2 infection: Response of human immune system and possible implications for the rapid test and treatment

The severe respiratory disease COVID-19 was initially reported in Wuhan, China, in December 2019, and spread into many provinces from Wuhan. The corresponding pathogen was soon identified as a novel coronavirus named SARS-CoV-2 (formerly, 2019-nCoV). As of 2 May, 2020, over 3 million COVID-19 cases had been confirmed, and 235,290 deaths had been reported globally, and the numbers are still increasing. It is important to understand the phylogenetic relationship between SARS-CoV-2 and known coronaviruses, and to identify its hosts for preventing the next round of emergency outbreak. In this study, we employ an effective alignment-free approach, the Natural Vector method, to analyze the phylogeny and classify the coronaviruses based on genomic and protein data. Our results show that SARS-CoV-2 is closely related to, but distinct from the SARS-CoV branch. By analyzing the genetic distances from the SARS-CoV-2 strain to the coronaviruses residing in animal hosts, we establish that the most possible transmission path originates from bats to pangolins to humans.

Analysis of the Hosts and Transmission Paths of SARS-CoV-2 in the COVID-19 Outbreak

The rapid spread of SARS-CoV-2, the causative agent of Coronavirus disease 2019 (COVID-19), has been accompanied by the emergence of distinct viral clades, though their clinical significance remains unclear. Here, we examined the genome sequences of 88 SARS-CoV-2 viruses from COVID-19 patients in Chicago, USA and identified three distinct phylogenetic clades. Clade 1 was most closely related to clades centered in New York, and showed evidence of rapid expansion across the USA, while Clade 3 was most closely related to those in Washington. Clade 2 was localized primarily to the Chicago area with limited evidence of expansion elsewhere. Average viral loads in the airways of patients infected with the rapidly spreading Clade 1 viruses were significantly higher than those of the poorly spreading Clade 2. These results show that multiple variants of SARS-CoV-2 are circulating in the USA that differ in their relative airway viral loads and potential for expansion.

A Unique Clade of SARS-CoV-2 Viruses is Associated with Lower Viral Loads in Patient Upper Airways

PURPOSE: The purpose of this study was to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA) in urine and blood specimens, and anal and oropharyngeal swabs from patients with confirmed SARS-CoV-2 infection, and correlated positive results with clinical findings. METHODS: Patients with confirmed SARS-CoV-2 infections were included in this study. Patients' demographic and clinical data were recorded. Quantitative real-time polymerase chain reaction was used to detect SARS-CoV-2 RNA in urine and blood specimens, and anal and oropharyngeal swabs. The study is registered at ClinicalTrials.gov (No. NCT04279782, 19 February, 2020). RESULTS: SARS-CoV-2 RNA was present in all four specimen types, though not all specimen types were positive simultaneously. The presence of viral RNA was not necessarily predictive of clinical symptoms, for example, the presence of viral RNA in the urine did not necessarily predict urinary tract symptoms. CONCLUSIONS: SARS-CoV-2 can infect multiple systems, including the urinary tract. Testing different specimen types may be useful for monitoring disease changes and progression, and for establishing a prognosis.

SARS-CoV-2 can be detected in urine, blood, anal swabs, and oropharyngeal swabs specimens

Nearly 400,000 people worldwide are known to have been infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) beginning in December 2019. The virus has now spread to over 168 countries including the United States, where the first cluster of cases was observed in the Seattle metropolitan area in Washington. Given the rapid increase in the number of cases in many localities, the availability of accurate, high-throughput SARS-CoV-2 testing is vital to efforts to manage the current public health crisis. In the course of optimizing SARS-CoV-2 testing performed by the University of Washington Clinical Virology Lab (UW Virology Lab), we evaluated assays using seven different primer-probe sets and one assay kit. We found that the most sensitive assays were those that used the E-gene primer-probe set described by Corman et al. (V. M. Corman, O. Landt, M. Kaiser, R. Molenkamp, et al., Euro Surveill 25:2000045, 2020, https://doi.org/10.2807/1560-7917.ES.2020.25.3.2000045) and the N2 set developed by the CDC (Division of Viral Diseases, Centers for Disease Control and Prevention, 2020, https://www.cdc.gov/coronavirus/2019-ncov/downloads/rt-pcr-panel-primer-probes.pdf). All assays tested were found to be highly specific for SARS-CoV-2, with no cross-reactivity with other respiratory viruses observed in our analyses regardless of the primer-probe set or kit used. These results will provide valuable information to other clinical laboratories who are actively developing SARS-CoV-2 testing protocols at a time when increased testing capacity is urgently needed worldwide.

Comparative Performance of SARS-CoV-2 Detection Assays Using Seven Different Primer-Probe Sets and One Assay Kit

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2 is the agent responsible for the coronavirus disease 2019 (COVID-19) global pandemic. SARS-CoV-2 is closely related to SARS-CoV, which caused the 2003 SARS outbreak but disappeared rapidly. Although numerous reagents were developed to study SARS-CoV infections, few have been applicable to evaluating SARS-CoV-2 infection and immunity. Current limitations in studying SARS-CoV-2 include few validated assays with fully replication-competent wild-type virus. We have developed protocols to propagate, quantify, and work with infectious SARS-CoV-2. Here, we describe: (1) virus stock generation, (2) RT-qPCR quantification of SARS-CoV-2 RNA; (3) detection of SARS-CoV-2 antigen by flow cytometry, (4) quantification of infectious SARS-CoV-2 by focus-forming and plaque assays; and 5) validated protocols for virus inactivation. Collectively, these methods can be adapted to a variety of experimental designs, which should accelerate our understanding of SARS-CoV-2 biology and the development of effective countermeasures against COVID-19.

Growth, detection, quantification, and inactivation of SARS-CoV-2

In December 2019, a pneumonia outbreak, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and presented a major threat to public health. Nationwide, there were more than 70,000 confirmed cases, and 2500 deaths. Most patients were elderly, with severe disease. For acute respiratory infection, RT-PCR is routinely used to detect causative viruses in respiratory secretions. Coronavirus RNA can be detected from nose and throat swabs, sputum and other lower respiratory tract secretions, blood and feces. Such specimens were examined by RT-PCR. Three targets, RdRP, E and N genes were detected, indicating samples were positive for SARS-CoV-2]. After patient recovery, a chest CT examination, combined with SARS-CoV-2 RNA detection, confirmed diagnosis. However, some recovery patients with negative RNA tests turned RNA positive. The preliminary data is about 14% of discharged patients in Guangdong reported by the Guangdong Center for Disease Control (CDC). This is an important scientific issue. If samples are positive for SARS-CoV-2 RNA, patients should be managed according to infection source. Fortunately, there were no close contacts of second-generation cases. We herein report six SARS-CoV-2 cases confirmed in our hospital, for the changes of results of SARS-CoV-2 RNA should attract attention. Most patients were elderly, with a low Geriatric Nutritional Risk Index (GNRI). However, the association of the phenomenon with aging and GNRI has not yet been reported in detail. Further investigations are necessary to confirm and improve these findings. Similarly, discharged patient follow-up should be strengthened. This article is protected by copyright. All rights reserved.

Caution should be exercised for the detection of SARS-CoV-2, especially in the elderly.

The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from the Hubei province in China in late 2019 demonstrates the epidemic potential of coronaviruses. The rapid spread of this virus across the world in only 2 months highlights the transmissibility of this family of viruses and the significant morbidity and mortality that they can cause. We highlight the current state of knowledge of coronavirus biology while answering questions concerning the current outbreak of SARS-CoV-2.

COVID-19: Knowns, Unknowns, and Questions

BACKGROUND: The pneumonia caused by the 2019 novel coronavirus (SARS-CoV-2, also called 2019-nCoV) recently break out in Wuhan, China, and was named as COVID-19. With the spread of the disease, similar cases have also been confirmed in other regions of China. We aimed to report the imaging and clinical characteristics of these patients infected with SARS-CoV-2 in Guangzhou, China. METHODS: All patients with laboratory-identified SARS-CoV-2 infection by real-time polymerase chain reaction (PCR) were collected between January 23, 2020, and February 4, 2020, in a designated hospital (Guangzhou Eighth People's Hospital). This analysis included 90 patients (39 men and 51 women; median age, 50 years (age range, 18-86 years). All the included SARS-CoV-2-infected patients underwent non-contrast enhanced chest computed tomography (CT). We analyzed the clinical characteristics of the patients, as well as the distribution characteristics, pattern, morphology, and accompanying manifestations of lung lesions. In addition, after 1-6 days (mean 3.5 days), follow-up chest CT images were evaluated to assess radiological evolution. FINDINGS: The majority of infected patients had a history of exposure in Wuhan or to infected patients and mostly presented with fever and cough. More than half of the patients presented bilateral, multifocal lung lesions, with peripheral distribution, and 53 (59%) patients had more than two lobes involved. Of all included patients, COVID-19 pneumonia presented with ground glass opacities in 65 (72%), consolidation in 12 (13%), crazy paving pattern in 11 (12%), interlobular thickening in 33 (37%), adjacent pleura thickening in 50 (56%), and linear opacities combined in 55 (61%). Pleural effusion, pericardial effusion, and lymphadenopathy were uncommon findings. In addition, baseline chest CT did not show any abnormalities in 21 patients (23%), but 3 patients presented bilateral ground glass opacities on the second CT after 3-4 days. CONCLUSION: SARS-CoV-2 infection can be confirmed based on the patient's history, clinical manifestations, imaging characteristics, and laboratory tests. Chest CT examination plays an important role in the initial diagnosis of the novel coronavirus pneumonia. Multiple patchy ground glass opacities in bilateral multiple lobular with periphery distribution are typical chest CT imaging features of the COVID-19 pneumonia.

Imaging and clinical features of patients with 2019 novel coronavirus SARS-CoV-2

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused considerable disruption across the world, resulting in more than 235,000 deaths since December 2019. SARS-CoV-2 has a wide tropism and detection of the virus has been described in multiple specimen types, including various respiratory secretions, cerebrospinal fluid, and stool. OBJECTIVE: To evaluate the accuracy and sensitivity of a laboratory modified CDCbased SARS-CoV-2 N1 and N2 assay across a range of sample types. Study Design We compared the matrix effect on the analytical sensitivity of SARS-CoV-2 detection by qRT-PCR in nasal swabs collected in viral transport medium (VTM), bronchoalveolar lavage (BAL), sputum, plasma, cerebral spinal fluid (CSF), stool, VTM, phosphate buffered saline (PBS), and Hanks' Balanced Salt Solution (HBSS). Initial limits of detection (LoD) were subsequently narrowed to confirm an LoD for each specimen type and target gene. RESULTS: LoDs were established using a modified CDC-based laboratory developed test and ranged from a mean CT cut-off of 33.8-35.7 (10-20 copies/reaction) for the N1 gene target, and 34.0-36.2 (1-10 copies/reaction) for N2. Alternatives to VTM such as PBS and HBSS had comparable LoDs. The N2 gene target was found to be most sensitive in CSF. CONCLUSION: A modified CDC-based laboratory developed test is able to detect SARSCoV- 2 accurately with similar sensitivity across all sample types tested.

Validation of SARS-CoV-2 detection across multiple specimen types

A cluster of severe pneumonia of unknown etiology in Wuhan City, Hubei province in China emerged in December 2019. A novel coronavirus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was isolated from lower respiratory tract sample as the causative agent. The current outbreak of infections with SARS-CoV-2 is termed Coronavirus Disease 2019 (COVID-19) by the World Health Organization (WHO). COVID-19 rapidly spread into at least 114 countries and killed more than 4,000 people by March 11 2020. WHO officially declared COVID-19 a pandemic on March 11, 2020. There have been two novel coronavirus outbreaks in the past two decades. The 2002-2003 outbreak of severe acute respiratory syndrome (SARS) in 2002-2003 caused by SARS-CoV had a case fatality rate of around 10% (8,098 confirmed cases and 774 death), while Middle East respiratory syndrome (MERS) caused by MERS-CoV killed 861 people out of a total 2,502 confirmed cases between 2012 and 2019. The purpose of this review is to summarize known-to-date information about SARS-CoV-2, transmission of SARS-CoV-2, and clinical features.

Epidemiology, virology, and clinical features of severe acute respiratory syndrome -coronavirus-2 (SARS-CoV-2; Coronavirus Disease-19)

The SARS-CoV-2 is a new human coronavirus candidate recently detected in China that is now reported in people on inhabited continents. The virus shares a high level of identity with some bat coronaviruses and is recognised as a potentially zoonotic virus. We are utilizing the One Health concept to understand the emergence of the virus, as well as to point to some possible control strategies that might reduce the spread of the virus across the globe; thus, containment of such virus would be possible.

The SARS-CoV-2 outbreak from a one health perspective

A novel coronavirus SARS-CoV-2 was identified in Wuhan, Hubei Province, China in December of 2019. According to WHO report, this new coronavirus has resulted in 76,392 confirmed infections and 2,348 deaths in China by 22 February, 2020, with additional patients being identified in a rapidly growing number internationally. SARS-CoV-2 was reported to share the same receptor, Angiotensin-converting enzyme 2 (ACE2), with SARS-CoV. Here based on the public database and the state-of-the-art single-cell RNA-Seq technique, we analyzed the ACE2 RNA expression profile in the normal human lungs. The result indicates that the ACE2 virus receptor expression is concentrated in a small population of type II alveolar cells (AT2). Surprisingly, we found that this population of ACE2-expressing AT2 also highly expressed many other genes that positively regulating viral entry, reproduction and transmission. This study provides a biological background for the epidemic investigation of the COVID-19, and could be informative for future anti-ACE2 therapeutic strategy development.

Single-cell RNA expression profiling of ACE2,thereceptor of SARS-CoV-2

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; previously provisionally named 2019 novel coronavirus or 2019-nCoV) disease (COVID-19) in China at the end of 2019 has caused a large global outbreak and is a major public health issue. As of 11 February 2020, data from the World Health Organization (WHO) have shown that more than 43 000 confirmed cases have been identified in 28 countries/regions, with >99% of cases being detected in China. On 30 January 2020, the WHO declared COVID-19 as the sixth public health emergency of international concern. SARS-CoV-2 is closely related to two bat-derived severe acute respiratory syndrome-like coronaviruses, bat-SL-CoVZC45 and bat-SL-CoVZXC21. It is spread by human-to-human transmission via droplets or direct contact, and infection has been estimated to have mean incubation period of 6.4 days and a basic reproduction number of 2.24–3.58. Among patients with pneumonia caused by SARS-CoV-2 (novel coronavirus pneumonia or Wuhan pneumonia), fever was the most common symptom, followed by cough. Bilateral lung involvement with ground-glass opacity was the most common finding from computed tomography images of the chest. The one case of SARS-CoV-2 pneumonia in the USA is responding well to remdesivir, which is now undergoing a clinical trial in China. Currently, controlling infection to prevent the spread of SARS-CoV-2 is the primary intervention being used. However, public health authorities should keep monitoring the situation closely, as the more we can learn about this novel virus and its associated outbreak, the better we can respond.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges

COVID-19 is a viral respiratory illness caused by a new coronavirus called SARS-CoV-2. The World Health Organization declared the SARS-CoV-2 outbreak a global public health emergency. We performed genetic analyses of eighty-six complete or near-complete genomes of SARS-CoV-2 and revealed many mutations and deletions on coding and non-coding regions. These observations provided evidence of the genetic diversity and rapid evolution of this novel coronavirus.

Genetic diversity and evolution of SARS-CoV-2

SARS-CoV-2 is a betacoronavirus that is responsible for the COVID-19 pandemic. The genome of SARS-CoV-2 was reported recently, but its transcriptomic architecture is unknown. Utilizing two complementary sequencing techniques, we here present a high-resolution map of the SARS-CoV-2 transcriptome and epitranscriptome. DNA nanoball sequencing shows that the transcriptome is highly complex owing to numerous recombination events, both canonical and noncanonical. In addition to the genomic RNA and subgenomic RNAs common in all coronaviruses, SARS-CoV-2 produces a large number of transcripts encoding unknown ORFs with fusion, deletion, and/or frameshift. Using nanopore direct RNA sequencing, we further find at least 41 RNA modification sites on viral transcripts, with the most frequent motif being AAGAA. Modified RNAs have shorter poly(A) tails than unmodified RNAs, suggesting a link between the internal modification and the 3′ tail. Functional investigation of the unknown ORFs and RNA modifications discovered in this study will open new directions to our understanding of the life cycle and pathogenicity of SARS-CoV-2. Highlights We provide a high-resolution map of SARS-CoV-2 transcriptome and epitranscriptome using nanopore direct RNA sequencing and DNA nanoball sequencing. The transcriptome is highly complex owing to numerous recombination events, both canonical and noncanonical. In addition to the genomic and subgenomic RNAs common in all coronaviruses, SARS-CoV-2 produces transcripts encoding unknown ORFs. We discover at least 41 potential RNA modification sites with an AAGAA motif.

The architecture of SARS-CoV-2 transcriptome

SARS-CoV-2 is the cause of the worldwide outbreak of COVID-19 that has been characterized as a pandemic by the WHO. Since the first report of COVID-19 on December 31, 2019, 179,111 cases were confirmed in 160 countries/regions with 7,426 deaths as of March 17, 2020. However, there have been no vaccines approved in the world to date. In this study, we analyzed the biological characteristics of the SARS-CoV-2 Spike protein, Pro330-Leu650 (SARS-CoV-2-SPL), using biostatistical methods. SARS-CoV-2-SPL possesses a receptor-binding region (RBD) and important B (Ser438-Gln506, Thr553-Glu583, Gly404-Aps427, Thr345-Ala352, and Lys529-Lys535) and T (9 CD4 and 11 CD8 T cell antigenic determinants) cell epitopes. High homology in this region between SARS-CoV-2 and SARS-CoV amounted to 87.7%, after taking the biological similarity of the amino acids into account and eliminating the receptor-binding motif (RBM). The overall topology indicated that the complete structure of SARS-CoV-2-SPL was with RBM as the head, and RBD as the trunk and the tail region. SARS-CoV-2-SPL was found to have the potential to elicit effective B and T cell responses. Our findings may provide meaningful guidance for SARS-CoV-2 vaccine design.

The biological characteristics of SARS-CoV-2 Spike protein Pro330-Leu650

SARS-CoV-2 is the cause of the worldwide outbreak of COVID-19 that has been characterized as a pandemic by the WHO. Since the first report of COVID-19 on December 31, 2019, 179,111 cases were confirmed in 160 countries/regions with 7426 deaths as of March 17, 2020. However, there have been no vaccines approved in the world to date. In this study, we analyzed the biological characteristics of the SARS-CoV-2 Spike protein, Pro330-Leu650 (SARS-CoV-2-SPL), using biostatistical methods. SARS-CoV-2-SPL possesses a receptor-binding region (RBD) and important B (Ser438-Gln506, Thr553-Glu583, Gly404-Aps427, Thr345-Ala352, and Lys529-Lys535) and T (9 CD4 and 11 CD8 T cell antigenic determinants) cell epitopes. High homology in this region between SARS-CoV-2 and SARS-CoV amounted to 87.7%, after taking the biological similarity of the amino acids into account and eliminating the receptor-binding motif (RBM). The overall topology indicated that the complete structure of SARS-CoV-2-SPL was with RBM as the head, and RBD as the trunk and the tail region. SARS-CoV-2-SPL was found to have the potential to elicit effective B and T cell responses. Our findings may provide meaningful guidance for SARS-CoV-2 vaccine design.

The biological characteristics of SARS-CoV-2 spike protein Pro330-Leu650

In late 2019, a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, the capital of the Chinese province Hubei. Since then, SARS-CoV-2 has been responsible for a worldwide pandemic resulting in over 4 million infections and over 250,000 deaths. The pandemic has instigated widespread research related to SARS-CoV-2 and the disease that it causes, COVID-19. Research into this new virus will be facilitated by the availability of clearly described and effective procedures that enable the propagation and quantification of infectious virus. As work with the virus is recommended to be performed at biosafety level 3, validated methods to effectively inactivate the virus to enable the safe study of RNA, DNA, and protein from infected cells are also needed. Here, we report methods used to grow SARS-CoV-2 in multiple cell lines and to measure virus infectivity by plaque assay using either agarose or microcrystalline cellulose as an overlay as well as a SARS-CoV-2 specific focus forming assay. We also demonstrate effective inactivation by TRIzol, 10% neutral buffered formalin, beta propiolactone, and heat.

Propagation, Inactivation, and Safety Testing of SARS-CoV-2.

SARS-CoV-2, the novel coronavirus from China, is spreading around the world, causing a huge reaction despite its current low incidence outside China and the Far East. Four common coronaviruses are in current circulation and cause millions of cases worldwide. This article compares the incidence and mortality rates of these four common coronaviruses with those of SARS-CoV-2 in Organisation for Economic Co-operation and Development countries. It is concluded that the problem of SARS-CoV-2 is probably being overestimated, as 2.6 million people die of respiratory infections each year compared with less than 4000 deaths for SARS-CoV-2 at the time of writing.

SARS-CoV-2: fear versus data

Background Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused considerable disruption across the world, resulting in more than 235,000 deaths since December 2019. SARS-CoV-2 has a wide tropism and detection of the virus has been described in multiple specimen types, including various respiratory secretions, cerebrospinal fluid, and stool. Objective To evaluate the accuracy and sensitivity of a laboratory modified CDCbased SARS-CoV-2 N1 and N2 assay across a range of sample types. Study Design We compared the matrix effect on the analytical sensitivity of SARS-CoV-2 detection by qRT-PCR in nasal swabs collected in viral transport medium (VTM), bronchoalveolar lavage (BAL), sputum, plasma, cerebral spinal fluid (CSF), stool, VTM, phosphate buffered saline (PBS), and Hanks' Balanced Salt Solution (HBSS). Initial limits of detection (LoD) were subsequently narrowed to confirm an LoD for each specimen type and target gene. Results LoDs were established using a modified CDC-based laboratory developed test and ranged from a mean CT cut-off of 33.8-35.7 (10-20 copies/reaction) for the N1 gene target, and 34.0-36.2 (1-10 copies/reaction) for N2. Alternatives to VTM such as PBS and HBSS had comparable LoDs. The N2 gene target was found to be most sensitive in CSF. Conclusion A modified CDC-based laboratory developed test is able to detect SARSCoV- 2 accurately with similar sensitivity across all sample types tested.

Validation of SARS-CoV-2 detection across multiple specimen types.

Coronaviruses are a well-known cause of upper and lower respiratory disease, and since 2002 have been a recognized source of potential pandemic spread. Over the past two decades, since the Severe Acute Respiratory Syndrome (SARS) outbreak, a large body of research has accumulated on the virology, clinical symptoms and signs, and experimental treatments of Coronaviruses. In 2020, a new form of Coronaviruses (SARS-CoV-2) emerged and spread rapidly throughout the globe. Given the wide-ranging clinical presentations of those infected with SARS-CoV-2, other viruses might be overlooked when evaluating at-risk patients. Furthermore, due to suboptimal testing capabilities, an early clinical diagnosis is not always possible. Here, we present a case of a patient with pneumonia thought to be caused by SARS-CoV-2 only to be found to have another Coronavirus. This emphasizes the need to be vigilant when evaluating patients with viral-like respiratory infections.

Endemic and emerging coronavirus pulmonary infections.

Despite initial findings indicating that SARS-CoV and SARS-CoV-2 are genetically related belonging to the same virus species and that the two viruses used the same entry receptor, angiotensin-converting enzyme 2 (ACE2), our data demonstrated that there is no detectable cross-neutralization by SARS patient sera against SARS-CoV-2. We also found that there are significant levels of neutralizing antibodies in recovered SARS patients 9–17 years after initial infection. These findings will be of significant use in guiding the development of serologic tests, formulating convalescent plasma therapy strategies, and assessing the longevity of protective immunity for SARS-related coronaviruses in general as well as vaccine efficacy.

Lack of cross-neutralization by SARS patient sera towards SARS-CoV-2

We sequenced four severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes from Malaysia during the second wave of infection and found unique mutations which suggest local evolution. Circulating Malaysian strains represent introductions from different countries, particularly during the first wave of infection. Genome sequencing is important for understanding local epidemiology.

Complete Genome Sequences of SARS-CoV-2 Strains Detected in Malaysia

A newly emerged coronavirus, SARS-CoV-2, caused severe pneumonia outbreaks in China in December 2019 and has since spread to various countries around the world. To trace the evolution route and probe the transmission dynamics of this virus, we performed phylodynamic analysis of 247 high quality genomic sequences available in the GISAID platform as of 5 March 2020. Among them, four genetic clusters, defined as super-spreaders (SSs), could be identified and were found to be responsible for the major outbreaks that subsequently occurred in various countries. SS1 was widely disseminated in Asia and the US, and mainly responsible for outbreaks in the states of Washington and California as well as South Korea, whereas SS4 contributed to the pandemic in Europe. Using the signature mutations of each SS as markers, we further analysed 1539 genome sequences reported after 29 February 2020 and found that 90% of these genomes belonged to SSs, with SS4 being the most dominant. The relative degree of contribution of each SS to the pandemic in different continents was also depicted. Identification of these super-spreaders greatly facilitates development of new strategies to control the transmission of SARS-CoV-2.

Genetic cluster analysis of SARS-CoV-2 and the identification of those responsible for the major outbreaks in various countries.

Coronavirus disease-19 (COVID-19) pandemic has emerged as one of the major outbreaks to be mentioned in history in coming times. Like Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a respiratory virus infecting the lungs with fever, dry cough and acute pneumonia being the major symptoms. It infects the epithelial cells expressing Angiotensin converting enzyme 2 (ACE2) receptor, which is crucial for the viral entry. Based on evolving clinical evidence, it is now unfitting to label SARS-CoV-2 as just a respiratory virus, as lately there are various reports that substantiate its pathogenicity in other organs of the body, including brain. In this review, we discuss the epidemiology of SARS-CoV-2 in comparison to SARS and MERS along with possibilities of viral entry into central nervous system (CNS) tissues. The review provides detailed information about the virulence, epidemiology and insights into molecular pathways involved in the infectivity of the SARS-CoV-2 virus, along with in-depth view of current concepts about the neurological significance of the SARS-CoV-2 virus and its neuropathological competence. The review also touches upon our current understanding of placental transmission of SARS-CoV-2, an important aspect of vertical transmission. Furthermore, the review provides the current update on strategies that have been used, being used or under trial for treating the disease.

SARS-CoV-2 more than a respiratory virus: Its potential role in neuropathogenesis.

Since December 2019, the emergence of the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) infection has been reported unexpectedly in Wuhan, China, with staggering infection speed across China and around the world To date, seven known strains of HCoVs belonging to four genera (i e , alpha?, beta?, gamma, and delta-CoV) have been recognized;the latest one has been identified as the SARS-CoV-2 Although the common transmission routes of SARS-CoV-2 is the respiratory tract, it seems that other routes such as the gastrointestinal tract may be effective for the entry of the virus in the body Although there are no biological markers to predict the susceptibility of humans to COVID-19, several risk factors have been identified to predict the susceptibility of patients to COVID-19 Initial data revealed that males, pregnant women, elderly, and underlying conditions predispose patients to higher morbidity or mortality and also might be at risk for a severe infection of COVID-19 There is a greater need to better understand the mechanisms and risk factors of transmission routes To date, despite the whole world effort to review various aspects of SARS-CoV-2, including epidemiology, clinical manifestations, diagnosis, and treatment options, there are still gaps in the knowledge of this disease and many issues remain unclear Therefore, there is an urgent need for update data on SARS-CoV-2 Here, this study provide the current epidemiological status (transmission routes and risk of transmission, possible origins and source, mortality and morbidity risk, and geographical distribution) of the SARS-CoV-2 in the world in 2020

Emerging coronaviruses: first SARS, second MERS and third SARS-CoV-2: epidemiological updates of COVID-19

COVID-19 has effectively spread worldwide. As of May 2020, Turkey is among the top ten countries with the most cases. A comprehensive genomic characterization of the virus isolates in Turkey is yet to be carried out. Here, we built a phylogenetic tree with globally obtained 15,277 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes. We identified the subtypes based on the phylogenetic clustering in comparison with the previously annotated classifications. We performed a phylogenetic analysis of the first thirty SARS-CoV-2 genomes isolated and sequenced in Turkey. We suggest that the first introduction of the virus to the country is earlier than the first reported case of infection. Virus genomes isolated from Turkey are dispersed among most types in the phylogenetic tree. We find two of the seventeen sub-clusters enriched with the isolates of Turkey, which likely have spread expansively in the country. Finally, we traced virus genomes based on their phylogenetic placements. This analysis suggested multiple independent international introductions of the virus and revealed a hub for the inland transmission. We released a web application to track the global and interprovincial virus spread of the isolates from Turkey in comparison to thousands of genomes worldwide.

Phylogenetic Analysis of SARS-CoV-2 Genomes in Turkey

Coronavirus disease-19 (COVID-19) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is now a pandemic threat. This virus is supposed to be spread by human to human transmission. Cellular angiotensin-converting enzyme 2 (ACE2) is the receptor of SARS-CoV-2 which is identical or similar in different species of animals such as pigs, ferrets, cats, orangutans, monkeys, and humans. Moreover, a recent study predicted that dogs might be secondary hosts during the evolution of SARS-CoV-2 from bat to human. Therefore, there is a possibility of spreading SARS-CoV-2 through domestic pets. There are now many reports of SARS-CoV-2 positive cases in dogs, cats, tigers, lion, and minks. Experimental data showed ferrets and cats are highly susceptible to SARS-CoV-2 as infected by virus inoculation and can transmit the virus directly or indirectly by droplets or airborne routes. Based on these natural infection reports and experimental data, whether the pets are responsible for SARS-CoV-2 spread to humans; needs to be deeply investigated. Humans showing clinical symptoms of respiratory infections have been undergoing for the COVID-19 diagnostic test but many infected people and few pets confirmed with SARS-CoV-2 remained asymptomatic. In this review, we summarize the natural cases of SARS-CoV-2 in animals with the latest researches conducted in this field. This review will be helpful to think insights of SARS-CoV-2 transmissions, spread, and demand for seroprevalence studies, especially in companion animals.

SARS-CoV-2 host diversity: An update of natural infections and experimental evidence

We sequenced the 29,751-base genome of the severe acute respiratory syndrome (SARS)-associated coronavirus known as the Tor2 isolate. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses, including two human coronaviruses, HCoV-OC43 and HCoV-229E. Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of coronaviruses. The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using polymerase chain reaction and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.

The Genome sequence of the SARS-associated coronavirus.

In December 2019, some cases of viral pneumonia were epidemiologically related to a new coronavirus in the province of Hubei, China. Subsequently, there has been an increase in infections attributable to this virus throughout China and worldwide. The World Health Organization (WHO) has officially named the infection coronavirus disease 2019 (COVID-19), and the virus has been classified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This appears to be a virus from Rhinolophus bats, but the intermediate host has not yet been identified. The mechanism of infection of SARS-CoV-2 is not yet known; it appears to have affinity for cells located in the lower airways, where it replicates. The interhuman transmission of coronaviruses mainly occurs through saliva droplets and direct and indirect contact via surfaces. As of March 10, 2020, the number of cases worldwide was 113,702. Along with severe acute respiratory syndrome (SARS) and Middle Eastern respiratory syndrome (MERS), COVID-19 appears to cause a severe clinical picture in humans, ranging from mild malaise to death by sepsis/acute respiratory distress syndrome. The prognosis is worse in elderly patients with comorbidities. To date, there is no specific therapy for COVID-19. Prevention of SARS-CoV-2 infection implies strategies that limit the spread of the virus. WHO and other international and national bodies have developed continuously updated strategic objectives and provisions to contain the spread of the virus and infection.

Coronavirus: Update Related to the Current Outbreak of COVID-19.