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1.
Bioessays ; 42(10): e2000091, 2020 10.
Article in English | MEDLINE | ID: covidwho-2074923

ABSTRACT

Despite claims from prominent scientists that SARS-CoV-2 indubitably emerged naturally, the etiology of this novel coronavirus remains a pressing and open question: Without knowing the true nature of a disease, it is impossible for clinicians to appropriately shape their care, for policy-makers to correctly gauge the nature and extent of the threat, and for the public to appropriately modify their behavior. Unless the intermediate host necessary for completing a natural zoonotic jump is identified, the dual-use gain-of-function research practice of viral serial passage should be considered a viable route by which the novel coronavirus arose. The practice of serial passage mimics a natural zoonotic jump, and offers explanations for SARS-CoV-2's distinctive spike-protein region and its unexpectedly high affinity for angiotensin converting enzyme (ACE2), as well as the notable polybasic furin cleavage site within it. Additional molecular clues raise further questions, all of which warrant full investigation into the novel coronavirus's origins and a re-examination of the risks and rewards of dual-use gain-of-function research.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/etiology , Coronavirus Infections/transmission , Pneumonia, Viral/etiology , Pneumonia, Viral/transmission , Zoonoses/transmission , Amino Acid Sequence , Angiotensin-Converting Enzyme 2 , Animals , Betacoronavirus/growth & development , COVID-19 , Gain of Function Mutation/genetics , Humans , Pandemics , Peptidyl-Dipeptidase A/metabolism , Protein Binding , SARS-CoV-2 , Serial Passage , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Zoonoses/virology
2.
Virus Res ; 319: 198882, 2022 Oct 02.
Article in English | MEDLINE | ID: covidwho-2061967

ABSTRACT

To date, a total of seven human coronaviruses (HCoVs) have been identified, all of which are important respiratory pathogens. Recently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has led to a global pandemic causing millions of infections and deaths. Here, we summarize the discovery and fundamental virology of HCoVs, discuss their zoonotic transmission and highlight the weak species barrier of SARS-CoV-2. We also discuss the possible origins of SARS-CoV-2 variants of concern identified to date and discuss the experimental challenges in characterizing mutations of interest and propose methods to circumvent them. As the COVID-19 treatment and prevention landscape rapidly evolves, we summarize current therapeutics and vaccines, and their implications on SARS-CoV-2 variants. Finally, we explore how interspecies transmission of SARS-CoV-2 may drive the emergence of novel strains, how disease severity may evolve and how COVID-19 will likely continue to burden healthcare systems globally.


Subject(s)
COVID-19 , Coronavirus Infections , Pneumonia, Viral , Betacoronavirus/genetics , COVID-19/drug therapy , Coronavirus Infections/drug therapy , Humans , Pneumonia, Viral/prevention & control , SARS-CoV-2/genetics
3.
Viruses ; 14(7)2022 Jun 25.
Article in English | MEDLINE | ID: covidwho-1911654

ABSTRACT

Coronaviruses are well known as a diverse family of viruses that affect a wide range of hosts. Since the outbreak of severe acute respiratory syndrome, a variety of bat-associated coronaviruses have been identified in many countries. However, they do not represent all the specific geographic locations of their hosts. In this study, full-length genomes representing newly identified bat coronaviruses in South Korea were obtained using an RNA sequencing approach. The analysis, based on genome structure, conserved replicase domains, spike gene, and nucleocapsid genes revealed that bat Alphacoronaviruses are from three different viral species. Among them, the newly identified B20-97 strain may represent a new putative species, closely related to PEDV. In addition, the newly-identified MERS-related coronavirus exhibited shared genomic nucleotide identities of less than 76.4% with other Merbecoviruses. Recombination analysis and multiple alignments of spike and RBD amino acid sequences suggested that this strain underwent recombination events and could possibly use hDPP4 molecules as its receptor. The bat SARS-related CoV B20-50 is unlikely to be able to use hACE2 as its receptor and lack of an open reading frame in ORF8 gene region. Our results illustrate the diversity of coronaviruses in Korean bats and their evolutionary relationships. The evolution of the bat coronaviruses related ORF8 accessory gene is also discussed.


Subject(s)
Alphacoronavirus , Chiroptera , Coronaviridae , Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , SARS Virus , Alphacoronavirus/genetics , Animals , Betacoronavirus/genetics , Coronaviridae/genetics , Genome, Viral , Genomics , Middle East Respiratory Syndrome Coronavirus/genetics , Phylogeny , SARS Virus/genetics
6.
Crit Rev Microbiol ; 46(6): 689-702, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-1730391

ABSTRACT

Intensive worldwide efforts are underway to determine both the pathogenesis of SARS-CoV-2 infection and the immune responses in COVID-19 patients in order to develop effective therapeutics and vaccines. One type of cell that may contribute to these immune responses is the γδ T lymphocyte, which plays a key role in immunosurveillance of the mucosal and epithelial barriers by rapidly responding to pathogens. Although found in low numbers in blood, γδ T cells consist the majority of tissue-resident T cells and participate in the front line of the host immune defense. Previous studies have demonstrated the critical protective role of γδ T cells in immune responses to other respiratory viruses, including SARS-CoV-1. However, no studies have profoundly investigated these cells in COVID-19 patients to date. γδ T cells can be safely expanded in vivo using existing inexpensive FDA-approved drugs such as bisphosphonate, in order to test its protective immune response to SARS-CoV-2. To support this line of research, we review insights gained from previous coronavirus research, along with recent findings, discussing the potential role of γδ T cells in controlling SARS-CoV-2. We conclude by proposing several strategies to enhance γδ T cell's antiviral function, which may be used in developing therapies for COVID-19.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , T-Lymphocyte Subsets/immunology , Animals , Betacoronavirus/genetics , COVID-19 , Coronavirus Infections/virology , Humans , Pandemics , Pneumonia, Viral/virology , SARS-CoV-2 , Virus Replication
7.
Indian J Med Res ; 151(2 & 3): 200-209, 2020.
Article in English | MEDLINE | ID: covidwho-1726321

ABSTRACT

Background & objectives: Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has globally affected 195 countries. In India, suspected cases were screened for SARS-CoV-2 as per the advisory of the Ministry of Health and Family Welfare. The objective of this study was to characterize SARS-CoV-2 sequences from three identified positive cases as on February 29, 2020. Methods: Throat swab/nasal swab specimens for a total of 881 suspected cases were screened by E gene and confirmed by RdRp (1), RdRp (2) and N gene real-time reverse transcription-polymerase chain reactions and next-generation sequencing. Phylogenetic analysis, molecular characterization and prediction of B- and T-cell epitopes for Indian SARS-CoV-2 sequences were undertaken. Results: Three cases with a travel history from Wuhan, China, were confirmed positive for SARS-CoV-2. Almost complete (29,851 nucleotides) genomes of case 1, case 3 and a fragmented genome for case 2 were obtained. The sequences of Indian SARS-CoV-2 though not identical showed high (~99.98%) identity with Wuhan seafood market pneumonia virus (accession number: NC 045512). Phylogenetic analysis showed that the Indian sequences belonged to different clusters. Predicted linear B-cell epitopes were found to be concentrated in the S1 domain of spike protein, and a conformational epitope was identified in the receptor-binding domain. The predicted T-cell epitopes showed broad human leucocyte antigen allele coverage of A and B supertypes predominant in the Indian population. Interpretation & conclusions: The two SARS-CoV-2 sequences obtained from India represent two different introductions into the country. The genetic heterogeneity is as noted globally. The identified B- and T-cell epitopes may be considered suitable for future experiments towards the design of vaccines and diagnostics. Continuous monitoring and analysis of the sequences of new cases from India and the other affected countries would be vital to understand the genetic evolution and rates of substitution of the SARS-CoV-2.


Subject(s)
Betacoronavirus/genetics , Genome, Viral , COVID-19 , Coronavirus Infections , Epitopes, B-Lymphocyte/genetics , Epitopes, T-Lymphocyte/genetics , Humans , India , Models, Molecular , Pandemics , Phylogeny , Pneumonia, Viral , Protein Structure, Tertiary , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics
8.
Viruses ; 12(6)2020 06 25.
Article in English | MEDLINE | ID: covidwho-1726024

ABSTRACT

The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide has highlighted the importance of reliable and rapid diagnostic testing to prevent and control virus circulation. Dozens of monoplex in-house RT-qPCR assays are already available; however, the development of dual-target assays is suited to avoid false-negative results caused by polymorphisms or point mutations, that can compromise the accuracy of diagnostic and screening tests. In this study, two mono-target assays recommended by WHO (E-Sarbeco (enveloppe gene, Charite University, Berlin, Germany) and RdRp-IP4 (RdRp, Institut Pasteur, Paris, France)) were selected and combined in a unique robust test; the resulting duo SARS-CoV-2 RT-qPCR assay was compared to the two parental monoplex tests. The duo SARS-CoV-2 assay performed equally, or better, in terms of sensitivity, specificity, linearity and signal intensity. We demonstrated that combining two single systems into a dual-target assay (with or without an MS2-based internal control) did not impair performances, providing a potent tool adapted for routine molecular diagnosis in clinical microbiology laboratories.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , RNA-Dependent RNA Polymerase/genetics , Real-Time Polymerase Chain Reaction/methods , Viral Envelope Proteins/genetics , Viral Nonstructural Proteins/genetics , Betacoronavirus/genetics , COVID-19 , Coronavirus Envelope Proteins , Coronavirus Infections/virology , Coronavirus RNA-Dependent RNA Polymerase , Humans , Pandemics , Pneumonia, Viral/virology , RNA, Viral/analysis , SARS-CoV-2 , Sensitivity and Specificity , World Health Organization
9.
Viruses ; 12(6)2020 06 08.
Article in English | MEDLINE | ID: covidwho-1726020

ABSTRACT

Clinical samples collected in coronavirus disease 19 (COVID-19), patients are commonly manipulated in biosafety level 2 laboratories for molecular diagnostic purposes. Here, we tested French norm NF-EN-14476+A2 derived from European standard EN-14885 to assess the risk of manipulating infectious viruses prior to RNA extraction. SARS-CoV-2 cell-culture supernatant and nasopharyngeal samples (virus-spiked samples and clinical samples collected in COVID-19 patients) were used to measure the reduction of infectivity after 10 minute contact with lysis buffer containing various detergents and chaotropic agents. A total of thirteen protocols were evaluated. Two commercially available formulations showed the ability to reduce infectivity by at least 6 log 10, whereas others proved less effective.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/virology , Pneumonia, Viral/virology , Virus Inactivation/drug effects , Animals , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , Betacoronavirus/physiology , COVID-19 , Cell Culture Techniques/methods , Chlorocebus aethiops , Containment of Biohazards/methods , Containment of Biohazards/standards , Humans , Nasopharynx/virology , Pandemics , RNA, Viral/isolation & purification , SARS-CoV-2 , Specimen Handling/methods , Vero Cells , Viral Load/methods
10.
Viruses ; 12(5)2020 04 30.
Article in English | MEDLINE | ID: covidwho-1726009

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which first occurred in Wuhan (China) in December of 2019, causes a severe acute respiratory illness with a high mortality rate, and has spread around the world. To gain an understanding of the evolution of the newly emerging SARS-CoV-2, we herein analyzed the codon usage pattern of SARS-CoV-2. For this purpose, we compared the codon usage of SARS-CoV-2 with that of other viruses belonging to the subfamily of Orthocoronavirinae. We found that SARS-CoV-2 has a high AU content that strongly influences its codon usage, which appears to be better adapted to the human host. We also studied the evolutionary pressures that influence the codon usage of five conserved coronavirus genes encoding the viral replicase, spike, envelope, membrane and nucleocapsid proteins. We found different patterns of both mutational bias and natural selection that affect the codon usage of these genes. Moreover, we show here that the two integral membrane proteins (matrix and envelope) tend to evolve slowly by accumulating nucleotide mutations on their corresponding genes. Conversely, genes encoding nucleocapsid (N), viral replicase and spike proteins (S), although they are regarded as are important targets for the development of vaccines and antiviral drugs, tend to evolve faster in comparison to the two genes mentioned above. Overall, our results suggest that the higher divergence observed for the latter three genes could represent a significant barrier in the development of antiviral therapeutics against SARS-CoV-2.


Subject(s)
Betacoronavirus/genetics , Codon , Coronavirus/genetics , Genome, Viral , Base Composition , Betacoronavirus/chemistry , Betacoronavirus/physiology , Biological Evolution , Coronavirus/classification , Genes, Viral , Host Specificity , Mutation , Phylogeny , SARS-CoV-2
11.
Viruses ; 12(5)2020 04 26.
Article in English | MEDLINE | ID: covidwho-1726007

ABSTRACT

In January 2020, Chinese health agencies reported an outbreak of a novel coronavirus-2 (CoV-2) which can lead to severe acute respiratory syndrome (SARS). The virus, which belongs to the coronavirus family (SARS-CoV-2), was named coronavirus disease 2019 (COVID-19) and declared a pandemic by the World Health Organization (WHO). Full-length genome sequences of SARS-CoV-2 showed 79.6% sequence identity to SARS-CoV, with 96% identity to a bat coronavirus at the whole-genome level. COVID-19 has caused over 133,000 deaths and there are over 2 million total confirmed cases as of April 15th, 2020. Current treatment plans are still under investigation due to a lack of understanding of COVID-19. One potential mechanism to slow disease progression is the use of antiviral drugs to either block the entry of the virus or interfere with viral replication and maturation. Currently, antiviral drugs, including chloroquine/hydroxychloroquine, remdesivir, and lopinavir/ritonavir, have shown effective inhibition of SARS-CoV-2 in vitro. Due to the high dose needed and narrow therapeutic window, many patients are experiencing severe side effects with the above drugs. Hence, repurposing these drugs with a proper formulation is needed to improve the safety and efficacy for COVID-19 treatment. Extracellular vesicles (EVs) are a family of natural carriers in the human body. They play a critical role in cell-to-cell communications. EVs can be used as unique drug carriers to deliver protease inhibitors to treat COVID-19. EVs may provide targeted delivery of protease inhibitors, with fewer systemic side effects. More importantly, EVs are eligible for major aseptic processing and can be upscaled for mass production. Currently, the FDA is facilitating applications to treat COVID-19, which provides a very good chance to use EVs to contribute in this combat.


Subject(s)
Coronavirus Infections/drug therapy , Drug Repositioning , Extracellular Vesicles/chemistry , HIV Protease Inhibitors/administration & dosage , Pneumonia, Viral/drug therapy , Betacoronavirus/genetics , Betacoronavirus/metabolism , COVID-19 , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Drug Approval , Drug Delivery Systems , Humans , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , SARS-CoV-2
12.
Int J Mol Sci ; 21(8)2020 Apr 18.
Article in English | MEDLINE | ID: covidwho-1725799

ABSTRACT

COVID-19 has become a major global public health burden, currently causing a rapidly growing number of infections and significant morbidity and mortality around the world. Early detection with fast and sensitive assays and timely intervention are crucial for interrupting the spread of the COVID-19 virus (SARS-CoV-2). Using a mismatch-tolerant amplification technique, we developed a simple, rapid, sensitive and visual reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for SARS-CoV-2 detection based on its N gene. The assay has a high specificity and sensitivity, and robust reproducibility, and its results can be monitored using a real-time PCR machine or visualized via colorimetric change from red to yellow. The limit of detection (LOD) of the assay is 118.6 copies of SARS-CoV-2 RNA per 25 µL reaction. The reaction can be completed within 30 min for real-time fluorescence monitoring, or 40 min for visual detection when the template input is more than 200 copies per 25 µL reaction. To evaluate the viability of the assay, a comparison between the RT-LAMP and a commercial RT-qPCR assay was made using 56 clinical samples. The SARS-CoV-2 RT-LAMP assay showed perfect agreement in detection with the RT-qPCR assay. The newly-developed SARS-CoV-2 RT-LAMP assay is a simple and rapid method for COVID-19 surveillance.


Subject(s)
Betacoronavirus/isolation & purification , Clinical Laboratory Techniques/methods , Coronavirus Infections , Pandemics , Pneumonia, Viral , Betacoronavirus/genetics , Biological Assay , COVID-19 , COVID-19 Testing , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Humans , Nucleic Acid Amplification Techniques , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Reverse Transcriptase Polymerase Chain Reaction , Reverse Transcription , SARS-CoV-2 , Sensitivity and Specificity
13.
J Virol ; 94(12)2020 06 01.
Article in English | MEDLINE | ID: covidwho-1723543

ABSTRACT

The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that recently emerged in China is thought to have a bat origin, as its closest known relative (BatCoV RaTG13) was described previously in horseshoe bats. We analyzed the selective events that accompanied the divergence of SARS-CoV-2 from BatCoV RaTG13. To this end, we applied a population genetics-phylogenetics approach, which leverages within-population variation and divergence from an outgroup. Results indicated that most sites in the viral open reading frames (ORFs) evolved under conditions of strong to moderate purifying selection. The most highly constrained sequences corresponded to some nonstructural proteins (nsps) and to the M protein. Conversely, nsp1 and accessory ORFs, particularly ORF8, had a nonnegligible proportion of codons evolving under conditions of very weak purifying selection or close to selective neutrality. Overall, limited evidence of positive selection was detected. The 6 bona fide positively selected sites were located in the N protein, in ORF8, and in nsp1. A signal of positive selection was also detected in the receptor-binding motif (RBM) of the spike protein but most likely resulted from a recombination event that involved the BatCoV RaTG13 sequence. In line with previous data, we suggest that the common ancestor of SARS-CoV-2 and BatCoV RaTG13 encoded/encodes an RBM similar to that observed in SARS-CoV-2 itself and in some pangolin viruses. It is presently unknown whether the common ancestor still exists and, if so, which animals it infects. Our data, however, indicate that divergence of SARS-CoV-2 from BatCoV RaTG13 was accompanied by limited episodes of positive selection, suggesting that the common ancestor of the two viruses was poised for human infection.IMPORTANCE Coronaviruses are dangerous zoonotic pathogens; in the last 2 decades, three coronaviruses have crossed the species barrier and caused human epidemics. One of these is the recently emerged SARS-CoV-2. We investigated how, since its divergence from a closely related bat virus, natural selection shaped the genome of SARS-CoV-2. We found that distinct coding regions in the SARS-CoV-2 genome evolved under conditions of different degrees of constraint and are consequently more or less prone to tolerate amino acid substitutions. In practical terms, the level of constraint provides indications about which proteins/protein regions are better suited as possible targets for the development of antivirals or vaccines. We also detected limited signals of positive selection in three viral ORFs. However, we warn that, in the absence of knowledge about the chain of events that determined the human spillover, these signals should not be necessarily interpreted as evidence of an adaptation to our species.


Subject(s)
Betacoronavirus/genetics , Evolution, Molecular , Selection, Genetic , Amino Acid Sequence , Animals , Betacoronavirus/classification , COVID-19 , Chiroptera/virology , Coronavirus Infections/virology , Genome, Viral/genetics , Humans , Models, Molecular , Open Reading Frames/genetics , Pandemics , Phylogeny , Pneumonia, Viral/virology , SARS-CoV-2 , Viral Proteins/chemistry , Viral Proteins/genetics
14.
Chin Med J (Engl) ; 133(9): 1051-1056, 2020 May 05.
Article in English | MEDLINE | ID: covidwho-1722622

ABSTRACT

BACKGROUND: Medicines for the treatment of 2019-novel coronavirus (2019-nCoV) infections are urgently needed. However, drug screening using live 2019-nCoV requires high-level biosafety facilities, which imposes an obstacle for those institutions without such facilities or 2019-nCoV. This study aims to repurpose the clinically approved drugs for the treatment of coronavirus disease 2019 (COVID-19) in a 2019-nCoV-related coronavirus model. METHODS: A 2019-nCoV-related pangolin coronavirus GX_P2V/pangolin/2017/Guangxi was described. Whether GX_P2V uses angiotensin-converting enzyme 2 (ACE2) as the cell receptor was investigated by using small interfering RNA (siRNA)-mediated silencing of ACE2. The pangolin coronavirus model was used to identify drug candidates for treating 2019-nCoV infection. Two libraries of 2406 clinically approved drugs were screened for their ability to inhibit cytopathic effects on Vero E6 cells by GX_P2V infection. The anti-viral activities and anti-viral mechanisms of potential drugs were further investigated. Viral yields of RNAs and infectious particles were quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and plaque assay, respectively. RESULTS: The spike protein of coronavirus GX_P2V shares 92.2% amino acid identity with that of 2019-nCoV isolate Wuhan-hu-1, and uses ACE2 as the receptor for infection just like 2019-nCoV. Three drugs, including cepharanthine (CEP), selamectin, and mefloquine hydrochloride, exhibited complete inhibition of cytopathic effects in cell culture at 10 µmol/L. CEP demonstrated the most potent inhibition of GX_P2V infection, with a concentration for 50% of maximal effect [EC50] of 0.98 µmol/L. The viral RNA yield in cells treated with 10 µmol/L CEP was 15,393-fold lower than in cells without CEP treatment ([6.48 ±â€Š0.02] × 10vs. 1.00 ±â€Š0.12, t = 150.38, P < 0.001) at 72 h post-infection (p.i.). Plaque assays found no production of live viruses in media containing 10 µmol/L CEP at 48 h p.i. Furthermore, we found CEP had potent anti-viral activities against both viral entry (0.46 ±â€Š0.12, vs.1.00 ±â€Š0.37, t = 2.42, P < 0.05) and viral replication ([6.18 ±â€Š0.95] × 10vs. 1.00 ±â€Š0.43, t = 3.98, P < 0.05). CONCLUSIONS: Our pangolin coronavirus GX_P2V is a workable model for 2019-nCoV research. CEP, selamectin, and mefloquine hydrochloride are potential drugs for treating 2019-nCoV infection. Our results strongly suggest that CEP is a wide-spectrum inhibitor of pan-betacoronavirus, and further study of CEP for treatment of 2019-nCoV infection is warranted.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Betacoronavirus/genetics , COVID-19 , COVID-19 Testing , Cell Line , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Drug Approval , Humans , Pandemics , Pneumonia, Viral/diagnosis , RNA, Small Interfering/genetics , Real-Time Polymerase Chain Reaction , SARS-CoV-2 , Viral Load
15.
Chin Med J (Engl) ; 133(9): 1039-1043, 2020 May 05.
Article in English | MEDLINE | ID: covidwho-1722619

ABSTRACT

BACKGROUND: A patient's infectivity is determined by the presence of the virus in different body fluids, secretions, and excreta. The persistence and clearance of viral RNA from different specimens of patients with 2019 novel coronavirus disease (COVID-19) remain unclear. This study analyzed the clearance time and factors influencing 2019 novel coronavirus (2019-nCoV) RNA in different samples from patients with COVID-19, providing further evidence to improve the management of patients during convalescence. METHODS: The clinical data and laboratory test results of convalescent patients with COVID-19 who were admitted to from January 20, 2020 to February 10, 2020 were collected retrospectively. The reverse transcription polymerase chain reaction (RT-PCR) results for patients' oropharyngeal swab, stool, urine, and serum samples were collected and analyzed. Convalescent patients refer to recovered non-febrile patients without respiratory symptoms who had two successive (minimum 24 h sampling interval) negative RT-PCR results for viral RNA from oropharyngeal swabs. The effects of cluster of differentiation 4 (CD4)+ T lymphocytes, inflammatory indicators, and glucocorticoid treatment on viral nucleic acid clearance were analyzed. RESULTS: In the 292 confirmed cases, 66 patients recovered after treatment and were included in our study. In total, 28 (42.4%) women and 38 men (57.6%) with a median age of 44.0 (34.0-62.0) years were analyzed. After in-hospital treatment, patients' inflammatory indicators decreased with improved clinical condition. The median time from the onset of symptoms to first negative RT-PCR results for oropharyngeal swabs in convalescent patients was 9.5 (6.0-11.0) days. By February 10, 2020, 11 convalescent patients (16.7%) still tested positive for viral RNA from stool specimens and the other 55 patients' stool specimens were negative for 2019-nCoV following a median duration of 11.0 (9.0-16.0) days after symptom onset. Among these 55 patients, 43 had a longer duration until stool specimens were negative for viral RNA than for throat swabs, with a median delay of 2.0 (1.0-4.0) days. Results for only four (6.9%) urine samples were positive for viral nucleic acid out of 58 cases; viral RNA was still present in three patients' urine specimens after throat swabs were negative. Using a multiple linear regression model (F = 2.669, P = 0.044, and adjusted R = 0.122), the analysis showed that the CD4+ T lymphocyte count may help predict the duration of viral RNA detection in patients' stools (t = -2.699, P = 0.010). The duration of viral RNA detection from oropharyngeal swabs and fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (15 days vs. 8.0 days, respectively; t = 2.550, P = 0.013) and the duration of viral RNA detection in fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (20 days vs. 11 days, respectively; t = 4.631, P < 0.001). There was no statistically significant difference in inflammatory indicators between patients with positive fecal viral RNA test results and those with negative results (P > 0.05). CONCLUSIONS: In brief, as the clearance of viral RNA in patients' stools was delayed compared to that in oropharyngeal swabs, it is important to identify viral RNA in feces during convalescence. Because of the delayed clearance of viral RNA in the glucocorticoid treatment group, glucocorticoids are not recommended in the treatment of COVID-19, especially for mild disease. The duration of RNA detection may relate to host cell immunity.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/genetics , Pneumonia, Viral/genetics , RNA, Viral/genetics , Adult , Aged , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus Infections/rehabilitation , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/rehabilitation , Real-Time Polymerase Chain Reaction , Retrospective Studies , SARS-CoV-2
16.
Chin Med J (Engl) ; 133(9): 1015-1024, 2020 May 05.
Article in English | MEDLINE | ID: covidwho-1722617

ABSTRACT

BACKGROUND: Human infections with zoonotic coronaviruses (CoVs), including severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV, have raised great public health concern globally. Here, we report a novel bat-origin CoV causing severe and fatal pneumonia in humans. METHODS: We collected clinical data and bronchoalveolar lavage (BAL) specimens from five patients with severe pneumonia from Wuhan Jinyintan Hospital, Hubei province, China. Nucleic acids of the BAL were extracted and subjected to next-generation sequencing. Virus isolation was carried out, and maximum-likelihood phylogenetic trees were constructed. RESULTS: Five patients hospitalized from December 18 to December 29, 2019 presented with fever, cough, and dyspnea accompanied by complications of acute respiratory distress syndrome. Chest radiography revealed diffuse opacities and consolidation. One of these patients died. Sequence results revealed the presence of a previously unknown ß-CoV strain in all five patients, with 99.8% to 99.9% nucleotide identities among the isolates. These isolates showed 79.0% nucleotide identity with the sequence of SARS-CoV (GenBank NC_004718) and 51.8% identity with the sequence of MERS-CoV (GenBank NC_019843). The virus is phylogenetically closest to a bat SARS-like CoV (SL-ZC45, GenBank MG772933) with 87.6% to 87.7% nucleotide identity, but is in a separate clade. Moreover, these viruses have a single intact open reading frame gene 8, as a further indicator of bat-origin CoVs. However, the amino acid sequence of the tentative receptor-binding domain resembles that of SARS-CoV, indicating that these viruses might use the same receptor. CONCLUSION: A novel bat-borne CoV was identified that is associated with severe and fatal respiratory disease in humans.


Subject(s)
Betacoronavirus , Coronavirus Infections/virology , Pneumonia, Viral/virology , Adult , Aged , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/diagnostic imaging , Coronavirus Infections/therapy , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/diagnostic imaging , Pneumonia, Viral/therapy , SARS-CoV-2 , Tomography, X-Ray , Treatment Outcome
17.
Protein J ; 39(3): 198-216, 2020 06.
Article in English | MEDLINE | ID: covidwho-1718840

ABSTRACT

The devastating effects of the recent global pandemic (termed COVID-19 for "coronavirus disease 2019") caused by the severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) are paramount with new cases and deaths growing at an exponential rate. In order to provide a better understanding of SARS CoV-2, this article will review the proteins found in the SARS CoV-2 that caused this global pandemic.


Subject(s)
Betacoronavirus/chemistry , Betacoronavirus/physiology , Coronavirus Infections/virology , Pneumonia, Viral/virology , Viral Proteins/chemistry , Viral Proteins/metabolism , Amino Acid Sequence , Betacoronavirus/genetics , COVID-19 , Coronavirus Envelope Proteins , Coronavirus Infections/drug therapy , Coronavirus Infections/metabolism , Coronavirus Nucleocapsid Proteins , Drug Discovery/methods , Genome, Viral , Host-Pathogen Interactions/drug effects , Humans , Nucleocapsid Proteins/chemistry , Nucleocapsid Proteins/genetics , Nucleocapsid Proteins/metabolism , Pandemics , Phosphoproteins , Pneumonia, Viral/drug therapy , Pneumonia, Viral/metabolism , Polyproteins , Protein Interaction Maps/drug effects , SARS-CoV-2 , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/genetics , Viral Envelope Proteins/metabolism , Viral Matrix Proteins/chemistry , Viral Matrix Proteins/genetics , Viral Matrix Proteins/metabolism , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism , Viral Proteins/genetics , Viral Regulatory and Accessory Proteins/chemistry , Viral Regulatory and Accessory Proteins/genetics , Viral Regulatory and Accessory Proteins/metabolism , Viroporin Proteins
18.
Virology ; 568: 56-71, 2022 03.
Article in English | MEDLINE | ID: covidwho-1665518

ABSTRACT

SARS-CoV-2, the seventh coronavirus known to infect humans, can cause severe life-threatening respiratory pathologies. To better understand SARS-CoV-2 evolution, genome-wide analyses have been made, including the general characterization of its codons usage profile. Here we present a bioinformatic analysis of the evolution of SARS-CoV-2 codon usage over time using complete genomes collected since December 2019. Our results show that SARS-CoV-2 codon usage pattern is antagonistic to, and it is getting farther away from that of the human host. Further, a selection of deoptimized codons over time, which was accompanied by a decrease in both the codon adaptation index and the effective number of codons, was observed. All together, these findings suggest that SARS-CoV-2 could be evolving, at least from the perspective of the synonymous codon usage, to become less pathogenic.


Subject(s)
COVID-19/epidemiology , COVID-19/virology , Codon Usage , Codon , Evolution, Molecular , Pandemics , SARS-CoV-2/genetics , Betacoronavirus/classification , Betacoronavirus/genetics , Gene Expression Regulation, Viral , Genome, Viral , Genomics/methods , Humans , Open Reading Frames , Organ Specificity , Phylogeny
19.
Nat Med ; 26(6): 845-848, 2020 06.
Article in English | MEDLINE | ID: covidwho-1641979

ABSTRACT

We report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G (IgG). Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT-PCR results and for the identification of asymptomatic infections.


Subject(s)
Antibodies, Viral/blood , Antibody Formation/drug effects , Betacoronavirus/pathogenicity , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Adult , Aged , Antibody Formation/immunology , Antiviral Agents/therapeutic use , Betacoronavirus/genetics , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/immunology , Coronavirus Infections/virology , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Pandemics/prevention & control , Pneumonia, Viral/blood , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , SARS-CoV-2
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