Journal of Medical Virology
○ Wiley
All preprints, ranked by how well they match Journal of Medical Virology's content profile, based on 140 papers previously published here. The average preprint has a 0.10% match score for this journal, so anything above that is already an above-average fit. Older preprints may already have been published elsewhere.
HIKMAT, H.; PY, J.; BOSCHI, C.; BUREL, E.; LE TARGA, L.; MILLION, M.; LESAGE, L.; MORAND, A.; LA SCOLA, B.; COLSON, P.
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Coronaviruses are known to evolve rapidly and be prone to new virus emergence. Human coronavirus-229E is one of the seven coronaviruses currently known to cause respiratory symptoms in humans. Genomic data are very scarce for this virus. Here, we implemented an in-house multiplex PCR strategy to amplify HCoV-229E genomes from nasopharyngeal samples diagnosed as positive for this virus RNA in Southeastern France. Then, next-generation sequencing was performed using Nanopore or Illumina technologies on Gridion or Novaseq 6000 instruments, respectively. HCoV-229E genomes were assembled and analyzed using MAFFT, MEGA, Itol, Nexstrain and Nextclade softwares. Thirty-one PCR primer pairs were designed to amplify overlapping fragments of the HCoV-229E genome. They allowed obtaining 123 genomes, which were classified in an emerging HCoV-229E lineage first reported in China, with two sublineages being delineated. Relatively to genome NC_002645.1 dating back to 1962, regarding nucleotide mutations, 1,167 substitutions, 72 insertions and 34 deletions were detected in viral genomes obatined here, while regarding amino acid mutations, 415 susbstitutions, 39 deletions and 14 amino acid insertions were detected. The genes with the greatest diversity were S (that encodes the spike protein) then Nsp3. Signature mutations were identified for the two sublineages. In summary, we almost doubled the set of HCoV-229E genomes available worldwide and provided the first genomes from France. Further studies are needed to strengthen the knowledge about the phylogenomics and evolutionary dynamics of this neglected respiratory virus, and about their specificities, which may also purvey clues to contribute improving knowledge for all other human coronaviruses.
Kumar, A.; Asghar, A.; Singh, H. N.; Faiq, M. A.; Kumar, S.; Narayan, R. K.; Kumar, G.; Dwivedi, P.; Sahni, C.; Jha, R. K.; Kulandhasamy, M.; Prasoon, P.; Sesham, K.; Kant, K.; Pandey, S. N.
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BackgroundA newly emerged SARS-CoV-2 variant B.1.1.529 has worried the health policy makers worldwide due to the presence of a large number of mutations in its genomic sequence, especially in the spike protein region. World Health Organization (WHO) has designated it as a global variant of concern (VOC) and has named as Omicron. A surge in new COVID-19 cases have been reported from certain geographical locations, primarily in South Africa (SA) following the emergence of Omicron. Materials and methodsWe performed an in silico analysis of the complete genomic sequences of Omicron available on GISAID (until 2021-12-10) to predict the functional impact of the mutations present in this variant on virus-host interactions in terms of viral transmissibility, virulence/lethality, and immune escape. The mutations present at the receptor binding domain (RBD) of the variants were assessed using an open analysis pipeline which integrates a yeast-display platform with deep mutational scanning. Further, we performed a correlation analysis of the relative proportion of the genomic sequences of specific SARS-CoV-2 variants (in the period of 01 Oct-10th Dec, 2021) with the current epidemiological data (new COVID-19 cases and deaths) from SA to understand whether the Omicron has an epidemiological advantage over existing variants. ResultsCompared to the current list of global VOCs/VOIs (as per WHO) Omicron bears more sequence variation, specifically in the spike protein and host receptor-binding motif (RBM). Omicron showed the closest nucleotide and protein sequence homology with Alpha variant for the complete sequence as well as for RBM. The mutations were found primarily condensed in spike region (28-48) of the virus. Further, the mutational analysis showed enrichment for the mutations decreasing ACE2-binding affinity and RBD protein expression, in contrast, increasing the propensity of immune escape. An inverse correlation of Omicron with Delta variant was noted (r=-0.99, p< .001, 95% CI: -0.99 to - 0.97) in the sequences reported from SA post-emergence of the new variant, later showing a decrease. There has been a steep rise in the new COVID-19 cases in parallel with increase in the proportion of Omicron since the first case (74-100%), on the contrary, the incidences of new deaths have not been increased (r=-0.04, p>0.05, 95% CI =-0.52 to 0.58). ConclusionsOmicron may have greater immune escape ability than the existing VOCs/VOIs. However, there are no clear indications coming out from the predictive mutational analysis that the Omicron may have higher virulence/lethality than other variants, including Delta. The higher ability for immune escape may be a likely reason for the recent surge in Omicron cases in SA. HighlightsO_LIHigher immune escape ability than the existing VOCs/VOIs C_LIO_LINo clear indications of increased affinity for ACE2 binding C_LIO_LIDriving a new COVID-19 wave in South Africa C_LIO_LIOutcompeting Delta variant C_LIO_LICurrently, no clear evidence for increased virulence/lethality C_LI
Wu, A.; Niu, P.; Wang, L.; Zhou, H.; Zhao, X.; Wang, W.; Wang, J.; Ji, C.; Ding, X.; Wang, X.; Lu, R.; Gold, S.; Aliyari, S.; Zhang, S.; Vikram, E.; Zou, A.; Lenh, E.; Chen, J.; Ye, F.; Han, N.; Peng, Y.; Guo, H.; Wu, G.; Jiang, T.; Tan, W.; Cheng, G.
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BackgroundThe 2019 novel coronavirus (2019-nCoV or SARS-CoV-2) has spread more rapidly than any other betacoronavirus including SARS-CoV and MERS-CoV. However, the mechanisms responsible for infection and molecular evolution of this virus remained unclear. MethodsWe collected and analyzed 120 genomic sequences of 2019-nCoV including 11 novel genomes from patients in China. Through comprehensive analysis of the available genome sequences of 2019-nCoV strains, we have tracked multiple inheritable SNPs and determined the evolution of 2019-nCoV relative to other coronaviruses. ResultsSystematic analysis of 120 genomic sequences of 2019-nCoV revealed co-circulation of two genetic subgroups with distinct SNPs markers, which can be used to trace the 2019-nCoV spreading pathways to different regions and countries. Although 2019-nCoV, human and bat SARS-CoV share high homologous in overall genome structures, they evolved into two distinct groups with different receptor entry specificities through potential recombination in the receptor binding regions. In addition, 2019-nCoV has a unique four amino acid insertion between S1 and S2 domains of the spike protein, which created a potential furin or TMPRSS2 cleavage site. ConclusionsOur studies provided comprehensive insights into the evolution and spread of the 2019-nCoV. Our results provided evidence suggesting that 2019-nCoV may increase its infectivity through the receptor binding domain recombination and a cleavage site insertion. One Sentence SummaryNovel 2019-nCoV sequences revealed the evolution and specificity of betacoronavirus with possible mechanisms of enhanced infectivity.
huang, l.; li, q.; Sayed, S. Z. A.; Mohammad, N.; chen, b.; Iftikhar, M. A.; Xie, L.; Hu, J.; chen, h.
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QuestionIs ultra-short-wave diathermy (USWD) safe and effective in coronavirus disease 2019 (COVID-19) ? DesignSingle-centre, evaluator-blinded, two-arm, parallel design, randomized controlled clinical trial. ParticipantsModerate and severe COVID-19 patients with acute respiratory syndrome. InterventionUSWD for 10 minutes twice daily for 12 consecutive days along with standard medical treatment (USWD group, n = 25), versus standard medical treatment alone (control group, n = 25). Outcome measuresThe primary outcomes were the duration of recovery and negative conversion rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on days 7, 14, 21, and 28. Secondary outcomes included clinical status (seven-category ordinal and systemic inflammatory response syndrome (SIRS) scores), computed tomography (CT), routine blood tests, and adverse events. ResultsTime to clinical recovery (USWD 36.84{+/-}9.93 vs. control 43.56{+/-}12.15, P = 0.037) was significantly shortened with a between-group difference of 6.72 days. Clinical status was improved with significant between-group differences on day 28 (SIRS, P = 0.011; seven-category scale, P = 0.003). The rate of RNA negative conversion at days 7 (P = 0.066), 14 (P = 0.239), 21 (P = 0.269), and 28 (P = 0.490) was statistically insignificant. Moreover, insignificant differences were observed in the artificial intelligence-assisted CT analysis. No treatment-associated adverse events or worsening of pulmonary fibrosis were observed. ConclusionUSWD, as adjunctive therapy, shortened the recovery course and improved clinical status of patients with COVID-19 without aggravating pulmonary fibrosis. the findings are limited due to the small sample size and early termination. RegistrationChiCTR2000029972
Tan, L.; Kang, X.; Zhang, B.; Zheng, S.; Liu, B.; Yu, T.; Yang, F.; Wang, Q.; Miao, H.
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Prolonged viral shedding is associated with severe status and poor prognosis of COVID-19 patients. Unexpectedly, here we report a non-severe patient with the longest duration of viral shedding. According to the investigation on the clinical and epidemiological information of this case, we concluded that this type of virus might have a low toxicity and transmissibility, but have a prolonged infective ability and was hardly to be eliminated in the body with regular therapy. However, infusion of plasma from recovered patients showed high efficiency in elimination of this virus. Our findings might shed light on the management of COVID-19.
Yuan, J.; Kou, S.; Liang, Y.; Zeng, J.; Pan, Y.; Liu, L.
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Here we report the clinical features of 25 discharged patients with COVID-19 recovery. Our analysis indicated that there was a significant inverse correlation existed between serum D-Dimer level and the duration of antiviral treatment, while lymphocyte concentration significantly positively correlated with the duration of virus reversal.
Contelli Klein, R.; Fabres Klein, M. H.; Barbosa, L. G.; Knnup, L. V. G.; Venancio, L. P. R.; Berlink Lima, J.; Araujo-Santos, T.
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IntroductionMolecular diagnosis of SARS-CoV-2 is a huge challenge to many countries around the world. The cost of tests to check infected people is inaccessible since specialized teams and equipment are not disposable in remote locations. Herein, we compared the fitness of two primers sets to the SARS-CoV-2 N gene in the molecular diagnosis of COVID-19. Materials and MethodsThe 1029 patient samples were tested to presense/abscence molecular test using in house US CDC protocol. We compared the fitness of two primers sets to two different regions of N gene targets. ResultsBoth targets, N1 and N2 displayed similar fitness during testing with no differences between Ct or measurable viral genome copies. In addition, we verified security ranges Cts related to positive diagnostic with Ct above 35 value failuring in 66,6% after retesting of samples. Main conclusionOur data suggest that it is secure to use just one primer set to the N gene to identify SARS-CoV-2 in samples and the labs should be careful to set positive samples in high Ct values using high cutoffs.
Xu, Y.
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In December 2019, a cluster of acute respiratory illness, now known as SARS-CoV-2 pneumonia, occurred in Wuhan, China. World Health Organization (WHO) declared the rapidly spreading coronavirus outbreak a pandemic on March 11, 2020, acknowledging what has seemed clear for some time -- the virus will likely spread to all countries on the globe. As of February 11, 2020, the Chinese Center for Disease Control and Prevention (China CDC) has officially reported that there are 2.0% (889) asymptomatic cases, 2.3% (1,023) death cases, and 80.9% mild cases among 44,672 confirmed cases. 51.4% (22,981) were male and 48.6% (21,691) were female. Lymphopenia, in particular T lymphopenia, was common among patients with SARS-COV-2 in the observation. A notable drop in CD4 and CD8 lymphocyte counts occurred early in the course of the syndrome and was associated with adverse outcomes. The appearing a phenomenon of lymphocyte depletion (PLD) suggested severe adverse outcomes. The outcome observed: 60% had discharged and 20% had die.
Ou, X.; Yang, Z.; Zhu, D.; Mao, S.; Wang, M.; Jia, R.; Chen, S.; Liu, M.; Yang, Q.; Wu, Y.; Zhao, X.; Zhang, S.; Huang, J.; Gao, Q.; Liu, Y.; Zhang, L.; Peopplenbosch, M.; Pan, Q.; Cheng, A.-c.
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During the COVID-19 pandemic, precisely tracing the route of the SARS-CoV-2 transmission in human population remains challenging. Because this RNA virus can mutate massively without a specifically tracing maker. Herein, using a geographic stratified genome-wide association study (GWAS) of 2599 full-genome sequences, we identified that two SNPs (i.e., 1059.C>T and 25563.G>T) of linkage disequilibrium were presented in approximately half of North America SARS-CoV-2 population (p = 2.44 x 10-212 and p = 2.98 x 10-261), resulting two missense mutations (i.e., Thr 265 Ile and Gln 57 His) in ORF1ab and ORF3a, respectively. Interestingly, these two SNPs exclusively occurred in the North America dominated clade 1, accumulated during mid to late March, 2020. We did not find any of these two SNPs by retrospectively tracing the two SNPs in bat and pangolin related SARS-CoV-2 and human SARS-CoV-2 from the first epicenter Wuhan or other regions of China mainland. This suggested that the SARS-CoV-2 population of Chinese mainland were different from the prevalent strains of North America. Time-dependently, we found that these two SNPs first occurred in Europe SARS-CoV-2 (26-Feb-2020) which was 3 days early than the occurring date of North America isolates and 17 days early for Asia isolates (Taiwan China dominated). Collectively, this population genetic analysis highlights a well-confidential transmission route of the North America isolates and the two SNPs we newly identified are possibly novel diagnosable or druggable targets for surveillance and treatment.
Cabral, G. B.; Ahagon, C. M.; Lopez-Lopes, G. I. S.; Hussein, I. M.; Guimaraes, P. M.; Cilli, A.; Silva, V. O.; Timenetsky, M. d. C. S.; Alves, I. d. J.; Bombonatte, A. G.; dos Santos, F. C. P.; Brigido, L. F. d. M.
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SARS-CoV-2 variants, along with vaccination, mark the second year of the pandemic. The spike region is a focal point in COVID-19 pathogenesis, with different amino acid changes potentially modulating vaccine response and some being part of variant signatures. NGS is the standard tool to sequence the virus but limitations of different sources hinders expansion of genomic surveillance in many places. To improve surveillance capability we developed a Sanger based sequencing protocol to obtain coverage of most (>95%) spike gene. Eleven nasopharyngeal swabs collections had RNA extracted for real time PCR diagnosis and leftover RNA had up to 3785 bp sequenced at an ABI3500 using dye termination chemistry of nested PCR products of two reactions of one-step RT-PCR. P1 amino acid mutations signatures were present in 18% (2/11), with 82% (9/11) with three or more additional amino acid changes (GISAID CoVsurver list). Most sequences (86%, 6/7) from 2021 have the E484K, whereas the mutation was not present in samples collected in 2020 (0/4, p=0.015).The swiftness that favorable mutations to the virus may prevail and their potential impact in vaccines and other current interventions need broader surveillance and more public health attention.
Chang, H.; Hung, T. H.; Li, B.; Kong, B. L. H.; Wang, Y.; Tsai, M.-s.; Deng, D.; Cui, Z.
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Human mpox, formerly known as monkeypox, has twice been declared a Public Health Emergency of International Concern (PHEIC) by the World Health Organization, in 2022 and 2024. Despite this, global access to rapid, reliable diagnostics remains limited, hindering outbreak control and equitable clinical response. To address this gap, we developed and validated a rapid direct real-time PCR assay capable of detecting and differentiating Clade I and Clade II monkeypox virus (MPXV) directly from clinical samples. We designed a new pan-specific B15L assay to complement the published F3L assay and introduced the first clade-specific assay targeting the B1R gene of Clade I MPXV. In silico validation showed that both B15L and F3L assays detected all available MPXV genomes with 100% sensitivity, while B1R selectively detected only Clade I genomes with 100% specificity. Cross-reactivity screening against 40 high-priority non-target organisms revealed minimal risk of false positives. We confirmed analytical sensitivity of 2 copies per reaction for all assays in vitro, with clade-specific B1R showing 100% specificity. When adapted into a lyophilised direct PCR format for near-point-of-care use, the assay demonstrated detection down to 1 copy per reaction for pan-specific targets and 2 copies for clade-specific detection in spiked clinical samples. This direct PCR assay delivers accurate results in under one hour without requiring nucleic acid extraction. Our combined genomic, laboratory, and clinical validations demonstrate exceptional sensitivity and specificity, positioning this assay as a highly promising tool in emergency mpox diagnostics and a potential model for future outbreak-responsive testing platforms.
Naveca, F. G.; Nascimento, V. A.; Nascimento, F.; Ogrzewalska, M.; Pauvolid-Correa, A.; Araujo, M. F.; Arantes, I.; Batista, E. L. R.; Magalhaes, A. L. l.; Vinhal, F.; Mattos, T. P.; Riediger, I.; Debur, M. d. C.; Grinsztejn, B.; Veloso, V. G.; Brasil, P.; Rodrigues, R. R.; Rovaris, D. B.; Fernandes, S. B.; Fernandes, C.; Santos, J. H. A.; Abdalla, L. F.; Costa-Filho, R.; Silva, M.; Souza, V.; Costa, g. A.; Mejia, M.; Brandao, M. J.; Goncalves, L. F.; Silva, G. A.; Jesus, M. S. d.; Pessoa, K.; Corado, A. d. L. G.; Duarte, D. C. G.; Machado, A. B.; Zukeram, K. d. A.; Valente, N.; Lopes, R. S.;
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The rapid spread of the SARS-CoV-2 Variant of Concern (VOC) Gamma during late 2020 and early 2021 in Brazilian settings with high seroprevalence raised some concern about the potential role of reinfections in driving the epidemic. Very few cases of reinfection associated with the VOC Gamma, however, have been reported. Here we describe 25 cases of SARS-CoV-2 reinfection confirmed by real-time RT-PCR twice within months apart in Brazil. SARS-CoV-2 genomic analysis confirmed that individuals were primo-infected between March and December 2020 with distinct viral lineages, including B.1.1, B.1.1.28, B.1.1.33, B.1.195 and P.2, and then reinfected with the VOC Gamma between 3 to 12 months after primo-infection. The overall mean cycle threshold (Ct) value of the first (25.7) and second (24.5) episodes were roughly similar for the whole group and 14 individuals displayed mean Ct values < 25.0 at reinfection. Sera of 14 patients tested by plaque reduction neutralization test after reinfection displayed detectable neutralizing antibodies against Gamma and other SARS-CoV-2 variants (B.1.33, B.1.1.28 and Delta). All individuals have milder or no symptoms after reinfection and none required hospitalization. The present study demonstrates that the VOC Gamma was associated with reinfections during the second Brazilian epidemic wave in 2021 and raised concern about the potential infectiousness of reinfected subjects. Although individuals here analyzed failed to mount a long-term sterilizing immunity, they developed a high anti-Gamma neutralizing antibody response after reinfection that may provide some protection against severe disease.
Gupta, V.; Haider, S.; Verma, M.; Ponnusamy, K.; Malik, M. Z.; Singhvi, N.; Verma, H.; Kumar, R.; Sood, U.; Hira, P.; Satija, S.; Lal, R.
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SARS-CoV-2 pandemic resulted in 92 million cases in a span of one year. The study focuses on understanding population specific variations attributing its high rate of infections in specific geographical regions particularly in USA. Rigorous phylogenomic network analysis of complete SARS-CoV-2 genomes (245) inferred five central clades named a (ancestral), b, c, d and e (subtype e1 & e2). The clade d & e2 were found exclusively comprising of USA. Clades were distinguished by 10 co-mutational combinations in Nsp3, ORF8, Nsp13, S, Nsp12, Nsp2 and Nsp6. Our analysis revealed that only 67.46% of SNP mutations were at amino acid level. T1103P mutation in Nsp3 was predicted to increase protein stability in 238 strains except 6 strains which were marked as ancestral type; whereas co-mutation (P409L & Y446C) in Nsp13 were found in 64 genomes from USA highlighting its 100% co-occurrence. Docking highlighted mutation (D614G) caused reduction in binding of Spike proteins with ACE2, but it also showed better interaction with TMPRSS2 receptor contributing to high transmissibility among USA strains. We also found host proteins, MYO5A, MYO5B, MYO5C had maximum interaction with viral proteins (N, S, M). Thus, blocking the internalization pathway by inhibiting MYO5 proteins which could be an effective target for COVID-19 treatment. The functional annotations of the HPI network were found to be closely associated with hypoxia and thrombotic conditions confirming the vulnerability and severity of infection. We also screened CpG islands in Nsp1 & N conferring ability of SARS-CoV-2 to enter and trigger ZAP activity inside host cell. ImportanceIn the current study we presented a global view of mutational pattern observed in SARS-CoV-2 virus transmission. This provided a who-infect-whom geographical model since the early pandemic. This is hitherto the most comprehensive comparative genomics analysis of full-length genomes for co-mutations at different geographical regions specially in USA strains. Compositional structural biology results suggested that mutations have balance of contrary forces effect on pathogenicity suggesting only few mutations to effective at translation level but not all. Novel HPI analysis and CpG predictions elucidates the proof of concept of hypoxia and thrombotic conditions in several patients. Thus, the current study focuses the understanding of population specific variations attributing high rate of SARS-CoV-2 infections in specific geographical regions which may eventually be vital for the most severely affected countries and regions for sharp development of custom-made vindication strategies.
He, X.; Zhang, L.; Ran, Q.; Xiong, A.; Wang, J.; Wu, D.; Chen, F.; Li, G.
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The 2019-nCoV is reported to share the same entry (ACE2) as SARS-CoV according to the updated findings. Analyzing the distribution and expression level of the route of coronavirus may help reveal underlying mechanisms of viral susceptibility and post-infection modulation. In this study, we found that the expression of ACE2 in healthy populations and patients with underlying diseases was not significantly different, suggesting relatively similar susceptibility. Besides, based on the expression of ACE2 in smoking individuals, we inferred that long-term smoking might be a risk factor for 2019-nCoV. Analyzing the ACE2 in SARS-CoV infected cells suggested that ACE2 was more than just a receptor but also participated in post-infection regulation, including immune response, cytokine secretion, and viral genome replication. Moreover, we also constructed Protein-protein interaction (PPI) networks and identified hub genes in viral activity and cytokine secretion. Our findings may explain the clinical symptoms so far and help clinicians and researchers understand the pathogenesis and design therapeutic strategies for 2019-nCoV.
Huang, J.-M.; Jan, S. S.; Wei, X.; Wan, Y.; Ouyang, S.
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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.
Melquiades, T.; Martins, R.; Miura, C.; Oliveira, M. V.; Cassiano, M.; Rodrigues, T.; Veras, F.; Souza, J. F.; Gomes, R.; Almeida, G.; Melo, S. R.; Conde, G.; Dias, M.; Capato, F.; Silva, M. L.; Barros, V.; Carenzi, L.; Zamboni, D. S.; Macedo, D.; Tamashiro, E.; Anselmo-Lima, W.; Valera, F. C.; Arruda, E.
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In the present study, we show that SARS-CoV-2 can infect palatine tonsils and adenoids in children without symptoms of COVID-19, with no history of recent upper airway infection. We studied 48 children undergoing tonsillectomy due to snoring/OSA or recurrent tonsillitis between October 2020 and September 2021. Briefly, nasal cytobrush (NC), nasal wash (NW) and tonsillar tissue fragments obtained at surgery were tested by RT-PCR, immunohistochemistry (IHC), flow cytometry and neutralization assay. We detected the presence of SARS-CoV-2 in at least one specimen tested in 25% of patients (20% in palatine tonsils and 16.27% in adenoids, 10.41% of NC and 6.25% of NW). Importantly, in 2 of the children there was evidence of laboratory-confirmed acute infection 2 and 5 months before surgery. IHC revealed the presence of SARS-CoV-2 nucleoprotein in epithelial surface and in lymphoid cells in both extrafollicular and follicular regions, in adenoids and palatine tonsils. Flow cytometry showed that CD20+ B lymphocytes were the most infected phenotypes by SARS-CoV-2 NP, followed by CD4+ and CD8+ T lymphocytes, and CD14+ macrophages and dendritic cells. Additionally, IF indicated that SARS-CoV-2-infected tonsillar tissues had increased expression of ACE2 and TMPRSS2. NGS sequencing demonstrated the presence of different SARS CoV-2 variants in tonsils from different tissues. SARS-CoV-2 antigen detection was not restricted to tonsils, but was also detected in nasal cells from the olfactory region. In conclusion, palatine tonsils and adenoids are sites of prolonged infection by SARS-CoV-2 in children, even without COVID-19 symptoms.
Imai, K.; Ikeno, R.; Tanaka, H.; Takada, N.
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The emergence of SARS-CoV-2 Delta variants has escalated COVID-19 cases globally due to their high transmissibility. Since saliva is crucial for SARS-CoV-2 transmission, we hypothesized that a higher viral load of Delta variants in saliva than their parental wild-type strains contributed to the high transmissibility in the first place. However, studies have not reported this particular comparison done with viral copy numbers. Twenty-two genetically confirmed -positive saliva samples for wild-type strain and 32 Delta variants were statistically compared for viral copy number per milliliter determined by real-time qPCR combined with synthesized viral RNA and Poissons null distribution equation between the groups of wild and variant strains and between whole saliva and centrifugal supernatant in each group. We found that the copy number of the Delta variants was 15.1 times higher than wild-type strains of the whole saliva. In addition, the viral load of both strains in the whole saliva was higher than the pertinent supernatant, indicating that most viruses in the whole saliva are associated with host cells. Meanwhile, more than a million virions per milliliter of the viral load of the variants in the supernatants were 4.0 times higher but not significant than wild-type strains. Humanity must share our findings; the simple but concrete note that Delta variant viral load is abundant in the saliva is critical for preventing the spread of infection.
Ghazimoradi, M. H.; Daryani, M.; Gharshasbi, M.; Zolghadr, E.; Khalafizadeh, A.; Babashah, S.
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BackgroundSARS-Cov-2 is a new virus that caused an epidemic disease, COVID-19. According to the world health organization, detecting the patients/carriers is by the far the most important action to prevent the pandemic. Recently, the loop-mediated isothermal amplification (LAMP) technique has become more popular due to the easy handling of a one-step kit used for the detection of many diseases than RT-PCR-based techniques. methodsHerein, we used the RT-LAMP technique so as to detect COVID-19. To this end, 40 paired-samples of patients and healthy people had been collected and tested by RT-PCR for N and E genes of SARS-CoV-2. The RT-LAMP test has been performed on samples for the RdRp gene. The sensitivity and specificity of tests have been determined. ResultsThe testing results are consistent with the conventional RT-qPCR. Additionally, we also showed that a one-step process without RNA extraction is feasible to achieve RNA amplification directly from a sample. ConclusionWe confirmed that RT-LAMP is a rapid, simple, and sensitive method that can be used as a large-screening method, particularly in regional hospitals with limited access to high-technologies.
Sarkar, R.; Banerjee, D. A.; Dutta, S.; Chawla-Sarkar, D. M.
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SARS-CoV-2 strains with both high transmissibility and potential to cause asymptomatic infection is expected to gain selective advantage over other circulating strains having either high transmissibility or ability to trigger asymptomatic infection. The D614G mutation in spike glycoprotein, the characteristic mutation A2a clade, has been associated with high transmissibility, whereas the A3 clade specific mutation L37F in NSP6 protein has been linked with asymptomatic infection. In this study, we performed a comprehensive mutational analysis of 3,77,129 SARS-CoV-2 genomes collected during January, 2020 to December, 2020 from all across the world for the presence of D614G and L37F mutations. Out of 3,77,129 SARS-CoV-2 strains analysed, 14, 598 (3.87%) were found to harbour both the D614G and L37F mutations. Majority of these double mutant SARS-CoV-2 strains were identified in Europe (11097) followed by North America (1915), Asia (980), Oceania (242), Africa (219), and South America (145). Geographical root surveillance revealed their first emergence during February-March in all the six continents. Temporal prevalence analysis from February, 2020 to December, 2020 showed a gradual upsurge in their frequencies worldwide, which strongly demonstrated the adaptive selection of these double mutants. Evolutionary analysis depicted that these double mutants emerged as a new clade in the dendrogram (named as A2a/3), and were sub-divided into four distinct clusters (Cluster I, II, III and IV) according to different sets of coexisting mutations. The frequency distribution pattern showed the global predominance of cluster III (41.42%), followed by cluster IV (23.31%), cluster II (21.02%) and cluster I (14.25%). Overall, our study highlighted the emergence of a unique phylogenetic clade encompassing the double-mutant SARS-CoV-2 strains which may provide a fitness advantage during course of virus evolution.
Chen, Z.-w.; Li, Z.; Li, H.; Ren, H.; Hu, P.
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BackgroundSince it was firstly discovered in China, the SARS-CoV-2 epidemic has caused a substantial health emergency and economic stress in the world. However, the global genetic diversity and transmissions are still unclear. Methods3050 SARS-CoV-2 genome sequences were retrieved from GIASID database. After aligned by MAFFT, the mutation patterns were identified by phylogenetic tree analysis. ResultsWe detected 17 high frequency (>6%) mutations in the 3050 sequences. Based on these mutations, we classed the SARS-CoV-2 into four main groups and 10 subgroups. We found that group A was mainly presented in Asia, group B was primarily detected in North America, group C was prevailingly appeared in Asia and Oceania and group D was principally emerged in Europe and Africa. Additionally, the distribution of these groups was different in age, but was similar in gender. Group A, group B1 and group C2 were declined over time, inversely, group B2, group C3 and group D were rising. At last, we found two apparent expansion stages (late Jan-2020 and late Feb-2020 to early Mar-2020, respectively). Notably, most of groups are quickly expanding, especially group D. ConclusionsWe classed the SARS-CoV-2 into four main groups and 10 subgroups based on different mutation patterns at first time. The distribution of the 10 subgroups was different in geography, time and age, but not in gender. Most of groups are rapidly expanding, especially group D. Therefore, we should attach importance to these genetic diversity patterns of SARS-CoV-2 and take more targeted measures to constrain its spread.