简介：AbstractInfection of humans by Powassan virus (POWV) occurs rarely but is potentially life-threatening. First isolated in Ontario, Canada in 1958, the presence of POWV has been confirmed in three countries: Canada, the USA, and Russia. Although a limited number of human cases has been reported thus far, the infection rate has shown signs of increasing during the 21st century. Interestingly, POWV and a genetically close variant, deer tick virus (DTV), are the only member of the tick-borne flaviviruses known to be endemic in North America and maintain in respective tick-host cycles. In this review, we briefly summarize current knowledge involving the epidemiology and etiology, pathogenesis and immunity, molecular evolution, and protein functions of POWV, aiming to increase our understanding of the virus and unlock the potential to control this lethal pathogen. These data may also provide tools to minimize the future threat of other emerging and re-emerging viruses.

简介：AbstractLike antibody evaluation, using an effective antigen-specific T-cell immunity assessment method in coronavirus disease 2019 (COVID-19) patients, survivors and vaccinees is crucial for understanding the immune persistence, prognosis assessment, and vaccine development for COVID-19. This study evaluated an empirically adjusted enzyme-linked immunospot assay for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T-cell immunity in 175 peripheral blood samples from COVID-19 convalescents and healthy individuals. Results of viral nucleic acid were used as the gold standard of infection confirmation. The SARS-CoV-2M peptide pool had higher sensitivity of 85% and specificity of 71% for the single peptide pool. For combined peptide pools, the parallel evaluation (at least one of the peptide pools is positive) of total peptide pools (S1&S2&M&N) had higher sensitivity (up to 93%), and the serial evaluation (all peptide pools are positive) of total peptide pools had higher specificity (up to 100%). The result of the serial evaluation was better than that of the parallel evaluation as a whole. The detection efficiency of M and N peptide pool serial evaluation appeared the highest, with a sensitivity of 80% and specificity of 93%. This T-cell immunity detection assay introduced in this report can achieve high operability and applicability. Therefore, it can be an effective SARS-CoV-2-specific cellular immune function evaluation method.

简介：AbstractA series of stringent non-pharmacological and pharmacological interventions were implemented to contain the pandemic but the pandemic continues. Moreover, vaccination breakthrough infection and reinfection in convalescent coronavirus disease 2019 (COVID-19) cases have been reported. Further, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants emerged with mutations in spike (S) gene, the target of most current vaccines. Importantly, the mutations exhibit a trend of immune escape from the vaccination. Herein the scientific question that if the vaccination drives genetic or antigenic drifts of SARS-CoV-2 remains elusive. We performed correlation analyses to uncover the impacts of wide vaccination on epidemiological characteristics of COVID-19. In addition, we investigated the evolutionary dynamics and genetic diversity of SARS-CoV-2 under immune pressure by utilizing the Bayesian phylodynamic inferences and the lineage entropy calculation respectively. We found that vaccination coverage was negatively related to the infections, severe cases, and deaths of COVID-19 respectively. With the increasing vaccination coverage, the lineage diversity of SARS-CoV-2 dampened, but the rapid mutation rates of the S gene were identified, and the vaccination could be one of the explanations for driving mutations in S gene. Moreover, new epidemics resurged in several countries with high vaccination coverage, questioning their current pandemic control strategies. Hence, integrated vaccination and non-pharmacological interventions are critical to control the pandemic. Furthermore, novel vaccine preparation should enhance its capabilities to curb both disease severity and infection possibility.

简介：AbstractMink has been identified as an animal with susceptibility to SARS-CoV-2 and also as the only animal with evidence to transmit the virus back to humans. Thus, the surveillance of viruses among high-density farmed minks has a significant meaning for the control of zoonotic emerging diseases in humans. Within anal swabs of minks that died of unknown causes in a mink farm, mink calicivirus (MCV) and mammalian orthoreovirus (MRV) were detected and simultaneously observed within MDCK cell culture from the sample of the same lethal mink. The parallel isolation was successfully performed by utilizing cell lines from different host sources with distinct viral sensitivities, i.e. Mv.1.Lu and Vero-E6 and the two viruses were independently separated. The prevalence of the virus among the minks and its genomic characteristics were investigated through deep sequencing technology. Phylogenetic analysis of the viral genome showed a close relationship of the newly isolated MCV-GCCDC8-2020 with MCV strains belonging to the genus Vesivirus, but with unique mutations derived from the major structural protein (VP1). The reovirus MRV-GCCDC9-2020 isolated from the same mink belongs to serotype 3 mammalian orthoreovirus and genome analysis showed a potential reassortment derived from reoviruses in different species. This study provides a beneficial reference on viral co-infection within disease investigation in farmed minks and raises the concern for the virus surveillance among the high-density fed animal farms.