SARS-CoV-2 spike D614G variant exhibits highly efficient replication and transmission in hamsters

Abstract

SummarySARS-CoV-2 causes disease varying in severity from asymptomatic infections to severe respiratory distress and death in humans. The viral factors which determine transmissibility and pathogenicity are not yet clearly characterized. We used the hamster infection model to compare the replication ability and pathogenicity of five SARS-CoV-2 strains isolated from early cases originating in Wuhan, China, in February, and infected individuals returning from Europe and elsewhere in March 2020. The HK-13 and HK-95 isolates showed distinct pathogenicity in hamsters, with higher virus titers and more severe pathological changes in the lungs observed compared to other isolates. HK-95 contains a D614G substitution in the spike protein and demonstrated higher viral gene expression and transmission efficiency in hamsters. Intra-host diversity analysis revealed that further quasi species were generated during hamster infections, indicating that strain-specific adaptive mutants with advantages in replication and transmission will continue to arise and dominate subsequent waves of SARS-CoV-2 dissemination.

Viral MicroRNAs Encoded by Nucleocapsid Gene of SARS-CoV-2 Are Detected during Infection, and Targeting Metabolic Pathways in Host Cells

“…With further interpretation combined with RNA-seq data (#GSE161881 [20] and # GSE156005 [22]), we summarized that more host genes were up-regulated rather than down-regulated upon infection (Figure 2B). Since we hypothesized that v-miRNAs might directly interfere target gene expression (at a post-transcriptional level), we attempted to find the overlaps between the down-regulated host genes and predicted host targets that are enriched in metabolic processes.…”

“…Given the current lack of effective therapies and the spread of highly infective mutant SARS-CoV-2 strains worldwide [21], targeting these v-miRNAs and their interacting pathways should facilitate the identification of effective biomarkers and therapeutic strategies to counteract the course of disease progression in patients with critical COVID-19. [22,23]. The viral isolates were grown through Vero E6 cells (CRL-1586, ATCC) [22,23] in Dulbecco's modified Eagle's medium (DMEM) (Thermo Fisher Scientific, Waltham, MA, USA) supplemented with 10% fetal bovine serum (FBS) (Thermo Fisher Scientific, Waltham, MA, USA), 100 units/mL penicillin and 100 µg/mL streptomycin (1% P/S) (Thermo Fisher Scientific, Waltham, MA, USA).…”

“…[22,23]. The viral isolates were grown through Vero E6 cells (CRL-1586, ATCC) [22,23] in Dulbecco's modified Eagle's medium (DMEM) (Thermo Fisher Scientific, Waltham, MA, USA) supplemented with 10% fetal bovine serum (FBS) (Thermo Fisher Scientific, Waltham, MA, USA), 100 units/mL penicillin and 100 µg/mL streptomycin (1% P/S) (Thermo Fisher Scientific, Waltham, MA, USA). All experiments involving live SARS-CoV-2 were done in a Biosafety Level 3 (BSL-3) facility with strict adherence to the standard operating procedures.…”

Severe acute respiratory syndrome coronavirus 2 and influenza A virus co‐infection alters viral tropism and haematological composition in Syrian hamsters

“…We used a Syrian hamster model to study infection with SARS-CoV-2 and CA04, as well as in combination. The hamster represents a useful model for such a study, as it is susceptible to both viruses and displays clear clinical signs and pathology (Iwatsuki-Horimoto et al, 2018;Mok et al, 2020). Our data on weight change indicated that there was no synergistic or additive effect of co-infection.…”