Fig. 1: Competitive replication and transmission of Beta and wt-S614G in Syrian hamsters.
From: Enhanced fitness of SARS-CoV-2 variant of concern Alpha but not Beta
Six donor hamsters were each inoculated with a median tissue culture infectious dose (TCID50) of 104.25, determined by back titration and comprising a mixture of wt-S614G (orange) and Beta (green) at a 1:3.8 ratio, determined by quantitative PCR with reverse transcription (RT–qPCR). Donor, contact 1 and contact 2 hamsters were co-housed sequentially as shown in Extended Data Fig. 2a. Nasal washes were performed daily from 1–9 dpi and then every 2 days until 21 dpi. Pie charts show the ratio of variants detected in nasal washes at the indicated dpi. Pie chart sizes are proportional to the total number of viral genome copies per ml, as shown above or below each chart. Grey pies indicate values below the limit of detection (LOD; <103 viral genome copies per ml). Hamster silhouettes are coloured according to the dominant variant (>66%) detected in the last positive sample from each animal. Daggers indicate that the animal reached the humane endpoint; double daggers indicate a hamster that died during inhalation anaesthesia at 3 and 4 dpi. This required changes in the group composition in cage 6—the donor hamster was kept until 7 dpi and was co-housed in two different pairs: donor–contact 1a and donor–contact 1b.
