Hamster Model for SARS-CoV-2 Infection

The hamster infection model of SARS-CoV-2 has been described before^{23 (link),24 (link)}. Female Syrian hamsters (Mesocricetus auratus) were purchased from Janvier Laboratories and kept per two in individually ventilated isolator cages (IsoCage N Bio-containment System, Tecniplast) at 21 °C, 55% humidity and 12:12 day/night cycles. Housing conditions and experimental procedures were approved by the ethics committee of animal experimentation of KU Leuven (license P065-2020). For infection, two groups of index female hamsters of 6-8 weeks old were anesthetized with ketamine/xylazine/atropine and inoculated intranasally with 50 µL containing 1×10⁴ TCID₅₀ of either SARS-CoV-2 WT virus or the 3CLpro^res virus(day 0). In the morning of day 1 post-infection (pi), each index hamster was co-housed with a contact (sentinel) hamster (non-infected hamsters) in one cage and the co-housing continued until the sacrifice day i.e. 3 days after start of exposure. On day 4 pi, animals were euthanized by intraperitoneal injection of 500 μL Dolethal (200 mg/mL sodium pentobarbital) and lungs were collected for further analysis. Two independent studies were performed each with a total of n = 12 per group.