2.2 Detection of SARS-CoV-2
200 µl sample supernatant was used for extraction of nucleic acids in GeneRotex 96 nucleic acid extraction instruments (TianLong Technology, Xi’an, China) in the Biosafety level 2 laboratory. Then RNA detection was done using qTower3G thermocycler (Analytikjena, Germany) by real-time RT-PCR methods. The primers and probes targeting the N and Orf1ab genes of SARS-CoV-2 were used (Zhu et al., 2020). The amplification was performed with the One Step PrimeScript™ RT-PCR kit (TaKaRa, Japan). The amplification condition was as follows: 42°C for 5 min, 95°C for 10 s, followed by 45 cycles of 95°C for 5 s and 58°C for 30 s.