2.5 Virus isolation
The supernatant of Vero cells (African green monkey kidney cells) grown
into a single layer was discarded, washed once with PBS, and incubated
with 500 µL of patient serum for 2 h, and then discarded. Virus
maintenance solution (DMEM containing 2% fetal bovine serum) was added
and cultured at 37 °C under 5% CO2, and cytopathic
effects (CPEs) were observed daily. Tick suspensions that were positive
SFTSV by the nucleic acid test were filtered through a 0.22-µm bacterial
filter and were added to the Vero cells. Cells were collected, RNA was
extracted, reverse transcription was performed, and PCR detection was
performed to verify successful infection. The infected cells positive
for SFTSV were stored at −80 °C until use.