2.5 One-step growth curve experiment
To investigate the growth characteristics of YNG strain in vitro, monolayer Vero and PK15 cells seeded in 24-well plates were incubated with different strains (YNG and YNP, an isolation from pig farms where was close to this PRV-outbreaking goat farm) at multiplicity of infection (MOI) of 0.01 for 1 h. Both the cell debris and supernatant were collected after repeated freezing and thawing cycles, the viral copies and titers were determined via real-time PCR after the DNA extraction and TCID50 assay, respectively.