Survival rates of pigs challenged with different doses of CSFV. Groups A, B and C (n = 5) were inoculated i.m. with 104, 105 and 106 TCID50 CSFV Shimen strain, respectively. Three non-inoculated pigs were housed in the same pen and served as in-contact animals. Two uninfected control pigs were housed in a separate pen.