Clinical score values and body temperature from CSF SM strain experimentally infected pigs. The clinical score of the infected pigs showed a continued increasing trend from day 0 to day 8 post infection, which was found to correlate well with the virus load ratio. The noninfected control kept at a score of 0. The body temperature began to increase on the 2th day after infection. Then the temperature were kept around continued 41.5°C for 1 to 1.5 days, then began to decline at day 4 to 5 post infection. However, it showed irregular changes from day 6 to day 8 near to death. While the body temperature of the control group maintained at the normal level of 39.5°C.