Figure 4From: Emergency vaccination alleviates highly pathogenic porcine reproductive and respiratory syndrome virus infection after contact exposureDetection of the virus load in sera of the pigs by SYBR Green real-time PCR after challenge. Serum samples were collected from living pigs in each group at different days post infection. Data were presented as the mean value of triplicate samples ± S.D. * means significant difference between Group 2 and 3(P<0.05).Back to article page