Fig. 6: The protective efficacy of different vaccines against PCV2d challenge.

After the challenge, rectal temperature was measured daily, body weight was monitored at 0, 7, and 14 dpc, and viremia, viral shedding, and viral load of tissues were determined by detecting PCV2 DNA. Rectal temperature (a), average daily weight gain (b), viremia (c), fecal viral shedding (d), nasal viral shedding (e), and viral load of tissues (f) in distinct groups after the PCV2d challenge. Rectal temperatures are shown as means ± standard deviation (error bars), and above 40 °C (indicated by dashed line) are defined as fever. The average daily weight gain (ADWG) of individual animals is expressed as a color-coded symbol with midline and bars indicating means ± standard deviation. In (c–e), symbols represent the mean, the vertical bars indicate ± one standard deviation, and the numbers on the top of the error bar depict the percentage of positives in the PCV2d group at different time points. Data in (f) is expressed as per (b). Asterisks in (b, f) denote significant differences (*P < 0.05, ***P < 0.001) between the indicated groups, as determined by an unpaired two-tailed t-test with Welch’s correction as appropriate.