Viremia and viral tissue distribution between the immunized-challenge group and the challenge group
To further evaluate the difference in viremia and distribution in ten tissues among different groups, serum samples from dpv 0, 7, 14, 21 and 28, dpi 3, 5, 7, 10, 14 and 21 and ten organ tissues were evaluated using real-time PCR. The RNA copy numbers of the serum samples in groups B1 and B2 reached their highest levels at 5 dpi and then gradually declined in these two groups (Fig. 5A, Fig. 5C). The viremia levels at every time point in groups A1 and A2 were significantly lower than those in groups B1 and B2, respectively (Fig. 5A, Fig. 5C). Furthermore, the viremia levels and the number of pigs with viremia in the homologous protection group (groups A1 and B1) were significantly lower than those in the heterologous protection group (groups A2 and B2) (Fig. 5A, Fig. 5C). The viral loads of ten tissues in groups A1 (except liver, stomach, intestine, brain and tonsil) and A2 (except tonsil and lymph nodes) were significantly lower than those in groups B1 and B2, respectively (Fig. 5A, Fig. 5C).