Table 2.

Detection of viral RNA in serum samples from challenged pigs by real-time RT-PCR (copies/μL).

No.	Days post-challenge
	0	1	3	7	10	15
A1	-	-	2.51 × 103	1.44 × 104	1.78 × 104	/
A2	-	-	1.69 × 104	8.50 × 103	2.47 × 104	/
A3	-	-	8.19 × 103	1.12 × 104	1.06 × 104	/
A4	-	-	1.15 × 104	2.56 × 104	1.33 × 104	/
A5	-	-	7.45 × 103	5.55 × 104	/	/
B1	-	-	2.22 × 105	6.60 × 104	7.05 × 105	/
B2	-	-	6.01 × 104	3.70 × 105	2.38 × 105	/
B3	-	-	1.94 × 105	1.44 × 105	5.23 × 105	6.70 × 105
B4	-	-	1.10 × 105	1.43 × 105	/	/
B5	-	-	1.19 × 105	9.35 × 104	3.46 × 105	/
C1	-	-	6.55 × 105	2.21 × 106	/	/
C2	-	-	7.56 × 105	9.57 × 105	1.49 × 106	/
C3	-	-	1.16 × 106	1.23 × 106	1.06 × 106	2.31 × 106
C4	-	-	4.24 × 105	1.13 × 106	2.63 × 106	/
C5	-	-	3.95 × 105	1.44 × 104	/	/
D1	-	-	3.81 × 104	1.35 × 104	7.79 × 105	5.40 × 105
D2	-	-	2.65 × 103	6.67 × 103	3.07 × 104	/
D3	-	-	3.98 × 103	8.05 × 105	2.21 × 104	5.53 × 105
E1	-	-	-	-	-	-
E2	-	-	-	-	-	-

Serum samples were collected prior to inoculation and at 1, 3, 7, 10 and 15 dpi and tested for viral RNA using the real-time RT-PCR as described previously (Zhao et al., 2008).