Table 4.
Detection of virus in sera by isolation in porcine alveolar macrophages and by nested RT-PCR after the second challenge with PRRSV
|
Experiment |
Group |
Assay |
+7 (91 pi) |
+14 (98 pi) |
|
1 |
C1 + B |
Viral isolation |
2/2 |
2/2 |
| 3.2 ± 0.6 |
2.0 ± 0.0 |
|||
|
nRT-PCR |
2/2 |
2/2 |
||
|
A + A |
Viral isolation |
0/4 |
0/4 |
|
|
nRT-PCR |
4/4 |
1/4 |
||
|
A + B |
Viral isolation |
0/4 |
0/4 |
|
|
nRT-PCR |
4/4 |
0/4 |
||
| 2 |
C2 + A |
Viral isolation |
3/3 |
2/3 |
| 3.4 ± 0.9 |
2.2 ± 0.1 |
|||
|
nRT-PCR |
3/3 |
3/3 |
||
|
B + B |
Viral isolation |
0/4 |
0/4 |
|
|
nRT-PCR |
0/4* |
0/4 |
||
| B + A |
Viral isolation |
0/4 |
0/4 |
|
| nRT-PCR | 0/4* | 0/4 |
*Asterisks indicate statistical differences in the proportion of pigs found to be positive by RT-PCR in comparable groups of experiments 1 and 2 (i.e. homologous A + A versus homologous B + B).