Table 3 Analytical sensitivity of SVV real-time RT-PCR (rRT-PCR) and SVV RT-insulated isothermal PCR (RT-iiPCR) using viral RNA from the serially diluted two SVV isolates
Virus strain | Dilution | Theoretical titer (TCID50/ml) | SVV RT-iiPCR | SVV rRT-PCR (CT) | ||||
|---|---|---|---|---|---|---|---|---|
Result 1 | Result 2 | Result 3 | Result 1 | Result 2 | Result 3 | |||
US historical SVV isolate SVV-1 (ATCC-PTA-5342) | 10−4 | 3000 | + | + | + | 28.4 | 27.8 | 27.5 |
10−5 | 300 | + | + | + | 31.7 | 30.8 | 30.4 | |
10−6 | 30 | + | + | + | 34.1 | 33.8 | 35.0 | |
10−7 | 3 | ? | – | ? | 36.8 | 37.3 | 36.7 | |
10−8 | 0.3 | – | – | – | Neg | Neg | Neg | |
10−9 | 0.03 | – | – | – | Neg | Neg | Neg | |
10−10 | 0.003 | – | – | – | Neg | Neg | Neg | |
US contemporary SVV isolate USA/SD41901/2015 | 10− 4 | 3000 | + | + | + | 24.3 | 25.7 | 25.6 |
10−5 | 300 | + | + | + | 29.4 | 29.4 | 29.3 | |
10−6 | 30 | + | + | + | 32.7 | 32.7 | 32.7 | |
10−7 | 3 | – | – | – | 35.2 | 36.2 | 34.3 | |
10− 8 | 0.3 | – | – | – | Neg | Neg | Neg | |
10−9 | 0.03 | – | – | – | Neg | Neg | Neg | |
10−10 | 0.003 | – | – | – | Neg | Neg | Neg | |