Table 2. Infectivity of pH1N1 influenza and precursor viruses for ferrets.
| Virus | Dose (TCID50) of virus administereda | No. seroconverted/totalb | No. shedding virus (Culture pos/total) | 50% ferret infectious dose (FID50)c | Mean peak titer in nasal wash (log10 TCID50/mL) |
| 10 | 1/3 | 1/3 | 3.2 | ||
| Rec pH1N1 | 100 | 3/3 | 3/3 | 18 | 2.4 |
| 10,000 | 3/3 | 3/3 | 4.2 | ||
| 10 | 1/3 | 2/3 | 3.45 | ||
| 6∶2 Reassort | 100 | 3/3 | 3/3 | 18 | 4.95 |
| 10,000 | 3/3 | 3/3 | 3.7 | ||
| 10 | 1/3 | 1/3 | 4.45 | ||
| TRS | 100 | 3/3 | 3/3 | 18 | 3.7 |
| 10,000 | 3/3 | 3/3 | 4.45 | ||
| 10 | 3/3 | 3/3 | 4.3 | ||
| Eurasian | 100 | 3/3 | 3/3 | <10 | 3.7 |
| 10,000 | 3/3 | 3/3 | 3.6 |
a
Virus dose delivered in 500 µL volume.
b
Seroconversion was determined by HAI assay.
c
If the endpoint was not reached at a dose of 10 TCID50, we assumed that at a dose of 1 TCID50 no ferrets would be infected; therefore, the FID50 value is shown as <10.