TABLE 5.
H5 ca viruses exhibit ts and ca phenotypesa
| Virus | Mean virus titer (log10 TCID50/ml) ± SD at temp |
Presence of phenotype |
|||
|---|---|---|---|---|---|
| 39°C | 33°C | 25°C | tsb | cac | |
| dk/Hok/00 wt | 7.3 ± 0.15 | 7.3 ± 0.17 | 3.1 ± 0.09 | − | − |
| dk/Hok/00 ca | 4.3 ± 0.15 | 8.0 ± 0.17 | 7.5 ± 0.13 | + | + |
| ck/Egy/10 | 8.3 ± 0.16 | 7.2 ± 0.13 | 5.0 ± 0.2 | − | − |
| Egy/09 ca | 5.3 ± 0.21 | 8.7 ± 0.2 | 7.5 ± 0.12 | + | + |
a
CEK cells were inoculated with H5 wt and ca viruses and incubated in incubators at 39°C, 33°C, and 25°C. After incubation for 6 days at 39°C and 33°C or 10 days at 25°C to reach peak titers, cells were examined for cytopathic effects, and virus titers at each temperature were determined.
b
ts, difference between the mean titer at 33°C and that at 39°C of ≥100-fold.
c
ca, difference between the mean titer at 33°C and that at 25°C of ≤100-fold.