Table 1.
Susceptibility of tree shrews and ferrets to infection with H9N2 viruses
| Virus strain | Peak titer in nasal wash ± SD (day)a | (+) viral titer in nasal washb | Seroconversion (range of the HI titer)c | |||
|---|---|---|---|---|---|---|
| Tree shrew | Ferret | Tree shrew | Ferret | Tree shrew | Ferret | |
| Y280-wt | 2.34 ± 1.41 (2) | 4.81 ± 0.77(2) | 4/5 | 5/5 | 5/5 (336, 80–640) | 5/5(720, 80–1280) |
| Y280-PB2-E627K | 5.34 ± 0.56 (2) | 5.87 ± 0.50(2) | 5/5 | 5/5 | 5/5 (512, 320–640) | 5/5 (2030, 1280–2560) |
aPeak nasal wash titers are expressed as the mean log10TCID50/mL ± SD
bThe lower limit of detection was 101.5 TCID50/mL on day 2 postinfection
cSerum samples were collected on day 21 postinfection, and the HI titers were determined by using chicken RBCs