Table 1. Growth and pathogenicity of H5N1 viruses.
| Viruses | Virus growth a | Virus pathogenicity in | |||
| log10 EID50/ml | log10 TCID50/ml | Mice b | Ferrets c | Chickens d | |
| Ck/Indo/03 | 8.5±0 | 6.9±0.6 | Low | Low | High |
| VN/04 | 9.5±0 | 9.2±0.1 | High | High | High |
| WS/Mong/05 | 9.0±0 | 8.8±0.3 | High | Moderate | High |
| MDk/VN/05 | 9.3±0.35 | 9.4±0.3 | High | Low | High |
a
All data are the mean±SD from three independent experiments.
b
90–100% mortality in groups of 10 mice after intranasal inoculation with virus dose of 103 EID50 was considered as high pathogenicity; no mortality and disease signs after infection with similar virus dose was considered as low pathogenicity.
c
Severe systemic disease with mortality developed after intranasal infection with virus dose of 106 EID50 was considered as high pathogenicity; severe respiratory disease without mortality was considerate as moderate pathogenicity, and mild or asymptomatic respiratory infection without mortality as low pathogenicity.
d
Intravenous pathogenicity tests [46] with all viruses killing 100% of inoculated chickens indicative of HPAI viruses.