TABLE 2.
Lethality of the H5N1 avian influenza isolates in chickens and mice
| Virus | Titer of virus stock (log10 EID50/ml) | IVPIc | Virus titers in organs of mice (log10 EID50/ml ± SD)a
| MLD50 (log EID50)b | |||
|---|---|---|---|---|---|---|---|
| Lung | Spleen | Brain | Kidney | ||||
| BHGs/QH/1/05 | 6.7 | 3.0 | 5.7 ± 0.6 | 1.3 ± 0.1 | 2.2 ± 0.3 | 1.8 ± 0.2 | <0.5 |
| BHGs/QH/2/05 | 6.3 | 3.0 | 4.3 ± 0.1 | + | < | < | >6.0 |
| BHGs/QH/3/05 | 8.5 | 3.0 | 6.3 ± 0.9 | 2.0 ± 0.3 | 2.9 ± 0.7 | 2.5 ± 0.3 | <0.5 |
| BHGull/QH/1/05 | 7.3 | 3.0 | 5.6 ± 0.7 | 1.6 ± 0.3 | 1.6 ± 0.1 | 1.6 ± 0.1 | <0.5 |
| GBHGull/QH/1/05 | 7.0 | 3.0 | 6.1 ± 0.2 | 1.6 ± 0.3 | 1.6 ± 0.1 | 1.8 ± 0.2 | <0.5 |
| GC/QH/3/05 | 7.8 | 3.0 | 5.9 ± 0.5 | 1.3 ± 0.0 | 1.6 ± 0.2 | 1.6 ± 0.2 | <0.5 |
| WS/QH/1/05 | 7.5 | 3.0 | 6.5 ± 0.7 | 1.5 ± 0.1 | 1.5 ± 0.1 | 1.8 ± 0.4 | <0.5 |
| RS/QH/1/05 | 7.3 | 3.0 | 6.7 ± 1.0 | 3.3 ± 0.3 | 2.9 ± 0.6 | 3.3 ± 0.3 | <0.5 |
aSix-week-old BALB/c female mice were infected intranasally with 106 EID50 of virus in a 50-μl volume. Three mice from each group were euthanized on day 3 postinoculation, and virus in the organs was titrated in eggs. SD, standard deviation; +, virus was detected only in undiluted samples; <, virus was not detected.
bThe MLD50 dose was determined by inoculating groups of five 6-week-old female mice intranasally with 10-fold serial dilutions of each virus containing doses ranging from 101 to 106 EID50 in 50 μl.
cThe IVPI was determined according to recommendations of the Office International des Epizooties (14).