TABLE 1.
Characteristics of influenza A H5N1 viruses
| Virus | Groupa | Case description
|
Passage no.
|
Infectivity titer (log10/ml)b
|
MID50c | LD50d | |||
|---|---|---|---|---|---|---|---|---|---|
| Age (yr)/gender | Outcome | MDCK | Eggs | TCID50 | EID50 | ||||
| HK/483 | B | 13/female | Fatal | 1 | 3 | 8.5 | 9.0 | 2.2 | 2.4 |
| HK/485 | B | 24/female | Severe/recovered | 2 | 2 | 8.5 | 8.7 | 1.1 | 2.9 |
| HK/156 | A | 3/male | Fatal | 0 | 3 | 7.7 | 10.0 | 3.2 | 5.9 |
| HD/486 | A | 5/female | Mild/recovered | 2 | 4 | 8.7 | 9.0 | 1.2 | >7 |
| X-31 (H3N2) | NAe | NA | 0 | >10 | 7.3 | 8.5 | 0.7 | >5.2 | |
a
Antigenic/genetic group of H5N1 viruses isolated from humans (3).
b
Calculated by the method of Reed and Muench (24) from the results of serial titrations of viruses in MDCK cells and embryonated eggs.
c
Expressed as the EID50 required to give 1 MID50.
d
Expressed as the EID50 required to give 1 LD50.
e
NA, not applicable.