Table 2.
In vitro and in vivo characteristics of avian–human reassortant influenza viruses
| Reassortant virus | Avian or human virus gene* |
EID50/ml, log10 | pfu/ml | No. of inoculated ferrets/total number |
Peak nasal wash titer (day)§ | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PB2 | PB1 | PA | HA | NP | NA | M | NS | Weight loss (%)† | Sneezing (day of onset) | Virus detected in nasal wash (days p.i.)‡ | ||||
| rgVic | H | H | H | H | H | H | H | H | 9.3 | 5 × 106 | 2/3 (1.4) | 3/3 (2) | 3/3 (1–7) | 5.1 (1) |
| rg486 | A | A | A | A | A | A | A | A | 7.5 | 5 × 105 | 3/3 (21.1) | 0/3 | 3/3 (1–7+) | 6.2 (5) |
| rgVic:486HANA | H | H | H | A | H | A | H | H | 7.8 | 1 × 103 | 1/3 (2.2) | 0/3 | 3/3 (1–7+) | 3.7 (3) |
| rg486:VicHANA | A | A | A | H | A | H | A | A | 7.8 | 4 × 106 | 3/3 (4.1) | 3/3 (2) | 3/3 (1–5) | 5.2 (3) |
| rg486:VicRNP | H | H | H | A | H | A | A | A | 7.5 | 1 × 107 | 2/3 (1.7) | 0/3 | 3/3 (1–5) | 4.7 (3) |
| rg486:VicRNPF5¶ | H | H | H | A | H | A | A | A | 8.3 | 4 × 107 | 3/3 (0.3) | 2/3 (7) | 3/3 (1–5) | 5.1 (3) |
*Avian genes (A) are from HK486 (H5N1), and human genes (H) are from Vic75 (H3N2) virus.
†The percentage mean maximum weight loss is shown.
‡+, the endpoint of virus detection in nasal washes was not determined for all ferrets.
§Peak nasal wash titers are expressed as the mean log10 EID50/ml.
¶rg486:VicRNP was passaged five times in ferrets and then grown in eggs.