Table 3.
Amino acid at position 226 of the HA gene of viruses recovered from the nasal washes of guinea pigs and ferretsa
| Animal | Sample origin | Virus recovered from animals on different days postinoculation (p.i.) or postexposure (p.e.)a |
|||
|---|---|---|---|---|---|
| Day 2 p.i. | Day 4 p.i. | Day 6 p.i. | Day 5 p.e.b | ||
| Guinea pig | HA/226R-Guinea pig 1 | R (6/6) | Q (6/6) | NA | NA |
| HA/226R-Guinea pig 2 | R (6/6) | R (3/6) + Q (2/6) + L (1/6) | NA | NA | |
| HA/226R-Guinea pig 3 | R (6/6) | R (3/6) + Q (3/6) | Q (6/6) | NA | |
| HA/226R-Guinea pig 4 | R (6/6) | Q (5/6) + L (1/6) | Q (6/6) | NA | |
| HA/226R-Guinea pig 5 | R (6/6) | R (4/6) + Q (2/6) | NA | NA | |
| Ferret | HA/226R-Ferret 1 | R (10/10) | Q (8/10) + L (2/10) | NA | Q (10/10) |
| HA/226R-Ferret 2 | R (10/10) | Q (9/10) + L (1/10) | NA | Q (10/10) | |
| HA/226R-Ferret 3 | R (10/10) | Q (9/10) + L (1/10) | Q (10/10) | Q (10/10) | |
| HA226R+PB2/271T-Ferret 1 | R (10/10) | R (9/10) + L (1/10) | NA | NA | |
| HA226R+PB2/271T-Ferret 2 | R (10/10) | R (9/10) + L (1/10) | NA | NA | |
| HA226R+PB2/271T-Ferret 3 | R (10/10) | R (10/10) | NA | NA | |
We extracted viral RNA from the nasal washes collected from virus-inoculated and virus-exposed ferrets and guinea pigs. The PB2 and HA were amplified and cloned into T vectors. Six to ten molecular clones from each sample were randomly selected and sequenced. No changes in PB2 were detected. For values in parentheses, the number on the left of the slash shows the number of clones bearing the indicated amino acid at position 226 of HA, and the number on the right of the slash shows the total number of clones sequenced. NA, not applicable.
All of the samples collected from the exposed animals were sequenced, and the R226Q reversion in HA was detected in all of the clones; only the data from day 5 p.e. are presented in the table.