TABLE 1.
Summary of groupsa
| Group | Primary influenza strain | Length of time between infections (mo) | Second influenza strain | DPI after last strain inoculation |
|---|---|---|---|---|
| Naive | NA | NA | NA | NA |
| H1N1 | CA/09 | NA | NA | 2, 3, 5, 7, 14 |
| H5N1 | VN/04 | NA | NA | 2, 4, 5, 6, 7 |
| H1N1/H5N1 | Mex/09 | >2 | VN/04 | 2, 4, 6, 18 |
| H3N2/H5N1 | Perth/09, Vic/11 | >3 | VN/04 | 2, 4, 6 |
| H3N2/H5N1 | Vic/11 | 1 | VN/04 | 7, 16, 23 |
a
Ferrets were divided into 6 groups and sacrificed at the time points listed in the last column. See Table S1 in the supplemental material for further information. Abbreviations: CA/09, A/California/07/2009; VN/04, A/Viet Nam/1203/2004; Mex/09, A/Mexico/4108/2009; Perth/09, A/Perth/16/2009; Vic/11, A/Victoria/361/2011; NA, not applicable.