<p>Symbols and virus nomenclatures are the same as described in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000072#ppat-1000072-g001" target="_blank">Figure 1</a>. Rescue efficiency represents virus titer (log<sub>10</sub> pfu/ml) from cell cultures at 72 hours after transfection; geometric mean from 3 independent experiments. Plaque formation by reassortant viruses with <100 pfu/ml rescue efficiency was not determined (ND).</p
