All female Fitch ferrets were obtained from Triple F Farms (Sayre, PA). Ferrets were selected after screening blood samples for the presence of influenza antibodies using a hemagglutination inhibition assay (HI). Ferrets that were seronegative for seasonal and pandemic viruses were shipped directly to the University of Louisville Regional Biocontainment Laboratory and acclimated for seven days prior to initiation of the studies. Animals were fed Teklad Laboratory Diet #2072 (Harlan/Teklad, Madison, WI) and water ad libitum.