Fig 5.
Replication and transmission of recombinant viruses in ferrets. (A to C) Groups of 3 ferrets were inoculated with the CT-Sw/12043PM-Sw/1130 (A), CT-Sw/1204vRNPM-Sw/1130 (B), or CT-Sw/1204HA-NA (C) reassortant virus. One of three inoculated ferrets was sacrificed 5 days p.i. (†) for tissue viral titration (D) and histopathology (E). RD contacts were housed adjacent to the inoculated ferrets 1 day p.i. for viral exposure (1:1 setup). Each of the transmission test groups consisted of two directly infected animals and two RD contacts. Nasal wash titers are shown for individual ferrets (as indicated by the colors). The limit of virus detection was 1.5 log10 TCID50/ml per g. ‡, seroconversion of RD contacts after exposure to inoculated ferrets as measured by hemagglutinin inhibition assays. (E to G) Hematoxylin and eosin staining of lung tissue from ferrets infected with CT-Sw/12043PM-Sw/1130 (E), CT-Sw/1204vRNPM-Sw/1130 (F), and CT-Sw/1204HA-NA (G) are shown at low (×40) and high (×200; insets) magnifications.