Table 2.

Clinical signs, virus replication, and seroconversion associated with H9N2 reassortant viruses in direct contact and respiratory-droplet contact ferrets

Direct contacts
Respiratory-droplet contacts
VirusWeight loss (%)*Sneezing (day of onset)Serum (HI titer)Weight loss (%)*Sneezing (day of onset)Serum (HI titer)
2WF10:6M981.65 ± 0.502/2 (4, 5)1280, 2560ND0/2<10, <10
P105.36 ± 0.14/4 (5, 7)2560, 2560, 2560, 25607.91 ± 1.984/4 (7, 8, 9)2560, 2560 1280, 2560
2RCP10:6M982.79 ± 1.434/4 (7, 9)1280, 1280, 1280, 12802.07 ± 0.594/4 (6, 7, 8)1280, 1280, 640, 640
RCP10 (A189, G192)1.67 ± 0.824/4 (5, 7)1280, 1280, 2560, 2560ND0/4<10, <10, <10, <10
RCP10 (T189, R192)8.65 ± 5.164/4 (6, 7)1280, 2560, 2560, 2560ND0/4<10, <10, <10, <10
2WF10: 6RCP102.3 ± 1.44/4 (6, 7)1280, 2560, 1280, 12801.2 ± 0.40/4<10, 40, 640, 40
  • *Average body weight loss is shown as average ± standard deviation.

  • Homologous virus was used in HI assays to detect anti-H9 antibodies (sera collected at 2 weeks p.c.).

  • Two independent experiments with 2 infected, 2 direct, and 2 respiratory droplet ferrets each. ND, not determined, because no viral replication occurred in ferrets.