TABLE 3.

Ferret postexposure neutralizing antibody titers and virus shedding after rechallenge

VirusStudy groupNeutralizing antibody titer in ferretaVirus shedding after rechallenge in ferretb
InoculatedContact 1Contact 2InoculatedContact 1Contact 2
HK/0311:5,120<<NDNDND
21:5,120c<c1:80c+
VN/0411:1,280c<c<cNDNDND
2NAVc<c<cNAV++
VN/0511:1,280c<c1:1,280cNDNDND
2NAVcNAVc<cNAVNAV+
TK/0611:2,560c<c<c++
  • a Sera were collected from the one inoculated ferret and the two contact ferrets in each experimental group after they had been housed together for 21 days. Neutralizing antibodies to homologous virus (100 TCID50) were titrated in MDCK cells. NAV, not available (animal died due to severe symptoms during the transmission experiment); <, titer of <1:20.

  • b Ferrets that survived the transmission experiments were rechallenged intranasally with 103 TCID50 of homologous virus. Nasal washes and rectal swabs were collected every other day to detect virus shedding. +, virus shedding detected; −, virus shedding was not detected; ND, rechallenge of the homologous virus was not done in these ferrets.

  • c This ferret exhibited an antibody titer of 1:20 to 1:80 against A/New York/55/04 (H3N2) virus by hemagglutination inhibition assay prior to the experiment.