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Table 3 Protective efficacy of C-KCE-HA against H5N1 lethal virus HM/06 challenge in ducks

From: Efficient strategy for constructing duck enteritis virus-based live attenuated vaccine against homologous and heterologous H5N1 avian influenza virus and duck enteritis virus infection

Challenge virus Challenge time pv Vaccine Virus isolation from the swabs (shedding/total log 10 EID 50 /mL) No. surviving/total
Day 3 pc Day 5 pc Day 7 pc
Oropharyngeal Cloacal Oropharyngeal Cloacal Oropharyngeal Cloacal
HM/06 1 week C-KCE-HA 0/7 0/7 0/7 0/7 0/7 0/7 7/7
C-KCE 7/7(2.1 ± 0.9) 6/7(2.5 ± 0.3) 0/7
PBS 7/7(3.4 ± 1.2) 7/7(3.8 ± 0.4) 0/7
3 weeks C-KCE-HA 0/7 0/7 0/7 0/7 0/7 0/7 7/7
C-KCE 7/7(4.1) 7/7(3.3 ± 0.5) 0/7
PBS 7/7(3.6 ± 0.7) 7/7(2.5 ± 1.1) 0/7
12 weeks C-KCE-HA 0/7 0/7 0/7 0/7 0/7 0/7 7/7
C-KCE 7/7(2.6 ± 0.8) 7/7(3.1 ± 0.6) 0/7
PBS 7/7(2.9 ± 0.6) 6/7(2.3 ± 1.1) 0/7
36 weeks C-KCE-HA 0/7 0/7 0/7 0/7 0/7 0/7 7/7
C-KCE 7/7(2.5 ± 0.6) 5/7(2.8 ± 0.3) 0/7
PBS 7/7(2.7 ± 0.9) 6/7(2.4 ± 0.6) 0/7
  1. One-month-old SPF ducks were used in these studies. Groups of seven ducks were inoculated subcutaneously with 105 PFU of C-KCE-HA, 105 PFU of C-KCE or with PBS as a control. They then were challenged intramuscularly with 100-fold DLD50 heterologous (HM/06) AIVs at 1 week, 3 weeks, 12 weeks or 24 weeks post-vaccination (pv). Oropharyngeal and cloacal swabs were collected on days 3, 5, and 7 post-challenge (pc) and titrated in SPF eggs. All of the ducks in C-KCE and PBS groups died within 5 days. The horizontal line indicates that the animals had died by that time point.