Table 2.
Efficacy of recombinant duck enteritis virus (rDEV) vaccines against the virulent ck/CH/LDL/091022 strain of infectious bronchitis virus (IBV).
| Vaccine | Dose (pfu) | Viral shedding (%)a |
Clinical signs (%)b | Survival (Mortality [%]) | Seroconversion post-vaccination (%) |
||||
|---|---|---|---|---|---|---|---|---|---|
| Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | |||||
| rDEV-N | 106 | 2/10 (20)c | 3/10(30)c | 7/10 (30) | 21/25 (84) | 19/25 (76) | 10/25 (40) | 7/15 (46.7) | 7/15 (46.7) |
| rDEV-S | 106 | 3/10 (30)c | 2/10(20)c | 9/10 (10) | 23/25 (92) | 13/25 (52) | 4/25 (16) | 1/15 (6.7) | 1/15 (6.7) |
| rDEV-S1 | 106 | 4/10 (40)c | 4/10(40)c | 7/10 (30) | 23/25 (92) | 7/25 (28) | 2/25 (8) | 2/15 (13.3) | 1/15 (6.7) |
| rDEV-N & rDEV-S | 106 | 2/10 (20)c | 2/10(20)c | 8/10 (20) | 23/25(92) | 16/25(64) | 13/25(52) | 7/15(46.7) | 7/15(46.7) |
| rDEV-N & rDEV-S1 | 106 | 2/10 (20)c | 2/10(20)c | 9/10 (10) | 25/25(100) | 25/25(100) | 21/25(84) | 11/15(73.3) | 11/15(73.3) |
| Control | – | 9/10 (90) | 8/10(80) | 6/10 (40) | 0/25 (0) | 0/25 (0) | 0/25 (0) | 0/15 (0) | 0/15 (0) |
a
Number of chickens shedding IBV on day 5 post-challenge.
b
Clinical signs (%) are presented as the percentage of birds showed clinical signs out of the total number of vaccinated chickens in the group after virulent IBV challenge.
c
p < 0.01, very significant difference, each group was only compared to the control group.