Table 3.
Results of vaccination-challenge tests (vaccination with infectious bronchitis virus vaccine strains 4/91 and H120, followed by challenge with isolate ck/CH/LHLJ/140906).
| Group⁎ | Morbidity | Mortality | Antibody response |
Virus recovery† |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Vaccinated |
Challenged |
4 d‡ | 8 d | 12 d | 16 d | |||||||||||
| 4 d‡ | 8 d | 12 d | 16 d | 20 d | 4 d‡ | 8 d | 12 d | 16 d | 20 d | |||||||
| 1 | 0/10 | 0/10 | 0/10 | 0/10 | 5/10 | 8/10 | 10/10 | 10/10 | 10/10 | 10/10 | 10/10 | 10/10 | 3/10 | 1/10 | 0/10 | 0/10 |
| 2 | 0/10 | 0/10 | 0/10 | 0/10 | 5/10 | 9/10 | 10/10 | 10/10 | 10/10 | 10/10 | 10/10 | 10/10 | 5/10 | 1/10 | 1/10 | 0/10 |
| 3 | 0/10 | 0/10 | – | – | – | – | – | 0/10 | 7/10 | 9/10 | 10/10 | 10/10 | 10/10 | 9/10 | 2/10 | 0/10 |
| 4 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 | 0/10 |
Birds in groups 1 and 2 were vaccinated with 4/91 and H120 vaccines, respectively, and challenged with isolate ck/CH/LHLJ/140906. Birds in group 3 were only challenged with IBV isolate ck/CH/LHLJ/140906. Birds in group 4 were not exposed to any viruses and served as negative controls.
Two procedures were used for virus recovery after challenge as described previously (Liu et al., 2009). First, embryos that had been inoculated with individual nasopharyngeal swab samples were observed for lesions. Second, reverse transcription PCR (RT-PCR) using a pair of oligonucleotide primers, N(−) and N(+), was conducted on RNA recovered from the allantoic fluid of the same eggs. The results from the two procedures were identical.
Days after vaccination/challenge.