Table 3. Results of study on dissemination of IBV in the chicken and spread of the vaccine strain.
| Days after vaccination of the vaccinated group | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Group | Test | Organ | 2 | 4 | 7 | 9 | 11 | 14 | 16 | 18 | 21 | 25 | 28 |
| Vaccinated chickens (vaccine group) | IHC | Pancreas | – – | + – | – – | – – | – – | – – | – – | ||||
| Trachea | – – | + + | + – | + – | + – | – – | – – | ||||||
| PCR | Cloacal swabs | – – | – – | – – | – – | – – | + – | – – | – – | – – | |||
| Oro-pharyngeal swabs | + + | + + | + + | – – | + – | – – | – – | – – | – – | ||||
| Non-vaccinated chickens of the same age in contact with vaccinated chickens 3 days after vaccination | IHC | Pancreas | – – | – – | – – | + – | – – | – – | |||||
| Trachea | – – | – – | + – | – | – – | – – | |||||||
| PCR | Cloacal swabs | – – | – – | – – | – – | + – | – – | + – | –a | ||||
| Oro-pharyngeal swabs | – – | + – | + – | – – | – – | – – | + – | –a | |||||
| Non-vaccinated chickens of the same age in contact with vaccinated chickens 14 days after vaccination | IHC | Pancreas | – – | ||||||||||
| Trachea | – – | ||||||||||||
| PCR | Cloacal swabs | – – | – – | – – | – – | – – | |||||||
| Oro-pharyngeal swabs | – – | + – | + + | + + | + – | ||||||||
| Non-vaccinated chickens of one day of age in contact with vaccinated chickens 7 days after vaccination | IHC | Pancreas | – – | – – | – – | – – | |||||||
| Trachea | – – | – – | + – | – – | |||||||||
| PCR | Cloacal swabs | + – | – – | – – | – – | – – | – – | ||||||
| Oro-pharyngeal swabs | – – | – – | – – | + – | – – | + – –b | |||||||
– –, no IBV detected; + −, IBV detected in one of the two chickens; ++ IBV detected in both chickens.
a
One chicken was swabbed instead of two.
b
Three chickens were swabbed instead of two.