Recombinant virus | IVPIs |
---|
SY (wild-type) | 3 |
rSY-Δ10 | 3 |
rSY-Δ11 | 2.89 |
rSY-Δ10/11 | 2.86 |
- 6-week-old SPF white leghorn chickens (10 chickens per group) were inoculated intravenously with 0.1 mL of 1:10 dilution of allantoic fluid containing each virus. Experimental SPF chickens were monitored daily for clinical signs of disease for 10 days, and the intravenous pathogenicity indexes (IVPI) were calculated according to the recommendation of the OIE.