Table 3.

Protection scores and protection % in vaccinated specific pathogen free chickens attenuated IBM41, IB2, and IB-Var2 strains after homologous virus challenge.

Group	Challenge virus	Protection Scorea	Protection %b
att-IBM41 vaccinated	WT-IBM41	90.1	100%
att-IB2 vaccinated		88.2	100%
att-IBvar2 vaccinated	WT-IBvar2	85.6	90%
Challenge control-IBM41	WT-IBM41	NAc	0%
Challenge control-IBvar2	WT-IBvar2	NA	0%
Negative control	None	NA	NA

^a,bProtection score [1 – mean ciliostasis score for vaccinated challenged/mean ciliostatsis score for challenge group] × 100 and % of protected chicks showed an average score ≤20 out of all tested chicks (Cook et al., 1999).

^cNA; not applicable.