Table 3.
Correlation between serum resistance and virulence of R. anatipestifer isolates

Isolation site	No. of isolates	Serum reaction1		Probability (%)2
		SR	SS
Pharynx	100	4	96	4.0
Internal organs (n=30)	30	30	0	100
Total (n=130)	130	34	96	26.2

SR, serum resistant isolates; SS, serum susceptible isolates.
Probability of serum resistance.