Table 5. Evaluation of pathogenicity used by clinical signs and re-isolation rate in SPF chickens challenged with a field strain of Avibacterium paragallinarum.

^*Group A and C were vaccinated at 40 days of age; Group A and B were challenged with field strain of ADL121286 at 54 days of age; Group C and D were challenged with field strain of ADL121500 at 54 days of age; Group E was the control group. ^†Average score of severity of clinical signs on a daily basis; Average score within row followed by dissimilar superscript letters are significantly different at p ≤ 0.05. ^‡Number of positive samples/total number of samples tested (positive rate).