Group a Total Score Reduced Percentage The Score of Gross Lesions b Brain Serosa Joint Spleen Liver Lung Vaccination 7 75% c 1(1/3) d 0(0/3) 3(1/3) 0(0/3) 0(0/3) 3(1/3) Control 27   1(1/3) 7(3/3) 7(3/3) 1(1/3) 4(2/3) 7(3/3) aVaccination: S. suis2+rSao, Control: sterile saline. bNolesion = 0, lesion area<33% = 1, lesion area 33– 66% = 3, lesion area>66% = 5. cDifferences between groups were analyzed by Student’s t-test P<0.05. dThe number of piglets in a group that was confirmed to have the presence of S. suis serotype 1 bacteria.

Table 2: Reduced percentage of pathological lesion score after challenge with heterologous Streptococcus suis serotype 1 bacteria.