Abstract
A 30-day-old piglet showed severe emaciation. Macroscopically, fibrinous pleuropneumonia was detected. Histopathologically, necrotic lesions were found in the pleura, epicardium, and renal medulla, and were surrounded by numerous necrotic neutrophils. Gram-negative bacterial colonies were seen in the lesions. Similar lesions were also observed in the liver, spleen, mesenterium, and brain. Immunohistochemically, the bacteria were positively reacted with rabbit anti Actinobacillus suis serum. 16S rRNA gene segment from genomic DNA isolated from formalin-fixed paraffin-embedded tissue sections was amplified, and the base sequence analysis results indicated high homology with A. suis (100% similarity, based on a comparison of 650 bp). The present results indicated that A. suis caused necrotic pleuropneumonia, epicarditis and nephritis in the piglet.
