Corynebacterium suis infections in swine. 2. Morphological findings in the urinary tract with special reference to the bladder

Morphological investigations of the urethra, urinary bladder (2 localizations), ureter, renal pelvis and kidneys were performed in sows with Corynebacterium suis infection. The first stages of the disease were characterized by changes of the transitional epithelium in the bladder where epithelial vacuolisation, goblet cell differentiation, leucocytic infiltrations, and haemorrhages occurred. In chronically affected animals different stages of a mucopurulent, partly erosive to ulcerative cystitis were observed. Furthermore, chronic cystitis was characterized by polypoid mucosal proliferation and bacterial accumulations. Ureter and urethra showed signs of a mild purulent inflammation. In the renal pelvis there was a severe fibrinopurulent and necrotizing pyelitis which was accompanied by bacterial invasions. The parts of the renal pelvis without desquamation of the transitional epithelium undergo mucoid degenerations. The final stage of the disease is characterized by severe fibrosing chronic interstitial nephritis leading to death of the animals due to uraemia.