In a retrospective morphological and microbiological study, 39 of 55 cases of bovine fibrinous pneumonia were diagnosed as fibrinous pleuropneumonia. Twenty-nine of these 39 (74%) were associated with Pasteurella hemolytica, but only two cases (5%) with P. multocida. In contrast, of the 16 cases classified as fibrinous bronchopneumonia, one (6%) was associated with P. hemolytica, and nine (56%) with P. multocida. In eight cases Mycoplasma and Hemophilus somnus were found in association with either P. hemolytica or P. multocida but were never isolated alone. We concluded that the use of the term pasteurellosis, implying Pasteurella as the cause, is imprecise because lesions associated with P. hemolytica fulfill the criteria of a fibrinous pleuropneumonia, whereas P. multocida is more likely to cause a bronchopneumonia with moderate amounts of fibrin.

Eight cases of sessile, intra-articular soft tissue masses originating from the cranio-dorsal attachment of the capsule of the fetlock joint of horses are presented. In 4 of these cases an osteochondral fracture of the first phalanx was also present. Clinically the condition closely resembled villonodular synovitis; however the microscopic changes did not correspond to those reported. The clinical signs included lameness after exercise, joint effusion and pain on manipulation. The offending masses were surgically resected and their histology indicated a chronic proliferative synovitis. The results of these cases indicate that the condition carries a favourable prognosis.

Pasteurella pneumotropica was isolated from the uteri, fetuses, lungs, and spleens of aborting Swiss Carworth mice. Male mice in the colony carried P. pneumotropica in pharynges, testes, and seminal vesicles. Normal pregnant and nongravid females carried P. pneumotropica in the eye of 1 and in the uteri of 4 of 11. Pregnant mice from another colony did not abort when injected with P. pneumotropica. Necrotizing and suppurative metritis was found among aborting females with P. pneumotropica infections. Occurrence of malignant lymphoma and mammary adenocarcinoma among animals in this colony likely resulted in immunosuppression which could have predisposed animals to the diseases seen.

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