Bovine and ovine mycoplasmal arthritis and synovitis (abstract)

The pathology of mycoplasmal gonitis in a Friesian cow aged 15 months, and polyarthritis in a 3-week-old East Friesian sheep was described. Both stifle joints of the cow, which was 1/63 calves that developed polyarthritis after being fed milk contaminated with Mycoplasma mycoides mycoides large colony type (MmmLC), were distended with yellow flocculent fluid. The capsular and synovial tissues and their associated tendon sheaths were greatly thickened due to chronic active fibrinopurulent inflammation with ulceration of synovial membranes and progressive organisation of the exudate by granulation tissue and fibrosis. Nodular aggregates of lymphocytes and plasma cells studded the membrane. Articular surfaces were unremarkable. Mycoides cluster organisms were demonstrated on polymerase chain reaction (PCR) analysis of the joint tissues and these were confirmed on culture as MmmLC. The lamb was the offspring of an agalactic ewe whose progeny of the previous 3 years developed polyarthritis. The carpal and hock joints had periarticular nodular swellings and there was mild haemarthrosis of all appendicular skeletal joints. Lesions were characterised as subacute active fibrinopurulent synovitis and periarthritis with haemorrhage. Articular surfaces were normal. Joint tissue was positive by PCR for the mycoides cluster of organisms. Mycoplasma was not isolated in culture.