Synovitis induced by intra-articular inoculation of inactivated Mycoplasma mycoides in calves

Abstract

The intra-articular inoculation of heat-inactivated M. mycoides in young calves induced an acute fibrino-purulent synovitis, which progressed to a chronic proliferative synovitis. Intra-articular inoculation of heat-inactivated M. laidlawii also induced an acute fibrinous synovitis in young calves. It is postulated that factors which induce increased vascular permeability and fibrinous exudation are released from concentrated suspensions of dead mycoplasmas. Focal connective tissue necrosis was seen in synovia of joints inoculated with inactivated M. mycoides. The formation of fibrin deposits was the primary pathogenic factor in the acute synovitis, and the progression to a chronic proliferative synovitis is attributed to persistence of these deposits and a concomitant disturbance of physiological mechanisms associated with the synovial membrane. Intra-articular inoculation of fluid used to wash harvested M. mycoides induced chronic synovitis. Extensive washing of the organisms did not reduce the pathogenicity of the inactivated preparation. The possibility that M. mycoides released endotoxin-like factors after death of the cell is discussed.