Histo- and immuno-pathological studies on experimental Mycoplasma synoviae infection of the chicken

Abstract

Mycoplasma synoviae strains WVU 1853 and F 2−c AS were administered intranasally or into the hock-joint of 4-week-old specific pathogen-free chickens. The findings obtained by histopathological and immunofluorescent examinations for 8 weeks after inoculation were collated with clinical, bacteriological and serological data. Chickens inoculated intra-articularly developed acute articular lesions that were not paralleled by the recovery of mycoplasmas; those given strain F 2−c AS intranasally (FN chickens) showed gradual development of chronic articular lesions. Myocardial lesions, including Aschoff body-like granulomas, and glomerulo-nephritis with occasional crescent formation, were observed in all groups. At the 4th week and thereafter, generalized vasculitis was seen, especially in FN chickens. These lesions were associated with atrophy of the cortex of the thymus and of the follicles of the bursa of Fabricius, and also with proliferation of plasma and reticulum cells in peripheral lymphoid tissues. In all groups, granular IgG deposits were observed by the fluorescent antibody technique at the site of vascular and renal lesions. The possibility of M. synoviae infection in chickens as a chronic immune disease is discussed.