Arthritis after experimental infection with Yersinia enterocolitica 0 : 3 in rabbits

Arthritis in rabbits was caused after experimental oral infection with Yers inia enterocolitica (serotype 0:3, biotype 4, pYV(+)). Clinical and laborat ory signs, bacterial dissemination to the viscera, immune response and morp hological findings were studied from dap 1 to day 40 post-infection (p.i.). Augmentation of body temperature and erythrocyte sedimentation rate occurr ed on day 1, and on da) 8 p.i. was accompanied by leucopenia. The number of alveolar macrophages was increased up It, the 15th day p.i., in contrast t o peritoneal macrophage numbers. Extensive bacterial colonization of the in ternal organs was detected at necropsy until the end of the experiment. Ana lysis of the cell immune response revealed activation of B cells in periphe ral blood, spleen and thymus as well as augmentation of T-cell number in th e lymphoid organs examined on daps 15, 28 and 40 p.i. Histological changes typical of a generalized infection, such as purulent meningoencephalitis, c atarrhal pneumonia and lymphadenitis, were observed. Clinical and morpholog ical manifestations of arthritis were also established. The results obtaine d show that Y. enterocolitica (serotype 0:3, pYV(+)) induces a generalized, non-lethal infection in Chinchilla rabbits, complicated by arthritis.