抄録
Among 4-to 5-week-old albino rats was noted sporadically a disease characterized by redness and severe oedematous swelling in the extremity of four paws. The hind paws were more frequently affected and tibio-tarsal articulation was most severely affected (Photo 1) . No organisms were detected by culture of exudation of affected articulation, liver, spleen and heart blood on blood agar and PPLO media. However, in the articular lesions innumerable Trypanosomes were observed on smear preparations (Photo 2), and young rats which were inoculated with affected tissue materials subcutaneously in the foot showed a similar lesion associated with a large number of the protozoa. Histopathologic examination revealed purulent arthritis associated with infiltration of polymorphnuclear leucocytes in neighbouring subcutaneous and muscular tissues (Photo 3, 4) . In some joints the formation of granulation tissue was remarkable.
