Pathological and immunohistochemical studies in rabbits experimentally infected with Toxoplasma gondii

Experimental toxoplasmosis was induced in rabbits using different routes. A total of 42 animals were used; 36 of them were in the experimental groups and the other six comprised the control group. In addition, five guinea pigs were used for preparing hyperimmune sera against Toxoplasma gondii. The Ankara strain was inoculated intravenously (group 1, n: 12), intraperitoneally (group 11, n: 12) and intradermally (group III, n: 12) into the rabbits. Group IV animals were kept as controls (n: 6). Clinical and macroscopical findings varied according to the routes of inoculation and organs affected. Microscopically, multifocal necrosis with T. gondii tachyzoites was the main lesion in group I. In group 11, necrotic lesions started at the serosal surfaces of the abdominal organs. In both groups, lesions were distributed in and invaded the deep parts of organs in accordance with post-inoculation days. In group 111, lesions characterized by chronic inflammatory changes and tissue cysts were detected in the brain, liver and spleen in particular. Immurohistochemically, it was observed that positive reactions were not only observed in the tachyzoites and tissue cysts but also detected in antigenic clusters of destroyed organism on the serosal surfaces of the organs in the abdominal cavity.