Reinfection of mice and cats by Toxoplasma gondii Nicolle & Manceaux, 1909: experimental study

• Autor(a) principal: Jamra, Ligia M. Ferreira
• Data de Publicação: 1985
• Outros Autores: Sanchis, Fernando Sogorb, Guimarães, Eny Câmara
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Revista do Instituto de Medicina Tropical de São Paulo
• Texto Completo: https://www.revistas.usp.br/rimtsp/article/view/87428

Experimental reinfection by Toxoplasma gondii in 27 albino mice and 25 domestic cats was studied. Tachyzoites and cysts of AS28 and N strains, by peritoneal and oral route were used. Infection and reinfection were demonstrated by clinical signs, by dye-test and by shedding of oocysts (cats). Mortality of mice was 56%. Infection by the AS28 strain, with low virulence, chronic evolution and cysts in brain, gave some protection to reinfection, manifested by a lower mortality (12.5%) and mice survival. The same occurred when a virulent strain was attenuated by administration of Sulfamonometoxine. Domestic cats were reinfected by ingestion of Toxoplasma cysts, in spite of the presence of a first infection with tachyzoites or cysts by peritoneal or oral via. Mortality was 28% between 4 and 7 1/2 months after infection. After reinfection 48% had higher titers, 44% had unchanged titers and 8% had lower titers. Oocyst shedding after the first infection was 60%, oocyst reshedding was 25%. After the third infection there was no elimination. Shedding of oocysts was observed only after administration of cysts by oral route. Presence of previous serum antibodies of maternal or post-infection origin had no influence neither on immunological response nor on oocysts elimination. Parasites were recovered on 88.2% of the cats and were more frequent in mesenteric lymphonodes and in small intestine; in this organ Toxoplasma was present around 14 months after infection. Wellnouri- shed cats presented ascending titers in dye-test, oocysts shedding in 72% of the animals and reshedding in 30%. Malnourished cats presented low or descending titers, oocysts elimination in 28,5% and no reelimination. Experimental reinfection of cats by Toxoplasma gondii was obtained but the reshedding was infrequent and with fewer oocysts.