Seroprevalence of Neospora caninum and Toxoplasma gondii antibodies in the South American opossum (Didelphis marsupialis) from the city of São Paulo, Brazil.

Antibodies to Neospora caninum and Toxoplasma gondii were assayed in sera of 396 opossums (Didelphis marsupialis) from the city of São Paulo, Brazil. Antibodies to N. caninum were assayed using the indirect immunofluorescent antibody test (IFAT). Antibodies (IFAT, approximately 1:25) to N. caninum were found in 84 opossums (D. marsupialis) in titers of 1:25 in 46, 1:50 in 20, 1:100 in 17, and 1:400 in 1. Antibodies to T. gondii were assayed with the modified agglutination test (MAT) and the IFAT. Antibodies to T. gondii (MAT, approximately 1:25) were found in 82 (20.4%) of the 396 opossums, in titers of 1:25 in 24, 1:50 in 26, 1:100 in 18, 1:200 in 13, and 1:800 in 1. The IFAT antibodies to T. gondii were found in 148 of 396 opossums, in titers of 1:16 in 41, 1:32 in 23, 1:64 in 13, 1:128 in 6, 1:256 in 20, 1:512 in 17, 1:1,024 in 10, 1:2,048 in 10, 1:4,096 in 7, and 1:8,192 in 1. This is the first report of N. caninum and T. gondii infections in D. marsupialis.

Phagocytic activity mediated via Fc gamma R, Fc mu R, and CR3 and H2O2 release during ontogeny of mouse macrophages.

Mouse macrophage phagocytic activity was studied during ontogenetic development by comparing the abilities of infant and adult mouse macrophages to ingest opsonized particles via Fc gamma R, Fc mu R, or CR3. These studies were performed on resident, BCG-, and thioglycollate-stimulated peritoneal macrophages. The percent of ingestion and the index of maximal phagocytosis mediated via Fc gamma R is lower in infant than in adult mouse macrophages. However, the adherence mediated by Fc gamma R is similar to that seen with adult cells. Similar results were obtained when phagocytosis was mediated via Fc mu R or CR3, reaching adult levels during ontogenetic development. We also studied the age-dependent release of H2O2 by peritoneal cells before and after incubation with phorbol myristate acetate. Interestingly, the capacity of peritoneal cells from infant animals to generate H2O2 after BCG infection is similar to that observed in adult mice. Our results suggest that the adherence and phagocytosis mediated by Fc gamma R, although at lower levels than in adults, and the production of microbicidal H2O2 may be relevant for mouse survival during the first days of life.

Prevalência do nematóide Trichosomoides crassicauda em uma colônia convencional de ratos Wistar / Prevalence of the nematode Trichosomoides crassicauda in a conventional Wistar rats colony

Determinou-se a prevalência do nematóide Trichosomoides crassicauda na colônia convencional de ratos Wistar do Biotério Central (DTAEP) da Faculdade de Medicina da USP. Foram examinadas as bexigas urinárias de 365 ratos sendo 130 machos e 133 fêmeas, de 8 a 19 semanas de idade; e 51 machos e 51 fêmeas, com idade acima de 20 semanas, retirados da reproduçäo. Foi também determinada a prevalência de cálculos urinários, os quais têm sido associados à presença do parasita. Os resultados obtidos indicaram que a prevalência do T. crassicauda na colônia foi de 48//(43//em machos e 53//em fêmeas), sendo que o máximo valor observado foi 80//, em machos de 16 semanas de idade. O número médio de parasitas por rato näo ultrapassou o limite de 2,5 em fêmeas de 16 semanas de idade. Näo houve diferença na prevalência de cálculos urinários entre animais parasitados e näo parasitados (10//e 16//, respectivamente), mas esta diferença foi significante entre machos e fêmeas (23//e 4//). Além disso, os cálculos encontrados nos machos (mucóides) foram diferentes daqueles encontrados nas fêmeas (cristais)