RESUMO
Peritoneal macrophages from Wistar rats, inoculated and non-inoculated with 10(6) T. lewisi trypomastigotes, were cultured and infected with 10(6) T. gondii tachyzoites. Multiplication rates of this parasite were studied after 1, 24 and 48 h of infection but there were not significant differences between the number of parasites found inside of macrophages coming, either from T. lewisi infected or non infected rats. On the other hand, in vivo studies of Toxoplasma multiplication inside peritoneal macrophages, showed that there is an increase of parasite number in cells from T. lewisi infected rats, as compared with those macrophages from non infected rats. This effect was statistically significant and was more evident after four days of infection. Therefore, it has been demonstrated that in vivo, but not in vitro T. lewisi infections, causes an important decrease of the natural resistance to T. gondii of the white rats, which is manifested by the major invasion and multiplication of the parasite inside of peritoneal macrophages.
Assuntos
Macrófagos Peritoneais/parasitologia , Toxoplasma/crescimento & desenvolvimento , Toxoplasmose/imunologia , Trypanosoma lewisi/imunologia , Animais , Imunidade Inata , Ratos , Ratos Sprague-Dawley , Ratos WistarRESUMO
An in vivo model to study the antimalaric effect of plant extracts is described. White mice (25-30 g body weight) are treated subcutaneously with 0.6 ml of the diluted extract starting seven days before P. berghei infection; treatment continues until death or for 30 days. Simultaneously 0.2 ml of the extract are applied per os starting three days before infection. In a test of the model, treated and non-treated animals differed in body weight, survival time, haematocrite, parasitemia development, and spleen or liver weight of recent dead or killed mice.
Assuntos
Antimaláricos/farmacologia , Malária/tratamento farmacológico , Extratos Vegetais/farmacologia , Plasmodium berghei/efeitos dos fármacos , Animais , Camundongos , Extratos Vegetais/uso terapêutico , Fatores de TempoRESUMO
Cotton rats (Sigmodon hispidus) were collected from Ojo de Agua, Alajuela (N = 74) and Cañas, Guanacaste (N = 29). Feces had 31 E. sigmodontis, nine E. tuskegeensis, eight E. roperi, three E. webbae and two Eimeria sp. This is the first report of these coccidian parasites for Costa Rica.
Assuntos
Eimeria/classificação , Sigmodontinae/parasitologia , Animais , Costa RicaRESUMO
To demonstrate that T. lewisi infection increases T. gondii multiplication in white rats, groups of five Wistar or Sprague Dawley rats were inoculated with 10(6) T. lewisi trypomastigotes and four or seven days later infected with Toxoplasma tachyzoites. Host survival time was monitored, and the presence of T. gondii was confirmed in all dead rats by studying peritoneal exudate smears and lung tissue sections stained with haematoxylin-eosin. The presence of Toxoplasma cysts or antibodies was checked in the brain of surviving rats. The increase is observed four days after trypanosome inoculation and is dependent on rat strain, but not on inoculum size or rat age. Humoral and cellular factors may have a role in the increase as has been reported for other experimental infections with African trypanosomes and T. cruzi.
Assuntos
Toxoplasmose Animal/parasitologia , Trypanosoma lewisi , Animais , Interações Hospedeiro-Parasita/imunologia , Tolerância Imunológica/imunologia , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Toxoplasmose Animal/imunologiaRESUMO
Differences in Toxoplasma gondii dissemination in white rats (Sprague Dowley) and mice (Wistar) after oral oocyst inoculation are described. Groups of five animals (both hosts) were infected per os with oocysts of the TCR-2 avirulent strain and the dissemination pattern was compared in brain tissue or by serology. Early dissemination was similar in both species. One hr after infection the parasite was present in blood and peritoneal exudate as well as in heart, lung, liver, spleen, lymph nodes and brain. However, after five days there were important differences between both hosts and after 30 days, the parasite was detected only in rat heart and brain, while in mice it persisted in fluids and all organs.
Assuntos
Toxoplasma/patogenicidade , Animais , Gatos , Camundongos , Camundongos Endogâmicos C3H , Ratos , Ratos Sprague-Dawley , Ratos WistarRESUMO
Presence of T. gondii in meat from several sources was determined by traditional methods and by a new simplified method in which animals are fed meat directly without any previous treatment with artificial gastric fluid. Tissues are ground and the animals ingest them naturally. Determination of Toxoplasma in lungs or brain (as well as by specific antibody test), showed no statistically significant differences between both methods.
Assuntos
Parasitologia de Alimentos , Carne/parasitologia , Toxoplasma/isolamento & purificação , Animais , Bovinos , Camundongos , Fatores de TempoRESUMO
Sigmodon hispidus, a cotton rat, was inoculated with tachyzoites or oocysts of Costa Rican strains of Toxoplasma gondii to demonstrate the resistance to this parasite, as compared with mice, hamster and white rat infection. Susceptibility to tachyzoite inoculation was higher in this animal than in white rats but lower than in the other animals. Independent to the Toxoplasma strain studied, oocyst infection was less lethal for S. hispidus when compared with mice and hamsters; the results were similar to those observed for white rats. There is a probable participation of this wild animal in the natural Toxoplasma life cycle.
Assuntos
Toxoplasma/fisiologia , Toxoplasmose Animal/imunologia , Animais , Cricetinae , Suscetibilidade a Doenças , Imunidade Inata , Mesocricetus , Camundongos , Camundongos Endogâmicos , Ratos , Ratos Sprague-Dawley , SigmodontinaeRESUMO
Groups of 1, 5, 10, 15 and 30 day old rats (Sprague Dawley) and Wistar mice were infected per os with different inocula of Toxoplasma gondii oocysts from an avirulent strain. Infection pattern was followed by determination of survival time, tissue lesions, parasite presence and serology. Although all the animals survived the total experimental period (30 day), there were important differences between both rodents regarding to Toxoplasma natural resistance. Brain cysts, as well as tachyzoites in other organs were regularly present in mice but not in rats. On the other hand, most of the organs from mice presented characteristic T. gondii lesions, while in rats a normal tissues were observed, with the exception of an acute reaction found in the brain of a 15d old animal.
Assuntos
Toxoplasma/fisiologia , Toxoplasmose/imunologia , Fatores Etários , Animais , Encéfalo/parasitologia , Imunidade Inata/imunologia , Camundongos , Ratos , Ratos Sprague-Dawley , Toxoplasmose/mortalidade , Toxoplasmose/parasitologiaRESUMO
Samples of muscle, heart, liver and lung were tested for the presence of Toxoplasma gondii using mice as a biologic detector and the carbon immunoassay (CIA) for immunological diagnosis. In positive tissues the percentage of samples positive ranged from 10 to 50% which indicates the importance of cattle in the epidemiology of Toxoplasma in Costa Rica. We discuss these findings in relation to the transmission of the parasite in Costa Rica.
Assuntos
Doenças dos Bovinos , Carne/parasitologia , Toxoplasma/isolamento & purificação , Toxoplasmose Animal/transmissão , Animais , Bioensaio , Bovinos , Costa Rica , Coração/parasitologia , Imunoensaio/métodos , Fígado/parasitologia , Pulmão/parasitologia , Camundongos , Músculos/parasitologiaRESUMO
Las cucarachas Eurycotis biolleyi y Blatella germanica ingieren heces de gato aún en presencia de azúcar, queso o masa de maíz. Además, los ooquistes de Toxoplasma pueden mantenerse viables externa e internamente en esos insectos hasta 19 días después de la exposición experimental. Se agregan así dos nuevos vectores mecánicos en la transmisión de T. gondii