Crescimento e diferenciação "In vitro" de cepas de Trypanosoma cruzi, isoladas de animais silvestres

In the course of this work, four strains of sylvatic Trypanosoma cruzi were studied in regard to their growth and differentiation in LIT medium. R52, R64, and R65 were isolated from individual Didelphis albiventris (Marsupialia) and M226 from Calomys callosus (Rodentia). The evolution of the numerical incresase and morphogenesis of the trypanosome populations in the culture was observed at regular intervals during a period of 312 hours. Differential counts were made of amastigotes, epimastigotes, and trypomastigotes in Neubauer chambers. Results showed that the four strains had characteristic behavior patterns. M226 increased the most and was followed by R65, R52, and then R64.Foram estudadas três cepas de T. cruzi isoladas de Didelphis albiventris (R52, R64 e R65) e uma isolada de Calomys callosus (M226), quanto ao comportamento "In vitro" no meio LIT. A evolução da população dos tripanossomas com relação ao crescimento e morfogênese foi acompanhada por um período de 13 dias (312 horas), em intervalos regulares. As contagens diferenciais, separando-se formas amastigotas, epimastigotas e tripomastigotas, foram realizadas na câmara de Neubauer. Os resultados obtidos levaram à conclusão de que as 4 cepas estudadas têm comportamento distintos. O melhor crescimento obtido ocorreu para a cepa M226, seguindo-se por ordem decrescente a R65, R52 e R64. Os picos das populações ocorreram como segue: M226, entre 192-264 horas; R65 entre 168-240 horas; R52 às 240 horas e R64 entre 264-312 horas

Estudo experimental de Zygodontomys lasiurus (Rodentia-cricetidae) com cepas de Trypanosoma cruzi

São apresentados resultados em relação a infecção expertmental de Zygodontomys lasiurus (Rodentia-Cricetidae) com duas cepas de T. cruzi isoladas de casos humanos, Y e Berenice, e uma isolada de um triatomíneo silvestre, chamada costalimai. Foram realizados estudos em relação a evolução da parasitemia, duração da patência e prepatência da infecção. Com o objetivo de verificar a agressividade e tropismo tissular das cepas de T. cruzi nesta espécie de roedor, foram também realizados estudos histopatológicos. Os resultados obtidos mostraram que os níveis de parasitemias foram baixos para as três cepas estudadas. A patência da infecção variou de 14 a 16 dias nos animais inoculados com a cepa Y, 26 a 29 dias com a Berenice e 9 a 13 dias com a costalimai. O período prepatente variou de 3 a 5 dias nos animais inoculados com a cepa Y, de 2 a 6 dias com a cepa Berenice e de 6 a 8 dias com a costalimai. As três cepas apresentaram em Z. lasiurus, comprometimento nitidamente muscular, provocando reações leves, moderadas e intensas.Studies on the experimental infection of Zygodontomys lasiurus (Rodentia-Cricetidae) are presented in the current paper. Three strains of T. cruzi were used in the experiments: two, Y and Berenice, were originated from human infection, while the third one was obtained from natural infection in a wild bug Triatoma costalimai. The evolution of the parasitemia was studied and the prepatent and patent periods determined. The tissular tropism and aggressiveness of the strains of T. cruzi were verified through histopathological studies. Results have shown that the parasitemia was always kept at low levels for all the strains. The prepatent period in the infected rodents varied from: 3 to 6 days in the Y strain; 2 to 6 days in the Berenice strain; 6 to 8 in the costalimai strain. The patent period showed the following duration patterns: 14 to 16 days in the Y strain; 26 to 29 in the Berenice strain and 6 to 8 days in the costalimai strain. Tissue damage was predominantly muscular, and the pathological reactions varied from slight to severe

First finding of Triatoma costalimai naturally infected by Trypanosoma cruzi : study of biological aspects of the isolated sample

Uma amostra de T. cruzi foi isolada pela primeira vez de um exemplar do Triatoma costalimai, capturado no município de Mambai, Goiás. Estudos experimentais sobre infectividade e virulência foram conduzidos em triatomíneos, Calomys callosus (Rodentia) e camundongos albinos. Cultivo "In Vitro" da amostra isolada foi obtido com sucesso utilizando-se o meio LIT. As mensurações realizadas em tripomastigotas sanguícolas deram os seguintes resultados (mcg): comprimento total - 16,4 (± 1,1); flagelo livre - 4,9 (± 1,1); largura - 2,8 (± 0,6); distância NA - 4,8 (± 0,6); distância NP - 6,0 (± 0,5) e Indice nuclear 1,3.Tripanosoma cruzi is for the first time recorded infecting Triatoma costalimai captured in Mambaí couty, state of Goiás, Brasil. The isolated strain is easily cultivated on LIT medium. The above T. cruzi strain was inoculated in mice and in Calomys callosus (Rodentia). The infection can be considered mild in those animals. The prepatent period was 9,4 days for mice and 4,8 days for C. callosus. No lethality for C. callosus was observed during the period of observations. The maxima observed parasitemia was: 366.6/5 [cubic milimeters] for mice and 3,750/5 [cubic milimeters] for C. callosus. Pseudocysts were found in muscles cells of both infected rodent species. Cross-immunity tests showed that a previous infection gives resistance against reinoculation with a virulent T. cruzi strain. Nymphs of Dipetalogaster maximus, Rhdnius neglectus and T. infestans fed on infected animals acquired the infection

Primeiro encontro do Triatoma costalimai naturalmente infectado pelo Trypanosoma cruzi: estudo de aspectos biológicos da amostra isolada First finding of Triatoma costalimai naturally infected by Trypanosoma cruzi: study of biological aspects of the isolated sample

Uma amostra de T. cruzi foi isolada pela primeira vez de um exemplar do Triatoma costalimai, capturado no município de Mambai, Goiás. Estudos experimentais sobre infectividade e virulência foram conduzidos em triatomíneos, Calomys callosus (Rodentia) e camundongos albinos. Cultivo "In Vitro" da amostra isolada foi obtido com sucesso utilizando-se o meio LIT. As mensurações realizadas em tripomastigotas sanguícolas deram os seguintes resultados (mcg): comprimento total - 16,4 (± 1,1); flagelo livre - 4,9 (± 1,1); largura - 2,8 (± 0,6); distância NA - 4,8 (± 0,6); distância NP - 6,0 (± 0,5) e Indice nuclear 1,3.<br>Tripanosoma cruzi is for the first time recorded infecting Triatoma costalimai captured in Mambaí couty, state of Goiás, Brasil. The isolated strain is easily cultivated on LIT medium. The above T. cruzi strain was inoculated in mice and in Calomys callosus (Rodentia). The infection can be considered mild in those animals. The prepatent period was 9,4 days for mice and 4,8 days for C. callosus. No lethality for C. callosus was observed during the period of observations. The maxima observed parasitemia was: 366.6/5 [cubic milimeters] for mice and 3,750/5 [cubic milimeters] for C. callosus. Pseudocysts were found in muscles cells of both infected rodent species. Cross-immunity tests showed that a previous infection gives resistance against reinoculation with a virulent T. cruzi strain. Nymphs of Dipetalogaster maximus, Rhdnius neglectus and T. infestans fed on infected animals acquired the infection

Results of the experimental infection of Calomys callosus (Rodentia) with human strains of Trypanosoma cruzi

São apresentados resultados sobre a infecção experimental de Calomys callosus (Rodentia) e duas cepas (Y e Berenice) de Trypanosoma cruzi, isoladas de casos humanos. O estudo da evolução foi feito comparado com Mus musculus albino cepa "Swiss", quanto a prepatência, parasitemia, patência e letalidade. Análise histopatológica foi também conduzida em C. callosus, com o objetivo de verificar o tropismo tissular e agressividade das cepas neste roedor. Os experimentos mostraram que a evolução da infecção em C. Callosus foi diferente para as duas cepas de T. cruzi. A cepa Y apresentou maior parasitemia do que a cepa Berenice. O período prepatente variou com as doses utilizadas tendo sido mais curto nos animais inoculados com a cepa Y (2, 2-5, 2 dias) do que naquelas com a cepa Berenice (3, 2-7 dias). Embora as duas cepas inoculadas nos C. callosus tenham-se mostrado miotrópicas, as alterações tissulares foram mais acentuadas com a Y. Os resultados obtidos abrem perspectivas quanto à possibilidade do uso de C. callosus como animal experimental para T. cruzi.An albino "swiss" strain of Mus musculus was used for comparison purposes with regard to the following parameters: parasitemia, prepatent period, patency of the infection and lethality. Histopathological studies were carried out with the aim of observing the tissue tropism and aggressiveness of T. cruzi against C. callosus. The experiments showed that the evolution of the infection in C. callosus was different according to the two T. cruzi strains utilized. They strain produced higher parasitemia than the Berenice strain. The prepatent period varied as a result of the inocula being shorter in the animals inoculated with the strain Y (2, 2-3, 2 days) than in those infected with the Berenice strain (3, 2-7, 0 days). Although both strains were shown to be myotropic, the tissue alterations were more pronounced in the animals inoculated with the Y strain. Results indicated the possibility that C. callosus may be used as experimental animals for T. cruzi infection

Growth and differentiation "In vitro" of strains of Trypanosoma cruzi isolated from wild animals

Foram estudadas três cepas de T. cruzi isoladas de Didelphis albiventris (R52, R64 e R65) e uma isolada de Calomys callosus (M226), quanto ao comportamento "In vitro" no meio LIT. A evolução da população dos tripanossomas com relação ao crescimento e morfogênese foi acompanhada por um período de 13 dias (312 horas), em intervalos regulares. As contagens diferenciais, separando-se formas amastigotas, epimastigotas e tripomastigotas, foram realizadas na câmara de Neubauer. Os resultados obtidos levaram à conclusão de que as 4 cepas estudadas têm comportamento distintos. O melhor crescimento obtido ocorreu para a cepa M226, seguindo-se por ordem decrescente a R65, R52 e R64. Os picos das populações ocorreram como segue: M226, entre 192-264 horas; R65 entre 168-240 horas; R52 às 240 horas e R64 entre 264-312 horas.In the course of this work, four strains of sylvatic Trypanosoma cruzi were studied in regard to their growth and differentiation in LIT medium. R52, R64, and R65 were isolated from individual Didelphis albiventris (Marsupialia) and M226 from Calomys callosus (Rodentia). The evolution of the numerical incresase and morphogenesis of the trypanosome populations in the culture was observed at regular intervals during a period of 312 hours. Differential counts were made of amastigotes, epimastigotes, and trypomastigotes in Neubauer chambers. Results showed that the four strains had characteristic behavior patterns. M226 increased the most and was followed by R65, R52, and then R64

Morphological aspects of the myocarditis and myositis in Calomys callosus experimentally infected with Trypanosoma cruzi: fibrogenesis and spontaneous regression of fibrosis

Calomys callosus a wild rodent, is a natural host of Trypanosoma cruzi. Twelve C. callosus were infected with 10(5) trypomastigotes of the F strain (a myotropic strain) of T. cruzi. Parasitemia decreased on the 21 st day becoming negative around the 40th day of infection. All animals survived but had positive parasitological tests, until the end of the experiment. The infected animals developed severe inflammation in the myocardium and skeletal muscle. This process was pronounced from the 26 th to the 30th day and gradually subsided from the 50 th day becoming absent or residual on the 64 th day after infection. Collagen was identified by the picro Sirius red method. Fibrogenesis developed early, but regression of fibrosis occurred between the 50th and 64th day. Ultrastructural study disclosed a predominance of macrophages and fibroblasts in the inflammatory infiltrates, with small numbers of lymphocytes. Macrophages had active phagocytosis and showed points of contact with altered muscle cells. Different degrees of matrix expansion were present, with granular and fibrilar deposits and collagen bundles. These alterations subsided by the 64th days. Macrophages seem to be the main immune effector cell in the C. callosus model of infection with T. cruzi. The mechanisms involved in the rapid fibrogenesis and its regression deserve further investigation

Studies on the experimental infection of Zygodontomys lasiurus (Rodentia-Cricetidae) with three strains of Trypanosoma cruzi

São apresentados resultados em relação a infecção expertmental de Zygodontomys lasiurus (Rodentia-Cricetidae) com duas cepas de T. cruzi isoladas de casos humanos, Y e Berenice, e uma isolada de um triatomíneo silvestre, chamada costalimai. Foram realizados estudos em relação a evolução da parasitemia, duração da patência e prepatência da infecção. Com o objetivo de verificar a agressividade e tropismo tissular das cepas de T. cruzi nesta espécie de roedor, foram também realizados estudos histopatológicos. Os resultados obtidos mostraram que os níveis de parasitemias foram baixos para as três cepas estudadas. A patência da infecção variou de 14 a 16 dias nos animais inoculados com a cepa Y, 26 a 29 dias com a Berenice e 9 a 13 dias com a costalimai. O período prepatente variou de 3 a 5 dias nos animais inoculados com a cepa Y, de 2 a 6 dias com a cepa Berenice e de 6 a 8 dias com a costalimai. As três cepas apresentaram em Z. lasiurus, comprometimento nitidamente muscular, provocando reações leves, moderadas e intensas.Studies on the experimental infection of Zygodontomys lasiurus (Rodentia-Cricetidae) are presented in the current paper. Three strains of T. cruzi were used in the experiments: two, Y and Berenice, were originated from human infection, while the third one was obtained from natural infection in a wild bug Triatoma costalimai. The evolution of the parasitemia was studied and the prepatent and patent periods determined. The tissular tropism and aggressiveness of the strains of T. cruzi were verified through histopathological studies. Results have shown that the parasitemia was always kept at low levels for all the strains. The prepatent period in the infected rodents varied from: 3 to 6 days in the Y strain; 2 to 6 days in the Berenice strain; 6 to 8 in the costalimai strain. The patent period showed the following duration patterns: 14 to 16 days in the Y strain; 26 to 29 in the Berenice strain and 6 to 8 days in the costalimai strain. Tissue damage was predominantly muscular, and the pathological reactions varied from slight to severe