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Search Results: 1 - 10 of 97946 matches for " Ana Maria Jansen "
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Anothor Trypanosoma, distinct from T. cruzi, multiplies in the lumen of the anal glands the opossum Didelphis marsupialis
Deane, Maria P.;Jansen, Ana Maria;
Memórias do Instituto Oswaldo Cruz , 1986, DOI: 10.1590/S0074-02761986000100019
Abstract: epimastigotes were found multiplying in the anal glands and in hemocultures of an opossum; rare metacyclics were seen in the cultures. the flagellate is possibly t. (megatrypanum) freitasi rego, magalh?es & siqueira, 1957, but its final identification is still pending.
From a mono to a digenetic life-cycle: how was the jump for flagellates of the family trypanosomatidae?
Deane, Maria P.;Jansen, Ana M.;
Memórias do Instituto Oswaldo Cruz , 1988, DOI: 10.1590/S0074-02761988000300002
Abstract: it has been found that species of the digenetic genus trypanosoma as well as species of monogenetic trypanosomatids of insects can grow in the lumen of the scent glands of opossums reproducing the cycle they perform in the intestinal tract of their insect hosts. based on these findings, speculations are made on the incompletely known cycles of many mammalian trypanosomes and on the evolution of the family trypanosomatidae.
Trypanosoma cruzi: vertebrate and invertebrate cycles in the same mammal host, the opossum Didelphis marsupialis
Deane, Maria P.;Lenzi, Henrique L.;Jansen, Ana;
Memórias do Instituto Oswaldo Cruz , 1984, DOI: 10.1590/S0074-02761984000400021
Abstract: epimastigotes multiplying extracellularly and metacyclic trypomastigotes, stages that correspond to the cycle of trypanosoma cruzi in the intestinal lumen of its insect vector, were consistently found in the lumen of the anal glands of opossums didelphis marsupialis inoculated subcutaneously with infective feces of triatomid bugs.
Trypanosoma cruzi infection in the opossum Didelphis marsupialis: absence of neonatal transmission and protection by maternal antibodies in experimental infections
Jansen, Ana M.;Madeira, Fatima B.;Deane, Maria P.;
Memórias do Instituto Oswaldo Cruz , 1994, DOI: 10.1590/S0074-02761994000100008
Abstract: the high rate of natural trypanosoma cruzi infection found in opossums does not always correlate with appreciable densities of local triatomid populations. one alternative method which might bypass the invertebrate vector is direct transmission from mother to offspring. this possibility was investigated in five t. cruzi infected females and their litters (24 young). the influence of maternal antibodies transferred via lactation, on the course of experimental infection, was also examined. our results show that neonatal transmission is probably not responsible for the high rate of natural t. cruzi infection among opossums. in addition antibodies of maternal origin confer a partial protection to the young. this was demonstrated by the finding of a double prepatency period and 4,5 fold lower levels of circulating parasites, in experimentally infected pouch young from infected as compared to control uninfected mothes. on the other hand, the duration of patent parasitemia was twice as long as that observed in the control group.
Infection of a mammal by monogenetic insect trypanosomatids (Kinetoplastida, trypanosomatidae)
Jansen, Ana M.;Carreira, Jo?o C.;Deane, Maria P.;
Memórias do Instituto Oswaldo Cruz , 1988, DOI: 10.1590/S0074-02761988000300001
Abstract: monogenetic insect trypanosomatids of the genera crithidia, leptomonas and herpetomonas, multiplied as in axenic cultures, for many months, in the lumen of the scent glands of the opossum didelphis marsupialis. specific antibodies were detected in the serum of the animals but there was no evidence of invasion of their tissues by the parasites.
Enfoques conceptuales y propuestas metodológicas para el estudio de las interacciones entre el medio ambiente y la salud: aplicación a un programa de investigación sobre la tripanosomiasis americana
Roma?a, Cristina;Emperaire, Laure;Jansen, Ana Maria;
Cadernos de Saúde Pública , 2003, DOI: 10.1590/S0102-311X2003000400017
Abstract: modifications of the landscape by human activity and migratory movements contribute to the emergence or reemergence of zoonotic and human diseases, particularly those transmitted by insects which often escape the changing environmental conditions, adapting and modifying their trophic networks and morphology, including their genotype. a better understanding of relationships between ecological factors, human factors, and anthropozoonoses is vital to be able to identify variables that allow one to map the risk for human populations. this is the main objective of the research program landscape ecology, land-use dynamics, and eco-pathogenic complexes: eco-epidemiologic risk in the case of american trypanosomiasis, developed in various brazilian ecosystems. the authors describe the program's conceptual and methodological basis and highlight the role of eco-epidemiology for studying the structure and function of natural and anthropogenic foci of infection. modeling spatial and temporal dynamics can help predict and monitor such tropical diseases.
Enfoques conceptuales y propuestas metodológicas para el estudio de las interacciones entre el medio ambiente y la salud: aplicación a un programa de investigación sobre la tripanosomiasis americana
Roma?a Cristina,Emperaire Laure,Jansen Ana Maria
Cadernos de Saúde Pública , 2003,
Abstract: Las modificaciones del paisaje causadas por las actividades y migraciones humanas contribuyen en hacer emerger o re-emerger enfermedades tropicales, particularmente aquellas cuya transmisión se realiza por insectos vectores que a menudo deben escapar a las condiciones cambiantes ambientales, adaptándose y modificando sus redes tróficas, su morfología, hasta su genotipo. Obtener una mejor comprensión de las relaciones entre los factores ecológicos y humanos y las antropozoonosis es vital para poder identificar variables que permitan cartografiar el riesgo para las poblaciones humanas. Este es el objetivo del programa de investigación Ecología del Paisaje, Dinámica de los Agro-Ecosistemas y Complejos Eco-Patógenos: La Definición del Riesgo Eco-Epidemiológico en la Tripanosomiasis Americana que se desarrolla en diferentes ecosistemas del Brasil. Los autores describen las bases conceptuales y metodológicas del programa e insisten sobre el rol del método eco-epidemiológico para el estudio de la estructura y el funcionamiento de los focos naturales y antropizados de la infección. Modelizar su dinámica espacial y temporal permite concebir nuevos útiles de predicción y de vigilancia.
The sylvatic cycle of Trypanosoma cruzi: a still unsolved puzzle
Jansen Ana Maria,Pinho Ana Paula Santos de,Lisboa Cristiane Varella,Cupolillo Elisa
Memórias do Instituto Oswaldo Cruz , 1999,
Histopathological study of experimental and natural infections by Trypanosoma cruzi in Didelphis marsupialis
Carreira, Jo?o Carlos Araujo;Jansen, Ana Maria;Deane, Maria P;Lenzi, Henrique Leonel;
Memórias do Instituto Oswaldo Cruz , 1996, DOI: 10.1590/S0074-02761996000500012
Abstract: didelphis marsupialis, the most important sylvatic reservoir of trypanosoma cruzi, can also maintain in their anal scent glands the multiplicative forms only described in the intestinal tract of triatomine bugs. a study of 21 experimentally and 10 naturally infected opossums with t. cruzi was undertaken in order to establish the histopathological pattern under different conditions. our results showed that the inflammation was predominantly lymphomacrophagic and more severe in the naturally infected animals but never as intense as those described in chagas' disease or in other animal models. the parasitism in both groups was always mild with very scarce amastigote nests in the tissues. in the experimentally infected animals, the inflammation was directly related to the presence of amastigotes nests. four 24 days-old animals, still in embryonic stage, showed multiple amastigotes nests and moderate inflammatory reactions, but even so they survived longer and presented less severe lesions than experimentally infected adult mice. parasites were found in smooth, cardiac and/or predominantly striated muscles, as well as in nerve cells. differing from the experimentally infected opossums parasitism in the naturally infected animals predominated in the heart, esophagus and stomach. parasitism of the scent glands did not affect the histopathological pattern observed in extraglandular tissues.
Humoral Immune Response Kinetics in Philander opossum and Didelphis marsupialis Infected and Immunized by Trypanosoma cruzi Employing an Immunofluorescence Antibody Test
Legey, Ana Paula;Pinho, Ana Paula S;Xavier, Samanta C Chagas;Leon, Leonor L;Jansen, Ana Maria;
Memórias do Instituto Oswaldo Cruz , 1999, DOI: 10.1590/S0074-02761999000300016
Abstract: philander opossum and didelphis marsupialis considered the most ancient mammals and an evolutionary success, maintain parasitism by trypanosoma cruzi without developing any apparent disease or important tissue lesion. in order to elucidate this well-balanced interaction, we decided to compare the humoral immune response kinetics of the two didelphids naturally and experimentally infected with t. cruzi and immunized by different schedules of parasite antigens, employing an indirect fluorescence antibody test (ifat). both didelphids responded with high serological titers to different immunization routes, while the earliest response occurred with the intradermic route. serological titers of naturally infected p. opossum showed a significant individual variation, while those of d. marsupialis remained stable during the entire follow-up period. the serological titers of the experimentally infected animals varied according to the inoculated strain. our data suggest that (1) ifat was sensitive for follow-up of p. opossum in natural and experimental t. cruzi infections; (2) both p. opossum and d. marsupialis are able to mount an efficient humoral immune response as compared to placental mammals; (3) experimentally infected p. opossum and d. marsupialis present distinct patterns of infection, depending on the subpopulation of t. cruzi, (4) the differences observed in the humoral immune responses between p. opossum and d. marsupialis, probably, reflect distinct strategies selected by these animals during their coevolution with t. cruzi.
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