This study has been done to evaluate the central nervous system (CNS) of mice infected with Trypanosoma cruzi and its relationships with the irreversible decrease of motor activity of the rear limbs during acute Chagas´disease. The course of the present study shows the in vivo behaviour of three parasites strains which were isolated from different sources and geographical areas, with the purpose of explaining the parasitemia, mortality rate, clinical, pathological and histopathological changes in the CNS of infected mice. The mice were injected intraperitoneally with 5.10 3 bloodstreams of different T. cruzi strains. The mice infected with PR and ASM strains from Venezuela, showed low parasitemia and high mortality, while the Y strain produced higher parasitemia levels. At the 30th day post-infection both left parietal brain cortex (LPC) and spinal cord (SC) were sectioned, stained with hematoxilin and eosin (H-E) and examined by means of confocal ligth microscopy. At this time, the pathology of the CNS exhibited focal infiltrates of monocytes, lymphocytes, plasmocytes, polymorphonuclear cells and loss of neuronas and motoneurons. The sections of LPC of infected mice with ASM strain, showed loss neuronal, parasites and abundant T. cruzi antigen deposits in the proximity of the swollen neurons. The sections of SC stained with Enolase-Avidin-Biotin-Peroxidase showed a reduction in the average number of neurons of the cervical region (CR) of the infected mice with PR, ASM and Y strains. Sections stained with Propidium Ioduro (IP) showed a reduction of the number of motoneurons in all regions of the SC, with a significant difference between groups infected with different T. cruzi strains and control uninfected mice (P < 0.05). This study established a correlation between the parasitism in the proximity to inflammatory cells, together the appearance of T. cruzi antigen and neuronal destruction in the brain. Therefore it can be concluded that the changes in CNS may be attributed to early parasitism in nervous tissue, which occur in a few days, involving clinico-pathological manifestations, which produced alterations of the mobility with paralysis of the rear limbs and death in 100% of mice with acute infection produced by PR and ASM-T. cruzi strains from Venezuela.
Se presenta una sinopsis del género Rhytidometopum Hebard, 1920, con la descripción de una nueva especie para Venezuela, que constituye la segunda para el país y la cuarta para el género. Los caracteres de mayor importancia taxonómica son debidamente descritos e ilustrados. Se provee una clave bilingüe para la identificación de las especies. Adicionalmente se incorporan dos registros de especies de cucarachas venezolanas omitidos en una contribución previa del grupo.
Introducción. Belminus ferroae es un triatomino de comportamiento entomófago, sin embargo, puede alimentarse de vertebrados ocasionalmente. No se ha demostrado infección natural por Trypanosoma cruzi en esta especie, como tampoco la metaciclogénesis del parásito.Objetivo. Examinar la metaciclogénesis de T. cruzi en B. ferroae y la capacidad infectiva de las heces o sus contenidos intestinales en roedores.Materiales y métodos. Se analizaron las heces y la orina expulsadas espontáneamente por los insectos o mediante compresión abdominal o extracción del contenido intestinal a los 10, 20, 30, 40, 50 y 60 días. Se cuantificó la carga parasitaria de T. cruzi y sus formas evolutivas se identificaron con tinción de Giemsa. Asimismo, se evaluó en ratones albinos la apacidad infectiva de los tripomastigotes metacíclicos de T. cruzi obtenidos de las heces o contenidos intestinales de los especímenes infectados.Resultados. El análisis parasitológico reveló tres (15 %) insectos infectados con T. cruzi a los 30 (n=1), 40 (n=1) y 50 (n=1) días después de la infección con cargas parasitarias de hasta 1,62 x 105 tripanosomas/mm3 y porcentajes de metaciclogénesis entre el 3,5 y el 6,78 %. Conclusiones. Se demuestra por primera vez, en una especie del género Belminus, la metaciclogenésis de T. cruzi en condiciones de laboratorio y la capacidad infectiva de las heces para un huésped vertebrado.
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