Experimental amoebic liver abcess produced by oral adminsitration of entamoeba histolytica cysts

To determine the possibility of amoebic invasion and liver abscess formation, Swiss albino mice were infected orally with E. Histolytica cysts isolated from human stools. Parasitological and histopathological changes in mice colon and liver tissues were sequentially followed. Three weeks post-infection [pi], 5% of immunocompetent and all cortisonized immunosuppressed mice passed the parasite in their stools. Only 70% of the latter group of mice sacrificed at that time developed invasive intestinal amoebiasis. At the end of the experiment, 100% of the remaining immunosuppressed animals developed the same intestinal pathology. Amoebic liver abscess was detected in 62.5% of them. Oral inoculation of E. histolytica cysts constituted an easy highly reproducible procedure for inducing liver abscess in immunosuppressed mice

Los modelos experimentales in vivo en la amibiasis / In vivo experimental models of amebiasis

La utilización de los modelos experimentales in vivo en la amibiasis, ha proporcionado información importante sobre los mecanismos involucrados en la relación huésped-parásito que determinan la producción de la enfermedad. En el laboratorio se han utilizado varios roedores para estudiar la amibiasis intestinal y la hepática. Para la primera, el modelo del "asa cecal lavada y cerrada" en el cobayo y el hámster ha sido útil para el análisis de las etapas tempranas del daño a la mucosa. También se ha logrado producir lesiones tempranas intestinales en el jerbo por inoculación intracecal de amibas en cultivo monoxénico. Para los modelos de amibiasis hepática, se han utilizado el hámster y el jerbo como animales susceptibles, y la rata y el cobayo como animales resistentes. El análisis morfológico de las lesiones hepáticas en losanimales susceptibles mostró que las células inflamatorias del huésped participan en la producción del daño hepático. La resistencia a la producción de absceso hepático amibiano en ratas y cobayos se debe en parte a los leucocitos polimorfonucleares en la rata y los macrófagos en el cobayo. La completa caracterización y estandarización de los diversos modelos de amibiasis en roedores constitutyen las bases para otros estudios biomédicos de importancia para el control de la enfermedad

Experimental amoebic meningoencephalitis: light microscopic and ultrastructure studies in mice

Heamorrhagic meningoencephalitis was found in the animals which died in 5-7 days post infection. The olfactory lobes and the base of the frontal lobes were congested and full of pus. Gray and white matter were both affected and were invaded with macrophages and leukocytes. Trophozoites were located between the neurons and adjacent to blood vessels. Ultrastructural study showed some amoebae with evidence of vigorous motility and feeding abilities. Erythrocytes and portions of myelin were seen within amoebae. The whole picture of the disease was similar to that observed in man which makes the mice an excellent model for further understanding of the disease