RESUMO
In Mexico, like in other countries, there is an special interest for amebiasis because it represents a Public health problem; there are about 5 million people that in some time of their lives had tissue invasion by this parasite. 1-2% of mexicanas have intestinal amebiasis and probably there are 850,000 to 1,700,000 carriers of entamoeba cysts. 6% of the general population have circulating antiameba antibodies. In 1988 we studied the amebic hepatic abscess seen in the hospitals of the Instituto Mexicano del Seguro Social in the Valley of Mexico. During that year there were 396 patients with such illness (0.19% of hospital admissions) with a 1.01% mortality. Comparing this data with reports of 1969 there was a reduction in the number of patients and deaths. Also amebiasis has decreased in autopsy studies. However, we have not found recent variations in the clinical behavior of amebiasis. Advances in diagnostic methods and more liberal use of metronidazole have reduced the number of severely ill patients.
Assuntos
Amebíase/patologia , Entamebíase/patologia , Animais , Estudos Transversais , Disenteria Amebiana/complicações , Disenteria Amebiana/epidemiologia , Disenteria Amebiana/patologia , Entamoeba histolytica/patogenicidade , Entamebíase/epidemiologia , Humanos , Abscesso Hepático Amebiano/epidemiologia , Abscesso Hepático Amebiano/patologia , México/epidemiologia , VirulênciaAssuntos
Pólipos do Colo/diagnóstico , Pólipos Intestinais/diagnóstico , Neoplasias Retais/diagnóstico , Pólipos do Colo/etiologia , Pólipos do Colo/cirurgia , Feminino , Humanos , Pólipos Intestinais/etiologia , Pólipos Intestinais/cirurgia , Masculino , Estudos Prospectivos , Neoplasias Retais/etiologia , Neoplasias Retais/cirurgiaRESUMO
The production of cecal lesions with axenically cultivated Entamoeba histolytica in an experimental animal is reported for the first time. Forty-three newborn guinea pigs (one to five days old) were inoculated via laparatomy with 2.5 x 10(5) to 2 x 10(6) strain HM-1-IMSS amebae. Of 23 animals surviving to the 7th postinoculation day all showed cecal lesions at necropsy regardless of the age of the animal when used or the number of amebae received. Ten animals had lesions visible to the unaided eye and 13 had only microscopic lesions. No lesions were noted in other organs of the abdominal or thoracic regiosn. The use of axenically cultivated ameabae in newborn guinea pigs should prove a useful experimental model for the study of amebiasis.
Assuntos
Disenteria Amebiana/parasitologia , Entamoeba histolytica/patogenicidade , Animais , Animais Recém-Nascidos , Ceco/parasitologia , Ceco/patologia , Modelos Animais de Doenças , Disenteria Amebiana/patologia , CobaiasRESUMO
Animal models have been utilized to study experimentally produced intestinal amebiasis. The guinea pig has been the animal of choice to study the mechanisms by which trophozoites of E. histolytica produce colonic lesions. The purpose of this study was to produce lesions in the colon of newborn guinea pigs by the injection of E. histolytica, HM-1 IMSS, strain grown axenically, and to characterize the early changes with the light and electron microscopes. A total of 35 guinea pigs, one to two days old, were inoculated into the cecum with one and a half million of trophozoites of E. histolytica. Thirteen surviving animals were sacrificed. In four there were clear cut amebic lesions. Sections were taken from neighbouring transitional zones. The most important changes were the migrations of trophozoites to the bottom of colonic glands with many parasites located within the crypts. There was passage of ameabae to the lamina propia with practically no inflammatory reaction. It is thought that the parasite, in contact with epithelial crypt cell, produce direct lysis of these elements leading to migration of amebae into the lamina propia.
Assuntos
Colo/parasitologia , Entamoeba histolytica/patogenicidade , Mucosa Intestinal/patologia , Animais , Colo/patologia , Disenteria Amebiana/parasitologia , Disenteria Amebiana/patologia , Entamoeba histolytica/crescimento & desenvolvimento , CobaiasRESUMO
In eight guinea pigs, trophozoites of E. histolytica HM-2 IMSS strain grown in plurixenic conditions were inoculated in their cecum. Two died two days after inoculation; the remaining si- were sacrificed six days afterwards. Tissue samples were obtained from amebic lesions and nearby areas. At ultramicroscopic level it was observed that epithelial cells in contact with the parasite had short and/or scanty microvilli, swollen mitochondria, ER dilatation and absence of the terminal bar. When trophozoite was within the epithelium, cells in contact with it were destroyed; basement membrane was elongated before it was broken up by the parasite. In the lamina propria trophozoites were found close to glands, blood capillaries and in contact with macrophages, lymphocytes, and most cells. No polymorphonuclear cells were identified in all samples studied. Capillaries were congestive, lacking polymorphonuclear cells. It was postulated that probably initial colonic mucosa lesion in amebiasis depends solely upon parasite action.