RESUMO
Entamoeba histolytica is a protozoan parasite that presents a risk to the health of millions of people worldwide. Due to the existence of different clinical forms caused by the parasite and also different virulence levels presented by one strain, one would expect differences in the profile of gene transcripts between virulent and nonvirulent cultures. In this study we used the differential display to select gene segments related to invasiveness of amoeba. One Brazilian strain of E. histolytica in two conditions, able or not to cause lesions in experimental animals, was used. RNA from this strain, was used to study the differential expression of genes. 29 specific gene fragments differentially expressed in the virulent strain were selected. By real-time PCR, six of these genes had confirmed their differential expression in the virulent culture. These genes may have important roles in triggering invasive amoebiasis and may be related to adaptation of trophozoites to difficulties encountered during colonization of the intestinal epithelium and liver tissue. Future studies with these genes may elucidate its actual role in tissue invasion by E. histolytica generating new pathways for diagnosis and treatment of amoebiasis.
Assuntos
Entamoeba histolytica/metabolismo , Entamebíase/metabolismo , Regulação da Expressão Gênica , RNA de Protozoário/biossíntese , Animais , Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidade , Entamebíase/genética , Entamebíase/terapia , Humanos , Camundongos , RNA de Protozoário/genética , RatosRESUMO
Genital amebiasis is a rare complication of infection with Entamoeba histolytica, even in areas where the pathogen is endemic. We describe a patient who apparently contracted intestinal amebiasis on a trip to Mexico and who presented with ulcerative vulvovaginitis 2 months later. Her condition rapidly progressed to severe necrotizing vulvovaginitis that required a radical vulvectomy. Histopathologic examination of the surgical specimen revealed the presence of E. histolytica trophozoites. The patient recovered after surgery and antiamebic therapy. We review the epidemiology and pathogenesis of genital amebiasis as well as therapy for this rare infection.
Assuntos
Entamebíase/etiologia , Viagem , Vulvovaginite/etiologia , Idoso , Animais , Entamoeba histolytica , Entamebíase/terapia , Feminino , Humanos , Iodoquinol/uso terapêutico , Metronidazol/uso terapêutico , México , Vulvovaginite/tratamento farmacológico , Vulvovaginite/parasitologia , Vulvovaginite/cirurgiaRESUMO
Invasive amebiasis caused by Entamoeba histolytica, and particularly amebic liver abscess, is a major public health problem in Mexico and some other countries because of the high incidence and mortality of this disease. This paper first discusses the pathogenic effect of E. histolytica and the defensive response of the host and then reports studies concerning the experimental induction of protective immunity to amebic infection. The pathogenic effect of E. histolytica is probably initiated by a lectin-mediated adhesion of trophozoites to target cells; the adhesion is followed by cytopathic activity and phagocytosis by the ameba. The defensive response is characterized by humoral and cellular immune reactions. Humoral immunity manifests itself by specific circulating antibodies useful in the diagnosis and seroepidemiology of amebiasis. Cellular immunity is shown by several characteristic reactions. Experimental induction of immunoprophylaxis with E. histolytica antigens represents the first stage in the development of a vaccine against E. histolytica for use in humans.
Assuntos
Amebíase/parasitologia , Entamoeba histolytica/patogenicidade , Entamebíase/parasitologia , Adolescente , Adulto , Animais , Formação de Anticorpos , Antígenos/administração & dosagem , Criança , Cricetinae , Entamoeba histolytica/imunologia , Entamebíase/epidemiologia , Entamebíase/imunologia , Entamebíase/terapia , Feminino , Humanos , Imunidade , Imunidade Celular , Imunoterapia , Abscesso Hepático Amebiano/epidemiologia , Abscesso Hepático Amebiano/terapia , Masculino , México , Distúrbios Nutricionais/complicações , Razão de Masculinidade , Testes Cutâneos , Vacinas/administração & dosagem , VirulênciaRESUMO
We present two successfully treated cases of amebic peritonitis. Acute peritonitis secondary to intra-abdominal rupture of an amebic liver abscess is an infrequent but serious complication of invasive amebiasis. Its diagnosis should be considered in anyone with a suspected liver abscess, jaundice, or diarrhea in whom peritonitis develops. This diagnosis should be further suggested in the United States if the patient is a male and is of Mexican origin in areas where this racial group constitutes the majority of cases of amebic disease. Use of radioisotope liver scans and the demonstration of serum precipitins to Endamoeba histolytica may provide rapid evidence of invasive disease, although surgical intervention is often necessary to make a specific diagnosis. Emetine hydrochloride alone or followed by metronidazole combined with surgical drainage is the current treatment for amebic peritonitis.