Is Entamoeba histolytica REALLY HISTOLYTIC?
Human and experimental lesions caused by Entamoeba histolytica are characterized by extensive tissue destruction. Such feature justified the name given to the parasite by Fritz Schaudin in 1905. Earlier studies suggested the presence of a “toxin” in the parasite, but no progress was made in the characterization of the molecular basis of tissue necrosis in amebiasis until E. histolytica was axenically cultured by Diamond et al in 1978. Since that time a number of factors have been suggested as responsible for the pathogenicity of E. histolytica, such as motility, phagocytosis, amoebopore, phospholipase A, cysteine proteases, adhesins, and other molecules. A brief survey of the evidence supporting such claims suggests that the mechanism(s) of tissue damage in amebiasis may be more complicated. Several studies in our laboratory using experimental acute amebic liver absceso in hamsters indicate that the host plays an important role in tissue damage and that many of the so-called “virulence
