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Pathogenicity of Acanthamoeba.

Page updated 26/5/02

Acanthamoeba is essentially ubiquitous in the biosphere inhabiting every conceivable space from the Antarctic to the Artic.  Naturally, man and Acanthamoeba often cross paths.  In the vast majority of cases there is no conflict, but two factors have lead to problems over the last twenty years; AIDs and contact lenses.  Immunocompromisation as a result of AIDs infection has lead to many secondary Acanthamoeba infections, and contact lens wearers are at risk from Acanthamoeba keratitis.


In a very small number of instances otherwise healthy individuals have been known to succumb to infection by Acanthamoeba. This disease is known as granulatomatous amoebic encephalitis (GAE) or primary amoebic meningoencephalitis (PAM) (Butt, 1966).  Immunity against Acanthamoeba is probably through macrophages (Marciano-Cabral & Toney, 1998), or natural killer cells (Hyun et al, 1992; Kim et al, 1993) although immunization by the administering of Acanthamoeba extract prior to challenge with the sane species of intact Acanthamoeba resulted in a degree of protection (in mice) indicating that an antibody response may also be involved (Ferrante, 1991b).  There is also the suggestion that mice pups may be afforded protection through immunization of their mothers (Kong et al, 1993).

Acanthamoeba cysts have been discovered in human faeces (Zaman et al, 1998), however, there has to date to my knowledge been no indication of the involvement of the amoeba in pathogenesis in the intestinal tract as there is of course with Entamoeba.

Very few Acanthamoeba in the natural environment turn out to be pathogenic to humans. The differentiation between pathogenic and non-pathogenic Acanthamoeba is an important activity but is clouded by the fact that mice seem especially prone to becoming infected with Acanthamoeba.  Many attempts have been made to find "the" difference between the two, and several predisposing properties have been identified for example the ability to grow at temperatures approaching mammalian body has been reported to be important.  Other less obvious characteristics have been suggested including some possibly spurious genetic markers (Howe et al, 1997).  The classification of Acanthamoeba has been problematic relying on morphological features especially of the cysts.  However, not only has the cyst morphology been found to be a function (to some extent) of the conditions under which the amoeba encyst (), but this classification scheme has not been found to reliably reflect possibly more robust genetic efforts based on SSUrDNA sequence analysis (Stothard et al).  See Acanthamoeba Classification.

Acanthamoeba Proteases in Pathogenesis Acanthamoeba keratitis Acanthamoeba and AIDS
  Acanthamoeba and Pathogenic Bacteria Acanthamoeba induced apoptosis in vertebrate cells

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Simon Kilvington


Borazjani, R. N., May, L. L., Noble, J. A., Avery, S. V. & Ahearn, D. G. (2000) Flow cytometry for determination of the efficacy of contact lens disinfecting solutions against Acanthamoeba spp.  App.Environ.Microbiol. 66, 1057-1061.

Butt, C.G. (1966) Primary amebic meningoencephalitis. New England J.Med. 274, 1473-1476.

Cao, Z., Jefferson, D. M. & Panjwani, N. (1998) Role of carbohydrate-mediated adherence in cytopathogenic mechanisms of AcanthamoebaJ.Biol.Chem. 273, 15838-15845.

Dini, L. A., Cockinos, C., Frean, J. A., Niszl, I. A. & Markus, M. B. (2000) Unusual case of Acanthamoeba polyphaga and Pseudomonas aeruginosa keratitis in a contact lens wearer from Gauteng, South Africa.  J.Clin.Microbiol. 38, 826-829.

Dove Pettit, D. A., Williamson, J., Cabral, G. A. & Marciano-Cabral, F. (1996) In vitro destruction of nerve cell cultures by Acanthamoeba spp.: A transmission and scanning electron microscopic study. J.Parasitol. 82, 769-777.

Ferrante, A. (1991a) Free-living amoeba: pathogenicity and immunity. Parasite Immunology. 13, 31-47.

Ferrante, A. (1991b) Immunity to Acanthamoeba. Rev.Infect.Diseases. 13, 403-409.

Fritsche, T. R., Sobek, D. & Gautom, R. K. (1998) Enhancement of in vitro cytopathogenicity by Acanthamoeba spp. following acquisition of bacterial endosymbionts. FEMS letters. 166, 231-236.

Fritsche, T. R., Gautom, R. K., Seyedirashti, S., Bergeron, D. L. & Lindquist, T. D. (1993) Occurence of bacterial endosymbionts in Acanthamoeba spp. isolated from corneal and environmental specimens and contact lenses. J.Clin.Microbiol. 31, 1122-1126.

Howe, D. K., Vodkin, M. H., Novak, R. J., Visvesvara, G. & McLaughlin, G. L. (1997) Identification of two genetic markers that distinquish pathogenic and nonpathogenic strains of Acanthamoeba spp., Parasitol.Res. 83, 345-348.

Hurt, M., Proy, V., JY, N. & Alizadeh, H. (2003) The interaction of Acanthamoeba castellanii cysts with macrophages and neutrophils. J.Parasitol. 89, 565-572.

Hyun, D.-K., Shin, C.-O. & Im, K.-I. (1992) Natural killer cell activity in mice infected with Acanthamoeba culbertsoniKorean J. Parasitol. 29, 101-112.

Im, K.-i., Shin, H.-J., Seo, D. W., Jeon, S.-H. & Kim, T.-E. (1999) Pathogenicity of Korean isolates of Acanthamoeba by observing the experimental infection and zymodemes of five enzymes. Korean J. Parasitol. 37, 85-92.

Kim, T.-U., Im, K.-I. & Cho, Y.-D. (1989) A biochemical study on the cytolytic substance of Acanthamoeba culbertsoni. Yonsei Rep.Trop.Med. 20, 32-36.

Kong, H.-H., Seo, S.-A., Shin, C.-O. & Im, K.-I. (1993) The effect of active immunization with Acanthamoeba culbertsoni. K.J.Parasitol. 31, 157-163.

Ledee, D. R., Seal, D. V. & Byers, T. J. (1998) Confirmatory evidence from 18S rRNA gene analysis for in vivo development of prpamidine resistance in a temporal series of Acanthamoeba isolates from a patient.  Antimicrob.Agents Chemother. 42, 2144-2145.

Leher, H., Kinoshita, K., Alizadeh, H., Zaragoza, F. L., He, Y.-G. & Niederkorn, J. (1998) Impact of oral immunization with Acanthamoeba antigens on parasite adhesion and corneal infection. IOVS. 39, 2337-2343.

Leher, H., Silvany, R., Alizadeh, H., Huang, J. & Niederkorn, J. Y. (1998) Mannose induces the release of cytopathogenic factors from Acanthamoeba castellanii. Infection Immunity. 66, 5-10.

Lehmann, O. J., Green, S. M., Morlet, N., Kilvington, S., Keys, M. F., Matheson, M. M., Dart, J. K. G., McGill, J. I. & Watt, P. J. (1998) Polymerase chain reaction analysis of corneal epithelial and tear samples in the diagnosis of Acanthamoeba keratitis., IOVS. 39, 1261-1265.

Macrciano-Cabral, F., Puffenbarger, R. & Cabral, G. A. (2000) The increasing importance of Acanthamoeba infections. J.Eukaryot.Microbiol. 47, 29-36.

Martinez, A. J. (1991) Infection of the central nervous system due to Acanthamoeba. Rev.Infect.Diseases. 13, 399-402.

Mazur, T., Hadás, E., Gustowska, L., Winiecka-Krusnell, J. & Linder, E. (1999) Secondary amoebic infections in mice due to Acanthamoeba sp. Parasitol.Res. 85, 776-778.

Morton, L. D., McLaughlin, G. L. & Whiteley, H. E. (1991) Effects of temperature, amebic strain, and carbohydrates on Acanthamoeba adherence to corneal epithelium in vitro. Infect.Immun. 59, 3819-3822.

Migueles, S. & Kumar, P. (1998) Primary cutaneous Acanthamoeba infection in a patient with AIDS. Clin.Infect.Disease. 27, 1547-1548.

Niederkorn, J. Y., Alizadeh, H., Leher, H. & McCulley, J. P. (1999) The pathogenesis of Acanthamoeba keratitis., Microbes & Infection. 1, 437-443.

Niszl, I. A., Veale, R. B. & Markus, M. B. (1998) Cytophathogenicity of clinical and environmental Acanthamoeba isolates for two mammalian cell lines. J.Parasitol. 84, 961-967.

Rohr, U., Weber, S., Michel, R., Selenka, F. & Wilhelm, M. (1998) Comparison of free-living amoebae in hot water systems of hospitals with isolates from moist sanitary areas by identifying genera and determining temperature tolerance. App.Environ.Microbiol. 64, 1822-1824.

Schuster, F. L. & Visversvara, G. S. (1998) Efficacy of novel antimicrobials against clinical isolates of opportunistic amebas. J.Euk.Microbiol. 45, 612-618.

Segal, G. & Shuman, H. A. (1999) Legionella pneumophila utilizes the same genes to multiply within Acanthamoeba castellanii and human macrophages. Infect.Immun. 67, 2117-2124.

Taylor, W. M., Pidherney, M. S., Alizadeh, H. & Niederkorn, J. Y. (1995) In vitro characterization of Acanthamoeba castellanii cytopathic effect.  J.Parasitol. 81, 603-609.

Toney, D. M. & Marciano-Cabral, F. (1998) Resistance of Acanthamoeba species to complement lysis. J.Parasitol. 84, 338-344.

Visvesvara, G. S., Mirra, S. S., Brandt, F. H., Moss, D. M., Mathews, H. M. & Martinez, A. J. (1983) Isolation of two strains of Acanthamoeba castellanii from human tissue and their pathogenicity and isoenzyme profiles. J.Clin.Microbiol. 18, 1405-1412.

Wilhelmus, K. R. (1991) Introduction: The increasing importance of Acanthamoeba. Rev.Infect.Diseases. 13, 367-368.

Zaman, V., Zaki, M. & Manzoor, M. (1998) Acanthamoeba in human faeces from Karachi. Annals Trop.Med.&Parasitol. 93, 189-191.

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