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Interdisciplinary Perspectives on Infectious Diseases
Volume 2009, Article ID 251406, 14 pages
Review Article

Diagnosis of Infections Caused by Pathogenic Free-Living Amoebae

1Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
2Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA

Received 25 March 2009; Accepted 5 June 2009

Academic Editor: Louis M. Weiss

Copyright © 2009 Bruno da Rocha-Azevedo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Naegleria fowleri, Acanthamoeba spp., Balamuthia mandrillaris, and Sappinia sp. are pathogenic free-living amoebae. N. fowleri causes Primary Amoebic Meningoencephalitis, a rapidly fatal disease of the central nervous system, while Acanthamoeba spp. and B. mandrillaris cause chronic granulomatous encephalitis. Acanthamoeba spp. also can cause cutaneous lesions and Amoebic Keratitis, a sight-threatening infection of the cornea that is associated with contact lens use or corneal trauma. Sappinia pedata has been identified as the cause of a nonlethal case of amoebic encephalitis. In view of the potential health consequences due to infection with these amoebae, rapid diagnosis is critical for early treatment. Microscopic examination and culture of biopsy specimens, cerebral spinal fluid (CSF), and corneal scrapings have been used in the clinical laboratory. For amoebic keratitis, confocal microscopy has been used to successfully identify amoebae in corneal tissue. More recently, conventional and real-time PCR assays have been developed that are sensitive and specific for the amoebae. In addition, multiplex PCR assays are available for the rapid identification of these pathogens in biopsy tissue, CSF, and corneal specimens.