LSHTM Research Online

Entamoeba histolytica infection may have various clinical manifestations. Nine out of ten E. histolytica infections remain asymptomatic, while the remainder become invasive and cause disease. The most common form of invasive infection is amebic diarrhea and colitis, whereas the most common extra-intestinal disease is amebic liver abscess. The underlying reasons for the different outcomes are unclear, but a recent study has shown that the parasite genotype is a contributor. To investigate this link further we have examined the genotypes of E. histolytica in stooland liver abscess-derived samples from the same patients. Analysis of all 18 paired samples (16 from Bangladesh, one from the United States of America, and one from Italy) revealed that the intestinal and liver abscess amebae are genetically distinct. The results suggest either that E. histolytica subpopulations in the same infection show varying organ tropism, or that a DNA reorganization event takes place prior to or during metastasis from intestine to liver. Citation: Ali IKM, Solaymani-Mohammadi S, Akhter J, Roy S, Gorrini C, et al. (2008) Tissue Invasion by Entamoeba histolytica: Evidence of Genetic Selection and/or DNA Reorganization Events in Organ Tropism. PLoS Negl Trop Dis 2(4): e219. doi:10.1371/journal.pntd.0000219 Editor: Anuradha Lohia, Bose Institute, India Received December 11, 2007; Accepted February 28, 2008; Published April 9, 2008 Copyright: 2008 Ali et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by the Wellcome Trust grant #067314 awarded to CGC, NIH grant AI 43596 awarded to WAP, and by the Ministry of University and Scientific Research grant FIL 2006 (Parma). Portions of this work formed part of the PhD thesis of IKMA, who was the recipient of Commonwealth Scholarship, UK, during 2001–2005 to pursue PhD studies at the London School of Hygiene & Tropical Medicine. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: W. A. Petri, Jr. received research support from TechLab, Inc. and royalties from a patent license agreement with TechLab for a diagnostic test for amebiasis. These royalties accrue to the American Society of Tropical Medicine and Hygiene without benefit to W. A. Petri, Jr. * E-mail: wap3g@virginia.edu (WAP); graham.clark@lshtm.ac.uk (CGC)