Following ingestion, what is the life cycle of Entamoeba histolytica?

Answer

Ingestion of E histolytica cysts (see the first image below) from the environment is followed by excystation in the terminal ileum or colon to form highly motile trophozoites (see the second image below). Upon colonization of the colonic mucosa, the trophozoite may encyst and is then excreted in the feces, or it may invade the intestinal mucosal barrier and gain access to the bloodstream, whereby it is disseminated to the liver, lung, and other sites. Excreted cysts reach the environment to complete the cycle.

Entamoeba histolytica cyst. Image courtesy of Centers for Disease Control and Prevention.

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Entamoeba histolytica trophozoite. Image courtesy of Centers for Disease Control and Prevention.

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Disease may be caused by only a small number of cysts, but the processes of encystation and excystation are poorly understood. The adherence of trophozoites to colonic epithelial cells seems to be mediated by a galactose/N -acetylgalactosamine (GAL/GalNAc)–specific lectin,^{[4, 6, 7]}a 260-kd surface protein containing a 170-kd subunit and a 35-kd subunit. A mucosal immunoglobulin A (IgA) response against this lectin can result in fewer recurrent infections.^[8]

Both lytic and apoptotic pathways have been described. Cytolysis can be undertaken by amebapores, a family of peptides capable of forming pores in lipid bilayers.^[4]Furthermore, in animal models of liver abscess, trophozoites induced apoptosis via a non-Fas and non–tumor necrosis factor (TNF)-α1 receptor pathway.^[9]The amebapores, at sublytic concentrations, can also induce apoptosis.

Cysteine proteinases have been directly implicated in invasion and inflammation of the gut and may amplify interleukin (IL)-1–mediated inflammation by mimicking the action of human IL-1–converting enzyme, cleaving IL-1 precursor to its active form.^{[4, 10]}The cysteine proteinases can also cleave and inactivate the anaphylatoxins C3a and C5a, as well as IgA and immunoglobulin G (IgG).^{[11, 12]}

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Pritt BS, Clark CG. Amebiasis. Mayo Clin Proc. 2008 Oct. 83(10):1154-9; quiz 1159-60. [Medline].
Grecu F, Bulgariu T, Blanaru O, Dragomir C, Lunca C, Stratan I, et al. Invasive amebiasis. Chirurgia (Bucur). 2006 Sep-Oct. 101(5):539-42. [Medline].
Haque R, Huston CD, Hughes M, Houpt E, Petri WA Jr. Amebiasis. N Engl J Med. 2003 Apr 17. 348(16):1565-73. [Medline].
Stanley SL Jr. Amoebiasis. Lancet. 2003 Mar 22. 361(9362):1025-34. [Medline].
Shirley DT, Farr L, Watanabe K, Moonah S. A Review of the Global Burden, New Diagnostics, and Current Therapeutics for Amebiasis. Open Forum Infect Dis. 2018 Jul. 5 (7):ofy161. [Medline].
Ravdin JI, Stanley P, Murphy CF, Petri WA Jr. Characterization of cell surface carbohydrate receptors for Entamoeba histolytica adherence lectin. Infect Immun. 1989 Jul. 57(7):2179-86. [Medline]. [Full Text].
Ximénez C, Cerritos R, Rojas L, Dolabella S, Morán P, Shibayama M, et al. Human amebiasis: breaking the paradigm?. Int J Environ Res Public Health. 2010 Mar. 7(3):1105-20. [Medline]. [Full Text].
Haque R, Mondal D, Duggal P, Kabir M, Roy S, Farr BM, et al. Entamoeba histolytica infection in children and protection from subsequent amebiasis. Infect Immun. 2006 Feb. 74(2):904-9. [Medline]. [Full Text].
Seydel KB, Stanley SL Jr. Entamoeba histolytica induces host cell death in amebic liver abscess by a non-Fas-dependent, non-tumor necrosis factor alpha-dependent pathway of apoptosis. Infect Immun. 1998 Jun. 66(6):2980-3. [Medline]. [Full Text].
Que X, Reed SL. Cysteine proteinases and the pathogenesis of amebiasis. Clin Microbiol Rev. 2000 Apr. 13(2):196-206. [Medline]. [Full Text].
Kelsall BL, Ravdin JI. Degradation of human IgA by Entamoeba histolytica. J Infect Dis. 1993 Nov. 168(5):1319-22. [Medline].
Reed SL, Keene WE, McKerrow JH, Gigli I. Cleavage of C3 by a neutral cysteine proteinase of Entamoeba histolytica. J Immunol. 1989 Jul 1. 143(1):189-95. [Medline].
Abhyankar MM, Shrimal S, Gilchrist CA, Bhattacharya A, Petri WA Jr. The Entamoeba histolytica serum-inducible transmembrane kinase EhTMKB1-9 is involved in intestinal amebiasis. Int J Parasitol Drugs Drug Resist. 2012 Dec. 2:243-248. [Medline]. [Full Text].
Seydel KB, Li E, Swanson PE, Stanley SL Jr. Human intestinal epithelial cells produce proinflammatory cytokines in response to infection in a SCID mouse-human intestinal xenograft model of amebiasis. Infect Immun. 1997 May. 65(5):1631-9. [Medline]. [Full Text].
Stenson WF, Zhang Z, Riehl T, Stanley SL Jr. Amebic infection in the human colon induces cyclooxygenase-2. Infect Immun. 2001 May. 69(5):3382-8. [Medline]. [Full Text].
Braga LL, Ninomiya H, McCoy JJ, Eacker S, Wiedmer T, Pham C, et al. Inhibition of the complement membrane attack complex by the galactose-specific adhesion of Entamoeba histolytica. J Clin Invest. 1992 Sep. 90(3):1131-7. [Medline]. [Full Text].
Fotedar R, Stark D, Beebe N, Marriott D, Ellis J, Harkness J. Laboratory diagnostic techniques for Entamoeba species. Clin Microbiol Rev. 2007 Jul. 20(3):511-32, table of contents. [Medline]. [Full Text].
Shimokawa C, Kabir M, Taniuchi M, Mondal D, Kobayashi S, Ali IK, et al. Entamoeba moshkovskii is associated with diarrhea in infants and causes diarrhea and colitis in mice. J Infect Dis. 2012 Sep 1. 206 (5):744-51. [Medline].
Verkerke HP, Petri WA Jr, Marie CS. The dynamic interdependence of amebiasis, innate immunity, and undernutrition. Semin Immunopathol. 2012 Nov. 34(6):771-85. [Medline]. [Full Text].
Swaminathan A, Torresi J, Schlagenhauf P, Thursky K, Wilder-Smith A, Connor BA, et al. A global study of pathogens and host risk factors associated with infectious gastrointestinal disease in returned international travellers. J Infect. 2009 Jul. 59 (1):19-27. [Medline].
Gunther J, Shafir S, Bristow B, Sorvillo F. Short report: Amebiasis-related mortality among United States residents, 1990-2007. Am J Trop Med Hyg. 2011 Dec. 85 (6):1038-40. [Medline].
Gunther J, Shafir S, Bristow B, Sorvillo F. Short report: Amebiasis-related mortality among United States residents, 1990-2007. Am J Trop Med Hyg. 2011 Dec. 85(6):1038-40. [Medline]. [Full Text].
Valenzuela O, Morán P, Gómez A, Cordova K, Corrales N, Cardoza J, et al. Epidemiology of amoebic liver abscess in Mexico: the case of Sonora. Ann Trop Med Parasitol. 2007 Sep. 101(6):533-8. [Medline].
van Hal SJ, Stark DJ, Fotedar R, Marriott D, Ellis JT, Harkness JL. Amoebiasis: current status in Australia. Med J Aust. 2007 Apr 16. 186(8):412-6. [Medline].
Ximénez C, Morán P, Rojas L, Valadez A, Gómez A. Reassessment of the epidemiology of amebiasis: state of the art. Infect Genet Evol. 2009 Dec. 9(6):1023-32. [Medline].
Stauffer W, Abd-Alla M, Ravdin JI. Prevalence and incidence of Entamoeba histolytica infection in South Africa and Egypt. Arch Med Res. 2006 Feb. 37(2):266-9. [Medline].
Stanley SL Jr. Amoebiasis. Lancet. 2003 Mar 22. 361 (9362):1025-34. [Medline].
Tengku SA, Norhayati M. Public health and clinical importance of amoebiasis in Malaysia: a review. Trop Biomed. 2011 Aug. 28(2):194-222. [Medline].
Caballero-Salcedo A, Viveros-Rogel M, Salvatierra B, Tapia-Conyer R, Sepulveda-Amor J, Gutierrez G, et al. Seroepidemiology of amebiasis in Mexico. Am J Trop Med Hyg. 1994 Apr. 50(4):412-9. [Medline].
Blessmann J, Van Linh P, Nu PA, Thi HD, Muller-Myhsok B, Buss H, et al. Epidemiology of amebiasis in a region of high incidence of amebic liver abscess in central Vietnam. Am J Trop Med Hyg. 2002 May. 66(5):578-83. [Medline].
Bowley DM, Loveland J, Omar T, Pitcher GJ. Human immunodeficiency virus infection and amebiasis. Pediatr Infect Dis J. 2006 Dec. 25(12):1192-3. [Medline].
Brindicci G, Picciarelli C, Fumarola L, Carbonara S, Stano F, Ciracì E, et al. Amoebic hepatic abscesses in an HIV-positive patient. AIDS Patient Care STDS. 2006 Sep. 20(9):606-11. [Medline].
Chen Y, Zhang Y, Yang B, Qi T, Lu H, Cheng X, et al. Seroprevalence of Entamoeba histolytica infection in HIV-infected patients in China. Am J Trop Med Hyg. 2007 Nov. 77(5):825-8. [Medline]. [Full Text].
Hsu MS, Hsieh SM, Chen MY, Hung CC, Chang SC. Association between amebic liver abscess and human immunodeficiency virus infection in Taiwanese subjects. BMC Infect Dis. 2008 Apr 16. 8:48. [Medline]. [Full Text].
Karp CL, Auwaerter PG. Coinfection with HIV and tropical infectious diseases. I. Protozoal pathogens. Clin Infect Dis. 2007 Nov 1. 45(9):1208-13. [Medline].
Park WB, Choe PG, Jo JH, Kim SH, Bang JH, Kim HB, et al. Amebic liver abscess in HIV-infected patients, Republic of Korea. Emerg Infect Dis. 2007 Mar. 13(3):516-7. [Medline]. [Full Text].
Infection by human immunodeficiency virus-1 is not a risk factor for amebiasis. Am J Trop Med Hyg. 2006 Nov. 75(5):1023. [Medline].
Hung CC, Ji DD, Sun HY, Lee YT, Hsu SY, Chang SY, et al. Increased risk for Entamoeba histolytica infection and invasive amebiasis in HIV seropositive men who have sex with men in Taiwan. PLoS Negl Trop Dis. 2008 Feb 27. 2(2):e175. [Medline]. [Full Text].
Muzaffar J, Madan K, Sharma MP, Kar P. Randomized, single-blind, placebo-controlled multicenter trial to compare the efficacy and safety of metronidazole and satranidazole in patients with amebic liver abscess. Dig Dis Sci. 2006 Dec. 51(12):2270-3. [Medline].
Hung CC, Wu PY, Chang SY, Ji DD, Sun HY, Liu WC, et al. Amebiasis among persons who sought voluntary counseling and testing for human immunodeficiency virus infection: a case-control study. Am J Trop Med Hyg. 2011 Jan. 84(1):65-9. [Medline]. [Full Text].
Acuna-Soto R, Maguire JH, Wirth DF. Gender distribution in asymptomatic and invasive amebiasis. Am J Gastroenterol. 2000 May. 95(5):1277-83. [Medline].
Nagata N, Shimbo T, Akiyama J, Nakashima R, Nishimura S, Yada T. Risk factors for intestinal invasive amebiasis in Japan, 2003-2009. Emerg Infect Dis. 2012 May. 18(5):717-24. [Medline].
Aristizábal H, Acevedo J, Botero M. Fulminant amebic colitis. World J Surg. 1991 Mar-Apr. 15(2):216-21. [Medline].
Andrade JE, Mederos R, Rivero H, Sendzischew MA, Soaita M, Robinson MJ, et al. Amebiasis presenting as acute appendicitis. South Med J. 2007 Nov. 100(11):1140-2. [Medline].
Rao S, Solaymani-Mohammadi S, Petri WA Jr, Parker SK. Hepatic amebiasis: a reminder of the complications. Curr Opin Pediatr. 2009 Feb. 21(1):145-9. [Medline]. [Full Text].
Goswami A, Dadhich S, Bhargava N. Colonic involvement in amebic liver abscess: does site matter?. Ann Gastroenterol. 2014. 27(2):156-161. [Medline]. [Full Text].
Hardin RE, Ferzli GS, Zenilman ME, Gadangi PK, Bowne WB. Invasive amebiasis and ameboma formation presenting as a rectal mass: An uncommon case of malignant masquerade at a western medical center. World J Gastroenterol. 2007 Nov 14. 13(42):5659-61. [Medline].
Loulergue P, Mir O. Pleural empyema secondary to amebic liver abscess. Int J Infect Dis. 2009 May. 13(3):e135-6. [Medline].
Dhawan VK, Malik SK. Acute pneumonia in the right lower lobe. Chest. 1975 Mar. 67(3):346-7. [Medline]. [Full Text].
Otan E, Akbulut S, Kayaalp C. Amebic acute appendicitis: systematic review of 174 cases. World J Surg. 2013 Sep. 37(9):2061-73. [Medline].
Sodhi KS, Ojili V, Sakhuja V, Khandelwal N. Hepatic and inferior vena caval thrombosis: vascular complication of amebic liver abscess. J Emerg Med. 2008 Feb. 34(2):155-7. [Medline].
Abd-Alla MD, Jackson TF, Gathiram V, el-Hawey AM, Ravdin JI. Differentiation of pathogenic Entamoeba histolytica infections from nonpathogenic infections by detection of galactose-inhibitable adherence protein antigen in sera and feces. J Clin Microbiol. 1993 Nov. 31(11):2845-50. [Medline]. [Full Text].
Haque R, Mollah NU, Ali IK, Alam K, Eubanks A, Lyerly D, et al. Diagnosis of amebic liver abscess and intestinal infection with the TechLab Entamoeba histolytica II antigen detection and antibody tests. J Clin Microbiol. 2000 Sep. 38(9):3235-9. [Medline]. [Full Text].
Helmy MM, Rashed LA, Abdel-Fattah HS. Detection and differentiation of Entamoeba histolytica and Entamoeba dispar isolates in clinical samples by PCR. J Egypt Soc Parasitol. 2007 Apr. 37(1):257-74. [Medline].
Singh A, Houpt E, Petri WA. Rapid Diagnosis of Intestinal Parasitic Protozoa, with a Focus on Entamoeba histolytica. Interdiscip Perspect Infect Dis. 2009. 2009:547090. [Medline]. [Full Text].
Tanyuksel M, Petri WA Jr. Laboratory diagnosis of amebiasis. Clin Microbiol Rev. 2003 Oct. 16(4):713-29. [Medline]. [Full Text].
Saidin S, Othman N, Noordin R. Update on laboratory diagnosis of amoebiasis. Eur J Clin Microbiol Infect Dis. 2019 Jan. 38 (1):15-38. [Medline].
Shamsuzzaman SM, Haque R, Hasin SK, Hashiguchi Y. Evaluation of indirect fluorescent antibody test and enzyme-linked immunosorbent assay for diagnosis of hepatic amebiasis in Bangladesh. J Parasitol. 2000 Jun. 86(3):611-5. [Medline].
Ahmad N, Khan M, Hoque MI, Haque R, Mondol D. Detection of Entamoeba histolytica DNA from liver abscess aspirate using polymerase chain reaction (PCR): a diagnostic tool for amoebic liver abscess. Bangladesh Med Res Counc Bull. 2007 Apr. 33(1):13-20. [Medline].
Fotedar R, Stark D, Beebe N, Marriott D, Ellis J, Harkness J. PCR detection of Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii in stool samples from Sydney, Australia. J Clin Microbiol. 2007 Mar. 45(3):1035-7. [Medline]. [Full Text].
Khairnar K, Parija SC. A novel nested multiplex polymerase chain reaction (PCR) assay for differential detection of Entamoeba histolytica, E. moshkovskii and E. dispar DNA in stool samples. BMC Microbiol. 2007 May 24. 7:47. [Medline]. [Full Text].
Stark D, van Hal S, Fotedar R, Butcher A, Marriott D, Ellis J, et al. Comparison of stool antigen detection kits to PCR for diagnosis of amebiasis. J Clin Microbiol. 2008 May. 46(5):1678-81. [Medline]. [Full Text].
Singh P, Mirdha BR, Ahuja V, Singh S. Loop-mediated isothermal amplification (LAMP) assay for rapid detection of Entamoeba histolytica in amoebic liver abscess. World J Microbiol Biotechnol. 2013 Jan. 29(1):27-32. [Medline].
Misra SP, Misra V, Dwivedi M. Ileocecal masses in patients with amebic liver abscess: etiology and management. World J Gastroenterol. 2006 Mar 28. 12(12):1933-6. [Medline].
Nagata N, Shimbo T, Akiyama J, Nakashima R, Niikura R, Nishimura S, et al. Predictive value of endoscopic findings in the diagnosis of active intestinal amebiasis. Endoscopy. 2012 Apr. 44(4):425-8. [Medline].
Gonzales ML, Dans LF, Martinez EG. Antiamoebic drugs for treating amoebic colitis. Cochrane Database Syst Rev. 2009 Apr 15. CD006085. [Medline].
Petri WA Jr, Singh U. Diagnosis and management of amebiasis. Clin Infect Dis. 1999 Nov. 29(5):1117-25. [Medline].
Salles JM, Salles MJ, Moraes LA, Silva MC. Invasive amebiasis: an update on diagnosis and management. Expert Rev Anti Infect Ther. 2007 Oct. 5(5):893-901. [Medline].
Kimura M, Nakamura T, Nawa Y. Experience with intravenous metronidazole to treat moderate-to-severe amebiasis in Japan. Am J Trop Med Hyg. 2007 Aug. 77(2):381-5. [Medline].
Moon TD, Oberhelman RA. Antiparasitic therapy in children. Pediatr Clin North Am. 2005 Jun. 52(3):917-48, viii. [Medline].
Gonzales MLM, Dans LF, Sio-Aguilar J. Antiamoebic drugs for treating amoebic colitis. Cochrane Database Syst Rev. 2019 Jan 9. 1:CD006085. [Medline].
Bammigatti C, Ramasubramanian NS, Kadhiravan T, Das AK. Percutaneous needle aspiration in uncomplicated amebic liver abscess: a randomized trial. Trop Doct. 2013 Jan. 43(1):19-22. [Medline].
Cordel H, Prendki V, Madec Y, Houze S, Paris L, Bourée P, et al. Imported amoebic liver abscess in France. PLoS Negl Trop Dis. 2013. 7 (8):e2333. [Medline].
McGregor A, Brown M, Thway K, Wright SG. Fulminant amoebic colitis following loperamide use. J Travel Med. 2007 Jan-Feb. 14 (1):61-2. [Medline].
Athié-Gutiérrez C, Rodea-Rosas H, Guízar-Bermúdez C, Alcántara A, Montalvo-Javé EE. Evolution of surgical treatment of amebiasis-associated colon perforation. J Gastrointest Surg. 2010 Jan. 14(1):82-7. [Medline].
Jha AK, Das G, Maitra S, Sengupta TK, Sen S. Management of large amoebic liver abscess--a comparative study of needle aspiration and catheter drainage. J Indian Med Assoc. 2012 Jan. 110(1):13-5. [Medline].
Shirley DA, Moonah S. Fulminant Amebic Colitis after Corticosteroid Therapy: A Systematic Review. PLoS Negl Trop Dis. 2016 Jul. 10 (7):e0004879. [Medline].
Chaudhry OA, Petri WA Jr. Vaccine prospects for amebiasis. Expert Rev Vaccines. 2005 Oct. 4(5):657-68. [Medline].
Snow MJ, Stanley SL Jr. Recent progress in vaccines for amebiasis. Arch Med Res. 2006 Feb. 37(2):280-7. [Medline].
Stanley SL Jr. Vaccines for amoebiasis: barriers and opportunities. Parasitology. 2006. 133 Suppl:S81-6. [Medline].
Quach J, St-Pierre J, Chadee K. The future for vaccine development against Entamoeba histolytica. Hum Vaccin Immunother. 2014 Feb 6. 10(6):[Medline].
Kikuchi T, Koga M, Shimizu S, Miura T, Maruyama H, Kimura M. Efficacy and safety of paromomycin for treating amebiasis in Japan. Parasitol Int. 2013 Dec. 62(6):497-501. [Medline].

Media Gallery

Trichrome stain of Entamoeba histolytica trophozoites in amebiasis. Two diagnostic characteristics are observed. Two trophozoites have ingested erythrocytes, and all 3 have nuclei with small, centrally located karyosomes.
Trichrome stain of Entamoeba histolytica cyst in amebiasis. Each cyst has 4 nuclei with characteristically centrally located karyosomes. Cysts measure 12-15 mm.
Entamoeba histolytica trophozoite. Image courtesy of Centers for Disease Control and Prevention.
Entamoeba histolytica cyst. Image courtesy of Centers for Disease Control and Prevention.
Life cycle of Entamoeba histolytica.
Gross pathology of intestinal ulcers due to amebiasis. Image courtesy of Centers for Disease Control and Prevention.
Histopathology of typical flask-shaped ulcer of intestinal amebiasis. Image courtesy of Centers for Disease Control and Prevention.
Entamoeba histolytica in liver aspirate, trichrome stain. Image courtesy of Centers for Disease Control and Prevention.
Histopathology of amebiasis. Image courtesy of Centers for Disease Control and Prevention.

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Author

Vinod K Dhawan, MD, FACP, FRCPC, FIDSA Professor, Department of Clinical Medicine, University of California, Los Angeles, David Geffen School of Medicine; Chief, Division of Infectious Diseases, Rancho Los Amigos National Rehabilitation Center

Vinod K Dhawan, MD, FACP, FRCPC, FIDSA is a member of the following medical societies: American College of Physicians, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, Royal College of Physicians and Surgeons of Canada

Disclosure: Nothing to disclose.

Coauthor(s)

Kerry O Cleveland, MD Professor of Medicine, University of Tennessee College of Medicine; Consulting Staff, Department of Internal Medicine, Division of Infectious Diseases, Methodist Healthcare of Memphis

Kerry O Cleveland, MD is a member of the following medical societies: American College of Physicians, Society for Healthcare Epidemiology of America, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

J Robert Cantey, MD Professor, Department of Medicine, Division of Infectious Diseases, Medical University of South Carolina

J Robert Cantey, MD is a member of the following medical societies: Alpha Omega Alpha, American Society for Microbiology, International Society of Travel Medicine, Southern Society for Clinical Investigation, Musculoskeletal Infection Society, American Society for Clinical Investigation, Infectious Diseases Society of America, Phi Beta Kappa

Disclosure: Nothing to disclose.

Chief Editor

Michael Stuart Bronze, MD David Ross Boyd Professor and Chairman, Department of Medicine, Stewart G Wolf Endowed Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center; Master of the American College of Physicians; Fellow, Infectious Diseases Society of America; Fellow of the Royal College of Physicians, London

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Medical Association, Association of Professors of Medicine, Infectious Diseases Society of America, Oklahoma State Medical Association, Southern Society for Clinical Investigation

Disclosure: Nothing to disclose.

Acknowledgements

Michael Stuart Bronze, MD Professor, Stewart G Wolf Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Medical Association, Association of Professors of Medicine, Infectious Diseases Society of America, Oklahoma State Medical Association, and Southern Society for Clinical Investigation