Highlights & Basics
- Amebiasis is a common cause of diarrhea in infants in low-income countries and an emerging sexually transmitted infection in some developed countries. Amebiasis also causes colitis that can present with diarrhea and/or dysentery that can be acute or last more than 1 week. Abdominal tenderness and weight loss are common with amebic colitis.
- Amebic liver abscess presents with right upper quadrant pain. May not present with diarrhea, but will usually have a preceding history of diarrhea.
- Rare cause of brain abscess.
- Most patients will have traveled to or resided in an endemic area in the 12 months preceding presentation. Men who have sex with men and persons who engage in oral-anal sexual contact are at high risk for sexually transmitted amebiasis.
- Diagnosis is confirmed by detection of Entamoeba histolytica antigen or DNA in stool or antibodies against the parasite in serum.
Quick Reference
History & Exam
Key Factors
Other Factors
Diagnostics Tests
Treatment Options
Definition
Epidemiology
Etiology
Pathophysiology
Images
Cyst of Entamoeba histolytica: unstained (A), and iodine stained (B) after formalin-ether concentration of stool sample.
Amebic appendicitis with skin fistula two weeks after appendectomy (enhanced computed tomography).
Hematoxilin-Eosin stain (A-C) and Periodic acid-Schiff stain (D-F) of resected appendix of amebic appendicitis. Entamoebas are deeply dyed by Periodic acid-Schiff stain.
Cyst of Entamoeba histolytica: iodine stain of stool sample
Life-cycle of Entamoeba histolytica
Trophozoites of Entamoeba histolytica: trichrome stain of stool sample
Trophozoite of Entamoeba histolytica with pseudopod (red arrow): direct unstained stool sample.
Amebic ulcerations of the colon: colonic ulcers averaging 1 mm to 2 mm in diameter on gross pathology
Posterior-anterior and lateral CXR of a patient with amebic liver abscess: CXR findings include elevated right hemidiaphragm and evidence of atelectasis
Entamoeba histolytica brain abscess
Citations
Centers for Disease Control and Prevention. Yellow Book 2024: health information for international travel. Section 5: travel-associated infections & diseases - parasitic. Amebiasis. May 2023 [internet publication].[Full Text]
Public Health England. Interim public health operational guidelines for amoebiasis (Entamoeba histolytica). Oct 2017 [internet publication].[Full Text]
Gonzales MLM, Dans LF, Sio-Aguilar J. Antiamoebic drugs for treating amoebic colitis. Cochrane Database Syst Rev. 2019 Jan 9;1:CD006085.[Abstract]
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9. Centers for Disease Control and Prevention. Yellow Book 2024: health information for international travel. Section 5: travel-associated infections & diseases - parasitic. Amebiasis. May 2023 [internet publication].[Full Text]
10. Gunther J, Shafir S, Bristow B, et al. Short report: Amebiasis-related mortality among United States residents, 1990-2007. Am J Trop Med Hyg. 2011 Dec;85(6):1038-40.[Abstract]
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21. Roure S, Valerio L, Soldevila L, et al. Approach to amoebic colitis: Epidemiological, clinical and diagnostic considerations in a non-endemic context (Barcelona, 2007-2017). PLoS One. 2019;14(2):e0212791.[Abstract][Full Text]
22. Saidin S, Othman N, Noordin R. Update on laboratory diagnosis of amoebiasis. Eur J Clin Microbiol Infect Dis. 2019 Jan;38(1):15-38.[Abstract][Full Text]
23. Public Health England. Interim public health operational guidelines for amoebiasis (Entamoeba histolytica). Oct 2017 [internet publication].[Full Text]
24. Roy S, Kabir M, Mondal D, et al. Real-time PCR assay for the diagnosis of Entamoeba histolytica Infection. J Clin Microbiol. 2005;43:2168-72.[Abstract]
25. Haque R, Mollah NU, Ali IKM, 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;38:3235-39.[Full Text]
26. Yanagawa Y, Nagata N, Yagita K, et al. Clinical features and gut microbiome of asymptomatic entamoeba histolytica infection. Clin Infect Dis. 2021 Nov 2;73(9):e3163-71.[Abstract][Full Text]
27. Hosoe N, Kobayashi T, Kanai T, et al. In vivo visualization of trophozoites in patients with amoebic colitis by using a newly developed endocytoscope. Gastrointest Endosc. 2010;72:643-46.[Abstract]
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29. Okamoto M, Kawabe T, Ohata K, et al. Amebic colitis in asymptomatic subjects with positive fecal occult blood test results: clinical features different from symptomatic cases. Am J Trop Med Hyg. 2005 Nov;73(5):934-5.[Abstract]
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Key Articles
Referenced Articles
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