A Review of the Global Burden, New Diagnostics, and Current Therapeutics for Amebiasis

Abstract

Amebiasis, due to the pathogenic parasite Entamoeba histolytica, is a leading cause of diarrhea globally. Largely an infection of impoverished communities in developing countries, amebiasis has emerged as an important infection among returning travelers, immigrants, and men who have sex with men residing in developed countries. Severe cases can be associated with high case fatality. Polymerase chain reaction-based diagnosis is increasingly available but remains underutilized. Nitroimidazoles are currently recommended for treatment, but new drug development to treat parasitic agents is a high priority. Amebiasis should be considered before corticosteroid therapy to decrease complications. There is no effective vaccine, so prevention focuses on sanitation and access to clean water. Further understanding of parasite biology and pathogenesis will advance future targeted therapeutic and preventative strategies.

Keywords: HIV; MSM; PCR; amebiasis; burden; colitis; diarrhea.

Figure 1.

Entamoeba histolytica in stool and pathological features of intestinal amebiasis. A, Cyst of E. histolytica/E. dispar stained with trichrome. Note the chromatoid body with blunt ends (red arrow). B, Trophozoite of E. histolytica with ingested erythrocytes stained with trichrome. The ingested erythrocytes appear as dark inclusions (red arrow). The parasite shows nuclei that have the typical small, centrally located karyosome and thin, uniform peripheral chromatin. C, Intestinal tissue from a patient with amebic colitis showing multiple ulcers. D, Classic flask-shaped ulcer of amebiasis (courtesy of the Centers for Disease Control and Prevention).

Figure 2.

Amebic colitis. Immunohistochemical staining of trophozoites (brown) using specific anti–Entamoeba histolytica macrophage migration inhibitory factor antibodies in a patient with amebic appendicitis.