Epidemiological, clinical, and diagnostic data on intestinal infections with Entamoeba histolytica and Entamoeba dispar among returning travelers.

Background: Among travelers returning from the tropics, Entamoeba spp. are among the most frequently detected intestinal parasites, mainly the presumable apathogenic E. dispar and the pathogenic E. histolytica. Methods: Among 5,378 travelers seeking diagnosis and treatment for intestinal infections at the travel clinic of the University of Munich between 2005 and 2009, 103 laboratory-confirmed amebiasis cases were detected. The study compares the results of various diagnostic tests among these patients, analyzes data on co-infections and clinical symptoms, and determines the risk for acquiring amebiasis. Results: Initial screening tests (stool microscopy, coproantigen enzyme-linked immunosorbent assay [ELISA]) were positive in 82.5 and 93.9%, respectively. Fecal samples from patients with positive screening test results were subjected to polymerase chain reaction (PCR), which detected E. histolytica in 9.7% and E. dispar in 88.3% of the cases. The majority of E. histolytica cases and more than half of the E. dispar cases had intestinal symptoms typical for amebiasis. In 53.4% of the cases, intestinal co-infections were found, mostly Blastocystis hominis (39.8%), Giardia lamblia (10.7%), Campylobacter spp. (4.9%), and Salmonella typhi (2.9%). The risk for travelers to be infected with E. histolytica or E. dispar was highest for destinations in West Africa, East Africa, and South and South-East Asia. Conclusion: Stool microscopy and coproantigen ELISA are appropriate screening tests for intestinal Entamoeba infections among travelers, but intestinal co-infections are common. PCR is highly recommended as the diagnostic method of choice for the differentiation of Entamoeba spp. The presumable apathogenic E. dispar seems to provoke intestinal symptoms. [ABSTRACT FROM AUTHOR]