Abstract

The epidemiology of Entamoeba histolytica infection in Sudan is poorly understood. This is due to the inability to differentiate E. histolytica from the non pathogenic, Entamoebadispar. Old methods used such as direct microscopy and culturing are insensitive compared to polymerase chain reaction (PCR). In this study, light microscopy and PCR were utilized to study the prevalence of Entamoeba infection in patient attending University of Medical Science and Technology (UMST) hospital, in Khartoum, Sudan. By microscopy 196 stool samples were reported as positive for E. histolytica. PCR detected infections caused by E. histolytica in 54% (106 of 196), and Entamoeba dispar in 51% (100 of 196) of stool samples. By PCR also mixed infections were detected with both E. histolytica andE. dispar in 5% (10 of 196) of stool samples. All 50 negative stool samples examined by microscopy were negative by PCR. The inability to distinguish E. histolytica from the morphologically similar E. dispar in stool samples is the main limitation of microscopic methods used mainly all laboratories in Sudan. All the 196 samples tested were reported positive for E. histolytica by microscopy but in this study it is shown that only 54% (106 of 196) were positive for E. histolytica. The other 51% (100 of 196) were positive for E. dispar, which were misdiagnosed as E. histolytica infections and mistreated with anti-amoebic drugs. Thus, PCR is recommended for detection and accurate identification ofEntamoeba species in stool samples.

Key words: Entamoeba histolytica, Entamoeba dispar, polymerase chain reaction (PCR), Sudan.

Abbreviation

Abbreviations: PCR, Polymerase chain reaction; UMST, university of medical science and technology; PBS, phosphate buffer saline; RBCs, red blood cells.