Prevalence and genotypic analysis of entamoeba histolytica isolates from Soroti by RFLP of serine-rich entamoeba histolytica protein gene locus

Abstract

Amoebiasis is an infection caused by water borne protozoan parasite Entamoeba histolytica. In Uganda where sanitation infrastructure and health education is not adequate, amoebiasis is still an important health problem. However there is little or no data on prevalence of this very important protozoan infection. In addition, microscopy remains the main method for the diagnosis of amoebiasis but cannot differentiate between Entamoeba dispar and Entamoeba histolytica infections. This has made determination of the prevalence of Entamoeba histolytica infections difficult. Hence there is need to perform molecular characterization of E. histolytica and E. dispar species. This study used both microscopy and polymerase chain reaction (PCR) to study prevalence and genotypic diversity of Entamoeba histolytica among humans in Soroti district, Eastern Uganda. Direct examination of wet stool, direct PCR and RFLP of the SREHP gene was performed. The overall prevalence of amoebiasis was 19.93%. Infection with Entamoeba histolytica/dispar was higher among males (22.14%) compared to females (17.39%). The 6-12 years age group recorded the highest prevalence at 24.44% but it was lowest in the 13-19 years age group at 17.65% (P<0.05). It was shown that only 36.7% (n=22) of the samples initially diagnosed as positive by microscopy were positive by PCR. The degree of agreement between microscopy and PCR was moderate (k=0.48). The prevalence of E. histolytica and E.dispar was found to be 7.31% and 12.6% respectively. Entamoeba histolytica isolates in the study area had eight different RFLP patterns. In conclusion, amoebiasis is an important public health problem in the study area and Entamoeba histolytica isolates are diverse in terms of strains.