Ph. D  thesis was discussed at the faculty of Science, at the University of Basrah (A study of DNA polymorphism and virulence factors isolated from Entamoeba species in Basrah governorate), and showed the researcher's thesis ( Duaa Mardan Khalid). The study aimed to identify virulent strains of Entamoeba spp. responsible for amebic dysentery, one of the major global health problems, with a focus on their prevalence in Iraq and the routes of infection. It also examined factors influencing disease severity and the role of Entamoeba species in aggravating clinical symptoms. The study concluded that E. moshkovskii was more prevalent than E. histolytica, with a high level of genetic diversity among the strains. Expression analyses of virulence factors (CP, AP, GAL) indicated that disease severity primarily depends on the parasite’s genetic determinants. The study recommended adopting an integrated diagnostic approach combining microscopy, culture, and molecular techniques.