Background: The genus Entamoeba has many species that are invasive or non-invasive (E. histolytica, E. dispar, and E. moshkovskii).The invasive E. histolytica is the main pathogenic amoeba in human. Amoebiasis involves several stages starting with the adherence of the parasite to the intestinal epithelium, followed by degradation, tissue invasion, and distribution to other organs. Results: The current study investigates the pathological changes of Entamoeba spp. infection in both rectum and cecum of experimental rats. The results showed the histological changes at the 7th, 14th, and 28th day post-infection for the three species. E. histolytica and E. moshkovskii infection showed less pathological changes compared to E. histolytica. These changes include the attachment of the trophozoites to the mucosal layer, significant surface epithelial changes such as dissociation and degeneration in the mucosal layer, and ulceration of the apical surface. Inflammatory cells infiltrate the varied regions, extending into the deep mucosa causing mild architectural alterations. These are features of amoebiasis. Conclusion: The pathological changes reported in E. dispar and E. moshkovskii were less severe than E. histolytica.

This study aims to determine the prevalence of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii by three methods of diagnosis (microscopic examination, cultivation and PCR) that were compared to obtain an accurate diagnosis of Entamoeba spp. during amoebiasis. Total (n=150) stool samples related to patients were (n = 100) and healthy controls (n= 50). Clinically diagnosed stool samples (n=100) were collected from patients attending the consultant clinics of different hospitals in Basrah during the period from January 2018 to January 2019. The results showed that 60% of collected samples were positive in a direct microscopic examination. All samples were cultivated on different media; the Brain heart infusion agar showed high efficiency and was the most suitable in cultivating the parasite. Data and results of molecular study were indicated by DNA extraction from stool samples and used in PCR technique with specific primers. This study identifies different infection percentage for the three species. The highest infection in Basrah patients was Entamoeba moshkovskii 15% followed by Entamoeba dispar 10% and Entamoeba histolytica, which was 5%.

Molecular and ultrastructure study of tight junction during experimental Molecular and ultrastructure study of tight junction during experimental Entamoeba spp. infection Entamoeba spp. infection