Molecular identification of Entamoeba spp. in humans and cattle in Baghdad, Iraq.

Background and aim: A total of 10% of the global population succumbs to amoebiasis yearly, equating to 50,000-100,000 recorded fatalities. It is closely associated with contaminated food and water supplies due to human feces. The disease's pathophysiology remains a subject of ongoing debate among experts. Some experts attribute the role of the host's conditions, parasite species and strain, and infection intensity in eliciting clinical symptoms. The aim of this study was to perform molecular identification of Entamoeba species isolated from humans and cattle.

Materials and methods: Stool samples from three hundred patients and one hundred cattle were collected from different regions, age groups, and sexes in Baghdad for microscopic examination. One hundred randomly chosen patient and cattle stool samples underwent microscopic examination and conventional polymerase chain reaction (PCR) targeting the 18S rRNA gene. Phylogenetic tree analyses were performed for Entamoeba species identification.

Results: The infection rate in humans differed significantly (p < 0.05) between age groups and genders, totaling 38%. The infection rate in cattle, determined by conventional PCR, differed significantly (p < 0.05) between age groups and genders, amounting to 58%. Ten PCR products with positive results were sequenced and deposited in GenBank database. Sequence analysis detected that Eight sequences belong to E. histolytica (OM268853.1, OM268854.1, OM268855.1, OM268857.1, OM268858.1, OM268860.1, OM268861.1, and OM268862.1) and two sequences belong to E. dispar (OM268856.1 and OM268859.1) in humans, while 10 sequences (ON724165.1 to ON724174.1) belongs to E. histolytica in cattle.

Conclusion: The increased susceptibility of cattle to E. histolytica suggests a considerable role in human infection and substantial public health risks. Further research should be conducted on the many virulence factors such as HM1:IMSS strain, cysteinprotease (Cp1), Gal/lectin, etc. of E. histolytica and E. dispar.