Genetic Characterization of Giardia lamblia in Infected Patients from Salah al-Din, Iraq, Using the TPI Gene

Abstract

This study evaluated Giardia lamblia infection in patients with diarrhea using the tpi gene and Nested PCR. One hundred stool samples were collected from patients attending Tikrit Teaching Hospital and health laboratories in Samarra and Ad-Dhuluiya between October 1, 2024, and July 1, 2025. Their ages ranged from  month to 41 years. Microscopic examination revealed that 36 samples 36% were positive for the parasite, with a higher infection rate in males 51.2% than in females 24.7%, and the highest infection rate was found in the month to 10 year age group 62.2%. DNA was extracted from the samples, and 83 samples were suitable for molecular analysis. The first nested-PCR reaction for the tpi gene recorded bands of 605 bp in 42 samples, while the second reaction showed bands of 530 bp in 38 samples. All positive samples in the second reaction were classified as genotype A 90.4%.