Document Type : Original Article


1 Department of Medical Parasitology, Faculty of Medicine, P.O. Box 11562, Cairo University, Egypt.

2 Bio-Medical Research Centre, Norwich Medical School, University of East Anglia, Norwich, Norfolk, United Kingdom.

3 Department of Microbiology- Medical Parasitology Section, College of Medicine, University of Dammam, Dammam, Saudi Arabia.

4 College of Medicine, University of Dammam, Dammam, Saudi Arabia and Institute de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain.


Giardia intestinalis is frequent enteric protozoa, affecting humans worldwide. Human infections are mainly caused by two genetically different assemblages call A & B. This cross-sectional study characterized the Giardia genotypes isolated from the stool of symptomatic and asymptomatic Egyptians in Cairo and correlated these genotypes with the demographic and clinical data of the cases. Stool samples were collected from 389 individuals (245 complaining of gastrointestinal (GIT) symptoms and 144 apparently healthy asymptomatic individuals), and microscopically examined. Positive Samples for G. intestinalis were molecularly characterized by Copro-nPCR targeting beta-giardin gene, and then analyzed by RFLP for assemblage identification. Giardia was detected in 62 samples (15.9%); 53 samples in symptomatic cases (21.6%) and 9 samples in asymptomatic individuals (6.25%). DNA of positive samples was amplified by nPCR-RFLP assays. There was a significant predominance of assemblage B among symptomatic (82.7%) and asymptomatic (77.8%) groups, while the rest of samples had assemblage A. Among the clinical data, only flatulence was significantly associated with Giardia infection with assemblage B. Assemblage B is the predominant genotype found in Egypt in symptomatic and asymptomatic patients suggesting an anthropologic transmission cycle.