Genotypic and phylogenetic characterization of Giardia intestinalis from human and dairy cattle in Kafr El Sheikh Governorate, Egypt.

Giardiasis is a wide-spread intestinal disease of both humans and animals, with no morphological distinction between different assemblages and/or genotypes. The present study aimed to demonstrate the molecular identity of Giardia intestinalis parasites in clinical samples collected from infected cases screened at commercial laboratories and neonatal calves at dairy cattle farms, in Kafr El Sheikh. Molecular analysis based on PCR-sequence of triose phosphate isomerase (TPI) gene fragment. Results reported herein indicated that assemblage A was detected in 18/48 human isolates (37%) and 4/18 (22.2%) of the animal derived isolates, with subassemblage AII was the predominant in human samples and AI in the animal isolates. Whereas assemblage B was the predominant assemblage in the human infections (32/48: 66.7%), assemblage E was the major genotype in the animals samples (14/18: 77.8%). Genetic heterogeneity was pronounced feature in the generated sequences of all assemblages referring to wide diversity of Giardia population in Egypt. Also, results stressed the significance of neonatal calves as reservoir of zoonotic Giardia infections in human. Phylogenetic relationship of the analyzed isolates was inferred based on the reference sequences in the database.