Assessing the public health and zoonotic impacts of assemblages in domestic animals of southwestern Iran.

Domestic animals play a vital role in the spread and transmission of various zoonotic agents to humans. , an important enteric zoonotic parasite, is widespread globally. This research aimed to assess the presence and genetic diversity of assemblages in domestic animals in Shiraz, southern Iran. A total of 245 fresh fecal samples were collected from 87 dogs, 63 cats, and 95 cattle in Shiraz, the capital city of Fars province, between July 2021 and August 2022. None of the animals showed gastrointestinal signs such as diarrhea, and all fecal samples had normal consistency. Upon parasite observation using light microscopy, a DNA fragment of gene was amplified using nested-PCR. Using direct wet mount and Wheatley's trichrome staining examination, 9 out of 245 samples (3.7%; 1 from dogs and 8 from cattle) tested positive for . Molecular methods confirmed 1.1% (1/87) of dogs and 8.4% (8/95) of cattle to be positive. Giardiasis was not detected in cats. Phylogenetic analysis revealed that isolates infecting dogs and cattle in Shiraz belonged to three genotypes/assemblages: A, B (zoonotic), and E (non-zoonotic). In cattle, assemblage E (75%; 6/8), A (12.5%; 1/8), and B (12.5%; 1/8) were identified, while dogs were infected with assemblage A (100%; 1/1). In Shiraz, southwestern Iran, cattle and dogs could potentially transmit infections to humans.