Diagnosis of Giardia spp. in ruminants at Southern Brazil

Giardia spp. is a flagellated protozoan that parasitizes the small intestine of various mammals, birds, and amphibians, being transmitted via the fecal-oral route. Giardiasis is one of the most prevalent parasitic diseases in both developed and developing countries, with a prevalence of 0,1-5% and 20-30%, respectively, and is correlated with poor hygiene practices, such as irregular handwashing, which consequently contaminates food when handled. Cattle and sheep are sources of infection for humans due to the zoonotic potential of the species that affect them, especially calves, which play an important role in the dissemination of the parasite in the environment by excreting 10⁶ cysts per gram of feces, contaminating water sources, which, even when treated, only reduce and do not eliminate the protozoan. This study investigated the prevalence of Giardia spp. in ruminants in the southern region of Rio Grande do Sul, Brazil. Between June 2023 and April 2024, 384 fecal samples from young cattle and sheep were analyzed, collected directly from the rectal ampulla and subjected to coprological tests at the Laboratory, used the zinc sulfate centrifugal flotation technique to visualize protozoan cysts and calculate their prevalence. The results showed that 19,15% of sheep (27/141), 13,99% of cattle (34/243) and 15.88% in both species (61/384) tested positive for Giardia spp. This study revealed a significant prevalence of Giardia spp. in young ruminants in the southern region of Rio Grande do Sul, posing an important zoonotic risk.