Very little is known of the occurrence and production and clinical significance of Giardia in pigs.  A small survey in Canada demonstrated a prevalece of 9% in animals from British Columbia, Alberta, Saskatchewan, Ontario and Quebec, but clinical disease in this host associated with Giardia is thought to be rare.  A recent study in Denmark suggests that parasite prevalence and intensity (as measured by cyst production) is higher in weaners (pigs 1 to 4 months of age) than in piglets or adults.