This increasingly common protozoal infection occurs in dogs, cats and people worldwide. Pets contract giardia by drinking contaminated water. In most circumstances there are no clinical signs but some pets develop persistent, bulky, smelly "cow manure" stools. These unpleasant bowel movements may occur intermittently or become chronic. Eggs are only shed by giardia intermittently but may be seen on microscopic examination of stool samples. Because negative smears frequently occur in infected individuals, blood tests (serology) are more accurate. Giardia is relatively simple to treat with either fenbendazole (Panacur) or metronidazole (Flagyl). Metronidazole should not be used in pregnant bitches.