Laboratory diagnosis of Giardia duodenalis infection in dogs.

Results of trichrome staining of fecal samples and intestinal contents preserved in polyvinyl alcohol fixative, fecal flotation utilizing unpreserved feces, and enzyme-linked immunosorbent assay of serum specimens were compared for the diagnosis of Giardia duodenalis infections in dogs. Trichrome staining of preserved fecal samples resulted in the identification of 44 (92%) of the 48 infected dogs from a group of 200 dogs. Trichrome staining of preserved intestinal contents resulted in the identification of 26 (54%) of the infected dogs, and fecal flotation resulted in the identification of 23 (48%) of the infected dogs. Giardia duodenalis antibodies were not detected consistently in the sera of infected dogs.