Protothecosis in a dog.

A case of a disseminated algal infection is reported in a young rough-coated collie dog with progressive neurologic deficits, blindness, and hemorrhagic diarrhea. Prototheca zopfii organisms were cultured from feces, urine, and blood. At necropsy, granulomas containing typical organisms were identified within the proximal colon, heart, kidneys, and eyes.