Breed: Labrador Retriever
3 year old Lab that presented to his veterinarian (his owner’s brother) with hemorrhagic diarrhea for at least one week, lethargy, uveitis and acute onset of blindness and incoordination .
The patient had a mild inflammatory and superimposed stress leukogram with a mild nonregereative anemia. The chemistries were sent out but he collected urine via free catch and looked at it in house.Click here for the IDEXX Pathology Report on this case.
Urine sediment: The slide reveals low numbers of uniform but mildly degenerate squamous epithelial cells as well as large numbers of elongated oval shaped structures of variable size ranging from 5-15 microns. The structures revealed a negative staining cell wall. Some of the structures were basophilic and granular appearing while others were more uniformly darkly basophilic. Several of the structures contained multiple endospores.
Prototheca is a ubiquitous type of algae that does not usually infect dogs, but it can and is usually refractory to any treatment (grave prognosis). It is presumed to be acquired via ingestion from a pond or other source of water. It typically is associated with GI signs first but often disseminates to the eyes/retinas, CNS, and kidneys.
The presence of this organism in the urine is due of dissemination to the kidneys.
The organism reproduces via endosporulation as can be seen in the photos.
All though this condition can be diagnosed via cytology alone. This patient had a sample submitted for PCR and was identified as Prototheca zopfii.
Prototheca infection can occur in other species but, in contrast to the dog, seems to disseminate infrequently. This condition is usually associated with mastitis in cows and in immunocompetent people a cutaneous lesion may occur resulting from traumatic inoculation.