Nasal colonization by Entamoeba gingivalis in a 13-year-old Italian Greyhound

A 13-year-old 4.6 kg castrated male Italian Greyhound was presented for evaluation of sneezing, bilateral epistaxis and mucoid nasal discharge of approximately 3 months duration. Severe periodontal disease was noted on physical exam. The patient's CBC was unremarkable. His biochemical profile revealed mild azotemia as well as mild electrolyte abnormalities. Rhinoscopy revealed a tan plaque present in the left dorsal meatus of the nasal cavity. Vigorous flushing yielded granular white particulates suspended in the saline, which were cytologically examined. Marked neutrophilic inflammation, a diverse bacterial population, and organisms consistent with amoebic trophozoites were identified. The remaining fluid was analyzed by PCR and sequencing, and Entamoeba gingivalis was identified. The dog's clinical signs improved dramatically after initiating treatment with clindamycin. Six weeks after diagnosis, a dental cleaning with multiple extractions was performed. Four weeks after the dental procedure, the dog was clinically normal. This report describes the clinical, hematologic, cytologic, and gross findings in a case of Entamoeba gingivalis infection in a dog.