Canine blood smear
A labrador mixed breed dog was diagnosed with ehrlichiosis based on serology but did not respond to doxycycline treatment. Examination of blood smears revealed these organisms. What parasite is this?
This is Hepatozoon americanum, the agent of American canine hepatozoonosis. Dogs become infected when they ingest an infected tick containing sporulated oocysts or a transport host, such as a rabbit or rodent, harboring cystozoites. Dogs with hepatozoonosis require aggressive antiprotozoal therapy and do not respond to doxycycline treatment.
Have feedback on the cases or a special case you would like to share? Please email us. We will appropriately credit all submittors for any cases and photos provided.