Hepatozoon americanum: an emerging disease in the south-central/southeastern United States


  • The authors declare no conflicts of interest.

Address correspondence and reprint requests to
Thomas M. Potter, DVM, AUCVM – Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, 612 Hoerlein Hall, Auburn, AL 36849-5540, USA. Email: pottetm@auburn.edu
Submitted July 22, 2009; Accepted November 22, 2009.


Objective – To review the clinical epidemiologic and pathophysiologic aspects of Hepatozoon americanum infection in dogs.

Data Sources – Data from veterinary literature were reviewed through Medline and CAB as well as manual search of references listed in articles pertaining to American canine hepatozoonosis.

Veterinary Data Synthesis – H. americanum is an emerging disease in endemic areas of the United States. It is vital that practitioners in these areas become familiar with the clinical syndrome of hepatozoonosis and the diagnostic modalities that can be utilized to document the presence of infection. Additionally, veterinarians must understand the epidemiology of the disease in order to better prevent infections in their veterinary patients. Recent data have been published that shed new light on transmission of H. americanum to dogs; however, much remains unknown regarding patterns of infection and the natural vertebrate host source.

Conclusions – While the prognosis for untreated H. americanum remains poor, for patients in which the disease is recognized and properly treated the outcome is favorable. Understanding the complex life cycle, numerous clinical symptoms, and treatment protocol will assist veterinarians who are treating patients with hepatozoonosis.