Companion Animals

Canine Hepatozoonosis: Welfare and Emerging Disease

Welfare guide to hepatozoonosis in dogs -- a tick-transmitted disease causing debilitating illness.

Key Facts

Canine hepatozoonosis is caused by Hepatozoon canis (old world) or H. americanum (new world) -- tick-transmitted protozoa
European form (H. canis) is typically mild but North American form causes severe debilitating disease
Dogs become infected by ingesting infected ticks -- not by tick bite in the typical sense
Clinical signs include fever, weight loss, lethargy, muscle pain, and reluctance to move
Diagnosis requires blood smear or PCR testing -- clinical signs alone are insufficient
Treatment is complex and prolonged -- North American form often requires lifelong management
Dogs with American hepatozoonosis experience profound muscle pain and disability
Prevention centres on tick control to prevent ingestion of infected ticks -- regular tick removal and preventives

Welfare Significance

Hepatozoonosis causes significant welfare deterioration through chronic systemic illness and in the American form, debilitating muscle pain. The welfare challenge is managing a disease that cannot be cured but can be controlled. Prevention through tick control is the most effective welfare intervention -- stopping the disease before it starts.

What You Can Do

Use licensed tick preventives year-round for dogs in tick-endemic areas
Check dogs regularly for ticks and remove promptly using correct technique
Seek veterinary assessment for dogs returning from southern Europe with unexplained fever and lethargy
Report any suspected hepatozoonosis to your vet -- it is an emerging disease in some UK regions