Hepatozoon canis in dogs: treatment and prevention
4-year-old Galgo from a shelter in Extremadura with fever, weight loss and muscle pain. The smear shows Hepatozoon canis gamonts in neutrophils. It arrived with many Rhipicephalus ticks and nibbled at them to remove them.
Which statement about management is correct?
chevron_right Show answer and explanation
A. Infection is transmitted by the tick bite, so an acaricide that kills the tick before it feeds is enough
H. canis is not transmitted by the bite: the dog is infected by ingesting a tick containing oocysts. Tick control helps, but the key point is preventing ingestion of ticks (while grooming or eating prey).
B. Atovaquone with azithromycin clears the infection in 10 days
That combination is used for small babesias. It is not the established treatment for H. canis.
C. Imidocarb dipropionate (often with doxycycline) reduces parasitaemia and signs, but does not clear the infection
Correct. Imidocarb every 14 days until gamonts disappear is the most widely used treatment. Infection persists in tissues and relapses may occur, so rechecks are needed. Look for coinfections (Leishmania, Ehrlichia), which are common in these dogs.
D. It is an incidental finding of no clinical importance that needs no treatment
With low parasitaemia it may be subclinical, but this dog has clinical signs. High parasitaemia causes fever, cachexia and anaemia, and can be severe.
lightbulb Key takeaway
H. canis is transmitted by ingesting infected Rhipicephalus sanguineus and also vertically. Prevent it with continuous tick control on the dog and in the environment, and by stopping it eating prey or offal. Suspect coinfections in shelter or hunting dogs.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.