Babesia canis babesiosis in dogs: treatment
4-year-old German Shepherd from Navarre that goes into the countryside. In November it has fever, lethargy, pale mucous membranes and dark urine. There is regenerative anaemia and thrombocytopenia, and the smear shows large pear-shaped piroplasms. PCR confirms Babesia canis. Perfusion is acceptable.
What is the most appropriate treatment?
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A. Doxycycline for 28 days
Doxycycline is the treatment for ehrlichiosis and anaplasmosis, but it is not effective as sole treatment for B. canis babesiosis.
B. Immunosuppressive prednisolone as the first measure, because of the haemolysis
Although haemolysis has an immune-mediated component, the priority is to clear the parasite. Immunosuppression without treating the cause is not indicated and may worsen the infection.
C. Atovaquone and azithromycin for 10 days
This is the treatment for small babesias such as B. gibsoni. For B. canis the drug of choice is imidocarb, which is simpler and cheaper.
D. Imidocarb dipropionate (two doses 14 days apart), with prior atropine to prevent cholinergic effects
Correct. Imidocarb is effective against large babesias. It causes cholinergic effects (salivation, diarrhoea, tremors, tachycardia), which are prevented with atropine. Add supportive care (fluids and transfusion if anaemia is severe).
lightbulb Key takeaway
B. canis is transmitted by Dermacentor reticulatus, active in autumn and spring in northern Spain; it causes more severe disease than B. vogeli (Rhipicephalus, Mediterranean climate). Watch for complications: acute kidney injury, pancreatitis, ARDS and cerebral babesiosis.
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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.