Case Report of a Fatal Babesia vulpes Infection in a Splenectomised Dog

Babesia vulpes is a small Babesia prevalent in foxes in Europe and mainly clinically affects dogs in north-western Spain. A dog imported from this region that had been living in Germany for three years developed splenic torsion. After splenectomy, the dog underwent immunosuppressive therapy because of autoimmune disease due to haemotrophic Mycoplasma sp. infection. As clinical signs worsened, small Babesia were detected in a blood smear and identified as B. vulpes by molecular analysis. Anaemia, thrombocytosis, elevated liver enzymes, and renal parameters were the most significant findings in blood analysis. The dog was treated with a combination of atovaquone (20 mg/kg BW, BID), proguanil hydrochloride (8 mg/kg BW, BID) and azithromycin (10 mg/kg BW, SID), which led to an increase in the cycle threshold in real-time PCR and the absence of B. vulpes in the blood smear. However, after clinical signs deteriorated, the dog was euthanised. This case report supports the recommendation to screen imported dogs for pathogens and highlights the impact of splenectomy on the course of infection.