Clinicopathological abnormalities and outcome of acute Babesia canis infections in 23 dogs treated with imidocarb dipropionate.

Babesia canis infections are considered an emerging tick-borne disease most often with unspecific clinical signs. Two injections of 6.6 mg/kg bodyweight (BW) imidocarb dipropionate (ID) in a timeframe of 14 days are recommended for treatment. Babesia antibody levels are protective against severe disease. This prospective study aimed to describe clinicopathological abnormalities and Babesia antibody levels in 23 dogs with acute B. canis infections, defined by positive PCR sequencing results revealing B. canis on EDTA-blood, and to follow these dogs from T0 (diagnosis, first ID) to T1 (laboratory control, second ID), and T2 (laboratory control). Complete blood counts, biochemistry, coagulation profiles, Coombs' testing, and Babesia spp. antibody levels were determined. Thrombocytopenia, anemia, hyperbilirubinemia, and acute phase-responses were the most detected. ID dosage ranged from 1.7 to 7.0 mg/kg BW (median: 4.2 mg/kg BW). All PCR-results were negative at T1 and T2. At T1 (median 15 days after T0), laboratory abnormalities significantly improved but no further improvement was noted comparing T1 to T2 (median 32 days after T0). Initially serologically negative dogs built up Babesia antibody levels by T1, which mostly dropped by T2. All 23 dogs were PCR-negative at T1 besides the wide range in ID dosage. Laboratory abnormalities resolved quickly and all dogs had an uncomplicated course of disease. Dogs should be checked by PCR 14 days after the first imidocarb dipropionate injection. If the PCR result is negative and clinicopathological abnormalities have significantly improved, a second injection is not recommended to avoid a decrease in protective antibody levels.