RT Journal Article T1 Efficacy, safety and tolerance of imidocarb dipropionate versus atovaquone or buparvaquone plus azithromycin used to treat sick dogs naturally infected with the Babesia microti-like piroplasm A1 Checa Herráiz, Rocío A1 Montoya Matute, Ana A1 Ortega, Nieves A1 González Fraga, José Luis A1 Bartolomé, Adrián A1 Gálvez Esteban, Rosa María A1 Miró Corrales, Guadalupe A1 Marino, Valentina AB Background: Piroplasmosis caused by the Babesia microti-like piroplasm (Bml) is increasingly being detected in dogs in Europe. Sick dogs show acute disease with severe anaemia associated with thrombocytopenia with a poor response to current available drugs. This study assesses the safety and tolerance of three treatments and compares their efficacy over a full year of follow up in dogs naturally infected with Bml.Methods: Fifty-nine dogs naturally infected with Bml were randomly assigned to a treatment group: imidocarb dipropionate (5 mg/kg SC, 2 doses 14 d apart) (IMI); atovaquone (13.3 mg/kg PO q 8 h, 10 d)/azithromycin (10 mg/kg PO q 24 h, 10 d) (ATO); or buparvaquone (5 mg/kg IM, 2 d apart)/azithromycin (same dosage) (BUP). Before and after treatment (days 15, 45, 90 and 360), all dogs underwent a physical exam, blood tests and parasite detection (blood cytology and PCR). Clinical efficacy was assessed by grading 24 clinical and 8 clinicopathological signs from low to high severity.Results: Before treatment, most dogs had severe regenerative anaemia (88.13%) and thrombocytopenia (71.4%). Ontreatment Day 45, clinical signs were mostly reduced in all dogs, and by Day 90, practically all dogs under the ATO or BUP regimen were clinically healthy (76.4 and 88%, respectively). Highest percentage reductions in laboratory abnormalities (82.04%) were detected in animals treated with ATO. Over the year, clinical relapse of Bml was observed in 8 dogs (8/17) treated with IMI. However, on Day 360, these animals had recovered clinically, though clinicopathological abnormalities were still present in some of them. Parasitaemia was PCR-confirmed on Days 90 and 360 in 47.05 and 50% of dogs treated with ATO, 68 and 60.08% with BUP, and 94.1 and 73.3% with IMI, respectively. Even after 360 days, 13.3% of the dogs treated with IMI returned a positive blood cytology result. Conclusions: IMI showed the worse clinical and parasitological, efficacy such that its use to treat Bml infection in dogs is not recommended. The treatments ATO and BUP showed better efficacy, though they were still incapable to completely eliminate PCR-proven infection at the recommended dose. All three treatments showed good tolerance and safety with scarce adverse events observed. PB BioMed Central SN 1756-3305 YR 2017 FD 2017-03-13 LK https://hdl.handle.net/20.500.14352/112826 UL https://hdl.handle.net/20.500.14352/112826 LA eng NO Checa, R., Montoya, A., Ortega, N., González-Fraga, J. L., Bartolomé, A., Gálvez, R., Marino, V., & Miró, G. (2017). Efficacy, safety and tolerance of imidocarb dipropionate versus atovaquone or buparvaquone plus azithromycin used to treat sick dogs naturally infected with the Babesia microti-like piroplasm. Parasites & vectors, 10(1), 145. https://doi.org/10.1186/s13071-017-2049-0 NO Authors’ contributions: RC processed the blood samples and carried out the molecular and microscopy procedures, performed the statistical analysis of data, and drafted and finalized the manuscript. AM participated in the diagnostic assays, helped with the statistical analysis of data and reviewed the final manuscript. NO participated in the field study and the veterinarian enrolment procedures. JL and AB helped with the clinical cases enrolment and blood sample collection. RG and VM helped with the laboratory work, data collection and manuscript draft. GM conceived and coordinated the study, participated in its design and the field study, and drafted and reviewed the final manuscript. All authors read and approved the final manuscript. NO Ministerio de Economía, Comercio y Empresa (España) DS Docta Complutense RD 12 abr 2025