Comparative therapeutic efficacy of Artesunate-Atovaquone-Azithromycin and Doxycycline-Clindamycin-Metronidazole regimens in dogs naturally infected with Babesia gibsoni.

Canine babesiosis, caused by Babesia gibsoni infection, is a potentially fatal tick-borne disease in dogs and depicts variable responses to combination therapies. This study was designed to evaluate a novel Artesunate-Atovaquone-Azithromycin (AAA) regimen against the standard Doxycycline-Clindamycin-Metronidazole (DCM) protocol in naturally infected dogs. The study included two treatment groups and a healthy control group, each comprising 10 dogs. Treatment efficacy was assessed through haemato-biochemical analysis and estimation of parasite load by relative quantification (RQ) real-time PCR over different observation points on day 0, 10, 28, 60, 90 and 180. The relative quantity of B. gibsoni 18S rRNA gene in canine blood samples was normalized against the canine β-actin gene using the 2-ΔΔCt method. The infected dogs exhibited normocytic-normochromic anaemia, thrombocytopenia, hypoproteinaemia, hyperglobulinemia, hyperbilirubinemia, azotaemia, high serum alkaline phosphatase and aspartate transaminase level whereas, mean creatinine level were found within normal physiological range. This study revealed that AAA therapy was associated with sustained superior efficacy with respect to haemato-biochemical remission and progressive reduction of parasitaemia, whereas DCM therapy revealed initial improvement followed by recrudescence. The negative Log RQ value demonstrated 10LogRQ times reduction in parasite associated transcript load on subsequent observation days compared to the baseline. A decrease exceeding 5 log RQ in parasite transcript level depicted a complete parasitic clearance, outperforming raw cycle threshold (Ct) values for clearance evaluation. These findings indicated that AAA regimen may be used as an efficient treatment alternative over conventional DCM therapy for the management of B. gibsoni infection in dogs.