POST-TREATMENT RELAPSE RATES IN CANINE BABESIOSIS: A CLINICAL AND HEMATOLOGICAL STUDY

Abstract

The aim of the present study was to evaluate the post-treatment relapse incidences of canine babesiosis by means of an extensive clinical, hematological and molecular approach including 120 naturally infected dogs.  The dogs were all treated with standardised diminazene aceturate or imidocarb dipropionate and followed up by serial clinical examination, hematological profiling, biochemical analysis and quantitative PCR to determine parasite load over a 90 day period.  Baseline hematology indicated severe anemia (mean hemoglobin 7.2 g/dL) and thrombocytopenia but the patient improved after therapy.  Molecular diagnostics also revealed that some patients, even in the instance when they were better, still had low-level parasitemia.  acted on eighteen percent of dogs, with most relapsing within 30 to 60 days of treatment. Multivariate analysis showed that baseline parasitemia (>20,000 copies/mL), purebred, diminazene administration, and elevated CRP levels on day 14 were independent risk factors of relapse (p<0.05).  Biochemical abnormalities (elevated levels of ALT, AST, and bilirubin) were back to the normal range on day 90.  Immune profiling revealed that CRP and SAA were extremely higher in relapsing dogs. The Kaplan-Meier survival curve indicated that relapse-free survival was continually decreasing and the majority of relapses occurred within 60 days. These findings demonstrate the complexity of the processes of babesiosis relapse, the inability of the existing methods to eradicate the parasites in some cases, and the necessity of molecular diagnosis, individual approach to treatment, and extended observation to reduce the chances of relapse in the regions where the tick-borne disease is endemic.