Molecular characterisation of Babesia gibsoni infection from a Pit-bull terrier pup recently imported into South Africa

Canine babesiosis caused by Babesia gibsoni was diagnosed in a 3-month-old Pit-bull pup during a routine clinical examination. Diagnosis was confirmed by way of smear examination, PCR, Reverse Line Blot (RLB) and sequence analysis which showed 100% homology with B. gibsoni (Japan AB118032) and Babesia sp. (Oklahoma) (AF205636). Haematology showed moderate anaemia and severe thrombocytopenia. Treatment was initiated with diminazene aceturate (Berenil RTU) followed by 2 doses of imidocarb diproprionate (Forray-65) 3 days and 14 days later, respectively. Babesia gibsoni DNA was still detectable 2 weeks post-treatment on the PCR/RLB test. A 10-day course of combination drug therapy using atovaquone and azithromycin was initiated. Blood samples taken on Day 1 and Day 40 after completion of treatment were negative for B. gibsoni DNA on PCR/RLB test. The implications of a possible introduction of B. gibsoni into South Africa are discussed.