Abstract:
Under stressful conditions, black rhinoceroses that are sub-clinical carriers of Babesia bicornis can succumb to babesiosis. After 16
days in captivity, a five-year-old female black rhino captured for relocation presented with inappetence, abdominal discomfort and
constipation. After chemical immobilisation, dry faecal balls were removed from the rectum, peripheral blood smears were made
and blood collected into EDTA tubes. She was treated prophylactically for colic with flunixin meglumine, penicillin and doramectin.
Piroplasms were seen on fixed and stained peripheral blood smears. Overnight she developed severe haemoglobinuria, a sign
consistent with babesiosis. Subsequently, DNA extracted from a blood specimen reacted with the B. bicornis probe on Reverse Line
Blot (RLB) assay, confirming the diagnosis of babesiosis. Specific treatment consisted of 14 ml imidocarb dipropionate (dosage
2.4 mg/kg) administered intramuscularly by pole syringe. Fifteen days later the patient was still moderately anaemic, with the red
blood cell (RBC) count, haematocrit and haemoglobin concentration within normal ranges but on microscopic examination there
was a marked RBC macrocytosis and polychromasia indicative of a regenerative anaemia. DNA extracted from blood collected
at that time did not react with the B. bicornis probe on RLB assay, indicating that treatment with imidocarb had been effective.
Once the patient’s appetite improved, she started gaining weight. After 82 days in captivity and 65 days after babesiosis had been
diagnosed, she was released at the site where she had been captured.
