CHANGES IN HEMATOCRIT AFTER TREATMENT OF UNCOMPLICATED CANINE BABESIOSIS - A COMPARISON BETWEEN DIMINAZENE AND TRYPAN BLUE, AND AN EVALUATION OF THE INFLUENCE OF PARASITEMIA

It has been suggested that the antibabesial drug diminazene causes a r apid decline in haematocrit after treatment of dogs with high Babesia canis parasitaemias, compared with trypan blue. To test this, 19 dogs with clinically mild to moderate, uncomplicated babesiosis were placed in low, moderate or high parasitaemia groups, based on venous parasit aemias, and were allotted randomly to diminazene or trypan blue treatm ent groups. Haematocrit and parasitaemia were determined before treatm ent, and at 2, 6, 12, 18 and 24 hours. The drugs were compared for eff ects on haematocrit and parasite clearance. Changes in haematocrit aft er treatment were analysed. There were no significant differences betw een diminazene and trypan blue for haematocrit or parasite clearance. There was no correlation between initial parasitaemia and initial or p ost-treatment haematocrit. In all dogs, haematocrit fell following tre atment. The maximum mean reduction from the baseline (0 h) was 0.046 l /l (range 0.02-0.07 l/l); this most often occurred at 6 or 12 h. The 2 4 h haematocrit ranged from 70.5-113.6% of baseline (mean absolute hae matocrit 0.019 l/l below baseline). All dogs improved clinically durin g the study period. It was concluded that either diminazene or trypan blue can be safely used to treat dogs with clinically mild or moderate , uncomplicated babesiosis. Parasitaemia need not be taken into accoun t when deciding which antibabesial drug to administer and does not app ear to be related to the degree of anaemia.