A comparison of the efficacy of isometamidium, amicarbalide and diminazene against Babesia canis in dogs and the effect on subsequent immunity.

Isometamidium, amicarbalide and diminazene were used to treat experimentally induced canine babesiosis. Relapse parasitaemias developed after treatment in all groups of animals. The relapse interval, however, was shorter and more relapses occurred after treatment with amicarbalide than either of the other 2 drugs. Only half of the dogs treated with either isometamidium or diminazene relapsed to infection. Challenge with homologous parasites 62 days after initial infection resulted in severe babesiosis in all 3 animals which had not developed relapse infections. Of the 9 animals which had relapses after treatment only 1 developed severe babesiosis following homologous challenge.