The prophylactic activity of imidocarb against tick-transmitted parasitic infections

Abstract

Imidocarb — 3,3’bis-(2-imidazolin-2-yl) carbanilide dipropionate (Carbesia®, Imizol®) is highly active against all species of the protozoan parasite Babesia, with the possible exception of B. gibsoni of dogs, and B. felis in cats. It is very active against Anaplasma marginale, a rickettsia-like parasite of ruminants. It is not effective against Theileria. Imidocarb exerts a prophylactic effect against some species of Babesia 3,5 which may last for several weeks. The duration of prophylaxis seems to depend on the severity and virulence of challenge4. Imidocarb has no prophylactic effect on Anaplasma. The mode of action of imidocarb is not certain, although two mechanisms have been suggested. The effect of imidocarb on Trypanosoma brucei has been antagonized with excess polyamines, which suggests that the drug interfered with the production or utilization of polyamines1. Imidocarb blocks the entry of inositol, an essential nutrient, into the erythrocyte containing the Babesia parasite, apparently resulting in the ‘starvation’ of the parasite (Elford, unpublished). This mechanism would readily explain the prophylactic effect of imidocarb since the presence of very small quantities of imidocarb on the surface of the erythrocyte could make it unattractive to the parasite.