TOXOCARA-CANIS INFECTION IN THE PARATENIC HOST - A STUDY ON THE CHEMOSUSCEPTIBILITY OF THE SOMATIC LARVAE IN MICE

A research on formulation and dosage strategies of anthelmintics have been conducted in mice experimentally infected with eggs of Toxocara c anis. Multidose treatments commenced at days 2, 14, 81, 87 and 123 pos tinfection. Results indicated no delectable difference in the chemosus ceptibility of the migrating early infection larvae and the resting hy pobiotic chronic infection larvae, Application of medicated dry food ( pellets) may be a simple way of improving efficacy of treatment compar ed to oral drenching. The larvicidal potential of fenbendazole (FBZ), albendazole (ABZ), flubendazole (FUBZ), oxibendazole (OBZ) and ivermec tin was assessed, Reductions of 84.2 to 99.7 or 88.8 to 100% of group mean larval counts were recorded after 20-30-day courses of feeding pe llets containing FBZ at 6 g kg(-1) or ABZ at 1.6 g kg(-1) food, respec tively. Efficacies of 57.8 to 88.2 or 81.1 to 32.0% were achieved by 2 0-day courses of feeding pellets medicated with FUBZ and OBZ at 1.6 g kg(-1) or 6.0 g kg(-1) food, respectively. Ivermectin at various dosin g regimens showed only moderate larvicidal potential. Efficacy rates w ere not closely correlated with the amount of drug taken by the animal s, The blood-brain barrier is permeable for the anthelmintics tested, and the brain of mice does not provide a site promoting survival of la rvae. (C) 1998 Elsevier Science B.V.