Effect of ivermectin on Toxocara canis larvae in vitro and in vivo at different migratory stages.

INTRODUCTION

Ivermectin has shown potent activity against various nematodes.

OBJECTIVE

Evaluation of the efficacy of ivermectin against Toxocara canis larvae.

MATERIALS AND

METHODS

In vitro assessment was conducted using larval migration inhibition test and scanning electron microscopy (SEM). In vivo, ivermectin was administered orally to mice at a single 0.2 mg/kg dose at 2 (group I), 7 (group II), or 15 days (group III) post-infection. Efficacy was evaluated through brain larval counts and histopathological examination of liver and brain.

RESULTS

In vitro, ivermectin at concentrations of 10 μg/ml and 100 μg/ml inhibited larval migration by 8.5% and 87%, respectively. SEM showed cuticular damage after 24 and 48 hours with 100 μg/ml ivermectin. In vivo, brain larval counts significantly decreased in groups I and II (22.67 ± 5.41 and 37.17 ± 5.98), with no significant reduction in group III (130.5 ± 9.01). Histopathology of the liver at four weeks post-infection in groups I and II revealed numerous granulomas with degenerated larvae. The brain showed a marked reduction in larval presence and inflammation in groups I and II, while group III findings were similar to those of the control group.

CONCLUSION

Ivermectin is effective against T. canis larvae during early migratory stages but shows limited efficacy against late-stage larvae.