RESUMO
Toxocara canis is one of the most important zoonotic parasites of dogs. The aim of the present study was to compare the efficacy of spinosad/milbemycin oxime and ivermectin/praziquantel in dogs naturally infected with Toxocara spp. We studied 200 dogs with a positive diagnosis of Toxocara spp. Through coproparasitoscopic analysis, two study groups of 100 dogs each were assigned: spinosad/milbemycin oxime at a dose of 30-60mg/kg and 0.75-1.0mg/kg, respectively, or ivermectin/praziquantel administered at a dose of 0.2mg/kg and 5mg/kg, respectively. Both groups received a single dose. Three stool samples, one at day 0 before treatment, and at 14 and 28days post-treatment were examined using concentration-flotation techniques. In both treatments, the number of Toxocara spp. eggs decreased; with spinosad/milbemycin oxime treatment, eggs decreased by 87% at 14days (P=0.008) and 94% at 28days after treatment, compared with 71% at day 14 and 88% at day 28 in dogs medicated with ivermectin/praziquantel. The spinosad/milbemycin oxime treated group showed a greater decrease in the number of Toxocara spp. positive dogs compared to the group receiving ivermectin/praziquantel.