Comparative Anthelmintic Efficacy of Ivermectin and Levamisole in Dogs Naturally Infected with Gastrointestinal Nematodes in Bishoftu, Central Ethiopia

Background: Gastrointestinal helminths are among the most common causes of diseases in dogs, livestock, and zoonotic infections. Despite the widespread distribution of parasitic diseases in dogs, they have received very little attention in Ethiopia. Moreover, the improper use of drugs has resulted in ineffective control of helminths and anthelmintic resistance. Thus, an experimental study was conducted to determine the comparative anthelmintic efficacy of Ivermectin and Levamisole in dogs naturally infected with gastrointestinal nematodes. Methods: The experiment was conducted on 180 dogs identified with at least 100 eggs per gram of feces and randomly assigned into three treatment groups. Treatment Group I was treated with Ivermectin, Treatment Group II was treated with Levamisole, and Treatment Group III was the control. Fecal samples were collected on day 0 and day 14. Fecal egg count reduction analysis was conducted to determine the efficacy of anthelmintic drugs. Results: Among 180 dogs, the mean fecal egg count was 1249.02 (95% CI: 1139.57–1358.47) at day 0. This study indicated a significant difference (p < 0.05) in the mean fecal egg count among the treatment groups at day 14. The mean fecal egg count was reduced to 37.9 (95% CI: 20.93–54.87) and 88 (95% CI: 57.54–118.46) in dogs treated with Ivermectin and Levamisole, respectively. The fecal egg count reduction analysis indicated significant reductions in fecal egg count in dogs treated with anthelmintics at day 14. The fecal egg count reduction was 97.15% (95% CI: 91.12–99) and 93.23% (95% CI: 84.29–98) in dogs treated with Ivermectin and Levamisole, respectively. Conclusions: This study demonstrates the satisfactory efficacy of Ivermectin, whereas Levamisole was suspected of resistance in the treatment of gastrointestinal nematodes in dogs at the recommended dosage. Thus, the present study suggests Ivermectin treatment, a combination of Levamisole, and further studies on anthelmintics for dogs against gastrointestinal helminths.