Comparative Larvicidal Potency of Ivermectin, Doramectin, Moxidectin, and Eprinomectin Against Dromedary Camel Nasal Bots (Cephalopina titillator)

This study evaluates the efficacy of four commonly used antiparasitic drugs, i.e. ivermectin, doramectin, moxidectin, and eprinomectin against C. titillator third stage larvae (L3) in dromedary camels. In order to determine and compare the half-maximal inhibitory concentration (IC50) values of ivermectin, doramectin, moxidectin, and eprinomectin for controlling nasal myiasis in dromedary camels, present study was conducted on L3 collected from 200 naturally infested camels from the Eastern Province of Saudi Arabia. Upon slaughter, L3 were collected from the nasopharynx of the infested camels and were incubated in DMEM supplemented with 50% foetal calf serum and penicillin/streptomycin (100 IU). This media was mixed with serially diluted concentrations of ivermectin, doramectin, eprinomectin, before moxidectin from 1 mg/ml to 125 ng/ml. The larvicidal effect of the four drugs was inferred by the IC50 values that were calculated using nonlinear fitting of dose-response inhibition equations. The IC50 values indicated that ivermectin was the most potent drug with an IC50 of 0.0735 ± 0.016 μg/ml, followed by doramectin (0.249 ± 0.116 μg/ml), eprinomectin (0.46 ± 0.24 μg/ml), and moxidectin (11.96 ± 2.21 μg/ml). The efficacy of ivermectin, doramectin and eprinomectin was significantly higher than that of moxidectin. Ivermectin and doramectin could be considered more potent drugs for treating camel nasal myiasis. The results have important implications for the development of effective treatment protocols for managing parasitic infestations in camel populations.