title: Comparative efficacy of moxidectin and ivermectin against hypobiotic and encysted cyathostomes and other equine parasites.
abstract: Efficacies of moxidectin and ivermectin were compared in four groups of eight ponies with natural parasite infections: placebo (Control), oral moxidectin gel at 0.3 mg kg-1 of body weight (Mox 0.3), oral moxidectin gel at 0.4 mg kg-1 of body weight (Mox 0.4), and oral ivermectin paste at 0.2 mg kg-1 of body weight (Ivermectin). Fecal samples were taken 0 and 2 weeks after treatment. Animals were necropsied and worms were collected 2 weeks after treatment. Moxidectin and ivermectin showed similar efficacy (99%) against adult cyathostomes, Strongylus spp., Triodontophorus spp. and Habronema muscae. Both drugs were also more than 98% effective against luminal cyathostome and Oxyuris equi fourth stage larvae (L4). Neither drug was effective (0-10.1%) against hypobiotic early third stage cyathostome larvae (EL3). Moxidectin was moderately effective (62.6-79.1%) in removing encysted cyathostome late third stage larvae (LL3) and L4, whereas ivermectin was ineffective (0%) against these stages. By contrast, ivermectin was 95.4% effective against Gasterophilus spp. third instar stage, whereas moxidectin was only 0-20.4% effective.
authors.affiliation: Department of Veterinary Preventive Medicine, Ohio State University College of Veterinary Medicine, Columbus 43210.
authors.forename: L
authors.initials: L
authors.lastname: Xiao
authors.forename: R P
authors.initials: RP
authors.lastname: Herd
authors.forename: G A
authors.initials: GA
authors.lastname: Majewski
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D005243:Feces / Q000469:parasitology; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy; D006736:Horses; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy / Q000662:veterinary*; D007559:Ivermectin / Q000627:therapeutic use*; D018942:Macrolides; D008297:Male; D010270:Parasite Egg Count / Q000662:veterinary; D013319:Strongyle Infections, Equine / Q000188:drug therapy*
chemical_list: D000871:Anthelmintics; D000900:Anti-Bacterial Agents; D018942:Macrolides; D007559:Ivermectin; C027837:moxidectin