Investigation of ivermectin resistance towards equine gastrointestinal nematodes in endurance horses in terengganu

An abstract of the research paper presented to the Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, in partial requirement on the course DVT 55204 – Research Project. Horses, notably those in Malaysia, are exposed to a diverse array of gastrointestinal nematodes. The growing resistance of parasites to anthelmintic medications in horses is one of the most troubling issues for horse owners, veterinarians, and others in the industry today. There is minimal information on the contribution of horses to clinical illness, parasite epidemiology, and anthelmintic resistance. Hence this study aimed to determine the resistance of Ivermectin in a horse stable, as well as to conclude its efficacy. Horses that fit the inclusion criteria, horses with fecal egg count (FEC) >50 and have not been dewormed for the past 6 months were chosen and treated with Ivermectin orally in proper dosage. The enrolled horse was screened with a fecal egg count reduction test (FECRT) and divided into treatment and control groups with approximately similar means of fecal egg count (FEC). Fecal samples that were collected during pre- and post-treatments were subjected to the Modified McMaster test. Then, a fecal egg count reduction test (FECRT) was performed on 28 endurance horses, from October to December 2022 to determine the resistance of nematodes towards Ivermectin in horses. Ivermectin was found to be resistant in horses enrolled for the study with an 80% of FECRT. The results concluded that there is evidence of Ivermectin resistance in equine cyathostomes in horses enrolled for the study.
Keywords: Anthelminthic resistance, Horses, Ivermectin, FECRT, FECR%, Nematodes