A national survey on equine intestinal strongyle infections in Italy and Parasitological Assistance Program in Equids (PAPE)

INTRODUCTION. Horses are naturally parasitized by several genus/group of helminths and intestinal strongyles are the most common. Presently three anthelmintic classes are registered in horses: tetrahydropyrimidines, benzimidazoles and macrocyclic lactones (Gokbulut and McKellar, 2018 Vet Parasitol. 261: 27-52). The traditional approach to helminths control is based on interval dose program without a diagnosis, furthermore the frequent and reason less drug use has led to development of anthelmintic resistance (Leathwick et al., 2019 Vet Parasitol. 209: 210-20). Equine deworming scheme for adult horses is based on strongyle Fecal Egg Count (FEC) and on treatment of horses with FEC>200 egg per gram of feces (EPG) (Selective Treatment) (AAEP Internal Parasite Control Guidelines, 2019). FEC is also crucial to evaluate the treatment efficacy. The aims of this work were to carry out a survey on intestinal strongyles in horses in Italy and to propose a veterinary assistance considering a Parasitological Assistance Program in Equids (PAPE) based on coprological diagnosis (FEC). MATERIALS AND METHODS. The study was performed on 7,796 horses bred in 542 Italian farms. Individual FECs were performed using Mini-FLOTAC technique and a Sheather's sugar solution with a specific gravity of 1.250. Individual coprocultures were set up for each horse with FEC>200EPG. RESULTS AND CONCLUSIONS. Intestinal strongyle eggs were found in 420 (77.5%) tested farms with a prevalence at animal level of 57.6% (4,492/7,796). The average EPG was 441.2±622.0 (min 5 max 7,100). Regarding the egg shedding level, 71.4% of horses had a FEC <200 EPG (low contaminators), 11.3% between 200-500 EPG (moderate contaminators) and 17.3% >500 EPG (high contaminators). Coprocultures revealed L3 of Cyathostominae (100%), Poteriostomum (3.2%), Gyalocephalus (2.1%), Strongylus vulgaris (1.9%), Strongylus edentates (1.1%), Triodontophorus (0.7%) and Oesophagodontus (0.2%). Considering that FEC was <200 EPG in 71.4% (5,566) of horses, only 28.6% should be treated. Veterinarians must play an active role considering a Parasitological Program in Equids (PAPE) based on parasitological monitoring and Selective Treatment suggesting 4 individual FECs/year.