Resistance to pyrantel embonate and efficacy of fenbendazole in Parascaris univalens on Swedish stud farms.

•The ascarid infecting Swedish foals has been identified as Parascaris univalens.•Resistance to pyrantel in four of eleven tested groups.•This is the first reported case of pyrantel resistance in equine ascarids in Europe.•This is the first report of anthelmintic resistance in P. univalens.