Abstract

Nematodirus helvetianus May 1920 (Nematoda: Molineidae) is a parasitic nematode from the small intestine of several species of ruminants in temperate climates around the world and is being recognized as the most pathogenic species of the genus in cattle. Finding of the nematodes was made by applying the necropsy protocol described by Withlock in 100 cattle between 0.5 to 2.5 years old from several locations of La Araucanía in southern Chile. Based on the morphology of the reproductive system of males, the presence of N. helvetianus in 2% (2/100) of cattle was found with an estimated total number of 165 (5 x 33) specimens of the parasite. Nematodes were cleared in lactophenol and mounted in glycerol-gelatin. Measurements including the morphology of the spicules corresponded with differential characteristics proposed for discrimination and identification of the species. The present results constitute the first record of N. helvetianus in cattle from Chile, contribute new information on helminths of ruminants in this geographical location