A strongyle is a parasitic roundworm of the family Strongylidae, related to the hookworms, it infests the intestinal tract of mammals — particularly horses, but also ruminants and other livestock. The worms attach to the gut wall and feed on blood and tissue, and their larvae migrate through the body, causing damage along the way. Heavy infestations lead to weight loss, anaemia, diarrhoea, and poor condition, and in horses the migrating larvae can cause serious arterial damage. Control depends on pasture management — resting and rotating grazing — and strategic use of anthelmintic wormers, with faecal egg counts guiding treatment to slow drug resistance. Strongyles are a veterinary rather than a human food-safety concern.