Trichostrongylus axei (Hair Worms)

What you need to know

Eggs hatch when they are eaten by the horse. Larvae migrate to the stomach and mature. Adult worms in the stomach and in the small intestine irritate and erode the villi, or finger-like projections, of the gut, damaging the capillaries and lymph vessels. Eggs are laid and passed in the dung. Hair worm larvae are swallowed as your horse eats infected grass. When damaged, villi are unable to digest and absorb nutrients properly. Dark, foul-smelling diarrhoea may result. Severe damage can cause bleeding into the intestine, leading to anaemia and loss of condition. Foals are particularly susceptible to hair worm infection.

Effective wormer chemicals: Ivermectin, Moxidectin

More information

Trichostrongylus sp. The small stomach worm (hairworm) of horses, Trichostrongylus axei , is also found in ruminants ( Haemonchus, Ostertagia, and Trichostrongylus spp) and, consequently, is generally only a clinical problem in horses co-mingled or rotated on pasture with ruminants. Adult T axei are slender and measure up to 8 mm long. Haemonchus, Ostertagia, and Trichostrongylus spp Details of the life cycle in Equidae have not been carefully studied, but it is known that the larvae penetrate the mucosa. These worms produce a chronic catarrhal gastritis, which may result in weight loss. The lesions comprise nodular areas of thickened mucosa surrounded by a zone of congestion and covered with a variable amount of mucus. The lesions may be rather small and irregularly circumscribed, or they may coalesce and involve most or all of the glandular portion of the stomach, and erosions and ulcerations may be seen.