Home / Fact sheets / Haemonchus contortus

Haemonchus contortus

Haemonchus contortus

Haemonchus contortus


  • Kingdom Animalia
  • Phylum Nematoda
  • Class Secernentea
  • Order Strongylida
  • Superfamily Trichostrongyloidea
  • Family Trichostrongylidae
  • Genus Haemonchus

Final host

  • Ruminants


  • Adults are easily identified because of their location in the abomasum and their large size (≈ 2-3 cm)
  • In both sexes there are cervical papillae and a tiny lancet inside the small buccal cavity
  • The female usually has a prominent vulval flap and in fresh specimens, the white ovaries wind spirally around the blood-filled intestine producing a 'barber's pole' appearance
  • The male has a well-developed bursa with large lateral lobes and an small asymmetrical dorsal lobe
  • Eggs (≈ 70-95 × 40-50 µm) are of strongyloid type, with barrel-shaped side walls, a thin and smooth shell and contain numerous blastomeres which nearly fill the entire volume when laid
  • L3 are medium-sized tailed and have 16 intestinal cells


  • Direct


  • Abomasum


  • Haematophagous


  • Eggs


  • L3