title: Infectivity of Haemonchus contortus in sheep after freezing for ten years over liquid nitrogen.
mesh_terms: D000818:Animals; D005615:Freezing; D006189:Haemonchus / Q000472:pathogenicity* / Q000502:physiology; D009068:Movement; D009584:Nitrogen; D010270:Parasite Egg Count; D011309:Preservation, Biological / Q000379:methods*; D012756:Sheep / Q000469:parasitology*; D013997:Time Factors; D014251:Trichostrongyloidea / Q000472:pathogenicity*
chemical_list: D009584:Nitrogen