Partial protection of lambs against Haemonchus contortus by vaccination with a fractionated preparation of the parasite.
Florida Native lambs, less than 6 months of age, were successfully vaccinated against Haemonchus contortus with a high mol. wt fraction (greater than 30,000 daltons) derived from a somatic extract of H. contortus larvae (SEL) and excretions and secretions (ES) of larvae isolated during in vitro development from the infective 3rd to 4th stage. A 59% reduction in adult worm numbers was obtained in vaccinates compared to naive lambs following challenge. The protection in vaccinated lambs was similar to that seen in lambs exposed to a primary infection of H. contortus larvae which had been cleared with anthelmintic prior to the challenge infection. The unfractionated SEL/ES preparation and a low mol. wt fraction gave no significant protection against challenge infection.
D000818:Animals; D000917:Antibody Formation; D004797:Enzyme-Linked Immunosorbent Assay; D006188:Haemonchiasis / Q000276:immunology / Q000662:veterinary*; D006189:Haemonchus / Q000276:immunology*; D007814:Larva / Q000276:immunology; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology*; D014251:Trichostrongyloidea / Q000276:immunology*; D014252:Trichostrongyloidiasis / Q000662:veterinary*; D014611:Vaccination / Q000662:veterinary*