title: Development of Strongylus vulgaris-specific serum antibodies in naturally infected foals.
abstract: Strongylus vulgaris is regarded as the most pathogenic helminth parasite infecting horses. Migrating larvae cause pronounced endarteritis and thrombosis in the cranial mesenteric artery and adjacent branches, and thromboembolism can lead to ischemia and infarction of large intestinal segments. A recently developed serum ELISA allows detection of S. vulgaris-specific antibodies during the six-month-long prepatent period. A population of horses has been maintained at the University of Kentucky without anthelmintic intervention since 1979, and S. vulgaris has been documented to be highly prevalent. In 2012, 12 foals were born in this population, and were studied during a 12-month period (March-March). Weekly serum samples were collected to monitor S. vulgaris specific antibodies with the ELISA. Nine colts underwent necropsy at different time points between 90 and 300 days of age. At necropsy, Strongylus spp. and Parascaris equorum were identified to species and stage and enumerated. Initial statistical findings indicate a significant interaction between foal age and ELISA results (p<0.042). All foals had initial evidence of S. vulgaris-directed maternal antibodies transferred in the colostrum, but then remained ELISA negative during their first three months of life. Foals born in February and March became ELISA positive at about 12 weeks of age, while those born in April and May went positive at about 15 and 21 weeks, respectively. Foal date of birth was significantly associated with ELISA results (p<0.0001). This could be explained by birth date-dependent differences in parasite exposure. One foal remained ELISA-negative throughout the course of 30 weeks during the study. A significant association was found between ELISA values and larval S. vulgaris burdens (p<0.0001) as well as a three-way interaction between S. vulgaris, S. edentatus, and P. equorum burdens (p<0.001). A plateau with a subsequent decline in ELISA values corresponded with S. vulgaris larvae leaving the bloodstream and migrating back to the intestine.
authors.affiliation: M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, United States. Electronic address: martin.nielsen@uky.edu.
authors.forename: M K
authors.initials: MK
authors.lastname: Nielsen
authors.affiliation: Department of Statistics, George Mason University, Fairfax, VA, United States.
authors.forename: A N
authors.initials: AN
authors.lastname: Vidyashankar
authors.affiliation: M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, United States.
authors.forename: H S
authors.initials: HS
authors.lastname: Gravatte
authors.affiliation: M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, United States.
authors.forename: J
authors.initials: J
authors.lastname: Bellaw
authors.affiliation: M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, United States.
authors.forename: E T
authors.initials: ET
authors.lastname: Lyons
authors.affiliation: Department of Large Animal Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: U V
authors.initials: UV
authors.lastname: Andersen
mesh_terms: D000367:Age Factors; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood* / Q000276:immunology; D001158:Arteries / Q000469:parasitology; D001199:Ascaridoidea / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006736:Horses; D007422:Intestines / Q000469:parasitology; D007814:Larva; D008297:Male; D059208:Parasite Load; D013319:Strongyle Infections, Equine / Q000276:immunology* / Q000469:parasitology*; D013323:Strongylus / Q000276:immunology*; D013995:Time
chemical_list: D000909:Antibodies, Helminth
keywords: ELISA; Foals; Sero-conversion; Strongylus vulgaris