title: Factors associated with likelihood of horses having a high serum Streptococcus equi SeM-specific antibody titer.
abstract: OBJECTIVE
  To identify factors associated with an increased likelihood that horses would have a serum Streptococcus equi SeM-specific antibody titer > or = 1:1,600.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  188 healthy client-owned horses.
  
  
  METHODS
  A single serum sample from each horse was tested for SeM-specific antibody titer with an ELISA. Multivariate logistic regression was used to identify factors associated with having a titer > or = 1:1,600.
  
  
  RESULTS
  Age, breed, and vaccination status were significantly associated with the likelihood of having a titer > or = 1:1,600. The odds of having a titer > or = 1:1,600 increased by a factor of 1.07 with each 1-year increase in age. Quarter Horses and horses of other breeds were 4.08 times as likely as were Thoroughbreds and warmbloods to have a titer this high. Horses that had previously received an intranasal S equi vaccine were 4.7 times as likely as were horses without any history of vaccination to have a titer this high.
  
  
  CONCLUSIONS
  Results indicated that older horses, horses other than Thoroughbreds and warmbloods, and horses that had been vaccinated with an attenuated-live intranasal S equi vaccine between 1 and 3 years previously had an increased likelihood of having a serum SeM-specific antibody titer > or = 1:1,600.
authors.affiliation: Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA 19348, USA. boylea@vet.upenn.edu
authors.forename: Ashley G
authors.initials: AG
authors.lastname: Boyle
authors.forename: Corinne R
authors.initials: CR
authors.lastname: Sweeney
authors.forename: Michaela
authors.initials: M
authors.lastname: Kristula
authors.forename: Ray
authors.initials: R
authors.lastname: Boston
authors.forename: Gary
authors.initials: G
authors.lastname: Smith
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000918:Antibody Specificity; D005260:Female; D006734:Horse Diseases / Q000276:immunology*; D006736:Horses; D016015:Logistic Models; D008297:Male; D012307:Risk Factors; D013290:Streptococcal Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary; D022541:Streptococcal Vaccines / Q000276:immunology; D018502:Streptococcus equi / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D022541:Streptococcal Vaccines