title: Serial use of serologic assays and fecal PCR assays to aid in identification of subclinical Lawsonia intracellularis infection for targeted treatment of Thoroughbred foals and weanlings.
abstract: OBJECTIVE
  To assess the serial use of serum immunoperoxidase monolayer assays (IPMAs) and fecal PCR assays, combined with other diagnostic methods, to identify subclinical Lawsonia intracellularis infections for targeted treatment of Thoroughbred foals and weanlings at farms in which the pathogen was endemic or nonendemic.
  
  
  METHODS
  Evaluation study.
  
  
  METHODS
  100 foals and weanlings (53 and 47 at farms in which L intracellularis was endemic and nonendemic, respectively).
  
  
  METHODS
  Serum was collected every 4 weeks and tested via IPMA, for antibodies against L intracellularis. Fecal samples were collected every 2 weeks and tested by use of an L intracellularis-specific PCR assay. When results for IPMAs or PCR assays were positive or clinical signs compatible with equine proliferative enteropathy (EPE) were detected, clinicopathologic testing was performed to determine treatment.
  
  
  RESULTS
  No foals had positive results for the L intracellularis-specific IPMA until after weaning; 32 of 53 (60.4%) weanlings at the farm in which L intracellularis was endemic and 8 of 47 (170%) at the farm in which L intracellularis was nonendemic had positive IPMA results, whereas the number of weanlings that tested positive via fecal PCR assays at those farms was 6 and 0, respectively. Nineteen of 32 weanlings with positive IPMA results at the farm in which L intracellularis was endemic were treated for EPE; 5 of these had clinical signs of EPE. No weanlings at the nonendemic farm had clinical signs of or were treated for EPE.
  
  
  CONCLUSIONS
  IPMA appeared to be a useful means of identifying weanlings exposed to L intracellularis.
authors.affiliation: Hagyard Equine Medical Institute, 4250 Iron Works Pike, Lexington, KY 40511.
authors.forename: Allen E
authors.initials: AE
authors.lastname: Page
authors.forename: Nathan M
authors.initials: NM
authors.lastname: Slovis
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Gebhart
authors.forename: Karen
authors.initials: K
authors.lastname: Wolfsdorf
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Mapes
authors.forename: Nicola
authors.initials: N
authors.lastname: Pusterla
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000907:Antibodies, Bacterial / Q000097:blood; D045824:Desulfovibrionaceae Infections / Q000175:diagnosis / Q000662:veterinary*; D003937:Diagnosis, Differential; D005243:Feces / Q000382:microbiology; D005260:Female; D006734:Horse Diseases / Q000175:diagnosis*; D006736:Horses; D020639:Lawsonia Bacteria / Q000276:immunology / Q000302:isolation & purification; D008297:Male; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D012698:Serologic Tests / Q000662:veterinary*
chemical_list: D000907:Antibodies, Bacterial