title: Nonstrangulating intestinal infarction associated with Strongylus vulgaris in referred Danish equine cases.
abstract: BACKGROUND
  Strongylus vulgaris is a pathogenic helminth parasite infecting horses and was once considered to be the primary cause of colic. Migrating larvae cause ischaemia and infarction of intestinal segments. This knowledge is derived from case reports and experimental inoculations of parasite-naïve foals, and it remains unknown to what extent the parasite is associated with different types of colic.
  
  
  OBJECTIVE
  To evaluate the role of S. vulgaris as a risk factor for different types of colic in horses.
  
  
  METHODS
  A retrospective case-control study among horses referred with abdominal pain to the University of Copenhagen Large Animal Teaching Hospital during 2009-2011.
  
  
  METHODS
  Each colic case was matched with an equid of the same type (pony, Warmblooded or Coldblooded), age, sex and admitted in the same month and year but for problems unrelated to the gastrointestinal tract. Serum samples were analysed for antibodies to migrating S. vulgaris larvae using a recently developed enzyme-linked immunosorbent assay (ELISA). The following 4 case definitions were used: colic sensu lato, i.e. all horses presenting with colic (n = 274), with further subgroups, i.e. undiagnosed colics (n = 48), strangulating obstructions (n = 76) and nonstrangulating infarctions (n = 20).
  
  
  RESULTS
  Strongylus vulgaris antibody levels were similar to control values in colics sensu lato and horses with undiagnosed colic. In contrast, nonstrangulating intestinal infarctions were significantly associated with positive S. vulgaris ELISAs (odds ratio 5.33, 95% confidence interval 1.03-27.76, P = 0.05). Also, horses with nonstrangulating infarctions had a significantly higher occurrence of positive ELISAs than horses with strangulating obstructions (odds ratio 3.79, 95% confidence interval 1.34-10.68, P = 0.01) and the colic sensu lato group (odds ratio 3.09, 95% confidence interval 1.20-8.01, P = 0.02).
  
  
  CONCLUSIONS
  Nonstrangulating intestinal infarction was strongly associated with S. vulgaris-specific antibodies, whereas the more broadly defined colic categories were not associated with positive ELISA results. Thus, the ELISA holds potential to become a helpful adjunct in diagnosis and management of horses with colic.
authors.affiliation: Department of Veterinary Science, M.H. Gluck Equine Research Center, University of Kentucky, Lexington, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Nielsen
authors.affiliation: Department of Large Animal Sciences, University of Copenhagen, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Jacobsen
authors.affiliation: Department of Large Animal Sciences, University of Copenhagen, Denmark.
authors.forename: S N
authors.initials: SN
authors.lastname: Olsen
authors.affiliation: Virbac, Carros, France.
authors.forename: E
authors.initials: E
authors.lastname: Bousquet
authors.affiliation: Department of Large Animal Sciences, University of Copenhagen, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Pihl
mesh_terms: D000818:Animals; D003085:Colic / Q000209:etiology / Q000473:pathology / Q000662:veterinary; D003718:Denmark / Q000453:epidemiology; D006734:Horse Diseases / Q000453:epidemiology / Q000469:parasitology* / Q000473:pathology; D006736:Horses; D007238:Infarction / Q000453:epidemiology / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D007411:Intestinal Diseases, Parasitic / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D017206:Strongylida Infections / Q000150:complications / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D013323:Strongylus / Q000145:classification*
keywords: Strongylus vulgaris; colic; enzyme-linked immunosorbent assay; horse; intestinal infarction; odds ratio