title: Infectious agents associated with diarrhoea in neonatal foals in central Kentucky: a comprehensive molecular study.
abstract: BACKGROUND
  Diarrhoea caused by infectious agents is common in foals but there is no comprehensive molecular work-up of the relative prevalence of common agents and appearance of coinfections.
  
  
  OBJECTIVE
  To determine the prevalence of 9 infectious agents in gastrointestinal (GI)-diseased and healthy foals with ages ranging from 1 to 20 weeks of age and to what degree coinfections are associated with clinical signs of GI disease.
  
  
  METHODS
  Retrospective controlled observational study.
  
  
  METHODS
  The population consisted of 88 Thoroughbred foals aged 2 days to 17 weeks born on 32 different studfarms in Kentucky. Healthy (n = 37) and GI-diseased (n = 51) foals were identified based on clinical presentation. Faecal samples were analysed for 9 infectious agents by real-time PCR: equine rotavirus, equine coronavirus, Clostridium difficile toxins A & B, Neorickettsia risticii, Clostridium perfringens alpha toxin, Lawsonia intracellularis, Rhodococcus equi, Cryptosporidium spp., and Salmonella spp. Salmonella was also cultured from overnight selenite enrichment broth.
  
  
  RESULTS
  The prevalence of infectious pathogens under study was between 0% (Lawsonia intracellularis) and 34.6% (equine rotavirus). The overall prevalence for any infectious agent was 63.2% in the GI-diseased group and 43.2% in the healthy group. Coinfections were significantly more frequent in the sick group (15 monoinfections vs. 22 coinfections) than in the healthy group (12 vs. 4, respectively, P = 0.0002). Six of the 8 infectious agents were associated with the GI-diseased group, the other 2 were not (equine coronavirus and R. equi).
  
  
  CONCLUSIONS
  The use of panels rather than individual tests in combination with quantitative toxin gene analysis enables detection of coinfections significantly associated with risk of disease. Several infectious diseases previously not tested for or considered unimportant were found at high prevalence and require further investigation.
authors.affiliation: Hagyard Equine Medical Institute, Kentucky, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Slovis
authors.forename: J
authors.initials: J
authors.lastname: Elam
authors.forename: M
authors.initials: M
authors.lastname: Estrada
authors.forename: C M
authors.initials: CM
authors.lastname: Leutenegger
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D003457:Cryptosporidiosis / Q000453:epidemiology / Q000469:parasitology*; D003967:Diarrhea / Q000662:veterinary*; D006734:Horse Diseases / Q000453:epidemiology / Q000209:etiology*; D006736:Horses; D007629:Kentucky / Q000453:epidemiology; D014777:Virus Diseases / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology
keywords: Cryptosporidium; coinfection; diarrhoea; equine coronavirus; foal; horse; infectious; real-time PCR