title: An ultrasonographic scoring method for transabdominal monitoring of ascarid burdens in foals.
abstract: BACKGROUND
  Parascaris spp. infections can lead to life-threatening small intestinal impactions in foals. Currently available diagnostic techniques cannot estimate the magnitude of an ascarid burden, and hence identify foals potentially at risk of developing impactions.
  
  
  OBJECTIVE
  To describe and evaluate an ultrasonographic transabdominal scoring technique for monitoring of ascarid burdens in foals and to perform a cost-benefit analysis of the application of this technique.
  
  
  METHODS
  A transabdominal ultrasonographic technique was validated against ascarid worm counts from 10 foals aged 162-294 days. In a treatment trial, 15 foals were randomly allocated to 3 treatment groups: ivermectin, oxibendazole and no treatment. Blinded ultrasound examinations were performed daily for 5 consecutive days following treatment. Foals were examined ultrasonographically twice by the same investigator, and by different investigators for intra- and interobserver agreement evaluation. Cost-benefit analyses identified threshold values for the probability of ascarid impactions above which the screening method becomes cost-effective.
  
  
  METHODS
  The ultrasound technique used 3 locations along the ventral midline. An ascarid scoring system was established that assessed the magnitude of ascarid burden ranging from 1-4. The method was validated against worm burdens of 10 worms and above with calculation of diagnostic specificity, sensitivity, and predictive values. Treatment trial data were evaluated statistically using mixed model analysis. Kappa values were generated for intra- and interobserver agreement.
  
  
  RESULTS
  Two consecutive examinations were found to detect worm burdens >10 ascarids reliably. Ascarid scores declined in response to both anthelmintic treatments, although differences were not statistically significant. Kappa values indicated fair to moderate intra- and interobserver agreements. The majority of cost-benefit analyses indicated that ultrasound examinations are cost effective when the probability of ascarid impactions is above a range of 0.0001-0.0082 (i.e. 1 in 10,000 to 8 in 1000 foals).
  
  
  CONCLUSIONS
  The ultrasonographic screening techniques can be a useful tool for monitoring ascarid burdens in foals.
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 Veterinary Science, M.H. Gluck Equine Research Center, University of Kentucky, Lexington, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Donoghue
authors.affiliation: Department of Veterinary Science, M.H. Gluck Equine Research Center, University of Kentucky, Lexington, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Stephens
authors.affiliation: Department of Agricultural Economics, University of Kentucky, Lexington, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Stowe
authors.affiliation: Zoetis Outcomes Research, Reidsville, North Carolina, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Donecker
authors.affiliation: Equine Integrated Medicine, Georgetown, Kentucky, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Fenger
mesh_terms: D000818:Animals; D017191:Ascaridida Infections / Q000000981:diagnostic imaging / Q000662:veterinary*; D001199:Ascaridoidea; D005260:Female; D006734:Horse Diseases / Q000000981:diagnostic imaging / Q000469:parasitology*; D006736:Horses; D007411:Intestinal Diseases, Parasitic / Q000000981:diagnostic imaging / Q000662:veterinary*; D008297:Male; D008991:Monitoring, Physiologic / Q000662:veterinary; D014463:Ultrasonography / Q000379:methods / Q000662:veterinary*
keywords: Parascaris; cost-benefit; diagnosis; horse; screening; ultrasonography