title: Performance of five serological assays for diagnosis of Rhodococcus equi pneumonia in foals.
abstract: The performance of four enzyme-linked immunosorbent assays (ELISAs) (ELISA-6939, ELISA-33701, ELISA-VapA, and ELISA-California) and an agar gel immunodiffusion test for diagnosis of Rhodococcus equi pneumonia in foals was evaluated. Antibody concentrations of foals with culture-confirmed R. equi pneumonia (n = 41) were compared to those of age-matched pasturemates that remained clinically healthy during the entire breeding season (n = 24). For each serological assay evaluated, selection of a low cutoff resulted in high sensitivity but low specificity. Increasing the cutoff value resulted in better specificity but to the detriment of sensitivity. The best diagnostic performance was achieved with ELISA-California at a cutoff of 40%, resulting in a sensitivity of 59% and a specificity of 88%. We conclude that current serological assays do not differentiate between diseased and clinically healthy foals.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610, USA. gigueres@mail.vetmed.ufl.edu
authors.forename: Steeve
authors.initials: S
authors.lastname: Giguère
authors.forename: Jorge
authors.initials: J
authors.lastname: Hernandez
authors.forename: Jack
authors.initials: J
authors.lastname: Gaskin
authors.forename: John F
authors.initials: JF
authors.lastname: Prescott
authors.forename: Shinji
authors.initials: S
authors.lastname: Takai
authors.forename: Corey
authors.initials: C
authors.lastname: Miller
mesh_terms: D000193:Actinomycetales Infections / Q000175:diagnosis* / Q000276:immunology / Q000662:veterinary*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D019540:Area Under Curve; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006734:Horse Diseases / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology*; D006736:Horses; D005779:Immunodiffusion; D016929:Rhodococcus equi / Q000276:immunology / Q000302:isolation & purification*; D012680:Sensitivity and Specificity
chemical_list: D000907:Antibodies, Bacterial