title: Serological diagnosis of bovine neosporosis: a Bayesian evaluation of two antibody ELISA tests for in vivo diagnosis in purchased and abortion cattle.
abstract: Currently, there are no perfect reference tests for the in vivo detection of Neospora caninum infection. Two commercial N caninum ELISA tests are currently used in Belgium for bovine sera (TEST A and TEST B). The goal of this study is to evaluate these tests used at their current cut-offs, with a no gold standard approach, for the test purpose of (1) demonstration of freedom of infection at purchase and (2) diagnosis in aborting cattle. Sera of two study populations, Abortion population (n=196) and Purchase population (n=514), were selected and tested with both ELISA's. Test results were entered in a Bayesian model with informative priors on population prevalences only (Scenario 1). As sensitivity analysis, two more models were used: one with informative priors on test diagnostic accuracy (Scenario 2) and one with all priors uninformative (Scenario 3). The accuracy parameters were estimated from the first model: diagnostic sensitivity (Test A: 93.54 per cent-Test B: 86.99 per cent) and specificity (Test A: 90.22 per cent-Test B: 90.15 per cent) were high and comparable (Bayesian P values >0.05). Based on predictive values in the two study populations, both tests were fit for purpose, despite an expected false negative fraction of ±0.5 per cent in the Purchase population and ±5 per cent in the Abortion population. In addition, a false positive fraction of ±3 per cent in the overall Purchase population and ±4 per cent in the overall Abortion population was found.
authors: Unit Coordination of Veterinary Diagnosis & Epidemiology and Risk analysis (CDD-ERA), Operational Directorate of Surveillance and Interactions, Veterinary and Agrochemical Research Centre (CODA-CERVA), Groeselenberg, 99, Brussels B-1180, Belgium.
authors: S
authors: S
authors: Roelandt
authors: Unit Coordination of Veterinary Diagnosis & Epidemiology and Risk analysis (CDD-ERA), Operational Directorate of Surveillance and Interactions, Veterinary and Agrochemical Research Centre (CODA-CERVA), Groeselenberg, 99, Brussels B-1180, Belgium Laboratory of Veterinary Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors: Y
authors: Y
authors: Van der Stede
authors: Unit of Porcine Production, Association Régionale de Santé & d' Identification Animales (ARSIA), Loncin, Belgium.
authors: G
authors: G
authors: Czaplicki
authors: Unit Health Care (Bovine), Dierengezondheidszorg Vlaanderen (DGZ), Torhout, Belgium.
authors: H
authors: H
authors: Van Loo
authors: Unit Health Care (Bovine), Dierengezondheidszorg Vlaanderen (DGZ), Torhout, Belgium.
authors: E
authors: E
authors: Van Driessche
authors: Veterinary Epidemiology Unit, Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors: J
authors: J
authors: Dewulf
authors: Directorate Control and Policy, Federal Agency for Safety of the Food Chain, Brussels, Belgium.
authors: J
authors: J
authors: Hooyberghs
authors: Interuniversity Institute for Biostatistics and statistical Bioinformatics (I-BioStat), Hasselt University, Diepenbeek, Belgium.
authors: C
authors: C
authors: Faes
mesh_terms: D000034:Abortion, Veterinary; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D001499:Bayes Theorem; D001530:Belgium / Q000453:epidemiology; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D003048:Coccidiosis / Q000175:diagnosis / Q000662:veterinary*; D003132:Commerce; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D018688:Neospora / Q000302:isolation & purification*; D011247:Pregnancy; D016036:Seroepidemiologic Studies
chemical_list: D000913:Antibodies, Protozoan
keywords: Diagnostics; ELISA; Epidemiology; Modelling; Neospora; Statistics