title: Evaluation of an IgG Enzyme-Linked Immunosorbent Assay as a Serological Assay for Detection of Mycoplasma bovis Infection in Feedlot Cattle.
abstract: Mycoplasma bovis is a pathogen of emerging significance in cattle throughout the world that is causing a range of diseases, including mastitis, arthritis, and pneumonia. The limited availability and efficacy of current diagnostic and prophylactic tools for its control and its increasing antimicrobial resistance are contributing to its increasing importance in beef and dairy cattle. We have developed an indirect IgG enzyme-linked immunosorbent assay (ELISA) based on a recombinant fragment of the MilA protein and have shown its potential as an effective diagnostic tool. To more comprehensively estimate the diagnostic sensitivity and specificity of this IgG ELISA for detection of infection with M. bovis in cattle and to define a suitable cutoff for use in the field, we further assessed its performance in experimentally infected calves in a closed beef herd and by applying Bayesian latent class modeling to laboratory testing results from 7,448 cattle entering Australian feedlots. The most effective cutoff points were estimated to be 68.6 antibody units (AU) for experimentally infected calves and to be 58.7 AU for a closed adult herd. Under field conditions, in feedlot cattle the globally optimal cutoff was estimated to be 105 AU. At this cutoff, the diagnostic sensitivity was 94.3% (95% probability interval [PI], 89.9% to 99.6%) with a diagnostic specificity of 94.4% (95% PI, 90.3% to 99.6%). Applying this 105 AU cutoff, 13.1% of cattle were seropositive for infection with M. bovis on entry into feedlots, and 73.5% were seropositive when followed up approximately 6 weeks later suggesting a high risk of infection shortly after entry into feedlots.
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Nadeeka K
authors.initials: NK
authors.lastname: Wawegama
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Philip F
authors.initials: PF
authors.lastname: Markham
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Anna
authors.initials: A
authors.lastname: Kanci
authors.affiliation: The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, St. Lucia, Queensland, Australia.
authors.forename: Meghan
authors.initials: M
authors.lastname: Schibrowski
authors.affiliation: Zoetis Ltd., West Ryde, New South Wales, Australia.
authors.forename: Sally
authors.initials: S
authors.lastname: Oswin
authors.affiliation: The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, St. Lucia, Queensland, Australia The University of Queensland, School of Veterinary Science, Gatton, Queensland, Australia.
authors.forename: Tamsin S
authors.initials: TS
authors.lastname: Barnes
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Simon M
authors.initials: SM
authors.lastname: Firestone
authors.affiliation: The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, St. Lucia, Queensland, Australia.
authors.forename: Timothy J
authors.identifier: 0000-0003-4573-7906
authors.initials: TJ
authors.lastname: Mahony
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia glenfb@unimelb.edu.au.
authors.forename: Glenn F
authors.identifier: 0000-0002-0903-2469
authors.initials: GF
authors.lastname: Browning
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001315:Australia; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D007074:Immunoglobulin G / Q000097:blood*; D009175:Mycoplasma Infections / Q000175:diagnosis / Q000662:veterinary*; D045682:Mycoplasma bovis / Q000276:immunology*; D012680:Sensitivity and Specificity
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G