title: A comparison of the interferon gamma assay with the absorbed ELISA for the diagnosis of Johne's disease in cattle.
abstract: Two interferon gamma (IFN-gamma) assays, the IFN-gamma enzyme immunoassay (EIA) and the IFN-gamma bioassay and an absorbed ELISA were used to screen 6 cattle herds for Johne's disease. Each herd had a history of Johne's disease but the majority of infected animals did not show clinical signs. The disease status of the cattle, which were removed from the herds, was confirmed by bacteriological culture of faeces or histopathological examination and culture of tissues collected at necropsy. The sensitivities of the IFN-gamma assays and the absorbed ELISA were determined using test results from infected animals. The sensitivity of the IFN-gamma EIA in detecting subclinical (71.8 to 93.3%) and clinical animals (100%) was not significantly different. However, the IFN-gamma bioassay and the absorbed ELISA were more sensitive in detecting cattle with advanced infections (80%) than those that were subclinically affected (16.7 to 33.3%).
authors.affiliation: CSIRO Division of Animal Health, Animal Health Research Laboratory, Parkville, Victoria.
authors.forename: H
authors.initials: H
authors.lastname: Billman-Jacobe
authors.forename: M
authors.initials: M
authors.lastname: Carrigan
authors.forename: F
authors.initials: F
authors.lastname: Cockram
authors.forename: L A
authors.initials: LA
authors.lastname: Corner
authors.forename: I J
authors.initials: IJ
authors.lastname: Gill
authors.forename: J F
authors.initials: JF
authors.lastname: Hill
authors.forename: T
authors.initials: T
authors.lastname: Jessep
authors.forename: A R
authors.initials: AR
authors.lastname: Milner
authors.forename: P R
authors.initials: PR
authors.lastname: Wood
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001681:Biological Assay; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D007124:Immunoenzyme Techniques; D007371:Interferon-gamma / Q000032:analysis* / Q000096:biosynthesis; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology*; D010283:Paratuberculosis / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D000907:Antibodies, Bacterial; D007371:Interferon-gamma