title: Effect of paratuberculosis on the diagnosis of bovine tuberculosis in a cattle herd with a mixed infection using interferon-gamma detection assay.
abstract: Interferon-gamma (IFN-gamma) detection assay is being applied as an ancillary test to tuberculin tests in the diagnosis of bovine tuberculosis to detect the maximum number of infected animals. Among possible factors influencing the performance of tuberculosis-diagnostic tests, paratuberculosis, a widespread disease in Spain and other European countries, has been pointed out as a cause of false positive reactions. Still, its effect on the sensitivity of these tests in cattle has yet to be fully characterized. The impact of paratuberculosis in the apparent sensitivity of IFN-gamma assay was studied in a bullfighting cattle herd with a mixed tuberculosis-paratuberculosis infection, using culture of Mycobacterium bovis and Mycobacterium avium paratuberculosis as the gold standard to determine the infection status of every animal. A total of 218 animals were slaughtered and sampled for bacteriology after blood sampling. IFN-gamma assay showed a lower apparent sensitivity in animals with a mixed infection (50%) compared to all animals suffering tuberculosis (78.3%). This finding indicates that the presence of paratuberculosis in tuberculosis-infected herds could imply a serious impairment in the sensitivity of IFN-gamma detection test.
authors.affiliation: Laboratorio Visavet, Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: Alvarez
authors.forename: Lucía
authors.initials: L
authors.lastname: de Juan
authors.forename: Javier
authors.initials: J
authors.lastname: Bezos
authors.forename: Beatriz
authors.initials: B
authors.lastname: Romero
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Sáez
authors.forename: Sergio
authors.initials: S
authors.lastname: Marqués
authors.forename: Concepción
authors.initials: C
authors.lastname: Domínguez
authors.forename: Olga
authors.initials: O
authors.lastname: Mínguez
authors.forename: Baudilio
authors.initials: B
authors.lastname: Fernández-Mardomingo
authors.forename: Ana
authors.initials: A
authors.lastname: Mateos
authors.forename: Lucas
authors.initials: L
authors.lastname: Domínguez
authors.forename: Alicia
authors.initials: A
authors.lastname: Aranaz
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000276:immunology; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D007371:Interferon-gamma / Q000097:blood*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000302:isolation & purification*; D009163:Mycobacterium bovis / Q000302:isolation & purification*; D010283:Paratuberculosis / Q000150:complications* / Q000276:immunology; D012703:Serotyping; D014380:Tuberculosis, Bovine / Q000150:complications / Q000175:diagnosis* / Q000276:immunology
chemical_list: D007371:Interferon-gamma