title: Evaluation of specificity of tuberculosis diagnostic assays in caprine flocks under different epidemiological situations.
abstract: The aim of this study was to evaluate the specificity of the most widely used tuberculosis (TB) diagnostic tests, single intradermal tuberculin (SIT) and single comparative intradermal tuberculin (SCIT) tests and interferon-gamma (IFN-γ) assay in 937 animals from eight TB-free caprine flocks under different epidemiological situations. Maximum specificity was found using SCIT test (99.4-100% depending on the interpretation criteria) while SIT test and IFN-γ assay showed a slightly lower overall specificity (97.6-99.2% and 96.4-98.4% respectively). Specificity of the SIT test in a Corynebacterium pseudotuberculosis infected flock was significantly (P<0.05) lower if a severe interpretation criterion was applied. Similarly, specificity values of SIT test and particularly IFN-γ assay in a paratuberculosis (PTB)-vaccinated flock were lower than those observed in non-vaccinated flocks. Higher proportion of false positive reactors to TB tests (SIT and IFN-γ assay) were observed among animals positive in the PTB-ELISA in PTB vaccinated flock. These results demonstrate that TB diagnostic tests show an adequate specificity when performed in goats from TB-free flocks in most situations. However, certain factors such as C. pseudotuberculosis infection and paratuberculosis vaccination can have a negative impact in the most sensitive tests.
authors.affiliation: Centro VISAVET, Universidad Complutense de Madid, 28040 Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Bezos
authors.forename: Julio
authors.initials: J
authors.lastname: Álvarez
authors.forename: Olga
authors.initials: O
authors.lastname: Mínguez
authors.forename: Sergio
authors.initials: S
authors.lastname: Marqués
authors.forename: Olegario
authors.initials: O
authors.lastname: Martín
authors.forename: Virginia
authors.initials: V
authors.lastname: Vigo
authors.forename: Carmen
authors.initials: C
authors.lastname: Pieltain
authors.forename: Beatriz
authors.initials: B
authors.lastname: Romero
authors.forename: Sabrina
authors.initials: S
authors.lastname: Rodríguez
authors.forename: Carmen
authors.initials: C
authors.lastname: Casal
authors.forename: Ana
authors.initials: A
authors.lastname: Mateos
authors.forename: Lucas
authors.initials: L
authors.lastname: Domínguez
authors.forename: Lucía
authors.initials: L
authors.lastname: de Juan
mesh_terms: D000818:Animals; D015511:Goat Diseases / Q000175:diagnosis* / Q000453:epidemiology; D006041:Goats; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology; D014374:Tuberculin Test / Q000592:standards / Q000662:veterinary*; D014376:Tuberculosis / Q000175:diagnosis / Q000662:veterinary*