title: Effect of an inactivated paratuberculosis vaccine on the intradermal testing of goats for tuberculosis.
abstract: The effect of an inactivated paratuberculosis vaccine on the diagnosis of tuberculosis (TB) in goats was investigated in a herd with a history of clinical paratuberculosis but which was free of TB. Cohorts of animals in 2006, 2008 and 2009, were vaccinated once at 1 month of age, and 50% of the 2006 cohort served as unvaccinated controls. The goats were aged 8 months, 20 months and 3.5 years old at the time of the survey. All animals were assessed using a single intradermal injection of bovine tuberculin purified protein derivative (PPD) (SID test), or using both bovine and avian PPD (CID test). An interferon (IFN)-γ assay using both bovine and avian PPD was carried out on the 2006 cohort and was interpreted according to three different 'cut-off' points. No unvaccinated (control) animals tested positive to any of the assays, confirming that the herd was TB-free. The SID test had a low specificity in vaccinated animals at 8 and 20 months of age, whereas the CID test demonstrated 100% specificity in animals ≥20 months-old. The specificity of IFN-γ assay was less than maximal for vaccinated animals 3.5 years old as small numbers of false positives were detected, although this depended on the chosen cut-off point. The study findings demonstrate that the use of an inactivated paratuberculosis vaccine in goats <1 month-old in a TB-free herd does not result in false positives to a CID test for TB when performed in animals ≥20 months-old.
authors: ONIRIS, UMR 1300 Bio-agression, Epidémiologie et Analyse de Risque en Santé Animale, 44307 Nantes, France. christophe.chartier@oniris.fr
authors: Christophe
authors: C
authors: Chartier
authors: Pascale
authors: P
authors: Mercier
authors: Marie-Pierre
authors: MP
authors: Pellet
authors: Jaquemine
authors: J
authors: Vialard
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology*; D005189:False Positive Reactions; D015511:Goat Diseases / Q000517:prevention & control*; D006041:Goats; D007428:Intradermal Tests / Q000662:veterinary; D010283:Paratuberculosis / Q000517:prevention & control*; D014374:Tuberculin Test / Q000662:veterinary*; D015164:Vaccines, Inactivated
chemical_list: D001428:Bacterial Vaccines; D015164:Vaccines, Inactivated