Improved skin test for differential diagnosis of bovine tuberculosis by the addition of Rv3020c-derived peptides.

A peptide cocktail derived from the mycobacterial antigens ESAT-6, CFP-10, and Rv3615c allowed differentiation between Mycobacterium bovis-infected and M. bovis bacillus Calmette-Guérin (BCG)-vaccinated cattle when used as a skin test reagent for a "DIVA" test (i.e., a test capable of differentiating infected and uninfected vaccinated animals). Addition of the antigen Rv3020c improves the diagnostic sensitivity without compromising specificity in the face of BCG or Johne's disease vaccination.