Figure 3From: Experimental infection of lambs with C and S-type strains of Mycobacterium avium subspecies paratuberculosis: immunological and pathological findingsResponse to the intradermal skin test (IDT). The results are expressed as the skin-fold thickness increase (in mm) after intradermal injection of avian PPD, at 120 and 360 dpi in the five experimental groups. Error bars: standard deviation.Back to article page