Intradermal comparative cervical tuberculin test in the diagnosis of caprine tuberculosis

Tuberculosis remains one of the most important infectious diseases with well-known zoonotic nature that affect humans, wildlife, and domestic animals, including goats. Nonetheless, no intradermal tuberculin test has been standardized for caprine diagnosis of tuberculosis. The present study investigated the intradermal comparative cervical tuberculin test (ICCTT) in the diagnosis of tuberculosis among 60 goats from farms with history of tuberculosis. The cutoff applied to goats was based on a study where goats had been experimentally infected with Mycobacterium bovis and Mycobacterium avium . Clinical examination, bacteriological culture, and histopathological staining were assessed to the diagnosis. Isolates compatible with mycobacteria were subjected for molecular diagnosis based on gyrB -restriction fragment length polymorphism (RFLP) analysis and PCR restriction-enzyme analysis (PRA) of hsp 65 gene by BstEII and HaeIII, namely PRA- hsp 65 assay. From all goats, 60% ( n = 36/60), 3.3% ( n = 2/60), and 36.7% ( n = 22/60) showed positive, inconclusive, and negative reactions, respectively. Out of 36 goats with ICCTT positive, 75% ( n = 27/36) had isolation of mycobacteria and were detected M. bovis by gyr B-RFLP. Molecular diagnosis and histopathological findings compatible with tuberculosis showed 86.1% ( n = 31/36) concordance with the ICCTT. When compared ICCTT with M. bovis isolation, gyrB -RFLP, and histopathology, the better arithmetic means of sensitivity and specificity were 2.5 mm for ICCTT compared with M. bovis isolation and gyrB -RFLP, and 4.55 mm when compared with histopathology. Both receiver operating characteristic (ROC) curves presented statistical significance ( P