Serological and molecular identification of Mycobacterium avium subsp. paratuberculosis and associated risks in bovine

Discrepancies in sensitivity and specificities of tests (enzyme-linked immunoassay (ELISA) and tuberculin skin test (TST)), prevalence, and potential risk factors associated with Mycobacterium avium subsp. paratuberculosis (MAP) of bovine were hypothesized to affect its control. Keeping PCR as the gold standard test, 101 cattle and 39 buffaloes maintained at Livestock Experiment Station were tested for MAP with ELISA and TST. The incidence of MAP was 13.57% (19/140), 12.85% (18/140), and 8.57% (12/140), based on PCR, ELISA, and TST. Discrepancies in the identification of MAP in buffalo were 7.62% and 2.79% for cattle, based on ELISA compared with TST. The highest discrepancies in MAP prevalence were noted in brown buffalo (22.22%), whereas the lowest were recorded from crossbred cattle (2.63%). Status of milking was a potential risk factor (P <0.05) if MAP was identified by TST, whereas breed showed significant association (P <0.05) with MAP only on its identification by ELISA. Considerable variations were noted in the sensitivity of ELISA (94.4%) and TST (66.7%). On mutual comparisons, considering TST as a fixed diagnostic tool, the specificity and sensitivity of ELISA were 95.31% and 100%. Similarly, fixing ELISA as diagnostic tool, TST showed 100% specificity and 66.67% sensitivity. The conclusion of the study was that because of rising MAP in bovine, significant discrepancies in routine diagnostic tools, and variations in the declaration of significant risk factors, stern measures must be taken to avoid exaggerated outcomes in testing for this pathogen.