Comparative analysis of intradermal tuberculin test and γ-interferon assay for diagnosis of bovine tuberculosis

Abstract

The present study was carried out in and around Anand district of Gujarat with the aim to assess the sensitivity and specificity of IFN-γ assay as compared to intradermal tuberculin test for diagnosis of bovine tuberculosis during the period 2011-12. The prevalence of bovine TB in the cattle was 26.19% by TST and 38.49% by IFN- γ assay. Breed wise, highest prevalence of bovine TB was found in Gir (38.96%), followed by Triple cross (23.95%) and Kankrej (16.45%) by TST; while by IFN- γ assay, highest prevalence was observed in Triple cross (42.70%). Age wise, highest prevalence of bovine TB was found in adults (37.90%) followed by calves (26.66%) and heifers (11.22%) by TST; while by IFN-γ assay, highest prevalence was observed in calves (66.66%) followed by adults (44.35%) and heifers (22.44%). Sex wise, more prevalence of bovine TB was found in males (56.25%) than in females (21.81%) by TST; while by IFN-γ assay, more prevalence was observed in females (39.25%) than in males (31.25%). Sensitivity and specificity of TST in detecting bovine TB were 27.27% and 57.52% respectively, compared to IFN-γ assay. ELISPOT assay showed 34.78% animals were found positive for bovine TB. IFN-γ assay showed better sensitivity in detecting bovine TB at younger age compared to TST, and hence can be useful in timely removal of the infected animals from the herd.

Keywords

• Bovine tuberculosis, ELISPOT, IFN-γ, Tuberculin test