Bovine tuberculosis is significant infectious disease that produces large economic losses as well as is considered one of the major public health concerns. Therefore, there is an urgent need for improved methods to combat bovine tuberculosis. Skin testing with tuberculin and slaughter of test-positive cattle has been the mainstay of national eradication programmes for
many years. However, new tools, including additional diagnostic methods, are required in countries where skin testing has not led to full eradication. Diagnostic blood tests are now available, e.g. the gamma interferon (γ-IFN) assay, which uses an ELISA as the detection method for interferon. In this study, 5700 cattle representing different 15 dairy farms were
examined by the single intradermal comparative tuberculin skin test (SICTT). Both positive and suspected animals were tested for serum γ-IFN. Our finding revealed very high correlation between SICTT and γ-IFN testing results where γ-IFN showed 98.3% positive out of total 121 animals were positive for SICTT. Moreover, 35 animals that were suspected by
SICTT, demonstrated positive results in 33 animals (94%) when their sera tested for γ-IFN. Interestingly, these suspected animals when retested by skin test after 60 days; they showed 30 positive reactor cattle. Thereby, it was concluded that use of γ-IFN in surveillance for TB in cattle farms is reliable, time-consuming test and can minimize dissemination of infections
that could be resulted when keeping many suspected animals for months until retesting.