Conventional and molecular detection of Mycobacterium bovis in milk of cows and its public health hazard

Bovine tuberculosis is highly infectious zoonotic disease of economic and public health importance. The disease can transmit to human by direct contact with infected animals or by drinking unpasteurized milk and milk products. The study was performed considering the public health hazards related to elimination of Mycobacterium bovis (M.bovis) through milk of cows. 420 cows reared in private dairy farms at kalyoubia province, Egypt were examined by single intra- dermal tuberculin test and the results revealed that 1.9% (8/420) of tested animals were positive reactors. In addition to milk samples collected from tuberculin positive cows and examined by conventional methods and Polymerase Chain Reaction ( PCR) to detect M. bovis .The results showed that Acid fast bacilli by direct smear were detected in 2 (25%) of milk samples and by culturing and identification, only 1 (12.5%) of milk samples was positive for M. bovis. PCR results revealed that only one sample (12.5%) was positive. Moreover, 25 farm workers were tested by tuberculin test and the results revealed that 8% (2/25) were positive reactors, while their sputum were subjected to Acid–Fast Staining of which 1(4%) was positive and by culturing, all the examined sputum samples were negative. Our results concluded that PCR results were in concordance to that of conventional culturing but PCR is rapid and screening test for detection of M. bovis in milk. Moreover, the presence of M. bovis in milk represented a major health hazard to the herdsmen and consumers.