Poland is one of the countries without the clinical form of paratuberculosis. Studies conducted in the north-eastern region of Poland revealed the presence of the subclinical form of the disease in cattle stock. This triggered further analyses of cattle stock infection and consumer exposure to Mycobacterium paratuberculosis (MAP). To this end, serological tests and DNA-MAP isolation from raw milk have been performed.

The study conducted in a cattle stock of over 200 cows revealed a relationship between the presence of antibodies in blood serum and the presence of DNA-MAP in milk samples.

Samples of blood serum and udder milk were taken from 103 cows over 3 years old. The ELISA (SVANOVIR™ Para-TB-Ab, Svanova) test produced 10 sero-positive results and 19 sero-doubtful ones, indicative of paratuberculosis. DNA isolation with a Qiamp DNA mini kit (Qiagen) produced a positive result in 21 samples.

9 samples were taken from animals with a sero-doubtful reaction observed in the ELISA test, while 5 - from the animals with a sero-positive reaction. The remaining 7 samples were from the animals with MAP-negative serological reaction. This confirms the periodical presence of MAP tubercles in milk, as in the case of antibodies in blood, whose level fluctuates. Analysing this relationship will contribute to better diagnostics of M.paratuberculosis infections in milk cattle stock.