EN
Paratuberculosis is a chronic, ulcerating enteritis induced by Mycobacterium avium subsp. paratuberculosis (MAP). It affects domesticated and wild ruminants throughout the world and causes significant economic losses. The opinion that the eradication of tuberculosis has resulted in the elimination of MAP-infected animals and that the disease no longer occurs in Poland, together with difficulties in the diagnosis of the disease, often complicated by other afflictions, the long period of its development and its dubious clinical picture, cause that herd infection might remain unrecognized for a number of years. Dyspepsia proceeding with periodical watery diarrhea was observed on a farm with 250 dairy cows located in Żuławy Wiślane, in the north-eastern region of Poland. By the elimination of epizootic diseases, the conclusion was that the most probable cause of the disease is paratuberculosis. It was proved by the serological tests of cows with clinical symptoms and cows which had manifested symptoms earlier. All blood samples from cows with clinical symptoms and two samples from clinically healthy cows had positive results for paratuberculosis. The subsequent serological test showed that 8.6% of the herd population was infected by MAP. An autopsy performed instantly after anaesthetizing the animals with clinical symptoms showed changes typical for paratuberculosis. Regular examination, the isolation and elimination of infected animals, as well protection of new born calves should be the method used to restrain paratuberculosis in the herd. It could be useful to certify the herds and transport the animals only between farms free from paratuberculosis.