Introduction.

It is known that bacteria from Corynebacterium and Mycobacterium genus have some antigenic determinants in common and therefore serological cross-reactions may occur. In this study serological reactions in paratuberculosis and pseudotuberculosis infected flock were compared.

Material and methods.

In the flock where paratuberculosis and pseudotuberculosis were confirmed bacteriologically, sera of 519 animals were tested. For the detection of antibodies against Mycobacterium avium subsp. paratuberculosis commercial ELISA kit (IDEXX, Sweden) was used whereas for pseudotuberculosis serology ELISA was developed in our laboratory.

Results and discussion.

In paratuberculosis test 38 samples were positive and 17 were doubtful. 42 samples were positive in pseudotuberculosis test (7 of them highly positive) whereas 60 samples were doubtful. Among 42 pseudotuberculosis positive sera 43% were positive and 14% were doubtful in paratuberculosis test. The percent of paratuberculosis positive animals was increased in cases of pseudotuberculosis highly positive sera to 71%. In pseudotuberculosis doubtful sera 10% were paratuberculosis positive whereas in pseudotuberculosis negative sera only 3% were paratuberculosis positive. Our results suggest that special care should be taken by interpretation of paratuberculosis positive serology in the flocks infected with Corynebacterium pseudotuberculosis.
The work was supported by Ministry of Agriculture, Forestry and Food of the Republic of Slovenia.