PARATUBERCULOSIS - A PREVALENCE STUDY IN THE PLATEAU-DE-DIESSE

We analysed 595 cows in 20 herds for serological evidence of paratuber culosis with an ELISA procedure for which we had recently determined a sensitivity of 50% and a specificity of 98%, and we obtained an overa ll calculated real prevalence of 5,99%. In two herds with clincal case s of paratuberculosis, the calculated true prevalence of seroreactors was 21,47%. In 9 herds with clinical suspicion of Johne's disease, the rate was 4,23%, 9 herds without any clinical suspicion showed a mean prevalence of 0%. Whereas the trend was clear for groups of herds, the observed prevalence in individual herds varied from 0% to 17,9%, with out obvious association with manifest clinical problems of paratubercu losis.