Control of paratuberculosis in five cattle farms by serological tests and faecal culture during the period 1990-1999

In the Slovak Republic, clinical paratuberculosis was detected for the firs t time in two cows in the farm NT in 1989. Gradually the disease spread to another four farms: M, HJ, H, and C, where there were 1 490 cows, 1 100 cal ves and 1 300 heifers. The introduction of Mycobacterium avium subspecies p aratuberculosis to these farms was most probably due to the importation of 60 Holstein heifers from Denmark to farm NT in the late 1970s. In the mid-1 980s, because of common housing with apparently healthy heifers, the remain ing four free herds also became infected with paratuberculosis. In 1990, an eradication programme against paratuberculosis was established. In the fir st stage (during 1990-1992) of the programme all animals older than 18 mont hs were examined by three serological tests: AGID (agar-gel-immunodiffusion ), CFT (complement fixation test) and ELISA. Animals with repeatedly positi ve serological results were culled from the herd including clinically suspe ct animals. In the second stage (from 1992) serological tests were suppleme nted by two parallel faecal cultures per year. In 1990, the incidence of cl inical paratuberculosis among the five farms varied (M - 4.1%, HJ 1.5%, H - 0%, C - 0% and NT - 0.5%). Cases of infection (n = 528) were divided into three groups: Ist without clinical signs and few CFU in faeces and/or gastr ointestinal tract (60.8%); IIrd without clinical signs, and numerous CFU in faeces and/or gastrointestinal tract (20.1%); IIIrd clinically affected an d numerous CFU in faeces and gastrointestinal tract (19.1%). Thus, faecal s urveillance enabled us to cull individuals that were in the preclinical sta ge of the disease. The incidence of the disease as of 1999 on farm M was 0% and on farms HJ, H and C was only 2.0%. However, on farm NT the prevalence was still high (e.g. 25.8% in 1998) which may be due to the common housing of new-born calves and cows for two months between 1993-1996.