Mycobacterium avium subsp. paratuberculosis infection in cattle in Austria, diagnosis with culture, PCR and ELISA.
Serum samples from healthy, infected (n=11) and diseased (n=2) cattle as well as positive (n=17) and negative (n=41) reference sera were tested for antibodies to Mycobacterium avium subsp. paratuberculosis with two ELISA-methods (A-ELISA, Allied Monitors, Fayette, USA; H-ELISA, Institute of Microbiology and Animal Diseases, Veterinary University Hannover). Fecal samples of these animals were examined by PCR and culture. Also field serum samples found to be positive (n=664) or inconclusive (n=1589) by A-ELISA during a survey done on 11028 cattle of 2757 farms at different districts in Austria were retested with H-ELISA (Gasteiner et al., 1999). In both ELISA-methods total agreement between antibody detection and shedding of M. avium subsp. paratuberculosis (PCR, culture) in cases of diseased animals during the testing period was found. In subclinically infected animals H-ELISA showed a better correlation with the results of PCR and fecal culture. Reference serum samples of culturally negative cattle were negative in 98% by H-ELISA and in 82% by A-ELISA, and those of positive animals were positive in 59% by H-ELISA and in 82% by A-ELISA. The 664 A-ELISA positive field serum samples were positive in 20.5%, inconclusive in 32.5% and negative in 47% by H-ELISA. A-ELISA inconclusive sera gave positive reactions by H-ELISA in 5.2%, negative in 74.8% and inconclusive results in 20%. The highest prevalence of antibodies (7.9% by A- and 2.2% by H-ELISA) against M. avium subsp. paratuberculosis were found in cattle at the age of six and seven years. Seropositive animals were found at all tested ages. The A-ELISA gave two to three times more positive reactors than the H-ELISA. Also both tests showed the highest prevalence of reagents among Holstein Friesian (6.2% by A-ELISA, 2.5% by H-ELISA) followed by other cattle breeds. Seropositive cattle were observed in all districts of Austria in 3. 3-7.1% and in 0.5-1.8% of herds according to A- and H-ELISA, respectively.
Gasteiner
J
J
IInd Medical Clinic for Ruminants and Swine, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria. walter.baumgartner@vu-wien.ac.at
Awad-Masalmeh
M
M
Baumgartner
W
W
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001317:Austria / Q000453:epidemiology; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000453:epidemiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D010283:Paratuberculosis / Q000175:diagnosis* / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial