The results of using faecal culture as confirmation test of paratuberculosis-seropositive dairy cattle.
A total of 15,822 cattle aged 3 years and older, belonging to 378 randomly selected herds, were tested for paratuberculosis using an absorbed enzyme-linked immunosorbent assay (ELISA); 3.3% tested positive. This percentage was lowest for the group of cattle aged 3-4 years (2.3%) and highest for cattle with the age of 5-6 years (4.5%). The mean Sample to Positive (S/P) ratio of seropositive cattle vaccinated against paratuberculosis was higher (0.75 +/- 0.33) than that of seropositive, non-vaccinated cattle (0.58 +/- 0.26). Faecal samples of 422 ELISA-positive cattle were cultured for the presence of Mycobacterium avium subsp. paratuberculosis, 12% of these were contaminated. The percentage of non-contaminated samples with positive culture results was 17.3%, with a substantial difference between vaccinated (1.7%) and non-vaccinated cattle (20.2%). Of the positive cultures, the number of colonies varied from 1-10 (22% of cultures), 11-100 (22%), to more than 100 (55%). The percentage of ELISA-positive, non-vaccinated cattle tested culture-positive was positively correlated with the magnitude of the S/P ratio. This percentage varied from 12% (S/P ratio 0.3-0.5) to 58% (S/P ratio > 1.1), a result that might have implications for interpretation of the test. In this study, the percentage of ELISA-positive cattle with positive faecal culture results was limited and these individuals were mostly moderate to heavy shedders.
Muskens
J
J
Animal Health Service, P.O. Box 9, 7400 AA, Deventer, The Netherlands. j.muskens@gdvdieren.nl
Mars
M H
MH
Elbers
A R W
AR
Van Maanen
K
K
Bakker
D
D
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D002417:Cattle; D003612:Dairying; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology* / Q000302:isolation & purification; D009426:Netherlands / Q000453:epidemiology; D010283:Paratuberculosis / Q000175:diagnosis* / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D011237:Predictive Value of Tests; D014611:Vaccination / Q000662:veterinary
D000907:Antibodies, Bacterial