Evaluation of enzyme-linked immunosorbent assays performed on milk and serum samples for detection of paratuberculosis in lactating dairy cows.
OBJECTIVE
To determine whether results obtained for milk and serum samples with ELISAs intended for diagnosis of paratuberculosis in dairy cows were comparable to results obtained by means of mycobacterial culture of fecal samples.


METHODS
Cross-sectional study.


METHODS
689 lactating dairy cows in 9 Ontario herds.


METHODS
Milk, serum, and fecal samples were obtained from all cows. Fecal samples were submitted for mycobacterial culture. Serum samples were tested with a commercially available ELISA for antibodies against Mycobacterium paratuberculosis, and preserved milk samples were tested with an indirect ELISA for antibodies against M paratuberculosis.


RESULTS
Results were positive for 130 of the 689 (18.9%) serum samples, 77 of the 689 (11.1%) milk samples, and 72 of the 689 (10.4%) fecal samples. The level of agreement between results for milk and serum samples was only moderate. Proportions of positive results for serum and fecal samples were significantly different, but proportions of positive results for milk and fecal samples were not significantly different. In addition, results for milk samples had a higher level of agreement with results of mycobacterial culture than did results for serum samples.


CONCLUSIONS
Results suggest that the indirect ELISA used on milk samples may be a convenient method of detecting paratuberculosis in dairy herds.
Hendrick
Steven H
SH
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
Duffield
Todd E
TE
Kelton
David E
DE
Leslie
Ken E
KE
Lissemore
Kerry D
KD
Archambault
Marie
M
D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis* / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000276:immunology; D015169:Colony Count, Microbial / Q000662:veterinary; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D008892:Milk / Q000382:microbiology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology* / Q000302:isolation & purification; D010283:Paratuberculosis / Q000175:diagnosis* / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial