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  • Author or Editor: Beverly A. Byrum x
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Objective—To estimate the prevalence of Mycobacterium avium subsp paratuberculosis infection among cows on beef operations in the United States.

Design—Cross-sectional seroprevalence study.

Sample Population—A convenience sample of 380 herds in 21 states.

Procedure—Serum samples were obtained from 10,371 cows and tested for antibodies to M avium subsp paratuberculosis with a commercial ELISA . Producers were interviewed to collect data on herd management practices.

Results—30 (7.9%) herds had 1 or more animals for which results of the ELISA were positive; 40 (0.4%) of the individual cow samples yielded positive results. None of the herd management practices studied were found to be associated with whether any animals in the herd would be positive for antibodies to M avium subsp paratuberculosis.

Conclusions and Clinical Relevance—Results suggest that the prevalence of antibodies to M avium subsp paratuberculosis among beef cows in the United States is low. Herds with seropositive animals were widely distributed geographically. (J Am Vet Med Assoc 2001;219:497–501)

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in Journal of the American Veterinary Medical Association


Objective—To evaluate sensitivity and specificity of a new ELISA for antibodies against Mycobacterium avium subsp paratuberculosis.

Design—Cross-sectional observational survey.

Sample Population—Serum samples from 590 cattle that were infected with M avium subsp paratuberculosis and 723 cattle that were not infected.

Procedure—Serum samples were tested by use of an ELISA for antibodies against M avium subsp paratuberculosis.

Results—Sensitivity of the test varied from 15.4 to 88.1%, depending on the clinical stage and bacterial shedding status of the cattle.

Conclusions and Clinical Relevance—Results obtained with use of the new ELISA agreed favorably with those of a previous ELISA. Practitioners must be aware of variability in the sensitivity of the test, which depends on the clinical and shedding status of the cattle, because this may affect interpretation of test results. (J Am Vet Med Assoc 2001;218:1163–1166)

Full access
in Journal of the American Veterinary Medical Association