Seroprevalence of Johne's-disease infection in dairy cattle in California, USA

John M Adaska, Randall J. Anderson

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


A total of 1950 serum samples from dairy cattle in California, USA were tested for the presence of antibodies to Mycobacterium avium subspecies paratuberculosis (MAP) using a commercial enzyme-linked immunosorbent assay (ELISA) kit. The sampled animals came from 65 herds and were sampled to reflect the relative numbers and distribution of dairy herds within three geographic regions in the state. Using the manufacturers suggested cut-off for a positive test, 89 animals (4.6%) were positive. The seroprevalence was 6.9% in the northern region of the state, 3.7% in the central region and 5.2% in the southern region. Using the sensitivity and specificity claimed by the manufacturer of the ELISA kit, the true prevalence in California dairy cattle overall was calculated as 9.4% (99% CI, 7.7%, 11.1%) and the true prevalences for the northern, central and southern regions were 14.1% (99% CI, 9.6%, 18.65%), 7.5% (99% CI, 5.6%, 9.4%), and 10.6% (99% CI, 5.9%, 15.6%), respectively.

Original languageEnglish (US)
Pages (from-to)255-261
Number of pages7
JournalPreventive Veterinary Medicine
Issue number3
StatePublished - Aug 28 2003


  • Bovine
  • California
  • Johne's disease
  • Prevalence

ASJC Scopus subject areas

  • Animal Science and Zoology
  • veterinary(all)


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