Prevalence of paratuberculosis in organized and unorganized dairy cattle herds in West Bengal, India.

Aim: The aim of this study was to determine the prevalence pattern of Mycobacterium avium subsp. paratuberculosis, the causative agent of paratuberculosis or Johne's disease, in unorganized as well as organized cattle herds in West Bengal. Materials and Methods: Four organized cattle farms with identical management practice in Nadia (n=3) and South 24 Parganas (n=1) districts and three unorganized cattle herds, one each from three districts, namely, Burdwan, North 24 Parganas, and Purba Midnapur, were selected randomly and screened for paratuberculosis by delayed-type hypersensitivity (DTH) and enzyme-linked immunosorbent assay (ELISA). Results: Of 191 animals tested by DTH, 57 (29.8%) were found to be positive in comparison to 72 (37.7%) by ELISA. In organized farms, seropositivity varied from 13.3% to 53.1%, whereas in unorganized sector, it ranged from 5% to 6.7% with one area having exceptionally high prevalence, i.e. 53.3%. The range of positivity detected by DTH both in organized farms and backyard sectors varied from 0% to 46.7%. By employing both DTH and ELISA together, the positivity of animals in organized and unorganized herds was 19.9% and 8%, respectively. Conclusion: The results indicate that animals in organized farms are much more prone to paratuberculosis than others. For screening the herd, both DTH and ELISA should be used simultaneously to increase the test sensitivity in order to minimize its further spread adopting control programs. [ABSTRACT FROM AUTHOR]