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Experimental infection of New Zealand merino sheep with a suspension of Mycobacterium avium subspecies paratuberculosis (Map) strain Telford: Kinetics of the immune response, histopathology and Map culture

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posted on 2023-05-03, 10:05 authored by Venkata Dukkipati, Anne Ridler, Keith Thompson, Bryce BuddleBryce Buddle, Barry Hedgespeth, Marian Price-CarterMarian Price-Carter, Douglas Begg, Richard Whittington, Brigitte Gicquel, Alan Murray
A long-term study was undertaken to monitor immune responses, faecal cultures and clinical disease in sheep experimentally infected with Mycobacterium avium subspecies paratuberculosis (Map) strain Telford. New Zealand Merino lambs (N = 56) were challenged with three oral doses of Map suspension. The lambs were weighed and faecal and blood samples obtained at different time-points. At 63 weeks post-challenge, surviving sheep were euthanised and samples of liver, ileo-caecal valve and mesenteric lymph node were collected for histopathology and Map culture. High IFN-γ and antibody responses were evident as early as 8 weeks post-C1 which persisted until the end of the trial. Approximately 92% of the sheep shed Map in faeces at 36 weeks post-challenge, with the prevalence decreasing to around 40% at the end of the trial. Thirteen sheep progressively lost weight and were euthanised between weeks 32 and 58 post-challenge. Nearly 58% of surviving sheep exhibited histo-pathological lesions in at least one of the three tissues sampled, while 42% showed acid-fast bacilli in at least one tissue. A positive Map culture in at least one tissue was obtained from approximately 85% of sheep. These results indicate that the three doses of Map challenge were highly effective in establishing Johne’s disease in NZ Merino lambs.

History

Rights statement

© 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

Elsevier

Journal title

Veterinary Microbiology

ISSN

0378-1135

Citation

Dukkipati, V. S. R., Ridler, A. L., Thompson, K. G., Buddle, B. M., Hedgespeth, B. A., Price-Carter, M., Begg, D. J., Whittington, R. J., Gicquel, B., & Murray, A. (2016). Experimental infection of New Zealand merino sheep with a suspension of Mycobacterium avium subspecies paratuberculosis (Map) strain Telford: kinetics of the immune response, histopathology and Map culture. Veterinary Microbiology, 195, 136–143. doi:10.1016/j.vetmic.2016.09.018