Proceedings of the 10th International Colloquium on Paratuberculosis

#193 Development <strong>of</strong> an experimental infection model for Johne’s disease using a lyophilised
pure culture <strong>of</strong> Mycobacterium avium subspecies paratuberculosis
Douglas Begg, Kumudika de Silva, Lyrissa Di Fiore, Deborah Talyor, Katrina Bower, Ling Zhong,
Satoko Kawaji, David Emery, Richard Whittington
University <strong>of</strong> Sydney, Australia
In <strong>the</strong> first study <strong>of</strong> its type, a standardised experimental model for Johne’s disease was developed utilising a
low passage pure culture seed stock <strong>of</strong> Mycobacterium avium subspecies paratuberculosis (M.ptb). Repeatable
infections <strong>of</strong> known duration are required for comparison and validation <strong>of</strong> new diagnostic tests and vaccines.
Experimental inoculations <strong>of</strong> sheep resulted in repeatable infection rates across multiple trials, modulated
by <strong>the</strong> interval between inoculation and examination. The clinical disease outcome from <strong>the</strong> pure laboratory
culture was manifested later than that obtained using a gut homogenate from a naturally affected sheep but
o<strong>the</strong>r measures <strong>of</strong> infection were similar. Immunological diagnostic assays showed most <strong>of</strong> <strong>the</strong> animals were
IFN-g positive in <strong>the</strong> early stages <strong>of</strong> <strong>the</strong> infection. An increasing number <strong>of</strong> sheep became M.ptb-specific antibody
positive over time and shed M.ptb in <strong>the</strong>ir faeces. The consistency <strong>of</strong> this experimental infection model
will enable study <strong>of</strong> pathological, bacteriological and immunological responses for pathogenetic analyses, diagnostic
test comparisons as well as assessment <strong>of</strong> vaccine efficacy.
#194 Expression pr<strong>of</strong>ile <strong>of</strong> certain cytokine genes in tissues <strong>of</strong> two distinct classes
(paucibacillary and multibacillary) <strong>of</strong> ovine paratuberculosis
Ganesh G Sonawane, Bhupendra N. Tripathi, Shirish D Narnaware
Central Sheep and Wool Research Institute, Awikanagar, India; Indian Veterinary Research Institute, Izatnagar, India
Expression <strong>of</strong> certain cytokines was quantified in tissues <strong>of</strong> paucibacillary (PB), multibacillary (MB) and uninfected
control sheep by quantitative real-time-polymerase chain reaction (qRT-PCR) and analysed. In <strong>the</strong>
small intestine, PB sheep showed significant enhancements in <strong>the</strong> expression <strong>of</strong> IL-10 (4 folds), TGF-b (4.7
folds), iNOS (3.8 folds), IFN-g (4 folds) and TRAF-1 (3.5 folds, non-significant) in comparison to similar tissues
from uninfected control sheep. IL-1a (2.7 folds) expression was, however, significantly reduced (P