Investigations into Resistance and Susceptibility to Johne’s Disease in

ii Johne’s disease (JD), caused by the pathogen Mycobacterium avium subspecies paratuberculosis (MAP), is a chronic inflammatory bowel disease of ruminants that is characterised in its clinical stage by progressive weight loss/wasting and profuse diarrhea. Immune responses to MAP infection are initially characterised by a Th1 T cell response that subsequently decreases over disease progression. Detection of MAP occurs via pathogen recognition receptors (PRR) including NOD2 and the toll like receptors (TLR). Mutations in NOD2 have been identified as a susceptibility factor to JD. To cause infection MAP has a documented role in manipulating its environment including gene expression profiles. The aims of this project was to map the NOD2 gene for mutations associated with resistance or susceptibility to JD in red deer (Cervus elaphus), and to investigate the gene expression profiles of deer of demonstrated resistance and susceptibility for informative factors in disease progression. Foundational work, carried out at AgResearch Invermay investigating the heritabilit