The proportion of CPs estimated to have been infected is 2% (1.5%, 2.5%), equating to 62 farms (Figure 6b ). Over the whole epidemic, we estimated 1.5% (0.8%, 2.1%) of farms designated as DCs were infected (19 farms). This estimate (Figure 6c ) does not allow for higher risk of infection implied by the veterinary judgement that led to those DCs being identified, which may mean that a higher proportion were in fact infected. If we assume that DCs were 3 times more likely to be infected due to their status than the model would predict, then the incidence of infection in DCs goes up accordingly, i.e. to 4.6% or 59 farms.