**3.4 Determinant factors of disease**

280 Epidemiology Insights

Fig. 1. Map displaying reported prevalence rates for bTB in the wild boar by administrative divisions of Iberian Peninsula (provinces in Spain, districts in Portugal). Bacteriological culture data (Aranaz *et al*., 2004; de Mendoza *et al*., 2006; Vicente *et al*., 2006a; Gortázar *et al*., 2008; Santos *et al*., 2009; Pinto *et al*., 2011) and serology data (Boadella *et al*., 2011; Santos *et al*., unpublished data) combined. The highest recorded prevalence for each administrative

Again, few published articles address or allow addressing the geographical trend in bTB prevalence rates. In South-central Spain, an area roughly corresponding to Sierra Morena and Montes de Toledo was shown to have high prevalence rates, which declined towards the periphery of the area (Vicente *et al*., 2006a). In Doñana, wild boar and red deer show an increasing South-North gradient in prevalence rates (Gortázar *et al*., 2008). In Portugal, bTB was not detected in western regions, while present in the eastern portion of the country (Santos *et al*., 2009). Also in Eastern-central Portugal, wild boar and red deer populations show an increasing North-South gradient in prevalence rates (Pinto *et al*., 2011). In Southcentral Spain, lack of geographical autocorrelation in prevalence rates was reported (Vicente

division is shown.

*et al*., 2006b).

Several risk and protective factors for bTB in both wild boar and red deer have been identified (Table 4). Most of the identified risk factors relate to host and other sympatric host's population factors, but also to environmental, management and historical factors. On the other hand, protective factors are mainly associated with environmental variables (Table 4). Notably, only one study has identified fencing, feeding and watering of wild ungulate populations as risk factors.


Table 4. Determinant factors of bTB occurrence identified in wild boar and red deer epidemiological studies in the Iberian Peninsula.
