**4.2 Prevalence rates**

Overall prevalence rates reported for bTB in wild boar, red deer and fallow deer in Iberian Peninsula are among the highest recorded for these species worldwide (Corner, 2006; Nishi *et al*.; 2006, Wilson *et al*., 2008). Interestingly, prevalence rates in wild boar are invariably higher than in sympatric red or fallow deer (Gortázar *et al*., in press).

Most studies report no sex differences in infection rates, but Santos *et al*. (2009) reported a significantly higher infection rate in female wild boar, presumably linked to more frequent social behaviour of females compared to males. Several studies report age differences in infection rates in wild boar, but data is conflicting since some authors reported increasing prevalence rates with age (e.g. Vicente *et al*., 2006a,b), while others found higher prevalence rate in juveniles (e.g. Gortázar *et al*., 2008; Santos *et al*., 2009). Age and sex differences in prevalence rates were also reported in red deer (Vicente *et al*., 2006a), which were higher for males and increased with age. This gender difference was already reported for cervids in North America (O'Brien *et al*., 2006).
