Epidemiological risk factors of Aujeszky's disease in wild boars (Sus scrofa) and domestic pigs in Spain

An Aujeszky's disease (AD) control and eradication campaign started in Spain in 1995, and as a result, AD virus (ADV) seroprevalences have notably diminished in Spanish domestic pig herds, but eradication has not yet been achieved. Since the presence of ADV in Spanish wild boar populations can impede schemes to eradicate ADV in domestic pig, we conducted analyses of risk factors and investigated associations between the patterns of ADV seroprevalence at the municipal level in the wild boar and the domestic pig, respectively, in south-central Spain. There was a clear influence of individual factors on the risk of wild boar to test positive to ADV. Concerning the domestic pig, higher ADV seroprevalences were observed with increasing numbers of pigs per farm. Indoor pig farms showed higher seroprevalences than open-air farms. Our results show that, at least at the study scale, the level of ADV seroprevalence in domestic pig farms is not influenced by the level of ADV seroprevalence in the coexisting wild boar populations. Also, there was no influence of domestic pigs ADV seroprevalence on the risk of wild boars to test seropositive. Finally, there was no evidence for a statistical association between ADV seroprevalence levels in wild boar and domestic pig at the municipal level in the study region. These findings are of interest for both veterinary and public health authorities. Nevertheless, more effort is needed in order to elucidate the nature of particular ADV outbreaks in domestic pigs in the study region due to possible contacts with wild boars, which will probably require a molecular approach.