Abstract
African swine fever (ASF) is a severe hemorrhagic disease that affects domestic and wild suids. Since its introduction nine years ago in the European Union, the wild boar population is one of the main drivers of the disease's local spread and its maintenance there. Spain is currently free of ASF, although the risk of introduction is non-negligible. Due to the worldwide distribution of the disease, contaminated pork products with ASF virus (ASFV) pose a major threat to ASF-free regions. Thus, the aim of the study was to identify areas in mainland Spain with a higher risk of indirect exposure of wild boar to ASFV-contaminated pork products illegally introduced via seaports in the event that the scenario ever occurs.
First, the Spanish seaports that receive traffic from ASF-affected countries were detected. A risk score was assigned to each seaport based on several parameters, related to the intensity of connections between each at-risk seaport and the origin countries, the number of connections, as well as the level of ASF affectation of the origin countries. Places where the indirect exposure of wild boar to potential ASFV-contaminated products was identified: gas stations, rest areas, and near roads in protected natural spaces. Then, we used a weighted linear combination analysis accounting for the Kernel density of the inverse distance of gas stations, rest areas, and protected natural spaces to seaports, as well as the first two contact areas to the suitability of wild boars.
Our findings highlighted relatively small at-risk areas where wild boar exposure to ASFV-contaminated products could occur. Two seaports, namely Barcelona and Valencia, presented a higher relative risk of wild boar exposure and higher risk score. This early warning system tool can aid with the implementation of cost-effective active surveillance and preventive measures in the framework of the Spanish wildlife health surveillance program for ASF.