Risk assessments are often developed to assess the risk for a single disease and introduction pathway. However in recent years, generic risk tools have been developed that can assess the risk of incursion for multiple pathogens via multiple pathways. A collaborative project provided an opportunity for cross validation of several generic risk tools; each assessing an identical incursion scenario using, where possible, the same input data.
Materials & Methods
Seven generic RA tools were used to assess the incursion risk of African swine fever (ASF) virus to the Netherlands and Finland for the epidemiological situation in 2017 and for two hypothetical scenarios in which ASF cases were reported in wild boar and/or domestic pigs in Germany. The generic tools ranged from qualitative risk assessment tools to stochastic spatial risk models but were all parameterised using the same global databases for disease occurrence and trade in live animals and animal products. The risks for each country and scenario were calculated for each tool, for the three pathways most in common (trade in live animals, trade in animal products, and wild boar movements); relative risks were computed, and then compared across tools.
For the 2017 situation, all tools evaluated the risk to the Netherlands to be higher than Finland for the live animal trade pathway, the risk to Finland the same or higher as the Netherlands for the wild boar pathway, while the tools were inconclusive on the animal products pathway. All tools agreed that the hypothetical presence of ASF in Germany increased the risk to the Netherlands, but not to Finland.
The case study illustrated that conclusions on the risk of ASF virus incursion were similar across the generic RA tools, despite differences observed in calculated risks. It was concluded that the cross-validation contributed to the credibility of the results.