Monte Carlo simulation of virus introduction into the Netherlands

In order to improve the understanding of the risk of introducing classical swine fever (CSF) and foot-and-mouth disease (FMD) into the Netherlands, a Monte Carlo simulation model was developed. The model, VIRiS (Virus Introdu ction Risk Simulation model) describes virus introduction into the Netherla nds from outbreaks in other European countries. VIRiS is aimed at supportin g decision makers involved in disease prevention. The model is based on his torical and experimental data, supplemented with expert judgement, and prov ides the expected number, location and cause of primary outbreaks in the Ne therlands. The paper gives a detailed description of the design and behavio ur of VIRiS. The default outcomes of VIRiS show that in the current situati on, the western and northern regions of the Netherlands are most prone to o utbreaks of CSF and FMD. Most outbreaks originate from the countries neighb ouring the Netherlands and the countries of southern Europe. Several altern ative prevention strategies were evaluated using a combination of the VIRiS model and models describing the spread and economic consequences of outbre aks. A considerable financial window is available for measures aimed at spe eding up the detection of epidemics in countries from which a Dutch outbrea k may originate. Complete elimination of the risk associated with the risk factor 'returning trucks' reduces the annual losses due to FMD and CSF epid emics by approximate to US$ 9 million. The approach is general and could al so be applied to other diseases and countries. (C) 1999 Elsevier Science B. V. All rights reserved.