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Het ministerie van EZ heeft laten onderzoeken of het paard in Nederland een rol speelt bij het ontstaan van infectieziekten die kunnen worden overgedragen van dieren op mensen (zoönosen).

In recent years, several animal disease epidemics have occurred within the European Union (EU). At the 4th Annual Meeting of the EPIZONE network (7-10 June 2010, St. Malo, France), an interactive session was run to elicit the opinions of delegates on a pre-defined list of epidemic threats to the EU. Responses from over 190 delegates, to questions relating to impact and likelihood, were used to rank six virus groups with respect to their perceived threat now (2010) and in 2020. The combined opinions of all delegates suggested that, from the pre-selected list of virus groups, foot-and-mouth disease and influenza are currently of most concern. Delegates thought that influenza would be less of a threat and zoonotic arboviruses would be more of a threat in 2020. Although the virus group rankings should not be taken as definitive, the results could be used in conjunction with experimental and field data, by scientists, policy-makers and stakeholders when assessing and managing risks associated with these virus groups.

The objective of this project was to develop a framework for risk assessment of introduction, establishment, spread and persistence of vector-borne livestock diseases by integrating the essential elements of different approaches. This framework will help risk analysts to assess the risk of vector-borne diseases, considering both likelihood of occurrence and potential impact to inform stakeholders on behalf of their decision making.

Aims: To predict the risk of incursion of Crimean-Congo haemorrhagic fever virus (CCHFV) in livestock in Europe introduced through immature Hyalomma marginatum ticks on migratory birds under current conditions and in the decade 2075–2084 under a climate-change scenario. Methods and Results: A spatial risk map of Europe comprising 14 282 grid cells (25 × 25 km) was constructed using three data sources: (i) ranges and abundances of four species of bird which migrate from sub-Saharan Africa to Europe each spring, namely Willow warbler (Phylloscopus trochilus), Northern wheatear (Oenanthe oenanthe), Tree pipit (Anthus trivialis) and Common quail (Coturnix coturnix); (ii) UK Met Office HadRM3 spring temperatures for prediction of moulting success of immature H. marginatum ticks and (iii) livestock densities. On average, the number of grid cells in Europe predicted to have at least one CCHFV incursion in livestock in spring was 1·04 per year for the decade 2005–2014 and 1·03 per year for the decade 2075–2084. In general with the assumed climate-change scenario, the risk increased in northern Europe but decreased in central and southern Europe, although there is considerable local variation in the trends. Conclusions: The absolute risk of incursion of CCHFV in livestock through ticks introduced by four abundant species of migratory bird (totalling 120 million individual birds) is very low. Climate change has opposing effects, increasing the success of the moult of the nymphal ticks into adults but decreasing the projected abundance of birds by 34% in this model. Significance and Impact of the Study: For Europe, climate change is not predicted to increase the overall risk of incursion of CCHFV in livestock through infected ticks introduced by these four migratory bird species.

Afrikaanse paardenpest (African Horse Sickness, AHS) is een vector-overdraagbare ziekte van paardachtigen, veroorzaakt door het African Horse Sickness Virus (AHSV) dat nauw verwant is aan het virus dat Blauwtong bij herkauwers veroorzaakt. De recente Blauwtong epidemie in Noordwest-Europa heeft laten zien dat lokale vectoren in staat zijn om het Blauwtongvirus (BTV) over te dragen. Het is heel goed mogelijk dat dezelfde of andere lokale vectoren in staat zullen blijken ook het Afrikaanse paardenpest virus over te dragen na een eventuele introductie in deze streken. Een uitbraak van deze ziekte in Nederland zal grote maatschappelijke gevolgen hebben gezien de plaats die het paard in de maatschappij heeft en de verwachting dat 70-90% van de besmette dieren dood zal gaan. Naar aanleiding van de mogelijkheid dat Afrikaanse paardenpest in Nederland wordt geïntroduceerd en de mogelijk ernstige gevolgen, is op verzoek van het Ministerie van Economische zaken, Landbouw en Innovatie het beleidsondersteunend project “Preventie en bestrijding van Afrikaanse paardenpest in Nederland” (BO-08-010-021) opgestart. Het project kent verschillende onderzoekslijnen waaronder een kwalitatieve risicoanalyse voor insleeproutes van Afrikaanse paardenpest in Nederland, deze risicoanalyse wordt beschreven in dit rapport.

In dit rapport worden verwachtingen uitgesproken over het toekomstig functioneren van een aantal robuuste verbindingen die geschikt worden gemaakt voor het edelhert. Ook is onderzocht hoe het gebruik zou kunnen zijn door het wilde zwijn. Er wordt ingegaan op de verwachte aantallen wilde hoefdieren in de robuuste verbindingen en hun mogelijk effect op de landbouw, de verkeersveiligheid en de diergezondheid. Jaarlijks zal naar verwachting 10-20% van de bronpopulatie naar de verbindingszones migreren. Die zogenaamde `starters¿ krijgen vervolgens te maken met de weerstand van het landschap, waardoor hun aantal afneemt, in sommige gevallen tot 0. Edelherten berokkenen per individu gemiddeld per jaar schade aan 0,03 ha landbouwgrond en wilde zwijnen aan 0,05 ha. In een willekeurig gebied kan de procentuele samenstelling van die 0,03 en 0,05 ha in gewastypen worden berekend, door de oppervlaktepercentages van de gewastypen te vermenigvuldigen met gewas- en diersoortspecifieke correctiefactoren. Jaarlijks zal ca. 3% van het aantal dieren in de verbinding sterven in het verkeer (0,2 ¿ 2 dieren/jr). Voor de beoordeling van het veterinaire risico van de robuuste verbindingen is gekeken naar: klassieke varkenspest (KVP), mond- en klauwzeer (MKZ), de ziekte van Aujeszky (ZvA), koeiengriep (IBR) en blauwtong (BT). Bij de kans op besmetting speelt een rol: het aantal dieren dat in de verbindingen wordt verwacht, de prevalentie van de ziekte onder die dieren, de bedrijfs- en dierdichtheid in en rondom de verbindingen en de mogelijkheden voor contact tussen vrijlevende en gehouden dieren. In een aantal opzichten kunnen beheerders of de sector preventieve maatregelen nemen. Als er geen wilde zwijnen toegelaten worden in de robuuste verbindingen, wordt het veterinaire risico sterk gereduceerd.

Results of serological monitoring for Salmonella in finishing pigs are used to classify herds and target control measures at herds with high prevalence. The outcome of monitoring depends on three factors: (a) the optical density percentage (OD%) used to declare a sample positive, (b) the herd classification scheme, and (c) the number of samples. The goal of this study was to analyse the impact of these three factors on the reliability and cost of Salmonella monitoring in finishing pigs. A stochastic simulation model was constructed to evaluate 12 monitoring scenarios based on: (a) four cut-off values for the OD% and (b) three herd classification schemes. Furthermore, eight different sampling schemes were evaluated. The main outputs of the model are (a) the percentage of herds changing classification as a reliability criterion and (b) the total number of samples taken as a cost criterion. Results indicated that monitoring scenarios based on cut-off OD% 10 are most reliable. Moreover, inclusion of a zero-prevalence class decreased the reliability of monitoring. The economically optimal sampling scheme depended on the monitoring scenario used.

Keywords:Classical swine fever; Cost-effectiveness; European Union; Pathway diagram; Prevention; Risk analysis; Scenario tree model; Sensitivity analysis; The Netherlands; Virus introductionThe research described in this thesis aimed to support decision-making on preventing classical swine fever virus (CSFV) introduction into disease-free regions of the European Union (EU). A risk analysis of CSFV introduction was performed. The main objective was to provide quantitative insight into the major risk factors contributing to the probability of CSFV introduction (P CSFV ). First, a pathway diagram was constructed presenting an overview of all factors that might possibly contribute to the P CSFV . Then, based on this pathway diagram, a scenario tree model was developed to calculate the annual P CSFV into member states of the EU. The main aim of this model was to analyse quantitatively those pathways that contribute most to the annual P CSFV, and the origin of these pathways. Pathways included in the model were import of pigs and pork products, returning livestock trucks, and contacts with wild boar. All (old) 15 EU member states were included as possible sources of CSFV introduction. Because the model contained many uncertain input parameters, an extensive sensitivity analysis was performed to indicate which of these parameters most influenced model results. The results indicated that only four out of 257 uncertain input parameters changed the ranking of risk factors, viz. the expected number of classical swine fever epidemics in Germany, Belgium, and the United Kingdom, and the probability that CSFV survives in an empty livestock truck travelling over a distance of 0-900 km. Model calculations based on the situation as at 2003 showed that returning livestock trucks contributed most to the annual P CSFV into the Netherlands with 50%. The most likely sources of CSFV introduction were Germany, Belgium and Spain. Finally, a cost-effectiveness analysis was performed for six measures aimed at preventing CSFV introduction into the Netherlands. Results showed that using separate livestock trucks for national and international transport was most cost-effective, especially when a worst-case scenario was assumed (i.e. for 0.95 percentile values of the annual P CSFV

Recent classical swine fever (CSF) epidemics in the European Union (EU) have clearly shown that preventing the introduction of CSF virus (CSFV) deserves high priority. Insight into all the factors contributing to the risk of CSFV introduction is a prerequisite for deciding which preventive actions are cost-effective. The relations between virus introduction and spread, prevention and control, and economic losses have been described using the conceptual framework presented in this paper. A pathway diagram provides insight into all the pathways contributing to the likelihood of CSFV introduction (LVI_CSF) into regions of the EU. A qualitative assessment based on this pathway diagram shows that regions with high pig densities generally have a higher LVI_CSF, although this cannot be attributed to pig density only. The pathway diagram was also used to qualitatively assess the reduction in LVI_CSF achieved by restructuring the pig production sector. Especially integrated chains of industrialised pig farming reduce the LVI_CSF considerably, but are also difficult and costly to implement. Quantitative assessment of the LVI_CSF on the basis of the pathway diagram is needed to support the results of the qualitative assessments described.