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Leverbotlijkt steeds vaker een knelpunt tezijn. Veehouders hebben behoefte aankennis over preventieve maatregelen,alternatieve bestrijdingsmogelijkheden enhet vermijden van resistentieontwikkeling.Binnen het project ‘Integrale diergezondheid:beheersing van leverbot’,is een instrument ontwikkeld omde leverbotstatus op het bedrijf tebeoordelen, de risicofactoren in kaartte brengen en mogelijke preventievemaatregelen aan te geven.

Leverbotinfecties zijn in toenemende mate een knelpunt bij melkgevende koeien die weiden of vers gras op stal gevoerd krijgen. Leverbotinfecties brengen verliezen met zich mee die onderschat worden, zoals verminderde groei van jongvee, verminderde weerstand, verminderde melkproductie en afkeuring van levers van geslachte dieren.

Pseudocercospora fijiensis causes black Sigatoka disease of banana. It is one of the most damaging threats of the crop requiring excessive fungicide applications for disease control as the major export “Cavendish” clones are highly susceptible. The consequence of this practice is the reduced efficacy of disease management strategies due to increasing levels of fungicide resistance. In this thesis the history and current practices of black Sigatoka disease management as well as the underlying mechanisms of fungicide resistance to a major group of fungicides are described. We discovered that both target site mutations and promotor insertions are crucial for modulating sensitivity. The more insertions, the higher the expression of the gene and the more resistant the strain. Using this information, we advocate modern monitoring techniques and improved disease control strategies as well as the urgent need for innovative banana breeding to develop resistant varieties for a sustainable global banana production.

INTRODUCTION Diabetes is a worldwide epidemic, causing a high disease and economic burden. Type 2 diabetes, the most common form of diabetes, is associated with overweight and obesity and an unfavourable lifestyle, including unhealthy diet and physical inactivity. Over the last two decades, many large-scale experimental trials have shown that type 2 diabetes can be delayed or prevented by lifestyle modification in high-risk subjects. This evidence has been translated and implemented in interventions in real-world settings, however, no (cost)effective diabetes prevention programme in Dutch primary health care was available at the start of the current project in 2008. Therefore the SLIMMER study (SLIM iMplementation Experience Region Noord- en Oost-Gelderland) was started in which the SLIM intervention, revealing a 47% diabetes risk reduction, was translated to Dutch primary health care. The aim of this thesis was to implement the SLIMMER intervention in Dutch primary health care and to evaluate its (cost)effectiveness and implementation. METHODS In 2010-2011, the SLIMMER intervention was tested for its feasibility and desired impact in a one-year pilot study (n = 31) with process evaluation, including quantitative and qualitative methods. From 2011 to 2014, the SLIMMER intervention was implemented on a larger scale in Dutch public health and primary health care. A randomised controlled trial was conducted (n = 316), including subjects aged 40 to 70 years with impaired fasting glucose or high risk of diabetes. The 10-month SLIMMER intervention involved a dietary and physical activity programme, including case management and a maintenance programme. The control group received usual health care. A logic model of change was composed to link intervention activities with intervention outcomes in a logical order. Primary outcome was fasting insulin. Measurements were performed at baseline and after 12 and 18 months and covered quality of life, clinical and metabolic risk factors (e.g. glucose tolerance, serum lipids, body fatness, and blood pressure), and eating and physical activity behaviour. Furthermore, a process evaluation including quantitative and qualitative methods was conducted. Data on process indicators (recruitment, reach, dose received, acceptability, implementation integrity, and applicability) were collected in semi-structured interviews with health care professional (n = 45) and intervention participant questionnaires (n = 155). Moreover, cost-effectiveness analyses were performed from both a societal and a health care perspective. Participants completed questionnaires to assess health care utilisation, participant out-of-pocket costs, and productivity losses. RESULTS The pilot study showed that participants lost on average 3.5 kg (p = 0.005) of their body weight. Both participants and health care professionals were satisfied with the intervention, which was implemented as planned and appeared to be suitable for application in practice. Refinements were identified and made prior to further implementation. The randomised controlled trial showed that after 12 and 18 months, the intervention group significantly improved weight (β=-2.7 kg (95% CI: -3.7;-1.7) and β=-2.5 kg (95% CI: -3.6;-1.4), respectively), and fasting insulin (β=-12.1 pmol/l (95% CI: -19.6;-4.6) and β=-8.0 pmol/l (95% CI: -14.7;-0.53), respectively) compared with the control group. Intervention subjects improved weight and glucose tolerance, independent of manner of recruitment (laboratory glucose test or Diabetes Risk Test). Furthermore, intake of total and saturated fat decreased and fibre intake increased in the intervention group compared with the control group, both at 12 and 18 months (p < 0.05). The DHD-index score – indicating adherence to the Dutch dietary guidelines – was significantly higher in the intervention group than in the control group, both at 12 and at 18 months (p < 0.05). Vigorous activities and physical fitness improved both at 12 and at 18 months. Finally, beneficial changes in several domains of quality of life were found both at 12 and at 18 months, although not all domains reached statistical significance. From the process evaluation it was revealed that it was possible to recruit the intended high-risk population, and the SLIMMER intervention was very well received by both participants and health care professionals. The intervention programme was to a large extent implemented as planned and was applicable in Dutch primary health care. Higher dose received and participant acceptability were related to improved health outcomes and dietary behaviour, but not to physical activity behaviour. The cost-effectiveness analysis showed that, from a societal perspective, the incremental costs of the SLIMMER lifestyle intervention were €547 and that the incremental effect was 0.02 QALY, resulting in an incremental cost-effectiveness ratio (ICER) of 28,094/QALY. When cost-effectiveness was calculated from a health care perspective, the ICER decreased to 13,605/QALY, with a moderate probability of being cost-effective (56% at a willingness to pay (WTP) of €20,000/QALY and 81% at a WTP of €80,000/QALY. CONCLUSION In conclusion, this study showed that a thorough preparation of translation and implementation has led to a cost-effective intervention to prevent type 2 diabetes which is feasible to implement in Dutch primary health care. In fact, our clinical effects were larger than those in most other real-world intervention programmes, and most effects sustained at 18 months. Furthermore, we showed that a higher intervention dose and participant acceptability were associated with improved health outcomes and dietary behaviour. Further research is needed on effects and costs over longer follow-up, effective intervention components, and consequences of suggested adaptations of the programme on intervention effectiveness. The results of this study provide valuable insights that can contribute to structural embedding and funding of effective diabetes prevention programmes in Dutch primary health care.

INTRODUCTION Diabetes is a worldwide epidemic, causing a high disease and economic burden. Type 2 diabetes, the most common form of diabetes, is associated with overweight and obesity and an unfavourable lifestyle, including unhealthy diet and physical inactivity. Over the last two decades, many large-scale experimental trials have shown that type 2 diabetes can be delayed or prevented by lifestyle modification in high-risk subjects. This evidence has been translated and implemented in interventions in real-world settings, however, no (cost)effective diabetes prevention programme in Dutch primary health care was available at the start of the current project in 2008. Therefore the SLIMMER study (SLIM iMplementation Experience Region Noord- en Oost-Gelderland) was started in which the SLIM intervention, revealing a 47% diabetes risk reduction, was translated to Dutch primary health care. The aim of this thesis was to implement the SLIMMER intervention in Dutch primary health care and to evaluate its (cost)effectiveness and implementation. METHODS In 2010-2011, the SLIMMER intervention was tested for its feasibility and desired impact in a one-year pilot study (n = 31) with process evaluation, including quantitative and qualitative methods. From 2011 to 2014, the SLIMMER intervention was implemented on a larger scale in Dutch public health and primary health care. A randomised controlled trial was conducted (n = 316), including subjects aged 40 to 70 years with impaired fasting glucose or high risk of diabetes. The 10-month SLIMMER intervention involved a dietary and physical activity programme, including case management and a maintenance programme. The control group received usual health care. A logic model of change was composed to link intervention activities with intervention outcomes in a logical order. Primary outcome was fasting insulin. Measurements were performed at baseline and after 12 and 18 months and covered quality of life, clinical and metabolic risk factors (e.g. glucose tolerance, serum lipids, body fatness, and blood pressure), and eating and physical activity behaviour. Furthermore, a process evaluation including quantitative and qualitative methods was conducted. Data on process indicators (recruitment, reach, dose received, acceptability, implementation integrity, and applicability) were collected in semi-structured interviews with health care professional (n = 45) and intervention participant questionnaires (n = 155). Moreover, cost-effectiveness analyses were performed from both a societal and a health care perspective. Participants completed questionnaires to assess health care utilisation, participant out-of-pocket costs, and productivity losses. RESULTS The pilot study showed that participants lost on average 3.5 kg (p = 0.005) of their body weight. Both participants and health care professionals were satisfied with the intervention, which was implemented as planned and appeared to be suitable for application in practice. Refinements were identified and made prior to further implementation. The randomised controlled trial showed that after 12 and 18 months, the intervention group significantly improved weight (β=-2.7 kg (95% CI: -3.7;-1.7) and β=-2.5 kg (95% CI: -3.6;-1.4), respectively), and fasting insulin (β=-12.1 pmol/l (95% CI: -19.6;-4.6) and β=-8.0 pmol/l (95% CI: -14.7;-0.53), respectively) compared with the control group. Intervention subjects improved weight and glucose tolerance, independent of manner of recruitment (laboratory glucose test or Diabetes Risk Test). Furthermore, intake of total and saturated fat decreased and fibre intake increased in the intervention group compared with the control group, both at 12 and 18 months (p < 0.05). The DHD-index score – indicating adherence to the Dutch dietary guidelines – was significantly higher in the intervention group than in the control group, both at 12 and at 18 months (p < 0.05). Vigorous activities and physical fitness improved both at 12 and at 18 months. Finally, beneficial changes in several domains of quality of life were found both at 12 and at 18 months, although not all domains reached statistical significance. From the process evaluation it was revealed that it was possible to recruit the intended high-risk population, and the SLIMMER intervention was very well received by both participants and health care professionals. The intervention programme was to a large extent implemented as planned and was applicable in Dutch primary health care. Higher dose received and participant acceptability were related to improved health outcomes and dietary behaviour, but not to physical activity behaviour. The cost-effectiveness analysis showed that, from a societal perspective, the incremental costs of the SLIMMER lifestyle intervention were €547 and that the incremental effect was 0.02 QALY, resulting in an incremental cost-effectiveness ratio (ICER) of 28,094/QALY. When cost-effectiveness was calculated from a health care perspective, the ICER decreased to 13,605/QALY, with a moderate probability of being cost-effective (56% at a willingness to pay (WTP) of €20,000/QALY and 81% at a WTP of €80,000/QALY. CONCLUSION In conclusion, this study showed that a thorough preparation of translation and implementation has led to a cost-effective intervention to prevent type 2 diabetes which is feasible to implement in Dutch primary health care. In fact, our clinical effects were larger than those in most other real-world intervention programmes, and most effects sustained at 18 months. Furthermore, we showed that a higher intervention dose and participant acceptability were associated with improved health outcomes and dietary behaviour. Further research is needed on effects and costs over longer follow-up, effective intervention components, and consequences of suggested adaptations of the programme on intervention effectiveness. The results of this study provide valuable insights that can contribute to structural embedding and funding of effective diabetes prevention programmes in Dutch primary health care.

Terwijl in Nederland de discussie over de aanpak van schimmelziektes in buxus soms hevig oplaait, heeft België inmiddels door middel van veredeling duurzame buxussoorten ontwikkeld die beter bestand zijn tegen de schimmels.

Een zoönose is een infectieziekte die overgedragen kan worden van gewervelde dieren naar mensen of omgekeerd. Ruim 60 procent van de ziekteverwekkers bij mensen heeft een zoönotisch karakter. Het verkleinen van het risico van zoönosen voor de mens is één van de taken van het CVI. Samen met diverse partners richt het CVI zich op het vroegtijdig opsporen van deze ziekteverwekkers in het dierlijk reservoir en op het ontwikkelen van bestrijdingsmethoden. Het CVI is referentiecentrum voor aangifteplichtige dierziekten inclusief zoönosen en voert onderzoeksprojecten uit op het gebied van dierziektebestrijding voor zowel de overheid als in opdracht van externe partijen en in (inter)nationale samenwerkingsverbanden. Onderzoek aan zoönosen is daar een belangrijk onderdeel van. Ten behoeve van een betere preventie, opsporing en bestrijding van zoönosen wil het CVI het onderzoek naar opkomende zoönosen versterken. Een aantal voorbeelden van zoönosen waar het CVI aan werkt, wordt kort besproken.

Leverbotlijkt steeds vaker een knelpunt tezijn. Veehouders hebben behoefte aankennis over preventieve maatregelen,alternatieve bestrijdingsmogelijkheden enhet vermijden van resistentieontwikkeling.Binnen het project ‘Integrale diergezondheid:beheersing van leverbot’,is een instrument ontwikkeld omde leverbotstatus op het bedrijf tebeoordelen, de risicofactoren in kaartte brengen en mogelijke preventievemaatregelen aan te geven.

Het is inmiddels een bekend feit dat ontwormingsmiddelen die aan vee worden gegeven, giftig kunnen zijn voor de mestfauna, de insecten die zich met mest voeden en er hun eieren in leggen. Het verdwijnen van bepaalde soorten mestfauna kan er in bepaalde gevallen toe leiden dat de afbraak van mest in het veld vertraagd wordt, zo blijkt uit buitenlandse studies. Enquêtes wezen eerder uit dat ontwormingsmiddelen in veel Nederlandse natuurgebieden worden toegediend aan grote grazers. Komen dit soort ecologische effecten dus ook in onze natuurgebieden voor? Dit is de afgelopen jaren door Alterra onderzocht in opdracht van het ministerie van EL&I.

Licht zou wel eens een belangrijke factor kunnen zijn die ervoor zorgt of planten nu wel of niet gevoelig zijn voor schimmelaantastingen. Dat is een hele nieuwe invalshoek, want tot op heden werd alleen een relatie met het kasklimaat aangetoond. Te droog, te nat, te warm of de koud. Zelfs bij een hoge RV hoeft een plant niet ziek te worden, stellen Jantineke Hofland-Zijlsta en Luc Stevens. Zij doen fundamenteel onderzoek naar plantweerbaarheid in relatie tot licht.

Samenvatting van de inaugurele rede van Francine Govers op 11 juni 2009. Dit artikel beschrijft de stand van zaken in het onderzoek aan oömyceten en in het bijzonder aan Phytophthora infestans, de veroorzaker van de aardappelziekte. Er wordt ingegaan op ziektebestrijding en resistentieveredeling, de diversiteit van Phytophthora en zijn gastheren en de genetische blauwdruk: het DNA, de genen, de effectoren en de resistentiegenen.

Scrapie is a fatal infectious neurodegenerative disease for which susceptibility is associated with polymorphisms in the ovine prion protein (PrP) gene. Scrapie-eradication programmes are based on eliminating the susceptible VRQ allele and/or breeding for the resistant ARR allele. In rare breeds or breeds with a low frequency of the ARR allele this can lead to unacceptably high inbreeding rates with associated increased risk of genetic defects and inbreeding depression. The conservation status of populations with inbreeding rates (DeltaF) above 1% is considered critical. In the Dutch rare sheep breed the Mergellander animals carrying ARR alleles are closely related to one another, and could reach 1.53% when only ARR/ARR animals are used as parents. Inbreeding rates can be reduced by selecting the set of parents according to their average co-ancestry. We minimised inbreeding rates by calculating the optimal contribution of each ram and selection of ewes. This resulted in inbreeding rates of -0.17% with exclusive use of homozygous ARR rams, and -0.38% if use of heterozygous rams was allowed as well. Thus sophisticated breeding programs can prevent unacceptably high inbreeding rates when breeding for scrapie resistance.

Een groot deel van de kastanjebomen in ons land bloedt. De oorzaak is een lastig te bestrijden bacterie. Wageningse wetenschappers hebben nu een oplossing die even simpel als geniaal is: verwarmen.

Light could be an important factor as to whether a plant is sensitive to fungal infestation or not. This is a whole new angle because until now only the relationship with the greenhouse climate was considered: perhaps it’s too dry, too wet, too warm or too cold. Even at a high RH a plant doesn’t need to suffer from disease, according to the researchers Jantineke Hofland-Zijlstra and Luc Stevens. They are carrying out fundamental research on plant immunity in relation to light.

ÁFoot-and-mouth disease is a contagious viral disease of cloven-hoofed animals (e.g. cattle, sheep, pigs) and can cause severe economic losses to the farm animal industries. The aim of this thesis was to quantify underlying mechanisms regarding transmission of FMDV. With data from past animal experiments we identified the factors which are associated with the amount of virus shed by infected animals and thus may be of importance for transmission of the virus. In an experimental study, the contribution of the environment on the transmission of FMDV was investigated by using a new mathematical model in which the contribution of the environment on transmission was incorporated. Roughly 44% of the transmission of FMDV occurred through the environment that was contaminated with se-excretions from FMDV infected animals. The role of the different species on the transmission of FMDV was investigated with a transmission study of FMDV between infected sheep and naïve cattle. Sheep were found to be less infectious than cattle but similarly susceptible. Using a so-called next-generation matrix, transmission of FMDV in mixed cattle-sheep populations (with different proportions of cattle and different proportions of vaccinated animals) was quantified and the effects of different vaccination strategies against FMDV were analysed. In mixed populations of cattle and sheep, transmission of FMDV is higher when more cattle are present. In populations with more than 14% cattle, targeting vaccination to cattle only can be sufficient to control FMDV. The results of this thesis show that transmission of FMDV can occur via a contaminated environment, (without animal presence) and that sheep seem to play a limited role in the transmission of FMDV. These results can be used to improve the control measures to prevent and control FMDV in different animal populations.

Leverbotinfecties zijn in toenemende mate een knelpunt bij melkgevende koeien die weiden of vers gras op stal gevoerd krijgen. Leverbotinfecties brengen verliezen met zich mee die onderschat worden, zoals verminderde groei van jongvee, verminderde weerstand, verminderde melkproductie en afkeuring van levers van geslachte dieren.

ÁFoot-and-mouth disease is a contagious viral disease of cloven-hoofed animals (e.g. cattle, sheep, pigs) and can cause severe economic losses to the farm animal industries. The aim of this thesis was to quantify underlying mechanisms regarding transmission of FMDV. With data from past animal experiments we identified the factors which are associated with the amount of virus shed by infected animals and thus may be of importance for transmission of the virus. In an experimental study, the contribution of the environment on the transmission of FMDV was investigated by using a new mathematical model in which the contribution of the environment on transmission was incorporated. Roughly 44% of the transmission of FMDV occurred through the environment that was contaminated with se-excretions from FMDV infected animals. The role of the different species on the transmission of FMDV was investigated with a transmission study of FMDV between infected sheep and naïve cattle. Sheep were found to be less infectious than cattle but similarly susceptible. Using a so-called next-generation matrix, transmission of FMDV in mixed cattle-sheep populations (with different proportions of cattle and different proportions of vaccinated animals) was quantified and the effects of different vaccination strategies against FMDV were analysed. In mixed populations of cattle and sheep, transmission of FMDV is higher when more cattle are present. In populations with more than 14% cattle, targeting vaccination to cattle only can be sufficient to control FMDV. The results of this thesis show that transmission of FMDV can occur via a contaminated environment, (without animal presence) and that sheep seem to play a limited role in the transmission of FMDV. These results can be used to improve the control measures to prevent and control FMDV in different animal populations.

Enkele in Nederland veel voorkomende ziekten bij vissen van de afgelopen twintig jaar. Eel Virus European, Eel Virus European X, Herpesvirus van Paling, Infectieuze Hematopoietische Necrose, Infectieuze Pancreatische Necrose, Koi Herpes Virus, Snoekvirus, Spring Viremia of Carp, Virale Hemorrhagische Septicaemie en Vissen-TBC zijn daar enkele voorbeelden van

Control of Parasitic gastroenteritis in small ruminants is threatened by the worldwide growing problem of anthelmintic resistance. Therfore, alternativeapproaches for worm control are imperative. Of utmost importance is to slow down selection pressure for anthelmintic resistance by using alternative control measure combined with minimal anthelmintic usage. New control options for the Netherlands are discussed.