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After the first introduction of African swine fever (ASF) in the European Union in 2014, the ASF virus (ASFV) has steadily spread in the European Union. The virus has occasionally been transmitted over unexpectedly large distances that are believed to be related to human-mediated spread. Hunting tourism has been mentioned as a potential contributor to these long-distance jumps, although evidence is lacking. In this study, the possible role of hunters carrying ASFV-contaminated wild boar products (WBP) from hunting trips in affected countries was evaluated. A quantitative risk model was developed to estimate the expected annual number of ASF exposures of wild boar and domestic pigs in the Netherlands via this introduction route. Main input data into the model were the ASF prevalence in hunted wild boar, the number and destination of hunting trips of Dutch hunters, and the probabilities that hunters take WBP home and dispose leftovers such that wild boar or domestic pigs have access. The model indicated that the total expected annual number of exposures (wild boar and domestic pigs together) in the Netherlands is 0.048 (95% uncertainty interval 7.5 × 10−3 – 0.15). Model results were most sensitive to uncertainty on leftovers fed to domestic pigs (swill feeding), which is an illegal practice. Uncertainties on the ASF prevalence of hunted wild boar and the probabilities that hunters take WBP home also impacted model results. Default model results were based on the 2019 situation. Alternative scenarios were run with the model to account for the change of ASF status of Belgium (recovery of ASF-free status) and Germany (ASF-infected) in 2020. Results indicated that especially the presence of ASF in Germany increased the incursion risk. However, this increase might be counteracted by a change in travel behavior of hunters.

In the veal industry in The Netherlands, each year around 1.2 million “white” veal calves are produced on around 1100 farms. Bovine respiratory disease (BRD) causes serious health issues in these calves, also resulting in high usage of antimicrobials. To reduce antimicrobial usage, a more targeted treatment regime is needed, for which it is necessary to identify the causative agent. This study aimed at determining associations between pathogens and clinical disease, between prevalence of pathogens and BRD outbreaks, and BRD and performance. A cohort study was conducted involving ten veal farms, in which calf respiratory health was evaluated for the first 12 weeks. Whenever there was an outbreak of BRD, as determined by the farm veterinary surgeon, samples were taken from diseased and control calves through broncho-alveolar lavage. From these samples a broad spectrum of micro-organisms were isolated. Performance data were also collected. A total of 23 outbreaks happened during the 12 week study period, mostly in the first six weeks. BRD associated pathogens found were: BHV1, BPI3V, BRSV, BVDV, Pasteurella multocida, Mannheimia haemolytica, Trueperella pyogenes, Histophilus somni, Mycoplasma bovis, Mycoplasma bovirhinis and Mycoplasma dispar. For most BRD associated pathogens, there was no clear association between presence or prevalence of the micro-organisms and clinical issues. Only T. pyogenes (7.4% in healthy, 14.6% in diseased calves, p 0.013), M. bovis (37.6% and 63.2% respectively, p 0.001) and BVDV (9.9% and 16.9% respectively, p 0.03) were found more often in diseased animals. BPI3V was found in a few early outbreaks, which might suggest involvement in early outbreaks. It appears to be difficult to associate specific pathogens to outbreaks at the species level. BRD is the major reason for treatment with antimicrobials. More specific knowledge about the association between pathogens and health/disease could help to reduce antimicrobial use.

To facilitate decisions on risk management for exotic animal disease threats, a rapid risk assessment tool (RRAT) was developed to quickly assess the ever-changing risk of animal disease introduction. The objective of the tool is to prioritize diseases for risk management and to identify high risk trade flows and source countries. RRAT has been built as a relational database to link data on disease outbreaks worldwide, on pathways for introduction and on disease-specific parameters. The tool has been parameterized to assess the incursion risk of ten exotic animal diseases for the Netherlands by two pathways, i.e. trade in live nimals and import of animal products. RRAT calculates a semi-quantitative risk score for the incursion risk of each disease, the results of which allow for prioritization. Results based on the 2018 situation indicate that bovine tuberculosis has the highest risk of being introduced into the Netherlands by both introduction pathways. Trade in live animals also entails a risk for equine infectious anemia and bluetongue, whereas import of animal products also has a high risk for African swine fever, Aujeszky’s disease and foot and mouth disease. We conclude that RRAT is a powerful tool to quickly analyze the incursion risk of multiple animal diseases. Inclusion of additional pathways will increase the reliability of results, especially when import of livestock is banned from infected areas.

Generic risk assessment (RA) tools can be applied to assess the incursion risk of multiple animal diseases, allowing for a rapid response to a variety of newly emerging or re-emerging diseases. To explore the opportunities for cross-validation of generic RA tools, seven tools were used to assess the incursion risk of African swine fever (ASF) for the Netherlands and Finland for the 2017 situation 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. The tools had different outputs and endpoints and therefore the cross-validation focused on the relative risks across countries and scenarios. All tools evaluated the risk to the Netherlands to be higher than Finland for the live animal trade pathway. The risk to Finland was the same or higher as the Netherlands for the wild boar pathway, but the tools were inconclusive on the animal products pathway. All tools agreed that the hypothetical presence of ASF in Germany increased the risk for the Netherlands, but not for Finland. The case study illustrated that conclusions on the ASF risk were similar across the generic RA tools, despite differences observed in calculated risks. Hence, it was concluded that the cross-validation contributed to the credibility of their results.

Background: The parasite Toxoplasma gondii (T. gondii) causes a substantial human disease burden worldwide. Ingesting improperly cooked pork containing T. gondii is considered one of the major sources of human infection in Europe and North America. Consequently, control of T. gondii infections in pigs is warranted. The European Food Safety Authority advised to perform serological monitoring of pigs and to conduct farm audits for the presence of risk factors. Serological monitoring was implemented in several Dutch slaughterhouses, one to six blood samples (a total of 5134 samples) were taken from each delivery of finishing pigs and samples were tested for the presence of anti-T. gondii antibodies. Using these test results, a cross-sectional study was initiated to assess the association between the within-herd T. gondii seroprevalence and the presence of risk factors for T. gondii infections at 69 conventional finishing pig farms in the Netherlands.Results: A multivariable model showed significant (P ≤ 0.05) association with twelve potential risk factors: type of farm, presence of dogs, presence of ruminants, use of boots, use of shower and farm clothing, mode of rodent control, bedding accessibility for rodents, presence of cats, type of drinking water, heating of the feed, use of goat whey and shielding of birds.Conclusions: Serological monitoring of finishing pigs for T. gondii in slaughterhouses can be used to identify the presence of T. gondii risk factors on Dutch conventional finishing pig farms and seems a valuable tool to guide and monitor the control of T. gondii in pork production.

BackgroundThe parasite Toxoplasma gondii (T. gondii) is recognized as one of the major foodborne pathogens with a high human disease burden. To control T. gondii infections in pigs, European Food Safety Agency (EFSA) advises serological testing of pigs and audits of pig farms to identify risk factors for T. gondii infection. In line with this approach, the aim of the current study was to assess the effectiveness and costs of intervention measures implemented to reduce the T. gondii seroprevalence on finishing pig farms in the Netherlands. A crossover clinical trial was conducted at five case farms were their own control and the cross-over moment was the implementation of interventions to reduce risk factors. Each of the case farms had a farm-specific intervention strategy with one principal intervention measure (neutering of cats, professional rodent control or covering food storage).ResultsAll finishing pig farms (n = 5) showed a reduction in T. gondii seroprevalence within one year of implementing the intervention strategy. Cat neutering (n = 3) and feed coverage (n = 1) showed statistically significant reductions in seroprevalence. Rodent control (n = 1) did not show a statistically significant reduction. The estimated reduction in seroprevalence in response to the neutering of cats and feed coverage were 67 and 96 %, respectively.ConclusionsOur work demonstrates that it is possible to reduce the within-farm T. gondii seroprevalence within one year after interventions were implemented to reduce T. gondii risk factors. This information is essential and encouraging for policy makers, food business operators, and farmers to implement in their risk assessment and to apply to food safety control systems.

Campylobacter remains the most common reported zoonotic pathogen in humans in the European Union since 2008 (EFSA, 2018). Poultry is a major source of human infection with Campylobacter, although the epidemiology of Campylobacter at broiler farms is still poorly understood. The purpose of the study was to investigate factors associated with the presence of Campylobacter on a selected number of broiler farms in the Netherlands. The investigations were conducted starting from spring/summer 2017 until autumn 2018. Faecal samples were collected on a weekly basis at 21 farms, from one, two or three houses. There were 38 houses participating in the study. Information on flock and farm characteristics including biosecurity measures was gathered via a questionnaire (CAMPAS) and food chain information forms (VKI forms). In addition activities (other than routine activities) at the farms were described by the farmers in log books. The collected data were used as putative variables for a risk factors analysis. In total 284 flocks were sampled of which 32% were positive for Campylobacter. A multivariate logistic regression model revealed three factors associated with presence of Campylobacter in broiler flocks. They included summer/autumn season, mowing premises in the surroundings of the farm and the previous Campylobacter positive flock in the house. Although the factor breed did not remain in the final model, there was a difference in the time of becoming infected between regular and slow growing breeds. With the available data set the thinning practice was not confirmed as a risk factor. Evaluation of the outcome of the biosecurity questionnaire (CAMPAS) revealed an association between both poor hygienic practices on farm as well as the number of houses on farms with Campylobacter presence. Some indicators addressed in the questionnaire however need adjustment to be used as a predictive tool for introduction of Campylobacter on broiler farms. More studies are needed to furt

Toxoplasma gondii is the causative agent of the parasitic disease toxoplasmosis, which is an important foodborne zoonosis. Eating undercooked meat of infected animals, including pigs, has been considered the major transmission route of T. gondii to humans. Therefore, it is urgent to develop and implement intervention measures in the pork meat chain to reduce risks of acquiring a T. gondii infection. Proposed measures for control of T. gondii in pigs include serological testing of pigs and audits of pig farms on risk factors for T. gondii infection. So far, these ideas have not been tested in practice. In order to generate knowledge about the epidemiology and seroprevalence of T. gondii, as a basis for developing a surveillance system, we studied the long term seroprevalence over years, farming systems and regions, and seasonal patterns of T. gondii seroprevalence in Dutch slaughter pigs. During a five year study period from 2012 to 2016, serum samples were routinely collected in five Dutch pig slaughterhouses. The sera were tested in an ELISA for the presence of antibodies against Toxoplasma. In total 226,340 serum samples were collected and tested during the study period. The observed seroprevalence varied over years, with the highest overall seroprevalence in 2014 (2.8%) and the lowest in 2016 (1.4%). A higher seroprevalence was observed in pigs from organic farms compared to pigs from conventional farms. The overall risk of infection was on average 2.63 times significantly (p < 0.001) higher for organically raised pigs than for conventionally raised pigs. A seasonal pattern in seroprevalence was observed: the results showed a dominant annual periodicity with a seroprevalence peak in winter around week 1 and a minimum seroprevalence in summer around week 27. To our knowledge, this is the first large scale study on the seroprevalence of T. gondii in slaughter pigs. In comparison to other European serological studies, the observed seroprevalence seems to be relative

The objective of the G‐RAID project was the mutual exchange of knowledge between the consortium members on the development of generic risk assessment (RA) tools for animal disease incursion. Seven generic RA tools were compared considering objectives, inputs, algorithms and outputs. All tools were designed for rapid risk assessment and could assess the incursion risk for multiple diseases and pathways. Specific objectives of the tools, however, varied from immediate response to new disease events to prioritization of diseases and horizon scanning, resulting in different approaches to evaluate the incursion risk of infectious animal diseases. Cross‐validation was explored as a method to validate the generic RA tools. All tools were applied to a case study for African swine fever (ASF) in which the incursion risk for the Netherlands and Finland was assessed for the 2017 situation and two hypothetical scenarios with ASF cases reported in Germany. The generic RA tools were parameterized using the same global databases for disease occurrence and trade in live animals and animal products. Disease‐related parameters, however, could not be standardized because of the different levels of detail included in the model calculations. A comparison of absolute results of the tools was not possible, because output parameters represented different endpoints, varied from qualitative probability levels to quantitative numbers, and were expressed in different units. Therefore, relative risks across countries and scenarios were calculated for each tool and compared. The risk assessment tools largely agreed upon the ranking of countries and scenarios based on relative risks and would thus indicate similar priorities for risk management As such, the cross‐validation increased the credibility of results obtained with the generic RA tools. The cross‐validation also contributed to the internal validation and further development of the tools. Results from the G‐RAID project were disseminated

This paper describes a study aimed at quantification of the prevalence of several known bacterial and viral pathogens, clinical signs and additional conditions leading to Bovine Respiratory Disease (BRD) in veal calves in the Netherlands. For this purpose 168 veal calves with a respiratory rate (RR) higher than 50 rates per minute (cases) and 573 calves with a RR lower than 50 rates per minute (case-controls) were subjected to bronchoalveolair lavages (BAL’s) and clinical evaluations, on conventional Dutch veal farms. The most prevalent pathogen was Pasteurella multocida, detected in 29% of cases and in 33% of case-controls. Statistically, Arcanobacterium pyogenes, Bovine Parainfluenza and Bovine Viral Diarrhea Virus had higher a prevalence in cases than in case-controls. Clinical signs were significantly more often detected in cases, in both viral and bacterial pathogens. Of the cases 45% had an elevated rectal temperature, 24% was in respiratory distress, but just 6% showed coughing. Analysis showed there was no significance between severity of clinical signs and a specific pathogen related to BRD in cases and case-controls.

Toxoplasma gondii is recognized as one of the major foodborne pathogens. The European Food Safety Authority (EFSA) concluded that T. gondii is one of the public health hazards in pigs to be covered within a modern meat inspection and advised to include serological testing of pigs and audits of pig farms to control T. gondii. A project is presented that develops a framework where this idea is practically implemented in a pork supply chain. The aim of the program is to reduce the contribution from the pork chain to the human toxoplasmosis disease burden. In the pilot at least one blood sample per batch at delivery at the slaughterhouse is tested with a Toxoplasma Elisa. With this screening 20 (1%) high risk herds were identified. These high risk farms and their controls, 2 per high risk farm, were followed up. More samples of risk farms and their controls were collected to get a better estimate of the within herd prevalence and to follow the development of serology over time. Additional MC-PCR was performed on hearts of pigs from these herds to confirm presence of infection, tissue cysts. Also farm assessments were done to verify the presence of risk factors at the identified farms. In the first farm where hearts were tested by PCR the presence of toxoplasma tissue cysts was shown. The results give insight in how risk based approaches with food chain information (FCI) for animals sent to slaughter could work, by substantiating how risk herds can be practically identified and which interventions are feasible. The results are discussed in the perspective of human health risks.

In intra-EU trade, the health status of animals is warranted by issuing a health certificate after clinical inspection in the exporting country. This certificate cannot provide guarantee of absence of infection, especially not for diseases with a long incubation period and no overt clinical signs such as bovine tuberculosis (bTB). The Netherlands are officially free from bTB since 1999. However, frequent reintroductions occurred in the past 15 years through importation of infected cattle. Additional testing (AT) of imported cattle could enhance the probability of detecting an imported bTB infection in an early stage. The goal of this study was to evaluate the effectiveness of risk-based AT for bTB in cattle imported into The Netherlands.A generic stochastic import risk model was developed that simulates introduction of infection into an importing country through importation of live animals. Main output parameters are the number of infected animals that is imported (Ninf), the number of infected animals that is detected by testing (Ndet), and the economic losses incurred by importing infected animals (loss). The model was parameterized for bTB. Model calculations were optimized to either maximize Ndet or to minimize loss.Model results indicate that the risk of bTB introduction into The Netherlands is very high. For the current situation in which Dutch health checks on imported cattle are limited to a clinical inspection of a random sample of 5–10% of imported animals, the calculated annual Ninf = 99 (median value). Random AT of 8% of all imported cattle results in Ndet = 7 (median value), while the median Ndet = 75 if the sampling strategy for AT is optimized to maximize Ndet. However, in the latter scenario, loss is more than twice as large as in the current situation, because only calves are tested for which cost of detection is higher than the expected gain of preventing a possible outbreak. When optimizing the sampling strategy for AT to minimize loss, only breed