The disease burden associated with Campylobacter spp. in Germany, 2014.

Bacteria of the genus Campylobacter are an important cause of human illness worldwide. Campylobacter infections are expressed as gastroenteritis and can lead to severe sequelae like reactive arthritis, Guillain-Barré syndrome, irritable bowel syndrome and inflammatory bowel disease. In Germany, Campylobacter-associated gastroenteritis cases are notifiable but there is no reporting obligation for the sequelaes and the disease burden is clearly underestimated. The aim of our study was to quantify reliably the current disease burden of all Campylobacter spp.-associated diseases for Germany with the method of disability-adjusted life years (DALYs). DALYs combine mortality and morbidity in a single summary measure, whereby one DALY represents the loss of one year in full health. For acute gastroenteritis, we estimated 967 DALYs of which only 484 DALYs were detected within the reporting system. Overall, we estimated that 8811 DALYs were caused by the campylobacter-related diseases known so far. 98% of the DALYs were associated with morbidity and 2% with mortality. Mortality was caused by the health outcomes Gastroenteritis and Guillain-Barré syndrome exclusively.

[Systematic Review of the Burden of Campylobacter-associated Disease]. / Systematischer Review zur Krankheitslast durch Campylobacter spp.

Bacteria of the genus Campylobacter spp. are one of the most common causes of gastroenteritis and can lead to serious sequelae. Several studies have estimated the disease burden of Campylobacter spp. with the quantitative metric of disability-adjusted life years (DALY). The aim of this systematic review is to give an overview of the information available about different countries and periods for which DALYs were calculated and how the different results are comparable. One of the most important transmission pathways for Campylobacter spp. is food. Therefore, special attention was given to studies that only estimated the foodborne disease burden of Campylobacter bacteria. With a systematic search for the period 1/1996-6/2016, one worldwide and 21 country-specific publications of the WHO were identified. Because of the different methods and the quality of the different data sets, the estimated results of all Campylobacter health outcomes of the country-specific studies vary from 0.4 DALYs per 100000 people in France to 109 DALY per population in Poland. The calculation of the attributable foodborne disease burden was based on the estimations of the incidences of all Campylobacter health outcomes with the associated uncertainty for each result. So the estimations of the foodborne disease burden show a large range from 0.5 DALYs per 100000 people in Greek to 21.2 DALYs per 100000 people in New Zealand. This span can only be partially explained by the country-specific variability in the food production, the consumption behavior and the incidence of Campylobacter bacteria.

Disease burden of methylmercury in the German birth cohort 2014.

This study aimed to estimate the disease burden of methylmercury for children born in Germany in the year 2014. Humans are mainly exposed to methylmercury when they eat fish or seafood. Prenatal methylmercury exposure is associated with IQ loss. To quantify this disease burden, we used Monte Carlo simulation to estimate the incidence of mild and severe mental retardation in children born to mothers who consume fish based on empirical data. Subsequently, we calculated the disease burden with the disability-adjusted life years (DALY)-method. DALYs combine mortality and morbidity in one measure and quantify the gap between an ideal situation, where the entire population experiences the standard life expectancy without disease and disability, and the actual situation. Thus, one DALY corresponds to the loss of one year of life in good health. The methylmercury-induced burden of disease for the German birth cohort 2014 was an average of 14,186 DALY (95% CI 12,915-15,440 DALY). A large majority of the DALYs was attributed to morbidity as compared to mortality. Of the total disease burden, 98% were attributed to mild mental retardation, which only leads to morbidity. The remaining disease burden was a result of severe mental retardation with equal proportions of premature death and morbidity.

A probabilistic model for the carry-over of PCDD/Fs from feed to growing pigs.

When food producing animals are contaminated with PCDD/F congeners, information on the contaminant's concentration in the bodies of the animals at time of slaughter is needed for risk management purposes. We have developed a mathematical model for the kinetics of PCDD/Fs in growing pigs in case of contaminated feed fed for a limited duration of time. This model allows the prediction of concentrations in body fat. It considers absorption fractions of PCDD/Fs, clearance by metabolism, dilution by growth and excretion through fecal fat. The model parameters were calibrated by fitting the model to experimental data. On the basis of this toxicokinetic model a probabilistic model has been constructed. The probabilistic model handles the parameters with appropriate probability distributions and Monte-Carlo simulation technique, providing for realistic situations with many animals and a range of contaminations and feeding intervals. We applied the new model to describe the German dioxin incident of winter 2010/2011 and discuss its viability as decision tool. The approach demonstrated here is a showcase how a risk assessment in the case of contaminated feeding can be performed.

Graphical models and Bayesian domains in risk modelling: application in microbiological risk assessment.

Quantitative microbiological risk assessment (QMRA) models are used to reflect knowledge about complex real-world scenarios for the propagation of microbiological hazards along the feed and food chain. The aim is to provide insight into interdependencies among model parameters, typically with an interest to characterise the effect of risk mitigation measures. A particular requirement is to achieve clarity about the reliability of conclusions from the model in the presence of uncertainty. To this end, Monte Carlo (MC) simulation modelling has become a standard in so-called probabilistic risk assessment. In this paper, we elaborate on the application of Bayesian computational statistics in the context of QMRA. It is useful to explore the analogy between MC modelling and Bayesian inference (BI). This pertains in particular to the procedures for deriving prior distributions for model parameters. We illustrate using a simple example that the inability to cope with feedback among model parameters is a major limitation of MC modelling. However, BI models can be easily integrated into MC modelling to overcome this limitation. We refer a BI submodel integrated into a MC model to as a "Bayes domain". We also demonstrate that an entire QMRA model can be formulated as Bayesian graphical model (BGM) and discuss the advantages of this approach. Finally, we show example graphs of MC, BI and BGM models, highlighting the similarities among the three approaches.

Risk assessment in fish welfare, applications and limitations.

The Treaty of Amsterdam, in force since 1 May 1999, has established new ground rules for the actions of the European Union (EU) on animal welfare. It recognizes that animals are sentient beings and obliges the European Institutions to pay full regard to the welfare requirements of animals when formulating and implementing Community legislation. In order to properly address welfare issues, these need to be assessed in a scientific and transparent way. The principles of risk assessment in terms of transparency and use of available scientific data are probably well suited for this area. The application of risk assessment for terrestrial and aquatic animal welfare is a relatively new area. This paper describes the work developed in the context of the European Food Safety Authority (EFSA) opinions on the application of a risk assessment methodology to fish welfare. Risk assessment is a scientifically based process that seeks to determine the likelihood and consequences of an adverse event, which is referred to as a hazard. It generally consists of the following steps: (i) hazard identification, (ii) hazard characterisation, (iii) exposure assessment and (iv) risk characterisation. Different approaches can be used for risk assessments, such as qualitative, semi-quantitative and quantitative approaches. These are discussed in the context of fish welfare, using examples from assessments done to aquaculture husbandry systems and stunning/killing methods for farmed fish. A critical review of the applications and limitations of the risk methodology in fish welfare is given. There is a need to develop appropriate indicators of fish welfare. Yet, risk assessment methodology provides a transparent approach to identify significant hazards and support recommendations for improved welfare.

Expert opinion based modelling of the risk of human infection with H5N1 through the consumption of poultry meat in Germany.

According to current scientific opinion the risk of human infection with H5N1 via preparation and consumption of poultry meat is negligible.This opinion has not yet been challenged by a formal risk assessment, due to the lack of empirical data. We have developed a scenario pathway model as a conceptual framework for a formal assessment of the H5N1 risk to humans through consumption of poultry meat and parameterise the model using information derived from expert opinions. The aim of this study was to investigate whether the notion of an overall negligible risk via the oral infection route is consistent with ad hoc data and expert opinions on the relevant parameters of the model. The model is mainly based on expert opinion. A stochastic Monte-Carlo simulation was conducted which took into consideration (amongst others) the exposure and infection of chicken (broiler and layer), turkeys, ducks and geese, the probabilities of detection prior to slaughter, virus survival and contamination during slaughter, as well as during the cutting and preparation of meat in commercial plants and in private households, respectively. The empirical consumption pattern for poultry meat in Germany was taken into account in the simulation. The results show that the risk for the individual consumer is practically zero whereas up to 23 cases per year in Germany might occur if the upper (more pessimistic) ranges of the expert opinions apply. The finding of a low but non-negligible risk to the population is discussed in relation to the epidemiological information available from recent outbreaks in South East Asia.