Modelling the species jump: towards assessing the risk of human infection from novel avian influenzas

The scientific understanding of the driving factors behind zoonotic and pandemic influenzas is hampered by complex interactions between viruses, animal hosts and humans. This complexity makes identifying influenza viruses of high zoonotic or pandemic risk, before they emerge from animal populations, extremely difficult and uncertain. As a first step towards assessing zoonotic risk of Influenza, we demonstrate a risk assessment framework to assess the relative likelihood of influenza A viruses, circulating in animal populations, making the species jump into humans. The intention is that such a risk assessment framework could assist decisionmakers to compare multiple influenza viruses for zoonotic potential and hence to develop appropriate strain-specific control measures. It also provides a first step towards showing proof of principle for an eventual pandemic risk model. We show that the spatial and temporal epidemiology is as important in assessing the risk of an influenza A species jump as understanding the innate molecular capability of the virus.We also demonstrate data deficiencies that need to be addressed in order to consistently combine both epidemiological and molecular virology data into a risk assessment framework

Исследование семантических распределенных параметров информационных компонент системы защиты

A real time quantitative PCR combined with propidium monoazide (PMA) treatment of samples was implemented to quantify live C. jejuni, C. coli and C. lari on broiler chicken carcasses at selected processing steps in the slaughterhouse. The samples were enumerated by culture for comparison. The Campylobacter counts determined with the PMA-qPCR and the culture method were not concordant. We conclude that the qPCR combined with PMA treatment of the samples did not fully reduce the signal from dead cells

High relative humidity pre-harvest reduces post-harvest proliferation of Salmonella in tomatoes

Outbreaks of human illness caused by enteric pathogens such as Salmonella are increasingly linked to the consumption of fruits and vegetables. Knowledge on the factors affecting Salmonella proliferation on fresh produce therefore becomes increasingly important to safeguard public health. Previous experiments showed a limited impact of pre-harvest production practices on Salmonella proliferation on tomatoes, but suggested a significant effect of harvest time. We explored the data from two previously published and one unpublished experiment using regression trees, which allowed overcoming the interpretational difficulties of classical statistical models with higher order interactions. We assessed the effect of harvest time by explicitly modeling the climatic conditions at harvest time and by performing confirmatory laboratory experiments. Across all datasets, regression trees confirmed the dominant effect of harvest time on Salmonella proliferation, with humidity-related factors emerging as the most important underlying climatic factors. High relative humidity the week prior to harvest was consistently associated with lower Salmonella proliferation. A controlled lab experiment confirmed that tomatoes containing their native epimicrobiota supported significantly lower Salmonella proliferation when incubated at higher humidity prior to inoculation. The complex interactions between environmental conditions and the native microbiota of the tomato crop remain to be fully understood

Библиотековедение как фундаментальная наука

The Netherlands saw an unexplained increase in campylobacteriosis incidence between 2003 and 2011, following a period of continuous decrease. We conducted an ecological study and found a statistical association between campylobacteriosis incidence and the annual number of prescriptions for proton pump inhibitors (PPIs), controlling for the patient's age, fresh and frozen chicken purchases (with or without correction for campylobacter prevalence in fresh poultry meat). The effect of PPIs was larger in the young than in the elderly. However, the counterfactual population-attributable fraction for PPIs was largest for the elderly (ca 45% in 2011) and increased at population level from 8% in 2004 to 27% in 2011. Using the regression model and updated covariate values, we predicted a trend break for 2012, largely due to a decreased number of PPI prescriptions, that was subsequently confirmed by surveillance data. Although causality was not shown, the biological mechanism, age effect and trend-break prediction suggest a substantial impact of PPI use on campylobacteriosis incidence in the Netherlands. We chose the ecological study design to pilot whether it is worthwhile to further pursue the effect of PPI on campylobacteriosis and other gastrointestinal pathogens in prospective cohort studies. We now provide strong arguments to do so

Disability Adjusted Life Years and minimal disease: application of a preference-based relevance criterion to rank enteric pathogens

Background: Burden of disease estimates, which combine mortality and morbidity into a single measure, are used increasingly for priority setting in disease control, prevention and surveillance. However, because there is no clear exclusion criterion for highly prevalent minimal disease in burden of disease studies its application may be restricted. The aim of this study was to apply a newly developed relevance criterion based on preferences of a population panel, and to compare burden of disease estimates of five foodborne pathogens calculated with and without application of this criterion. Methods: Preferences for twenty health states associated with foodborne disease were obtained from a population panel (n = 107) with the Visual Analogue Scale and the Time Trade-off (TTO) technique. The TTO preferences were used to derive the relevance criterion: if at least 50% of a panel of judges is willing to trade-off time in order to be restored to full health the health state is regarded as relevant, i.e. TTO median is greater than 0. Subsequently, the burden of disease of each of the five foodborne pathogens was calculated both with and without the relevance criterion. Results: The panel ranked the health states consistently. Of the twenty health states, three did not meet the preference-based relevance criterion. Application of the relevance criterion reduced the burden of disease estimate of all five foodborne pathogens. The reduction was especially significant for norovirus and rotavirus, decreasing with 94% and 78% respectively. Conclusion: Individual preferences elicited with the T

Foodborne diseases from dairy products in developing countries: Hazards and health implications

Dairy products are an important source of high-quality animal proteins in developing countries, and increased consumption of these products by pregnant women and young children is advocated to reduce malnutrition and child stunting. However, the nutritional benefits of dairy products can be compromised by the presence of contaminants causing foodborne disease. These food safety risks are increased by frequent consumption of raw or inadequately heated dairy products. The World Health Organization published estimates of the global burden of foodborne disease in 2015, and attribution of this disease burden to specific food groups in 2017. It is estimated that each year, 600 million people fall ill because of foodborne disease, resulting in 435,000 deaths and a disease burden of 33 million Disability Adjusted Life Years (DALYs; equivalent to one healthy life year lost). Of this burden, 38% is attributed to animal-source foods (ASF), with 12% of the burden of ASF attributed to dairy products. The average global burden of dairy products is 20 DALYs per 100,000 population. The major contaminants in dairy are Mycobacterium bovis (9 DALYs/100,000, highest burden in Africa), Campylobacter spp. (4 DALYs/100,000, highest burden in Eastern Mediterranean), nontyphoidal Salmonella enterica (4 DALYs/100,000, highest burden in Africa) and Brucella spp. (1 DALY/100,000, highest burden in Eastern Mediterranean). The burdens of Cryptosporidium spp., Shiga-toxin producing Escherichia coli and Toxoplasma gondii are low (<1 DALY/100,000). Proper heating of dairy products would be effective in reducing these burdens substantially. The burden of chemical contaminants is less well documented. Adulteration is a potential problem, as illustrated by the melamine contamination incident in Chinese infant formula. Aflatoxin M1 (AFM1) is frequently observed in milk in concentrations higher than maximum tolerable limits in the USA and Europe. AFM1, which cannot be destroyed by heating milk, is a metabolite of aflatoxin B1 (AFB1) - a mycotoxin (fungal toxin) frequently found in corn, nuts, and the feed of dairy animals. However, the carcinogenic potential of AFM1 is significantly lower than that of AFB1, which is a known human liver carcinogen. The risk of liver cancer from current exposure levels to AFM1 is likely to be extremely low. There is limited evidence of an association between AFM1 and stunting, which requires further study. Dioxins cause a high disease burden specifically in Southeast Asia (14 DALYs/100,000); and several metals (lead, arsenic, methylmercury) each cause a global burden of 20-70 DALYs per 100,000. The contribution of dairy products to human exposure to these chemicals is unknown

Архітектурна спадщина Закарпаття під натиском новобуду

Multilocus sequence types (STs) were determined for 232 and 737 Campylobacter jejuni/coli isolates from Dutch travellers and domestically acquired cases, respectively. Putative risk factors for travel-related campylobacteriosis, and for domestically acquired campylobacteriosis caused by exotic STs (putatively carried by returning travellers), were investigated. Travelling to Asia, Africa, Latin America and the Caribbean, and Southern Europe significantly increased the risk of acquiring campylobacteriosis compared to travelling within Western Europe. Besides eating chicken, using antacids, and having chronic enteropathies, we identified eating vegetable salad outside Europe, drinking bottled water in high-risk destinations, and handling/eating undercooked pork as possible risk factors for travel-related campylobacteriosis. Factors associated with domestically acquired campylobacteriosis caused by exotic STs involved predominantly person-to-person contacts around popular holiday periods. We concluded that putative determinants of travel-related campylobacteriosis differ from those of domestically acquired infections and that returning travellers may carry several exotic strains that might subsequently spread to domestic populations even through limited person-to-person transmission

Community incidence of pathogen-specific gastroenteritis: reconstructing the surveillance pyramid for seven pathogens in seven European Union member states.

By building reconstruction models for a case of gastroenteritis in the general population moving through different steps of the surveillance pyramid we estimated that millions of illnesses occur annually in the European population, leading to thousands of hospitalizations. We used data on the healthcare system in seven European Union member states in relation to pathogen characteristics that influence healthcare seeking. Data on healthcare usage were obtained by harmonized cross-sectional surveys. The degree of under-diagnosis and underreporting varied by pathogen and country. Overall, underreporting and under-diagnosis were estimated to be lowest for Germany and Sweden, followed by Denmark, The Netherlands, UK, Italy and Poland. Across all countries, the incidence rate was highest for Campylobacter spp. and Salmonella spp. Incidence estimates resulting from the pyramid reconstruction approach are adjusted for biases due to different surveillance systems and are therefore a better basis for international comparisons than reported data