Suchergebnisse

Foot‐and‐mouth disease (FMD) is a viral disease of domesticated and wild cloven‐hoofed animals. FMD virus is known to spread by direct contact between infected and susceptible animals, by animal products such as meat and milk, by the airborne route, and mechanical transfer on people, wild animals, birds, and by vehicles. During the outbreak of 2001 in the Netherlands, milk from dairy cattle was illegally discharged into the sewerage as a consequence of transport prohibition. This may lead to contaminated discharges of biologically treated and raw sewage in surface water that is given to cattle to drink. The objective of the present study was to assess the probability of infecting dairy cows that were drinking FMD virus contaminated surface water due to illegal discharges of contaminated milk. So, the following data were collected from literature: FMD virus inactivation in aqueous environments, FMD virus concentrations in milk, dilution in sewage water, virus removal by sewage treatment, dilution in surface water, water consumption of cows, size of a herd in a meadow, and dose‐response data for ingested FMD virus by cattle. In the case of 1.6 × 102 FMD virus per milliliter in milk and discharge of treated sewage in surface water, the probability of infecting a herd of cows was estimated to be 3.3 × 10−7 to 8.5 × 10−5, dependent on dilution in the receiving surface water. In the case of discharge of raw sewage, all probabilities of infection were 100 times higher. In the case of little dilution in small rivers, the high level of 8.5 × 10−3 is reached. For 104 times higher FMD virus concentrations in milk, the probabilities of infecting a herd of cows are high in the case of discharge of treated sewage (3.3 × 10−3 to 5.7 × 10−1) and very high in the case of discharge of raw sewage (0.28–1.0). It can be concluded that illegal and uncontrolled discharges of contaminated milk into the sewerage system may lead to high risks to other cattle farms at 6–50 km distance of the location of discharge within one day. This clearly underlines current measures that prohibit such discharges, and also asks for strict control. This risk assessment clearly demonstrated the potential significance of FMD virus transmission via water, and the results will be useful on an international scale, and could also serve as a basis for other FMD risk‐assessment models.

Quantitative microbiological risk assessment was used to quantify the risk associated with the exposure to Legionella pneumophila in a whirlpool. Conceptually, air bubbles ascend to the surface, intercepting Legionella from the traversed water. At the surface the bubble bursts into dominantly noninhalable jet drops and inhalable film drops. Assuming that film drops carry half of the intercepted Legionella, a total of four (95% interval: 1–9) and 4.5×104 (4.4×104 – 4.7×104) cfu/min were estimated to be aerosolized for concentrations of 1 and 1,000 legionellas per liter, respectively. Using a dose‐response model for guinea pigs to represent humans, infection risks for active whirlpool use with 100 cfu/L water for 15 minutes were 0.29 (∼0.11–0.48) for susceptible males and 0.22 (∼0.06–0.42) for susceptible females. A L. pneumophila concentration of ≥1,000 cfu/L water was estimated to nearly always cause an infection (mean: 0.95; 95% interval: 0.9–∼1). Estimated infection risks were time‐dependent, ranging from 0.02 (0–0.11) for 1‐minute exposures to 0.93 (0.86–0.97) for 2‐hour exposures when the L. pneumophila concentration was 100 cfu/L water. Pool water in Dutch bathing establishments should contain <100 cfu Legionella/L water. This study suggests that stricter provisions might be required to assure adequate public health protection.

Sources for human hepatitis E virus (HEV) infections of genotype 3 are largely unknown. Pigs are potential animal reservoirs for HEV. Intervention at pig farms may be desired when pigs are confirmed as a source for human infections, requiring knowledge about transmission routes. These routes are currently understudied. The current study aims to quantify the likelihood of pig feces in causing new HEV infections in pigs due to oral ingestion. We estimated the daily infection risk for pigs by modeling the fate of HEV in the fecal–oral (F–O) pathway. Using parameter values deemed most plausible by the authors based on current knowledge the daily risk of infection was 0.85 (95% interval: 0.03–1). The associated expected number of new infections per day was ∼4 (2.5% limit 0.1, the 97% limit tending to infinity) compared to 0.7 observed in a transmission experiment with pigs, and the likelihood of feces causing the transmission approached 1. In alternative scenarios, F–O transmission of HEV was also very likely to cause new infections. By reducing the total value of all explanatory variables by 2 orders of magnitude, the expected numbers of newly infected pigs approached the observed number. The likelihood of F–O transmission decreased by decreasing parameter values, allowing for at most 94% of infections being caused by additional transmission routes. Nevertheless, in all scenarios F–O transmission was estimated to contribute to HEV transmission. Thus, despite the difficulty in infecting pigs with HEV via oral inoculation, the F–O route is likely to cause HEV transmission among pigs.

Climate change may impact waterborne and foodborne infectious disease, but to what extent is uncertain. Estimating climate‐change‐associated relative infection risks from exposure to viruses, bacteria, or parasites in water or food is critical for guiding adaptation measures. We present a computational tool for strategic decision making that describes the behavior of pathogens using location‐specific input data under current and projected climate conditions. Pathogen‐pathway combinations are available for exposure to norovirus, Campylobacter, Cryptosporidium, and noncholera Vibrio species via drinking water, bathing water, oysters, or chicken fillets. Infection risk outcomes generated by the tool under current climate conditions correspond with those published in the literature. The tool demonstrates that increasing temperatures lead to increasing risks for infection with Campylobacter from consuming raw/undercooked chicken fillet and for Vibrio from water exposure. Increasing frequencies of drought generally lead to an elevated infection risk of exposure to persistent pathogens such as norovirus and Cryptosporidium, but decreasing risk of exposure to rapidly inactivating pathogens, like Campylobacter. The opposite is the case with increasing annual precipitation; an upsurge of heavy rainfall events leads to more peaks in infection risks in all cases. The interdisciplinary tool presented here can be used to guide climate change adaptation strategies focused on infectious diseases.

Swimming ponds are artificial ecosystems for bathing in which people imitate the conditions of natural waters. Swimming in natural water may pose health risks if the water quality is microbiologically poor. Swimming ponds are small water bodies that may be used by relatively large groups of people, moreover, the water is not disinfected, e.g. by using chlorine. The draft new swimming pool legislation in the Netherlands includes water quality requirements for swimming ponds. This study focused on the examination and evaluation of the new microbiological water quality requirements, including Escherichia coli, intestinal enterococci, Pseudomonas aeruginosa and Staphylococcus aureus, in thirteen public swimming pools. In eight of thirteen swimming ponds the water quality met the requirements for fecal indicators; 93–95% of the samples met the requirement for E. coli (≤100/100 ml) and intestinal enterococci (≤50/100 ml). The requirement for P. aeruginosa (≤10/100 ml) was met in eleven of thirteen swimming ponds (99% of the samples). In 68% of the samples the requirement for S. aureus (<1/100 ml) was met. A linear mixed effect analysis showed that E. coli and intestinal enterococci concentrations were significantly dependent on the log10 of turbidity. P. aeruginosa concentrations were significantly dependent on water temperature. 31–45% of the variation between swimming ponds was explained by considering 'pond' as a random effect in the analysis. The monitoring of microbiological parameters in swimming pond water needs selective analytical methods, such as those used in this study, due to large numbers of background bacteria. The draft new Dutch swimming pool legislation provides proper guidance to ensure the microbiological safety of swimming pond water; it would benefit from inclusion of turbidity as an extra parameter. S. aureus is a relevant parameter for non-fecal shedding, although scientific literature does not provide evidence for a norm value based on a dose-response relation for exposure to S. aureus in ...

Projected plastic production volumes are rising, as is societal and political attention to plastic pollution and possible health impacts. In line with ambitions for climate mitigation and the circular economy, various national and international policies and action plans address the reduction of impacts of plastics. Quantitative scenario analyses show that even if current ambitious targets to reduce plastics are achieved, plastics will remain a source of millions of tons of environmental pollution annually. To achieve a sustainable transformation of the global plastics economy, 'extraordinary effort' and 'coordinated global action' beyond current ambitions are needed. While mapping knowledge gaps for the effects of micro and nano plastics (MNP) is crucial, mapping alone is not enough to achieve the needed transition. In this communication, we propose a scope for the exploration of societal transformation pathways to safe and sustainable plastics. To see which efforts are needed globally we need to advance in the following three areas: (i) embedding risk assessment methodologies in wider cost-benefit and life cycle analyses; (ii) using safe-and-sustainable design strategies that include alternative solutions and look at multiple life cycles, and (iii) reflecting on the societal transformation pathways with stakeholders by using co-created quantitative models. We believe that these practices are crucial in the coming decade to realise the extraordinary effort of defining safe and sustainable plastics.

Projected plastic production volumes are rising, as is societal and political attention to plastic pollution and possible health impacts. In line with ambitions for climate mitigation and the circular economy, various national and international policies and action plans address the reduction of impacts of plastics. Quantitative scenario analyses show that even if current ambitious targets to reduce plastics are achieved, plastics will remain a source of millions of tons of environmental pollution annually. To achieve a sustainable transformation of the global plastics economy, 'extraordinary effort' and 'coordinated global action' beyond current ambitions are needed. While mapping knowledge gaps for the effects of micro and nano plastics (MNP) is crucial, mapping alone is not enough to achieve the needed transition. In this communication, we propose a scope for the exploration of societal transformation pathways to safe and sustainable plastics. To see which efforts are needed globally we need to advance in the following three areas: (i) embedding risk assessment methodologies in wider cost-benefit and life cycle analyses; (ii) using safe-and-sustainable design strategies that include alternative solutions and look at multiple life cycles, and (iii) reflecting on the societal transformation pathways with stakeholders by using co-created quantitative models. We believe that these practices are crucial in the coming decade to realise the extraordinary effort of defining safe and sustainable plastics.

The debate over the suitability of molecular biological methods for the enumeration of regulatory microbial parameters (e.g. Faecal Indicator Organisms [FIOs]) in bathing waters versus the use of traditional culture-based methods is of current interest to regulators and the science community. Culture-based methods require a 24-48 hour turn-around time from receipt at the laboratory to reporting, whilst quantitative molecular tools provide a more rapid assay (approximately 2-3 h). Traditional culturing methods are therefore often viewed as slow and 'out-dated', although they still deliver an internationally 'accepted' evidence-base. In contrast, molecular tools have the potential for rapid analysis and their operational utility and associated limitations and uncertainties should be assessed in light of their use for regulatory monitoring. Here we report on the recommendations from a series of international workshops, chaired by a UK Working Group (WG) comprised of scientists, regulators, policy makers and other stakeholders, which explored and interrogated both molecular (principally quantitative polymerase chain reaction [qPCR]) and culture-based tools for FIO monitoring under the European Bathing Water Directive. Through detailed analysis of policy implications, regulatory barriers, stakeholder engagement, and the needs of the end-user, the WG identified a series of key concerns that require critical appraisal before a potential shift from culture-based approaches to the employment of molecular biological methods for bathing water regulation could be justified. ; Additional co-authors: Lidija Globevnik, Valerie J. Harwood, Chris J. Hodgson, David N. Lees, Gordon L. Nichols, Andreas Nocker, Ciska Schets

The debate over the suitability of molecular biological methods for the enumeration of regulatory microbial parameters (e.g. Faecal Indicator Organisms [FIOs]) in bathing waters versus the use of traditional culture-based methods is of current interest to regulators and the science community. Culture-based methods require a 24–48 hour turn-around time from receipt at the laboratory to reporting, whilst quantitative molecular tools provide a more rapid assay (approximately 2–3 h). Traditional culturing methods are therefore often viewed as slow and 'out-dated', although they still deliver an internationally 'accepted' evidence-base. In contrast, molecular tools have the potential for rapid analysis and their operational utility and associated limitations and uncertainties should be assessed in light of their use for regulatory monitoring. Here we report on the recommendations from a series of international workshops, chaired by a UK Working Group (WG) comprised of scientists, regulators, policy makers and other stakeholders, which explored and interrogated both molecular (principally quantitative polymerase chain reaction [qPCR]) and culture-based tools for FIO monitoring under the European Bathing Water Directive. Through detailed analysis of policy implications, regulatory barriers, stakeholder engagement, and the needs of the end-user, the WG identified a series of key concerns that require critical appraisal before a potential shift from culture-based approaches to the employment of molecular biological methods for bathing water regulation could be justified.

There is growing understanding that the environment plays an important role both in the transmission of antibiotic resistant pathogens and in their evolution. Accordingly, researchers and stakeholders world-wide seek to further explore the mechanisms and drivers involved, quantify risks and identify suitable interventions. There is a clear value in establishing research needs and coordinating efforts within and across nations in order to best tackle this global challenge. At an international workshop in late September 2017, scientists from 14 countries with expertise on the environmental dimensions of antibiotic resistance gathered to define critical knowledge gaps. Four key areas were identified where research is urgently needed: 1) the relative contributions of different sources of antibiotics and antibiotic resistant bacteria into the environment; 2) the role of the environment, and particularly anthropogenic inputs, in the evolution of resistance; 3) the overall human and animal health impacts caused by exposure to environmental resistant bacteria; and 4) the efficacy and feasibility of different technological, social, economic and behavioral interventions to mitigate environmental antibiotic resistance.1. ; The workshop was organized and supported by the Joint Programming Initiative on Antimicrobial Resistance (JPIAMR), the Swedish Research Council (SRC) and the Centre for Antibiotic Resistance Research at University of Gothenburg, Sweden (CARe). This project received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement JPI-EC-AMR No 681055. Individual member states of the JPIAMR also covered travel costs for participants. ; Sí