An ongoing, continually spreading, outbreak of African swine fever (ASF), following its identification in Georgia in 2007, has resulted in 17 European and 12 Asian countries reporting cases by April ...2020, with cases occurring in both wild boar and domestic pigs. Curtailing further spread of ASF requires understanding of the transmission pathways of the disease. ASF is self‐sustaining in the wild boar population, and they have been implicated as one of the main drivers of transmission within Europe. We developed a spatially explicit model to estimate the risk of infection with ASF in wild boar and pigs due to natural movement of wild boar that is applicable across the whole of Europe. We demonstrate the model by using it to predict the probability that early cases of ASF in Poland were caused by wild boar dispersion. The risk of infection in 2015 is computed due to wild boar cases in Poland in 2014, compared against reported cases in 2015, and then the procedure is repeated for 2015–2016. We find that long‐ and medium‐distance spread of ASF (i.e. >30 km) is unlikely to have occurred due to wild boar dispersal, due in part to the generally short distances wild boar will travel (<20 km on average). We also predict the relative success of different control strategies in 2015, if they were implemented in 2014. Results suggest that hunting of wild boar reduces the number of new cases, but a larger region is at risk of ASF compared with no control measure. Alternatively, introducing wild boar‐proof fencing reduces the size of the region at risk in 2015, but not the total number of cases. Overall, our model suggests wild boar movement is only responsible for local transmission of disease; thus, other pathways are more dominant in medium‐ and long‐distance spread of the disease.
Bat-borne viruses have been linked to a number of zoonotic diseases; in 2014 there have been human cases of Nipah virus (NiV) in Bangladesh and Ebola virus in West and Central Africa. Here we ...describe a model designed to provide initial quantitative predictions of the risk of entry of such viruses to European Union (EU) Member States (MSs) through four routes: human travel, legal trade (e.g. fruit and animal products), live animal movements and illegal importation of bushmeat. The model utilises available datasets to assess the movement via these routes between individual countries of the world and EU MSs. These data are combined with virus specific data to assess the relative risk of entry between EU MSs. As a case study, the model was parameterised for NiV. Scenario analyses showed that the selection of exporting countries with NiV and potentially contaminated trade products were essential to the accuracy of all model outputs. Uncertainty analyses of other model parameters identified that the model expected number of years to an introduction event within the EU was highly susceptible to the prevalence of NiV in bats. The relative rankings of the MSs and routes, however, were more robust. The UK, the Netherlands and Germany were consistently the most likely points of entry and the ranking of most MSs varied by no more than three places (maximum variation five places). Legal trade was consistently the most likely route of entry, only falling below human travel when the estimate of the prevalence of NiV in bats was particularly low. Any model-based calculation is dependent on the data available to feed into the model and there are distinct gaps in our knowledge, particularly in regard to various pathogen/virus as well as host/bat characteristics. However, the strengths of this model lie in the provision of relative comparisons of risk among routes and MSs. The potential for expansion of the model to include other routes and viruses and the possibility of rapid parameterisation demonstrates its potential for use in an outbreak situation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Vector borne diseases are a continuing global threat to both human and animal health. The ability of vectors such as mosquitos to cover large distances and cross country borders undetected provide an ...ever-present threat of pathogen spread. Many diseases can infect multiple vector species, such that even if the climate is not hospitable for an invasive species, indigenous species may be susceptible and capable of transmission such that one incursion event could lead to disease establishment in these species. Here we present a consensus modelling methodology to estimate the habitat suitability for presence of mosquito species in the UK deemed competent for Rift Valley fever virus (RVF) and demonstrate its application in an assessment of the relative risk of establishment of RVF virus in the UK livestock population. The consensus model utilises observed UK mosquito surveillance data, along with climatic and geographic prediction variables, to inform six independent species distribution models; the results of which are combined to produce a single prediction map. As a livestock host is needed to transmit RVF, we then combine the consensus model output with existing maps of sheep and cattle density to predict the areas of the UK where disease is most likely to establish in local mosquito populations. The model results suggest areas of high suitability for RVF competent mosquito species across the length and breadth of the UK. Notable areas of high suitability were the South West of England and coastal areas of Wales, the latter of which was subsequently predicted to be at higher risk for establishment of RVF due to higher livestock densities. This study demonstrates the applicability of outputs of species distribution models to help predict hot-spots for risk of disease establishment. While there is still uncertainty associated with the outputs we believe that the predictions are an improvement on just using the raw presence points from a database alone. The outputs can also be used as part of a multidisciplinary approach to inform risk based disease surveillance activities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Risk assessment is an essential tool used in the control of disease outbreaks. Without it, key risk pathways might not be identified, resulting in potential spread of disease. The devastating effects ...of disease spread can ripple through society, affecting the economy and trade and having considerable impact on animal health and potentially human health. The World Organisation for Animal Health (WOAH, founded as OIE) has highlighted that risk analysis, which includes risk assessment, is not consistently used across all Members, with some low-income countries making policy decisions without prior risk assessment. The failure of some Members to rely on risk assessment could be caused by a lack of staff and risk assessment-related training, poor funding in the animal health sector, and lack of understanding regarding the use and application of risk analysis. However, to complete effective risk assessment, high-quality data must be collected, and other factors such as geographical conditions, use (or not) of technology, and varying production systems all influence the ability to collect these data. Demographic and population-level data can be collected during peacetime in the form of surveillance schemes and national reports. Having these data before an outbreak occurs better equips a country for controlling or preventing disease outbreaks. In order for all WOAH Members to meet risk analysis requirements, an international effort must be made for cross-working and the development of collaborative schemes. Technology can play an important role in the development of risk analysis, and low-income countries must not be left behind in the efforts to protect animal and human populations from disease.
Aims
In 2015, colistin‐resistant Escherichia coli and Salmonella with the mcr‐1 gene were isolated from a pig farm in Great Britain. Pigs were subsequently monitored over a ~20‐month period for the ...occurrence of mcr‐1‐mediated colistin resistance and the risk of mcr‐1 E. coli entering the food chain was assessed.
Methods and Results
Pig faeces and slurry were cultured for colistin‐resistant E. coli and Salmonella, tested for the mcr‐1 gene by PCR and selected isolates were further analysed. Seventy‐eight per cent of faecal samples (n = 275) from pigs yielded mcr‐1 E. coli after selective culture, but in positive samples only 0·2–1·3% of the total E. coli carried mcr‐1. Twenty months after the initial sampling, faecal samples (n = 59) were negative for E. coli carrying mcr‐1.
Conclusions
The risk to public health from porcine E. coli carrying mcr‐1 was assessed as very low. Twenty months after cessation of colistin use, E. coli carrying mcr‐1 was not detected in pig faeces on a farm where it was previously present.
Significance and Impact of the Study
The results suggest that cessation of colistin use may help over time to reduce or possibly eliminate mcr‐1 E. coli on pig farms where it occurs.
A model for the transmission of Salmonella between finisher pigs during transport to the abattoir and subsequent lairage has been developed, including novel factors such as environmental ...contamination and the effect of stress, and is designed to be adaptable for any EU Member State (MS). The model forms part of a generic farm‐to‐consumption model for Salmonella in pigs, designed to model potentially important risk factors and assess the effectiveness of interventions. In this article, we discuss the parameterization of the model for two case study MSs. For both MSs, the model predicted an increase in the average MS‐level prevalence of Salmonella‐positive pigs during both transport and lairage, accounting for a large amount of the variation between reported on‐farm prevalence and reported lymph‐node prevalence at the slaughterhouse. Sensitivity analysis suggested that stress is the most important factor during transport, while a number of factors, including environmental contamination and the dose‐response parameters, are important during lairage. There was wide variation in the model‐predicted change in prevalence in individual batches; while the majority of batches (80–90%) had no increase, in some batches the increase in prevalence was over 70% and in some cases infection was introduced into previously uninfected batches of pigs. Thus, the model suggests that while the transport and lairage stages of the farm‐to‐consumption exposure pathway are unlikely to be responsible for a large increase in average prevalence at the MS level, they can have a large effect on prevalence at an individual‐batch level.
Pork and pork products are a major source of human salmonellosis in the United Kingdom (UK). Despite a number of surveillance programmes, the prevalence of Salmonella in the UK slaughter pig ...population remains over 20%. Here, we present the results of a Cost-Benefit Analysis comparing five on-farm control strategies (where the cost is the cost of implementation and the benefits are the financial savings for both the human health and pig industries). The interventions considered were: wet feed, organic acids in feed, vaccination, enhanced cleaning and disinfection and movement of outdoor breeding units. The data originate from published papers and recent UK studies. The effectiveness was assessed by adapting a previous risk assessment, originally developed for the European Food Safety Authority. Using this method, none of the intervention strategies produced a net cost-benefit. Our results suggest that the cost of implementation outweighed the savings for all interventions, even if the effectiveness could be improved. Therefore, to achieve a net cost-benefit it is essential to reduce the cost of interventions. Analyses concluded that large cost reductions (up to 96%) would be required. Use of organic acids required the smallest reduction in cost (22.7%) to achieve a net cost benefit. Uncertainty analysis suggested that a small net gain might be possible, for some of the intervention measures. But this would imply that the model greatly underestimated some key parameters, which was considered unlikely. Areas of key uncertainty were identified as the under-reporting factor (i.e. the proportion of community cases of Salmonella) and the source attribution factor (i.e. the proportion of human Salmonella cases attributable to pork products).
Abstract Background Tibial plateau fractures account for approximately 1% of all fractures. They usually occur after a direct high-energy trauma. Despite adequate treatment, these fractures can ...result in malalignment and secondary osteoarthritis (OA). Research concerning long-term functional outcome is limited. The primary aim of this study was to evaluate mid- to long-term functional outcome of surgically treated tibial plateau fractures. The secondary aim was to investigate whether radiological characteristics of OA one year after surgery are predictive of functional outcome at follow-up. Methods All consecutive patients with fractures of the proximal tibia, which were surgically treated in our level-2 trauma centre between 2004 and 2010, were included in this study. Initial trauma radiographs were analysed for fracture classification, using both the Schatzker and AO/OTA classification systems, by three different raters. Immediate postoperative and 1-year postoperative radiographs were analysed for osteoarthritis by an experienced radiologist, using the Kellgren and Lawrence scale. Functional outcome of the included patients was measured using the Dutch version of the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire. Results Seventy one patients out of a group of 96 included patients completed the survey. Median KOOS scores are 89.8% for pain, 91.1% for ‘other symptoms’, 89.7% for daily function, 72.5% for sports and recreation and 75.0% for quality of life. Median KOOS overall score is 82.99%. We did not find a correlation between the KOOS scores and the absolute age for any of the subscales. There was no significant relationship between radiological characteristics of osteoarthritis and functional outcome. Conclusions This is the first study to describe mid- to long-term functional outcome after ORIF for all types of tibial plateau fractures, with the use of the KOOS. Patients should be informed about the likelihood of lower functional outcome in the long-term. This study shows that radiological characteristics of osteoarthritis are not related with lower functional outcomes in the mid- to long-term.
African swine fever (ASF) is currently spreading westwards throughout Europe and eastwards into China, with cases occurring in both wild boar and domestic pigs. A generic risk assessment framework is ...used to determine the probability of first infection with ASF virus (ASFV) at a fine spatial scale across European Union Member States. The framework aims to assist risk managers across Europe with their ASF surveillance and intervention activities. Performing the risk assessment at a fine spatial scale allows for hot-spot surveillance, which can aid risk managers by directing surveillance or intervention resources at those areas or pathways deemed most at risk, and hence enables prioritization of limited resources. We use 2018 cases of ASF to estimate prevalence of the disease in both wild boar and pig populations and compute the risk of initial infection for 2019 at a 100 km
cell resolution via three potential pathways: legal trade in live pigs, natural movement of wild boar, and legal trade in pig meat products. We consider the number of pigs, boar and amount of pig meat entering our area of interest, the prevalence of the disease in the origin country, the probability of exposure of susceptible pigs or boar in the area of interest to introduced infected pigs, boar, or meat from an infected pig, and the probability of transmission to susceptible animals. We provide maps across Europe indicating regions at highest risk of initial infection. Results indicate that the risk of ASF in 2019 was predominantly focused on those regions which already had numerous cases in 2018 (Poland, Lithuania, Hungary, Romania, and Latvia). The riskiest pathway for ASFV transmission to pigs was the movement of wild boar for Eastern European countries and legal trade of pigs for Western European countries. New infections are more likely to occur in wild boar rather than pigs, for both the pig meat and wild boar movement pathways. Our results provide an opportunity to focus surveillance activities and thus increase our ability to detect ASF introductions earlier, a necessary requirement if we are to successfully control the spread of this devastating disease for the pig industry.
•We describe a quantitative approach to develop risk scores for bovine tuberculosis.•It's a unified scheme for England and Wales for farmers to use when trading cattle.•Risk scores ranging from 1 to ...5 were estimated for each cattle farm.•Using the risk score has the potential to reduce infected cattle movements.•Information underpinning the scheme needs to be accurate and up to date.
Identifying and ranking cattle herds with a higher risk of being or becoming infected on known risk factors can help target farm biosecurity, surveillance schemes and reduce spread through animal trading. This paper describes a quantitative approach to develop risk scores, based on the probability of infection in a herd with bovine tuberculosis (bTB), to be used in a risk-based trading (RBT) scheme in England and Wales. To produce a practical scoring system the risk factors included need to be simple and quick to understand, sufficiently informative and derived from centralised national databases to enable verification and assess compliance. A logistic regression identified herd history of bTB, local bTB prevalence, herd size and movements of animals onto farms in batches from high risk areas as being significantly associated with the probability of bTB infection on farm. Risk factors were assigned points using the estimated odds ratios to weight them. The farm risk score was defined as the sum of these individual points yielding a range from 1 to 5 and was calculated for each cattle farm that was trading animals in England and Wales at the start of a year. Within 12 months, of those farms tested, 30.3% of score 5 farms had a breakdown (sensitivity). Of farms scoring 1–4 only 5.4% incurred a breakdown (1-specificity). The use of this risk scoring system within RBT has the potential to reduce infected cattle movements; however, there are cost implications in ensuring that the information underpinning any system is accurate and up to date.
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