201 research outputs found

    Survey of wood mice (Apodemus sylvaticus) on the Isle of Rum

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    There is currently little knowledge of the wood mouse (Apodemus sylvaticus) population on the Isle of Rum (Inner Hebrides, Scotland). Informal monitoring suggests that the mice on the island are larger than their mainland conspecifics, and also that wood mice on Rum are found living at higher altitudes than on the mainland. In 2009, SNH staff on Rum invited the Department of Life Sciences at Anglia Ruskin University to carry out a pilot survey of the wood mice on Rum, using live trapping to determine distribution and abundance. An important objective of this survey was to provide information about the likely consequences for the Rum wood mouse population of proposed rat control measures on the island. The main findings of this survey were as follows: Wood mice were found at all sites (n= 8) surveyed on Rum, from just above sea level to above 450m in the Manx shearwater (Puffinus puffinus) nesting colonies. Wood mice were most abundant in areas of mature mixed woodland, but were also found in other habitats such as coniferous woodland and Molinia-dominated wet grasslands, and in areas where there has been no permanent human habitation for several decades. Trap damage sustained during this survey indicates possible brown rat (Rattus norvegicus) predation of wood mice on Rum. The implications of this finding, in relation to proposed future rat control on Rum, are discussed. Morphological data obtained during this study show that the wood mice on Rum are particularly large (a number of adult mice captured, of both sexes, had body weights of >30g). There was a significant difference in size between mice found around human habitation at low altitudes, and the (larger) mice living at high altitudes on Rum in the shearwater colonies. Recommendations for further research into the wood mice on Rum are outlined

    Understanding the Role of Duration of Vaccine Protection with MenAfriVac: Simulating Alternative Vaccination Strategies.

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    We previously developed a transmission dynamic model of Neisseria meningitidis serogroup A (NmA) with the aim of forecasting the relative benefits of different immunisation strategies with MenAfriVac. Our findings suggested that the most effective strategy in maintaining disease control was the introduction of MenAfriVac into the Expanded Programme on Immunisation (EPI). This strategy is currently being followed by the countries of the meningitis belt. Since then, the persistence of vaccine-induced antibodies has been further studied and new data suggest that immune response is influenced by the age at vaccination. Here, we aim to investigate the influence of both the duration and age-specificity of vaccine-induced protection on our model predictions and explore how the optimal vaccination strategy may change in the long-term. We adapted our previous model and considered plausible alternative immunization strategies, including the addition of a booster dose to the current schedule, as well as the routine vaccination of school-aged children for a range of different assumptions regarding the duration of protection. To allow for a comparison between the different strategies, we use several metrics, including the median age of infection, the number of people needed to vaccinate (NNV) to prevent one case, the age distribution of cases for each strategy, as well as the time it takes for the number of cases to start increasing after the honeymoon period (resurgence). None of the strategies explored in this work is superior in all respects. This is especially true when vaccine-induced protection is the same regardless of the age at vaccination. Uncertainty in the duration of protection is important. For duration of protection lasting for an average of 18 years or longer, the model predicts elimination of NmA cases. Assuming that vaccine protection is more durable for individuals vaccinated after the age of 5 years, routine immunization of older children would be more efficient in reducing disease incidence and would also result in a fewer number of doses necessary to prevent one case. Assuming that elimination does not occur, adding a booster dose is likely to prevent most cases but the caveat will be a more costly intervention. These results can be used to understand important sources of uncertainty around MenAfriVac and support decisions by policymakers

    The influence of heat on biological activity and concentration of oleocanthal - a natural anti-inflammatory agent

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    Background &ndash; The olive oil phenolic, oleocanthal is a natural non-steroidal anti-inflammatory compound that irritates the oropharynx in a dose-dependent manner. It has been proposed that the biological activity of oleocanthal is partially responsible for the beneficial health effects of the Mediterranean diet. Virgin olive oil containing oleocanthal is often added as an ingredient in a number of cooked dishes and therefore it is of great importance to understand how best to preserve the putative health promoting benefits of this compound, as olive oil phenolics aresubject to heat degradation.Objective &ndash; To investigate if oleocanthal is thermally degraded or its biological activity reduced during cooking.Design &ndash; One extra virgin olive oil containing 54mg/kg oleocanthal was heated at varying temperatures (100&deg;C, 170&deg;C and 240&deg;C) for set time periods (0, 1, 5, 20, 60, 90 min). Oleocanthal concentrations were quantified using HPLC and its biological activity determined with a taste bioassay measuring the intensity of throat irritation.Outcomes &ndash; Results demonstrated that oleocanthal was heat stable compared with other olive oil phenolics, with a maximum loss of 16% as determined by HPLC analysis. In contrast, there was a significant decrease of up to 38% (p&lt;0.05) in the biological activity of oleocanthal as determined by the taste bioassay.Conclusions &ndash; Minimal degradation of oleocanthal concentration was observed upon heating however a significant decrease in the biological activity of this compound was noted with extended heating time. This has important implications for health in that, consumers may be unable to reap all of the putative health benefits associated with oleocanthal when adding virgin olive oil as an ingredient to dishes requiring prolonged heat treatment.<br /

    Risk factors and variations in detection of new bovine tuberculosis breakdowns via slaughterhouse surveillance in Great Britain.

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    Slaughterhouse surveillance through post-mortem meat inspection provides an important mechanism for detecting bovine tuberculosis (bTB) infections in cattle herds in Great Britain (GB), complementary to the live animal skin test based programme. We explore patterns in the numbers of herd breakdowns detected through slaughterhouse surveillance and develop a Bayesian hierarchical regression model to assess the associations of animal-level factors with the odds of an infected animal being detected in the slaughterhouse, allowing us to highlight slaughterhouses that show atypical patterns of detection. The analyses demonstrate that the numbers and proportions of breakdowns detected in slaughterhouses increased in GB over the period of study (1998-2013). The odds of an animal being a slaughterhouse case was strongly associated with the region of the country that the animal spent most of its life, with animals living in high-frequency testing areas of England having on average 21 times the odds of detection compared to animals living in Scotland. There was also a strong effect of age, with animals slaughtered at > 60 months of age having 5.3 times the odds of detection compared to animals slaughtered between 0-18 months of age. Smaller effects were observed for cattle having spent time on farms with a history of bTB, quarter of the year that the animal was slaughtered, movement and test history. Over-and-above these risks, the odds of detection increased by a factor of 1.1 for each year of the study. After adjustment for these variables, there were additional variations in risk between slaughterhouses and breed. Our framework has been adopted into the routine annual surveillance reporting carried out by the Animal Plant Health Agency and may be used to target more detailed investigation of meat inspection practices.Defra Project SE3133. (Department of Environment and Rural Affairs, UK Government

    Chemistry and health of olive oil phenolics

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    The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular disease, and certain types of cancer. The apparent health benefits have been partially attributed to the dietary consumption of virgin olive oil by Mediterranean populations. Most recent interest has focused on the biologically active phenolic compounds naturally present in virgin olive oils. Studies (human, animal, in vivo and in vitro) have shown that olive oil phenolics have positive effects on certain physiological parameters, such as plasma lipoproteins, oxidative damage, inflammatory markers, platelet and cellular function, and antimicrobial activity. Presumably, regular dietary consumption of virgin olive oil containing phenolic compounds manifests in health benefits associated with a Mediterranean diet. This paper summarizes current knowledge on the physiological effects of olive oil phenolics. Moreover, a number of factors have the ability to affect phenolic concentrations in virgin olive oil, so it is of great importance to understand these factors in order to preserve the essential health promoting benefits of olive oil phenolic compounds.<br /

    Efficient Bayesian model choice for partially observed processes: with application to an experimental transmission study of an infectious disease

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    Infectious diseases such as avian influenza pose a global threat to human health. Mathematical and statistical models can provide key insights into the mechanisms that underlie the spread and persistence of infectious diseases, though their utility is linked to the ability to adequately calibrate these models to observed data. Performing robust inference for these systems is challenging. The fact that the underlying models exhibit complex non-linear dynamics, coupled with practical constraints to observing key epidemiological events such as transmission, requires the use of inference techniques that are able to numerically integrate over multiple hidden states and/or infer missing information. Simulation-based inference techniques such as Approximate Bayesian Computation (ABC) have shown great promise in this area, since they rely on the development of suitable simulation models, which are often easier to code and generalise than routines that require evaluations of an intractable likelihood function. In this manuscript we make some contributions towards improving the efficiency of ABC-based particle Markov chain Monte Carlo methods, and show the utility of these approaches for performing both model inference and model comparison in a Bayesian framework. We illustrate these approaches on both simulated data, as well as real data from an experimental transmission study of highly pathogenic avian influenza in genetically modi fied chickens.This work was supported by the Biotechnology and Biological Sciences Research Council (grants BB/G00479X/1, BBS/B/00239, and BBS/B/00301) and by the Cambridge Infectious Diseases Consortium Department for Environment, Food and Rural Affairs-Higher Education Funding Council for England (grant VT0105). AJKC was supported by BBSRC grant BB/I024550/1

    The intractable challenge of evaluating cattle vaccination as a control for bovine tuberculosis

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    Vaccination of cattle against bovine Tuberculosis (bTB) has been a long-term policy objective for countries where disease continues to persist despite costly test-and-slaughter programs. The potential use of vaccination within the European Union has been linked to a need for field evaluation of any prospective vaccine and the impact of vaccination on the rate of transmission of bTB. We calculate that estimation of the direct protection of BCG could be achieved with 100 herds, but over 500 herds would be necessary to demonstrate an economic benefit for farmers whose costs are dominated by testing and associated herd restrictions. However, the low and variable attack rate in GB herds means field trials are unlikely to be able to discern any impact of vaccination on transmission. In contrast, experimental natural transmission studies could provide robust evaluation of both the efficacy and mode of action of vaccination using as few as 200 animals

    Age-dependent patterns of bovine tuberculosis in cattle.

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    Bovine tuberculosis (BTB) is an important livestock disease, seriously impacting cattle industries in both industrialised and pre-industrialised countries. Like TB in other mammals, infection is life long and, if undiagnosed, may progress to disease years after exposure. The risk of disease in humans is highly age-dependent, however in cattle, age-dependent risks have yet to be quantified, largely due to insufficient data and limited diagnostics. Here, we estimate age-specific reactor rates in Great Britain by combining herd-level testing data with spatial movement data from the Cattle Tracing System (CTS). Using a catalytic model, we find strong age dependencies in infection risk and that the probability of detecting infection increases with age. Between 2004 and 2009, infection incidence in cattle fluctuated around 1%. Age-specific incidence increased monotonically until 24-36 months, with cattle aged between 12 and 36 months experiencing the highest rates of infection. Beef and dairy cattle under 24 months experienced similar infection risks, however major differences occurred in older ages. The average reproductive number in cattle was greater than 1 for the years 2004-2009. These methods reveal a consistent pattern of BTB rates with age, across different population structures and testing patterns. The results provide practical insights into BTB epidemiology and control, suggesting that targeting a mass control programme at cattle between 12 and 36 months could be beneficial.EBP is funded by an Engineering and Physical Sciences Research Council (EPSRC) fellowship. JLNW is supported by the Alborada Trust and the RAPIDD program of the Science & Technology Directorate, U.S. Department of Homeland Security, and the Fogarty International Center, U.S. National Institutes of Health. AJKC is supported by Defra grant no. SE-3127. TJM is supported by the BBSRC. We thank Steve Holdship and Rose Nicholson at Defra the AHVLA team for providing access to the CTS and VetNet
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