1,721,024 research outputs found
Visualization and Analysis of the Danish 2006 Highly Pathogenic Avian Influenza Virus H5N1 Wild Bird Surveillance Data by a Prototype Avian Influenza BioPortal
Get PDFInfection with highly pathogenic avian influenza virus H5N1 occurred for the first time in Denmark in 2006 during the last part of the European epidemic that mainly affected migrating wild birds. The total number of Danish wild bird cases was 45, of which only one was found through active surveillance using fecal sampling from resting areas for migrating species, whereas passive surveillance of dead wild birds provided 44 cases. One backyard, mixed poultry flock also became infected late in the epidemic. This study describes the spatial and temporal distribution of cases, initially characterized by a spatial-temporal cluster of affected tufted ducks that led to further spread to other wild bird species in the vicinity. The surveillance data also indicate an apparent die-off of the regional epidemic. As a tool in visualizing the spatial and temporal development of the epidemic, a prototype avian influenza (AI) BioPortal was used to provide online web-based access to the data. The AI BioPortal tools include mapping, graphing, phylogenetic tree construction, playback scenarios, and visualization of results of temporal-spatial analyses. Several of the features of this surveillance system compare favorably to the design of existing national and international surveillance information systems, and the AI BioPortal may become a useful tool for disease surveillance and for decision support in the event of future AI epidemics, both at national and international levels.Fil: Willeberg, Preben. University of California; Estados UnidosFil: Perez, Andres Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. University of California; Estados UnidosFil: Thurmond, Mark. University of California; Estados UnidosFil: Ascher, Mike. University of California; Estados UnidosFil: Carpenter, Tim. University of California; Estados UnidosFil: AlKhamis, Mohammad. University of California; Estados Unido
A review of FMD emergency vaccination strategies and their implementation in contingency planning
Get PDFA simple decision tool to help optimize the control strategy 2 weeks into a Danish FMD epidemic
Get PDFA literature review of Foot-and-Mouth Disease emergency vaccination strategies and their implementation in contingency planning
Get PDFThere is no single FMD eradication strategy that is perfect or even appropriate for all circumstances. The emphasis given to various control measures in devising FMD control and eradication strategies will depend on epidemiological factors, livestock husbandry systems, community acceptance and the likely costs. The strategy chosen is likely to be a combination of some appropriate approaches and will likely have to be adapted to the development of the epidemic over time.These conditions make it difficult to choose an optimal strategy early on in the epidemic, and therefore contingency plans can by the nature of the situation not be very specific about this issue. In addition different countries have different political and social experiences, traditions and needs, which can be challenged during an epidemic by political, economic or public opinions. Nevertheless, there has been a considerable international movement during the past decade towards preparing for the use of emergency vaccination in the case of an FMD epidemic.Various types of decision tools have been developed to assist in making timely and difficult decisions on how to manage FMD outbreaks. Considering the multi-factorial management decisions taking into account all relevant conditions, it is not surprising, that there has been limited practical experience with these tools as documented in the literature.Even simulation models are limited in their capacity to embrace all factors that might influence decisions on the best strategy. It is important to realize that scenarios used for FMD simulation models focusing on alternative control strategies require not only that the control strategy can be specified and modified over time according to the progress achieved, but also that an appropriate type of epidemic is unfolding, since simulations with identical seed value may develop quite differently, according to which herds initially become infected, the animal species, the regional herd density, etc. Depending on the time of detection, speed of spread, human resources available, etc. the epidemic will vary and the choice of an optimal strategy will differ.Taken across all the literature covered by this report there are however a few key points that seem to prevail as far as the potential use of emergency vaccination (EV) for FMD:• Although it is recommended or even required that national contingency plans contain detailed preparations for applying EV, this is not always the situation. The problem is likely due to the many different situations that may develop during an epidemic, which makes it difficult to prescribe certain strategies in advance. Regular simulation exercises with different scenarios can make up for some of these problems.• According to some experts, predictive models should not be used during an epidemic, unless the model has been verified, validated and exercised in advance, and provided up-There is no single FMD eradication strategy that is perfect or even appropriate for all circumstances. The emphasis given to various control measures in devising FMD control and eradication strategies will depend on epidemiological factors, livestock husbandry systems, community acceptance and the likely costs. The strategy chosen is likely to be a combination of some appropriate approaches and will likely have to be adapted to the development of the epidemic over time.These conditions make it difficult to choose an optimal strategy early on in the epidemic, and therefore contingency plans can by the nature of the situation not be very specific about this issue. In addition different countries have different political and social experiences, traditions and needs, which can be challenged during an epidemic by political, economic or public opinions. Nevertheless, there has been a considerable international movement during the past decade towards preparing for the use of emergency vaccination in the case of an FMD epidemic.Various types of decision tools have been developed to assist in making timely and difficult decisions on how to manage FMD outbreaks. Considering the multi-factorial management decisions taking into account all relevant conditions, it is not surprising, that there has been limited practical experience with these tools as documented in the literature.Even simulation models are limited in their capacity to embrace all factors that might influence decisions on the best strategy. It is important to realize that scenarios used for FMD simulation models focusing on alternative control strategies require not only that the control strategy can be specified and modified over time according to the progress achieved, but also that an appropriate type of epidemic is unfolding, since simulations with identical seed value may develop quite differently, according to which herds initially become infected, the animal species, the regional herd density, etc. Depending on the time of detection, speed of spread, human resources available, etc. the epidemic will vary and the choice of an optimal strategy will differ.Taken across all the literature covered by this report there are however a few key points that seem to prevail as far as the potential use of emergency vaccination (EV) for FMD:• Although it is recommended or even required that national contingency plans contain detailed preparations for applying EV, this is not always the situation. The problem is likely due to the many different situations that may develop during an epidemic, which makes it difficult to prescribe certain strategies in advance. Regular simulation exercises with different scenarios can make up for some of these problems.• According to some experts, predictive models should not be used during an epidemic, unless the model has been verified, validated and exercised in advance, and provided up-to-date epidemiological information of sufficient quality and detail is available to feed into the model. Models that mimic the biological behaviour of the epidemic seem to be more useful than purely mathematical models.• Timing is important – most epidemic situations would be tackled initially by stamping-out of affected and in-contact herds, which in some situations may be sufficient to stop the spread; if not, EV should be considered, but if the spread has already been considerable due to late detection, wind-borne spread, long-distance spread by trade, etc., it may be too late to benefit from EV.• Suppressive and protective EV strategies are not in general as cost-efficient as stamping-out strategies, but EV may be considered as a means of protecting against a catastrophic development of the epidemic. EV is resource-demanding, especially when combined with stamping-out (suppressive EV), but protective EV may even be more costly overall, due to long-term trade implications.• EV in ring-zones can be as effective as stamping-out strategies in preventing further spread, if the time needed for immunity to develop is not critical, e.g. if the infection was detected and contained rapidly and if wide-spread infection has been prevented due to effective and rapid stand-still, no risk of wind-borne spread, etc
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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