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Estimating the Location and Spatial Extent of a Covert Anthrax Release

By Judith Legrand, Joseph R. Egan, Ian M. Hall, Simon Cauchemez, Steve Leach and Neil M. Ferguson


Rapidly identifying the features of a covert release of an agent such as anthrax could help to inform the planning of public health mitigation strategies. Previous studies have sought to estimate the time and size of a bioterror attack based on the symptomatic onset dates of early cases. We extend the scope of these methods by proposing a method for characterizing the time, strength, and also the location of an aerosolized pathogen release. A back-calculation method is developed allowing the characterization of the release based on the data on the first few observed cases of the subsequent outbreak, meteorological data, population densities, and data on population travel patterns. We evaluate this method on small simulated anthrax outbreaks (about 25–35 cases) and show that it could date and localize a release after a few cases have been observed, although misspecifications of the spore dispersion model, or the within-host dynamics model, on which the method relies can bias the estimates. Our method could also provide an estimate of the outbreak's geographical extent and, as a consequence, could help to identify populations at risk and, therefore, requiring prophylactic treatment. Our analysis demonstrates that while estimates based on the first ten or 15 observed cases were more accurate and less sensitive to model misspecifications than those based on five cases, overall mortality is minimized by targeting prophylactic treatment early on the basis of estimates made using data on the first five cases. The method we propose could provide early estimates of the time, strength, and location of an aerosolized anthrax release and the geographical extent of the subsequent outbreak. In addition, estimates of release features could be used to parameterize more detailed models allowing the simulation of control strategies and intervention logistics

Topics: Research Article
Publisher: Public Library of Science
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Provided by: PubMed Central
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    1. (2006). A Bayesian method for characterizing distributed micro-releases: I. The single-source case for non-contagious diseases. Sandia National Laboratories.
    2. (2007). A Bayesian method for characterizing distributed micro-releases: II. Inference under model uncertainty with short time series data. Sandia National Laboratories.
    3. (2002). Anthrax as a biological weapon, 2002: updated recommendations for management.
    4. (1999). Anthrax as a biological weapon: medical and public health management. Working Group on Civilian Biodefense.
    5. (1986). Atmospheric chemistry and physics of air pollution.
    6. (2005). Degradation of biological weapons agents in the environment: implications for terrorism response.
    7. (2003). Emergency response to an anthrax attack.
    8. (2008). Estimating the impact of school closure on influenza transmission from Sentinel data.
    9. (2004). Estimating time and size of bioterror attack.
    10. (1996). Markov Chain Monte Carlo in Practice.
    11. (2008). Modeling the Incubation Period of Inhalational Anthrax.
    12. (2003). Modeling the optimum duration of antibiotic prophylaxis in an anthrax outbreak.
    13. (2005). Modelling the incubation period of anthrax.
    14. (2000). On Profile Likelihood.
    15. (2004). Public health vaccination policies for containing an anthrax outbreak.
    16. (2003). Statistical Models and Bioterrorism: Application to the US Anthrax Outbreak.
    17. (2006). Sverdlovsk revisited: modeling human inhalation anthrax.
    18. (2007). The Bayesian aerosol release detector: An algorithm for detecting and characterizing outbreaks caused by an atmospheric release of Bacillus anthracis.
    19. (2005). The Profile Sampler.

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