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Geographic and demographic transmission patterns of the 2009 A/H1N1 influenza pandemic in the United States

dc.creatorKissler, Stephen Michael
dc.date.accessioned2018-11-24T23:21:17Z
dc.date.available2018-03-07T09:15:32Z
dc.date.available2018-11-24T23:21:17Z
dc.date.issued2018-05-19
dc.identifierhttps://www.repository.cam.ac.uk/handle/1810/273772
dc.identifier.urihttp://repository.aust.edu.ng/xmlui/handle/123456789/3713
dc.description.abstractThis thesis describes how transmission of the 2009 A/H1N1 influenza pandemic in the United States varied geographically, with emphasis on population distribution and age structure. This is made possible by the availability of medical claims records maintained in the private sector that capture the weekly incidence of influenza-like illness in 834 US cities. First, a probabilistic method is developed to infer each city's outbreak onset time. This reveals a clear wave-like pattern of transmission originating in the south-eastern US. Then, a mechanistic mathematical model is constructed to describe the between-city transmission of the epidemic. A model selection procedure reveals that transmission to a city is modulated by its population size, surrounding population density, and possibly by students mixing in schools. Geographic variation in transmissibility is explored further by nesting a latent Gaussian process within the mechanistic transmission model, revealing a possible region of elevated transmissibility in the south-eastern US. Then, using the mechanistic model and a probabilistic back-tracing procedure, the geographic introduction sites (the `transmission hubs') of the outbreak are identified. The transmission hubs of the 2009 pandemic were generally mid-sized cities, contrasting with the conventional perspective that major outbreaks should start in large population centres with high international connectivity. Transmission is traced forward from these hubs to identify `basins of infection', or regions where outbreaks can be attributed with high probability to a particular hub. The city-level influenza data is also separated into 12 age categories. Techniques adapted from signal processing reveal that school-aged children may have been key drivers of the epidemic. Finally, to provide a point of comparison, the procedures described above are applied to the 2003-04 and 2007-08 seasonal influenza outbreaks. Since the 2007-08 outbreak featured three antigenically distinct strains of influenza, it is possible to identify which antigenic strains may have been responsible for infecting each transmission hub. These strains are identified using a probabilistic model that is joined with the geographic transmission model, providing a link between population dynamics and molecular surveillance.
dc.languageen
dc.publisherUniversity of Cambridge
dc.publisherApplied Mathematics and Theoretical Physics
dc.publisherKing's
dc.rightsNo Creative Commons licence (All rights reserved)
dc.subjectpandemic
dc.subjectinfluenza
dc.subjectH1N1
dc.subjectmetapopulation
dc.subjectgeographic
dc.subjectdemographic
dc.subjecttransmission
dc.subject2009
dc.subjectA/H1N1
dc.subjectUnited States
dc.subjecttransfer entropy
dc.subjecttransmission hubs
dc.subjectinfluenza-like illness
dc.subjectphylogeograhpy
dc.subjectage
dc.subjectgravity model
dc.subjectsymbolic transfer entropy
dc.subjectgaussian process
dc.subjectbreakpoint
dc.subjectZIP
dc.titleGeographic and demographic transmission patterns of the 2009 A/H1N1 influenza pandemic in the United States
dc.typeThesis


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