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Determinants and dynamics of viral host jumps

Posted on:2008-11-20Degree:Ph.DType:Dissertation
University:Princeton UniversityCandidate:Pulliam, Juliet Rachel CrowderFull Text:PDF
GTID:1443390005969851Subject:Biology
Abstract/Summary:
Viral transmission between host species can harm public health, conservation efforts, and the global economy. I examine the determinants and dynamics of viral host jumps by identifying three steps required for viral emergence in a novel host species: encounter (contact between infectious virions and a potential new host species), infection (replication within an individual of a novel host species), and propagation (transmission between individuals of a novel host species). I first lay out a general framework for addressing the interaction of ecology and molecular biology that determines whether a host jump will occur. I then focus in turn on the determinants of infection once encounter has occurred and the dynamics of propagation following infection. I analyze the effect of three specific viral characteristics (site of replication, genome segmentation, and genomic material) on the ability of livestock viruses to infect human hosts. I find that (1) the ability to complete virion replication in the cytoplasm without nuclear entry facilitates viral host jumps, (2) genome segmentation has a non-significant but consistently positive effect on host-jump ability, and (3) having an RNA genome may facilitate host jumps though the effect is equivocal in the dataset used.; I next address the dynamics of propagation within a novel host species. I describe a general phenomenon, epidemic enhancement, whereby repeated viral introduction into a novel host population can produce longer and larger epidemics than observed upon initial introduction. Finally, I show that epidemic enhancement drove Nipah virus emergence in domestic pig populations in Malaysia, which ultimately led to widespread human infection throughout the country.; Overall, I have demonstrated that general principles and mechanisms do underlie cross-species viral transmission. As we continue to unravel the determinants and dynamics of viral host jumps, we will improve our ability to predict, prepare for, and respond to future threats.
Keywords/Search Tags:Host, Viral, Dynamics, Determinants
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