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Quantitative Methods to Characterize Viral Infection Dynamics Inside Hosts
Quantitative Methods to Characterize Viral Infection Dynamics Inside Hosts
Quantitative Methods to Characterize Viral Infection Dynamics Inside Hosts

상세정보

자료유형  
 학위논문 서양
최종처리일시  
20250211153123
ISBN  
9798346855156
DDC  
574
저자명  
Snedden, Celine Elisa.
서명/저자  
Quantitative Methods to Characterize Viral Infection Dynamics Inside Hosts
발행사항  
[Sl] : University of California, Los Angeles, 2024
발행사항  
Ann Arbor : ProQuest Dissertations & Theses, 2024
형태사항  
283 p
주기사항  
Source: Dissertations Abstracts International, Volume: 86-06, Section: B.
주기사항  
Advisor: Lloyd-Smith, James O.
학위논문주기  
Thesis (Ph.D.)--University of California, Los Angeles, 2024.
초록/해제  
요약The pathogenicity and transmissibility of a virus are strongly governed by spatial patterns of viral growth and spread across the internal tissue landscape of the host individual. These 'within-host dynamics' can differ widely among pathogens, and even among individuals infected with the same pathogen. Epidemiologists and microbiologists have long understood that many factors contribute to this observed heterogeneity, including the dose and route of exposure, host demographic and health factors, the cellular properties of different tissues (e.g., receptor expression), viral sensitivity to within-host abiotic conditions (e.g., temperature, pH), and physical connectivity between tissues (e.g., via blood). However, the relative effects of these governing processes on realized infection patterns inside hosts are difficult to disentangle and remain poorly understood, largely due to sampling constraints and data limitations. For humans, natural exposure events are inherently unobservable, and available data can be biased towards individuals with more severe disease that seek treatment. Animal challenge experiments can control the relevant dimensions, but they either have limited clinical relevance due to crucial physiological differences from humans (e.g., for small animal models), or their small sample sizes cannot support robust statistical inferences under the standard approach of analyzing data only within the study that generated them (e.g., for non-human primate models).Modern, data-driven computational models offer a powerful but underutilized toolkit to overcome these observational and analytical limitations. By using Bayesian statistical approaches to integrate quantitative modeling techniques with experimental data, it is possible to extract underlying patterns and putative mechanisms from limited empirical observations and to enhance these insights by jointly analyzing disparate datasets. In this dissertation, I develop and apply such methods to characterize the effects of exposure route, exposure dose, tissue connectivity, tissue traits, and host demographic factors on within-host SARS-CoV-2 dynamics. These analyses are supported by a large database of 107 studies that I have constructed, which includes 22,183 viral measurements from 721 non-human primates that were experimentally challenged with SARS-CoV-2 by various routes and with various doses.In chapter 1, I address the fundamental question of when (if ever) RT-qPCR measurements of viral RNA load can reliably indicate the presence of infectious virus in a sampled tissue. This work constitutes the largest analysis of this question using in vivo infection data from individuals with known exposure conditions, and it lays crucial groundwork for the application of my customized statistical approach to public health contexts. I demonstrate that total RNA measurements can indeed predict culture positivity with a remarkable 85% accuracy on out-of-sample data as long as predictions also account for other factors, including exposure conditions, host demographics, and assay protocols.In chapter 2, I conduct the first large-scale quantitative analysis of respiratory virus challenge experiments in non-human primates to characterize the relative impacts of exposure route, exposure dose, age, sex, and species on within-host dynamics. I show that exposure route more strongly modulates the probability, onset, peak, and conclusion of SARS-CoV-2 infection across the respiratory and gastrointestinal tracts than exposure dose or demographic factors. I also show that infection patterns following aerosol inhalation are clearly distinct from any other exposure route, including intranasal or combined intranasal/intratracheal inoculation. This work provides the most comprehensive and quantitative evidence to date that exposure conditions shape infection patterns inside hosts, in ways that affect disease risk and shedding potential.In chapter 3, I develop a novel modeling framework that formally investigates how tissue traits (e.g., receptor expression, protease availability) and connectivity structure interact to determine spatiotemporal infection patterns inside hosts, which I fit to the data from nine challenge studies. This model shows that SARS-CoV-2 infection patterns across the respiratory and gastrointestinal tracts are shaped by high rates of within-host viral dissemination. I also show that infections are overall more successful in the nose and throat than in the lung and lower GI, which is consistent with an estimated increase in the local infection rates at the lower ambient temperature of the upper respiratory tract.Together, these chapters demonstrate that meta-analysis of the data from in vivo challenge experiments can overcome the difficulties arising from limited sample sizes in crucial but costly animal models and that they can yield robust insights beyond those attainable from individual studies, all while reducing overall animal use in infectious disease research. This dissertation focuses on characterizing SARS-CoV-2 infections in non-human primates, but the methods developed here can be readily adapted to any other pathogen-host system, and they present generalizable, quantitative approaches to answer questions at the frontier of virology.
일반주제명  
Biology
일반주제명  
Virology
일반주제명  
Ecology
일반주제명  
Biostatistics
키워드  
Bayesian statistics
키워드  
Computational biology
키워드  
Disease ecology
키워드  
Meta-analysis
키워드  
Viral dynamics
기타저자  
University of California, Los Angeles Biology 0123
기본자료저록  
Dissertations Abstracts International. 86-06B.
전자적 위치 및 접속  
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MARC

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■1001  ▼aSnedden,  Celine  Elisa.
■24510▼aQuantitative  Methods  to  Characterize  Viral  Infection  Dynamics  Inside  Hosts
■260    ▼a[Sl]▼bUniversity  of  California,  Los  Angeles▼c2024
■260  1▼aAnn  Arbor▼bProQuest  Dissertations  &  Theses▼c2024
■300    ▼a283  p
■500    ▼aSource:  Dissertations  Abstracts  International,  Volume:  86-06,  Section:  B.
■500    ▼aAdvisor:  Lloyd-Smith,  James  O.
■5021  ▼aThesis  (Ph.D.)--University  of  California,  Los  Angeles,  2024.
■520    ▼aThe  pathogenicity  and  transmissibility  of  a  virus  are  strongly  governed  by  spatial  patterns  of  viral  growth  and  spread  across  the  internal  tissue  landscape  of  the  host  individual.  These  'within-host  dynamics'  can  differ  widely  among  pathogens,  and  even  among  individuals  infected  with  the  same  pathogen.  Epidemiologists  and  microbiologists  have  long  understood  that  many  factors  contribute  to  this  observed  heterogeneity,  including  the  dose  and  route  of  exposure,  host  demographic  and  health  factors,  the  cellular  properties  of  different  tissues  (e.g.,  receptor  expression),  viral  sensitivity  to  within-host  abiotic  conditions  (e.g.,  temperature,  pH),  and  physical  connectivity  between  tissues  (e.g.,  via  blood).  However,  the  relative  effects  of  these  governing  processes  on  realized  infection  patterns  inside  hosts  are  difficult  to  disentangle  and  remain  poorly  understood,  largely  due  to  sampling  constraints  and  data  limitations.  For  humans,  natural  exposure  events  are  inherently  unobservable,  and  available  data  can  be  biased  towards  individuals  with  more  severe  disease  that  seek  treatment.  Animal  challenge  experiments  can  control  the  relevant  dimensions,  but  they  either  have  limited  clinical  relevance  due  to  crucial  physiological  differences  from  humans  (e.g.,  for  small  animal  models),  or  their  small  sample  sizes  cannot  support  robust  statistical  inferences  under  the  standard  approach  of  analyzing  data  only  within  the  study  that  generated  them  (e.g.,  for  non-human  primate  models).Modern,  data-driven  computational  models  offer  a  powerful  but  underutilized  toolkit  to  overcome  these  observational  and  analytical  limitations.  By  using  Bayesian  statistical  approaches  to  integrate  quantitative  modeling  techniques  with  experimental  data,  it  is  possible  to  extract  underlying  patterns  and  putative  mechanisms  from  limited  empirical  observations  and  to  enhance  these  insights  by  jointly  analyzing  disparate  datasets.  In  this  dissertation,  I  develop  and  apply  such  methods  to  characterize  the  effects  of  exposure  route,  exposure  dose,  tissue  connectivity,  tissue  traits,  and  host  demographic  factors  on  within-host  SARS-CoV-2  dynamics.  These  analyses  are  supported  by  a  large  database  of  107  studies  that  I  have  constructed,  which  includes  22,183  viral  measurements  from  721  non-human  primates  that  were  experimentally  challenged  with  SARS-CoV-2  by  various  routes  and  with  various  doses.In  chapter  1,  I  address  the  fundamental  question  of  when  (if  ever)  RT-qPCR  measurements  of  viral  RNA  load  can  reliably  indicate  the  presence  of  infectious  virus  in  a  sampled  tissue.  This  work  constitutes  the  largest  analysis  of  this  question  using  in  vivo  infection  data  from  individuals  with  known  exposure  conditions,  and  it  lays  crucial  groundwork  for  the  application  of  my  customized  statistical  approach  to  public  health  contexts.  I  demonstrate  that  total  RNA  measurements  can  indeed  predict  culture  positivity  with  a  remarkable  85%  accuracy  on  out-of-sample  data  as  long  as  predictions  also  account  for  other  factors,  including  exposure  conditions,  host  demographics,  and  assay  protocols.In  chapter  2,  I  conduct  the  first  large-scale  quantitative  analysis  of  respiratory  virus  challenge  experiments  in  non-human  primates  to  characterize  the  relative  impacts  of  exposure  route,  exposure  dose,  age,  sex,  and  species  on  within-host  dynamics.  I  show  that  exposure  route  more  strongly  modulates  the  probability,  onset,  peak,  and  conclusion  of  SARS-CoV-2  infection  across  the  respiratory  and  gastrointestinal  tracts  than  exposure  dose  or  demographic  factors.  I  also  show  that  infection  patterns  following  aerosol  inhalation  are  clearly  distinct  from  any  other  exposure  route,  including  intranasal  or  combined  intranasal/intratracheal  inoculation.  This  work  provides  the  most  comprehensive  and  quantitative  evidence  to  date  that  exposure  conditions  shape  infection  patterns  inside  hosts,  in  ways  that  affect  disease  risk  and  shedding  potential.In  chapter  3,  I  develop  a  novel  modeling  framework  that  formally  investigates  how  tissue  traits  (e.g.,  receptor  expression,  protease  availability)  and  connectivity  structure  interact  to  determine  spatiotemporal  infection  patterns  inside  hosts,  which  I  fit  to  the  data  from  nine  challenge  studies.  This  model  shows  that  SARS-CoV-2  infection  patterns  across  the  respiratory  and  gastrointestinal  tracts  are  shaped  by  high  rates  of  within-host  viral  dissemination.  I  also  show  that  infections  are  overall  more  successful  in  the  nose  and  throat  than  in  the  lung  and  lower  GI,  which  is  consistent  with  an  estimated  increase  in  the  local  infection  rates  at  the  lower  ambient  temperature  of  the  upper  respiratory  tract.Together,  these  chapters  demonstrate  that  meta-analysis  of  the  data  from  in  vivo  challenge  experiments  can  overcome  the  difficulties  arising  from  limited  sample  sizes  in  crucial  but  costly  animal  models  and  that  they  can  yield  robust  insights  beyond  those  attainable  from  individual  studies,  all  while  reducing  overall  animal  use  in  infectious  disease  research.  This  dissertation  focuses  on  characterizing  SARS-CoV-2  infections  in  non-human  primates,  but  the  methods  developed  here  can  be  readily  adapted  to  any  other  pathogen-host  system,  and  they  present  generalizable,  quantitative  approaches  to  answer  questions  at  the  frontier  of  virology.
■590    ▼aSchool  code:  0031.
■650  4▼aBiology
■650  4▼aVirology
■650  4▼aEcology
■650  4▼aBiostatistics
■653    ▼aBayesian  statistics
■653    ▼aComputational  biology
■653    ▼aDisease  ecology
■653    ▼aMeta-analysis
■653    ▼aViral  dynamics
■690    ▼a0306
■690    ▼a0720
■690    ▼a0329
■690    ▼a0308
■71020▼aUniversity  of  California,  Los  Angeles▼bBiology  0123.
■7730  ▼tDissertations  Abstracts  International▼g86-06B.
■790    ▼a0031
■791    ▼aPh.D.
■792    ▼a2024
■793    ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17165098▼nKERIS▼z이  자료의  원문은  한국교육학술정보원에서  제공합니다.

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