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Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut

The genetic diversity of pathogens, and interactions between genotypes, can strongly influence pathogen phenotypes such as transmissibility and virulence. For vector-borne pathogens, both mammalian hosts and arthropod vectors may limit pathogen genotypic diversity (number of unique genotypes circula...

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Autores principales: Reif, Kathryn E., Palmer, Guy H., Crowder, David W., Ueti, Massaro W., Noh, Susan M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4231110/
https://www.ncbi.nlm.nih.gov/pubmed/25392914
http://dx.doi.org/10.1371/journal.ppat.1004499
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author Reif, Kathryn E.
Palmer, Guy H.
Crowder, David W.
Ueti, Massaro W.
Noh, Susan M.
author_facet Reif, Kathryn E.
Palmer, Guy H.
Crowder, David W.
Ueti, Massaro W.
Noh, Susan M.
author_sort Reif, Kathryn E.
collection PubMed
description The genetic diversity of pathogens, and interactions between genotypes, can strongly influence pathogen phenotypes such as transmissibility and virulence. For vector-borne pathogens, both mammalian hosts and arthropod vectors may limit pathogen genotypic diversity (number of unique genotypes circulating in an area) by preventing infection or transmission of particular genotypes. Mammalian hosts often act as “ecological filters” for pathogen diversity, where novel variants are frequently eliminated because of stochastic events or fitness costs. However, whether vectors can serve a similar role in limiting pathogen diversity is less clear. Here we show using Francisella novicida and a natural tick vector of Francisella spp. (Dermacentor andersoni), that the tick vector acted as a stronger ecological filter for pathogen diversity compared to the mammalian host. When both mice and ticks were exposed to mixtures of F. novicida genotypes, significantly fewer genotypes co-colonized ticks compared to mice. In both ticks and mice, increased genotypic diversity negatively affected the recovery of available genotypes. Competition among genotypes contributed to the reduction of diversity during infection of the tick midgut, as genotypes not recovered from tick midguts during mixed genotype infections were recovered from tick midguts during individual genotype infection. Mediated by stochastic and selective forces, pathogen genotype diversity was markedly reduced in the tick. We incorporated our experimental results into a model to demonstrate how vector population dynamics, especially vector-to-host ratio, strongly affected pathogen genotypic diversity in a population over time. Understanding pathogen genotypic population dynamics will aid in identification of the variables that most strongly affect pathogen transmission and disease ecology.
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spelling pubmed-42311102014-11-18 Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut Reif, Kathryn E. Palmer, Guy H. Crowder, David W. Ueti, Massaro W. Noh, Susan M. PLoS Pathog Research Article The genetic diversity of pathogens, and interactions between genotypes, can strongly influence pathogen phenotypes such as transmissibility and virulence. For vector-borne pathogens, both mammalian hosts and arthropod vectors may limit pathogen genotypic diversity (number of unique genotypes circulating in an area) by preventing infection or transmission of particular genotypes. Mammalian hosts often act as “ecological filters” for pathogen diversity, where novel variants are frequently eliminated because of stochastic events or fitness costs. However, whether vectors can serve a similar role in limiting pathogen diversity is less clear. Here we show using Francisella novicida and a natural tick vector of Francisella spp. (Dermacentor andersoni), that the tick vector acted as a stronger ecological filter for pathogen diversity compared to the mammalian host. When both mice and ticks were exposed to mixtures of F. novicida genotypes, significantly fewer genotypes co-colonized ticks compared to mice. In both ticks and mice, increased genotypic diversity negatively affected the recovery of available genotypes. Competition among genotypes contributed to the reduction of diversity during infection of the tick midgut, as genotypes not recovered from tick midguts during mixed genotype infections were recovered from tick midguts during individual genotype infection. Mediated by stochastic and selective forces, pathogen genotype diversity was markedly reduced in the tick. We incorporated our experimental results into a model to demonstrate how vector population dynamics, especially vector-to-host ratio, strongly affected pathogen genotypic diversity in a population over time. Understanding pathogen genotypic population dynamics will aid in identification of the variables that most strongly affect pathogen transmission and disease ecology. Public Library of Science 2014-11-13 /pmc/articles/PMC4231110/ /pubmed/25392914 http://dx.doi.org/10.1371/journal.ppat.1004499 Text en https://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
spellingShingle Research Article
Reif, Kathryn E.
Palmer, Guy H.
Crowder, David W.
Ueti, Massaro W.
Noh, Susan M.
Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut
title Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut
title_full Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut
title_fullStr Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut
title_full_unstemmed Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut
title_short Restriction of Francisella novicida Genetic Diversity during Infection of the Vector Midgut
title_sort restriction of francisella novicida genetic diversity during infection of the vector midgut
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4231110/
https://www.ncbi.nlm.nih.gov/pubmed/25392914
http://dx.doi.org/10.1371/journal.ppat.1004499
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