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Francisella tularensis in the United States.

Farlow J, Wagner DM, Dukerich M, Stanley M, Chu M, Kubota K, Petersen J, Keim P - Emerging Infect. Dis. (2005)

Bottom Line: Phylogenetic analyses showed patterns similar to recently reported global-scale analyses.We observed clustering by subspecies, low genetic diversity within F. tularensis subsp. holarctica, and division of F. tularensis subsp. tularensis into 2 distinct subpopulations: A.I. and A.II.The 2 F. tularensis subsp. tularensis subpopulations also represent geographically distinct groups; A.I. occurs primarily in the central United States, and A.II. occurs primarily in the western United States.

View Article: PubMed Central - PubMed

Affiliation: Northern Arizona University, Flagstaff, Arizona 86011-5640, USA.

ABSTRACT
The causative agent of tularemia, Francisella tularensis, is a formidable biologic agent that occurs naturally throughout North America. We examined genetic and spatial diversity patterns among 161 US F. tularensis isolates by using a 24-marker multiple-locus variable-number tandem repeat analysis (MLVA) system. MLVA identified 126 unique genotypes. Phylogenetic analyses showed patterns similar to recently reported global-scale analyses. We observed clustering by subspecies, low genetic diversity within F. tularensis subsp. holarctica, and division of F. tularensis subsp. tularensis into 2 distinct subpopulations: A.I. and A.II. The 2 F. tularensis subsp. tularensis subpopulations also represent geographically distinct groups; A.I. occurs primarily in the central United States, and A.II. occurs primarily in the western United States. These spatial distributions are correlated with geographic ranges of particular vectors, hosts of tularemia, and abiotic factors. These correlates provide testable hypotheses regarding ecologic factors associated with maintaining tularemia foci.

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Genetic relationships among 48 North American Francisella tularensis subsp. tularensis A.I. subpopulation isolates based upon allelic differences at 24 variable number tandem repeat (VNTR) markers. County, state, and year of isolation are specified to the right of each branch or clade. G indicates number of distinct VNTR marker genotypes, dots indicate host-linked isolates, boxed designation indicates prominent F. tularensis subsp. tularensis laboratory strain SCHU S4, and asterisks indicate isolates with an unknown year of isolation.
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Figure 1: Genetic relationships among 48 North American Francisella tularensis subsp. tularensis A.I. subpopulation isolates based upon allelic differences at 24 variable number tandem repeat (VNTR) markers. County, state, and year of isolation are specified to the right of each branch or clade. G indicates number of distinct VNTR marker genotypes, dots indicate host-linked isolates, boxed designation indicates prominent F. tularensis subsp. tularensis laboratory strain SCHU S4, and asterisks indicate isolates with an unknown year of isolation.

Mentions: Neighbor-joining analysis of MLVA data identified 4 major genetic groups among the 161 North American F. tularensis isolates: F. tularensis subsp. tularensis subpopulation A.I., F. tularensis subsp. tularensis subpopulation A.II., F. tularensis subsp. holarctica, and F. tularensis subsp. novicida (Figures 1–5). The genetic groupings observed are consistent with the major genetics groups we described previously (13). In all cases, assignment of isolates to these genetic groups was consistent with their existing subspecies designations, which were based upon immunofluorescent, biochemical, and other molecular tests.


Francisella tularensis in the United States.

Farlow J, Wagner DM, Dukerich M, Stanley M, Chu M, Kubota K, Petersen J, Keim P - Emerging Infect. Dis. (2005)

Genetic relationships among 48 North American Francisella tularensis subsp. tularensis A.I. subpopulation isolates based upon allelic differences at 24 variable number tandem repeat (VNTR) markers. County, state, and year of isolation are specified to the right of each branch or clade. G indicates number of distinct VNTR marker genotypes, dots indicate host-linked isolates, boxed designation indicates prominent F. tularensis subsp. tularensis laboratory strain SCHU S4, and asterisks indicate isolates with an unknown year of isolation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3367644&req=5

Figure 1: Genetic relationships among 48 North American Francisella tularensis subsp. tularensis A.I. subpopulation isolates based upon allelic differences at 24 variable number tandem repeat (VNTR) markers. County, state, and year of isolation are specified to the right of each branch or clade. G indicates number of distinct VNTR marker genotypes, dots indicate host-linked isolates, boxed designation indicates prominent F. tularensis subsp. tularensis laboratory strain SCHU S4, and asterisks indicate isolates with an unknown year of isolation.
Mentions: Neighbor-joining analysis of MLVA data identified 4 major genetic groups among the 161 North American F. tularensis isolates: F. tularensis subsp. tularensis subpopulation A.I., F. tularensis subsp. tularensis subpopulation A.II., F. tularensis subsp. holarctica, and F. tularensis subsp. novicida (Figures 1–5). The genetic groupings observed are consistent with the major genetics groups we described previously (13). In all cases, assignment of isolates to these genetic groups was consistent with their existing subspecies designations, which were based upon immunofluorescent, biochemical, and other molecular tests.

Bottom Line: Phylogenetic analyses showed patterns similar to recently reported global-scale analyses.We observed clustering by subspecies, low genetic diversity within F. tularensis subsp. holarctica, and division of F. tularensis subsp. tularensis into 2 distinct subpopulations: A.I. and A.II.The 2 F. tularensis subsp. tularensis subpopulations also represent geographically distinct groups; A.I. occurs primarily in the central United States, and A.II. occurs primarily in the western United States.

View Article: PubMed Central - PubMed

Affiliation: Northern Arizona University, Flagstaff, Arizona 86011-5640, USA.

ABSTRACT
The causative agent of tularemia, Francisella tularensis, is a formidable biologic agent that occurs naturally throughout North America. We examined genetic and spatial diversity patterns among 161 US F. tularensis isolates by using a 24-marker multiple-locus variable-number tandem repeat analysis (MLVA) system. MLVA identified 126 unique genotypes. Phylogenetic analyses showed patterns similar to recently reported global-scale analyses. We observed clustering by subspecies, low genetic diversity within F. tularensis subsp. holarctica, and division of F. tularensis subsp. tularensis into 2 distinct subpopulations: A.I. and A.II. The 2 F. tularensis subsp. tularensis subpopulations also represent geographically distinct groups; A.I. occurs primarily in the central United States, and A.II. occurs primarily in the western United States. These spatial distributions are correlated with geographic ranges of particular vectors, hosts of tularemia, and abiotic factors. These correlates provide testable hypotheses regarding ecologic factors associated with maintaining tularemia foci.

Show MeSH
Related in: MedlinePlus