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Geographic distribution and genetic diversity of the Ehrlichia sp. from Panola Mountain in Amblyomma americanum.

Loftis AD, Mixson TR, Stromdahl EY, Yabsley MJ, Garrison LE, Williamson PC, Fitak RR, Fuerst PA, Kelly DJ, Blount KW - BMC Infect. Dis. (2008)

Bottom Line: Two distinct clades, with 10.5% nucleic acid divergence over the 730 bp map1 sequence, were identified.These data suggest that the Panola Mountain Ehrlichia was not recently introduced to the United States; this agent has an extensive distribution throughout the range of its tick vector, has been present in some locations for several years, and displays genetic variability.Furthermore, people in several states were exposed to this agent through the bite of infected ticks, underscoring the potential public health risk of this emerging ehrlichiosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. adloftis@gmail.com

ABSTRACT

Background: A novel Ehrlichia, closely related to Ehrlichia ruminantium, was recently discovered from Panola Mountain State Park, GA, USA. We conducted a study to determine if this agent was recently introduced into the United States.

Methods: We developed a sensitive PCR assay based on the conserved gltA (citrate synthase) gene and tested DNA samples extracted from 1964 field-collected and 1835 human-biting Amblyomma americanum from 23 eastern states of the USA.

Results: The novel agent was detected in 36 ticks collected from 10 states between 1998 and 2006. Infected ticks were collected both from vegetation (n = 14, 0.7%) and from humans (n = 22, 1.2%). Fragments of the conserved gltA gene and the variable map1 gene were sequenced from positive samples. Two distinct clades, with 10.5% nucleic acid divergence over the 730 bp map1 sequence, were identified.

Conclusion: These data suggest that the Panola Mountain Ehrlichia was not recently introduced to the United States; this agent has an extensive distribution throughout the range of its tick vector, has been present in some locations for several years, and displays genetic variability. Furthermore, people in several states were exposed to this agent through the bite of infected ticks, underscoring the potential public health risk of this emerging ehrlichiosis.

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Related in: MedlinePlus

Genetic diversity of the Panola Mountain Ehrlichia sp. Phylogenetic reconstruction of the map1 predicted amino acid sequences from 31 Amblyomma americanum harboring DNA from the Panola Mountain Ehrlichia sp. (PME). Numbers indicate the bootstrap support for each node, as a percentage of 1000 replicates, and the scale represents the number of changes per 100 residues.
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Figure 2: Genetic diversity of the Panola Mountain Ehrlichia sp. Phylogenetic reconstruction of the map1 predicted amino acid sequences from 31 Amblyomma americanum harboring DNA from the Panola Mountain Ehrlichia sp. (PME). Numbers indicate the bootstrap support for each node, as a percentage of 1000 replicates, and the scale represents the number of changes per 100 residues.

Mentions: Phylogenetic reconstructions based on the map1 amino acid sequences were attempted (Figure 2) using all of the DNA sequences that were 730 bp in length. The sequences from the ticks formed two distinct clades, with 100% bootstrap support for each clade (1000 psuedoreplicates), and they formed a cluster within the larger taxonomic group of E. ruminantium strains in 82% of the replicates. The PME/E. ruminantium clade was a sister taxa to E. chaffeensis and E. canis in 100% of the replicates. Bootstrap support for separation of PME and E. ruminantium into separate taxa was weak (< 500/1000).


Geographic distribution and genetic diversity of the Ehrlichia sp. from Panola Mountain in Amblyomma americanum.

Loftis AD, Mixson TR, Stromdahl EY, Yabsley MJ, Garrison LE, Williamson PC, Fitak RR, Fuerst PA, Kelly DJ, Blount KW - BMC Infect. Dis. (2008)

Genetic diversity of the Panola Mountain Ehrlichia sp. Phylogenetic reconstruction of the map1 predicted amino acid sequences from 31 Amblyomma americanum harboring DNA from the Panola Mountain Ehrlichia sp. (PME). Numbers indicate the bootstrap support for each node, as a percentage of 1000 replicates, and the scale represents the number of changes per 100 residues.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2394526&req=5

Figure 2: Genetic diversity of the Panola Mountain Ehrlichia sp. Phylogenetic reconstruction of the map1 predicted amino acid sequences from 31 Amblyomma americanum harboring DNA from the Panola Mountain Ehrlichia sp. (PME). Numbers indicate the bootstrap support for each node, as a percentage of 1000 replicates, and the scale represents the number of changes per 100 residues.
Mentions: Phylogenetic reconstructions based on the map1 amino acid sequences were attempted (Figure 2) using all of the DNA sequences that were 730 bp in length. The sequences from the ticks formed two distinct clades, with 100% bootstrap support for each clade (1000 psuedoreplicates), and they formed a cluster within the larger taxonomic group of E. ruminantium strains in 82% of the replicates. The PME/E. ruminantium clade was a sister taxa to E. chaffeensis and E. canis in 100% of the replicates. Bootstrap support for separation of PME and E. ruminantium into separate taxa was weak (< 500/1000).

Bottom Line: Two distinct clades, with 10.5% nucleic acid divergence over the 730 bp map1 sequence, were identified.These data suggest that the Panola Mountain Ehrlichia was not recently introduced to the United States; this agent has an extensive distribution throughout the range of its tick vector, has been present in some locations for several years, and displays genetic variability.Furthermore, people in several states were exposed to this agent through the bite of infected ticks, underscoring the potential public health risk of this emerging ehrlichiosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. adloftis@gmail.com

ABSTRACT

Background: A novel Ehrlichia, closely related to Ehrlichia ruminantium, was recently discovered from Panola Mountain State Park, GA, USA. We conducted a study to determine if this agent was recently introduced into the United States.

Methods: We developed a sensitive PCR assay based on the conserved gltA (citrate synthase) gene and tested DNA samples extracted from 1964 field-collected and 1835 human-biting Amblyomma americanum from 23 eastern states of the USA.

Results: The novel agent was detected in 36 ticks collected from 10 states between 1998 and 2006. Infected ticks were collected both from vegetation (n = 14, 0.7%) and from humans (n = 22, 1.2%). Fragments of the conserved gltA gene and the variable map1 gene were sequenced from positive samples. Two distinct clades, with 10.5% nucleic acid divergence over the 730 bp map1 sequence, were identified.

Conclusion: These data suggest that the Panola Mountain Ehrlichia was not recently introduced to the United States; this agent has an extensive distribution throughout the range of its tick vector, has been present in some locations for several years, and displays genetic variability. Furthermore, people in several states were exposed to this agent through the bite of infected ticks, underscoring the potential public health risk of this emerging ehrlichiosis.

Show MeSH
Related in: MedlinePlus