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Volume 25, Number 5—May 2019
Research Letter

Rickettsiales in Ticks Removed from Outdoor Workers, Southwest Georgia and Northwest Florida, USA

Elizabeth R. Gleim1Comments to Author , L. Mike Conner, Galina E. Zemtsova, Michael L. Levin, Pamela Wong, Madeleine A. Pfaff, and Michael J. Yabsley
Author affiliations: Joseph W. Jones Ecological Research Center at Ichauway, Newton, Georgia, USA (E.R. Gleim, L.M. Conner); Oxford College of Emory University, Oxford, Georgia, USA (E.R. Gleim, P. Wong); University of Georgia, Athens, Georgia, USA (E.R. Gleim, M.A. Pfaff, M.J. Yabsley); Centers for Disease Control and Prevention, Atlanta, Georgia, USA (G.E. Zemtsova, M.L. Levin)

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Prevalence of Ehrlichia chaffeensis, PME, and Rickettsia spp. in ticks submitted by outdoor workers, southwestern Georgia and northwestern Florida, USA*

Tick species and stage Months submitted No. positive ticks/no. tested (%)
Rickettsia spp.†
E. chaffeensis PME Rickettsia spp.
Amblyomma americanum, adults Feb–Sep 0/11 (0) 0/11 (0) 4/11 (36.4) 2 R. amblyommatis
A. americanum nymphs‡ Mar–Sep 0/43 (0) 0/43 (0) 12/43 (27.9) 9 R. amblyommatis
A. americanum larvae‡ Apr and Oct 0/5 (0) 0/5 (0) 1/5 (20.0) 1 R.amblyommatis
Amblyomma sp. nymphs Jun and Oct 0/3 (0) 0/3 (0) 1/3 (33.3) 1 R. amblyommatis§
Amblyomma sp. larvae Oct 0/5 (0) 0/5 (0) 0/5 (0)
A. maculatum adults May–Oct 1/83 (1.2) 2/83 (2.4)¶ 18/83 (21.7) 5 R. amblyommatis,§ 
4 R. parkeri,§ 1 Rickettsia sp. TR-39/TX125, 2 Candidatus R. andeanae
A. tuberculatum nymphs‡ Apr 0/5 (0) 0/5 (0) 1/5 (5.0) 1 novel SFG Rickettsia sp.
A. tuberculatum larvae‡ Feb# 0/182 (0) 0/182 (0) 10/182 (5.5)** 10 novel SFG Rickettsia sp.**
Dermacentor variabilis adults Jun–Aug 0/10 (0) 1/10 (10.0) 2/10 (20.0) 1 R. amblyommatis§
Ixodes scapularis adults Oct–Mar NT 0/15 (0) 7/15 (46.7) 4 Rickettsia sp. TR-39, 3 R. buchneri

*All Rickettsia spp. were identified by sequencing unless otherwise noted. NT, not tested; PME, Panola Mountain Ehrlichia sp., SFG, spotted fever group.
Rickettsia spp. for whom amplicons did not provide high-quality bidirectional sequences were categorized as unknown Rickettsia spp.
‡Minimum infection prevalence is no. positive tick pools/no. ticks tested.
§The following R. amblyommatis samples were identified by restriction fragment length polymorphism analysis: for 1 D. variabilis adult, 5 A. maculatum adults, and 1 Amblyomma sp. nymph; for A. americanum, 1 adult, 2 nymphs, and 1 larva. Three A. maculatum adults were also identified as containing R. parkeri positive by restriction fragment length polymorphism analysis.
¶Data included in Loftis et al. (5).
#Date was known only for 1 submission of 20 larvae. Dates for others were not provided when submitted.
**Data included in Zemtsova et al. (6).

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1Current affiliation: Hollins University, Roanoke, Virginia, USA.

Page created: April 17, 2019
Page updated: April 17, 2019
Page reviewed: April 17, 2019
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