Volume 25, Number 5—May 2019
Research Letter
Rickettsiales in Ticks Removed from Outdoor Workers, Southwest Georgia and Northwest Florida, USA
Table
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).
References
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1Current affiliation: Hollins University, Roanoke, Virginia, USA.