County-level surveillance for the American dog tick (Dermacentor variabilis) and Rickettsia species in Kentucky

Callista W. Vandegriff; Jun Seok Ryoo; Maria C. Carrasquilla; Anna R. Pasternak; Wayne T. Sanderson; Subba R. Palli

doi:10.1038/s41598-026-37422-0

County-level surveillance for the American dog tick (Dermacentor variabilis) and Rickettsia species in Kentucky

Callista W. Vandegriff
, Jun Seok Ryoo
, Maria C. Carrasquilla
, Anna R. Pasternak
, Wayne T. Sanderson
, Subba R. Palli

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Abstract

Spotted fever group (SFG) rickettsiosis includes a group of illnesses with similar symptoms caused by Rickettsia species bacteria. While Rickettsia rickettsii, the agent of Rocky Mountain spotted fever (RMSF) is a well-known pathogen, other SFG Rickettsia spp. can infect ticks and occasionally contribute to human disease. We conducted county-level surveillance of Dermacentor variabilis ticks in Kentucky to characterize the distribution and diversity of SFG Rickettsia. Ticks were collected from the environment from 2019 to 2024 by dragging a white cloth and through our Kentucky Tick Submission Program. In total, 2,023 D. variabilis ticks were collected from 114 counties. Rickettsia species were detected in 1% of Dermacentor variabilis ticks, including R. montanensis (0.47%), R. amblyommatis (0.13%), and R. parkeri (0.13%). These findings indicate that, while SFG Rickettsia are present at low levels in D. variabilis ticks in Kentucky, continued surveillance in counties with reported SFG rickettsiosis cases is essential to improve clinical recognition and guide public health efforts to monitor and prevent SFG rickettsiosis.

Original language	English
Article number	7404
Journal	Scientific Reports
Volume	16
Issue number	1
DOIs	https://doi.org/10.1038/s41598-026-37422-0
State	Published - Dec 2026

Bibliographical note

Publisher Copyright:
© The Author(s) 2026.

Funding

This work was supported by the Kentucky Department for Public Health, the Agricultural Safety and Health (ASH) Training Program of the Central Appalachian Regional Education and Research Center (CARERC) traineeship awarded to CWV and ARP, and the National Institute for Occupational Safety and Health (NIOSH) grant awarded to JSR.

Funders
National Children’s Center for Rural and Agricultural Safety and Health
National Institute for Occupational Safety and Health
Department for Public Health, Cabinet for Health and Family Services
ARP-IR
Central Appalachian Regional Education and Research Center

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Keywords

Dermacentor variabilis
Rickettsia
Spotted fever group
Tick surveillance

ASJC Scopus subject areas

General

Access to Document

10.1038/s41598-026-37422-0

Cite this

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title = "County-level surveillance for the American dog tick (Dermacentor variabilis) and Rickettsia species in Kentucky",

abstract = "Spotted fever group (SFG) rickettsiosis includes a group of illnesses with similar symptoms caused by Rickettsia species bacteria. While Rickettsia rickettsii, the agent of Rocky Mountain spotted fever (RMSF) is a well-known pathogen, other SFG Rickettsia spp. can infect ticks and occasionally contribute to human disease. We conducted county-level surveillance of Dermacentor variabilis ticks in Kentucky to characterize the distribution and diversity of SFG Rickettsia. Ticks were collected from the environment from 2019 to 2024 by dragging a white cloth and through our Kentucky Tick Submission Program. In total, 2,023 D. variabilis ticks were collected from 114 counties. Rickettsia species were detected in 1\% of Dermacentor variabilis ticks, including R. montanensis (0.47\%), R. amblyommatis (0.13\%), and R. parkeri (0.13\%). These findings indicate that, while SFG Rickettsia are present at low levels in D. variabilis ticks in Kentucky, continued surveillance in counties with reported SFG rickettsiosis cases is essential to improve clinical recognition and guide public health efforts to monitor and prevent SFG rickettsiosis.",

keywords = "Dermacentor variabilis, Rickettsia, Spotted fever group, Tick surveillance",

author = "Vandegriff, \{Callista W.\} and Ryoo, \{Jun Seok\} and Carrasquilla, \{Maria C.\} and Pasternak, \{Anna R.\} and Sanderson, \{Wayne T.\} and Palli, \{Subba R.\}",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2026.",

year = "2026",

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doi = "10.1038/s41598-026-37422-0",

language = "English",

volume = "16",

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AU - Vandegriff, Callista W.

AU - Ryoo, Jun Seok

AU - Carrasquilla, Maria C.

AU - Pasternak, Anna R.

AU - Sanderson, Wayne T.

AU - Palli, Subba R.

N1 - Publisher Copyright: © The Author(s) 2026.

PY - 2026/12

Y1 - 2026/12

N2 - Spotted fever group (SFG) rickettsiosis includes a group of illnesses with similar symptoms caused by Rickettsia species bacteria. While Rickettsia rickettsii, the agent of Rocky Mountain spotted fever (RMSF) is a well-known pathogen, other SFG Rickettsia spp. can infect ticks and occasionally contribute to human disease. We conducted county-level surveillance of Dermacentor variabilis ticks in Kentucky to characterize the distribution and diversity of SFG Rickettsia. Ticks were collected from the environment from 2019 to 2024 by dragging a white cloth and through our Kentucky Tick Submission Program. In total, 2,023 D. variabilis ticks were collected from 114 counties. Rickettsia species were detected in 1% of Dermacentor variabilis ticks, including R. montanensis (0.47%), R. amblyommatis (0.13%), and R. parkeri (0.13%). These findings indicate that, while SFG Rickettsia are present at low levels in D. variabilis ticks in Kentucky, continued surveillance in counties with reported SFG rickettsiosis cases is essential to improve clinical recognition and guide public health efforts to monitor and prevent SFG rickettsiosis.

AB - Spotted fever group (SFG) rickettsiosis includes a group of illnesses with similar symptoms caused by Rickettsia species bacteria. While Rickettsia rickettsii, the agent of Rocky Mountain spotted fever (RMSF) is a well-known pathogen, other SFG Rickettsia spp. can infect ticks and occasionally contribute to human disease. We conducted county-level surveillance of Dermacentor variabilis ticks in Kentucky to characterize the distribution and diversity of SFG Rickettsia. Ticks were collected from the environment from 2019 to 2024 by dragging a white cloth and through our Kentucky Tick Submission Program. In total, 2,023 D. variabilis ticks were collected from 114 counties. Rickettsia species were detected in 1% of Dermacentor variabilis ticks, including R. montanensis (0.47%), R. amblyommatis (0.13%), and R. parkeri (0.13%). These findings indicate that, while SFG Rickettsia are present at low levels in D. variabilis ticks in Kentucky, continued surveillance in counties with reported SFG rickettsiosis cases is essential to improve clinical recognition and guide public health efforts to monitor and prevent SFG rickettsiosis.

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KW - Rickettsia

KW - Spotted fever group

KW - Tick surveillance

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ER -

County-level surveillance for the American dog tick (Dermacentor variabilis) and Rickettsia species in Kentucky

Abstract

Bibliographical note

Funding

UN SDGs

Keywords

ASJC Scopus subject areas

Access to Document

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