Detection of Vector-Borne Agents in Lone Star Ticks, Amblyomma americanum (Acari: Ixodidae), From Mississippi

ORCID

Goddard: https://orcid.org/0000-0002-2617-7141

MSU Affiliation

College of Veterinary Medicine; Department of Basic Sciences; College of Agriculture and Life Sciences; Department of Entomology and Plant Pathology

Creation Date

2026-09-30

Abstract

In this study, we evaluated Amblyomma americanum (lone star tick) in Mississippi for the presence of Ehrlichia chaffeensis, causative agent of human monocytic ehrlichiosis; Ehrlichia ewingii, causative agent of human and canine granulocytic ehrlichiosis; Borrelia lonestari, putative agent of southern tick-associated rash illness; Francisella tularensis, the agent of tularemia; and Rickettsia spp., particularly R. amblyommii, a suspected pathogen, We collected adult A. americanum from four regions of Mississippi: Northeast, Northwest, Southeast, and East. Of the ticks collected, 192 were dissected and DNA was extracted for nested polymerase chain reaction (PCR) assays to detect the above bacteria. In all, 3% of tick extracts had evidence of Borrelia sp., 4% for E. chaffeensis, 6% for E. ewingii, and 44% for a Rickettsia species. As determined by sequencing, most Rickettsia spp, were R. amblyommii. In addition, extracts from 42 pools (total of 950) of larval A. americanum collected in Southwest Mississippi were tested for the presence of E. chaffeensis and Rickettsia species. Of these extracts from pools, nine of 37 (24%) were PCR positive for a Rickettsia sp., most often, R. amblyommii; none had evidence of E. chaffeensis, supporting the ability of lone star ticks to transovarially transmit R. amblyommii, but not E. chaffeensis. This study demonstrates E. chaffeensis, E. ewingii, "B. lonestari", and R. amblyommii in A. americanum by PCR for the first time in Mississippi. Understanding the prevalence and epidemiology of these agents in Mississippi should increase awareness of tick-borne disease in the medical community. © 2010 Entomological Society of America.

Keywords

Amblyomma americanum, tick-borne agents, MS

Publication Date

5-1-2010

Publication Title

Journal of Medical Entomology

Publisher

Oxford University Press; Entomological Society of America

First Page

473

Last Page

476

Rights

© 2010 Entomological Society of America

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Digital Object Identifier (DOI)

https://doi.org/10.1603/ME09263