Rickettsiae in Gulf Coast Ticks, Arkansas, USA

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Rickettsiae in Gulf Coast Ticks, Arkansas, USA

_EID Journal Home_ (http://www.cdc.gov/ncidod/eid/index.htm) > _Volume 16,

Number 5–May 2010_ (http://www.cdc.gov/ncidod/eid/index.htm)

Volume 16, Number 5–May 2010

Dispatch

Rickettsiae in Gulf Coast Ticks, Arkansas, USA

Rebecca Trout, (http://www.cdc.gov/eid/content/16/5/830.htm#comment) C.

Dayton Steelman, Allen L. Szalanski, and Phillip C. Williamson

Author affiliations: University of Arkansas, Fayetteville, Arkansas, USA

(R. Trout, C.D. Steelman, A.L. Szalanski); and University of North Texas

Health Science Center, Fort Worth, Texas, USA (P.C. Williamson)

_Suggested citation for this article_

(http://www.cdc.gov/eid/content/16/5/830.htm#cit)

 

Abstract

To determine the cause of spotted fever cases in the southern United

States, we screened Gulf Coast ticks (Amblyomma maculatum) collected in

Arkansas

for rickettsiae. Of the screened ticks, 30% had PCR amplicons consistent

with Rickettsia parkeri or Candidatus Rickettsia amblyommii.

The Centers for Disease Control and Prevention identified Arkansas as a

leading state for the incidence of Rocky Mountain spotted fever (causative

agent Rickettsia rickettsii) and reported >15 cases per 1,000,000 persons in

2002 (_1_ (http://www.cdc.gov/eid/content/16/5/830.htm#1) ). Given the

known cross-reactivity of serologic testing results for spotted fever group

(SFG) rickettsia, it is unclear if cases outside the natural range of the

vectors for R. rickettsii are misdiagnosed, if the pathogen is less virulent

than previously suggested, or if additional rickettsiae are responsible for

pathogenesis (_2_ (http://www.cdc.gov/eid/content/16/5/830.htm#1) ).

Recently, the Gulf Coast tick (Amblyomma maculatum) was identified as the

primary vector of R. parkeri, a newly described pathogen that causes

disease symptoms similar to Rocky Mountain spotted fever (_3_

(http://www.cdc.gov/eid/content/16/5/830.htm#1) ). R. parkeri has previously

been identified in

A. maculatum tick specimens collected in the southeastern United States

(_4_ (http://www.cdc.gov/eid/content/16/5/830.htm#1) ) and from a human

biopsy specimen in Virginia, USA (_5_

(http://www.cdc.gov/eid/content/16/5/830.htm#1) ). We have identified A.

maculatum ticks collected from canids,

felids, white-tailed deer, and a cow from locations throughout Arkansas (_6_

(http://www.cdc.gov/eid/content/16/5/830.htm#1) ). Notably, R. amblyommii has

been identified as a potential pathogen and is found in lone star ticks (A.

americanum) (_7,8_ (http://www.cdc.gov/eid/content/16/5/830.htm#1) ). We

report the presence of DNA consistent with that of Candidatus Rickettsia

amblyommii and R. parkeri in A. maculatum ticks in Arkansas.

full text at: _http://www.cdc.gov/eid/content/16/5/830.htm_

(http://www.cdc.gov/eid/content/16/5/830.htm)