J Clin Microbiol. 2003 December; 41(12): 5557–5562.
Copyright © 2003, American Society for Microbiology
Evidence of Borrelia lonestari DNA in Amblyomma americanum (Acari: Ixodidae) Removed from Humans
Ellen Y. Stromdahl,1* Phillip C. Williamson,2 Thomas M. Kollars, Jr.,1 Sandra R. Evans,1 Ryan K. Barry,1 Mary A. Vince,1 and Nicole A. Dobbs2
Entomological Sciences Program, U.S. Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, Maryland 21010-5403,1 DNA Identity Laboratory, Department of Pathology and Anatomy, University of North Texas Health Science Center, Ft. Worth, Texas 76107-26992
*Corresponding author. Mailing address: U.S. Army Center for Health Promotion and Preventive Medicine, Entomological Sciences Program, 5158 Blackhawk Rd., Aberdeen Proving Ground, MD 21010-5403. Phone: (410) 436-3613. Fax: (410) 436-2037. E-mail: Ellen.Stromdahl@apg.amedd.army.mil.
Received May 20, 2003; Revised August 19, 2003; Accepted August 28, 2003.
This article has been cited by other articles in PMC.
We used a nested PCR with Borrelia flagellin gene (flaB) primers and DNA sequencing to determine if Borrelia lonestari was present inAmblyomma americanum ticks removed from military personnel and sent to the Tick-Borne Disease Laboratory of the U.S. Army Center for Health Promotion and Preventive Medicine.
In our preliminary investigation, we detected Borrelia sequences in 19 of 510 A. americanum adults and nymphs from Ft. A. P. Hill, Va. During the 2001 tick season, the flaBprimers were used to test all A. americanum samples as they were received, and 29 of 2,358 A. americanum samples tested individually or in small pools were positive.
PCRs with 2,146 A. americanum samples in 2002 yielded 26 more Borrelia-positive samples. The positive ticks in 2001 and 2002 were from Arkansas, Delaware, Kansas, Kentucky, Maryland, New Jersey, North Carolina, Tennessee, and Virginia. The last positive sample of the 2001 season was a pool of larvae. To further investigate larval infection, we collected and tested questing A. americanum larvae from Aberdeen Proving Ground, Md.; 4 of 33 pools (40 larvae per pool) were positive.
Infection of unfed larvae provides evidence of the maintenance of B. lonestari by means of transovarial transmission. Sequence analysis revealed that the amplicons were identical to sequences of the B. lonestari flaB gene in GenBank. Despite the low prevalence of infection, the risk of B. lonestari transmission may be magnified because A. americanum is often abundant and aggressive, and many tick bite victims receive multiple bites.