title: Borrelia burgdorferi not confirmed in human-biting Amblyomma americanum ticks from the southeastern United States.
abstract: The predominant human-biting tick throughout the southeastern United States is Amblyomma americanum. Its ability to transmit pathogens causing Lyme disease-like illnesses is a subject of ongoing controversy. Results of previous testing by the Department of Defense Human Tick Test Kit Program and other laboratories indicated that it is highly unlikely that A. americanum transmits any pathogen that causes Lyme disease. In contrast, a recent publication by Clark and colleagues (K. L. Clark, B. Leydet, and S. Hartman, Int. J. Med. Sci. 10:915-931, 2013) reported detection of Lyme group Borrelia in A. americanum using a nested-flagellin-gene PCR. We evaluated this assay by using it and other assays to test 1,097 A. americanum ticks collected from humans. Using the Clark assay, in most samples we observed nonspecific amplification and nonrepeatability of results on subsequent testing of samples. Lack of reaction specificity and repeatability is consistent with mispriming, likely due to high primer concentrations and low annealing temperatures in this protocol. In six suspect-positive samples, Borrelia lonestari was identified by sequencing of an independent gene region; this is not a Lyme group spirochete and is not considered zoonotic. B. burgdorferi was weakly amplified from one pool using some assays, but not others, and attempts to sequence the amplicon of this pool failed, as did attempts to amplify and sequence B. burgdorferi from the five individual samples comprising this pool. Therefore, B. burgdorferi was not confirmed in any sample. Our results do not support the hypothesis that A. americanum ticks are a vector for Lyme group Borrelia infections.
authors: U.S. Army Public Health Command, Aberdeen Proving Ground, Maryland, USA Ellen.y.stromdahl.civ@mail.mil.
authors: Ellen Y
authors: EY
authors: Stromdahl
authors: U.S. Army Public Health Command, Aberdeen Proving Ground, Maryland, USA Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA.
authors: Robyn M
authors: RM
authors: Nadolny
authors: U.S. Army Edgewood Chemical and Biological Center, Aberdeen Proving Ground, Maryland, USA Science and Technology Corp., Hampton, Virginia, USA.
authors: Jennifer A
authors: JA
authors: Gibbons
authors: Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA.
authors: Lisa D
authors: LD
authors: Auckland
authors: U.S. Army Public Health Command, Aberdeen Proving Ground, Maryland, USA.
authors: Mary A
authors: MA
authors: Vince
authors: U.S. Army Public Health Command, Aberdeen Proving Ground, Maryland, USA.
authors: Chad E
authors: CE
authors: Elkins
authors: U.S. Army Public Health Command, Aberdeen Proving Ground, Maryland, USA.
authors: Michael P
authors: MP
authors: Murphy
authors: Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, USA.
authors: Graham J
authors: GJ
authors: Hickling
authors: Ibis Biosciences, Carlsbad, California, USA.
authors: Mark W
authors: MW
authors: Eshoo
authors: Ibis Biosciences, Carlsbad, California, USA.
authors: Heather E
authors: HE
authors: Carolan
authors: Ibis Biosciences, Carlsbad, California, USA.
authors: Chris D
authors: CD
authors: Crowder
authors: Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors: Mark A
authors: MA
authors: Pilgard
authors: Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA.
authors: Sarah A
authors: SA
authors: Hamer
mesh_terms: D000818:Animals; D025065:Borrelia burgdorferi / Q000302:isolation & purification*; D004772:Entomology / Q000379:methods; D005260:Female; D006801:Humans; D026863:Ixodidae / Q000382:microbiology*; D008297:Male; D025202:Molecular Diagnostic Techniques / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015144:Southeastern United States