Survey of Borreliae in ticks, canines, and white-tailed deer from Arkansas, U.S.A.

<p>Abstract</p> <p>Background</p> <p>In the Eastern and Upper Midwestern regions of North America, <it>Ixodes scapularis</it> (L.) is the most abundant tick species encountered by humans and the primary vector of <it>B. burgdorferi,</it> whereas in the southeastern region <it>Amblyomma americanum</it> (Say) is the most abundant tick species encountered by humans but cannot transmit <it>B. burgdorferi.</it> Surveys of Borreliae in ticks have been conducted in the southeastern United States and often these surveys identify <it>B. lonestari</it> as the primary <it>Borrelia</it> species, surveys have not included Arkansas ticks, canines, or white-tailed deer and <it>B. lonestari</it> is not considered pathogenic. The objective of this study was to identify <it>Borrelia</it> species within Arkansas by screening ticks (n = 2123), canines (n = 173), and white-tailed deer (n = 228) to determine the identity and locations of Borreliae endemic to Arkansas using PCR amplification of the flagellin (<it>flaB)</it> gene.</p> <p>Methods</p> <p>Field collected ticks from canines and from hunter-killed white-tailed were identified to species and life stage. After which, ticks and their hosts were screened for the presence of <it>Borrelia</it> using PCR to amplify the <it>flaB</it> gene. A subset of the positive samples was confirmed with bidirectional sequencing.</p> <p>Results</p> <p>In total 53 (21.2%) white-tailed deer, ten (6%) canines, and 583 (27.5%) Ixodid ticks (252 <it>Ixodes scapularis</it>, 161 <it>A. americanum</it>, 88 <it>Rhipicephalus sanguineus</it>, 50 <it>Amblyomma maculatum,</it> 19 <it>Dermacentor variabilis,</it> and 13 unidentified <it>Amblyomma</it> species) produced a <it>Borrelia flaB</it> amplicon. Of the positive ticks, 324 (22.7%) were collected from canines (151 <it>A. americanum,</it> 78 <it>R. sanguineus</it>, 43 <it>I. scapularis,</it> 26 <it>A. maculatum,</it> 18 <it>D. variabilis</it>, and 8 <it>Amblyomma</it> species) and 259 (37.2%) were collected from white-tailed deer (209 <it>I. scapularis,</it> 24 <it>A. maculatum,</it> 10 <it>A. americanum,</it> 10 <it>R. sanguineus</it>, 1 <it>D. variabilis</it>, and 5 <it>Amblyomma</it> species). None of the larvae were PCR positive. A majority of the <it>flaB</it> amplicons were homologous with <it>B. lonestari</it> sequences: 281 of the 296 sequenced ticks, 3 canines, and 27 deer. Only 22 deer, 7 canines, and 15 tick <it>flaB</it> amplicons (12 <it>I. scapularis</it>, 2 <it>A. maculatum</it>, and 1 <it>Amblyomma</it> species) were homologous with <it>B. burgdorferi</it> sequences.</p> <p>Conclusions</p> <p>Data from this study identified multiple Borreliae genotypes in Arkansas ticks, canines and deer including <it>B. burgdorferi</it> and <it>B. lonestari;</it> however, <it>B. lonestari</it> was significantly more prevalent in the tick population than <it>B. burgdorferi</it>. Results from this study suggest that the majority of tick-borne diseases in Arkansas are not <it>B. burgdorferi.</it></p