The Lyme Disease Spirochete, <i>Borrelia burgdorferi</i>, in Tick Species Collected from Raccoons (<i>Procyon lotor</i>) and Opossums (<i>Didelphis virginiana</i>) Trapped in the Warren and Barren Counties of South Central Kentucky

The incidence of tick-borne zoonoses such as Ehrlichiosis, Rocky Mountain Spotted Fever, and Lyme disease has steadily increased in the southeastern United States in recent years. According to the Centers for Disease Control and Prevention (CDC), the southeastern states accounted for 1,200 of the 27,000 total cases of Lyme disease reported in the U.S. in 2007. Although <i>Ixodes scapularis</i> is the most commonly recognized vector for the Lyme disease spirochete <i>Borrelia burgdorferi</i>, <i>Dermacentor variabilis</i> (a common vector for Rocky Mountain Spotted Fever) also has been shown to be a viable host for this pathogen. The purpose of the present study was to use PCR and DNA sequencing technologies to determine if <i>Borrelia burgdorferi sensu lato</i> is present in ticks and whole blood samples removed from raccoons and opossums trapped in south-central Kentucky. <br> Raccoons and opossums were trapped in Barren and Warren counties of Kentucky between June 2007 and June 2008. Ticks were removed and stored in 70% ethanol. Sterile blood samples were collected into three 10 ml tubes containing the anticoagulant K2EDTA and stored at 4°C. Genomic DNA was extracted from ticks and blood samples using a QIAamp DNA mini kit and a QIAamp DNA blood mini kit (Qiagen) respectively. DNA samples were analyzed by polymerase chain reaction (PCR) for the presence of <i>B. burgdorferi</i> using oligonucleotide primers specific for the OspA gene.<br> A total of 976 ticks were collected. Three different species were obtained from raccoons; <i>Dermacentor variabilis, Amblyomma americanum</i>, and <i>Ixodes sp</i>. <i>Dermacentor variabilis</i> was the only tick species found on opossums. Twenty-five percent (163/642) of the tick DNA samples were positive for <i>Borrelia burgdorferi</i>. Prevalence of <i>B. burgdorferi</i> by tick species was 24.4% (141/577) in <i>D. variabilis</i>, 40.6% (13/32) in <i>A. americanum</i>, and 27.6% (8/29) in <i>I. scapularis</i>. In the present study, 15.7% (8/51) of the total raccoon blood samples examined by PCR were positive for <i>B. burgdorferi</i>, while no opossum blood samples were positive. The high prevalence of <i>B. burgdorferi</i> in ticks common to raccoons and opossums observed in this study, as well as in a tick species that aggressively bites humans in the southeast U. S. (<i>A. americanum</i>), creates concern that there are ample opportunities for people to come in contact with the infected ticks on these animals. Future studies are urgently needed to fully assess the presence and prevalence of <i>B. burgdorferi</i> in Kentucky and other southeastern states in the U. S.

Name thesis:degree_name

Master of Science

Discipline thesis:degree_discipline

Department of Biology

Year

2009

Author dc:creator

• Tackett, Kristina

Contributors dc:contributor

• Dr. Cheryl Davis (Director), Dr. Nancy Rice, Dr. Rodney King

• lyme disease
• public health
• tick-Borne pathogens
• genome sequence
• Cell Biology
• Genetics

Repository record dc:identifier

https://digitalcommons.wku.edu/theses/118

OAI identifier oai:identifier

oai:digitalcommons.wku.edu:theses-1118