MICHELLE BELL
A Pilot Study to Evaluate the Methodology of Collecting and PCR Analysis of Rodents and Ticks to Identify the Disease Agents, Vectors, and Reservoirs of
Lyme Disease and Human Ehrlichioses
Industrial Hygiene and Safety, MS
Preceptor: Charles Treser, MPH
Every year human cases of tick borne diseases are reported in Western Washington (DOH, 2000). Despite the presence of known and suspected vectors for Lyme disease and Human Granulocytic Ehrlichiosis in Western Washington, (Spach, 1997) the epidemiologic link between human cases of tick borne disease and sources of exposure has not been systematically investigated.
The population distribution of ticks and prevalence of disease agent carriage by ticks in Western Washington State is poorly understood. Current knowledge is based on a ten and twenty year old data collected in Washington and Oregon by academic and public health organizations. The following study is a descriptive survey to update data regarding the vector and reservoir distribution and document disease agent carriage of Lyme disease and Human Ehrlichioses in Thurston County, Washington. Its goals are to determine and describe the distribution of vectors, reservoirs, and disease agents by habitat.
Ticks and rodents were collected from four typical habitat types found in Thurston County. Samples were obtained from: Meadow, Riparian, Conifer and Hardwood habitats geographically dispersed. Tick, rodent blood, and rodent ear samples were analyzed using polymerase chain reaction (PCR) for Borrelia burgdorferi, Ehrlichia chaffeensis, and the infectious agent for Human Granulocytic Ehrlichiosis (HGE). None of the two hundred and thirty four analyses of one hundred and thirty five ticks and thirty six mice were positive for tick borne disease pathogens.
