Prevalence of Rickettsia in ticks collected near I-90 in Upper Kittitas County

Ticks transmit more pathogens than any other group of blood-feeding arthropods, causing disease in humans as well as domestic and wild animals. Rickettsia is a genus of bacteria that is transmitted by arthropod vectors, including ticks. Dermacentor ticks become infected with Rickettsia by feeding on infected mammals and/or through vertical transmission from parent to offspring. Rickettsia is transmitted to humans through tick bite, suggesting that rickettsia is localized in the salivary glands of the tick. Spotted fever group (SFG) Rickettsia cause human disease and is seen predominantly in the southeastern United States during mid-spring through late summer. Spotted fever rickettsioses also occurs in Washington but little research has been done on the prevalence of pathogenic and non-pathogenic Rickettsias in eastern Washington. In this study, we collected ticks from small mammals trapped along the I-90 corridor. DNA was extracted from twenty ticks and analyzed by polymerase chain reaction (PCR) to detect bacterial DNA. Forward and reverse primers of Rr190.70 were used to identify the presence of Rickettsia DNA. Of the 20 ticks tested, 16 (80%) were positive for Rickettsia. Screening ticks for disease-causing pathogens provides useful epidemiological information on their distribution and the prevalence of pathogens that pose veterinary and medical health risks