Date Thesis Awarded


Access Type

Honors Thesis -- Access Restricted On-Campus Only

Degree Name

Bachelors of Science (BS)




Matthias Leu

Committee Members

Oliver Kerscher

Ashleigh E. Queen


Tick-borne diseases pose an immense threat to human health. Lyme disease in particular is increasing in both geographic range and case numbers in recent decades. Surveillance of the prevalence of Borrelia burgdorferi, the causative agent of Lyme disease, is essential to understanding the spatial distribution of infection risk. The blacklegged tick (Ixodes scapularis) is one of the primary vectors for B. burgdorferi. Using a long-term data set, we compared annual variation in prevalence of B. burgdorferi between nymph and adult blacklegged ticks. We also investigated how prevalence varied spatially and related variation in prevalence to weather and land-cover data that were proxies for blacklegged tick hosts. We consistently sampled 105 plots located at 15 different sites in southeastern Virginia once a year from 2015 – 2019, and an additional 20 plots during some but not all years. We used a PCR-based technique to determine prevalence of B. burgdorferi in nymphs and adults separately. The average prevalence of B. burgdorferi in nymphs over our five-year study period was 0.10 (credible interval = 0.05 – 0.17) and 0.39 (credible interval = 0.28 – 0.51) for adults. Temporal variation in prevalence was higher in adults than nymphs ranging between 0.13 and 0.60 for adults and 0.05 and 0.25 for nymphs. Our research also suggests a high turnover of B. burgdorferi in our study area, with one site never testing positive, and the rest having plots that tested positive a maximum of two out of five years. Sites that tested positive most frequently were in areas with low-density urban development. We were unable to relate the variation of B. burgdorferi prevalence to either land-cover or weather predictor variables. This suggests that long-term studies are needed to elucidate the patterns and factors present in this complex interaction of hosts, ticks, and bacteria. Our research provides important information about B. burgdorferi prevalence and Lyme disease risk, which can be used to inform health policies.

Available for download on Saturday, May 11, 2024

On-Campus Access Only