Year of Graduation

2021

Document Type

Thesis

Major

Biology

Directing Professor

Drs. Elizabeth R. Gleim and Holly D. Gaff

Abstract

Annual Lyme disease cases continue to rise in the U.S. making it the most reported vector-borne illness in the country. The pathogen (Borrelia burgdorferi) and primary vector (Ixodes scapularis; blacklegged tick) dynamics of Lyme disease are complicated by the multitude of vertebrate hosts and varying environmental factors, making models an ideal tool for exploring disease dynamics in a time- and cost-effective way. In the current study, LYMESIM 2.0, a mechanistic model, was used to explore the effectiveness of three commonly used tick control methods: habitat-targeted acaricide (spraying), rodent-targeted acaricide (bait boxes), and white-tailed deer targeted acaricide (4-poster devices). Work was done to evaluate their effectiveness when used alone and in combination with one another. Optimized application strategies were also identified. Additionally, pilot work was done to incorporate prescribed fire into the model and compare its efficacy to the acaricide-based approaches. It was determined that any singular use or combination of methods that included spraying were most effective amongst acaricide-based treatments, suppressing the density of I. scapularisnymphs (DON) by >80%. Furthermore, the best time to apply treatments was between January and mid-April, and mid-September to early December. Optimized treatment strategies identified by the model include application of treatment twice annually, every other year at a minimum effectiveness of 25%, which achieves 80% DON suppression and no increases in I. scapularis nymphs once treatments are complete. Interestingly, preliminary work to integrate prescribed fire in the model indicated that it achieved 93-100% efficacy in burn years and one-year post burn, making prescribed fire more effective than all acaricide-based treatments. Overall, this study illustrates the value in using models to identify the best method of blacklegged tick population control that is both time- and cost-effective. Future field research should be done to validate the findings of this model.

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