Topographical and Climatic Factors Influencing the Distribtion of D. andersoni Across Western Montana

Abstract

The Rocky Mountain wood tick, Dermacentor andersoni, has a high prevalence in the Western United States and is a known vector for Colorado Tick Fever, Rocky Mountain spotted fever and other infectious diseases. Though prevalent, their distribution is still poorly understood. The goal of this study was to examine topographical and climatic factors influencing D. andersoni’s distribution over Western Montana. This study consists of data collected from 145 total sites from 2013 to 2016. At each site, ticks were captured using a drag sampling technique and were categorized in terms of abundance. Various climatic and topographical data were obtained on-site and through the National Elevation Dataset, NASA Earth Observation and the PRISM Climate Group. The study found that May Normalized Difference Vegetative Index (NDVI), average spring precipitation and average summer temperatures were significant in distinguishing between sites of different D. andersoni abundance.