Are there 'hot spots' of bovine tuberculosis in the free-ranging white-tailed deer (Odocoileus virginianus) herd of northeastern Michigan?

摘要

This project looks at whether high case frequency areas or "hot spots" of bovine tuberculosis (tb) exist in free ranging white-tailed deer in northeastern Michigan, and examines the factors associated with them. Michigan Department of Natural Resources researchers have been collecting deer heads annually since 1996 in the five county area of Alcona, Alpena, Montmorency, Oscoda, and Presque Isle as part of an effort to manage an outbreak of bovine tb in the wild white-tailed deer population. From these heads a database containing age, sex, and harvest or collection location information was constructed. The townships within these five counties were categorized as having zero case frequency, medium case frequency, or high case frequency. These categories are based on the number of years at least one tb infected deer was detected in that township. Each case frequency category was then examined individually looking at the yearly sample size distributions, yearly case frequency, and cumulative sample size distributions. Using GIS these areas of varying case frequency were compared to five deer use categories, Summer Use (high quality summer habitat), Summer Other (poor summer habitat), Winter Use (high quality winter habitat), Winter Other (poor winter habitat), and Rare Use (includes areas rarely or never used by deer, such as water, urban and industrial areas).