University of Wisconsin–Madison

Maps of the distribution of the deer tick in Wisconsin

There are three surveillance maps here.  The first map summarizes recent results from passive surveys where partners collect and send ticks to UW-Madison.  The second map summarizes results of all active surveys.  This includes surveys on hunter killed deer as well as sampling small mammals or dragging vegetation for ticks.  The third map shows the results of surveys of hunter killed deer to illustrate differences in tick density across the state..

Important Note: In the few counties or areas where there has been no surveillance for ticks ) or where very few to no ticks were found, this does not mean that there are no ticks present or little to no risk of tick-borne disease within these counties.

Figure 1.  Results of passive surveys for Ixodes scapularis (deer ticks) in Wisconsin. Veterinary clinics, humane societies, and animal rehabilitators collected ticks from animals and sent them to UW-Madison for identification.Deer ticks_Passive surveillanceFigure 2.  Results of active surveys for Ixodes scapularis deer ticks in Wisconsin.  Red indicates the county was positive for deer ticks (at least one nymph or adult tick found) by sampling of the vegetation, small mammals or white tailed deer between 2008 and 2013.  Yellow indicates a county was positive in surveys done prior to 2008.  Green indicates that no ticks were found in surveys.  White indicates a county has not been surveyed by any active method.

Map of tick presenceFigure 3.  Survey for adult Ixodes scapularis on deer harvested on the first or second day of gun-deer season. The darker part of each pie graph represents the percent of all deer at a site that had at least one deer tick; lighter portion of the pie chart represents the percent of all deer at a site that were uninfested.  The map gives a better indication of the intensity of infestation, with the lowest levels in the eastern-most part of the state. See the spotlight article on changing distribution for maps showing older surveys.

2008 09 survey


Lee, Xia, Hardy, K. Johnson D. and Paskewitz S.M. “Hunter-Killed Deer Surveillance to Assess Changes in the Prevalence and Distribution of Ixodes scapularis (Acari: Ixodidae) in Wisconsin.” Journal of medical entomology 50.3 (2013): 632-639.