Ixodes scapularis (Acari:Ixodidae): status and changes in prevalence and distribution in Wisconsin between 1981 and 1994 measured by deer surveillance.

A statewide survey of blacklegged ticks, Ixodes scapularis Say, on white-tailed deer was conducted in 1994 to examine the status and changes in the prevalence and geographic distribution of this tick in Wisconsin. I. scapularis adults were collected at 17 of 26 deer registration stations, including stations in eastern (Poy Sippi) and southern Wisconsin (Monroe) without previously reported populations. Nearly all of the stations where 1 or no ticks were collected were in the eastern 1/3 of the state. The prevalence of I. scapularis in 1994 was compared with prevalence estimates taken in similar surveys during 1981 and 1989. A significant increase in tick prevalence occurred at stations along the Wisconsin River Valley, which previously defined the edge of the eastern range of I. scapularis populations and in southern Wisconsin.