Host Reduction

White-tailed deerThe motivation behind host reduction is that tick abundance will be substantially suppressed following the reduction of a significant number of hosts. For example, the reduction of several major hosts of blacklegged ticks has been proposed, although the only actual host reduction research focused on the removal of white-tailed deer from an island ecosystem. After attempts to live-trap deer proved impractical, hunting was used to cull the herd. Removal of 70% of deer did not markedly reduce tick abundance. The failure to reduce tick numbers in the short term can be explained if ticks used alternate hosts or if the density of ticks increased on the remaining deer. In a subsequent study, the virtual eradication of deer eventually resulted in significant reduction of the tick population. Notwithstanding the partial success of these studies, the use of host reduction as a means to reduce tick populations has ecological, sociological, and political drawbacks.

A mouseThe first problem with the deer reduction studies was that they were conducted in geographical isolation. Compared to mainland situations, islands often lack the diversity and abundance of alternative hosts. Aside from the many logistical obstacles to implementing a control program, maintaining reduced local deer populations in mainland situations, where recolonization by deer from surrounding areas is typically rapid, may not be practical. Even if moderately successful, culling programs are often limited by municipal ordinances prohibiting discharge of firearms or by public opposition to lethal removal methods, as evidenced by the negative public response to several municipally sponsored deer reduction efforts in New Jersey. Given the politically, and often emotionally, charged climate surrounding urban deer management, the widespread destruction of this important game animal is not a viable option to reducing tick populations and disease transmission.