Dead deer do tell tales: infestation of road-killed white-tailed deer by juvenile Ixodes scapularis (Ixodida: Ixodidae) ticks.

The white-tailed deer (Odocoileus virginianus) contributes indirectly to the enzootic circulation of the Lyme disease pathogen, Borrelia burgdorferi by serving as the primary reproductive host for adult-stage blacklegged ticks (Ixodes scapularis). The role of white-tailed deer as a host for juvenile life stages is less well understood, in part because their periods of activity typically fall outside of most white-tailed deer hunting seasons. We inspected 22 road-killed deer for all stages of blacklegged ticks in Rutland County, Vermont from May to August in 2020, 2021, and 2024. Adult-stage blacklegged ticks were found attached to ten deer in May and early June. Larval-stage ticks, including ones that were partially engorged, were found on 3/5 deer inspected by hanging the head, hide, and legs over water for approximately 24 hours. We directly observed 7 nymphal-stage ticks attached to one additional deer. This study adds to a growing body of evidence that the role of juvenile feeding on white-tailed deer may be underestimated and demonstrates that the study of road-killed deer may improve our understanding of how populations of blacklegged ticks are maintained among wildlife communities.