Gaps and opportunities in on-host winter tick (Dermacentor albipictus) surveillance in North America

Abstract

The investigation and management of the impacts of winter tick (Dermacentor albipictus) infestations on moose (Alces alces) in North America necessitates coordinated surveillance and intervention efforts. However, variations in parasite surveillance methods and potential biases towards sampling specific host species for this generalist parasite can impede attempts to standardize observed disease patterns across vast regions and into the future. We collected and classified records of winter tick surveillance on ungulate hosts throughout North America to identify trends and biases in species, space, and time, with the aim of identifying gaps and suggesting improvements to existing practices. We conducted a literature review spanning a century of winter tick reports on free-roaming or wild ungulate hosts in North America, resulting in 125 relevant records. From this sample, we compiled information on host species and surveillance method details and categorized winter tick quantification techniques based on their perceived insight for analyses and interventions, assigned as an ecological information value (Eco-IV) ranging from 0 to 3. We examined variations in Eco-IV among free-roaming ungulates based on species, literature type, and data source. Among the 18 identified ungulate hosts, moose, white-tailed deer (Odocoileus virginianus), and elk (Cervus canadensis) were most frequently reported. We observed a higher Eco-IV for moose, indicating an abundance of species-specific information, and a lower Eco-IV (less information available) for methods focusing on white-tailed deer. Limited sample sizes prevented the identification of patterns of knowledge acquisition for elk. Eco-IVs in other ungulate species were consistently lower than moose, white-tailed deer, and elk, regardless of literature type or data source. Exotic and invasive species systematically lacked detailed methods (Eco-IV = 0). These findings highlight significant information gaps that impede the ability to compare winter tick infestation rates across studies, geographic regions, and host species, thus hindering coordinated management actions. We recommend standardizing winter tick quantification methods for all ungulate host species, specifically other common winter tick hosts such as white-tailed deer and elk, and increased communication among groups working on tick–host systems to address these gaps.