Revealing large‐scale parasite ranges: An integrated spatiotemporal database and multisource analysis of the winter tick

Abstract

Concerns that climate warming may drive the spread of ectoparasites into previously uninhabited areas have increased the need for baseline knowledge of their distributional history. For species of wildlife health concern, presence data are often lacking or outdated, thus limiting our ability to assess range changes and subsequent host impacts. We reconstructed the past and present distribution of the winter tick, Dermacentor albipictus, through the compilation of a spatiotemporal database to create the first full baseline map of its occurrence throughout its North American range. The ongoing impacts of winter tick epizootics in moose (Alces alces) and recent mortality events in elk (Cervus canadensis) and white‐tailed deer (Odocoileus virginianus) have led to a resurgence in interest in the future of this parasite in a warming climate. Over 3400 unique records of winter tick occurrence were compiled from multiple data sources, dating from 1869 to 2020 and spanning from 16.5 to 66.2° N latitude. Both conventional published sources and natural history records were included along with new records from previously unpublished datasets and citizen science observations, to make this a comprehensive occurrence dataset for this species. Along with standardized location information and year of observation, the dataset includes associated host species and descriptive categorization of the type and source of each record, providing new opportunities to examine host–parasite interactions in the winter tick system over time and space. In presenting these data, we discuss the potential sampling biases and lacunas in our integrated database records, particularly at the winter tick's northernmost range. We also document changes in the types and sources of winter tick information from past to present, highlighting potential issues that should be considered before using these data in further analyses and when collecting ongoing records. Our database demonstrates that the collation and synthesis of records beyond conventional sources can shed light on the distributional history of tick species and serve as a useful baseline for prioritizing future research and management decisions.

Apparent fatal winter tick (Dermacentor albipictus) infestation in captive reindeer (Rangifer tarandus)

“…Namely, lack of tick infestation estimates, absence of pathogen assessment in the animals’ carcasses, incomplete pathogen assessment (particularly for A. marginale and B. duncani ) in ticks. However, despite the limitations of the report necropsy findings and sudden death corroborate previous associations between heavy winter tick infestation and death of animals ( Welch et al, 1990a ; Calvente et al, 2020 ; Machtinger et al, 2021 ; Chenery et al, 2023 ). In addition, none of the ticks tested were positive for specific protozoan and rickettsial tick-borne pathogens via molecular screening.…”

“…Our report highlights that domestic reindeer reared in areas of North America where D. albipictus is endemic should be closely monitored for tick infestation and possibly undergo periodic or preventive acaricide treatment to reduce the risk of tick infestation and potential death. Similarly, translocation of caribou for conservation efforts or transportation of domesticated reindeer across areas of the United States and Canada may further contribute to range expansion and establishment of D. albipictus into new areas, which has been widely reported in the literature ( Chenery et al, 2023 ) . Hence, it is crucial to improve the vigilance regarding ectoparasite infestations in these animals.…”

Monitoring questing winter tick abundance on traditional moose hunting lands

“…Although location occurred in the top models in the N‐mixture model set, high variance masked any potential differences between study areas. We expected to find ticks at all study sites (Chenery et al 2023), but we hypothesized that the STL and WMU study site would support the highest tick abundance and probability of site occupancy. Winter tick epizootics are hypothesized to be density dependent, and primarily affecting moose in high‐density populations in New Hampshire, Vermont, and western Maine (Samuel 2004, Healy et al 2018, Pekins 2020).…”

Warm places, warm years, and warm seasons increase parasitizing of moose by winter ticks

“…Whereas multiple tick species carry pathogens of importance to human health (Dantas‐Torres et al, 2012), the winter tick ( Dermacentor albipictus ) instead is notable for its effects on wildlife, in particular ungulates (hoofed‐mammals). Winter ticks parasitize multiple ungulate species across North America (Chenery et al, 2023) but have most strongly affected moose ( Alces alces ) populations (Welch et al, 1991). Epizootics of winter ticks have been linked to decreased calf survival and population performance in New Hampshire, Maine, and Vermont (DeBow et al, 2021; Ellingwood et al, 2020; Jones et al, 2019), as well as to moose population crashes in Alberta (Samuel, 2007).…”