Sudden Mortality in Captive White-Tailed Deer With Atypical Infestation of Winter Tick

Abstract

In October 2020, three captive male white-tailed deer, Odocoileus virginianus [Zimmermann] (artiodactyla: Cervidae), were found dead in central Pennsylvania and a fourth was euthanized due to extreme lethargy. The deer presented with high burdens of Dermacentor albipictus (Packard) (Ixoda: Ixodidae) (winter tick). There were no other clinical symptoms and deer were in otherwise good physical condition with no observed alopecia. Winter tick epizootics have been associated with mortalities of moose, Alces alces [Linnaeus] (artiodactyla: cervidae), and more recently elk, Cervus canadensis [Erxleben] (artiodactyla: cervidae), in Pennsylvania, but have not been reported in white-tailed deer. Mild winters are favorable to winter ticks and deer producers and managers should be aware of possible infestations as a result.

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

“…We do not have records in our database for nonmoose hosts on the basis of hair loss alone, but it should be noted that most cervids do exhibit some degree of winter tick‐induced alopecia (Calvente et al, 2020; Normandeau et al, 2022; Welch et al, 1991), even if this is usually less severe than in moose. Extremely high host burdens of winter tick have been found on woodland caribou ( Rangifer tarandus caribou ) and white‐tailed deer when hair loss has been absent (Machtinger et al, 2021; Welch et al, 1990), so the reliability of this indicator on nonmoose species may be limited, particularly when compared with conventional necropsy techniques.…”

“…Extremely high host burdens of winter tick have been found on woodland caribou (Rangifer tarandus caribou) and white-tailed deer when hair loss has been absent (Machtinger et al, 2021;Welch et al, 1990), so the reliability of this indicator on nonmoose species may be limited, particularly when compared with conventional necropsy techniques.…”

“…The species remains notorious for high abundance infestations on moose, with severe infestations of 80,000–100,000 ticks per individual observed, along with distinctive patterns of hair loss (McLaughlin & Addison, 1986; Mooring & Samuel, 1998; Samuel, 2004). Since the early 1900s, mass die‐offs of moose with winter tick infestations have been reported in Canada (Cameron & Fulton, 1927; Merrill, 1916) and the United States (Dunfey‐Ball, 2017; Jones et al, 2019), with recent mortality events in wild elk ( Cervus elaphus canadensis ) (Calvente et al, 2020) and captive white‐tailed deer ( Odocoileus virginianus ) (Machtinger et al, 2021), indicating that species other than moose may also be at risk from the effects of hyperabundance.…”

“…Host ranges are from International Union for the Conservation of Nature Red List assessments(IUCN, 2019a(IUCN, , 2019b(IUCN, , 2019c(IUCN, , 2019d, orange outlines indicate states and provinces where specified host species die-offs have been reported. References for die-offs: moose(Cameron & Fulton, 1927; Canadian Wildlife Health Centre [CWHC], 1999, 2002Dunfey-Ball, 2017;Merrill, 1916;Pybus, 1999;Samuel, 2007;Samuel & Barker, 1979), elk(Bishopp & Wood, 1913;Calvente et al, 2020), white-tailed deer(Machtinger et al, 2021; United States Department of Agriculture [USDA], 1967).…”

Tick Control in a Connected World: Challenges, Solutions, and Public Policy from a United States Border Perspective

“…One such challenge is climate change, which is implicated in current and future alterations to geographic ranges and population densities of several tick species of medical and veterinary importance [10]. High infestation burdens and associated mortalities due to Dermacentor albipictus (winter tick) on moose (Alces alces) and other cervids and the range expansion of I. scapularis are both partially attributed to the effects of climate change [11][12][13][14][15]. Warmer temperatures, particularly warmer winters, are hypothesized to be a leading factor associated with I. scapularis range expansions across eastern and central Canadian provinces [16].…”