Looking north and thinking ahead: Understanding the range expansion of vector-borne cervid pathogens
Date of Award
2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Alison Brody
Second Advisor
Ellen Martinsen
Abstract
Emerging infectious diseases (EIDs) are rising in incidence around the world. EIDs not only pose a threat to human and animal well-being, but can have negative consequences for biodiversity. Vector-borne pathogens are of particular concern as their complicated life cycles are especially affected by climate and land-use changes. The blood parasites Plasmodium odocoilei, Babesia odocoilei, and Theileria cervi pose a threat to northern cervid populations, such as moose (Alces alces) and caribou (Rangifer tarandus), as their arthropod vectors and white-tailed deer (Odocoileus virginianus) hosts expand northward in range. Babesia odocoilei was also recently found to be pathogenic in humans. However, there is a dearth of knowledge on the prevalence and distribution of these pathogens in the Northeastern United States (US). By forging collaborations with each state fish and wildlife agency in New England, I obtained 576 tissue samples from free-ranging white-tailed deer (N=412) and moose (N=164). By conventional PCR, I screened the cervid tissue samples for P. odocoilei, B. odocoilei, and T. cervi. The pathogens P. odocoilei and B. odocoilei exhibited relatively broad presence in white-tailed deer across New England but with low prevalence (5.81% and 1.96%, respectively). Theileria cervi exhibited a high prevalence (44.89%) within the established range of the lone star tick (Amblyomma americanum) vector. Within the same range, juvenile white-tailed deer were more likely to be infected with T. cervi than adult deer (p=0.053). Modeling T. cervi infection probability in white-tailed deer as a function of various environmental factors revealed that percent deciduous forest was the best supported predictor. The moose did not test positive for B. odocoilei or T. cervi, and only one Vermont moose calf tested positive for P. odocoilei. This is the first documentation of a malaria parasite in a moose. This study establishes foundational knowledge on the prevalence and distribution of these pathogens in northeastern US cervids. These baseline data offer a platform for future research into the dynamics of vector-borne pathogens, particularly in understanding their responses to climate and land use changes.
Language
en
Number of Pages
59 p.
Recommended Citation
Berkley, Lauren, "Looking north and thinking ahead: Understanding the range expansion of vector-borne cervid pathogens" (2024). Graduate College Dissertations and Theses. 1903.
https://scholarworks.uvm.edu/graddis/1903