Marina McManus

Document Type

Honors Thesis

Major

Animal & Veterinary Sciences

Advisor(s)

Pauline Kamath

Committee Members

Allison Gardner, M. Scarlett Tudor, Jordan LaBouff

Graduation Year

May, 2026

Publication Date

2026

Abstract

Moose (Alces alces) serve a variety of cultural, economic, and ecological roles. In the Northeastern United States, however, moose populations are threatened by several parasite infections. Winter ticks (Dermacentor albipictus) have been directly associated with moose calf mortality over the past decade, causing anemia and impacting the individual’s health. In addition, coinfection with bloodborne parasites, such as Anaplasma spp. and Babesia spp., may decrease a calf’s chance of survival through the first winter. Infection status may also impact reproduction, for example, by causing abnormal development of key secondary sexual characteristics such as antlers. Babesia spp. have been identified in moose in Canada and other regions, but the parasite’s prevalence, distribution, genetic diversity, and transmission dynamics have not yet been investigated in the Northeastern U.S. The objectives of this study are (1) to determine which species of Babesia is infecting moose in the state of Maine and estimate the infection prevalence, (2) to determine if winter ticks (Dermacentor albipictus) are a potential vector of B. odocoilei, and (3) evaluate whether secondary sexual characteristics, like antler spread and points, are impacted by blood-borne parasites (Anaplasma spp.). I estimated the prevalence of Babesia spp. in both hunter harvested (n = 347) and live captured moose calves (n = 306) using samples collected in 2021-2024, finding an estimated prevalence of 2.6% in the hunter harvested moose and 5.9% in the live captured calves. I identified Babesia odocoilei as the sole Babesia spp. present within moose across the state of Maine. I did not find any winter ticks to be positive with Babesia spp. from the paired samples (n = 271 ticks from 92 moose), suggesting they may not play a role in Babesia transmission. I found that moose with Anaplasma infections tended to have shorter antler spread and less antler points than moose without the infection (n = 172). This study demonstrates the importance of Babesia spp. in Maine moose, highlights future directions for studies on babesiosis in cervids, and illustrates that traits important for reproduction may be impacted by blood-borne pathogens.

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