Environmental factors affecting the range expansion of Ixodes scapularis, the blacklegged tick, (Acari:Ixodidae) in Illinois

Cimo-Dean, Erica

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https://hdl.handle.net/2142/114101 Copy

Description

Title

Environmental factors affecting the range expansion of Ixodes scapularis, the blacklegged tick, (Acari:Ixodidae) in Illinois

Author(s)

Cimo-Dean, Erica

Issue Date

2021-12-06

Director of Research (if dissertation) or Advisor (if thesis)

Stone, Chris

Committee Member(s)

• Tuten, Holly
• Allan, Brian
• Lara, Mark

Department of Study

Entomology

Discipline

Entomology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• I. scapularis
• ticks
• Lyme disease
• ecology
• vector borne disease
• range expansion

Abstract

Tick-borne pathogens are zoonoses whose transmission ecology involves complex interactions among the environment, competent reservoir or reproductive hosts, ticks acting as vectors, humans and their companion animals. Ixodes scapularis (Acari:Ixodidae) Say, 1821, the blacklegged tick, is an important vector of the disease agents of Anaplasmosis, Babesiosis, Powassan virus disease, Ehrlichiosis (Ehrlichia muris eauclairensis), Borrelia miyamotoi disease, and several strains of spirochetal bacteria which can cause Lyme disease. Both the human prevalence of Lyme disease and distribution of I. scapularis have been increasing in Illinois. Acquisition of pathogens by I. scapularis ticks is highly dependent on a variety of biotic and abiotic factors affecting both their life history traits and that of their hosts. Small, fragmented forested patches are less likely to sustain extensive species diversity and may host large populations of pathogen reservoir hosts such as the white-footed mouse (Peromyscus leucopus) and eastern chipmunk (Tamias striatus) while providing abundant edge habitat for large mammal I. scapularis reproductive hosts, such as white-tailed deer (Odocoileus virginianus). Dominant tree species may also influence the presence and success of various animal hosts. Soil composition, elevation, and drainage may impact the survival and overwintering success of ticks. As part of the statewide surveillance program of ticks and their pathogens in Illinois during the autumn seasons of 2019 and 2020, a total of 283 adult female I. scapularis were collected via drag sampling. At least five 150 meter transects were sampled per site. The abundance of I. scapularis was established in 28 of 44 sampled counties across Illinois. To assess the effect of forest fragmentation, soil composition, elevation, proximity to water bodies, climate, natural divisions and dominant tree species on the abundance of I. scapularis in Illinois, I developed a General Additive Model that accounted for spatial structure, using remote sensing data at scales most pertinent to two hosts important to the life cycle of I. scapularis, a buffer with a radii of 100 m to examine activity of the white-footed mouse, and a buffer with a radii of 900 m for the white-tailed deer. At the scale most relevant to the activity of the white-tailed deer, metrics related to habitat fragmentation such as number of patches (NP) (p=<0.001) and mean area (AREA_MN) (p=<0.001) were predictive of adult female I. scapularis abundance, meaning as patch number increased, and mean area decreased, adult female I. scapularis abundance increased. At the scale most relevant to the activity of the white-footed mouse, distance further from a body of water was positively correlated with I. scapularis tick abundance (p= 0.006). Latitude and longitude (spatial coordinates) were found to be significantly associated with tick abundance indicating that the density of I. scapularis varies across the state, with I. scapularis abundance higher in the northern portion of the state, rather than central and southern Illinois. The results of this study indicate that habitat fragmentation metrics including patchiness of the landscape and patch size influenced tick abundance more than other environmental factors like soil textures and proximity to water bodies.

Graduation Semester

2021-12

Type of Resource

Thesis

Permalink

http://hdl.handle.net/2142/114101

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Copyright 2021 Erica Cimo-Dean

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